In our work, rod-like SnO2 nanoparticles with tunable length have been successfully anchored onto graphene nanosheets through a simple and in situ hydrothermal strategy under acidic conditions. The SEM and TEM images demonstrate that the unique rod-like SnO2 nanoparticles with a diameter of 10–15 nm and length of 18–34 nm are uniformly anchored onto the surface of graphene nanosheets. Moreover, the particle sizes of rod-like SnO2 nanoparticles can be readily adjusted by simply varying the reaction temperature. Interestingly, with the increase of reaction temperature from 120 to 160 °C, the rod length of SnO2 nanoparticles significantly increased. More importantly, the SnO2@graphene products exhibit a very high specific surface area, which played a key role in maintaining the structural stability against the irreversible volume change during Li+ insertion/extraction. The nanocomposites show an extremely high lithium storage capability and an excellent cycling performance. The initial discharge capacities are 1284 mA h g−1 at current densities of 200 mA g−1. After 100 cycles, the discharge capacity still remains as high as 981 mA h g−1, indicating a superior retention capacity.

•A dual-templating route has been developed for synthesis of multi-shelled mesoporous silica nanoparticles (MMSNs).•The MMSNs display a spherical morphology, relatively uniform size distribution and good biocompatibility.•The Au-decorated MMSNs exhibit superior catalytic activity and good cycle stability for the reduction of 4-nitrophenol.•The MMSNs show high drug loading efficiency and the controlled pH-responsive release behavior for DOX.A facile vesicle-templating approach has been developed for synthesis of multi-shelled mesoporous silica nanoparticles (MMSNs) through a self-assembly of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS). The obtained MMSNs displayed a spherical morphology, relatively uniform size distribution with an average diameter of 185 nm and a good biocompatibility. Controlled experiments demonstrated that the morphology and structure of MMSNs were mainly determined by the mass ratio of CTAB/SDBS in the reagents. A possible growth mechanism of MMSNs was proposed based on TEM, SEM, and N2 sorption analysis, etc. Moreover, the Au-decorated MMSNs (Au@MMSNs) were constructed as the catalyst, which exhibited superior catalytic activity and good cycle stability for the reduction of 4-nitrophenol (4-NP). Additionally, the MMSNs also showed high drug loading efficiency and the controlled pH-responsive release behavior for doxorubicin hydrochloride (DOX). More importantly, the anticancer effect of DOX@MMSNs towards A549 cell further confirmed MMSNs could be employed as an ideal drug carrier. As a consequence, the MMSNs prepared are potential excellent candidates for various applications including nanoreactors, drug delivery, and cancer therapy.

Layered MoS2/reduced graphene oxide (MoS2/rGO) intercalation composites are synthesized via a SiO2-assisted hydrothermal method. This strategy discards addition of any amorphous carbon precursor for the synthesis of intercalation composites, and may reduce the defect degree and irreversible lithium storage sites in the final products. The structure and morphology characterization of the layered MoS2/rGO intercalation composites shows that the MoS2 composed of single layer or 2–4 layers display a highly exfoliated structure and disperse on the surface of graphene homogeneously and tightly, some of the interlayer spacing of MoS2 are enlarged, ranging from 0.7 to 1.17 nm with the intercalation of graphene. Electrochemical tests demonstrate that the MoS2/rGO-0.5 delivers a high reversible capacity of 1260.5 mA h g−1 in the initial cycle and retains 94.9% capacity after 50 cycles at 100 mA g−1. Furthermore, the capacity can reach 988.3 mA h g−1 even at a high current density of 1000 mA g−1. The excellent electrochemical performance of the MoS2/rGO intercalation composite could be attributed to the excellent match between the structure and morphology of layered MoS2 and graphene and the partial electron transfer from graphene to MoS2, which would maximize the synergistic interaction of the MoS2/rGO composite for reversible lithium storage.

