Yi Liu

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Name: 刘义; Liu, Yi

Organization: Wuhan University , China

Department: College of Chemistry and Molecular Sciences

Title: Professor(PhD)

TOPICS

Material Chemistry

Fullerene

Chemicals
References

Red, Yellow, and Blue Luminescence by Graphene Quantum Dots: Syntheses, Mechanism, and Cellular Imaging

Co-reporter:Tian Gao, Xi Wang, Li-Yun Yang, Huan He, Xiao-Xu Ba, Jie Zhao, Feng-Lei Jiang, and Yi Liu

ACS Applied Materials & Interfaces July 26, 2017 Volume 9(Issue 29) pp:24846-24846

Publication Date(Web):July 5, 2017

DOI:10.1021/acsami.7b05569

Owing to their excellent photoluminescence (PL) properties, good biocompatibility, and low toxicity, graphene quantum dots (GQDs) are widely applied in bioimaging, biosensing, and so forth. However, further development of GQDs is limited by their synthetic methodology and unclear PL mechanism. Therefore, it is urgent to find efficient and universal methods for the synthesis of GQDs with high stability, controllable surface properties, and tunable PL emission wavelength. By coating with polyethyleneimine (PEI) of different molecular weights, blue-, yellow-, and red-emitting GQDs were successfully prepared. By transmission electron microscopy, atomic force microscopy, and dynamic light scattering, the characterization of size and morphology revealed that blue-emitting PEI1800 GQDs were monocoated, like jelly beans, and red-emitting PEI600 GQDs were multicoated, like capsules. The amidation reaction between carboxyl and amide functional groups played an important role in the coating process, as evidenced by IR spectroscopy and theoretical calculation with density functional theory B3LYP/6-31G*. The PL-tunable GQDs exhibited an excellent chemical stability and extremely low cytotoxicity, and they had been shown to be feasible for bioimaging, making these GQDs highly attractive for a wide variety of applications, including multicolor imaging and bioanalysis.Keywords: cellular imaging; coating nanomaterials; Graphene quantum dots; photoluminescence mechanism; photoluminescence tunable; polyethyleneimine;

Spectroscopic, Polarographic, and Microcalorimetric Studies on Mitochondrial Dysfunction Induced by Ethanol

Co-reporter:Long Ma;Jia-Xin Dong;Can Wu;Xue-Yi Li;Jing Chen

The Journal of Membrane Biology 2017 Volume 250( Issue 2) pp:195-204

Publication Date(Web):2017 April

DOI:10.1007/s00232-017-9947-0

Liver mitochondria are involved in several important life processes; mitochondrial dysfunction and disorders are implicated in several human diseases. Alcohol permeates all tissues of the body and exerts some intrinsic hepatotoxicity. In this work, our results demonstrated that ethanol caused a series of mitochondria permeability transition pore (MPTP) opening factors such as mitochondrial swelling, increased permeability of H+ and K+, collapsed membrane potential, and increased membrane fluidity. Furthermore, mitochondrial ultrastructure alternation observed clearly by transmission electron microscopy and the release of Cytochrome c could explain the MPTP opening from another aspect. Moreover, ethanol damaged the mitochondrial respiration system and induced disturbance of mitochondrial energy metabolism which was monitored by polarographic and microcalorimetric methods, respectively. Considered together, these damages may promote both apoptotic and necrotic cell death and contribute to the onset or progression alcohol-induced liver diseases.

Identification of Binding Modes for Amino Naphthalene 2-Cyanoacrylate (ANCA) Probes to Amyloid Fibrils from Molecular Dynamics Simulations

Co-reporter:Huan He, Juan Xu, Dan-Yang Cheng, Li Fu, Yu-Shu Ge, Feng-Lei Jiang, and Yi Liu

The Journal of Physical Chemistry B 2017 Volume 121(Issue 6) pp:

Publication Date(Web):January 12, 2017

DOI:10.1021/acs.jpcb.6b10460

The amino naphthalene 2-cyanoacrylate (ANCA) probe is a kind of fluorescent amyloid binding probe that can report different fluorescence emissions when bound to various amyloid deposits in tissue, while their interactions with amyloid fibrils remain unclear due to the insoluble nature of amyloid fibrils. Here, all-atom molecular dynamics simulations were used to investigate the interaction between ANCA probes with three different amyloid fibrils. Two common binding modes of ANCA probes on Aβ40 amyloid fibrils were identified by cluster analysis of multiple simulations. The van der Waals and electrostatic interactions were found to be major driving forces for the binding. Atomic contacts analysis and binding free energy decomposition results suggested that the hydrophobic part of ANCA mainly interacts with aromatic side chains on the fibril surface and the hydrophilic part mainly interacts with positive charged residues in the β-sheet region. By comparing the binding modes with different fibrils, we can find that ANCA adopts different conformations while interacting with residues of different hydrophobicity, aromaticity, and electrochemical properties in the β-sheet region, which accounts for its selective mechanism toward different amyloid fibrils.

Mn-Doped ZnSe quantum dots initiated mild and rapid cation exchange for tailoring the composition and optical properties of colloid nanocrystals: novel template, new applications

Co-reporter:Zhi-Qiang Zhou;Li-Yun Yang;Ren Yan;Jie Zhao;Yu-Qi Liu;Lu Lai;Feng-Lei Jiang;Thomas Maskow

Nanoscale (2009-Present) 2017 vol. 9(Issue 8) pp:2824-2835

Publication Date(Web):2017/02/23

DOI:10.1039/C6NR09094J

Although cation exchange (CE) has been studied for many years and some mechanisms were proposed, there is still a knowledge gap in CE and problems such as the need for high temperature and it being time-consuming are still unaddressed. We developed a new mild strategy for CE by introducing a new ideal template and first applied this doping strategy to detect Cd2+ and Hg2+. This strategy adopted Mn-doped ZnSe quantum dots (QDs) as the template and the introduction occurs via a two-step CE reaction: first Zn2+ was partially substituted by X (X = Cd2+, Hg2+, Cu2+, Ag+ or Pb2+), later Mn2+ (in the deep structure of QDs) was substituted by X. Remarkably, Mn2+ in the lattice can be easily substituted by a dopant and its replacement by a dopant helps to bury the metal ions. The ultra-fast introduction of Cd2+ and Hg2+ (70 minutes for Cd2+ and 19 minutes for Hg2+) was realized at room temperature; other metal ions such as Ag+, Cu2+ and Pb2+ can be buried at 50 °C. This mild reaction temperature offers a solution for introducing impurities without sacrificing the interfacial structure of nanocrystals. HRTEM, XPS and ICP measurements were applied to analyze the introduction process. Furthermore, the spectroscopic method was employed to analyze the introduction, migration and distribution of metal ions. Then, we proposed a mechanism for the chemical conversion of nanocrystals by CE. Through this strategy, full-color light-emitting doped QDs were fabricated. Strikingly, a new turn-on probe for the detection of Cd2+ and Hg2+ with improved selectivity was developed by adopting this doping strategy. The detection limit is 36 nM for Cd2+ and 20 nM for Hg2+, which is competitive with the limit of detection reported by other groups using QDs as sensors.

Identification of the quinolinedione inhibitor binding site in Cdc25 phosphatase B through docking and molecular dynamics simulations

Co-reporter:Yushu Ge;Marc van der Kamp

Journal of Computer-Aided Molecular Design 2017 Volume 31( Issue 11) pp:995-1007

Publication Date(Web):09 October 2017

DOI:10.1007/s10822-017-0073-y

Cdc25 phosphatase B, a potential target for cancer therapy, is inhibited by a series of quinones. The binding site and mode of quinone inhibitors to Cdc25B remains unclear, whereas this information is important for structure-based drug design. We investigated the potential binding site of NSC663284 [DA3003-1 or 6-chloro-7-(2-morpholin-4-yl-ethylamino)-quinoline-5, 8-dione] through docking and molecular dynamics simulations. Of the two main binding sites suggested by docking, the molecular dynamics simulations only support one site for stable binding of the inhibitor. Binding sites in and near the Cdc25B catalytic site that have been suggested previously do not lead to stable binding in 50 ns molecular dynamics (MD) simulations. In contrast, a shallow pocket between the C-terminal helix and the catalytic site provides a favourable binding site that shows high stability. Two similar binding modes featuring protein-inhibitor interactions involving Tyr428, Arg482, Thr547 and Ser549 are identified by clustering analysis of all stable MD trajectories. The relatively flexible C-terminal region of Cdc25B contributes to inhibitor binding. The binding mode of NSC663284, identified through MD simulation, likely prevents the binding of protein substrates to Cdc25B. The present results provide useful information for the design of quinone inhibitors and their mechanism of inhibition.

