FOOD SCIENCE ›› 2022, Vol. 43 ›› Issue (16): 351-358.doi: 10.7506/spkx1002-6630-20210621-249

• Safety Detection • Previous Articles    

Detection of Cu2+ Using Methanobactin-coupled Lipase Biosensor with Differential Pulse Voltammetry

WANG Yan, ZHAO Ning, WANG Yue, LI Hongjia, XIN Jiaying, SUN Lirui, GUAN Huanan   

  1. (Key Laboratory of Food Science and Engineering, Harbin University of Commerce, Harbin 150076, China)
  • Online:2022-08-25 Published:2022-08-31

Abstract: In this study, a methanobactin (Mb)-coupled lipase biosensor was constructed based on the fact that Mb can specifically capture Cu2+. Lipase immobilized on gold nanoparticles (Lipase@AuNPs) was successfully prepared and its structure and morphology were characterized by fluorescence, ultraviolet-visible (UV-vis) and Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM). The biosensor could monitor the response of electrical signals during the hydrolysis of triolein by lipase. Cu2+ specifically combined with Mb and was enriched around lipase, which inhibited the catalytic activity of lipase and significantly reduced the current intensity, thus allowing rapid qualitative and ultra-trace reverse quantitative detection of Cu2+. The results showed that the optimal detection conditions, as determined by differential pulse voltammetry (DPV), were as follows: substrate concentration 2 g/100 mL and buffer pH 7.5. The sensor current difference had a good linear relationship with Cu2+ concentration in the range of 1–100 nmol/L. The regression equation was as follows: y = 0.228x + 0.774 8, with a correlation coefficient (R2) of 0.995 0, and the detection limit of this method was 0.03 nmol/L (RSN = 3). Therefore, the new lipase biosensor has high sensitivity, specificity and stability, which lays a research foundation for the detection of trace and ultra-trace heavy metals in foods.

Key words: methanobactin; gold nanoparticles; lipase biosensor; differential pulse voltammetry; trace detection of Cu2+

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