Co-reporter:Huihui Yuan, Jing Xue, Bin Qian, Huaying Chen, Yonggang Zhu, Minbo Lan
Applied Surface Science 2017 Volume 394() pp:403-413
Publication Date(Web):1 February 2017
DOI:10.1016/j.apsusc.2016.10.083
Highlights
- •
The hydrophilic and negatively charged PU-CS films were successfully prepared by chemical grafting using N-Boc-1,3-propanediamine as a spacer and the chondroitin sulfate (CS) grafting density on PU films can be controlled by the mass fraction of the spacer.
- •
The impacts of the CS grafting density on the adsorption of proteins and adhesion of glycosaminoglycans were evaluated.
- •
The impact of inorganic salt deposition after conditioning film formation (co-adsorption of proteins and polysaccharides) on PU and PU-CS(3) film was investigated with artificial urine samples.
Co-reporter:Xiaoqing Li, Hongli Zhao, Libo Shi, Xiang Zhu, Minbo Lan, Qian Zhang, Z. Hugh Fan
Journal of Electroanalytical Chemistry 2017 Volume 784() pp:77-84
Publication Date(Web):1 January 2017
DOI:10.1016/j.jelechem.2016.12.009
Rapid and accurate detection of nicotine is important due to its detrimental effects on human beings and recent surge in the usage of electronic cigarettes. In this paper, we report an electrochemical sensor for nicotine detection by using screen-printed carbon electrodes (SPCE) modified with nitrogen-doped graphene sheets (NGS). NGS was synthesized and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectrometry. Due to the superior electron transfer capability and the doped nitrogen atoms, NGS shows high catalytic activity for the electro-oxidation of nicotine, with a significant decrease in the overpotential. Using the NGS-based nicotine sensor, we obtained detection sensitivity at 0.627 mA·cm− 2 mM− 1 with the limit of detection at 47 nM nicotine. Moreover, the sensor shows favorable selectivity and long-term stability for detecting nicotine in urine and tobacco samples.
Co-reporter:Huihui Yuan, Bin Qian, Huaying Chen, Minbo Lan
Applied Surface Science 2017 Volume 426(Volume 426) pp:
Publication Date(Web):31 December 2017
DOI:10.1016/j.apsusc.2017.06.314
•The composition and properties of conditioning film formed on PU-CSs with different CS grafting density were investigated.•The impact of conditioning film on subsequent inorganic salt deposition and bacteria adhesion on PU-CSs surface in urine was estimated.•The anti-encrustation properties of the surface was promoted by proteins and inhibited by polysaccharides.The encrustation and induced infection severely impact on the therapeutic effectiveness and service life of urinary stents due to the fast formation of conditioning film on urinary stents after implantation. The composition and properties of conditioning film have great influence on antifouling properties of stent materials. In our previous work, we modified polyurethane films by chondroitin sulfate (PU-CS) with different CS grafting densities to verify its anti-fouling properties. To obtain the in-depth understanding of encrustation on urinary stents, we investigated the impact of the composition and properties of conditioning film on the following inorganic salt deposition and bacteria adhesion in urine. The results showed that quantity of proteins and polysaccharides in conditioning films, and the roughness, water contact angle and zeta potential of PU-CSs covered with corresponding conditioning film decreased with the increase of CS grafting density on PU films.PU-CS(3) with highest CS grafting density (3.70 g/cm2) had the highest bacteria inhibition rate and least inorganic salt deposition among the PU-CSs in artificial urine. Moreover, inorganic salts depositing on the PU-CS(3) were less and smaller than those on other films. Bacteria were not detectable until day 21 in real urine. Meanwhile, the pH value was elevated. The results suggested that the component of conditioning films was more important than other surface properties such as hydrophilicity, zeta potential and roughness for inorganic salt deposition and bacteria adhesion. Moreover, the anti-encrustation properties of the surface was promoted by proteins and inhibited by polysaccharides.Download high-res image (140KB)Download full-size image
Co-reporter:Yanfang He;Xiangheng Niu;Libo Shi;Hongli Zhao;Xin Li;Wenchi Zhang
Microchimica Acta 2017 Volume 184( Issue 7) pp:2181-2189
Publication Date(Web):05 April 2017
DOI:10.1007/s00604-017-2235-y
The authors describe a photometric method for the determination of free cholesterol based on the oxidation of cholesterol by the catalytic action of the enzyme cholesterol oxidase. The hydrogen peroxide formed is used to oxidize the chromogenic compound 3,3′,5,5′-tetramethylbenzidine (TMB) by exploiting the peroxidase-like activity of carbon nanotube-supported Prussian blue (PB). This enzyme mimic was synthesized from a mixture of ferric chloride and hexacyanoferrate(III) in the presence of intrinsically reducing multi-walled carbon nanotubes. The composite can trigger the formation of a blue-green dye from TMB in the presence of H2O2. The findings were exploited to design a photometric (652 nm) assay that has a linear response in the 4 to 100 μM cholesterol concentration range and a 3 μM detection limit. The practicability of the method was verified by the successful analysis of free cholesterol in human blood samples.
Co-reporter:Li Liu, Hongli Zhao, Libo Shi, Minbo Lan, Hongwei Zhang, Chengzhong Yu
Electrochimica Acta 2017 Volume 227(Volume 227) pp:
Publication Date(Web):10 February 2017
DOI:10.1016/j.electacta.2016.12.182
In this work, a highly sensitive enzyme- and metal-free electrochemical method for superoxide anion (O2−) detection has been developed by employing screen-printed carbon electrodes (SPCE) modified by nitrogen doped hollow mesoporous carbon spheres (N-HMCS). For comparison, solid carbon spheres (SCS) and hollow mesoporous carbon spheres (HMCS) were also synthesized to fabricate the modified SPCE. Compared with SCS/SPCE and HMCS/SPCE, N-HMCS/SPCE displayed a higher electrochemical performance. When applied for electrochemical detection of O2−, N-HMCS/SPCE exhibited a high sensitivity of 1.49 μA cm−2 μM−1, better than SCS/SPCE and HMCS/SPCE and many of enzyme- or metal-based superoxide anion sensors. N-HMCS is expected to become a new generation of sensing materials for electrochemical analysis of O2−.A highly sensitive enzyme- and metal-free electrochemical sensor for superoxide anion (O2−) detection has been developed based on nitrogen doped hollow mesoporous carbon spheres (N-HMCS) modified screen-printed carbon electrodes (N-HMCS/SPCE).Download high-res image (126KB)Download full-size image
Co-reporter:Xiangheng Niu, Libo Shi, Xin Li, Jianming Pan, Runxin Gu, Hongli Zhao, Fengxian Qiu, Yongsheng Yan, Minbo Lan
Electrochimica Acta 2017 Volume 235(Volume 235) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.electacta.2017.03.096
•A simple anodization makes the activity enhancement of SPCEs for the HER.•Increased oxygen-containing functional groups, defect sites, and hydrophilicity.•The activity enhancement depends on anodization conditions.•Excellent durability of anodized SPCEs for the HER.Undoubtedly, electrocatalyzing the hydrogen evolution reaction (HER) is now becoming the subject of extensive studies due to its crucial role in harvesting clean energy. In general, bare screen-printed carbon electrodes (SPCEs) have negligible ability to catalyze the HER due to the lack of effective sites. Here we find that: 1) a facile anodization treatment can improve the electrocatalytic activity of home-made SPCEs with apparently reduced overpotential and increased current density for the HER; 2) the activity enhancement of SPCEs is highly dependent on anodization conditions including electrolyte, treatment time, and anodization potential; 3) the introduction of negatively charged oxygen-containing functional groups during anodization, together with the increased defect sites and hydrophilicity on electrode surface, leads to the promoted activity of anodized SPCEs synergistically. Similar phenomena are also found in other carbon-based electrodes including glassy carbon electrode and carbon nanotube-modified electrode. These findings reported in this work are expected to guide the future design of advanced electrode systems for efficient hydrogen evolution.Download high-res image (87KB)Download full-size image
Co-reporter:Yayun Hong;Chenlu Pu;Hongli Zhao;Qianying Sheng;Qiliang Zhan;Minbo Lan
Nanoscale (2009-Present) 2017 vol. 9(Issue 43) pp:16764-16772
Publication Date(Web):2017/11/09
DOI:10.1039/C7NR05330D
In this work, we fabricated a yolk–shell magnetic composite that contains mesoporous TiO2 as the inner shell and flowerlike NiO as the outer shell (denoted as Fe3O4@H-TiO2@f-NiO) to reduce the limitations of single-component metal oxides in phosphopeptide enrichment. The NiO nanosheets play a synergistic role in phosphopeptide enrichment. And the unique flowerlike structure of NiO with sufficient space can facilitate the reversible insertion/extraction of peptides, which will have less impact on the enrichment process of the inner TiO2 shell. The yolk–shell structure and two types of porous nanostructures endowed this composite with a high surface area (156.58 m2 g−1) and a large pore volume (0.37 cm3 g−1). Owing to the high surface area and combined properties of TiO2 and NiO, the Fe3O4@H-TiO2@f-NiO microspheres showed a better performance for phosphopeptide enrichment than the same material without NiO nanosheets (Fe3O4@H-TiO2). According to the LC-MS/MS results, 972 unique phosphopeptides were identified from HeLa cell extracts with a high selectivity (91.9%) by Fe3O4@H-TiO2@f-NiO relative to 837 phosphopeptides (selectivity: 60.2%) by Fe3O4@H-TiO2. The results demonstrated that, compared with single-component metal oxides, composite metal oxides could enhance the selectivity and sensitivity for phosphopeptide enrichment.
