Recent progress in delivery systems for photosensitizers and anti-cancer photodynamic therapy / 药学学报

Photodynamic therapy (PDT) is a new modality for cancer therapy, which has been used in the clinical treatment for various tumors, such as skin cancer, bladder cancer and prostate cancer. Most photosensitizers have the disadvantages of hydrophobic, low bioavailability and the limited tumor targeting ability. The nanoscale delivery systems can improve the solubility of photosensitizers and enhance their accumulation at the tumor sites. The multifunctional nano-delivery systems are prepared in combination with other anti-tumor drugs to enhance the anti-tumor effect. In addition to addressing the issues of poor solubility and the insufficient tumor targeting ability, the nanoscale delivery systems need to improve the pharmacokinetic properties of photosensitizers, facilitating their rapid accumulation at the tumor sites and quick elimination in vivo, and reducing the skin phototoxicity. This review summarizes the recent clinical application of PDT of cancer, the development of photosensitizers, the delivery systems for photosensitizers and the combinatorial application with other therapeutic methods. The goal is to present an understanding of knowledge on the design of new types of photosensitizers and its clinical application in PDT of cancer.

Effect of micro/nanoscaled Ti phosphate/Ti oxide hybrid coating on the osseointegration of Ti implants / 华西口腔医学杂志

OBJECTIVES@#This study was performed to fabricate a bionic coating with titanium (Ti) phosphate to promote the osseointegration of Ti substrate implants.@*METHODS@#Phosphorylated micro/nanocoating was prepared on the surface of pure titanium (i.e., TiP-Ti) by hydrothermal process under special pressure, and the untreated smooth pure titanium (cp-Ti) was selected as the control. To evaluate the characteristics of the coating surface, scanning electron microscopy, X-ray diffraction, atomic force microscopy, and contact-angle measurement were performed. In addition, the effects of TiP-Ti on the proliferation, adhesion, and differentiation of rat bone marrow mesenchymal stem cells (BMSCs) were investigated by using @*RESULTS@#The TiP-Ti surface presented a bionic structure with coexisting nanoscale 3D spatial structure and microscale pores. @*CONCLUSIONS@#A bionic structure with TiP-Ti micro/nanoscale coating was successfully fabricated, indicating a promising method for modifying the surface of implants.

Self-assembly in the transparent droplets formed during the screening of protein self-assembly conditions / 生物工程学报

Protein self-assemblies at the micro- and nano-scale are of great interest because of their morphological diversity and good biocompatibility. High-throughput screening of protein self-assembly at different scales and morphologies using protein crystallization screening conditions is an emerging method. When using this method to screen protein self-assembly conditions, some apparently transparent droplets are often observed, in which it is not clear whether self-assembly occurs. We explored the interaction between β-lactoglobulin and the protein crystallization kit Index™ C10 and observed the presence of micro- and nano-scale protein self-assemblies in the transparent droplets. The diverse morphology of the micro- and nano-scale self-assemblies in the transparent droplets formed by mixing different initial concentrations of β-lactoglobulin and Index™ C10 was further investigated by scanning electron microscope. Self-assembly process of fluorescence-labelled β-lactoglobulin was monitored continuously by laser confocal microscope, allowing real-time observation of the liquid-liquid phase separation phenomenon and the morphology of the final self-assemblies. The internal structure of the self-assemblies was gradually ordered over time by in-situ X-ray diffraction. This indicates that the self-assembly phenomenon within transparent droplets, observed in protein self-assembly condition screening experiments, is worthy of further in-depth exploration.

