The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of th...The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were char-acterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of glucose at the MoOx/AuNPs composite film was inves-tigated and analyzed in detail. It was shown that the MoOx/AuNPs composite was of strong electrocatalytic activity towards oxidation of glucose as well as other saccharides, so that an attempt was made for direct voltammetric determination of glucose. Then the positive scan polarization reverse catalytic voltammetry was proposed for the first time. Based on this method, the pure oxidation current was extracted by subtraction of the blank current in the reverse scan. The current sensitivity was enhanced tremendously and the signal to noise ra-tio was improved adequately. The electrocatalytic oxidation of glucose at the MoOx/AuNPs modified electrode was performed in alkaline medium, a wide linear range from 0.01 mmol/L to 4.0 mmol/L of glucose, a higher current sensitivity of 2.35 mA/（mmol/L·cm2）, and a lower limit of detection of 9.01 μmol/L （at signal/noise=3） were achieved. In addition, the electrocatalytic oxidation of other saccharides such as lactose, fructose and sucrose was also evaluated.展开更多
Here we developed a saccharic colorimetric method based on the combination of chemoselective ligation and enzyme-specific catalysis using aminooxy/ hydrazine-functionalized gold nanoparticles （AO/AuNPs or H/AuNPs）. ...Here we developed a saccharic colorimetric method based on the combination of chemoselective ligation and enzyme-specific catalysis using aminooxy/ hydrazine-functionalized gold nanoparticles （AO/AuNPs or H/AuNPs）. In the detection of galactose （Gal）, galactohexodialdose （GHDA）, the galactose oxidase （GalOx）-catalyzed product, has an aldehyde group, which allows it to chemoselectively react with an aminooxy or hydrazine group at the outer layer of AO/AuNPs or H/AuNPs by oxime/hydrazone click chemistry to form oxime or hydrozone. Consequent134 through the specific recognition of 1,4-phenylenediboronic acid （PDBA） on cis-diols, GHDA, which contains two pairs of hydroxyls in the cis form, can bind not only with AO/AuNPs or H/AuNPs, but also with PDBA to form boronate diester, thereby triggering the aggregation of AuNPs and causing the corresponding color change. As GalOx catalyzed specific substrates, the amount of Gal correlated with the production of GHDA and the extent of AuNPs aggregation, thus allowing a simple and easily operatable colorimetric method for Gal detection to be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 617 nm to that at 536 nm vary linearly with the logarithmic values of Gal concentrations within a wide range of 500 nM to 5 mM. Moreover, this colorimetric method shows anti-interference capability and high sensitivity with a detection limit of 21 nM. Thus, a universal platform for accurate and specific colorimetric analysis can be established through the integration of chemoselective ligation with enzyme specific catalysis.展开更多
The interaction of nanoparticles with proteins is extremely complex, important for understanding the biological properties of nanomaterials, but is very poorly understood. We have employed a combinatorial library of s...The interaction of nanoparticles with proteins is extremely complex, important for understanding the biological properties of nanomaterials, but is very poorly understood. We have employed a combinatorial library of surface modified gold nanoparticles to interrogate the relationships between the nanoparticle surface chemistry and the specific and nonspecific binding to a common, important, and representative enzyme, acetylcholinesterase （ACHE）. We also used Bayesian neural networks to generate robust quantitative structure-property relationship （QSPR） models relating the nanoparticle surface to the AChE binding that also provided significant understanding into the molecular basis for these interactions. The results illustrate the insights that result from a synergistic blending of experimental combinatorial synthesis and biological testing of nanoparticles with quantitative computational methods and molecular modeling.展开更多