Co-reporter:Xiangheng Niu, Hongli Zhao, Minbo Lan
Journal of Power Sources 2016 Volume 306() pp:361-368
Publication Date(Web):29 February 2016
DOI:10.1016/j.jpowsour.2015.12.044
•Two nanosized Pd deposits were spontaneously grown on Ni foam via galvanic replacement.•Different palladic precursors produced discrepant arrangements and coverages of Pd.•Pd-4-Ni had more exposure of Ni atoms adjoined to Pd atoms on the catalytic interface.•Higher catalytic activity of Pd-4-Ni toward MOR than Pd-2-Ni and Pd/C.Methanol, a high-energy substance, is widely used for green fuel cells. However, the sluggish electrochemical methanol oxidation reaction (MOR) on state-of-the-art catalysts still requires for exploring high-performance and low-cost materials to further promote the reaction kinetics at low overpotentials. Here we carried out the first electrocatalytic comparison study of two Ni foam-supported Pd nanomaterials (Pd-2-Ni and Pd-4-Ni, respectively), obtained through the spontaneous galvanic replacement of Ni with different palladic precursors ([PdCl4]2- and [PdCl6]2−, respectively), toward MOR. With replacement, Pd deposits with discrepant arrangements and coverages were grown on the porous Ni support. Compared to commercial Pd/C, both Pd-2-Ni and Pd-4-Ni exhibited better mass activity and catalytic durability for MOR in alkaline media. More interestingly, different palladic precursors made a significant effect on the catalytic performance of the Ni foam-supported Pd deposits. In Pd-4-Ni, the 2:1 stoichiometric replacement of Ni with [PdCl6]2− enabled the incompact arrangement of Pd structures, with more exposure of Ni atoms adjoined to Pd atoms on the catalytic interface compared to Pd-2-Ni. As a result, with the favorable Ni-neighbor-Pd regime and the higher utilization efficiency of Pd atoms, the synthesized Pd-4-Ni catalyst provided a mass activity of approximately 1.5 times higher than Pd-2-Ni toward MOR.
Co-reporter:Xiangheng Niu, Libo Shi, Jianming Pan, Fengxian Qiu, Yongsheng Yan, Hongli Zhao, Minbo Lan
Electrochimica Acta 2016 Volume 199() pp:187-193
Publication Date(Web):1 May 2016
DOI:10.1016/j.electacta.2016.03.100
•Assembly of silver nanoparticles onto SPCE* via vacuum sputtering;•Modulating the surface coverage of silver assemblies via the sputtering time;•The surface coverage affects the H2O2 electroreduction behavior significantly.Nanosized metallic particles are commonly used as an electrode modifier to catalyze various species, yet some of their physico-chemical characters, such as size, morphology, immobilization mode, and modification density, might affect the electrocatalytic properties of these particles. Here we engineer the diverse assemblies of silver nanoparticles on screen-printed carbon electrodes via the versatile vacuum sputtering approach, and evaluate their voltammetric behavior toward hydrogen peroxide reduction in pH 7.4. By simply modulating the sputtering time from 10 s to 200 s, silver assemblies with different surface coverages (defined as the ratio of the particle occupied surface area to the substrate geometric surface area) in the range of 0.38∼0.99 are exquisitely obtained. It is interestingly found that the surface coverage of the assembled silver on the disposable substrate exhibits a significant impact on the voltammetry of hydrogen peroxide electroreduction. The cathodic peak potential keeps shifting positively along with the surface coverage increasing, and the apparent peak current density normalized to the substrate surface area undergoes a volcano-type variation. When the overall peak current is normalized to the metal occupied surface area/loading content, a decreasing tendency of the specific/mass current is observed. These results suggest that the effect of the modification surface coverage should be taken into consideration when evaluating the contribution of nanosized materials to a given electrocatalytic reaction. When an appropriate compromise of the catalytic overpotential and the apparent current as well as the catalyst amount is desired for electrocatalysis, modulation of the modification surface coverage may be utilized to realize this compromise.
Co-reporter:Xiangheng Niu, Yanfang He, Jianming Pan, Xin Li, Fengxian Qiu, Yongsheng Yan, Libo Shi, Hongli Zhao, Minbo Lan
Analytica Chimica Acta 2016 Volume 947() pp:42-49
Publication Date(Web):1 December 2016
DOI:10.1016/j.aca.2016.10.013
•Uncapped nanobranch-based CuS clews with large active surface and abundant sites.•Peroxidase-like activity, with preferable kinetics compared to HRP.•Outstanding performance for the colorimetric sensing of H2O2.•Reliable monitoring of glucose in clinical samples when in couple with GOD.Nanosized materials acting as substitutes of natural enzymes are currently attracting significant research due to their stable enzyme-like characteristics, but some flaws of these nanozymes, including their limited catalytic rate and efficiency, need to be remedied to enable their wider applications. In this work, we verify for the first time the catalytic behavior of uncapped nanobranch-based CuS clews as a peroxidase mimic. XRD, XPS, SEM, and TEM proofs demonstrate that high-purity CuS clews composed of intertwined wires with abundant nanodendrites outside are successfully produced via a facile one-pot hydrothermal synthesis approach, with thiourea as both the sulfion source and the structure-directing agent. The synthesized CuS can catalytically oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to trigger a visible color reaction with rapid response (reaching a maximum change within 5 min). The proposed CuS nanozyme exhibits preferable catalytic kinetics over natural horseradish peroxidase (HRP). This outstanding activity primarily results from the large surface area and rich sites exposed by the uncapped unique structure. Under optimized conditions, the fabricated sensing system provides linear absorbance (652 nm) changes in the H2O2 concentration range of 0.2˜130 μM, with a detection limit of as low as 63 nM. When coupled with glucose oxidase (GOD), the system is demonstrated to be capable of monitoring glucose in blood samples with excellent performance.
Co-reporter:Huihui Yuan, Bin Qian, Wei Zhang, Minbo Lan
Applied Surface Science 2016 Volume 363() pp:483-489
Publication Date(Web):15 February 2016
DOI:10.1016/j.apsusc.2015.12.072
Highlights
- •
Antifouling PVP brushes were successfully grafted on PU films by SI-ATRP.
- •
The effect of polymerization time on surface property and topography was studied.
- •
Hydrophilicity and protein fouling resistance of PVP–PU films were greatly promoted.
- •
Competitive adsorption of three proteins on PVP–PU films was evaluated.
Co-reporter:Lun Song, Li-Min Ma, Qian Sun, Wei-Bing Zhang, Min-Bo Lan, Jun-Hong Qian
Chinese Chemical Letters 2016 Volume 27(Issue 3) pp:330-334
Publication Date(Web):March 2016
DOI:10.1016/j.cclet.2015.12.012
4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-F) was employed as a colorimetric probe for differential detection of biothiols in different media. The spectral response and the selectivity of NBD-F toward thiols were significantly improved by surfactant micelles. Mercapto group exhibited high reactivity in all the solvents (including Tris–HCl buffer solution, CTAB and SDS micelles). The 4-thioether derivatives of NBD-F reacting with Cys and Hcy but not GSH could transfer to the corresponding 4-amino-substituents via intramolecular nucleophilic aromatic substitution, thus, GSH could be discriminated from Cys/Hcy. In CTAB micelles, the reaction product of NBD-F with Cys is non-fluorescent and it absorbs in long-wavelength region. According to the spectral responses of NBD-F toward different low-molecular-weight thiols, we could identify Cys, Hcy and GSH from each other.4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-F) was employed as a probe to distinguish biothiols from each other. The spectral response and the selectivity of NBD-F toward thiols were dramatically improved by surfactant micelles.
Co-reporter:X. H. Niu, L. B. Shi, H. L. Zhao and M. B. Lan
Analytical Methods 2016 vol. 8(Issue 8) pp:1755-1764
Publication Date(Web):13 Jan 2016
DOI:10.1039/C5AY03181H
Enormous demands for blood sugar management, food and pharmaceutical quality control, bioprocess monitoring, and environmental pollution inspection have encouraged the fabrication of high-performance sensing platforms for the detection of glucose in various matrices. In comparison with traditional enzyme-based analytical devices, nonenzymatic electrochemical glucose sensors have attracted special interest and the attention of analysts in the past decade due to their unique advantages; however, the underlying drawbacks of detection performance still seriously restrict their commercial development and large-scale application. This minireview clarifies the intrinsic bottlenecks of glucose amperometric analysis on Pt-based enzymeless interfaces, and emphasis is placed on discussing the advanced strategies utilized to enhance the analytical properties of Pt-based enzyme-free electrochemical glucose sensors.
Co-reporter:Xiang Zhu;Hongli Zhao;Xiangheng Niu;Tingting Liu;Libo Shi
Microchimica Acta 2016 Volume 183( Issue 8) pp:2431-2439
Publication Date(Web):2016 August
DOI:10.1007/s00604-016-1887-3
Three ferrites of type MFe2O4 (where M is bivalent Fe, Co or Mn) dispersed on multi-walled carbon nanotubes (MWCNTs) were prepared by a coprecipitation method. Their electrocatalytic properties toward the reduction of H2O2 at pH 7.4 were systematically compared. Catalytic reduction rates at an applied potential of −0.4 V (vs. Ag/AgCl) and pseudo Michaelis-Menten constants show the electrocatalytic ability to follows the order Fe3O4 > CoFe2O4 > MnFe2O4. This diversity is attributed to the differences in the M(II) used and its occupancy on the lattice surface. The sensitivities are 120.98 ± 0.15, 48.45 ± 0.23 and 32.25 ± 0.27 μA cm−2 mM−1, and the limits of detection are 0.98, 2.59 and 5.64 μM of H2O2 (at an S/N ratio of 3).