The relationship between the length of surface ligand and effects of CdTe quantum dots on the physiological functions of isolated mitochondria

Co-reporter:Xun Xiang, Can Wu, Bo-Rui Zhang, Tao Gao, Jie Zhao, Long Ma, Feng-Lei Jiang, Yi Liu

Chemosphere 2017 Volume 184(Volume 184) pp:

Publication Date(Web):1 October 2017

DOI:10.1016/j.chemosphere.2017.06.091

•MPA-CdTe QDs had a stronger effect on MPT than TGA-CdTe QDs.•The weaker effect of TGA-CdTe QDs on MPT might be owing to their better stability and thus less amount of released Cd2+.•Surface ligands play an important role in the toxicity of CdTe quantum dots at the sub-cellular level.The potential toxicity of Quantum dots (QDs) should be assessed comprehensively for their fast spreading applications. Many studies have shown the toxicity of QDs is associated with their surface ligands. In this work, two analog ligands with one carbon difference, 2-mercaptoacetic acid (TGA) and 3-mercaptopropionic acid (MPA) were used as coating materials in the syntheses of two types of CdTe QDs with similar physicochemical properties. Then the biological effects of QDs on isolated mitochondria were studied. It was found that the two types of QDs could impair mitochondrial respiration and induce mitochondrial permeability transition (MPT). However, as compared with TGA-CdTe QDs, MPA-CdTe QDs had a stronger effect on MPT. The weaker effect of TGA-CdTe QDs on MPT might be owing to their better stability and thus less amount of released Cd2+, which could be further explained by the stronger affinity between the ligand (TGA) and the cadmium complexes in the crystal growth of QDs. These results highlighted the importance of ligands responsible for the toxicity of QDs at the sub-cellular level.Download high-res image (228KB)Download full-size image

Controlled preparation and highly photocatalytic activity of portable MCC-g-GMA@TiO2 photocatalyst by pre-radiation grafting-embedding method

Co-reporter:Yue-Sheng Li, Jiang-Tao Qin, Yan Han, Ji-Fu Du, Zhi-Bing Dong, Shao-Fa Sun, Yi Liu

Applied Catalysis B: Environmental 2017 Volume 218(Volume 218) pp:

Publication Date(Web):5 December 2017

DOI:10.1016/j.apcatb.2017.03.083

•MCC-g-GMA@TiO2 is prepared by pre-radiation grafting-embedding method.•TiO2 was successfully introduced into the surfaces of MCC resin.•Portable MGT have a higher photocatalytic performance than single component.•Synergistic effects of adsorption-enrichment and photocatalytic degradation were attributed to the excellent photocatalytic activity.•MGT photocatalyst contains the excellent properties of high photo-stability, more recycles and good separation-free.A portable and high efficient photocatalytic properties of MCC-g-GMA@TiO2 (MGT) photocatalyst based on micocrystaline cellulose (MCC) surfaces is prepared by pre-radiation grafting-embedding method. TiO2 nanoparticles were successfully introduced into the surfaces of novel MCC resin and manifested by FTIR, TG, XRD. Microstructure of MGT was characterized further by FESEM-EDS, FESEM-EDX mapping, HRTEM and BET. The highly photocatalytic activity of MGT was tested by the degradation of methyl blue dye (MB) in the aqueous medium under Xenon arc lamp. The results showed that the portable MGT resin complex system also had a highest photocatalytic performance at the appropriate content of TiO2 (4.22 wt%) and suitable radiation dose (60 kGy). Perhaps primary reasons were attributed to the synergistic effect of adsorption-enrichment and photocatalytic degradation. In addition, the high recycling ability of MGT complex confirms that photocatalyst is highly photostability and exhibited good separation-free. Overall, this portable MGT photocatalyst has good potential for application in the field of water pollution treatment.Download high-res image (214KB)Download full-size image

Indium (III) induces isolated mitochondrial permeability transition by inhibiting proton influx and triggering oxidative stress

Co-reporter:Lian Yuan, Jiaqi Zhang, Yujiao Liu, Jie Zhao, Fenglei Jiang, Yi Liu

Journal of Inorganic Biochemistry 2017 Volume 177(Volume 177) pp:

Publication Date(Web):1 December 2017

DOI:10.1016/j.jinorgbio.2017.08.012

•Multimode is first used to detect mitochondria properties.•The effects of indium on subcellular level are first proposed.•Flow cytometry and microcalorimetry are used to monitor mitochondria.While Indium's toxicity to organs is realized, its effects on mitochondria are still under investigation. Mitochondrial permeability transition (MPT) is widely accepted in mitochondrial dysfunction approaches and its importance in metal-induced mitochondrial degradation has been proposed. Since mitochondria are respiratory organelles, their interaction with free In3 + is analyzed to access structural and functional changes. Spectral methods and multimode plate reader was used to detect mitochondrial swelling, membrane potential, membrane fluidity, and inner membrane permeability. Flow cytometry was employed to detect mitochondrial reactive oxygen species (ROS) generation and transmission electron microscopy to image mitochondria. And oxygen electrode was used to measure respiratory rate, microcalorimetry to monitor long-term real-time mitochondrial metabolism. In3 + at a concentration up to 1 mM induces mitochondrial swelling, membrane depolarization and inhibits the protons transportation. In3 +-induced mitochondrial swelling and membrane depolarization is protected by MPT inhibitors and -SH protectors, but the influence on protons transportation is not protected. In addition, In3 + is able to accelerate the ROS production and inhibit the electron transition and respiratory chain while it stimulates long-term metabolism. Our findings show that In3 + induces MPT by inhibiting the proton channels located in the inner mitochondrial membrane and by stimulating mitochondrial oxidative stress.Download high-res image (241KB)Download full-size image

Impact of carbon quantum dots on dynamic properties of BSA and BSA/DPPC adsorption layers

Co-reporter:Lu Lai, Xiao-Qian Wei, Wei-Hua Huang, Ping Mei, Zhao-Hua Ren, Yi Liu

Journal of Colloid and Interface Science 2017 Volume 506(Volume 506) pp:

Publication Date(Web):15 November 2017

DOI:10.1016/j.jcis.2017.07.046

The effects of carbon quantum dots (CQDs) on the dynamic properties of bovine serum albumin (BSA) were investigated using pendant drop profile analysis method. Moreover, the effects of CQDs on the competitive adsorption of BSA and dipalmitoyl phosphatidylcholine (DPPC) were examined. CQDs reduce the fluorescence intensity of BSA and cause a red shift in fluorescence emission. The quenching constant at pH 4.3 is almost twice as large as that of the value obtained at pH 6.0. A small amount of CQDs does not influence the dynamic surface adsorption properties of BSA molecules. As the CQD concentration increases, a gradual increase in adsorption rate of BSA molecules is observed. Moreover, the addition of CQDs results in a significant transition of kinetic dependencies of surface elasticity of BSA solution when the CQD concentration exceeds a critical value. The appearance of the maximum surface elasticity value is probably attributed to the formation of tails and loops. When the dynamic surface properties are dominated by BSA molecules, the effects of CQDs on the surface properties of BSA/DPPC mixture are similar to those of BSA alone. However, when the surface film mainly consists of DPPC, CQDs can obviously change the interfacial properties of DPPC monolayer.Download high-res image (134KB)Download full-size image

Design, synthesis, cell imaging, kinetics and thermodynamics of reaction-based turn-on fluorescent probes for the detection of biothiols

Co-reporter:Fang-Fang Wang, Xiao-Yang Fan, Yu-Jiao Liu, Tao Gao, Rong Huang, Feng-Lei Jiang, Yi Liu

Dyes and Pigments 2017 Volume 145(Volume 145) pp:

Publication Date(Web):1 October 2017

DOI:10.1016/j.dyepig.2017.06.033

•Pentafluorophenyl substituent on the meso position of BODIPY leads to bright emission in the red region.•The fluorescent probes are sensitive enough to detect and image the endogenous thiols in living cells.•This is a rare example for the kinetics and thermodynamics of the reactions between the fluorescent probes and biothiols.Two highly selective red-emitting fluorescent “OFF-ON” probes (3a and 3b) with a BODIPY core were designed and synthesized, based on the recovery of fluorescence upon the cleavage of the fluorescence quenching unit of 2, 4-dinitrobenzenesulfonyl (DNBS) by biothiols. The probes showed 43-fold (3a, λem = 610 nm) and 33-fold (3b, λem = 582 nm) fluorescence enhancement respectively in the presence of biothiols. Compared with 3b, the introduction of five strong electron-withdrawing fluorine atoms in 3a, not only caused a red shift of the emission maximum for 28 nm, but also increased the fluorescence enhancement. Since they had stable fluorescence emission within physiological pH range, the two probes can be applied in imaging of living cells. In contrast, no such fluorescence response was observed in the cells pre-treated with N-ethylmaleimide (NEM), a well-known thiol scavenger. A non-linear curve-fitting of high quality was used to fit the spectroscopic data to determine the pseudo-first-order rate constants and the chemical equilibrium constants at different given temperatures (e.g. 310 K, 298 K and 288 K). Activation energy (Ea) and thermodynamic parameters, including Gibbs free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS), could be calculated. To the best of our knowledge, this was the first report for the chemical kinetics and thermodynamics of the reaction between the fluorescent probes and thiols. This work would greatly inspire the future design of even better fluorescent probes.The fluorescent probes are sensitive enough to detect and image the endogenous thiols in living cells. This is a rare example for the kinetics and thermodynamics of the reactions between the fluorescent probes and thiols.Download high-res image (243KB)Download full-size image