Method of nanosized calcium salt ( calcite ) preparation based on the characterization of natural spar (calcite), fluorspar, feldspar / Монголын эм зүй, эм судлал

@#Calcium salt composite/calcite or spar is one of traditionally used therapeutic material for hard tissue repair and regeneration due to its abundant calcium content. There are several types of calcite (fluorspar or calcite fluoride, cobaltoan calcite, etc) exist in the nature and their therapeutic effects are different depending on their basic properties. For instance, calcium carbonate based calcite used to treat damaged hard tissue in the traditional medicine. Here, we would like to investigate characterizations of three different types of calcites gathered from the nature. For this purpose, collected calcium salt composites ( calcite, fluorspar, feldspar ) were examined their surface properties, morphology and size by the scanning electron microscopy. Energy-dispersive X-ray spectroscopy was used to determine their elemental analysis and X-ray diffraction was carried out to characterize their crystallinity structure. Based on the calcium contents, calcium carbonate-based calcite was selected to form nano-sized calcite and study their toxicity by using mesenchymal stem cell. Throughout this study, we identified properties of three different calcites and successfully reduced size in nanoscale which helps to use in the future treatment of osteoporosis or to stimulate osteogenesis.

Research progress in mechanical strength enhancement methods of jaw tissue engineering scaffolds / 口腔疾病防治

@#Bone tissue engineering, as an emerging method for the treatment of jaw defects caused by oral and maxillofacial trauma, inflammation, tumors and other diseases, has been a research hotspot due to its advantages of wide sources of materials, low risk of immune rejection and personalized treatment. However, due to functional activities such as chewing and expression in the oral and maxillofacial regions, the mechanical strength of scaffolds is highly required. A single component of scaffolds can not fully meet the requirements of oral and maxillofacial bone defect repair. In this paper, the methods of strengthening the mechanical strength of jaw bone tissue engineering scaffolds are summarized by summarizing the research on strengthening the mechanical strength of scaffolds in recent years. A review of the literature showed that, composite modification, crosslinking, coating, bionic scaffolding and other new processing methods have been used to enhance the mechanical strength of scaffolds. Among these studies, research on compound modification occurred the earliest. Although this process is simple, other substances have been introduced to increase the number of degradation products, and the compounding ratio needs to be adjusted. The crosslinking method has the risk of cytotoxicity due to the use of crosslinking agents; the coating method does not change the original structure and only changes the surface modification; however, it can be better utilized if the problem of stress concentration between interfaces is solved. Biomimetic scaffolds and microregulatory scaffolds are emerging technologies in recent years that can improve the internal molecular arrangement of materials, thus enhancing mechanical strength. Therefore, on the basis of perfecting the traditional method, future research will focus on new nanoscale materials, bionic scaffolds and new methods for the precise control of scaffold microstructure.

Strategies for enhancing nanoscale brain targeting drug delivery / 药学学报

The blood brain barrier can selectively block the uptake of xenobiotics from peripheral blood into the brain. Although this is important for maintaining the stability of the brain environment and normal function of the central nervous system, it presents a challenge for delivery of therapeutic drugs to the brain. Passive brain-targeting drug carrier is able to increase the drug concentration in the brain by enhancing the affinity to blood-brain barrier and/or inhibiting the efflux absorbed drug via P-glycoprotein. The active brain-targeting drug carrier can be obtained by linking specific ligands or antibodies onto passive target carriers to achieve precise delivery of drugs to the brain. Dual targeting drug carriers obtained by combining tumor cell targeting with brain targeting have shown their advantages for treatment of brain tumors. The targeted drug delivery to brain will provide a unique manner for the treatment of brain diseases such as Alzheimer's, Parkinson's, brain tumors, and stroke. Among the drug delivery systems of passive brain-targeting, active brain-targeting and dual brain-targeting, we evaluated the strategies to improve brain drug delivery efficiency, such as by reducing carrier size, opening tight junctions between cells at the blood-brain barrier, incorporating hydrophilic groups on the surface of the carrier, and alternative intranasal drug administration.