Co-reporter:Libo Shi, Xiang Zhu, Tingting Liu, Hongli Zhao, Minbo Lan
Sensors and Actuators B: Chemical 2016 Volume 227() pp:583-590
Publication Date(Web):May 2016
DOI:10.1016/j.snb.2015.12.092
•Encapsulating Cu nanoparticles (NPs) in zeolitic imidazolate framework 8 (ZIF-8).•ZIF-8 as host to restrict and stabilize Cu NPs.•Possessing higher electrocatalytic performance than the structure of Cu NPs loaded on ZIF-8.•Exhibiting impressive stability for glucose sensing due to ZIF-8-encapuslated structure.In this work, we applied metal-organic frameworks (MOFs) as a porous matrix to encapsulate Cu nanoparticles (NPs) for nonenzymatic glucose sensing in alkaline media. SEM and TEM confirmed that the size of the encapsulated Cu NPs ranges from 2.5 to 5 nm. The hybrid of Cu NPs encapsulated in ZIF-8 (Cu-in-ZIF-8) was further modified onto screen-printed electrodes for nonenzymatic sensing of glucose in alkaline medium. The porous structure of ZIF-8 are beneficial for the unimpeded diffusion of glucose and reaction product. And as a matrix for encapsulating Cu NPs, ZIF-8 also protect the Cu NPs from dissolution and agglomeration during the electrocatalytic process. For comparison, the electrochemical performance of Cu NPs loaded on ZIF-8 (Cu-on-ZIF-8) was also investigated and it is found that Cu-in-ZIF-8 exhibited higher activity and better stability for cyclic test toward the oxidation of glucose in alkaline media. Additionally, Cu-in-ZIF-8 based glucose sensor also shows a favorable sensitivity and selectivity.Cu nanoparticles are stably encapsulated in ZIF-8 for nonenzymatic glucose sensing in alkaline media.
Co-reporter:Xiang Zhu, Tingting Liu, Hongli Zhao, Libo Shi, Xiaoqing Li, Minbo Lan
Biosensors and Bioelectronics 2016 Volume 79() pp:449-456
Publication Date(Web):15 May 2016
DOI:10.1016/j.bios.2015.12.061
•A captivating porous Pt–Pd interface for the immobilization of SOD.•Ultrahigh sensitive and selective sensing of O2∙−.•Capturing the trace level of O2∙− released from stimulated cells.Considering the critical roles of superoxide anion (O2∙−) in pathological conditions, it is of great urgency to establish a reliable and durable approach for real-time determination of O2∙−. In this study, we propose a porous Pt–Pd decorated superoxide dismutase (SOD) sensor for qualitative and quantitative detection O2∙−. The developed biosensor exhibits a fast, selective and linear amperometric response upon O2∙− in the concentration scope of 16 to 1536 μM (R2=0.9941), with a detection limit of 0.13 μM (S/N=3) and a low Michaelis–Menten constant of 1.37 μM which indicating a high enzymatic activity and affinity to O2∙−. Inspiringly, the proposed sensor possesses an ultrahigh sensitivity of 1270 μA mM−1 cm−2. In addition, SOD/porous Pt–Pd sensor exhibits excellent anti-interference property, reproducibility and long-term storage stability. Beyond our expectation, the trace level of O2∙− released from living cells has also been successfully captured. These satisfactory results are mainly ascribed to (1) the porous interface with larger surface area and more active sites to provide a biocompatible environment for SOD (2) the specific biocatalysis of SOD towards O2∙− and (3) porous Pt–Pd nanomaterials fastening the electron transfer. The superior electrochemical performance makes SOD/porous Pt–Pd sensor a promising candidate for monitoring the dynamic changes of O2∙−in vivo.
Co-reporter:Xiangheng Niu, Jianming Pan, Fengxian Qiu, Xin Li, Yongsheng Yan, Libo Shi, Hongli Zhao, Minbo Lan
Talanta 2016 Volume 161() pp:615-622
Publication Date(Web):1 December 2016
DOI:10.1016/j.talanta.2016.09.024
•Anneal-shrinked Cu2O dendrites grown on Cu foam for nonenzymatic glucose sensing.•The facile anneal and the compatibility of Cu2O and Cu lead to a robust interface.•The porosity of Cu2O-decorated Cu foam provides large active surface.•Excellent stability and ultrahigh sensitivity for glucose detection.Enzyme-free electrochemical detection of glucose in alkaline media with favorable properties has been acquired by fabricating a robust and large-surface sensing platform, which is composed of anneal-shrinked Cu2O dendrites grown on porous Cu foam. On the one hand, the good compatibility of electrodeposited Cu2O architectures and Cu foam substrate, together with a post-deposition anneal at 200 °C, offers a mechanically stable interface for glucose determination. On the other hand, the macropores of Cu foam that is decorated with unique Cu2O dendrites provide large active surface for electrocatalytic reaction and mass transport. As a result, selective sensing of glucose in the linear concentration range of 0.001–1.4 mM was achieved on the fabricated sensor, with a sensitivity of as high as 5.04 mA cm−2 mM−1 and a detection limit of 0.13 μM. Desired long-term performance stability was obtained, partially due to the strong adhesion of Cu2O microstructures to the Cu foam support after annealing. Practical monitoring of glucose in serum samples was also demonstrated on the proposed sensor.
Co-reporter:Yangliao Hu, Xiangheng Niu, Hongli Zhao, Jie Tang, Minbo Lan
Electrochimica Acta 2015 Volume 165() pp:383-389
Publication Date(Web):20 May 2015
DOI:10.1016/j.electacta.2015.03.036
•Macroporous Cu foams with large surface were assembled by electrodeposition assisted with hydrogen evolution.•The synthesized Cu was substituted by metallic Pt through facile galvanic replacement, forming Pt monolayer-support alloy structures with highly catalytic activity.•The electrochemical oxidation behavior of glucose on this interface was investigated.•Favorable properties for nonenzymatic glucose detection were obtained at the proposed sensor based on Pt-placed Cu frameworks.With respect to a nonenzymatic electrochemical sensor for detection of small biomolecules like glucose, it is well recognized that an interface with highly electrocatalytic properties is desired. Our previous studies have demonstrated that porous Cu foams from hydrogen evolution assisted electrodeposition could provide beneficial structures for large active surface and mass transfer in glucose sensing (Biosens. Bioelectron., 2014, 51: 22-28), and decoration of micro-scale Pt cubes on this multiaperture substrate through manipulative deposition offered exciting activity and stability for electro-catalyzing glucose in neutral media (Chem. Eur. J., 2013, 19: 9534-9541). On the basis of these results here we further cover the porous Cu frameworks with a Pt monolayer through the galvanic replacement reaction, and fabricate a new electrochemical interface for high-performance determination of glucose. The sensing surface was facilely assembled by firstly electrodepositing porous Cu architectures with hydrogen evolution and then galvanically replacing the surface layer with Pt, and was well characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and energy dispersive spectroscopy. It was found that the unilaminar Pt-replaced Cu frameworks, with the profitable reaction surface derived from porous skeletons and the underlying activity of Pt-support composites, could supply the highly electrocatalytic oxidation of glucose in phosphate buffer solution (pH 7.4). As a result, the prepared enzymeless sensor provided linear amperometric responses for glucose in the concentration scope of 1∼11 mM, with a high sensitivity of 9.62 μA cm−2 mM−1.
Co-reporter:Xiangheng Niu, Hongli Zhao, Minbo Lan, Liang Zhou
Electrochimica Acta 2015 Volume 151() pp:326-331
Publication Date(Web):1 January 2015
DOI:10.1016/j.electacta.2014.11.024
•Synthesis of Pt NPs dispersedly encapsulated in carbon microspheres.•Reduced glutathione (R-GSH) as the capping agent and reductant simultaneously.•Showing high electrocatalytic activity for glucose oxidation in neutral media.•Possessing attractive stability of performance due to the carbon-encapsulated structure.Electro-oxidizing glucose effectively is well known as the critical point in developing analytical sensors and carbohydrate-based fuel cells. Here we prepared a new electrode material, platinum nanoparticles encapsulated in carbon microspheres (Pt/GSH), to promote the glucose electrocatalytic oxidation reaction in neutral media. The Pt/GSH composite was synthesized by using a simple hydrothermal method, with reduced glutathione (R-GSH) as the capping agent and reductant simultaneously, followed by a calcination process. It was found that the obtained Pt particles with a mean size of 26.8 nm were well dispersed in the interconnected carbon microspheres, providing a stable and efficient catalytic platform for glucose electro-oxidation. As a result, the synthesized catalyst exhibited higher activity for electro-catalyzing glucose compared to commercial Pt black and Pt/C catalysts, with a mass activity of 15.4 μA μg−1Pt, approximately 13 times of Pt black and 2.1 times of Pt/C. Besides, due to the decreased dissolution and agglomeration of Pt NPs in the carbon-encapsulated structure, the Pt/GSH catalyst kept quite stable activity upon reuse even in the presence of chloride ions.