A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a...A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a-D-glucopyranoside （pAPG）, which may induce aggregation of pAPG-functionalized gold nano- particles （AuNPs） to achieve color change of the test solution. Because pAPG is the substrate of α-glucosidase, the aggregation of AuNPs will be influenced by α-glucosidase since there is no coordination reactivity between PDBA and 4-aminobenzene, the hydrolyzed product of pAPG catalyzed by the enzyme. Therefore, a simple and easily-operated colorimetric method for the assay of a-glucosidase activity can be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 650 nm to that at 520 nm vary linearly with the α-glucosidase activity within a range from 0.05 to 1.1 U/mL with a lowest detection limit of 0.004 U/mL. Moreover, using the proposed method, the inhibition effect of gallic acid and quercetin on a-glucosidase activity can be tested with IC50 values of 1.16 mM and 1.82 μM, respectively. Thus, the method has a great potential not only for the detection of a-glucosidase activity, but also for the screening of its inhibitors.展开更多
Platinum nanoparticles （NPs） are reported to mimic various anfioxidant enzymes and thus may produce a positive biological effect by reducing reactive oxygen species （ROS） levels. In this manuscript, we report Pt N...Platinum nanoparticles （NPs） are reported to mimic various anfioxidant enzymes and thus may produce a positive biological effect by reducing reactive oxygen species （ROS） levels. In this manuscript, we report Pt NPs as an enzyme mimic of ferroxidase by depositing platinum nanodots on gold nanorods （Au@Pt NDRs）. Au@Pt NDRs show pH-dependent ferroxidase-like activity and have higher activity at neutral pH values. Cytotoxicity results with human cell lines （lung adenocarcinoma A549 and normal bronchial epithelial cell line HBE） show that Au@Pt NDRs are taken up into cells via endocytosis and translocate into the endosome/lysosome. Au@Pt NDRs have good biocompatibility at NDR particle concentrations lower than 0.15 nM. However, in the presence of H202, lysosome- located NDRs exhibit peroxidase-like activity and therefore increase cytotoxicity. In the presence of FeE＋, the ferroxidase-like activity of the NDRs protects cells from oxidative stress by consuming H202. Thorough consideration should be given to this behavior when employinK Au@Pt NDRs in biological svstems.展开更多
Pancreatic cancer is a devastating malignant disease with 5-year survival rate less than 8%.The impenetrable desmoplastic stroma of pancreatic tissue and serious side-effects of existing drugs hinder the effective tre...Pancreatic cancer is a devastating malignant disease with 5-year survival rate less than 8%.The impenetrable desmoplastic stroma of pancreatic tissue and serious side-effects of existing drugs hinder the effective treatment for pancreatic carcinoma.Thus,it is imperative to exploit much more safe and efficient methods to prolong the survival of pancreatic cancer patients.In this study,we explored a superior anti-pancreatic cancer strategy based on gadofullerene nanoparticles(GFNPs)using an orthotopic human pancreatic carcinoma(PANC-1)tumor model.It was demonstrated that GFNPs could efficiently suppress orthotopic pancreatic cancer in a dose manner,and significantly extend the survival rate of tumor-bearing mice.Of note,the proteomic profiling of tumor tissues revealed that GFNPs ameliorated the coagulation cascade dysfunction and downregulated the thrombin expression in pancreatic tumor tissues.The regulation of abnormal thrombin by GFNPs was validated in vitro and in vivo.More importantly,GFNPs suppressed orthotopic pancreatic cancer with negligible adverse effects,superior to the widely recognized clinical antipancreatic cancer drug,gemcitabine.Together,this study provides a promising therapeutic for intractable pancreatic cancer as well as a potential to alleviate the cancer-associated thromboembolic diseases.展开更多
A non-destructive, safe and practical strategy to produce high quality graphene in high yield is urgently required, since this would pave the way for a wide range of applications of graphene in the future. Here we pre...A non-destructive, safe and practical strategy to produce high quality graphene in high yield is urgently required, since this would pave the way for a wide range of applications of graphene in the future. Here we present a pH-responsive water-dispersible method for the exfoliation and functionalization of graphene by using lysozyme. The pH-responsive dispersion of graphene may be useful for the reversible assembly of multicomponent/multifunctional nanohybrid materials and nanoscale electronic devices. More importantly, composites can be easily constructed through the interactions between disulphide groups in lysozyme and gold nanoparticles （AuNPs）. The resulting graphene-AuNPs composites show excellent catalytic activity towards reduction of o-nitroaniline by NaBH4. Since lysozyme is low cost and has antibacterial properties, and has been widely used in food preservation, medicine and the pharmaceutical industry, our approach may open a new scalable route for the manufacture of high-quality, nondestructive graphene for practical applications.展开更多
