Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis ...Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction（XRD） and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.展开更多
The safety of nucleic acid staining dyes has long been recognized to be a problem. Extensive efforts have been made to search for alternatives to the most popular but toxic staining dye, ethidium bromide （EtBr）. How...The safety of nucleic acid staining dyes has long been recognized to be a problem. Extensive efforts have been made to search for alternatives to the most popular but toxic staining dye, ethidium bromide （EtBr）. However, so far no staining method that can be guaranteed to be suffidently safe has been developed. In this paper, we report a green staining method of DNA in polyacrylamide gel electrophoresis, where in situ synthesis of DNA-templated fluorescent copper nanoclusters （CuNCs） in the gel is achieved to make the DNA bands visible under UV light. Moreover, a comprehensive study of the performance of this staining method has been conducted and the experimental results show that it has favorable sensitivity, stability, and usability. Meanwhile, in our animal experiments, the two reagents （copper sulfate and ascorbic acid） as well as the synthesized CuNCs have been proven to be non-toxic in contact with skin. In addition, all the reagents employed in this work are readily available and low cost, and the procedure is simple to carry out. Therefore, this novel staining method based on the in situ synthesis DNA-templated fluorescent CuNCs has many potential applications.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
This paper reports a novel method to detect human leukemic lymphoblasts(CCRF-CEM cells).While the aptamer of the cancer cells was employed as the recognition element to target cancer cells,peroxidaseactive DNAzyme was...This paper reports a novel method to detect human leukemic lymphoblasts(CCRF-CEM cells).While the aptamer of the cancer cells was employed as the recognition element to target cancer cells,peroxidaseactive DNAzyme was used as the sensing element to produce catalysis-induced colorimetric signals.The elegant architecture integrating the aptamer and DNAzyme made it feasible to detect cancer cells easily and rapidly by the color change of the substrate for DNAzyme.Experimental results showed that 500 cells can well indicate the cancer,while as control,250,000 Islet Island Beta cells only show tiny signals,suggesting that the method proposed in this paper has considerable sensitivity and selectivity.Furthermore,since it does not require expensive apparatus,or modification or label of DNA chains,the method we present here is also costeffective and conveniently operated,implying potential applications in future cancer diagnosis.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
Pathological bio-mineralization can be induced by diseases such as preeclampsia. Inspired by these naturally occurring bio-mineralization processes, we have designed a process called protein-controlled peptide assembl...Pathological bio-mineralization can be induced by diseases such as preeclampsia. Inspired by these naturally occurring bio-mineralization processes, we have designed a process called protein-controlled peptide assembly tandem peptide- templated bio-mineralization. The technique provides bio-context-associated data on the activity of target proteins, and facilitates the evaluation of protein function in the associated biological microenvironment. It is a bio-mimetic process that leads to the formation of Ag nanoparticle-decorated peptide nanowires, which can offer efficient signal amplification with high sensitivity for biosensing applications. Consequently, high-temperature requirement factor A1 （HtrA1） can be assayed quantitatively in clinical serum samples to offer information for the diagnosis of preeclampsia and the improved treatment of the disease. The results suggest that the process has considerable potential for use in clinical practice.展开更多
Hepatitis C virus (HCV), a positive single-stranded RNA virus, is a major cause of liver disease in humans. Herein we report a novel strategy to inhibit the reproduction and translation of HCV using a short RNA, named...Hepatitis C virus (HCV), a positive single-stranded RNA virus, is a major cause of liver disease in humans. Herein we report a novel strategy to inhibit the reproduction and translation of HCV using a short RNA, named an Additional RNA, to activate the endonuclease activity of Argonaute 2 (Ago2). In the presence of the Additional RNA, the HCV genome RNA has the requisite 12 nucleotides of base-pairing with microRNA-122. This activates the endonuclease activity of Ago2, resulting in cleavage and release of the HCV genome RNA from Ago2 and microRNA-122. The free HCV genome RNA would be susceptible to intracellular degradation, effectively inhibiting its reproduction and translation. This study presents a new method to inhibit HCV that may hold great potential for HCV treatment in the future.展开更多