Co-reporter:Qianying Sheng, Kaiya Yang, Xingya Xue, Xiuling Li, Zhimou Guo, Aijin Shen, Yanxiong Ke, Minbo Lan, Xinmiao Liang
Journal of Chromatography A 2015 Volume 1413() pp:47-59
Publication Date(Web):25 September 2015
DOI:10.1016/j.chroma.2015.08.018
•A zwitterionic material Click TE-Cys was applied in phosphopeptides enrichment.•Mixed-mode retention mechanisms between phosphopeptides and material were revealed.•Singly- and multiply-phosphorylated peptides were well divided into two fractions.•It exhibited high enrichment selectivity for multiply-phosphorylated peptides.An interesting and novel method for the selective and sequential enrichment of singly- and multiply-phosphorylated peptides with a zwitterionic material “Click TE-Cys” is presented. Retention mechanisms between phosphopeptides and Click TE-Cys are systematically investigated by checking the influence of acetonitrile content, pH value, and buffer concentration on the retention of phosphopeptides. Both hydrophilic interaction and electrostatic interaction are involved in retention between phosphopeptides and Click TE-Cys. Based on these results, an optimized method is established for selective enrichment of phosphopeptides using Click TE-Cys. This method not only exhibits high selectivity for phosphopeptides, but also fractionates singly- and multiply-phosphorylated peptides into two fractions. This method was evaluated using relatively complex samples, including peptide mixtures of α-casein and bovine serum albumin (BSA) at a molar ratio of 1:10 and skim milk. This efficient and optimized protocol has great potential for enriching multiply-phosphorylated peptides and could be a valuable tool for specific enrichment of phosphopeptides in phosphoproteome analysis.
Co-reporter:Hongli Zhao, Zongyan Chen, Liang Tao, Xiang Zhu, Minbo Lan and Zhen Li
RSC Advances 2015 vol. 5(Issue 84) pp:68454-68460
Publication Date(Web):06 Aug 2015
DOI:10.1039/C5RA11013K
As ferrite nanoparticles (MFe2O4) have been widely used in biomedical field, their safety evaluation has been paid great attention both in vitro and in vivo. In this paper, the ultra-small MFe2O4 (M = Fe, Mn, Co) nanoparticles with the average size less than 5 nm were prepared by thermal decomposition method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and vibrating sample magnetometry (VSM). The toxic effect on human lung epithelial A549 cells treated with MFe2O4 nanoparticles at the different concentrations was evaluated in vitro. Mitochondrial function (MTT assay), cellular morphology, reactive oxygen species (ROS), superoxide dismutase (SOD), membrane lipid peroxidation (LPO) and glutathione (GSH) were assessed as toxicity end points. The results showed that the cytotoxicity of ultra-small MFe2O4 nanoparticles was in a dose- and time-dependent manner. Moreover, ultra-small Fe3O4 nanoparticles were found to be nearly non-toxic in A549 cells, while MnFe2O4 nanoparticles exhibited cytotoxic effects, and CoFe2O4 nanoparticles exerted higher cytotoxic effects among the three studied particles at the same concentration.
Co-reporter:Xiang Zhu, Xiangheng Niu, Hongli Zhao, Jie Tang, Minbo Lan
Biosensors and Bioelectronics 2015 Volume 67() pp:79-85
Publication Date(Web):15 May 2015
DOI:10.1016/j.bios.2014.07.004
•A captivating electrochemical sensing interface for the immobilization of SOD.•Pt–Pd/MWCNTs promote the electron transfer and provide enhanced performance for O2∙− sensing.•Outstanding sensitivity and excellent selectivity for O2∙− determination.Monitoring of reactive oxygen species like superoxide anion (O2∙−) turns to be of increasing significance considering their potential damages to organism. In the present work, we fabricated a novel O2∙− electrochemical sensor through immobilizing superoxide dismutase (SOD) onto a Pt–Pd/MWCNTs hybrid modified electrode surface. The Pt–Pd/MWCNTs hybrid was synthesized via a facile one-step alcohol-reduction process, and well characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The immobilization of SOD was accomplished using a simple drop-casting method, and the performance of the assembled enzyme-based sensor for O2∙− detection was systematically investigated by several electrochemcial techniques. Thanks to the specific biocatalysis of SOD towards O2∙− and the Pt–Pd/MWCNTs – promoted fast electron transfer at the fabricated interface, the developed biosensor exhibits a fast, selective and linear amperometric response upon O2∙− in the concentration scope of 40–1550 μM (R2=0.9941), with a sensitivity of 0.601 mA cm−2 mM−1 and a detection limit of 0.71 μM (S/N=3). In addition, the favorable biocompatibility of this electrode interface endows the prepared biosensor with excellent long-term stability (a sensitivity loss of only 3% over a period of 30 days). It is promising that the proposed sensor will be utilized as an effective tool to quantitatively monitor the dynamic changes of O2∙− in biological systems.
Co-reporter:Jie Tang, Xiang Zhu, Xiangheng Niu, Tingting Liu, Hongli Zhao, Minbo Lan
Talanta 2015 Volume 137() pp:18-24
Publication Date(Web):15 May 2015
DOI:10.1016/j.talanta.2015.01.009
•Polymerization of dopamine leads to reduction of graphene oxide: a green chemistry method.•A captivating electrochemical sensing interface for the immobilization of enzyme like SOD.•PtPd-PDARGO promote the electron transfer and provide enhanced performance for O2●− sensing.•Outstanding sensitivity and excellent selectivity for O2●− determination.In the present work, a high-performance enzyme-based electrochemical sensor for the detection of superoxide anion radical (O2●−) is reported. Firstly, we employed a facile approach to synthesize PtPd nanoparticles (PtPd NPs) on chemically reduced graphene oxide (RGO) coated with polydopamine (PDA). The prepared PtPd-PDARGO composite was well characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. Then the assembled composite was used as a desired electrochemcial interface for superoxide dismutase (SOD) immobilization. Owing to the PDA layer as well as the synergistic effect of PtPd NPs, the fabricated SOD/PtPd-PDARGO sensor exhibited an outstanding sensitivity of 909.7 μA mM−1 cm−2 upon O2●− in a linear range from 0.016 mM to 0.24 mM (R2=0.992), with a low detection limit of 2 μM (S/N=3) and excellent selectivity, good reproducibility as well as favorable long-term stability.
Co-reporter:Libo Shi;Xiangheng Niu;Tingting Liu;Hongli Zhao;Minbo Lan
Microchimica Acta 2015 Volume 182( Issue 15-16) pp:2485-2493
Publication Date(Web):2015 November
DOI:10.1007/s00604-015-1605-6
We have synthesized nitrogen-doped graphene nanoribbons (N-GrNRs) by unzipping multi-walled carbon nanotubes (CNTs) under strongly oxidizing conditions and subsequent doping with nitrogen by a low-temperature hydrothermal method. The N-GNRs were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy, and assembled on a disposable screen-printed carbon electrode to give a sensor for H2O2 that was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, chronocoulometry and chronoamperometry. The nano-modified electrode displays enhanced electron transfer ability, and has a large active surface and a large number of catalytically active sites that originate from the presence of nitrogen atoms. This results in a catalytic activity towards H2O2 reduction at near-neutral pH values that is distinctly improved compared to electrodes modified with CNTs or unzipped (non-doped) CNTs only. At a working potential of −0.4 V (vs. Ag/AgCl), the amperometric responses to H2O2 cover the 5 to 2785 μM concentration range, with a limit of detection as low as 1.72 μM. This enzyme-free electrochemical sensor exhibits outstanding selectivity and long-term stability for H2O2 detection.
Co-reporter:Xueling Zhao, Zongyan Chen, Hongli Zhao, Denghao Zhang, Liang Tao and Minbo Lan
RSC Advances 2014 vol. 4(Issue 107) pp:62153-62159
Publication Date(Web):31 Oct 2014
DOI:10.1039/C4RA10801A
Cancer theranostics, the ability to simultaneously diagnose and treat cancer, has become one of the major driving forces in nanobiotechnology. In the present work, a multifunctional system, methylene blue-incorporated folate-functionalized Fe3O4/mesoporous silica core–shell magnetic nanoparticles (MNPs), for simultaneous near-infrared (NIR) fluorescence imaging and targeting photodynamic therapy (PDT) has been developed. The core Fe3O4 MNPs offers the function of magnetically guided drug delivery, the mesoporous silica shell acts as an efficient drug loaded carrier, the photosensitizer methylene blue (MB) exhibits excellent NIR fluorescence imaging and PDT efficiency, and the folic acid (FA) can effectively enhance the delivery of MB to the targeting cancer cells, which overexpress the folate receptor. The results indicated that the multifunctional system could effectively be used in NIR fluorescence imaging. Moreover, it exhibited a synergistic effect of magnetic targeted PDT of cancer under NIR laser irradiation. Thus, the multifunctional system is promising for simultaneous cancer diagnosis and therapy.