Herein, we demonstrated two physical strategies, namely, vacuum heating and electron beam irradiation, to reinforce a nonmetallic photocatalyst, g-C3N4. These two post-treatments also improved the visible light absorption properties of g-C3N4; however, electron beam irradiation was more destructive, and it caused a determined change in the chemical bonds and band structure of the compound. According to the post-processing parameters mentioned in this article, vacuum heating (38 ± 2 mTorr for 4 days at 200 °C) enhanced the photocatalytic efficiency of the original g-C3N4 by 2.5 times, whereas electron beam irradiation (760 kGy at 1.8 MeV and 8 mA s−1) improved it by 4.5 times. Finally, the post-treated photocatalysts were stable during photocatalytic oxidation, which is important for practical applications.

In this work, a novel type of hollow mesoporous silica nanoparticle (HMSN) with a rough surface has been successfully prepared via a facile soft–hard template route by using a carbon nanosphere as a hard template and cetyltrimethylammonium bromide (CTAB) as a soft template, respectively. This method involves the preparation of a carbon nanosphere, sequential coating of double SiO2 layers, and the removal of the inner carbon core and CTAB to produce HMSNs. The obtained HMSNs possess spherical morphology, a mesoporous shell, and crumpled surfaces. The controlled experiments prove that the addition of 3-ammonia propyl triethoxy silane (APTES) is very crucial for the formation of desired HMSNs. The cell tests indicate that HMSNs show a good biocompatibility. As a result, the potential applications of HMSNs are further explored for drug delivery and protein adsorption, using doxorubicin hydrochloride (DOX) and Cytochrome c (Cyt c) as the model drug and protein, respectively. The HMSNs exhibit high drug loading and protein adsorption capacity, as well as the controlled pH-responsive release behavior for DOX. Therefore, the HMSNs prepared are ideal candidates for various applications such as nanoreactors, drug delivery and protein adsorption.

•A facile one-pot co-template synthesis route has been developed for the preparation of the peapod-like hollow carbon nanomaterials.•The hollow carbon materials possess high specific surface area, porous shell, uniform morphology, and controlled particle size.•The formation mechanism is discussed based on the experimental results.•The peapod-like hollow carbon nanomaterial exhibited ultrahigh drug loading capacity for doxorubicin hydrochloride (DOX).In this paper, peapod-like hollow carbon nanomaterial was fabricated via an efficient one-pot hydrothermal route. The carbon–silica composite was employed as the precursor and cetyltrimethylammonium bromide (CTAB) as the morphology-controlled agent. SEM and TEM results indicated that the carbon shell and the silica core in the precursor were not closely linked but rattle-type structure. After removing the silica template, the obtained carbon product had uniform peapod-like morphology, interconnected pores and high specific surface areas (above 800.0 m2/g). We found that CTAB played an important role in the formation of the products with peapod-like morphology. The particle sizes of the hollow carbon nanospheres were readily adjusted by varying the dosage of tetraethoxysilane (TEOS) and the volume ratio of ethanol and water. Based on the experimental results, the formation mechanism of the hollow carbon nanomaterial was also discussed. By virtue of their unique nanostructure and porous properties, the peapod-like hollow carbon nanomaterial exhibited ultrahigh drug loading capacity above 98.4% for doxorubicin hydrochloride (DOX).

•BBR could be reduced by eaq-.•BBR can react with OH through one-electron oxidation process.•BBR(–H) react with dGMP via electron transfer to give dGMP(–H).•BBR(–H) can selectively oxidize the DNA at guanine moiety.•The reaction mechanisms of BBR(–H) and 3BBR* with DNA were confirmed.In this paper, the photochemical and photobiological characters of the active radicals of berberine (BBR) was investigated for finding an efficient and safe photosensitizer with highly active transient products using in Photodynamic therapy (PDT) study. The active species of BBR was generated and identified by using pulse radiolysis method. In neutral aqueous solution, BBR react with hydrated electron and hydroxyl radical, forming the radical anion and neutral radical of BBR, and the related reaction rates were determined as 3.5 × 1010 and 6.7 × 109 M−1 s−1, respectively. Further, the capability of BBR to photosensitize DNA cleavage was testified by laser flash photolysis (LFP) method, the results demonstrated that BBR neutral radical could react with guanine mononucleotide (K = 1.9 × 109 M−1 s−1) via electron transfer to give the guanine neutral radical. Additionally BBR selective cleavage single and double strand DNA at guanine moiety was observed. Finally, combining with the thermodynamic calculation, the possible photodamage mechanism of dGMP and DNA induced by BBR was clarified.Graphical abstract

