A label-free fluorescent aptasensor for specific and ultrasensitive monitoring ochratoxin A（OTA） was developed using the specific aptamer of OTA（OSA） as recognition dement, an aggregation-induced emission（AIE） m...A label-free fluorescent aptasensor for specific and ultrasensitive monitoring ochratoxin A（OTA） was developed using the specific aptamer of OTA（OSA） as recognition dement, an aggregation-induced emission（AIE） molecule（a 9,10-distyrylanthracene with two ammonium groups, DSAI） as a fluorescent probe, and graphene oxide（GO） as a quencher. In the absence of OTA, the AIE probe DSAI and OSA complex（DSAI/OSA） is adsorbed on the GO surface, and the fluorescence of DSAI will be quenched efficiently via the fluorescence resonance energy transfer（FRET） from DSAI to GO. Upon the OTA addition, a more stable complex（OSA-OTA） is formed and released from GO. Meanwhile, DSAI and OSA-OTA can form a new complex（DSAI/OSA-OTA）, then the fluorescent signal of DSAI recovers gradually. Therefore, by introducing GO and DSAI, the fluorescence signal of DSAI can be easily turned from ＂off＂ to ＂on＂ after the addition of OTA, and the ultrasensitive detection of OTA by monitoring the change of the fluorescence signal of DSAI can be readily realized. The detection limit of the assay can reach 0.324 nmol/L with a linear detection range of 10-200 nmol/L. And the aptasensor exhibits high selectivity for OTA against other analogues. Moreover, it has been successfully applied for the detection of OTA in red wine samples.展开更多
Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluor...Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluorescence of terbium ions(Tb^(3+))via binding with single-strand DNA.Mercury ion,Hg^(2+)induced thymine(T)-rich DNA strand to form a double-strand structure(T-Hg^(2+)-T),thus leading to fluorescence reduction.Based on the principle,Hg^(2+)can be quantified based on the fluorescence of Tb^(3+),the limit of detection was 0.0689μmol/L and the linear range was 0.1-6.0μmol/L.Due to the specificity of T-Hg^(2+)-T artificial base pair,the assay could distinguish Hg^(2+)from other metal ions.The recovery rate was ranged in 98.71%-101.34%for detecting mercury pollution in three food samples.The assay is low-cost,separation-free and mix-to-read,thus was a competitive tool for detection of mercury pollution to ensure food safety.展开更多
设计合成了一种长臂发夹型核酸探针,结合核酸外切酶Ⅲ水解反应建立了一种免标记荧光信号放大高灵敏检测DNA的新方法。当不存在靶DNA时, SYBR Green Ⅰ荧光染料能够嵌入发夹型探针的茎部而发出很强的荧光,而当存在靶DNA并与发夹型探针杂...设计合成了一种长臂发夹型核酸探针,结合核酸外切酶Ⅲ水解反应建立了一种免标记荧光信号放大高灵敏检测DNA的新方法。当不存在靶DNA时, SYBR Green Ⅰ荧光染料能够嵌入发夹型探针的茎部而发出很强的荧光,而当存在靶DNA并与发夹型探针杂交后,核酸外切酶Ⅲ从杂交产物的3’端开始水解发夹型探针,释放出靶DNA,并触发下一个酶水解反应,同时SYBR Green Ⅰ染料也随发夹型探针水解而释放,导致荧光信号降低,从而实现了对DNA的免标记荧光信号放大高灵敏检测。该方法的检出限低至320 fmol/L,比传统双标的分子信标的方法降低了4~5个数量级,且该方法还具有免标记、简单、快速的特点。展开更多
We demonstrate the feasibility of simultancous multi-probe detection for an optcal-resolution photoacoustic microscopy(OR-PAM)system.OR-P AM has elicited the attention of biomedical imaging researchers because of its ...We demonstrate the feasibility of simultancous multi-probe detection for an optcal-resolution photoacoustic microscopy(OR-PAM)system.OR-P AM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth.OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules.However,given the inadequate absoption of some biomolcules,detection sensitivity at the same incident intensity requires improvement.In this study,a modulated continuous wave with power density less than 3mW/cm^(2)(1/4 of the ANSI safety limit)excited the weak photoacoustic(PA)signals of biological cells.A microcavity traneducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid;air pressure variation is inversely proportional to cavity volume at the same temperature increase.Considering that a PA wave expands in various directions,detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio.Therefore,we employ four detectors to acquire tiny PA signals simul-taneously.Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.展开更多