Co-reporter:Xiang Zhu, Xiangheng Niu, Hongli Zhao, Minbo Lan
Sensors and Actuators B: Chemical 2014 195() pp: 274-280
Publication Date(Web):
DOI:10.1016/j.snb.2014.01.052
Co-reporter:Xiangheng Niu, Yuxiu Li, Jie Tang, Yangliao Hu, Hongli Zhao, Minbo Lan
Biosensors and Bioelectronics 2014 Volume 51() pp:22-28
Publication Date(Web):15 January 2014
DOI:10.1016/j.bios.2013.07.032
•Porous Cu foam with tunable porosity.•As an electrochemical interface for enzymeless glucose sensing.•Showing high electrocatalytic activity for glucose oxidation in alkaline media.•Exhibiting good sensitivity and excellent selectivity for glucose detection.•Possessing attractive durability of performance thanks to robust architectures.It is widely thought in electro-biochemical analysis that the sensing interfaces play a key role in the enzymeless detection of biomolecules like glucose, ascorbic acid, dopamine and uric acid. On the way to maximize the anti-poisoning sensitivity of nonenzymatic electrochemical glucose sensors as well as achieve favorable selectivity, we propose here a porous interface fabricated by a facile but effective approach for glucose monitoring in alkaline media containing dissolved oxygen. The sensing interface based on porous Cu foams is directly formed on a homemade disposable screen-printed carbon electrode (SPCE) substrate by electrodeposition assisted with hydrogen evolution simultaneously, and its porosity can be easily tailored through adjusting deposition conditions for the optimal electrocatalytic oxidation of glucose molecules. SEM and BET studies show that the generated Cu foam possesses robust hierarchical porous architectures with greatly enhanced surface area and pore volume, beneficial for the unimpeded mobility of glucose and reaction products. Cyclic voltammetric tests indicate that a diffusion-controlled glucose electro-oxidation reaction occurs at the Cu foam electrode at around +0.35 V vs. Ag/AgCl in 0.1 M NaOH. Chronoamperometric results obtained under optimized conditions reveal that the proposed sensor exhibits desired poison resistance ability in the presence of chloride ions and significant selectivity to glucose, providing fascinating sensitivities of 2.57 and 1.81 mA cm−2 mM−1 for glucose in the linear concentration ranges of 2–80 μM and 0.1–5 mM, respectively. The limit of detection is calculated to be as low as 0.98 μM according to the signal-to-noise ratio of three. In addition, the fabricated sensing interface shows attractive reproducibility (RSD of 5.1% and 7.0% for 15 repeated measurements on a sensor and for measurements on 15 prepared sensors, respectively) and outstanding long-term stability (less than 5% loss in sensitivity over 1 month) for glucose detection. The application of the Cu foam based sensor for monitoring glucose in practical samples is also successfully demonstrated.
Co-reporter:Xiangheng Niu, Minbo Lan, Hongli Zhao, and Chen Chen
Analytical Chemistry 2013 Volume 85(Issue 7) pp:3561
Publication Date(Web):March 4, 2013
DOI:10.1021/ac3030976
Highly sensitive and selective nonenzymatic detection of glucose has been achieved using a novel disposable electrochemical sensor based on three-dimensional (3D) porous nickel nanostructures. The enzyme-free sensor was fabricated through in situ growing porous nickel networks on a homemade screen-printed carbon electrode substrate via electrochemically reducing the Ni2+ precursor, along with continuously liberating hydrogen bubbles. The resulting nickel-modified electrode was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), powder X-ray diffractometry (XRD), and electrochemical techniques. Cyclic voltammetric, alternating-current impedance, and amperometric methods were used to investigate the catalytic properties of the assembled sensor for glucose electro-oxidation in alkaline media. Under optimized conditions, the enzymeless sensor exhibited excellent performance for glucose analysis selectively, offering a much wider linear range (from 0.5 μM to 4 mM), an extremely low detection limit (0.07 μM, signal-to-noise ratio (S/N) of 3), and an ultrahigh sensitivity of 2.9 mA/(cm2 mM). Importantly, favorable reproducibility and long-term performance stability were obtained thanks to the robust frameworks. Application of the proposed sensor in monitoring blood glucose was also demonstrated.
Co-reporter:Dr. Xiangheng Niu;Dr. Hongli Zhao;Dr. Chen Chen;Dr. Minbo Lan
ChemCatChem 2013 Volume 5( Issue 6) pp:1416-1425
Publication Date(Web):
DOI:10.1002/cctc.201200658
Abstract
Improving the electrocatalytic activity of Pt-based catalysts is of great importance for the development of heterogeneous catalysis, fuel cells, and analytical sensors. Herein, we achieve significant enhancement of the catalytic activity of Pt–Pd bimetallic materials towards glucose electrooxidation by introducing porous architectures with three-dimensional dendritic microstructures, which were fabricated in situ on desired substrates through electrochemically reducing precursors along with periodic bubbling caused by the intermittent liberation of hydrogen. The synthesized Pt–Pd materials were characterized by SEM, nitrogen adsorption/desorption, energy dispersive spectroscopy, XRD, inductively coupled plasma optical emission spectrometry, and electrochemical techniques. Encouragingly, an extra-large active surface area of up to 80.8 m2 g−1 was obtained for the porous Pt–Pd nanostructures, almost 3.8 times that of the Pt–Pd alloys prepared by standard electrodeposition techniques. As a result, the synthesized Pt–Pd with porous frameworks exhibited remarkably improved electrocatalytic properties for glucose oxidation in neutral media, with 1.5 times the mass activity compared to the conventional Pt–Pd structure. In addition, the porous Pt–Pd catalysts could be reused at least 100 times in the presence of chloride ions, with negligible loss of activity.
Co-reporter:Dr. Xiangheng Niu;Dr. Minbo Lan;Dr. Hongli Zhao;Dr. Chen Chen
Chemistry - A European Journal 2013 Volume 19( Issue 29) pp:9534-9541
Publication Date(Web):
DOI:10.1002/chem.201300234
Abstract
The investigation of highly efficient catalysts for the electrochemical oxidation of glucose is the most critical challenge to commercialize nonenzymatic glucose sensors, which display a few attractive superiorities including the sufficient stability of their properties and the desired reproducibility of results over enzyme electrodes. Herein we propose a new and very promising catalyst: Pt cubes well-dispersed on the porous Cu foam, for the the electrochemical oxidation reaction of glucose in neutral media. The catalyst is fabricated in situ on a homemade screen-printed carbon electrode (SPCE) substrate through initially synthesizing the three-dimensional (3D) porous Cu foam using a hydrogen evolution assisted electrodeposition strategy, followed by electrochemically reducing the platinic precursor simply and conveniently. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) proofs demonstrate that Pt cubes, with an average size (the distance of opposite faces) of 185.1 nm, highly dispersed on the macro/nanopore integrated Cu foam support can be reproducibly obtained. The results of electrochemical tests indicate that the cubic Pt-based catalyst exhibits significant enhancement on the catalytic activity towards the electrooxidation of glucose in the presence of chloride ions, providing a specific activity 6.7 times and a mass activity 5.3 times those of commercial Pt/C catalysts at −0.4 V (vs. Ag/AgCl). In addition, the proposed catalyst shows excellent stability of performance, with only a 2.8 % loss of electrocatalytic activity after 100 repetitive measurements.
Co-reporter:Xiangheng Niu, Chen Chen, Hongli Zhao, Jie Tang, Yuxiu Li, Minbo Lan
Electrochemistry Communications 2012 Volume 22() pp:170-173
Publication Date(Web):August 2012
DOI:10.1016/j.elecom.2012.06.020
A new screen-printed carbon electrode with porous architectures prepared using an extremely facile and low-cost approach is introduced. The preparation mainly involved a printing procedure of a graphite-based layer doped with CaCO3 powders and a subsequent dissolution of these powders. The resulting porous screen-printed carbon electrode (P-SPCE) can offer large surface, broad potential window, low background current and high electrochemical reactivity. Moreover, the proposed P-SPCE provides enhanced performance for enzyme-free H2O2 sensing compared to conventional glassy carbon electrodes and screen-printed carbon electrodes. These attractive properties of the P-SPCE are expected to be of wider applications.Highlights► CaCO3 powder doped graphite-based ink. ► Porous screen-printed carbon electrode. ► Wide potential window, low background current and high electrochemical reactivity. ► Enhanced performance for nonenzymatic H2O2 sensing.
Co-reporter:Xiangheng Niu, Hongli Zhao, Chen Chen, Minbo Lan
Electrochimica Acta 2012 Volume 65() pp:97-103
Publication Date(Web):30 March 2012
DOI:10.1016/j.electacta.2012.01.030
In the present study the electrocatalytic behavior of platinum nanoparticle-decorated multi-walled carbon nanotube clusters vertically aligned on a screen-printed gold nanofilm electrode substrate (SPGFE/MWCNTC/PtNP) toward hydrogen peroxide was intensively investigated. Oriented multi-walled carbon nanotube clusters (MWCNTC) were firstly well-organized onto the screen-printed gold film electrode (SPGFE) surface by covalent immobilization, and then platinum nanoparticles (PtNPs) dispersed on the MWCNTC structure were in situ synthesized by electrochemically reducing chloroplatinic acid. It was demonstrated that the MWCNTC/PtNP hybrid structure on the SPGFE substrate could significantly enhance the electrochemical reduction of hydrogen peroxide in neutral solutions. Compared with platinum nanoparticles loading on disordered multi-walled carbon nanotubes (SPGFE/MWCNT/PtNP), the proposed SPGFE/MWCNTC/PtNP exhibited more sensitive responses for hydrogen peroxide reduction. The fabricated electrode provided linear current responses for hydrogen peroxide in the concentration range from 5 to 2000 μM with a detection limit of 1.23 μM. The non-enzymatic sensor also offered good reproducibility and high selectivity for hydrogen peroxide detection. The carbon nanotube cluster/platinum nanoparticle hybrid system holds great promise as a scaffold to fabricate enzyme biosensors.Highlights► MWCNTC were vertically immobilized on the SPGFE surface by self-assembly. ► MWCNTC were then decorated with well-dispersed PtNP. ► SPGFE/MWCNTC/PtNP could significantly enhance the electrocatalytic reduction of H2O2. ► SPGFE/MWCNTC/PtNP exhibited higher sensitivity and excellent selectivity. ► The fabricated electrode holds great promise to develop novel enzyme biosensors.