Characterization of fullerenol-protein interactions and an extended investigation on cytotoxicity

Co-reporter:Li-Yun Yang, Si-Yu Hua, Zhi-Qiang Zhou, Guan-Chao Wang, Feng-Lei Jiang, Yi Liu

Colloids and Surfaces B: Biointerfaces 2017 Volume 157(Volume 157) pp:

Publication Date(Web):1 September 2017

DOI:10.1016/j.colsurfb.2017.05.065

•Fullerenol interacts with BSA and γ-globulins in similar behaviors.•Proteins bind to fullerenol in a cooperative fashion.•Fullerenol has little influence on the conformation of proteins.•The presence of proteins mitigates the cytotoxicity of fullerenol.Fullerenols, known as polyhydroxylated derivatives of fullerene, have attracted great attention due to their distinctive material properties and potential applications in biology and medicine. As a step toward the elucidation of basic behavior in biological systems, a variety of spectroscopic measurements as well as isothermal titration calorimetry (ITC) were applied to study the interaction between fullerenol (C60(OH)44) and serum proteins (bovine serum albumin (BSA) and γ-globulins). The results of fluorescence spectra indicated that the intrinsic fluorescence of proteins could be effectively quenched by the dynamic mechanism. The affinity values of both proteins bound to fullerenol were of the same order of magnitude. Meanwhile, ITC results showed that the interaction between fullerenol and BSA was enthalpy favorable, while the interaction with γ-globulins was enthalpy unfavorable. Furthermore, fullerenol had little influence on the secondary structure of both proteins. Additional cytotoxicity tests showed that the presence of proteins attenuated the toxic effect of fullerenol on human normal gastric epithelial cell line (GES-1). Thus, the interaction between fullerenol and proteins is indispensable to evaluate the biosafety of fullerenol, which may in turn promotes the development of its biological applications.The adsorption of proteins reduced fullerenol-induced cytotoxicity in human normal gastric epithelial cells.Download high-res image (126KB)Download full-size image

Silver ion-induced mitochondrial dysfunction via a nonspecific pathway

Co-reporter:L. Yuan;T. Gao;H. He;F. L. Jiang;Y. Liu

Toxicology Research (2012-Present) 2017 vol. 6(Issue 5) pp:621-630

Publication Date(Web):2017/08/29

DOI:10.1039/C7TX00079K

Silver, once regarded as a safe noble metal for humans, has been widely used in industrial and commercial products, especially in nanometer biomaterials. It is now well known that Ag+ is biologically active and is able to interact with the cell membrane, proteins and DNA. However, very little is understood about the potential impacts of Ag+ at the sub-cellular level. Our work investigated the potential toxicity of Ag+ on mitochondria isolated from rat livers by examining the mitochondrial morphology, respiration, swelling, membrane fluidity and reactive oxygen species (ROS) generation. We observed that Ag+ significantly affects the mitochondrial structure and function, including mitochondrial swelling, collapse of the transmembrane potential, change of permeability and fluidity, decline of the respiratory rate, and acceleration of ROS, indicating that Ag+ should be seriously regarded as a potentially hazardous substance. Moreover, we conclude that Ag+ injures the mitochondrial structure and function by a nonspecific approach, in which the interaction is unregulated by inherent parts such as the mitochondria permeability transition pore (MPTP). These results help us learn more about the toxicity of Ag+ at the subcellular (mitochondrial) level and influence future biological and medical applications of Ag-based materials.

Active site-targeted carbon dots for the inhibition of human insulin fibrillation

Co-reporter:Q. Q. Yang;J. C. Jin;Z. Q. Xu;J. Q. Zhang;B. B. Wang;F. L. Jiang;Y. Liu

Journal of Materials Chemistry B 2017 vol. 5(Issue 10) pp:2010-2018

Publication Date(Web):2017/03/08

DOI:10.1039/C6TB02823C

Carbon nano-dots (C-Dots) possess great benign properties, making them ideal for use in biomedical fields, especially due to their high aqueous solubility, outstanding photoluminescence (PL), favorable biocompatibility, low toxicity, chemical inertness, and easy functionalization properties. Herein, the C-Dots with sizes of about 2.4 ± 0.9 nm and containing the groups –OH, CC and CO, were shown to prolong the lag phase of human insulin (HI) fibrillation following a dose-dependent manner in an in vitro study. The spontaneous growth of fibrils after a lag phase was accompanied by exothermic heat, determined by isothermal titration calorimetry (ITC), demonstrating the inhibitory effect of C-Dots. Moreover, as the dose of C-Dots was increased to 4 mg mL−1, the fibrillation process could be totally deterred for more than half a month. However, the deterrent effect of the C-Dots on HI fibrillation disappeared when just a few fibril seeds were added. This is because the association constant of HI monomers interacting with fibril seeds (K2: 1.56 × 105 M−1) is much larger than that with C-Dots (K2: 8.28 × 103 M−1), as determined by analyzing the ITC results. An ‘‘active-site targeted’’ inhibitory mechanism has also been proposed. The “active site” is mainly on the B-chain of HI, and the ITC results show that the binding between the C-Dots and HI monomers is mainly driven by the electrostatic force. This is the first time that the anti-fibrillation mechanism in the presence of C-Dots has been analyzed by ITC. These results indicate that ITC is a promising approach for comprehensively clarifying the mechanisms of protein fibrillation inhibition.

Ultrasmall silver nanoclusters: Highly efficient antibacterial activity and their mechanisms

Co-reporter:Jian-Cheng Jin;Xiao-Juan Wu;Juan Xu;Bei-Bei Wang;Feng-Lei Jiang

Biomaterials Science (2013-Present) 2017 vol. 5(Issue 2) pp:247-257

Publication Date(Web):2017/01/31

DOI:10.1039/C6BM00717A

Silver materials have been widely used as antimicrobial agents. Notably, silver nanoparticles have emerged as a new generation of nanoproducts for biomedical and environmental applications in recent years. However, ultrasmall silver nanoclusters (NCs) (∼2 nm) have rarely been used to kill bacteria and their antibacterial mechanisms have not yet been fully elucidated. Herein, we studied the antibacterial activities of bifunctional fluorescent DHLA-AgNCs against three types of bacteria. The results showed that DHLA-AgNCs exhibited excellent antibacterial activities against Gram-negative E. coli, which could efficiently inhibit the growth of E. coli DH 5α and E. coli DSM 4230 cells at a concentration of 15 and 10 μg mL−1, respectively. Meanwhile AgNCs demonstrated no apparent antibacterial activity against Gram-positive S. aureus. Then, the antibacterial mechanisms of AgNCs were systematically investigated. We found that AgNCs affected the growth of different E. coli strains in different ways. AgNCs inhibited the growth of E. coli DH 5α mainly through damaging the outer cellular membrane and permeating into the cells, followed by the antibacterial effect of the internalized AgNCs and released silver ions. AgNCs, however, inhibited the growth of E. coli DSM 4230 cells mainly through diffusing into E. coli DSM 4230 cells and damaging their respiratory chain. These results clearly indicated that different bacterial strains (e.g. different E. coli strains) should be taken into consideration in future studies. Our work facilitates further investigation of the design of new antibacterial silver nanomaterials with different sizes.

Photosensitive antibacterial and cytotoxicity performances of a TiO2/carboxymethyl chitosan/poly(vinyl alcohol) nanocomposite hydrogel by in situ radiation construction

Co-reporter:Yue-Sheng Li;Yan Han;Jiang-Tao Qin;Zhi-Yong Song;Hua-Hua Cai;Ji-Fu Du;Shao-Fa Sun

Journal of Applied Polymer Science 2016 Volume 133( Issue 44) pp:

Publication Date(Web):

DOI:10.1002/app.44150

ABSTRACT

Nano-TiO₂/carboxymethyl chitosan (CMCS)/poly(vinyl alcohol) (PVA) ternary nanocomposite hydrogels were prepared by freezing–thawing cycles and electron-beam radiation with PVA, CMCS, and nano-TiO₂ as raw materials. The presence of nano-TiO₂ nanoparticles in the composite hydrogels was confirmed by thermogravimetry, Fourier transform infrared spectroscopy, and X-ray powder diffraction. Field emission scanning electron microscopy images also illustrated that the TiO₂/CMCS/PVA hydrogel exhibited a porous and relatively regular three-dimensional network structure; at the same time, there was the presence of embedded nano-TiO₂ throughout the hydrogel matrix. In addition, the nano-TiO₂/CMCS/PVA composite hydrogels displayed significant antibacterial activity with Escherichia coli and Staphylococcus aureus as bacterial models. The antibacterial activity was demonstrated by the antibacterial circle method, plate count method, and cell density method. Also, with the Alamar Blue assay, the cytotoxicity of the composite hydrogel materials to L929 cells was studied. The results suggest that these materials had no obvious cytotoxicity. Thus, we may have developed a novel, good biocompatibility hydrogel with inherent photosensitive antibacterial activity with great potential for applications in the fields of cosmetics, medical dressings, and environmental protection. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44150.

