Vibrio parahaemolyticus is the leading causal agent of human acute gas- troenteritis. Real-time accurate detection means is the key to prevention and control of its spread. This study provided a novel detection strate...Vibrio parahaemolyticus is the leading causal agent of human acute gas- troenteritis. Real-time accurate detection means is the key to prevention and control of its spread. This study provided a novel detection strategy for realizing rapid and specific determination of V. parahaemolyticus by labeling its monoclonal antibody （Ab） with quantum dots （QDs）. The results showed that the fluorescence of these QDs-Ab bioconjugates was quenched by graphene oxide （GO） to produce a bacteri- um capture probe. And the optimal quenched concentration of GO was 60 ng/ml. When the bacterium capture probe was exposed to the target, green color fluores- cence was turned on by releasing the QDs-Ab due to the antibody antigen combi- nation. The detection limit of V. parahaemolyticus was 104 CFU/ml based on 3 times signal-to-noise ratio. The specificity of the FRET sensor towards V. para- haemolyticus was examined by comparing with controls such as V. splendidus, V. alginolyticus, Edwardsiella tarda and Aeromonas hydrophila with the same condition. The controls couldn＇t cause obvious fluorescence alteration, while the target resulted in significant fluorescence enhancement. This strategy could be further used as a universal method for any bacterial determination by changing the conjugated antibod- ies in early disease diagnosis. Therefore, the sensor has good potential to expand its application to the early diagnosis and determination of bacteria.展开更多
Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted elect...Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted electron transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate electron-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered electron-transport mechanisms will lead to significant advances in MFC engineering.展开更多
基金Supported by Shandong Scientific and Technological Development Program(2014GHY115024)~~
文摘Vibrio parahaemolyticus is the leading causal agent of human acute gas- troenteritis. Real-time accurate detection means is the key to prevention and control of its spread. This study provided a novel detection strategy for realizing rapid and specific determination of V. parahaemolyticus by labeling its monoclonal antibody （Ab） with quantum dots （QDs）. The results showed that the fluorescence of these QDs-Ab bioconjugates was quenched by graphene oxide （GO） to produce a bacteri- um capture probe. And the optimal quenched concentration of GO was 60 ng/ml. When the bacterium capture probe was exposed to the target, green color fluores- cence was turned on by releasing the QDs-Ab due to the antibody antigen combi- nation. The detection limit of V. parahaemolyticus was 104 CFU/ml based on 3 times signal-to-noise ratio. The specificity of the FRET sensor towards V. para- haemolyticus was examined by comparing with controls such as V. splendidus, V. alginolyticus, Edwardsiella tarda and Aeromonas hydrophila with the same condition. The controls couldn＇t cause obvious fluorescence alteration, while the target resulted in significant fluorescence enhancement. This strategy could be further used as a universal method for any bacterial determination by changing the conjugated antibod- ies in early disease diagnosis. Therefore, the sensor has good potential to expand its application to the early diagnosis and determination of bacteria.
基金Supported by the National Natural Science Foundation of China (No.41076047)the Shandong Provincial Natural Science Foundation of China (No. ZR2010DM004)the Chinese Academy of Sciences (No. KZCX2-YW-205-03)
文摘Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted electron transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate electron-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered electron-transport mechanisms will lead to significant advances in MFC engineering.