文摘The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were char-acterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of glucose at the MoOx/AuNPs composite film was inves-tigated and analyzed in detail. It was shown that the MoOx/AuNPs composite was of strong electrocatalytic activity towards oxidation of glucose as well as other saccharides, so that an attempt was made for direct voltammetric determination of glucose. Then the positive scan polarization reverse catalytic voltammetry was proposed for the first time. Based on this method, the pure oxidation current was extracted by subtraction of the blank current in the reverse scan. The current sensitivity was enhanced tremendously and the signal to noise ra-tio was improved adequately. The electrocatalytic oxidation of glucose at the MoOx/AuNPs modified electrode was performed in alkaline medium, a wide linear range from 0.01 mmol/L to 4.0 mmol/L of glucose, a higher current sensitivity of 2.35 mA/（mmol/L·cm2）, and a lower limit of detection of 9.01 μmol/L （at signal/noise=3） were achieved. In addition, the electrocatalytic oxidation of other saccharides such as lactose, fructose and sucrose was also evaluated.
文摘Here we developed a saccharic colorimetric method based on the combination of chemoselective ligation and enzyme-specific catalysis using aminooxy/ hydrazine-functionalized gold nanoparticles （AO/AuNPs or H/AuNPs）. In the detection of galactose （Gal）, galactohexodialdose （GHDA）, the galactose oxidase （GalOx）-catalyzed product, has an aldehyde group, which allows it to chemoselectively react with an aminooxy or hydrazine group at the outer layer of AO/AuNPs or H/AuNPs by oxime/hydrazone click chemistry to form oxime or hydrozone. Consequent134 through the specific recognition of 1,4-phenylenediboronic acid （PDBA） on cis-diols, GHDA, which contains two pairs of hydroxyls in the cis form, can bind not only with AO/AuNPs or H/AuNPs, but also with PDBA to form boronate diester, thereby triggering the aggregation of AuNPs and causing the corresponding color change. As GalOx catalyzed specific substrates, the amount of Gal correlated with the production of GHDA and the extent of AuNPs aggregation, thus allowing a simple and easily operatable colorimetric method for Gal detection to be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 617 nm to that at 536 nm vary linearly with the logarithmic values of Gal concentrations within a wide range of 500 nM to 5 mM. Moreover, this colorimetric method shows anti-interference capability and high sensitivity with a detection limit of 21 nM. Thus, a universal platform for accurate and specific colorimetric analysis can be established through the integration of chemoselective ligation with enzyme specific catalysis.
文摘The interaction of nanoparticles with proteins is extremely complex, important for understanding the biological properties of nanomaterials, but is very poorly understood. We have employed a combinatorial library of surface modified gold nanoparticles to interrogate the relationships between the nanoparticle surface chemistry and the specific and nonspecific binding to a common, important, and representative enzyme, acetylcholinesterase （ACHE）. We also used Bayesian neural networks to generate robust quantitative structure-property relationship （QSPR） models relating the nanoparticle surface to the AChE binding that also provided significant understanding into the molecular basis for these interactions. The results illustrate the insights that result from a synergistic blending of experimental combinatorial synthesis and biological testing of nanoparticles with quantitative computational methods and molecular modeling.
文摘A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a-D-glucopyranoside （pAPG）, which may induce aggregation of pAPG-functionalized gold nano- particles （AuNPs） to achieve color change of the test solution. Because pAPG is the substrate of α-glucosidase, the aggregation of AuNPs will be influenced by α-glucosidase since there is no coordination reactivity between PDBA and 4-aminobenzene, the hydrolyzed product of pAPG catalyzed by the enzyme. Therefore, a simple and easily-operated colorimetric method for the assay of a-glucosidase activity can be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 650 nm to that at 520 nm vary linearly with the α-glucosidase activity within a range from 0.05 to 1.1 U/mL with a lowest detection limit of 0.004 U/mL. Moreover, using the proposed method, the inhibition effect of gallic acid and quercetin on a-glucosidase activity can be tested with IC50 values of 1.16 mM and 1.82 μM, respectively. Thus, the method has a great potential not only for the detection of a-glucosidase activity, but also for the screening of its inhibitors.