Nanocomposites have significant potential in the development of advanced materials for numerous applications. Tin dioxide (SnO2) is a functional material with wide-ranging prospects because of its high electronic mobility and wide band gap. Graphene as the basic plane of graphite is a single atomic layer two-dimensional sp2 hybridized carbon material. Both have excellent physical and chemical properties. Here, SnO2 quantum dots/graphene composites have been successfully fabricated by a facile ultrasonic method. The experimental investigations indicated that the graphene was exfoliated and decorated with SnO2 quantum dots, which was dispersed uniformly on both sides of the graphene. The size distribution of SnO2 quantum dots was estimated to be ranging from 4 to 6 nm and their average size was calculated to be about 4.8 ± 0.2 nm. This facile ultrasonic route demonstrated that the loading of SnO2 quantum dots was an effective way to prevent graphene nanosheets from being restacked during the reduction. During the calcination process, the graphene nanosheets distributed between SnO2 nanoparticles have also prevented the agglomeration of SnO2 nanoparticles, which were beneficial to the formation of SnO2 quantum dots.

Results on Al-induced crystallization of amorphous Ge (a-Ge) deposited by vacuum thermal evaporation techniques under thermal annealing in N2 atmosphere are presented in detail. The a-Ge crystallization and fractal Ge pattern formation on the free surface of annealed Al/Ge bilayer films deposited on single-crystal Si (100) substrates were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive X-ray spectrometry (EDS), and Raman spectra. It is found that the temperature field effects play an extremely crucial role in a-Ge crystallization and fractal Ge formation process. The open branched structure of fractal Ge clusters in Al/Ge bilayer films was effectively prepared by Al-induced crystallization when they were annealed at 400 °C for 60 min. These films with fractal Ge clusters exhibit charming noninteger dimensional nanostructures, which differ from those of conventional integer dimensional materials such as one-dimensional nanowires/nanorods, nanotubes, nanobelts/nanoribbons, two-dimensional heterojunctions, thin films, and zero-dimensional nanoparticles. The SEM image shows that a big Al grain was found located near the center of a fractal Ge cluster after the films were annealed at 400 and 500 °C for 60 min. This suggests that the grain boundaries of polycrystalline Al films are the initial nucleation sites of a-Ge. It also validates the preferred nucleation theory of a-Ge at triple-point grain boundaries of polycrystalline Al at the interface. This discovery may be explained by the metal-induced nucleation (MIN) mechanism.

In this paper, three-dimensional flower-like ZnO hierarchical nanostructures were fabricated from the thermal-decomposition of 3D zinc hydroxide carbonate precursor, which was synthesized by a urea hydrothermal method with block copolymer F127 (EO106-PO70-EO106) as the morphology director. XRD, IR, UV-vis, SEM, TEM, TG and N2 adsorption–desorption isotherms have been employed to characterize the products. The influences of synthesis parameters such as reaction time, the type of zinc sources, and species concentration on the morphologies of the products were systematically studied. It was found that the reaction time played a key role in determining the final morphology of porous ZnO. On the basis of experimental results, a possible formation mechanism of the 3D flower-like ZnO hierarchical nanostructures was discussed. More importantly, the gas sensing tests indicated that the sensor made from porous ZnO hierarchical nanostructures exhibited better gas sensing properties to n-butanol compared with the sensor based on the commercial ZnO nanoparticles. The enhancement in gas sensing properties was attributed to their unique 3D hierarchical nanostructures, high surface areas, and greater number of surface active sites.

