| Microbial fuel cells,as a new type of pollutant detection sensor,have received widespread attention from scholars at home and abroad.The purpose of this study is to construct MFC biosensors using commercially available and inexpensive electrodes to detect different concentrations of ciprofloxacin and tobramycin.Firstly,we compared the effects of three different carbon felts,carbon cloths and carbon brush anodes on the electricity generation performance of P.aeruginosa based MFCs.Then,we selected a carbon felt electrode with the best electricity generation performance to construct an MFC,based biosensor.The output was monitored by electrical signals,bacterial activity,phenazine concentration,and qualitative and quantitative determination of the biofilm on the anode surface.Secondly,we compared the effects of different concentrations of ciprofloxacin and tobramycin on the growth and biofilm formation of P.aeruginosa by the dilution broth method,crystal violet staining method,and laser confocal method.The main findings are as follows:1.The effect of different anode materials on the electricity generation performance of P.aeruginosa based MFC showed that the maximum output power density of MFC with carbon felt electrode,MFC with carbon cloth electrode and MFC with carbon brush electrode were 188.57±2.1 m W/m~2,88.36±1.1 m W/m~2 and97.09±1.8 mW/m~2,respectively.The internal resistance values Rct of MFCs were2813.24Ω,4322.16Ω,and 4907.74Ω.Carbon felt electrode based MFCs exhibited the smallest internal resistance of MFC and produce the highest output power.We chose carbon felt electrodes to construct MFC based biosensor for the detection of antibiotics.2.The results of dilution broth showed that the growth of P.aeruginosa was promoted when the concentration of ciprofloxacin was 0-1μg/m L,and the concentration of ciprofloxacin was inhibited by the concentration of 2-64μg/mL.The results of ciprofloxacin detection by P.aeruginosa based MFC indicated that the maximum output voltage of MFC was 154.06±1.20 mV when the concentration of ciprofloxacin was 0μg/mL.When the concentrations of ciprofloxacin were 0.5μg/mL and 1μg/mL,the maximum output voltages of MFC were 149.96±2.1 mV and 143.65±1.1 mV,which were 2.6%and 6.7%lower than those of the control group.When the concentrations of ciprofloxacin were 2μg/mL and 5μg/m L,the maximum output voltages of MFC were 120.75±1.7 m V and 100.61±2.2 mV,which were 21.6%and 34.7%lower than those of the control group.When the concentrations of ciprofloxacin were 10μg/mL and 20μg/mL,the maximum electricity generation voltages of MFC were 47.037±1.06 m V and 45.23±0.85 mV,which were 69.5%and 70.8%lower than those of the control group.With a ciprofloxacin concentration of 40μg/m L,MFC produced almost no electricity.As the concentration of ciprofloxacin increased,the maximum output voltage of the MFC gradually decreased.3.The results of the dilution broth method showed that the growth of P.aeruginosa was promoted when the concentration of tobramycin is 0-0.5μg/mL,and the growth of P.aeruginosa was inhibited when the concentration of tobramycin is1-64μg/mL.The results of tobramycin detection by P.aeruginosa based MFC showed that the maximum output voltage produced by MFC was 154.06±1.20 mV when the concentration of tobramycin was 0μg/mL.When the concentration of tobramycin is 0.5μg/m L,the maximum output voltage of MFC was 144.43±1.1 mV,which was 1.9%lower than that of the control group.When tobramycin concentrations were 1μg/mL and 2μg/mL,the maximum output voltages of MFC were 123.39±1.8 mV and 110.40±1.4 mV,which were 19.9%and 28.2%lower than those of the control group.When the tobramycin concentrations were 5μg/mL and 10μg/mL,the maximum electricity generation voltages of MFCs were 81.10±1.86 mV and 62.02±2.46 mV,respectively,which were 49.4%and 55.2%lower than the control group.With a tobramycin concentration of 20μg/m L,MFC produced almost no electricity.With the increase of tobramycin concentration,the maximum output voltage of MFC gradually decreased.In this paper,a carbon felt material with the best electrochemical performance was selected from three commercial inexpensive electrodes to construct an P.aeruginosa based MFC biosensor,which successfully detected different concentrations of ciprofloxacin and tobramycin.It provides a new method for the detection of antibiotics. |
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