This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins.Significant achievements in the relevant fields are summarized including the direct electron transfer between ...This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins.Significant achievements in the relevant fields are summarized including the direct electron transfer between proteins and electrodes,the thermodynamic and kinetic properties,catalytic activities and activity regulation of the redox proteins.It has been demonstrated that the electrochemical technique is an effective tool for protein studies,especially for probing into the electron transfer and interfacial behavior of redox proteins.展开更多
Curcumin, a major bioactive compound in turmeric, has a broad spectrum of antioxidant, anticarcinogenic, antimutagenic and anti-inflammatory properties. At the molecular level, curcumin modulates many structurally unr...Curcumin, a major bioactive compound in turmeric, has a broad spectrum of antioxidant, anticarcinogenic, antimutagenic and anti-inflammatory properties. At the molecular level, curcumin modulates many structurally unrelated membrane proteins through several signaling pathways. Curcumin has been suggested to change the properties of cell membranes and affect the membrane-bound proteins indirectly; however, the detailed mechanism has yet to be investigated. In this paper, self-assembled bilayer lipid membranes are artificially constructed on the surface of a gold electrode to miinic biomembranes, and interaction between the supported membranes and curcumin is studied electrochemically. Results show that curcumin interacts with the membranes strongly, in a concentration-dependent manner. At low concentrations, curcumin tends to insert into the outer monolayer only, while at high concentrations, it may also begin to penetrate the inner monolayer. The results obtained in this work may enhance our understanding of the effect of curcumin, and possibly flavonoids, on ceU membranes and membrane proteins.展开更多
In this work, we have prepared Ag nanoclusters （Ag NCs） at gold electrode surface by using thiol-modified oligodeoxynucleotide consisting of eighteen cytosine deoxyribonucleotides （polyC18） as template and NaBH4 a...In this work, we have prepared Ag nanoclusters （Ag NCs） at gold electrode surface by using thiol-modified oligodeoxynucleotide consisting of eighteen cytosine deoxyribonucleotides （polyC18） as template and NaBH4 as reducing agent. Experimental results show that Ag nanoclusters （Ag NCs） can be formed around the template polyC18, while the formation can be characterized with electrochemical method. Further studies reveal that the fab- ricated Ag NCs may display high catalytic activity for the reduction of hydrogen peroxide （H2O2）, which can be further used for the detection of H20〉展开更多
基金the Council of Scientific and Industrial Research, India for the award of senior research fellowship (File. 09/1077/(0001)/ 2012/EMR-1)
文摘Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction（XRD） and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 21235003 and 61001035）, the National Science Fund for Distinguished Young Scholars （Grant No. 20925520）, the Natural Science Foundation of Shanghai （Grant No. 14ZR1416500）, and the Innovation Program of Shanghai Municipal Education Commission （Grant No. 14YZ026）.
文摘The safety of nucleic acid staining dyes has long been recognized to be a problem. Extensive efforts have been made to search for alternatives to the most popular but toxic staining dye, ethidium bromide （EtBr）. However, so far no staining method that can be guaranteed to be suffidently safe has been developed. In this paper, we report a green staining method of DNA in polyacrylamide gel electrophoresis, where in situ synthesis of DNA-templated fluorescent copper nanoclusters （CuNCs） in the gel is achieved to make the DNA bands visible under UV light. Moreover, a comprehensive study of the performance of this staining method has been conducted and the experimental results show that it has favorable sensitivity, stability, and usability. Meanwhile, in our animal experiments, the two reagents （copper sulfate and ascorbic acid） as well as the synthesized CuNCs have been proven to be non-toxic in contact with skin. In addition, all the reagents employed in this work are readily available and low cost, and the procedure is simple to carry out. Therefore, this novel staining method based on the in situ synthesis DNA-templated fluorescent CuNCs has many potential applications.
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.
基金supported by the National Science Fund for Distinguished Young Scholars(Grant No.20925520).
文摘This paper reports a novel method to detect human leukemic lymphoblasts(CCRF-CEM cells).While the aptamer of the cancer cells was employed as the recognition element to target cancer cells,peroxidaseactive DNAzyme was used as the sensing element to produce catalysis-induced colorimetric signals.The elegant architecture integrating the aptamer and DNAzyme made it feasible to detect cancer cells easily and rapidly by the color change of the substrate for DNAzyme.Experimental results showed that 500 cells can well indicate the cancer,while as control,250,000 Islet Island Beta cells only show tiny signals,suggesting that the method proposed in this paper has considerable sensitivity and selectivity.Furthermore,since it does not require expensive apparatus,or modification or label of DNA chains,the method we present here is also costeffective and conveniently operated,implying potential applications in future cancer diagnosis.