Size Effects on the Interaction of QDs with the Mitochondrial Membrane In Vitro

Co-reporter:Lu Lai;Ya-Ping Li;Ping Mei;Wu Chen;Feng-Lei Jiang

The Journal of Membrane Biology 2016 Volume 249( Issue 6) pp:757-767

Publication Date(Web):2016 December

DOI:10.1007/s00232-016-9920-3

The mitochondrial toxicity induced by GSH-CdTe Quantum dots (QDs) of different sizes was investigated. The decreases in absorbance and transmission electron microscopy images show that QDs induce the swelling of mitochondria. Results of flow cytometry indicate that QDs cause a reduction of mitochondrial membrane potential (MMP). A remarkable increase in fluidity of protein regions of mitochondrial membrane is observed, whereas the lipid regions are not obviously affected. Cyclosporin A (CsA) effectively prevents the QD-induced mitochondrial swelling. On the basis of these results, it is proposed that QDs induce mitochondrial permeability transition (MPT). Moreover, with increasing QDs size, a pronounced MPT is observed. The difference between the membrane fluidity induced by QDs and Cadmium ion and the ineffective protective effects of EDTA suggests that the mitochondrial toxicity of QDs cannot be only attributed to the release of metal ion. The protective effects of HSA indicate that the interaction of QDs with pore-forming protein gives rise to the increase in membrane fluidity. This hypothesis is demonstrated by the interaction of QDs with model membranes and proteins using differential scanning calorimetry and isothermal titration microcalorimetry. In conclusion, as the size of QDs increases, the binding affinity of QDs with membrane protein increases, and therefore causes a pronounced mitochondrial damage.

Highly Photoluminescent Nitrogen-Doped Carbon Nanodots and Their Protective Effects against Oxidative Stress on Cells

Co-reporter:Zi-Qiang Xu, Jia-Yi Lan, Jian-Cheng Jin, Ping Dong, Feng-Lei Jiang, and Yi Liu

ACS Applied Materials & Interfaces 2015 Volume 7(Issue 51) pp:28346

Publication Date(Web):December 7, 2015

DOI:10.1021/acsami.5b08945

Highly photoluminescent (PL) (quantum yield = 54%) nitrogen doped carbon nanodots (C-dots) have been prepared through one-step carbonizing citric acid and tris(hydroxymethyl)aminomethane and using oleic acid as solvent. The synthesized C-dots are monodisperse with narrow size distribution (average 1.7 nm). The PL properties of C-dots are pH dependent, and hence, using C-dots as sophisticated pH sensor to detect pH values between 7 and 9 can be expected. In addition, the PL intensity of C-dots remains stable under high ionic strength. The C-dots can protect cells from oxidative stress, which shows potential to expand the biological application of C-dots, especially in medical treatment. The protective mechanism is associated with intracellular reactive oxygen species elimination and the intracellular superoxide dismutase production.Keywords: carbon nanodots; highly photoluminescent; nitrogen doped; oxidative stress; protective effects

One-step synthesis of silver nanoparticles using carbon dots as reducing and stabilizing agents and their antibacterial mechanisms

Co-reporter:Jian-Cheng Jin, Zi-Qiang Xu, Ping Dong, Lu Lai, Jia-Yi Lan, Feng-Lei Jiang, Yi Liu

Carbon 2015 Volume 94() pp:129-141

Publication Date(Web):November 2015

DOI:10.1016/j.carbon.2015.05.084

Silver nanoparticles (AgNPs) are potent and broad-spectrum antimicrobial agents. Herein, a novel one-step method has been used to synthesize AgNPs, in which fluorescent carbon dots (CDs) were used as reducing and stabilizing agents. To the best of our knowledge, the use of CDs as reducing and stabilizing agents has rarely been reported in conjunction with their use in the fabrication of AgNPs. Subsequently, their antibacterial activities were investigated. The results demonstrated that the surface property of AgNPs could influence the stability of AgNPs leading to different bactericidal effects. The size of the synthesized AgNPs was smaller when CDs were doped with sulfur. These small AgNPs exhibit better stability in culture medium contributing to excellent bactericidal activity, which can completely inhibit the growth of Escherichia coli (E. coli) at a concentration of 150 μM of silver atom. Finally, the possible antibacterial mechanisms of AgNPs were proposed as follows: first, AgNPs can be absorbed easily onto the surface of E. coli and affect the permeability and fluidity of the outer membrane; second, AgNPs with smaller size (7.3 ± 1.0 and 6.1 ± 0.8 nm) can permeate the membrane of E. coli to interact with DNA and the respiratory chain; and third, the release of Ag+ can cause E. coli death.

Resonance energy transfer, pH-induced folded states and the molecular interaction of human serum albumin and icariin

Co-reporter:Xiao-Xia Cheng;Xiao-Yang Fan;Feng-Lei Jiang;Yi. Liu;Ke-Lin Lei

Luminescence 2015 Volume 30( Issue 7) pp:1026-1033

Publication Date(Web):

DOI:10.1002/bio.2854

Abstract

Icariin is a flavonol glycoside with a wide range of pharmacological and biological activities. The pharmacological and biological functions of flavonoid compounds mainly originate from their binding to proteins. The mode of interaction of icariin with human serum albumin (HSA) has been characterized by fluorescence spectroscopy and far- and near-UV circular dichroism (CD) spectroscopy under different pH conditions. Fluorescence quenching studies showed that the binding affinity of icariin with HSA in the buffer solution at different pH values is: K_a (pH 4.5) > K_a (pH 3.5) > K_a (pH 9.0) > K_a (pH 7.0). Red-edge excitation shift (REES) studies revealed that pH had an obvious effect on the mobility of the tryptophan microenvironment and the addition of icariin made the REES effect more distinct. The static quenching mechanism and number of binding sites (n ≈ 1) were obtained from fluorescence data at three temperatures (298, 304 and 310 K). Both ∆H⁰ < 0 and ∆Ѕ⁰ < 0 suggested that hydrogen bonding and van der Waal's interaction were major driving forces in the binding mechanism, and this was also confirmed by the molecular simulation results. The distance r between the donor (HSA) and the acceptor (icariin) was calculated based on Förster non-radiation energy transfer theory. We found that pH had little impact on the energy transfer between HSA and icariin. Far- and near-UV CD spectroscopy studies further indicated the influence of pH on the complexation process and the alteration in the protein conformation upon binding. Copyright © 2015 John Wiley & Sons, Ltd.

Comparison of interactions between human serum albumin and silver nanoparticles of different sizes using spectroscopic methods

Co-reporter:Wanju Zhang;Qingbo Zhang;Fang Wang;Lian Yuan;Ziqiang Xu;Fenglei Jiang

Luminescence 2015 Volume 30( Issue 4) pp:397-404

Publication Date(Web):

DOI:10.1002/bio.2748

Abstract

Three different sizes (15.9 ± 2.1 nm, 26.4 ± 3.2 nm and 39.8 ± 4.0 nm, respectively) of citrate-coated silver nanoparticles (SNPs) have been synthesized and characterized. The interactions of the synthesized SNPs with human serum albumin (HSA) at physiological pH have been systematically studied by UV-vis absorption spectroscopy, fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy and circular dichroism (CD) spectroscopy. The results indicate that the SNPs can bind to HSA with high affinity and quench the intrinsic fluorescence of HSA. The binding constants and quenching rate constants were calculated. The apparent association constants (K_app) values are 2.14 × 10⁴ M^–1 for 15.9 nm SNP, 1.65 × 10⁴ M^–1 for 26.4 nm SNP and 1.37 × 10⁴ M^–1 for 39.8 nm SNP, respectively. The values of binding constant obtained from the fluorescence quenching data match well with that determined from the absorption spectral changes. These results suggest that the smaller SNPs have stronger interactions to HSA than the larger ones at the same concentrations. Synchronous fluorescence, three-dimensional fluorescence and CD spectroscopy studies show that the synthesized SNPs can induce slight conformational changes in HSA. Copyright © 2014 John Wiley & Sons, Ltd.

Thermodynamic Properties of the Site-selective Binding of a Bromo-hydrazone and Its Unsubstituted Analogue to Human Serum Albumin

Co-reporter:Jin-Qiang Tong;Fang-Fang Tian;Feng-Lei Jiang

Journal of Solution Chemistry 2015 Volume 44( Issue 2) pp:193-205

Publication Date(Web):2015 February

DOI:10.1007/s10953-015-0303-7

A bromine-substituted hydrazone derivative, named N′-(4-bromobenzylidene)-2-hydroxybenzohydrazide (BBH), and its unsubstituted analogue, named N′-benzylidene-2-hydroxybenzohydrazide (BH), have been synthesized by a simple and effective one-pot synthesis method. Their interactions with human serum albumin (HSA) were comprehensively studied employing spectroscopy, electrochemistry, and molecular docking. Our attention was largely on the thermodynamic properties of their binding to HSA, in order to evaluate the impact of a bromine atom in BBH to its biological activity comparing to BH. BBH is a stronger ligand with a binding constant of 105 L·mol−1 and formed a more stable complex with HSA compared with BH. The binding processes of both BBH and BH are mainly an enthalpy driven process occurring in site I, mainly bound by hydrogen bonding and the van der Waals force.

