In the present study we carried out the synthesis of β-cyclodextrin （β-CD） functionalized gold nanoparticles （AuNPs） using a microwave assisted heating method in alkaline media. Stable dispersion of β-CD stabil...In the present study we carried out the synthesis of β-cyclodextrin （β-CD） functionalized gold nanoparticles （AuNPs） using a microwave assisted heating method in alkaline media. Stable dispersion of β-CD stabilized AuNPs was obtained at an optimized pH of 10,5. At this pH value the deprotonated secondary hydroxyl group of β-CD shows the highest chelating affinity toward Pb2＋ ions thereby inducing AuNP aggregation. The Pb2＋ induced aggregation in β-CD-AuNP solution is monitored by both colorimetric response and UV-Vis spectroscopy. TEM, DLS and FTIR analyses were carried out to confirm the Pb2＋ ion induced aggregation behaviour of β-CD-AuNPs under alkaline conditions. Furthermore at the experimental pH the response of the β-CD-AuNP system towards Pb2＋ ions is selective when compared with other interfering metal cations.展开更多
Au nanoparticles(AuNPs) were electrodeposited at the highly ordered anatase TiO_2 nanotube array(TiO_2 NA) electrode under sonicating, and the AuNP-TiO_2 NA sensor was characterized by scanning electron microscope(SEM...Au nanoparticles(AuNPs) were electrodeposited at the highly ordered anatase TiO_2 nanotube array(TiO_2 NA) electrode under sonicating, and the AuNP-TiO_2 NA sensor was characterized by scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD). The photoelectrochemical experiments indicate the AuNP-TiO_2 NA sensor has lower photoelectro-resistance,higher photoelectrocatalytical activity and stability than that of pure TiO_2 NA sensor under the same conditions. The as-prepared sensor can be used for the determination of chemical oxygen demand(COD)in real samples, and the obtained results are comparable well with those of by standard K_2Cr_2O_7 method.The method proposed is simple, fast, cost effective, and environmentally friendly.展开更多
A gold nanoparticle(AuNP)aggregation-induced colorimetric aptasensing method for quantitative detection of sulfadimethoxine(SDM)with a smartphone was developed.AuNPs were complexed with aptamers which protected Au NPs...A gold nanoparticle(AuNP)aggregation-induced colorimetric aptasensing method for quantitative detection of sulfadimethoxine(SDM)with a smartphone was developed.AuNPs were complexed with aptamers which protected Au NPs from aggregating in high-concentration salt solutions.In the presence of SDM,SDM bound with the aptamer on the surface of Au NPs with higher affinity,which competitively desorbed the aptamer from the AuNP surface and resulted in AuNPs aggregation,accompanied with a color change from red to purple-blue.The R,G and B values of images taken by a smartphone camera were analyzed with an app on the smartphone,and were utilized for quantitative analysis of SDM.Under the optimized conditions,the colorimetric aptasensing method using a smartphone showed high sensitivity for SDM,with the limit of detection of 0.023 ppm,lower than the allowed maximum SDM residue limit.This study provides a simple,fast,and easy to read method for on-site quantitative biochemical and cellular analysis.展开更多
Saxitoxin(STX),one of the most toxic paralytic shellfish poisons discovered to date,is listed as a required item of aquatic product safety inspection worldwide.However,conventional detection methods for STX are limite...Saxitoxin(STX),one of the most toxic paralytic shellfish poisons discovered to date,is listed as a required item of aquatic product safety inspection worldwide.However,conventional detection methods for STX are limited by various issues,such as low sensitivity,complicated operations,and ethical considerations.In this study,an aptamer-triplex molecular switch(APT-TMS)and gold nanoparticle(AuNP)nanozyme were combined to develop a label-free colorimetric aptasensor for the rapid and highly sensitive de-tection of STX.An anti-STX aptamer designed with pyrimidine arms and a purine chain was fabricated to form an APT-TMS.Specific binding between the aptamer and STX triggered the opening of the switch,which causes the purine chains to adsorb onto the surface of the AuNPs and enhances the peroxidase-like activity of the AuNP nanozyme toward 3,3’,5,5’-tetramethylbenzidine.Under optimized conditions,the proposed aptasensor showed high sensitivity and selectivity for STX,with a limit of detection of 335.6 pmol L^(−1) and a linear range of 0.59-150 nmol L^(−1).Moreover,good recoveries of 82.70%-92.66%for shellfish and 88.97%-106.5%for seawater were obtained.The analysis could be completed within 1 h.The proposed design also offers a robust strategy to achieve detection of other marine toxin targets by altering the corresponding aptamers.展开更多
文摘In the present study we carried out the synthesis of β-cyclodextrin （β-CD） functionalized gold nanoparticles （AuNPs） using a microwave assisted heating method in alkaline media. Stable dispersion of β-CD stabilized AuNPs was obtained at an optimized pH of 10,5. At this pH value the deprotonated secondary hydroxyl group of β-CD shows the highest chelating affinity toward Pb2＋ ions thereby inducing AuNP aggregation. The Pb2＋ induced aggregation in β-CD-AuNP solution is monitored by both colorimetric response and UV-Vis spectroscopy. TEM, DLS and FTIR analyses were carried out to confirm the Pb2＋ ion induced aggregation behaviour of β-CD-AuNPs under alkaline conditions. Furthermore at the experimental pH the response of the β-CD-AuNP system towards Pb2＋ ions is selective when compared with other interfering metal cations.
