Rapid and specific detection of LDL based on light addressable potentiometric sensor decorated with reduced graphene oxide-polyaniline-hemin nanocomposites

Atherosclerotic Cardiovascular Disease (ASCVD) is one of the major fatal diseases for humans and the fatality rate is increasing rapidly. Low density lipoprotein (LDL) is a serum key marker in the diagnosis of ASCVD because LDL level is associated with the prevalence of ASCVD. Herein, a light addressable potentiometric sensor (LAPS) was constructed for rapid detection of LDL using reduced graphene oxide-polyaniline-hemin nanocomposites (RGO-PANI-HNCs) and low density lipoprotein aptamer (LDLapt) as sensitive membrane of LAPS. Under the effect of bias voltage, the specific binding between LDL and LDLapt, and forming the LDL-LDLapt complex will cause the voltage change on the sensitive membrane surface of the LAPS system, which will cause the change of original current–voltage (I-V) balance in the circuit, resulting in the shift of I-V curve. The correlation between the potential shift of LAPS and LDL concentration was linear from 1.0 to 100.0 μg/mL under optimal conditions. The sensitivity is 4.7671 mV/μg/mL, and the detection limit is 0.79 μg/mL. Also, the LDL biosensor showed satisfactory specificity, selectivity, reproducibility, and showed a good precision in real human serum samples, which provides a simple and effective way for the early diagnosis of ASCVD.