Co-reporter:Siyuan Li, Chunying Guo, Xianqiang Sun, Yaozong Li, Hongli Zhao, Dongmei Zhan, Minbo Lan, Yun Tang
European Journal of Medicinal Chemistry 2012 Volume 49() pp:271-278
Publication Date(Web):March 2012
DOI:10.1016/j.ejmech.2012.01.021
4-anilinoquinazoline and 4-anilinoquinoline scaffolds bearing a 2,2,6,6-tetramethylpiperidine-N-oxyl(TEMPO) have been synthesized and evaluated for their ability to inhibit EGFR tyrosine kinase and A431 cell lines. Compared to their corresponding parent compounds, all of the new compounds bearing a TEMPO showed more efficient inhibition for EGFR and A431 cells. Furthermore, we have proved that these molecules bearing a TEMPO can exactly get into A431 cells exerting inhibitory effect that may be used for EPR detecting. In our docking model, quinazolines bearing a TEMPO on either 6- or 3-positions took different linking modes according to EGFR crystal structure. In contrast to their parent compounds, these new TEMPO-derived analogues possessed compatible inhibitory effect that might be useful as potential EGFR inhibitors and as EPR bio-probes.Highlights► 4-anilinoquinazoline and 4-anilinoquinoline bearing a TEMPO were synthesized. ► These compounds showed inhibitory activity on EGFR kinase and A431 cells. ► These compounds might be useful as EPR bio-probes. ► Docking studies were carried out.
Co-reporter:Limin Ma, Junhong Qian, Haiyu Tian, Minbo Lan and Weibing Zhang
Analyst 2012 vol. 137(Issue 21) pp:5046-5050
Publication Date(Web):28 Aug 2012
DOI:10.1039/C2AN35624D
4-Nitro-1,8-naphthalic anhydride (NNA) was used to distinguish cysteine from homocysteine and other potentially interfering thiols through a novel sequential substitution mechanism. The discrimination involves a blue-fluorescent thioether formation via nucleophilic aromatic substitution of the nitro group by thiol, followed by a second intramolecular nucleophilic aromatic substitution of alkylthio with the amino group to give the green-fluorescent 4-amino derivative. NNA is highly selective towards Cys, and the detection limit of Cys by this method is 0.3 μM.
Co-reporter:Siyuan Li, Chunying Guo, Hongli Zhao, Yun Tang, Minbo Lan
Bioorganic & Medicinal Chemistry 2012 Volume 20(Issue 2) pp:877-885
Publication Date(Web):15 January 2012
DOI:10.1016/j.bmc.2011.11.056
Co-reporter:Siyuan Li, Xianqiang Sun, Hongli Zhao, Yun Tang, Minbo Lan
Bioorganic & Medicinal Chemistry Letters 2012 Volume 22(Issue 12) pp:4004-4009
Publication Date(Web):15 June 2012
DOI:10.1016/j.bmcl.2012.04.092
By using of structure-based virtual screening, 13 novel epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors were discovered from 197,116 compounds in the SPECS database here. Among them, 8 compounds significantly inhibited EGFR kinase activity with IC50 values lower than 10 μM. 3-{[1-(3-Chloro-4-fluorophenyl)-3,5-dioxo-4-pyrazolidinylidene]methyl}phenyl 2-thiophenecarboxylate (13), particularly, was the most potent inhibitor possessing the IC50 value of 3.5 μM. The docking studies also provide some useful information that the docking models of the 13 compounds are beneficial to find a new path for designing novel EGFR inhibitors.By using of structure-based virtual screening, 13 novel epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors were hit from SPECS database.
Co-reporter:Xiangheng Niu, Chen Chen, Hongli Zhao, Yan Chai, Minbo Lan
Biosensors and Bioelectronics 2012 Volume 36(Issue 1) pp:262-266
Publication Date(Web):June–July 2012
DOI:10.1016/j.bios.2012.03.030
Novel snowflake-like Pt–Pd bimetallic nanoclusters (Pt–PdBNC) were synthesized on a screen-printed gold nanofilm electrode (SPGFE) substrate by electrochemically reducing precursors with a new constant potential/multi-potential step deposition strategy. The electrocatalytic behavior of the modified electrode (SPGFE/Pt–PdBNC) towards H2O2 was investigated. The results indicate that the as-prepared Pt–PdBNC significantly enhances the electrochemical reduction of H2O2 in neutral media, exhibiting preferable electrocatalytic performance compared to Pt and Pd monometallic nanoclusters. Under optimum conditions, SPGFE/Pt–PdBNC offers linear responses for H2O2 in the concentration range from 0.005 to 6 mM with an ultrahigh sensitivity of 804 mA M−1 cm−2 and excellent selectivity. Furthermore, glucose oxidase was immobilized on the Pt–PdBNC structure, and the fabricated biosensor presents favorable properties for glucose sensing.Highlights► Novel 3D Pt–Pd bimetallic nanoclusters (Pt–PdBNC) on a gold nanofilm substrate. ► as-prepared SPGFE/Pt–PdBNC significantly enhances the reduction of H2O2. ► Enzyme-free sensor exhibits ultrahigh sensitivity for H2O2 detection. ► Fabricated GOx biosensor shows favorable performance for glucose sensing.
Co-reporter:Xiangheng Niu, Hongli Zhao, Minbo Lan
Electrochimica Acta 2011 Volume 56(Issue 27) pp:9921-9925
Publication Date(Web):30 November 2011
DOI:10.1016/j.electacta.2011.08.057
In this paper, two disposable screen-printed antimony film electrodes (SPSbFEs) modified with multi-walled carbon nanotubes (MWCNTs) and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), respectively for electrochemical stripping measurement are introduced. The modified screen-printed electrode substrate was prepared by homogeneously doping the attractive material into the graphite-based printing ink, and then an antimony film was in situ formed by simultaneously electrodepositing the antimony precursor with interesting analytes on the modified substrate. The electroanalytical performance of the modified SPSbFE for heavy metals based on the anodic stripping protocol was intensively evaluated. It was found that stripping voltammetric measurements of mercury (II) and lead (II) at the modified SPSbFEs resulted in good peaks with very low background contribution. In comparison with the bare SPSbFE, the modifications of both MWCNTs and [Bmim]BF4 were demonstrated providing more sensitive responses. The results indicated that the SPSbFE modified with 4 wt% [Bmim]BF4 exhibited well linear behavior in the mercury (II) concentration range from 20 to 140 μg/L (R2 = 0.998) with a detection limit of 0.36 μg/L (S/N = 3) under a 120 s accumulation, and good repeatability with a relative standard deviation (RSD) of 4.16% (40 μg/L, n = 12). The proposed electrodes, as new styles of “mercury-free” electrodes, also exhibit encouraging properties for measurements of practical samples.Highlights► We developed disposable screen-printed antimony film electrodes modified with MWCNTs and IL. ► The proposed electrodes provided well-define signals with very low background for heavy metals. ► We demonstrated that the modified SPSbFE could provide more sensitive responses than the bare one. ► This greatly expands the scope to conveniently develop ultrasensitive antimony electrodes.
Co-reporter:Ronghua Yu, Hongli Zhao, Zijun Zhao, Yuanyuan Wan, Huihui Yuan, Minbo Lan, Leonard F. Lindoy, Gang Wei
Journal of Colloid and Interface Science 2011 Volume 362(Issue 2) pp:584-593
Publication Date(Web):15 October 2011
DOI:10.1016/j.jcis.2011.06.079
The fabrication of a new amphiphilic block copolymer composed of a poly dl-lactic acid (PLA) hydrophobic backbone and pH dependent thermo-sensitive poly (N-isopropyl) methacrylamide-co-N-isopropylmaleamic acid-co-10-undecenoic acid (PNIPAAm-co-NIPMMA-co-UA) entities as hydrophilic domains as well as carrying 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) residues for electron spin resonance (ESR) labeling is reported. The lower critical solution temperature (LCST) of the copolymer was determined by optical absorbance measurements. The LCST was pH dependent and varied in a narrow practical range, 35.4 °C at pH 5.0, 37.5 °C at pH 6.5 and 39.4 °C at pH 7.4, which was below, near and above nominal physiological temperature respectively. The assembly of the copolymer into micelles in aqueous solution at temperatures below the LCST was confirmed by FT-IR, 1H NMR and fluorescence spectroscopy. It is demonstrated that the anticancer drug, 5-fluorouracil (5-FU) can be loaded effectively within the polymeric micelles and released in response to environmental stimuli- namely, pH and temperature.Graphical abstractThe LCST was pH dependent and varied in a narrow practical range, 35.4 °C at pH 5.0, 37.5 °C at pH 6.5 and 39.4 °C at pH 7.4, which was below, near and above nominal physiological temperature respectively.Highlights► A pH dependent thermo-sensitive copolymer with narrow window of LCST was synthesized. ► The CMC of micelles was corresponded to 4.0523 mg/L. ► The situation of TEMPO carrying micelles can be detected by ESR. ► The micelles showed non-toxicity towards cells, pointed to their biocompatibility.
