Carbon dots functionalized polyaniline as efficient sensing platform for cancer biomarker detection

Implementing simple and rapid detection of cancer biomarker using biosensors has the potential to contribute greatly to basic biological research and early detection of cancer. Tailoring of biosensor matrix based on conducting polymers has gained significant attention in recent years due to its electroactivity, redox property and biocompatibility. Herein, biomass derived carbon dots (CDs) were anchored on polyaniline (PANI) surface to get biocompatible and fluorescent, carbon dots functionalized polyaniline (CDs@PANI) that enable binding of large amount of prostate cancer biomarker, prostate specific antigen (PSA) antibody on its surface via active functional groups. Immobilization efficiency of CDs@PANI was investigated by electrochemical methods which revealed dense immobilization of biomolecules on CDs@PANI as compared to conventional PANI. A sandwich electrochemical biosensor was constructed using CDs@PANI as immobilization matrix for detection of prostate cancer biomarker PSA. The sensor displayed good sensitivity, specificity, stability, reproducibility, wide linear range (0.01–60 ng/ml) and a low detection limit of 20 pg/ml. The importance of CDs in improving the sensor performance was demonstrated by carrying out detailed electrochemical studies using glucose oxidase as a model biomolecule. Biocompatibility of sensing matrix was assessed by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay for cell viability using WI26 cells. The sensing platform demonstrated herein provides great potential for the detection of different cancer biomarkers and metabolites. [Display omitted] •CDs that anchored on PANI provided carboxylic acid group enriched sensing matrix for PSA detection•CDs enabled binding of large amount of antibodies on sensing matrix.•Immobilization efficiency of CDs@PANI was elaborated by electrochemical impedance spectroscopy and DPV•Electrochemical sandwich immunosensor displayed wide linear range for PSA detection with low detection limit (20 pg/ml)