文摘Platinum nanoparticles （NPs） are reported to mimic various anfioxidant enzymes and thus may produce a positive biological effect by reducing reactive oxygen species （ROS） levels. In this manuscript, we report Pt NPs as an enzyme mimic of ferroxidase by depositing platinum nanodots on gold nanorods （Au@Pt NDRs）. Au@Pt NDRs show pH-dependent ferroxidase-like activity and have higher activity at neutral pH values. Cytotoxicity results with human cell lines （lung adenocarcinoma A549 and normal bronchial epithelial cell line HBE） show that Au@Pt NDRs are taken up into cells via endocytosis and translocate into the endosome/lysosome. Au@Pt NDRs have good biocompatibility at NDR particle concentrations lower than 0.15 nM. However, in the presence of H202, lysosome- located NDRs exhibit peroxidase-like activity and therefore increase cytotoxicity. In the presence of FeE＋, the ferroxidase-like activity of the NDRs protects cells from oxidative stress by consuming H202. Thorough consideration should be given to this behavior when employinK Au@Pt NDRs in biological svstems.
基金supported by the National Major Scientific Instruments and Equipments Development Project(ZDYZ2015-2)the Key Research Program of the Chinese Academy of Sciences(QYZDJSSW-SLH025)the National Natural Science Foundation of China(51902313)。
文摘Pancreatic cancer is a devastating malignant disease with 5-year survival rate less than 8%.The impenetrable desmoplastic stroma of pancreatic tissue and serious side-effects of existing drugs hinder the effective treatment for pancreatic carcinoma.Thus,it is imperative to exploit much more safe and efficient methods to prolong the survival of pancreatic cancer patients.In this study,we explored a superior anti-pancreatic cancer strategy based on gadofullerene nanoparticles(GFNPs)using an orthotopic human pancreatic carcinoma(PANC-1)tumor model.It was demonstrated that GFNPs could efficiently suppress orthotopic pancreatic cancer in a dose manner,and significantly extend the survival rate of tumor-bearing mice.Of note,the proteomic profiling of tumor tissues revealed that GFNPs ameliorated the coagulation cascade dysfunction and downregulated the thrombin expression in pancreatic tumor tissues.The regulation of abnormal thrombin by GFNPs was validated in vitro and in vivo.More importantly,GFNPs suppressed orthotopic pancreatic cancer with negligible adverse effects,superior to the widely recognized clinical antipancreatic cancer drug,gemcitabine.Together,this study provides a promising therapeutic for intractable pancreatic cancer as well as a potential to alleviate the cancer-associated thromboembolic diseases.
基金Acknowledgements Financial support was provided by the National Basic Research Program （973 Program） of China （Nos. 2011CB936004 and 2012CB720602）, and theNational Natural Science Foundation of China （NSFC）, Nos. （21210002 and 91213302）.
文摘A non-destructive, safe and practical strategy to produce high quality graphene in high yield is urgently required, since this would pave the way for a wide range of applications of graphene in the future. Here we present a pH-responsive water-dispersible method for the exfoliation and functionalization of graphene by using lysozyme. The pH-responsive dispersion of graphene may be useful for the reversible assembly of multicomponent/multifunctional nanohybrid materials and nanoscale electronic devices. More importantly, composites can be easily constructed through the interactions between disulphide groups in lysozyme and gold nanoparticles （AuNPs）. The resulting graphene-AuNPs composites show excellent catalytic activity towards reduction of o-nitroaniline by NaBH4. Since lysozyme is low cost and has antibacterial properties, and has been widely used in food preservation, medicine and the pharmaceutical industry, our approach may open a new scalable route for the manufacture of high-quality, nondestructive graphene for practical applications.