Nd(III)-Induced Rice Mitochondrial Dysfunction Investigated by Spectroscopic and Microscopic Methods

Co-reporter:Cai-Fen Xia;Long Lv;Xin-You Chen;Bo-Qiao Fu

The Journal of Membrane Biology 2015 Volume 248( Issue 2) pp:319-326

Publication Date(Web):2015 April

DOI:10.1007/s00232-015-9773-1

The production capacity and yield of neodymium (Nd) in China have ranked the first in the world. Because of its unique biophysical and biochemical properties, Nd compounds have entered into the agricultural environment greatly to promote plant growth. Mitochondria play a crucial role in respiration and metabolism during the growth of plants. However, little is known about the mechanism by which Nd act at the mitochondrial level in plant cells. In this study, rice mitochondrial swelling, collapsed transmembrane potential and decreased membrane fluidity were examined to be important factors for mitochondria permeability transition pore (mPTP) opening induced by Nd(III). The protection of cyclosporin A (CsA) and dithiothreitol (DTT) could confirm that Nd(III) could trigger mPTP opening. Additionally, mitochondrial membrane breakdown observed by TEM and the release of cytochrome c (Cyt c) could also elucidate the mPTP opening from another point of view. At last, the study showed that Nd(III) could restrain the mitochondrial membrane lipid peroxide, so it might interact with anionic lipid too. This detection will be conductive to the safe application of Nd compounds in agriculture and food industry.

Spectroscopic and Microscopic Studies on the Mechanism of Mitochondrial Toxicity Induced by CdTe QDs Modified with Different Ligands

Co-reporter:Lu Lai;Jian-Cheng Jin;Zi-Qiang Xu;Yu-Shu Ge

The Journal of Membrane Biology 2015 Volume 248( Issue 4) pp:727-740

Publication Date(Web):2015 August

DOI:10.1007/s00232-015-9785-x

Quantum dots (QDs) are increasingly applied in sensing, drug delivery, biomedical imaging, electronics industries, etc. Consequently, it is urgently required to examine their potential threat to humans and the environment. In the present work, the toxicity of CdTe QDs with nearly identical maximum emission wavelength but modified with two different ligands (MPA and BSA) to mitochondria was investigated using flow cytometry, spectroscopic, and microscopic methods. The results showed that QDs induced mitochondrial permeability transition (MPT), which resulted in mitochondrial swelling, collapse of the membrane potential, inner membrane permeability to H+ and K+, the increase of membrane fluidity, depression of respiration, alterations of ultrastructure, and the release of cytochrome c. Furthermore, the protective effects of CsA and EDTA confirmed QDs might be able to induce MPT via a Ca2+-dependent domain. However, the difference between the influence of CdTe QDs and that of Cd2+ on mitochondrial membrane fluidity indicated the release of Cd2+ was not the sole reason that QDs induced mitochondrial dysfunction, which might be related to the nanoscale effect of QDs. Compared with MPA-CdTe QDs, BSA-CdTe QDs had a greater effect on the mitochondrial swelling, membrane fluidity, and permeabilization to H+ and K+ by mitochondrial inner membrane, which was caused the fact that BSA was more lipophilic than MPA. This study provides an important basis for understanding the mechanism of the toxicity of CdTe QDs to mitochondria, and valuable information for safe use of QDs in the future.

Low temperature synthesis of highly stable phosphate functionalized two color carbon nanodots and their application in cell imaging

Co-reporter:Zi-Qiang Xu, Li-Yun Yang, Xiao-Yang Fan, Jian-Cheng Jin, Jie Mei, Wu Peng, Feng-Lei Jiang, Qi Xiao, Yi Liu

Carbon 2014 Volume 66() pp:351-360

Publication Date(Web):January 2014

DOI:10.1016/j.carbon.2013.09.010

Phosphate functionalized carbon nanodots (C-dots) with satisfactory quantum yield have been prepared through one-step acidic oxidation of sucrose by H3PO4 at low temperature (60 °C). The as-prepared C-dots are monodisperse with narrow size distribution. Besides, two C-dots emitting different colors, namely green and yellow, can be easily separated by collecting the supernatant and precipitate after neutralization and centrifugation. Both C-dots show good photoluminescence properties over a very wide pH range (2.0–13.0). Moreover, they exhibit high tolerance to various external conditions, such as high ionic strength, external cations and UV excitation. The obtained C-dots can be internalized by cells without post surface passivation and they exhibit minimum toxicity as well as favorable biocompatibility. The highly stable, phosphate functionalized and two color C-dots with narrow size distribution are expected to have great potential application in bioimaging and bioanalysis.

Investigating the interactions of a novel anticancer delocalized lipophilic cation and its precursor compound with human serum albumin

Co-reporter:Jia Wang, Chen Xiang, Fang-Fang Tian, Zi-Qiang Xu, Feng-Lei Jiang and Yi Liu

RSC Advances 2014 vol. 4(Issue 35) pp:18205-18216

Publication Date(Web):26 Feb 2014

DOI:10.1039/C3RA46997B

F16 is a novel identified delocalized lipophilic cation (DLC) which has been found to inhibiting a variety of tumor cell proliferation due to its selective accumulation in the mitochondria of carcinoma cells. To gain further insight into the thermodynamic properties of this small molecule, we chose human serum albumin (HSA) as the model protein, and investigated the interactions of F16 and its precursor compound PVI with HSA by comprehensive spectroscopy, electrochemistry and molecule modeling methods. The static fluorescence quenching of HSA suggests that both F16 and PVI can form complexes with HSA, though the binding mechanisms are different. The main driving forces for F16–HSA binding are typical hydrophobic interactions, while PVI–HSA binding takes place through electrostatic interactions. F16–HSA binding shows an adverse temperature dependence recognized as the effect of the high activation energy requirement in the binding process generated by the specific structural obstacle. Both F16 and PVI can bind with HSA and thus benefit their transportation and elimination in body, however, the positive charge of F16 may have negative effect on the binding interaction.

Studies on the isolated mitochondrial damage induced by α-tocopheryl succinate and its interactions with human serum albumin

Co-reporter:Dong-Wei Li, Huan He, Bing-Bing Lin, Zi-Qiang Xu, Feng-Lei Jiang and Yi Liu

RSC Advances 2014 vol. 4(Issue 8) pp:3913-3919

Publication Date(Web):05 Dec 2013

DOI:10.1039/C3RA46172F

α-tocopheryl succinate (α-TOS), a redox-inactive vitamin E analogue, holds great promise for selectively triggering mitochondrial apoptosis in tumor cells. In this paper, in order to better understand the biophysical basis of α-TOS under biological conditions, the effects of α-TOS at high concentrations on the function of mitochondria and its interactions with human blood protein (human serum albumin, HSA) were investigated. We found that α-TOS with high concentration not only caused inhibition of mitochondrial respiration and mitochondrial permeability transition (MPT), but also strongly disturbed the mitochondrial membrane and ultrastructure. These results suggest that mitochondria are organelles that are very sensitive to α-TOS-induced stress, and the mechanism of damage to mitochondria may be due to MPT and impairing of the respiratory chain. In addition, it has been also demonstrated that α-TOS possesses moderate binding affinity to HSA in site I due to the formation of the α-TOS–HSA complex by hydrophobic, van der Waals and hydrogen bond forces. These results will help us learn more about biophysical properties of α-TOS at subcellular (mitochondria) and biomacromolecular (HSA) levels.

