Flexible HIV-1 Biosensor Based on the Au/MoS(2) Nanoparticles/Au Nanolayer on the PET Substrate

Shin, Minkyu; Yoon, Jinho; Yi, Chanyong; Lee, Taek; Choi, Jeong-Woo

The SWV technique was performed to investigate the electrochemical detection performance and selectivity of the fabricated biosensor. To confirm its detection, the gp120 antigen dissolved in PBS solution was immobilized on the prepared Ab/Cys/Au/MoS2/Au nanolayer on the PET substrate for 1 h at room temperature. The detection of the gp120 antigen at a concentration of 0.1 pg/mL to 10 ng/mL was confirmed by SWV. As shown in Figure 5a , the electron transfer reaction between the redox probe and the biosensor surface was blocked by the antigen-antibody binding on the surface of the fabricated biosensor, and the current value was decreased when the concentration of the gp120 antibody was increased. In addition, the linearity of the current value for the gp120 antigen concentration was confirmed through the results obtained from SWV. As shown in Figure 5b , the gp120 antigen ranged from 0.1 pg/mL to 10 ng/mL and showed excellent linearity with 0.973 of the coefficient of determination value (R 2 ). In general, the concentration of gp120 in HIV-infected patients is approximately 200 pg/mL to 2000 pg/mL, therefore the fabricated biosensor showed the possibility for gp120 detection in practice. The mean value and the error bars were plotted with the standard deviation (SD) from four different measurements. The detection limit of an electrochemical biosensor composed of the Au/MoS2/Au nanolayer on the PET substrate for HIV detection was 0.066 pg/mL based on the 3 × (S/m) method, where S is the standard deviation of the blank signal and m is slope of the linear fitting curve, and this value was compared with other electrodes shown in Table 1 . To confirm the detection ability for the gp120 antigen prepared from a real sample, human serum was mixed with the gp120 antigen, and the detection of the gp120 antigen was confirmed by SWV. For real sample analysis, the gp120 with different concentrations from 1 pg/mL to 10 ng/mL was mixed with serum. As shown in Figure 5c , in the case of the gp120 antigen prepared in serum, the current