Novel electrochemical biosensing platform based on conductive multilayer for sensitive and selective detection of CYFRA 21-1

Abstract

In the present work, an electrochemical biosensor modified with a conductive multilayer composed of gold nanoparticles and amino-substituted-pyrrole polymer (AuNPs/P(PyAmn)) was constructed for label-free detec-tion of cytokeratin 19 fragment 21-1 (CYFRA 21-1), one of the most important lung cancer biomarkers. The electrochemical biosensor was fabricated by electropolymerization of PyAmn on an indium tin oxide (ITO) platform with electrodeposition of AuNPs and binding of an anti-CYFRA 21-1 recognition element on the P (PyAmn)-coated electrode via glutaraldehyde crosslinking. In the present immunosensor, AuNPs deposition provided excellent conductivity and good electron transfer. The electropolymerization of the P(PyAmn) polymer layer ensured a large surface area that increased the amount of anti-CYFRA 21-1 antibodies that could be attached. A specific immunoreaction occurred between anti-CYFRA 21-1 antibody and CYFRA 21-1 antigen when the immunosensor was successively reacted with the target CYFRA 21-1 protein. According to specific immu-noreactions, the resulting biosensor produced an impedimetric signal proportional to the amount of CYFRA 21-1 in the linear detection range of 0.015-90 pg/mL. With optimal fabrication parameters, the detection limit, quantification limit and sensitivity for CYFRA 21-1 were 4.59 pg/mL, 15.31 pg/mL and 0.21 k Omega pg(-1) mL cm(-2), respectively. Meanwhile, this biosensor had good stability and high specificity for CYFRA 21-1 detection, and it was successfully applied to real serum samples. It also had a satisfactory rate of R-2 = 0.9984. The use of a disposable ITO substrate as a basis for this immunosensor allowed the use of simple instrumentation. This study illustrates a new approach to fabricate an ultrasensitive and label-free electrochemical biosensor based on a disposable platform for CYFRA 21-1 analysis in clinical biosensing.