A facile solvothermal process combined with a precursor thermal transformation method has been developed for preparing porous TiO2 hollow nanospheres with a high surface area and a good thermal stability. The porous TiO2 hollow spheres were obtained by using TiOSO4 as a titanium source and carbon nanospheres as a sacrificial template. Their particle size, diameter and morphology can be readily controlled by varying growth parameters, including reaction temperature, time and reagent concentration. The calcination temperature of TiO2–C core-shell nanospheres was found to have a profound effect on the structure and properties of the final products. The photocatalytic activities of the products were evaluated by the photodegradation of methyl orange (MO). The TiO2 hollow spheres obtained from 450 °C thermal treatment exhibited higher photocatalytic activity than commercial Degussa P25 in the presence of Cr(VI). The possible photodegradation mechanism was also investigated.

In this work, SnO2 hierarchical nanostructures were successfully prepared via a simple and surfactant-free hydrothermal process starting from stannous sulfate (SnSO4) and trisodium citrate dihydrate (Na3C6H5O7·2H2O) in a suitable ethanol–water system. TEM and HRTEM images showed that the obtained SnO2 products are uniform, well-dispersed, and have spherical architectures, composed of tiny primary nanocrystals, and the diameters are about 50 nm. It was found that the amount of Na3C6H5O7·2H2O and the volume ratio of ethanol and water played important roles in determining the final morphologies of the products. The gas sensing results indicated that the sensor made from porous SnO2 nanostructures calcined at 400 °C exhibited excellent gas sensing performance to butanol at the low temperature compared with those under higher calcination temperature and commercial SnO2. The SnO2 hierarchical nanostructures possess uniform size and large surface areas, making them ideal candidates for more potential applications such as battery electrodes and as opto-electronic devices.

In the present paper, the interaction between model protein lysozyme (Lys) and antitumorigenic berberine (BBR) was investigated by spectroscopic methods, for finding an efficient and safe photosensitizer with highly active transient products using in photodynamic therapy study. The fluorescence data shows that the binding of BBR could change the environment of the tryptophan (Trp) residues of Lys, and form a new complex. Static quenching is the main fluorescence quenching mechanism between Lys and BBR, and there is one binding site in Lys for BBR and the type of binding force between them was determined to be hydrophobic interaction. Furthermore, the possible interaction mechanism between BBR and Lys under the photoexcitation was studied by laser flash photolysis method, the results demonstrated that BBR neutral radicals (BBR(-H)•) react with Trp (K = 3.4 × 109 M−1 s−1) via electron transfer to give the radical cation (Trp/NH•+) and neutral radical of Trp (TrpN•). Additionally BBR selectively oxidize the Trp residues of Lys was also observed by comparing the transient absorption spectra of their reaction products. Through thermodynamic calculation, the reaction mechanisms between 3BBR∗ and Trp or Lys were determined to be electron transfer process.Graphical abstractThe possible photooxidation mechanisms of Trp and Lys caused by BBR. In the oxygen-free polar solvent, the photo-induced active radicals of BBR (BBR•+/BBR(-H)• and 3BBR∗) can oxidize Trp and Lys directly via an electron transfer mechanism (Type I mechanism). In the presence of O2, the photooxidation Lys involves both Type I and II processes, and Type I mechanism is competitive with 1O2. Which reaction is major pathway is dependent on the concentrations of O2 and the polar of the solvent.Highlights► Static quenching is the main fluorescence quenching mechanism between Lys and BBR, and there is one binding site in Lys for BBR. ► BBR neutral radical react with Trp (K = 3.4 × 109 M−1 s−1) via electron transfer to give the radical cation (Trp/NH•+) and neutral radical (TrpN•) of Trp. ► BBR can selectively oxidize the Trp residues of Lys with the rate constant 4.2 × 108 M−1 s−1. ► Through thermodynamic calculation, the reaction mechanisms between 3BBR∗ and Trp or Lys were determined to be electron transfer process.