Multi-spectroscopic analysis and molecular modeling on the interaction of curcumin and its derivatives with human serum albumin: A comparative study

Co-reporter:Yu-Shu Ge, Cheng Jin, Zhe Song, Jia-Qi Zhang, Feng-Lei Jiang, Yi Liu

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2014 Volume 124() pp:265-276

Publication Date(Web):24 April 2014

DOI:10.1016/j.saa.2014.01.009

•Removing of methoxyl groups is benefit for binding on site II of HSA.•Demothxycurcumin influences the α-helix structure greater at low concentrations.•Bisdeoxycurcumin unfolds the protein more efficient at high concentrations.•Docking results explain the quenching behavior and preference of binding site.The comparative study about the interaction between curcumin and its derivatives (demothxycurcumin and bisdeoxycurcumin) with human serum albumin (HSA) has been carried out using multi-spectroscopic analysis and molecular modeling method. The characteristic of fluorescence quenching and the thermodynamic parameters have been studied by state emission fluorescence experiments under different temperatures with an interval of 6 K. Curcumin shows largest quenching constant and bisdeoxycurcumin shows the smallest at the temperature of 298 K. However, the quenching constant of curcumin drops quickly with the increase of temperature. Demothxycurcumin gives the largest quenching efficiency at the temperature of 310 K. An average distance of 6.7 nm for energy transfer has been determined based on förster resonance energy theory (FRET). The site competitive replacement experiments illustrate three compounds mainly binding on site I (Subdomain IIA) of the protein, and show tendency of binding on site II (Subdomain IIIA) with the removing of methoxyl groups. Circular dichroism spectra and Fourier transform infrared spectroscopy (FTIR) have been used to investigate the influence on protein secondary structure. Content of the α-helix increases at low concentrations of the compounds, while unfolding occurs at high concentrations. Docking simulation reveals possible mechanism for different quenching behavior and binding sites preferred by three compounds. The binding modes have effectively supported the conclusion of the experiments.Graphical abstract

An electrochemical and surface plasmon resonance study of adsorption actions of DNA by Escherichia coli

Co-reporter:Juan Zhang, Ran Li, Feng-Lei Jiang, Bo Zhou, Qing-Ying Luo, Qiu-Li-Yang Yu, Xiao-Le Han, Yi Lin, Hong He, Yi Liu, Yun-Long Wang

Colloids and Surfaces B: Biointerfaces 2014 Volume 117() pp:68-74

Publication Date(Web):1 May 2014

DOI:10.1016/j.colsurfb.2014.01.041

•A polypeptide RGD immobilization scheme for bacterial cells is described.•Binding process between E. coli and hsDNA investigated by electrochemical and SPR.•The two methods can be used to detect the DNA binding on microorganism surface.In this work, we proposed an immobilization scheme targeting Escherichia coli bacterial cells onto gold surface utilizing polypeptide RGD's binding specificity to gold particles. Adsorption kinetics of extracellular Herring Sperm DNA on E. coli was then studied using electrochemical methods along with surface plasmon resonance spectroscopy through this immobilization scheme. The adsorption equilibrium constants of DNA adsorbing to E. coli from electrochemical method and surface plasmon resonance spectroscopy, were (5.596 ± 0.462) × 105 L mol−1 and (1.24 ± 0.361) × 105 L mol−1, accordingly. Importantly, this is the first study that used an electrochemical method to express the adsorptive action of DNA by E. coli.

Investigation of nitroxoline-human serum albumin interactions by spectroscopic methods

Co-reporter:WanJu Zhang;XuJie Xiong;Fang Wang;Li Li;Yan Zhang

Science China Chemistry 2014 Volume 57( Issue 12) pp:1690-1695

Publication Date(Web):2014 December

DOI:10.1007/s11426-014-5230-8

Nitroxoline is a wide spectrum antibacterial and is one of the most important urinary antiseptics. The interaction between nitroxoline and human serum albumin (HSA) has been investigated systematically by fluorescence spectroscopy, synchronous fluorescence, three-dimensional fluorescence, CD spectroscopy and UV-Vis absorption spectroscopy. The results indicated that the quenching of HSA by nitroxoline was static. The corresponding thermodynamic parameters ΔH, ΔS and ΔG calculated according to van’t Hoff equation revealed that the intermolecular forces acting between nitroxoline and HSA were mainly hydrogen bonding and van der Waals forces. The conformational changes in the interaction were studied by synchronous fluorescence, CD spectroscopy and three-dimensional fluorescence spectra which showed changes in the microenvironment and conformation of HSA.

Exploiting the Role of Resveratrol in Rat Mitochondrial Permeability Transition

Co-reporter:Yue Zhang;Fangfang Tian;Qi Xiao;Yanjun Hu;Jiahan Li

The Journal of Membrane Biology 2013 Volume 246( Issue 5) pp:365-373

Publication Date(Web):2013 May

DOI:10.1007/s00232-013-9540-0

Resveratrol (RSV), a natural polyphenolic antioxidant, has been considered an anticarcinogenic agent as it triggers tumor cell apoptosis through activation of the mitochondrial pathway. In our study, the effects of RSV on mitochondria, especially on the mitochondrial permeability transition (MPT) process, were investigated by multiple methods. We found that RSV induced a collapse of membrane potential and matrix swelling related to MPT. We further demonstrated that Ca2+ was necessary for this RSV-induced MPT opening. In addition, RSV induced the inner membrane permeabilization to H+ and K+, the depression of respiration and changes in membrane fluidity. The results suggested that RSV-induced MPT was accompanied by mitochondrial dysfunction. But the prohibition on lipid peroxidation and different effects of low- and high-dose RSV on membrane fluidity and respiration showed that the interaction of RSV and the mitochondria could not be the result of a single simple mechanism.

Studies of the Interaction Between Ronidazole and Human Serum Albumin by Spectroscopic and Molecular Docking Methods

Co-reporter:Wanju Zhang;Xujie Xiong;Fang Wang;Yushu Ge

Journal of Solution Chemistry 2013 Volume 42( Issue 6) pp:1194-1206

Publication Date(Web):2013 July

DOI:10.1007/s10953-013-0027-5

Ronidazole (RNZ) is widely used for the therapeutic treatment of farmed animals and is suspected of being a human carcinogen and mutagen. The interaction between RNZ and human serum albumin (HSA) was investigated systematically by fluorescence spectroscopy, synchronous fluorescence, three-dimensional fluorescence, CD spectroscopy, UV–vis absorption spectroscopy and a molecular docking study. The results indicate that the probable quenching mechanism of HSA by RNZ is dynamic quenching. The corresponding thermodynamic parameters, such as ΔH, ΔS and ΔG, etc., were calculated according to the van’t Hoff equation. The results indicate that the forces acting between RNZ and HSA are mainly hydrogen bonds and van der Waals forces. The conformational changes in the interaction were studied by synchronous fluorescence, CD spectroscopy and three-dimensional fluorescence spectra. The results reveal that the microenvironment and conformation of HSA has been changed. A molecular modeling study further confirmed the binding mode obtained by the experimental studies.

Mitochondrial Dysfunction Induced by Honokiol

Co-reporter:Jia-Xin Dong;Guang-Yuan Zhao;Qiu-Li-Yang Yu;Ran Li

The Journal of Membrane Biology 2013 Volume 246( Issue 5) pp:375-381

Publication Date(Web):2013 May

DOI:10.1007/s00232-013-9543-x

Honokiol has shown the ability to induce the apoptosis of several different cancer cell lines. Considering that mitochondria are involved in apoptosis, the aim of the present work was to investigate the effects of honokiol on mitochondria. The effects of honokiol on the permeability of H+ and K+, membrane potential, membrane fluidity, respiration and swelling of mitochondria isolated from the rat liver were assessed. The results show that honokiol can significantly induce mitochondrial swelling, decrease membrane potential and affect the respiration of mitochondria. Meanwhile, honokiol does not have a direct effect on the mitochondrial permeability transition pore.

Synthesis of F16 conjugated with 5-fluorouracil and biophysical investigation of its interaction with bovine serum albumin by a spectroscopic and molecular modeling approach

Co-reporter:Chen Xiang;Dong-Wei Li;Zu-De Qi;Feng-Lei Jiang;Yu-Shu Ge

Luminescence 2013 Volume 28( Issue 6) pp:865-872

Publication Date(Web):

DOI:10.1002/bio.2447

ABSTRACT

5-Fluorouracil (5-FU) has been widely used as a chemotherapy agent in the treatment of many types of solid tumors. Investigation of its antimetabolites led to the development of an entire class of fluorinated pyrimidines. However, the toxicity profile associated with 5-FU is significant and includes diarrhea, mucositis, hand–foot syndrome and myelosuppression. In aiming at reducing of the side effects of 5-FU, we have designed and synthesized delocalized lipophilic cations (DLCs) as a vehicle for the delivery of 5-FU. DLCs accumulate selectively in the mitochondria of cancer cells because of the high mitochondrial transmembrane potential (ΔΨ_m). Many DLCs exhibited anti-cancer efficacy and were explored as potential anti-cancer drugs based on their selective accumulation in the mitochondria of cancer cells. F16, the DLC we used as a vehicle, is a small molecule that selectively inhibits tumor cell growth and dissipates mitochondrial membrane potential. The binding of the conjugate F16–5-FU to bovine serum albumin (BSA) was investigated using spectroscopic and molecular modeling approaches. Fluorescence quenching constants were determined using the Stern–Volmer equation to provide a measure of the binding affinity between F16–5-FU and BSA. The activation energy of the interaction between F16–5-FU and BSA was calculated and the unusually high value was discussed in terms of the special structural block indicated by the molecular modeling approach. Molecular modeling showed that F16–5-FU binds to human serum albumin in site II, which is consistent with the results of site-competitive replacement experiments. It is suggested that hydrophobic and polar forces played important roles in the binding reaction, in accordance with the results of thermodynamic experiments. Copyright © 2012 John Wiley & Sons, Ltd.