基金supported by the National Key Research and Development Program of China (No. 2016YFC1102802)Guangdong Innovative and Entrepreneurial Research Team Program (No. 2013C092)
文摘Au nanoparticles(AuNPs) were electrodeposited at the highly ordered anatase TiO_2 nanotube array(TiO_2 NA) electrode under sonicating, and the AuNP-TiO_2 NA sensor was characterized by scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD). The photoelectrochemical experiments indicate the AuNP-TiO_2 NA sensor has lower photoelectro-resistance,higher photoelectrocatalytical activity and stability than that of pure TiO_2 NA sensor under the same conditions. The as-prepared sensor can be used for the determination of chemical oxygen demand(COD)in real samples, and the obtained results are comparable well with those of by standard K_2Cr_2O_7 method.The method proposed is simple, fast, cost effective, and environmentally friendly.
基金the National Natural Science Foundation of China(Nos.21874098 and 61775157)Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi,Key R&D plan of Shanxi Province(International cooperation)(No.201903D421053)+3 种基金Key R&D Plan of Shanxi Province(high technologies field,No.201903D121158)the U.S.NSF(Nos.IIP2122712 and IIP 2052347)CPRIT(No.RP210165)DOT(No.CARTEEH)。
文摘A gold nanoparticle(AuNP)aggregation-induced colorimetric aptasensing method for quantitative detection of sulfadimethoxine(SDM)with a smartphone was developed.AuNPs were complexed with aptamers which protected Au NPs from aggregating in high-concentration salt solutions.In the presence of SDM,SDM bound with the aptamer on the surface of Au NPs with higher affinity,which competitively desorbed the aptamer from the AuNP surface and resulted in AuNPs aggregation,accompanied with a color change from red to purple-blue.The R,G and B values of images taken by a smartphone camera were analyzed with an app on the smartphone,and were utilized for quantitative analysis of SDM.Under the optimized conditions,the colorimetric aptasensing method using a smartphone showed high sensitivity for SDM,with the limit of detection of 0.023 ppm,lower than the allowed maximum SDM residue limit.This study provides a simple,fast,and easy to read method for on-site quantitative biochemical and cellular analysis.
基金funded by the National Natural Science Foundation of China(No.31801620).
文摘Saxitoxin(STX),one of the most toxic paralytic shellfish poisons discovered to date,is listed as a required item of aquatic product safety inspection worldwide.However,conventional detection methods for STX are limited by various issues,such as low sensitivity,complicated operations,and ethical considerations.In this study,an aptamer-triplex molecular switch(APT-TMS)and gold nanoparticle(AuNP)nanozyme were combined to develop a label-free colorimetric aptasensor for the rapid and highly sensitive de-tection of STX.An anti-STX aptamer designed with pyrimidine arms and a purine chain was fabricated to form an APT-TMS.Specific binding between the aptamer and STX triggered the opening of the switch,which causes the purine chains to adsorb onto the surface of the AuNPs and enhances the peroxidase-like activity of the AuNP nanozyme toward 3,3’,5,5’-tetramethylbenzidine.Under optimized conditions,the proposed aptasensor showed high sensitivity and selectivity for STX,with a limit of detection of 335.6 pmol L^(−1) and a linear range of 0.59-150 nmol L^(−1).Moreover,good recoveries of 82.70%-92.66%for shellfish and 88.97%-106.5%for seawater were obtained.The analysis could be completed within 1 h.The proposed design also offers a robust strategy to achieve detection of other marine toxin targets by altering the corresponding aptamers.