Site-targeted imaging enhancement of viable myocardium after ischemia-reperfusion by a novel nano-scale ultrasound contrast agent: a vivo study / 中华超声影像学杂志

Objective@#To prepare a kind of lipid nanoparticle ultrasound contrast agents with the ability to target to viable myocardium for diagnosis.@*Methods@#The agent was a biotinylated, fluorescent-labelled, lipid-coated, liquid perfluorocarbon emulsion. Physico-chemical properties of the agent were measured, including size distribution, Zeta Potential, concentration and so on. Ischemia-reperfusion models were created in rats, and then exposed to biotinylated anti-MCP-1 monoclonal antibody, rhodamine avidin and biotinylated, FITC-labelled nanoparticles, respectively. Echocardiography was taken before and after injection. Frozen sections of their hearts were observed under fluorescence microscope.@*Results@#The particle diameter, zeta potential and concentration of lipid nanoparticles were (172.30±52.06)nm, (-33.10±6.50)mV and (2.28±0.46)×1011/ml, respectively. From the short-axis view, the myocardium under endocardium of anterior wall was enhanced obviously. While myocardium of other walls were still. The lipid nanoparticles located in the myocardium of anterior wall and gave out bright green and red fluorescence under fluorescence microscope, while neither lipid nanoparticles nor fluorescence were found in other sites of ventricular myocardium.@*Conclusions@#The viable myocardium can be targeted and acoustically enhanced by the self-made nano-scale ultrasound contrast agent. This new agent has potential to improve sensitivity and specificity for noninvasive identifying viable myocardium.

Site‐targeted imaging enhancement of viable myocardium after ischemia‐reperfusion by a novel nano‐scale ultrasound contrast agent :a vivo study / 中华超声影像学杂志

Objective To prepare a kind of lipid nanoparticle ultrasound contrast agents with the ability to target to viable myocardium for diagnosis . Methods T he agent was a biotinylated ,fluorescent‐labelled ,lipid‐coated , liquid perfluorocarbon emulsion . Physico‐chemical properties of the agent were measured ,including size distribution ,Zeta Potential ,concentration and so on . Ischemia‐reperfusion models were created in rats ,and then exposed to biotinylated anti‐MCP‐1 monoclonal antibody ,rhodamine avidin and biotinylated ,FITC‐labelled nanoparticles ,respectively . Echocardiography was taken before and after injection . Frozen sections of their hearts were observed under fluorescence microscope . Results T he particle diameter ,zeta potential and concentration of lipid nanoparticles were ( 172 .30 ± 52 .06) nm ,( －33 .10 ± 6 .50) mV and ( 2 .28 ± 0 .46 ) × 1011/ml ,respectively . From the short‐axis view ,the myocardium under endocardium of anterior wall was enhanced obviously . While myocardium of other walls were still . T he lipid nanoparticles located in the myocardium of anterior wall and gave out bright green and red fluorescence under fluorescence microscope ,w hile neither lipid nanoparticles nor fluorescence were found in other sites of ventricular myocardium . Conclusions The viable myocardium can be targeted and acoustically enhanced by the self‐made nano‐scale ultrasound contrast agent . T his new agent has potential to improve sensitivity and specificity for noninvasive identifying viable myocardium .

Effects of Astragalus Polysaccharide on Mechanical Characterization of Liver Sinusoidal Endothelial Cells by Atomic Force Microscopy at Nanoscale / 中国结合医学杂志

<p><b>OBJECTIVE</b>To study the effects of Astragalus polysaccharide (APS), the primary effective component of the Chinese herb medicine Astragalus membranaceus (frequently used for its anti-hepatic fibrosis effects), on nanoscale mechanical properties of liver sinusoidal endothelial cells (SECs).</p><p><b>METHODS</b>Using endothelial cell medium as the control, 5 experimental groups were established utilizing different concentrations of APS, i.e. 12.5, 25, 50, 100, and 200 μg/mL. By using atomic force microscopy along with a microcantilever modified with a silicon dioxide microsphere as powerful tools, the value of Young's modulus in each group was calculated. SAS 9.1 software was applied to analyze the values of Young's modulus at the pressed depth of 300 nm. Environmental scanning electron microscopy was performed to observe the surface microtopography of the SECs.</p><p><b>RESULTS</b>The value of Young's modulus in each APS experimental group was significantly greater than that of the control group: as APS concentration increased, the value of Young's modulus presented as an increasing trend. The difference between the low-concentration (12.5 and 25 μg/mL) and high-concentration (200 μg/mL) groups was statistically significant (P<0.05), but no significant differences were observed between moderateconcentration (50 and 100 μg/mL) groups versus low- or high-concentration groups (P>0.05). Surface topography demonstrated that APS was capable of increasing the total area of fenestrae.</p><p><b>CONCLUSIONS</b>The values of Young's modulus increased along with increasing concentrations of APS, suggesting that the stiffness of SECs increases gradually as a function of APS concentration. The observed changes in SEC mechanical properties may provide a new avenue for mechanistic research of anti-hepatic fibrosis treatments in Chinese medicine.</p>