A mixed-solvothermal method starting from dithizone as a slow release source was developed for synthesizing ZnxCd1−xSy photocatalysts with high visible light photocatalytic activities. XRD, TEM, SEM, XRF, BET, UV-Vis DR, Raman and PL spectra were employed to characterize the crystal phases, morphologies, chemical compositions and optical properties of the obtained products. Interestingly, the released zinc ions could form nanoparticles on the surface of nanorods and the excessive growth of sulfur could bring some new optical properties. The visible light photocatalytic properties of the products were also evaluated by photocurrent measurements in steady state conditions. The results indicated that ZnxCd1−xSy, especially Cd0.78Zn0.22S0.94, exhibited excellent photocatalytic activities, about 10 times higher than the commercial CdS and about 5 times higher than the typical CdS QDs. As a result, a possible mechanism was proposed to explain the formation of the ZnxCd1−xSycatalysts.

Chrysanthemum-like mesoporous silica nanoparticles (MSNs) with large surface areas were successfully synthesized in the presence of ethyl ether by a facile two-step method under mild conditions. Pyrene was chosen to evaluate their drug loading and controlled release properties. The results showed that prepared MSNs exhibited excellent release rate.

A wide range of pharmaceutical compounds have been identified in the environment, and their existence is a topic of growing concern, both for human and ecological health. The work described here has investigated the photolytic properties of L(+)-α-phenylglycine (L-α-PG-H) in aqueous solution as it can be degraded by photo-catalysis. In 266 nm laser flash photolysis of aqueous solution of L-α-PG-H saturated with nitrogen, two transient absorption bands are observed at 280–330 nm and 450–800 nm, respectively, due to L-α-PG-H radical cation and hydrated electrons (eaq−). Then eaq− reacts with L-α-PG-H to form the L-α-PG-H radical anion. Decaying rate constants of eaq− observed at 720 nm is to be 8.9 × 108 dm3 mol−1 s−1. The rate constant for oxidation of L-α-PG-H by SO4− is calculated as 4.5 × 108 and 4.3 × 108 s−1 mol−1 dm3, respectively. The dissociation constants (pKa) of L-α-PG-H is 3. Excited triplet of L-α-PG-H in solution is formed by laser flash photolysis. The quench rate constant of L-α-PG-H excited triplet (ks) is determined to be 1.3 × 107 dm3 mol−1 s−1 and k0 is equal to 1.7 × 105 s−1.

Spleen is an important immune organ and a constituting part of the reticuloendothelial system (RES). CNTs in vivo can be readily scavenged from blood and mainly entrapped by liver, spleen and lungs. Herein, water soluble multi-walled carbon nanotubes (S-MWCNTs) were used as a model to investigate the possible toxicity of carbon nanotubes (CNTs) to mouse spleen. The toxicity of various doses of S-MWCNTs was examined by carbon clearance measurement, oxidative stress assay, histopathologic and electron-microscopic examination. Compared with the control group, phagocytic activity of RES, activity of reduced glutathione, superoxide dismutase and malondialdehyde in splenic homogenate did not change significantly in 2 months. The histopathologic examination showed no observable sign of damage in spleen; however, the accumulated S-MWCNTs gradually transferred from the red pulp to the white pulp over the exposure time and might initiate the adaptive immune response of spleen.

Core-shell LiFePO4@C composites were synthesized successfully from FePO4/C precursor using the polyvinyl alcohol (PVA) as the reducing agent, followed by a chemical vapor deposition (CVD) assisted solid-state reaction in the presence of Li2CO3. Some physical and chemical properties of the products were characterized by X-ray powder diffraction (XRD), Raman, SEM, TEM techniques. The effect of morphology and electrochemical properties of the composites were thoroughly investigated. XRD patterns showed that LiFePO4 has an order olivine structure with space group of Pnma. TEM micrographs exhibited that the LiFePO4 particles encapsulated with 3-nm thick carbon shells. The powders were homogeneous with grain size of about 0.8 μm. Compared with those synthesized by traditional organic carbon source mixed method, LiFePO4@C composite synthesized by CVD method exhibited better discharge capacity at initial 155.4 and 135.8 mAh g−1 at 0.1C and 1C rate, respectively. It is revealed that the carbon layer coated on the surface of LiFePO4 and the amorphous carbon wrapping and connecting the particles enhanced the electronic conductivity and rate performances of the cathode materials.