Ce(III)-Induced Rice Mitochondrial Permeability Transition Investigated by Spectroscopic and Microscopic Studies

Co-reporter:Cai-Fen Xia;Jie Zhao;Jian-Cheng Jin;Lian Yuan

Biological Trace Element Research 2013 Volume 152( Issue 2) pp:284-291

Publication Date(Web):2013 May

DOI:10.1007/s12011-013-9621-z

Cerium has been widely used as fertilizer and feed additives in agriculture, but it might finally impair human health by food chain accumulation with its dosage increased in environmental and crops samples. To resolve the conflict, we investigated the effects of Ce(III) on isolated rice mitochondrial permeability transition (MPT) by examining mitochondrial swelling, transmembrane potential, membrane fluidity with spectroscopy, and observing the mitochondrial ultrastructure, meanwhile, the interaction site(s) and mechanism between Ce(III) and mitochondria were also studied. The results showed that the low level of Ce(III) had little effect on rice MPT, however, the higher level of Ce(III) could induce rice MPT, and the thiol (−SH) groups of membrane proteins (defined as “S” site) matched by Ce(III)-triggered rice MPT pore opening.

Interaction between a cationic porphyrin and ctDNA investigated by SPR, CV and UV–vis spectroscopy

Co-reporter:Zi-Qiang Xu, Bo Zhou, Feng-Lei Jiang, Jie Dai, Yi Liu

Colloids and Surfaces B: Biointerfaces 2013 110() pp: 321-326

Publication Date(Web):

DOI:10.1016/j.colsurfb.2013.04.040

The adsorption of an anticancer hydrazone by protein: an unusual static quenching mechanism

Co-reporter:Fang-Fang Tian, Jia-Han Li, Feng-Lei Jiang, Xiao-Le Han, Chen Xiang, Yu-Shu Ge, Li-Li Li and Yi Liu

RSC Advances 2012 vol. 2(Issue 2) pp:501-513

Publication Date(Web):16 Nov 2011

DOI:10.1039/C1RA00521A

A novel hydrazone, 4-chloro-N′-(pyridin-2-ylmethylene)benzohydrazide (CPBH) has been synthesized through a one-pot synthesis method and used as a chemical probe to find the structural cause of the unusual static quenching mechanism in the interaction with serum albumin. The adsorption of CPBH by bovine/human serum albumin (BSA/HSA) has been investigated systematically by comprehensive spectroscopy, modeling, electrochemistry and microcalorimetry under physiological conditions. CPBH forms a complex with BSA/HSA with the binding site in Sudlow's site I of BSA/HSA. The adverse temperature dependence in the unusual static quenching is found to be a reasonable consequence of the large activation energy requirement in the binding process, which is required to overcome the structural block and it is a direct result of the unique microstructure of the binding pocket.

Toxicity of nano zinc oxide to mitochondria

Co-reporter:Jia-han Li, Xiao-rong Liu, Yue Zhang, Fang-fang Tian, Guang-yuan Zhao, Qiu-li-yang Yu, Feng-lei Jiang and Yi Liu

Toxicology Research 2012 vol. 1(Issue 2) pp:137-144

Publication Date(Web):26 Jun 2012

DOI:10.1039/C2TX20016C

Zinc oxide nanoparticles (ZnO NPs) are increasingly applied in a diverse array of industrial and commercial products. Therefore, it is urgently required to characterize their toxic behavior. ZnO NPs have been reported to induce toxic effects at the levels of the individual organism, tissue, cell and DNA. However, little is known about the potential impacts of ZnO NPs at a subcellular level. In the present work, we investigated the toxicity of ZnO NPs to the isolated rat liver mitochondria. We found that treatment of mitochondria with ZnO NPs resulted in collapse of mitochondrial membrane potential (Δψ), swelling, depression of respiration, inner membrane permeabilization to H+ and K+, alterations of ultrastructure, release of cytochrome c, generation of reactive oxygen species (ROS), and Zn2+ liberation from ZnO NPs. These results suggested that ZnO NPs can increase the inner membrane permeability and impair the respiratory chain, thus leading to energy dissipation, oxidative stress and even apoptosis. This putative mechanism helps us learn more about the toxicology of this nanomaterial.

Probing the adverse temperature dependence in the static fluorescence quenching of BSA induced by a novel anticancer hydrazone

Co-reporter:Jin-Qiang Tong, Fang-Fang Tian, Qing Li, Li-Li Li, Chen Xiang, Yi Liu, Jie Dai and Feng-Lei Jiang

Photochemical & Photobiological Sciences 2012 vol. 11(Issue 12) pp:1868-1879

Publication Date(Web):01 Aug 2012

DOI:10.1039/C2PP25162K

A novel hydrazone, 2-hydroxy-N′-(3-hydroxybenzylidene) benzohydrazide (HHB), has been designed, synthesized and characterized. HHB was designed to be an analogue of 311 and PIH with potential anticancer activity, and the IC50 towards HeLa cell was about 3.46 × 10−5 mol−1 L. The interactions of HHB with bovine serum albumin (BSA) had been investigated systematically by spectroscopy, electrochemistry, and molecular modeling under simulative physiological conditions. HHB bound BSA in the sub-domains IIA to form a ground-state complex, inducing the quenching of the intrinsic fluorescence emission, the change of absorption spectrum and the increase of electrical resistance of BSA. An adverse temperature dependence in the fluorescence quenching was detected and discussed to be a reasonable consequence of the big Ea requirement to overcome the obstructive amino acid residues in the entrance to the binding site, which were closely related to the natural structure of BSA and the molecular shape of HHB. The impact of metal ions, including Fe2+, Fe3+, Cu2+, Mg2+, Zn2+, Ca2+ and Al3+, towards the interactions of HHB and BSA has been investigated and they were found to affect the HHB–BSA interactions in a mild way.

Spectroscopic studies on the interactions between CdTe quantum dots coated with different ligands and human serum albumin

Co-reporter:Lu Lai, Chen Lin, Zi-Qiang Xu, Xiao-Le Han, Fang-Fang Tian, Ping Mei, Dong-Wei Li, Yu-Shu Ge, Feng-Lei Jiang, Ye-Zhong Zhang, Yi Liu

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2012 Volume 97() pp:366-376

Publication Date(Web):November 2012

DOI:10.1016/j.saa.2012.06.025

This paper investigates the interactions between human serum albumin (HSA) and CdTe quantum dots (QDs) with nearly identical hydrodynamic size, but capped with four different ligands (MPA, NAC, and GSH are negatively charged; CA is positively charged) under physiological conditions. The investigation was carried out using fluorescence spectroscopy, circular dichroism (CD) spectra, UV–vis spectroscopy, and dynamic light scattering (DLS). The results of fluorescence quenching and UV–vis absorption spectra experiments indicated the formation of the complex of HSA and negatively charged QDs (MPA-CdTe, NAC-CdTe, and GSH-CdTe), which was also reconfirmed by the increasing of the hydrodynamic radius of QDs. The Ka values of the three negatively charged QDs are of the same order of magnitude, indicating that the interactions are related to the nanoparticle itself rather than the ligands. ΔH < 0 and ΔS > 0 implied that the electrostatic interactions play predominant roles in the adsorption process. Furthermore, it was also proven that QDs can induce the conformational changes of HSA from the CD spectra and the three-dimensional fluorescence spectra of HSA. However, our results demonstrate that the interaction mechanism between the positively charged QDs (CA-CdTe) and HSA is significantly different from negatively charged QDs. For CA-CdTe QDs, both the static and dynamic quenching occur within the investigated range of concentrations. According to the DLS results, some large-size agglomeration also emerged.Graphical abstractThe interaction between negatively charged QDs and HSA is a adsorption behavior, which depends on the nanoparticle itself rather than the coating molecule. However, the adsorption of HSA onto the surface of positively charged QDs would result in the aggregation of nanoparticles.Highlights► The interaction between negatively charged QDs and HSA is a adsorption behavior. ► A protein corona comes into being on the surface of negatively charged QDs. ► The adsorption of HSA to the positively charged QDs results in the aggregation of QDs. ► The aggregation of QDs can act as the nuclei adsorbing larger amounts of proteins.