Preparation and characterization of restructured vesicles of grape-derived multicomponents for active peptides loading / 中草药

Objective To reconstruct the functional vesicles by using the components isolated from grapes, and investigate its properties of the loading of peptides. Methods Grape polyphenols (GP) were extracted by ethanol, and the extraction technology of GP was optimized by single factor and orthogonal experiments. GP was purified by macroporous resin adsorption and the purification technology. The preparation of GP and melittin (Mel) complexes (GPMC) were determined by orthogonal tests, and Sucrose density gradient centrifugation was used to extract grape-derived vesicles (GDVs) for loading complex GPMC to get GPMC-GDVs. The stability of GPMC-GDVs in PBS, DMEM, and 10% FBS were investigated. The cytotoxicity of GPMC and GPMC-GDVs on SMMC-7721 or HepG 2 cells was investigated by MTT method. Results The extraction process of GP was as follows: the extraction solvent was 60% ethanol solution, the heating temperature was 50 ℃, the solid-liquid ratio was 1:10, the extraction time was 50 min and extract 2 times. The purification conditions of GP were as follows: 4 mg/mL GP crude sample volume was 7 times of bed volume (BV), the washing dosage was 5 BV, and the elution volume of 60% ethanol was 5 BV. The preparation of GPMC-GDVs was as follows: 0.4 mg/mL GDVs was slowly dripped into GPMC solution with equal volume of Mel containing 2 mg/mL and incubated at room temperature for 30 min. As-prepared GPMC-GDVs had good stability in PBS, DMEM, and 10% FBS. The results of MTT method showed that GPMC-GDVs had a better tumor inhibitive effect. Conclusion By extracting the components of grape GP and GDVs and reorganizing the structures, the vesicles can be prepared for the loading of active melittin, which has a good application prospect in the field of delivery and anti-tumor effect of polypeptide drugs.

Effects of Non-ionic Polyacrylamide Alone or Combined with Nanoscale Silica Gel on the Stability of Glycyrrhetinic Acid Lipo-emulsion / 中国药房

OBJECTIVE:To investigate the effects of non-ionic polyacrylamide(model:NPAM 1400)alone or combined with nanoscale silica gel (nSiO2) on the stability of Glycyrrhetinic acid lipo-emulsion. METHODS:UV-spectrophotometer was used to determine absorbance of diluent at 500 nm before and after lipo-emulsion centrifugation. Using the preparation without stable excipient as blank,stability coefficient (KE) and it ratio (KE/KE blank) were calculated. Effects of different concentrations (200-600 mg/L) of non-ionic polyacrylamide on the stability of Glycyrrhetinic acid lipo-emulsion were evaluated. The optimal concentration of non-ionic polyacrylamide alone was determined primarily,and then the effects of it combined with different concentrations of hydrophilic nSiO2 (0.2％, 0.3％, 0.4％) or hydrophobic (0.2％, 0.3％, 0.5％) on the stability of Glycyrrhetinic acid lipo-emulsion were investigated. RESULTS:When adding non-ionic polyacrylamide alone,KE of Glycyrrhetinic acid lipo-emulsion mixed with 300 mg/L non-ionic polyacrylamide was the lowest,KE/KE blank was 0.22;when combined,KE of Glycyrrhetinic acid lipo-emulsion mixed with 300 mg/L non-ionic polyacrylamide and 0.2％ hydrophobic nSiO2 was the lowest,KE/KE blank was 0.27. CONCLUSIONS:Non-ionic polyacrylamide alone or combined with nSiO2 all can promote the stability of Glycyrrhetinic acid lipo-emulsion,among which 300 mg/L non-ionic polyacrylamide alone is the best.