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.
基金Acknowledgements This work is supported by the National Natural Science Foundation of China （Nos. 81270710, 81070511, and 21235003）, the Key Clinical Specialist Construction Project of China （No. 2013（544）） and the Networking Project of Prepotency Public Service Platform of Jiangsu Province （No. BM2013058）.
文摘Pathological bio-mineralization can be induced by diseases such as preeclampsia. Inspired by these naturally occurring bio-mineralization processes, we have designed a process called protein-controlled peptide assembly tandem peptide- templated bio-mineralization. The technique provides bio-context-associated data on the activity of target proteins, and facilitates the evaluation of protein function in the associated biological microenvironment. It is a bio-mimetic process that leads to the formation of Ag nanoparticle-decorated peptide nanowires, which can offer efficient signal amplification with high sensitivity for biosensing applications. Consequently, high-temperature requirement factor A1 （HtrA1） can be assayed quantitatively in clinical serum samples to offer information for the diagnosis of preeclampsia and the improved treatment of the disease. The results suggest that the process has considerable potential for use in clinical practice.
基金supported by the National Science Fund for Distinguished Young Scholars (20925520)the National Natural Science Foundation of China (21235003)the Leading Academic Discipline Project of Shanghai Municipal Education Commission (J50108)
文摘Hepatitis C virus (HCV), a positive single-stranded RNA virus, is a major cause of liver disease in humans. Herein we report a novel strategy to inhibit the reproduction and translation of HCV using a short RNA, named an Additional RNA, to activate the endonuclease activity of Argonaute 2 (Ago2). In the presence of the Additional RNA, the HCV genome RNA has the requisite 12 nucleotides of base-pairing with microRNA-122. This activates the endonuclease activity of Ago2, resulting in cleavage and release of the HCV genome RNA from Ago2 and microRNA-122. The free HCV genome RNA would be susceptible to intracellular degradation, effectively inhibiting its reproduction and translation. This study presents a new method to inhibit HCV that may hold great potential for HCV treatment in the future.
基金support from the National Natural Science Foundation of China(Grant Nos.90406005&20575028)the Program for New Century Excellent Talents in University,the Chinese Ministry of Education(Grant No.NCET-04-0452)
文摘This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins.Significant achievements in the relevant fields are summarized including the direct electron transfer between proteins and electrodes,the thermodynamic and kinetic properties,catalytic activities and activity regulation of the redox proteins.It has been demonstrated that the electrochemical technique is an effective tool for protein studies,especially for probing into the electron transfer and interfacial behavior of redox proteins.
基金supported by the National Science Fund for Distinguished Young Scholars(Grant No.20925520)the National Natural Science Foundation of China(Grant No.81070511)the Leading Academic Discipline Project of Shanghai Municipal Education Commission(Grant No.J50108)
文摘Curcumin, a major bioactive compound in turmeric, has a broad spectrum of antioxidant, anticarcinogenic, antimutagenic and anti-inflammatory properties. At the molecular level, curcumin modulates many structurally unrelated membrane proteins through several signaling pathways. Curcumin has been suggested to change the properties of cell membranes and affect the membrane-bound proteins indirectly; however, the detailed mechanism has yet to be investigated. In this paper, self-assembled bilayer lipid membranes are artificially constructed on the surface of a gold electrode to miinic biomembranes, and interaction between the supported membranes and curcumin is studied electrochemically. Results show that curcumin interacts with the membranes strongly, in a concentration-dependent manner. At low concentrations, curcumin tends to insert into the outer monolayer only, while at high concentrations, it may also begin to penetrate the inner monolayer. The results obtained in this work may enhance our understanding of the effect of curcumin, and possibly flavonoids, on ceU membranes and membrane proteins.
文摘In this work, we have prepared Ag nanoclusters （Ag NCs） at gold electrode surface by using thiol-modified oligodeoxynucleotide consisting of eighteen cytosine deoxyribonucleotides （polyC18） as template and NaBH4 as reducing agent. Experimental results show that Ag nanoclusters （Ag NCs） can be formed around the template polyC18, while the formation can be characterized with electrochemical method. Further studies reveal that the fab- ricated Ag NCs may display high catalytic activity for the reduction of hydrogen peroxide （H2O2）, which can be further used for the detection of H20〉