Titania nanotubes (TiO2-NTs) are a potential drug vehicle for use in nanomedicine. To this end, a preliminary study of the interaction of a model cell with TiO2-NTs has been carried out. TiO2-NTs were first conjugated with a fluorescent label, fluorescein isothiocyanate (FITC). FITC-conjugated titania nanotubes (FITC-TiO2-NTs) internalized in mouse neural stem cells (NSCs, line C17.2) can be directly imaged by confocal microscopy. The confocal imaging showed that FITC-TiO2-NTs readily entered into the cells. After co-incubation with cells for 24 h, FITC-TiO2-NTs localized around the cell nucleus without crossing the karyotheca. More interestingly, the nanotubes passed through the karyotheca entering the cell nucleus after co-incubation for 48 h. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were also employed in tracking the nanotubes in the cell. These results will be of benefit in future studies of TiO2-NTs for use as a drug vehicle, particularly for DNA-targeting drugs.

Applications of atomic force microscopy (AFM) to the fabrication of chemical nanosensors are presented in this paper. Using AFM cantilever as cathode, the surface of Ti thin film is oxidized to form a few tens of nanometers wide oxidized metal semiconductor wire, which works as a nanowire-based hydrogen sensor. The reaction mechanism is proposed. The AFM observations of fabrication of a TiO2 nanowire are carried out. The sensitive characteristic of such TiO2 nanowires to hydrogen is investigated.

Lead zirconate titanate (PZT) films have been extensively investigated for many applications: the nonvolatile memory devices based on their remarkable ferroelectric properties, the microelectromechanical system (MEMS) based on their piezoelectricity as well in sensors as in actuators. In this paper, we inject charges into PZT thin films, and then the charge storage and transportation through PZT thin films were observed by electric force microscopy (EFM). Results were studied and charging mechanisms were proposed.

In this paper, the effects of electron beam irradiation on the gas sensing performance of tin dioxide thin films toward H2 are studied. The tin dioxide thin films were prepared by ultrasonic spray pyrolysis. The results show that the sensitivity increased after electron beam irradiation. The electron beam irradiation effects on tin dioxide thin films were simulated and the mechanism was discussed.

Chrysanthemum-like mesoporous silica nanoparticles (MSNs) with large surface areas were successfully synthesized in the presence of ethyl ether by a facile two-step method under mild conditions. Pyrene was chosen to evaluate their drug loading and controlled release properties. The results showed that prepared MSNs exhibited excellent release rate.

In this work, a novel type of hollow mesoporous silica nanoparticle (HMSN) with a rough surface has been successfully prepared via a facile soft–hard template route by using a carbon nanosphere as a hard template and cetyltrimethylammonium bromide (CTAB) as a soft template, respectively. This method involves the preparation of a carbon nanosphere, sequential coating of double SiO2 layers, and the removal of the inner carbon core and CTAB to produce HMSNs. The obtained HMSNs possess spherical morphology, a mesoporous shell, and crumpled surfaces. The controlled experiments prove that the addition of 3-ammonia propyl triethoxy silane (APTES) is very crucial for the formation of desired HMSNs. The cell tests indicate that HMSNs show a good biocompatibility. As a result, the potential applications of HMSNs are further explored for drug delivery and protein adsorption, using doxorubicin hydrochloride (DOX) and Cytochrome c (Cyt c) as the model drug and protein, respectively. The HMSNs exhibit high drug loading and protein adsorption capacity, as well as the controlled pH-responsive release behavior for DOX. Therefore, the HMSNs prepared are ideal candidates for various applications such as nanoreactors, drug delivery and protein adsorption.