Surface characterization of morphology and nano-scale adhesionforce on ethanol saturated root dentin / 西安交通大学学报(医学版)

Objective To observe the morphology of ethanol-wet dentin surfaces and detect their nano-scale adhesion force (Fad) by atomic force microscopy (AFM) in order to explore the potential mechanism of ethanol-wet bonding in improving clinical dentin bonding effectiveness.Methods Dentin slices from human premolar roots were prepared into flat ones, polished, and then randomly divided into five groups.All the specimens were acid-etched, rinsed, and left moist.They were then treated with 100％ ethanol for 0s (control group), 20s, 60s, 3×60s, or stepwise ethanol application.Afterwards, each group was scanned for the morphology in air and the Fad was probed by AFM.One-way ANOVA followed by Tukey`s test was employed for multiple comparisons using SPSS16.0.Results Compared with control group, ethanol-wet dentine produced a less undulating and relatively smooth surface topography.Ethanol-wet protocol significantly decreased the value of Fad in the experimental groups (P0.05).Conclusion When using AFM in air, ethanol-wet protocol with longer time can produce a less undulating and relatively smooth surface topography and decrease the Fad, whichindicates that the water saturated in dentin matrix was replaced more thoroughly by longer ethanol application time.This will benefit hydrophobicity of the dentin bonding interface.

Molecular dynamics simulation and analysis of BAFF which is incorporated with p-nitro-L-phenylalanine / 中国药科大学学报

In order to study the structure-function relationship in the protein which is incorporated with p-nitro-L-phenylalanine,the method of MD(Molecular Dynamics) simulation was established and successfully used in the analysis of protein which contains p-nitro-L-phenylalanine.The force field of CHARMM can only stimulate protein with natural amino acid in NAMD.Compared with phenylalanine,p-nitro-L-phenylalanine just has one more group of nitro.If the parameter of group of nitro was defined,the protein containing p-nitro-L-phenylalanine can be simulated.CGenFF-paramchem was used to calculate the energy and topological structure of p-nitro-L-phenylalanine' s new bonds (r),angles (θ),dihendrals (φ) and improper angle (ψ).And then the new defined parameter and topology information was input into the related parameter files and topology files in CHARMM.On the basis of correct parameter,NAMD can successfully simulate the modified BAFF(B lymphocyte stimulator) which contains p-nitro-L-phenylalanine.The changes in structure indicated that there might be new B cell epitopes.The temperature distribution of each frame in the process of dynamics stimulation was in accord with normal distribution,which proved the defined force field parameters was feasible.The RMSD of whole protein solution systemis 2.5.Calculate each resides' RMSF in BAFF,the RMSF of p-nitro-L-phenylalanine's residue is 3.7,which is obviously higher than that of the other residues in β-pleated sheet,and close to the loop rings,indicate that there might be variation in the area of p-nitro-L-phenylalanine residue and might produce new comformational epitopes.The results of MD stimulation will guide the immunogenicity experiments of p-nitro-L-phenylalanine modified proteins.

The design of non-viral nanometer vectors for delivery of small interfering RNA / 国际药学研究杂志

RNA interference(RNAi)is a method that allows double-stranded RNA(dsRNA)to induce the target gene mRNA to degrade in the body and lead to different levels of gene silencing. Small interfering RNA(siRNA)is the effector molecules of RNAi, and needs the delivery vehicle into the cells to play a therapeutic role. Nanoscale carrier can adjust the rate of drug release ,increase permeability of biofilm,change distribution in the body,and improve bioavailability. In this manuscript,materials,structure and bio?logical characteristics of existing non-viral nanometer vectors delivery for siRNA are summarized.