Co-reporter:Xiangheng Niu, Yili Ding, Chen Chen, Hongli Zhao, Minbo Lan
Sensors and Actuators B: Chemical 2011 Volume 158(Issue 1) pp:383-387
Publication Date(Web):15 November 2011
DOI:10.1016/j.snb.2011.06.040
In this paper, a novel electrochemical biosensor for Hg2+ determination based on Hg2+-induced DNA hybridization is reported. A pair of oligonucleotides with seven strategically placed thymine–thymine (T–T) mismatched bases was introduced. Firstly, one oligonucleotide (P1) modified with hexanthiol at 5-terminal was immobilized on a screen-printed gold electrode (SPGE) via self-assembly. Then the other oligonucleotide (P2) tagged with a ferrocene derivative as electroactive indicator was able to hybridize with P1 by forming thymine–Hg2+–thymine (T–Hg2+–T) complexes in the presence of Hg2+, providing a detectable electrochemical signal of the ferrocene derivative. However, when Hg2+ was absent, the two oligonucleotides could not hybridize due to the T–T mismatched bases, and P2 could not be fixed on the electrode surface, with the indicator signal disappearing. Experimental results indicate that the proposed biosensor offers linear responses on Hg2+ concentration in the range of 10–0.001 μM, with a detection limit of 0.6 nM (S/N = 3). This new Hg2+-induced DNA hybridization strategy is demonstrated valid and efficient to detect trace Hg2+ with high sensitivity and good selectivity.
Co-reporter:MinBo Lan;Qin Zhou;YanHui Zhao;YuanJie Teng;Chen Chen
Science China Chemistry 2010 Volume 53( Issue 6) pp:1366-1370
Publication Date(Web):2010 June
DOI:10.1007/s11426-010-3091-3
An electrochemical DNA biosensor for specific-sequences detection of Vibrio parahaemolyticus (VP) was fabricated. A single-stranded 20-mer oligonucleotide (ssDNA) and 6-mercapto-1-hexanol (MCH) were immobilized via a thiol linker on gold disk electrodes by self-assembling. The ssDNA underwent hybridization in a hybridization solution containing complementary or non-complementary or single base pair mismatched DNA sequences of VP. Examination of changes in response to these three target DNAs showed that the developed biosensor had a high selectivity and sensitivity.
Co-reporter:YuanJie Teng;Chen Chen;ChangXiang Zhou;HongLi Zhao;MinBo Lan
Science China Chemistry 2010 Volume 53( Issue 12) pp:2581-2586
Publication Date(Web):2010 December
DOI:10.1007/s11426-010-4038-4
The screen-printed three-electrode system was applied to fabricate a new type of disposable amperometric xanthine oxidase biosensor. Carbon-working, carbon-counter and Ag/AgCl reference electrodes were all manually printed on the polyethylene terephthalate substrate forming the screen-printed three-electrode system by the conventional screen-printing process. As a mediator, Prussian blue could not only catalyze the electrochemical reduction of hydrogen peroxide produced from the enzyme reaction, but also keep the favorable potential around 0 V. The optimum operational conditions, including pH, potential and temperature, were investigated. The sensitivities of xanthine and hypoxanthine detections were 13.83 mA/M and 25.56 mA/M, respectively. A linear relationship was obtained in the concentration range between 0.10 μM and 4.98 μM for xanthine and between 0.50 μM and 3.98 μM for hypoxanthine. The small Michaelis-menten constant value of the xanthine oxidase biosensor was calculated to be 3.90 μM. The results indicate that the fabricated xanthine oxidase biosensor is effective and sensitive for the detection of xanthine and hypoxanthine.
Co-reporter:Shao-Hua Zuo, Ling-Fan Zhang, Hui-Hui Yuan, Min-Bo Lan, Geoffrey A. Lawrance, Gang Wei
Bioelectrochemistry 2009 Volume 74(Issue 2) pp:223-226
Publication Date(Web):February 2009
DOI:10.1016/j.bioelechem.2008.09.004
A simple, polishable and renewable DNA biosensor was fabricated based on a zirconia modified carbon paste electrode. Zirconia was mixed with graphite powder and paraffin wax to produce the paste for the electrode, and response-optimized at 56% graphite powder, 19% ZrO2 and 25% paraffin wax. An oligonucleotide probe with a terminal 5′-phosphate group was attached to the surface of the electrode via the strong affinity of zirconia for phosphate groups. DNA immobilization and hybridization were characterized by cyclic voltammetry and differential pulse voltammetry, using methylene blue as indicator. Examination of changes in response with complementary or non-complementary DNA sequences showed that the developed biosensor had a high selectivity and sensitivity towards hybridization detection (≤ 2 × 10− 10 M complementary DNA detectable). The surface of the biosensor can be renewed quickly and reproducibly (signal RSD ± 4.6% for five successive renewals) by a simple polishing step.
Co-reporter:Xiao Qiu, Hongli Zhao, Minbo Lan
Journal of Organometallic Chemistry 2009 694(24) pp: 3958-3964
Publication Date(Web):
DOI:10.1016/j.jorganchem.2009.08.012
Co-reporter:Y.J. Teng, S.H. Zuo, M.B. Lan
Biosensors and Bioelectronics 2009 Volume 24(Issue 5) pp:1353-1357
Publication Date(Web):1 January 2009
DOI:10.1016/j.bios.2008.07.062
Disposable hydrogen peroxide biosensor was developed based on the direct electron transfer of horseradish peroxidase (HRP) on porous screen-printed carbon electrodes. Conventional screen-printing process was manually performed to fabricate the planar carbon electrodes, which were endowed with porous surfaces especially after anodizing pretreatment. The cyclic voltammetry experiment indicated a pair of stable and well-defined redox peaks with a formal potential of −0.33 V. And the formal potential was pH-dependent, having a slope of −55.2 mV/pH which indicated one electron transfer. The heterogeneous electron transfer rate constant ks was estimated to be 13.28 ± 4.80 s−1. Additionally, the sensitivity was 143.3 mA M−1 cm−2 and the linear range was from 5.98 to 35.36 μM. In conclusion, the present work achieved the direct electron transfer of HRP on screen-printed electrodes without any promoters. The porous structure of screen-printed carbon electrodes facilitated the direct electron transfer between the active sites of HRP and the electrodes due to large amounts of conductive sites available on the surface for contacting with enzyme molecules. Moreover, the proposed biosensor could be mass-produced at low price, promising for commercial application.
Co-reporter:Yuanjie Teng, Xianbo Wu, Qin Zhou, Chen Chen, Hongli Zhao, Minbo Lan
Sensors and Actuators B: Chemical 2009 Volume 142(Issue 1) pp:267-272
Publication Date(Web):12 October 2009
DOI:10.1016/j.snb.2009.08.013
A disposable hydrogen peroxide biosensor was developed based on the direct electron transfer of myoglobin (Mb) on mesopores KIT-6 modified screen-printed electrode (SPE) which was manually performed to fabricate the planar carbon electrodes. KIT-6 is a new material which can absorb abundant of Mb molecules. A mixture of Mb and KIT-6 was immobilized with nafion on electrode. The cyclic voltammetry experiment indicated that a pair of stable and well-defined reduction peaks with a formal potentials of −0.35, and −0.28 V versus saturated calomel electrode (SCE) was obtained, using the present modified electrode in phosphate buffer saline (0.05 M, pH 7.0) at scan rate of 100 mV s−1, characteristic of Mb heme Fe(III)/Fe(II) redox couple. The heterogeneous electron transfer rate constant ks was estimated to be 16.93 s−1. And the formal potential was pH-dependent, having two slopes of −54.7 and −49.3 mV/pH which illustrated one electron transfer. This modified electrode was applied to detect H2O2 with sensitivity of 55.68 mA M−1 cm−2. Infrared spectrum and UV–vis absorption spectra of immobilized Mb film were recorded. In conclusion, KIT-6 increases the electron transfer activity of Mb and this kind of H2O2 biosensor is low cost for using disposable.
Co-reporter:Shaohua Zuo, Yuanjie Teng, Huihui Yuan, Minbo Lan
Sensors and Actuators B: Chemical 2008 Volume 133(Issue 2) pp:555-560
Publication Date(Web):12 August 2008
DOI:10.1016/j.snb.2008.03.024
A one-step enzyme immobilization process with silica sol–gel/polyvinyl alcohol was described to achieve direct electrochemistry of glucose oxidase on screen-printed electrodes. The immobilized glucose oxidase displays a couple of stable and well-defined redox peaks with an electron transfer rate constant of 8.38 s−1 and a formal potential of −460 mV (versus SCE) in phosphate buffer (0.05 M, pH 7.0) at a scan rate of 300 mV s−1. The results suggested that conformation and bioactivity of glucose oxidase could be retained efficiently using the proposed immobilization method and the porous structure of screen-printed electrode surface was helpful for electron communication of glucose oxidase and the electrode. Furthermore, the modified electrode was used as a glucose biosensor, exhibiting a linear response to glucose concentration ranging from 0 to 4.13 mM and a sensitivity of 3.47 μA mM−1 cm−2 at an applied potential of −0.5 V. The detection limit of the biosensor is 9.8 μM, based on a signal-to-noise ratio of 3. The present work provided a promising strategy for fabricating a novel and disposable mediatorless glucose biosensor, which could be mass-produced through further development.