[目的]利用PCR法(链式聚合酶反应)制备17号染色体的绿色荧光计数探针。[方法]首先通过对人类基因组17号染色体着丝粒序列分析,找出其特异性的重复序列,设计引物,通过PCR法制备绿色荧光探针,然后利用荧光原位杂交(Fluorescence in situ h...[目的]利用PCR法(链式聚合酶反应)制备17号染色体的绿色荧光计数探针。[方法]首先通过对人类基因组17号染色体着丝粒序列分析,找出其特异性的重复序列,设计引物,通过PCR法制备绿色荧光探针,然后利用荧光原位杂交(Fluorescence in situ hybridization,FISH)实验检验所制备17号染色体计数探针质量。[结果]FISH实验结果显示,利用PCR法制备的计数探针荧光信号清晰可辨。[结论]PCR法可良好地应用于17号染色体计数探针(Chromosome 17 enumeration probe,Cep17)的制备,制备的探针可用于相关疾病的检测。展开更多
In the present work,we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb2?.Pyrene with one positive charge was used as the fluorescent probe,and thrombin aptamer(TBA),whic...In the present work,we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb2?.Pyrene with one positive charge was used as the fluorescent probe,and thrombin aptamer(TBA),which was a G-rich oligonucleotide,was employed to form G-quadruplex with lead(II).When TBA and Pb2?were mixed with lead(II)in an aqueous solution,it was folded into a stable G-quadruplex.Subsequently,a single-stranded nucleic acid-specific nuclease S1 was added.The G-quadruplex stabilized by Pb2?lead(II)had markedly a significant resistant ability to nuclease S1 digestion.However,in the absence of Pb2?lead(II),no quadruplex or less stable quadruplex was formed and TBA was digested by nuclease S1 in 3 min under the optimized experimental conditions.Finally,pyrene probe was mixed with oligonucleotide in Pb2?lead(II).Electrostatic interactions between oligonucleotide(a polyanion)and the probe induced the aggregation of the probe,which in turn produced strong emission of the strong pyrene excimer emission.The intensity of the induced excimer emission was directly proportional to the amount of Pb2?added.Our approach shows good selectivity and sensitivity for the detection of Pb2?with a limit of detection limit as low as 800 nmol/L.展开更多
文摘A label-free fluorescent aptasensor for specific and ultrasensitive monitoring ochratoxin A（OTA） was developed using the specific aptamer of OTA（OSA） as recognition dement, an aggregation-induced emission（AIE） molecule（a 9,10-distyrylanthracene with two ammonium groups, DSAI） as a fluorescent probe, and graphene oxide（GO） as a quencher. In the absence of OTA, the AIE probe DSAI and OSA complex（DSAI/OSA） is adsorbed on the GO surface, and the fluorescence of DSAI will be quenched efficiently via the fluorescence resonance energy transfer（FRET） from DSAI to GO. Upon the OTA addition, a more stable complex（OSA-OTA） is formed and released from GO. Meanwhile, DSAI and OSA-OTA can form a new complex（DSAI/OSA-OTA）, then the fluorescent signal of DSAI recovers gradually. Therefore, by introducing GO and DSAI, the fluorescence signal of DSAI can be easily turned from ＂off＂ to ＂on＂ after the addition of OTA, and the ultrasensitive detection of OTA by monitoring the change of the fluorescence signal of DSAI can be readily realized. The detection limit of the assay can reach 0.324 nmol/L with a linear detection range of 10-200 nmol/L. And the aptasensor exhibits high selectivity for OTA against other analogues. Moreover, it has been successfully applied for the detection of OTA in red wine samples.