The design of non-viral nanometer vectors for delivery of small interfering RNA / 国际药学研究杂志

RNA interference (RNAi) is a method that allows double-stranded RNA (dsRNA) to induce the target gene mRNA to degrade in the body and lead to different levels of gene silencing. Small interfering RNA (siRNA) is the effector molecules of RNAi, and needs the delivery vehicle into the cells to play a therapeutic role. Nanoscale carrier can adjust the rate of drug release, increase permeability of biofilm, change distribution in the body, and improve bioavailability. In this manuscript, materials, structure and biological characteristics of existing non-viral nanometer vectors delivery for siRNA are summarized.

A Descriptive Study of Occupational Health Services in Self-employed Enterprises (Nanoscale Enterprises), Shiraz, Iran

BACKGROUND: This study was conducted with aim of providing an overview of the current status of occupational health services and identifying the most common harmful agents at workplaces of Iranian self-employed enterprises (Nano-Scale Enterprises). METHODS: A cross-sectional study was performed among a random sample including 1,758 employees engaging in self-employed enterprises with 5 and less employees. RESULTS: Coverage of occupational health surveillance was very poor, annual health examinations were been conducted only for 64 (3.64%) of males and 31 (1.76%) of females, and occupational health trainings were not included of the services at all. Personal Protective Equipment were available in 462 (26.3%) of the enterprises. only in 0.4% of the enterprises working processes were been equipped by a local exhaust ventilation system. Difficult postures were the most common (81.5%) adverse working conditions. CONCLUSION: This study revealed a poor level of the implementation of occupational health services in Iranian self-employed enterprises. Based on the findings, providing basic training on the occupational health, more enforcing in conduction of health examinations and providing PPE, and taking appropriate strategies aimed at eliminating or minimizing work environment harmful agents are the major factor that should be considered to improve the level of occupational health services among the studied enterprises.

Preparation and in vitro evaluation of pancreatic cancer-targeted nano-scale ultrasound contrast agent / 第二军医大学学报

Objective To prepare a pancreatic cancer-targeted nano-scale ultrasound contrast agent (T-UCA) and to evaluate its in vitro targeting effect. Methods PLGA-PEG-NHS was synthesized with poly(lactic-co-glycolic acid) (PLGA) , N hydroxysuccinimide (NHS) and polyethylene glycol (PEG). The construction of PLGA-PEG-NHS was characterized by1H NMR. Perfluoroctyl bromide (PFOB) loaded PLGA nanoparticle contrast agent was prepared using emulsion evaporation technique with PLGA-PEG-NHS and PFOB , and the products were further conjugated with Hedgehog antibody. The morphology of T-UCA were characterized by transmission electron microscopy , and the size distribution and Zeta potential of T-UCA were characterized by dynamic light scattering method. Furthermore , the drug entrapment efficiency and loading capacity of T-UCA were determined by OC-MS , and the release rate of T-UCA in vitro was examined by dialysis method. Finally , the in vitro targeting performance was quantitatively verified by fluorescence microscopy and flow cytometry with human pancreatic cancer lines SW1990 and CFPAC-1. Results The average diameter and the Zeta potential of T-UCA were 198. 9 nm and -31. 8 mV, respectively. Moreover , the encapsulation efficiency and drug loading of T-UCA was (63. 7 ± 3. 9) % and (14.3 ± 0.9)% , respectively. Nearly 85. 3% liquid perfluorocarbon was released from the T-UCA within 48 h. In vitro cell experiments showed that the targeted contrast agent could bind to SW1990 cells which had high expression of Hedgehog antigen , while not to the CFPAC-1 cells without expression of Hedgehog antigen Conclusion The emulsion evaporation technique can be used to prepare T-UCA with desirable characteristics, and the prepared T-UCA can specifically cancer cells with high expression of Hedgehog, making it a promising pancreatic cancer-targeted nanosacle ultrasound contrast agent.