Spectroscopic and electrochemical studies on the interaction of an inclusion complex of β-cyclodextrin/fullerene with bovine serum albumin in aqueous solution

Co-reporter:Mei-Fang Zhang, Li Fu, Jia Wang, Zi-Qiang Xu, Feng-Lei Jiang, Yi Liu

Journal of Photochemistry and Photobiology A: Chemistry 2012 Volume 228(Issue 1) pp:28-37

Publication Date(Web):15 January 2012

DOI:10.1016/j.jphotochem.2011.11.009

The potential effect of human exposure to carbonaceous nanomaterials (e.g., fullerenes or their derivatives) in the environment has become a concern. In the current study, we report the interaction of one water-soluble fullerene with bovine serum albumin using spectroscopic and electrochemical methods under aqueous solutions. The novel supramolecular inclusion complex of the water-soluble fullerene (β-CD)2/C60 was synthesized and characterized. In the mechanism discussed, the spectroscopic methods such as fluorescence quenching and ultraviolet–visible absorption, proved that the fluorescence quenching of BSA by (β-CD)2/C60 was the result of the formation of (β-CD)2/C60–BSA complex and that the mechanism of quenching might be a static quenching procedure. The binding constants Ka, the number of binding sites n, and the corresponding thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures were calculated through fluorescence spectroscopy, then as an auxiliary method, the electrochemical impedance spectroscopy (EIS) experiments confirmed this conclusion. The results indicated that the electrostatic interactions play a major role in (β-CD)2/C60–BSA association. The circular dichroism spectra show the conformation change of the effect of (β-CD)2/C60 on the conformation of BSA, which was confirmed by the results of the three-dimensional fluorescence spectra. Site marker competitive experiments indicate that the binding of (β-CD)2/C60 to BSA primarily took place in site I. The distance r between donor (BSA) and acceptor ((β-CD)2/C60) was obtained according to fluorescence resonance energy transfer (FRET). This work aims to demonstrate the mechanisms of the formation of the complex between water-soluble fullerene and protein under physiological conditions, as well as the remediation for the possible unwarranted biological effects of water-soluble fullerene.Highlights► One water-soluble fullerene derivative (β-CD)2/C60 was synthesized and characterized. ► Various detection methods suggest the mechanism might be a static quenching. ► The electrostatic interactions play a major role in association. ► This study should help the understanding of how nanomaterials interact with proteins.

Binding of fullerol to human serum albumin: Spectroscopic and electrochemical approach

Co-reporter:Mei-Fang Zhang, Zi-Qiang Xu, Yu-Shu Ge, Feng-Lei Jiang, Yi Liu

Journal of Photochemistry and Photobiology B: Biology 2012 Volume 108() pp:34-43

Publication Date(Web):1 March 2012

DOI:10.1016/j.jphotobiol.2011.12.006

Spectroscopic, structural and thermodynamic properties of chlorpyrifos bound to serum albumin: A comparative study between BSA and HSA

Co-reporter:Xiao-Le Han, Fang-Fang Tian, Yu-Shu Ge, Feng-Lei Jiang, Lu Lai, Dong-Wei Li, Qiu-Liyang Yu, Jia Wang, Chen Lin, Yi Liu

Journal of Photochemistry and Photobiology B: Biology 2012 Volume 109() pp:1-11

Publication Date(Web):2 April 2012

DOI:10.1016/j.jphotobiol.2011.12.010

Chlorpyrifos (CPF) is a widely used organophosphate insecticide which could bind with human serum albumin (HSA) and bovine serum albumin (BSA). The binding behavior was studied employing fluorescence, three-dimensional fluorescence, Circular dichroism (CD) spectroscopy, UV–vis absorption spectroscopy, electrochemistry and molecular modeling methods. The fluorescence spectra revealed that CPF causes the quenching of the fluorescence emission of serum albumin. Stern–Volmer plots were made and quenching constants were thus obtained. The results suggested the formation of the complexes of CPF with serum albumins, which were in good agreement with the results from electrochemical experiments. Association constants at 25 °C were 3.039 × 105 mol L−1 for HSA, and 0.3307 × 105 mol L−1 for BSA, which could affect the distribution, metabolism, and excretion of pesticide. The alterations of protein secondary structure in the presence of CPF were confirmed by the evidences from UV and CD spectra. Site competitive experiments also suggested that the primary binding site for CPF on serum albumin is close to tryptophan residues 214 of HSA and 212 of BSA, which was further confirmed by molecular modeling.Graphical abstractThe crystallographic analysis reveals that the principal regions of ligand binding to HSA are located in hydrophobic cavities in subdomains IIA and IIIA, respectively. There is a large hydrophobic cavity present in subdomain IIA to which many drugs can bind to, including pesticide.Highlights► Some toxic mechanism of CPF at molecular lever was provided. ► The mechanism of quenching might be a static quenching procedure. ► The hydrogen bonds and van der Waals forces play a major role for association.

Synthesis of Three Novel Anionic Gemini Surfactants and Comparative Studies of Their Assemble Behavior in the Presence of Bovine Serum Albumin

Co-reporter:Yu-Shu Ge, Shu-Xin Tai, Zi-Qiang Xu, Lu Lai, Fang-Fang Tian, Dong-Wei Li, Feng-Lei Jiang, Yi Liu, and Zhi-Nong Gao

Langmuir 2012 Volume 28(Issue 14) pp:5913-5920

Publication Date(Web):March 16, 2012

DOI:10.1021/la204212s

Three novel anionic sulfonate gemini surfactants, sodium 4,4′-(10,19-dioxo-9,11,18,20-tetraazaoctacosane-9,20-diyl) dibenzenesulfonate (Surfactant I), sodium 4,4′-(12,21-dioxo-11,13,20,22-tetraazadotriacontane-11,22-diyl) dibenzenesulfonate (Surfactant II), and sodium 4,4′-(14,23-dioxo-13,15,22,24-tetraazahezatriacontane-13,24-diyl) dibenzenesulfonate (Surfactant III), with different lengths of hydrophobic tail have been synthesized, and their assembly behavior in the presence of bovine serum albumin (BSA) has been studied using spectral methods and molecular modeling methods at physiological pH and 298 K. Critical micelle concentrations (CMCs) of the three surfactants have been determined by surface tension measurements. Despite the obvious decrease of CMC with the increase of tail length, fluorescence spectra have shown much closer CAC in the presence of BSA. Surfactant II shows the highest CAC of 3.19 × 10–5 mol L–1 compared with the other two. The polarity of the microenvironment in BSA–surfactant systems has been investigated using pyrene as the probe. In addition, far-UV CD spectra studied the change of the secondary structure content of BSA caused by the three surfactants. The features of the assembly behavior were discussed by three concentration regions. Surfactant II could unfold the protein much more efficiently than the other two surfactants at low concentration, but at high concentration, the change of the secondary structure and the formation of hydrophobic microenvironment show a direct relationship to the length of the hydrophobic tail with the increase of the surfactant concentration.

A novel pH-sensitive (±)-α-tocopherol–5-fluorouracil adduct with antioxidant and anticancer properties

Co-reporter:Dong-Wei Li, Fang-Fang Tian, Yu-Shu Ge, Xin-Liang Ding, Jia-Han Li, Zi-Qiang Xu, Mei-Fang Zhang, Xiao-Le Han, Ran Li, Feng-Lei Jiang and Yi Liu

Chemical Communications 2011 vol. 47(Issue 38) pp:10713-10715

Publication Date(Web):05 Sep 2011

DOI:10.1039/C1CC13821A

A novel pH-sensitive (±)-α-tocopherol–5-fluorouracil (VE-5-FU) adduct with antioxidant and anticancer properties for antioxidant-based cancer chemoprevention was synthesized and utilized for selective drug release in the stomach.

BODIPY-based fluorescent probes for mitochondria-targeted cell imaging with superior brightness, low cytotoxicity and high photostability

Co-reporter:Tao Gao, Huan He, Rong Huang, Mai Zheng, Fang-Fang Wang, Yan-Jun Hu, Feng-Lei Jiang, Yi Liu

Dyes and Pigments (June 2017) Volume 141() pp:

Publication Date(Web):June 2017

DOI:10.1016/j.dyepig.2017.03.009

Two mitochondria-targeted fluorescent probes (TPP- and TEA-BODIPY) were rationally designed and easily synthesized. These probes can specifically stain mitochondria in living cells with superior brightness, low cytotoxicity and high photostability, thus are quite promising as mitochondrial tracking probes.Two BODIPY-based fluorescent probes can specifically stain mitochondria with superior brightness, low cytotoxicity and high photostability.

A novel pH-sensitive (±)-α-tocopherol–5-fluorouracil adduct with antioxidant and anticancer properties

Co-reporter:Dong-Wei Li, Fang-Fang Tian, Yu-Shu Ge, Xin-Liang Ding, Jia-Han Li, Zi-Qiang Xu, Mei-Fang Zhang, Xiao-Le Han, Ran Li, Feng-Lei Jiang and Yi Liu

Chemical Communications 2011 - vol. 47(Issue 38) pp:NaN10715-10715

Publication Date(Web):2011/09/05

DOI:10.1039/C1CC13821A

Active site-targeted carbon dots for the inhibition of human insulin fibrillation

Co-reporter:Q. Q. Yang, J. C. Jin, Z. Q. Xu, J. Q. Zhang, B. B. Wang, F. L. Jiang and Y. Liu

Journal of Materials Chemistry A 2017 - vol. 5(Issue 10) pp:NaN2018-2018

Publication Date(Web):2017/02/03

DOI:10.1039/C6TB02823C

Ultrasmall silver nanoclusters: Highly efficient antibacterial activity and their mechanisms

Co-reporter:Jian-Cheng Jin, Xiao-Juan Wu, Juan Xu, Bei-Bei Wang, Feng-Lei Jiang and Yi Liu

Biomaterials Science (2013-Present) 2017 - vol. 5(Issue 2) pp:NaN257-257

Publication Date(Web):2016/12/06