Co-reporter:Weisheng Wang, Ye Wang, Liangju Yang, Baizhan Liu, Minbo Lan, Wenliang Sun
Thermochimica Acta 2005 Volume 437(1–2) pp:7-11
Publication Date(Web):15 October 2005
DOI:10.1016/j.tca.2005.06.002
Four kinds of reconstituted tobacco sheets were heated in a thermogravimetric analyzer in different atmospheres at the heating rate of 5 °C/min. The curves of thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA) of the reconstituted tobacco sheets were measured and compared. The profiles of the evolving product CO2 were also recorded by the thermogravimetric analyzer coupled to a Fourier transform infrared (TG-FTIR) spectrometer. The results of thermal analysis and the profiles of CO2 showed that the existence of O2 could strongly affect the thermal decomposition of the reconstituted tobacco sheets.
Co-reporter:Minbo Lan, Keiichi Ikegami
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2005 Volumes 257–258() pp:225-229
Publication Date(Web):5 May 2005
DOI:10.1016/j.colsurfa.2004.05.031
Langmuir–Blodgett (LB) films of mixtures of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), merocyanine dye (DO) and arachidic acid (C20) with different molecular ratios, were prepared on Cd2+-containing and pure-water subphases. The characterization of mixed Langmuir and LB films were performed by using, respectively, surface pressure–molecular area isothermetry and UV–Vis–IR absorption spectroscopy. The analysis indicates that interaction between the two dyes modifies their arrangements and electronic states in their mixed Langmuir films spread upon the Cd2+-containing subphase. However, the mixed LB films with the pure-water subphase are showed to be simple physical mixtures. The difference in the mixing effect observed for the Langmuir films upon the Cd-containing and pure-water subphases may be caused by the formation of metal chelation with the former subphase.
![5,7-dihydroxy-2-(4-hydroxyphenyl)-3-[(2s,3r,4s,5s,6r)-3,4,5-trihydroxy-6-[[(2r,3r,4r,5r,6s)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4-one](http://img.cochemist.com/ccimg/17700/17650-84-9.png)
![5,7-dihydroxy-2-(4-hydroxyphenyl)-3-[(2s,3r,4s,5s,6r)-3,4,5-trihydroxy-6-[[(2r,3r,4r,5r,6s)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4-one](http://img.cochemist.com/ccimg/17700/17650-84-9_b.png)
![Methanone,[(1R,5S,8R)-8-hydroxy-4,4,8-trimethyl-3-azabicyclo[3.3.1]non-2-en-2-yl]-1H-indol-3-yl-](http://img.cochemist.com/ccimg/160600/160568-09-2.png)
![Methanone,[(1R,5S,8R)-8-hydroxy-4,4,8-trimethyl-3-azabicyclo[3.3.1]non-2-en-2-yl]-1H-indol-3-yl-](http://img.cochemist.com/ccimg/160600/160568-09-2_b.png)
![1H-Cycloprop[e]azulene,decahydro-1,1,4-trimethyl-7-methylene-, (1aR,4R,4aR,7aR,7bR)-](http://img.cochemist.com/ccimg/73500/73464-47-8.png)
![1H-Cycloprop[e]azulene,decahydro-1,1,4-trimethyl-7-methylene-, (1aR,4R,4aR,7aR,7bR)-](http://img.cochemist.com/ccimg/73500/73464-47-8_b.png)
![Cyclobut[c]indene, 1,2,2a,3,4,4a,5,6-octahydro-2,2,4a,8-tetramethyl-, (2aR,4aS,8aR)-rel-(-)-](/data/chemimg/1851200/56633-28-4.png)
![Cyclobut[c]indene, 1,2,2a,3,4,4a,5,6-octahydro-2,2,4a,8-tetramethyl-, (2aR,4aS,8aR)-rel-(-)-](/data/chemimg/1851200/56633-28-4_b.png)
![1H-Cycloprop[e]azulene,decahydro-1,1,7-trimethyl-4-methylene-, (1aR,4aS,7R,7aR,7bS)-](http://img.cochemist.com/ccimg/25300/25246-27-9.png)
![1H-Cycloprop[e]azulene,decahydro-1,1,7-trimethyl-4-methylene-, (1aR,4aS,7R,7aR,7bS)-](http://img.cochemist.com/ccimg/25300/25246-27-9_b.png)
![Bicyclo[3.1.1]heptan-2-one, 6,6-dimethyl-](http://img.cochemist.com/ccimg/25000/24903-95-5.png)
![Bicyclo[3.1.1]heptan-2-one, 6,6-dimethyl-](http://img.cochemist.com/ccimg/25000/24903-95-5_b.png)
![Bicyclo[8.1.0]undeca-2,6-diene,3,7,11,11-tetramethyl-, (1S,2E,6E,10R)-](http://img.cochemist.com/ccimg/24800/24703-35-3.png)
![Bicyclo[8.1.0]undeca-2,6-diene,3,7,11,11-tetramethyl-, (1S,2E,6E,10R)-](http://img.cochemist.com/ccimg/24800/24703-35-3_b.png)
![Azulene, 1,2,3,3a,4,5,6,7-octahydro-1,4-dimethyl-7-(1-methylethenyl)-, [1R-(1α,3aβ,4α,7β)]-](http://img.cochemist.com/ccimg/22600/22567-17-5.png)
![Azulene, 1,2,3,3a,4,5,6,7-octahydro-1,4-dimethyl-7-(1-methylethenyl)-, [1R-(1α,3aβ,4α,7β)]-](http://img.cochemist.com/ccimg/22600/22567-17-5_b.png)
![Cyclohexene, 3-(1,5-dimethyl-4-hexenyl)-6-methylene-, [S-(R*,S*)]-](http://img.cochemist.com/ccimg/20400/20307-83-9.png)
![Cyclohexene, 3-(1,5-dimethyl-4-hexenyl)-6-methylene-, [S-(R*,S*)]-](http://img.cochemist.com/ccimg/20400/20307-83-9_b.png)
![12-Oxabicyclo[9.1.0]dodeca-3,7-diene, 1,5,5,8-tetramethyl-, (1R,3E,7E,11R)-](/data/chemimg/2249900/19888-34-7.png)
![12-Oxabicyclo[9.1.0]dodeca-3,7-diene, 1,5,5,8-tetramethyl-, (1R,3E,7E,11R)-](/data/chemimg/2249900/19888-34-7_b.png)
![Cyclobuta[1,2:3,4]dicyclopentene,decahydro-3a-methyl-6-methylene-1-(1-methylethyl)-, (1S,3aS,3bR,6aS,6bR)-](http://img.cochemist.com/ccimg/5300/5208-59-3.png)
![Cyclobuta[1,2:3,4]dicyclopentene,decahydro-3a-methyl-6-methylene-1-(1-methylethyl)-, (1S,3aS,3bR,6aS,6bR)-](http://img.cochemist.com/ccimg/5300/5208-59-3_b.png)
![Bicyclo[3.1.0]hex-2-ene, 2-methyl-5-(1-methylethyl)-](http://img.cochemist.com/ccimg/2900/2867-05-2.png)
![Bicyclo[3.1.0]hex-2-ene, 2-methyl-5-(1-methylethyl)-](http://img.cochemist.com/ccimg/2900/2867-05-2_b.png)
![3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzo[7]annulene](http://img.cochemist.com/ccimg/1500/1461-03-6.png)
![3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzo[7]annulene](http://img.cochemist.com/ccimg/1500/1461-03-6_b.png)
![1-[(4-METHOXYPHENYL)METHYL]-5-PYRIDIN-3-YLPYRROLIDIN-2-ONE](http://img.cochemist.com/ccimg/600/552-02-3.png)
![1-[(4-METHOXYPHENYL)METHYL]-5-PYRIDIN-3-YLPYRROLIDIN-2-ONE](http://img.cochemist.com/ccimg/600/552-02-3_b.png)
![6-METHYL-4-NITRO-1-(PHENYLSULFONYL)-1H-PYRROLO[2,3-B]PYRIDINE](http://img.cochemist.com/ccimg/500/495-60-3.png)
![6-METHYL-4-NITRO-1-(PHENYLSULFONYL)-1H-PYRROLO[2,3-B]PYRIDINE](http://img.cochemist.com/ccimg/500/495-60-3_b.png)
![1H-Cycloprop[e]azulen-4-ol,decahydro-1,1,4,7-tetramethyl-, (1aR,4R,4aR,7R,7aS,7bS)-](http://img.cochemist.com/ccimg/500/489-41-8.png)
![1H-Cycloprop[e]azulen-4-ol,decahydro-1,1,4,7-tetramethyl-, (1aR,4R,4aR,7R,7aS,7bS)-](http://img.cochemist.com/ccimg/500/489-41-8_b.png)
![1H-Cycloprop[e]azulene,1a,2,3,4,4a,5,6,7b-octahydro-1,1,4,7-tetramethyl-, (1aR,4R,4aR,7bS)-](http://img.cochemist.com/ccimg/500/489-40-7.png)
![1H-Cycloprop[e]azulene,1a,2,3,4,4a,5,6,7b-octahydro-1,1,4,7-tetramethyl-, (1aR,4R,4aR,7bS)-](http://img.cochemist.com/ccimg/500/489-40-7_b.png)
![2-Naphthalenemethanol, decahydro-α,α,4a-trimethyl-8-methylene-, [2R-(2α,4aα,8aβ)]-](http://img.cochemist.com/ccimg/500/473-15-4.png)
![2-Naphthalenemethanol, decahydro-α,α,4a-trimethyl-8-methylene-, [2R-(2α,4aα,8aβ)]-](http://img.cochemist.com/ccimg/500/473-15-4_b.png)