Decontamination properties of nanoscale metal oxides against chemical warfare agents / 国际药学研究杂志

Objective To elevated the decontamination properties of commercial nanoscale metal oxides against chemical warfare agents (CWA), and provide more foundation for the satisfactory materials of CWA decontamination. Methods Some nanocrystals of commercial metal oxides such an MgO, TiO2, ZnO and zinc nickel ferrite compound had been chosen to compare their decontamination properties. The nanocrystals were mixed with three representative compounds, sulfur mustard (HD), soman (GD) and SI 2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) at room temperature and natural light. The analogous experiments were conducted without addition of nanocrystals as negative control. After a fixed time, the samples were then analyzed by the methods of T-135, Schoeneman reaction and conversion method to determine the content of CWA. The decontamination properties of nanocrystals were compared with negative control. Results The chosen nanoscale metal oxides excepted nanoscale MgO had good decontamination properties against HD, and they all could decontaminate GD quickly. Nanoscale TiO2 had superior decontamination properties against GD and HD. At the room temperature and natural light, HD was completely decontaminated within 20 hours and GD was completely decontaminated within 4 hours by nanoscale TiO2. The nanocrystals of metal oxides didn't decontaminate VX effectively. Compared to the activated clay group, nanoscale MgO had superior decontamination properties against VX over other nanocrystals (P<0.05), but the percentage of degradation was lower than 20% within 7 h. Conclusion The chosen nanoscale TiO2 has superior decontamination properties against GD and HD than others in natural condition, but it isn't a promising agent for the decontamination of VX.

Decontamination properties of nanoscale metal oxides against chemical warfare agents / 国际药学研究杂志

Objective To elevated the decontam ination properties of commercial nanoscale metal oxides against chemical warfare agents (CWA), and provide more foundation for the satisfactory materials of CWA decontamination. Methods Some nanocrystals of commercial metal oxides such an MgO, TiO2, ZnO and zinc nickel ferrite compound had been chosen to compare their decontamination properties. The nanocrystals were mixed with three representative compounds, sulfur mustard (HD), soman (GD) and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) at room temperature and natural light. The analogous experiments were conducted without addition of nanocrystals as negative control. After a fixed time, the samples were then analyzed by the methods of T-135, Schoeneman reaction and conversion method to determine the content of CWA. The decontamination properties of nanocrystals were compared with negative control. Results The chosen nanoscale metal oxides excepted nanoscale MgO had good decontamination properties against HD, and they all could decontaminate GD quickly. Nanoscale TiO2 had superior decontamination properties against GD and HD. At the room temperature and natural light, HD was completely decontaminated within 20 hours and GD was completely decontaminated within 4 hours by nanoscale TiO2. The nanocrystals of metal oxides didn′t decontaminate VX effectively. Compared to the activated clay group, nanoscale MgO had superior decontamination properties against VX over other nanocrystals (P<0.05), but the percentage of degradation was lower than 20% within 7 h. Conclusion The chosen nanoscale TiO2 has superior decontamination properties against GD and HD than others in natural condition, but it isn′t a promising agent for the decontamination of VX.

Synthesis of silver nanoparticles using a biosurfactant produced in low-cost medium as stabilizing agent

Background A biosurfactant produced by Pseudomonas aeruginosa cultivated in a low-cost medium formulated with 2.5% vegetable oil refinery residue and 2.5% corn steep liquor and distilled water was employed to stabilize silver nanoparticles in the liquid phase. The particles were initially synthesized using NaBH4 as reducing agent in biosurfactant reverse micelles and were extracted from the micellar solution to disperse in heptane. Results A silver particle size in the range of 1.13 nm was observed. The UV-vis absorption spectra proposed that silver nanoparticles could be formed in the reverse micelles and relatively stabilized for at least 3 months without passivator addition. The Transmission Electron Microscope (TEM) shows that the silver nanoparticles are of spherical form and relatively uniform. Conclusions This process provided a simpler route for nanoparticle synthesis compared to existing systems using whole organisms or partially purified biological extracts, showing that the low-cost biosurfactant can be used for nanoparticle synthesis as a non-toxic and biodegradable stabilizing agent.