An electrochemical biosensor was developed based on a steric hindrance hybridization assay to allow the highly sensitive detection of streptavidin. In the steric hindrance hybridization assay, the signaling strand DNA (sig-DNA) was labeled at the 3′ end with CdSe quantum dots (QDs) and at the 5′ end with biotin, and capturing strand DNA (the complementary strand of sig-DNA) was labeled at the 5′ end with thiol. The steric hindrance effect generated by streptavidin which was bound with the signaling DNA strand. The streptavidin limited the ability of the sig-DNA to hybridize with the cap-DNA, which were linked on the surface of a gold electrode. Therefore, the concentration of streptavidin was detected indirectly based on the concentration of CdSe QDs on the electrode surface. The concentration of CdSe QDs on the electrode surface was detected by differential pulse anodic stripping voltammetry. Under optimal conditions, the streptavidin detection range using the as-prepared biosensor was 1.96 pg/mL to 1.96 µg/mL and the detection limit was 0.65 pg/mL. The experimental results showed that the electrochemical biosensor could detect streptavidin rapidly and accurately.

基于空间位阻杂交测定法开发了一种电化学生物传感器，以允许对链霉亲和素进行高度灵敏的检测。在空间位阻杂交试验中，信号链DNA（sig-DNA）在3'端用CdSe量子点（QDs）标记，在5'端用生物素标记，并捕获链DNA（sig-DNA的互补链） DNA）在5'端用硫醇标记。由链霉亲和素产生的位阻效应与信号DNA链结合。链霉亲和素限制了sig-DNA与连接在金电极表面的cap-DNA杂交的能力。因此，基于电极表面上CdSe QDs的浓度间接检测了链霉亲和素的浓度。通过差分脉冲阳极溶出伏安法检测电极表面CdSe QDs的浓度。在最佳条件下，使用准备好的生物传感器检测链霉亲和素的范围为1.96 pg / mL至1.96 µg / mL，检出限为0.65 pg / mL。实验结果表明，该电化学生物传感器能够快速，准确地检测链霉亲和素。