基金financially supported by National Natural Science Foundation of China(22074100)the Young Elite Scientist Sponsorship Program by CAST(YESS20200036)+3 种基金the Researchers Supporting Project Number RSP-2021/138King Saud University,Riyadh,Saudi ArabiaTechnological Innovation R&D Project of Chengdu City(2019-YF05-31702266-SN)Sichuan University-Panzhihua City joint Project(2020CDPZH-5)。
文摘Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluorescence of terbium ions(Tb^(3+))via binding with single-strand DNA.Mercury ion,Hg^(2+)induced thymine(T)-rich DNA strand to form a double-strand structure(T-Hg^(2+)-T),thus leading to fluorescence reduction.Based on the principle,Hg^(2+)can be quantified based on the fluorescence of Tb^(3+),the limit of detection was 0.0689μmol/L and the linear range was 0.1-6.0μmol/L.Due to the specificity of T-Hg^(2+)-T artificial base pair,the assay could distinguish Hg^(2+)from other metal ions.The recovery rate was ranged in 98.71%-101.34%for detecting mercury pollution in three food samples.The assay is low-cost,separation-free and mix-to-read,thus was a competitive tool for detection of mercury pollution to ensure food safety.
文摘设计合成了一种长臂发夹型核酸探针,结合核酸外切酶Ⅲ水解反应建立了一种免标记荧光信号放大高灵敏检测DNA的新方法。当不存在靶DNA时, SYBR Green Ⅰ荧光染料能够嵌入发夹型探针的茎部而发出很强的荧光,而当存在靶DNA并与发夹型探针杂交后,核酸外切酶Ⅲ从杂交产物的3’端开始水解发夹型探针,释放出靶DNA,并触发下一个酶水解反应,同时SYBR Green Ⅰ染料也随发夹型探针水解而释放,导致荧光信号降低,从而实现了对DNA的免标记荧光信号放大高灵敏检测。该方法的检出限低至320 fmol/L,比传统双标的分子信标的方法降低了4~5个数量级,且该方法还具有免标记、简单、快速的特点。
基金supported by the National Natural Science Foundation of China(Grant No.61178086)Science and Technology Program of Guangzhou,China(Grant No.2012J4300138)Foundation for Distinguished Young Talents in South China Normal University,China.(Grant No.2012KJ010).
文摘We demonstrate the feasibility of simultancous multi-probe detection for an optcal-resolution photoacoustic microscopy(OR-PAM)system.OR-P AM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth.OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules.However,given the inadequate absoption of some biomolcules,detection sensitivity at the same incident intensity requires improvement.In this study,a modulated continuous wave with power density less than 3mW/cm^(2)(1/4 of the ANSI safety limit)excited the weak photoacoustic(PA)signals of biological cells.A microcavity traneducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid;air pressure variation is inversely proportional to cavity volume at the same temperature increase.Considering that a PA wave expands in various directions,detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio.Therefore,we employ four detectors to acquire tiny PA signals simul-taneously.Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.
基金supported by the National Natural Science Foundation of China(50905071)National Science & Technology Pillar Programme(2009156)
文摘In the present work,we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb2?.Pyrene with one positive charge was used as the fluorescent probe,and thrombin aptamer(TBA),which was a G-rich oligonucleotide,was employed to form G-quadruplex with lead(II).When TBA and Pb2?were mixed with lead(II)in an aqueous solution,it was folded into a stable G-quadruplex.Subsequently,a single-stranded nucleic acid-specific nuclease S1 was added.The G-quadruplex stabilized by Pb2?lead(II)had markedly a significant resistant ability to nuclease S1 digestion.However,in the absence of Pb2?lead(II),no quadruplex or less stable quadruplex was formed and TBA was digested by nuclease S1 in 3 min under the optimized experimental conditions.Finally,pyrene probe was mixed with oligonucleotide in Pb2?lead(II).Electrostatic interactions between oligonucleotide(a polyanion)and the probe induced the aggregation of the probe,which in turn produced strong emission of the strong pyrene excimer emission.The intensity of the induced excimer emission was directly proportional to the amount of Pb2?added.Our approach shows good selectivity and sensitivity for the detection of Pb2?with a limit of detection limit as low as 800 nmol/L.
