Integrated bio-affinity nano-platform into a microfluidic immunosensor based on monoclonal bispecific trifunctional antibodies for the electrochemical determination of epithelial cancer biomarker

KARINA BRAVO; FRANCISCO G. ORTEGA; GERMÁN A. MESSINA; MARÍA I. SANZ FERRAMOLA; MARTÍN A. FERNÁNDEZ-BALDO; JULIO RABA

CLINICA CHIMICA ACTA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 464 p. 64 - 71

0009-8981

Background: The epithelial cell adhesion molecule (EpCAM) is a biomarker that is highly overexpressed on thesurface of epithelial carcinoma cells. In this study, silver nanoparticles covered with polyvinyl alcohol (AgNPs-PVA) were synthesized, characterized and used in a microfluidic immunosensor based on the use of anti-EpCAM recombinant antibodies as a trapping agent.Methods: The concentration of trapped EpCAM is then electrochemically quantified by HRP-conjugated anti-EpCAM-antibody. HRP reacted with its enzymatic substrate in a redox process which resulted in the appearanceof a currentwhose magnitude (at a working voltage as lowas−0.10 V) is directly proportional to the concentrationof EpCAM.Results: Under optimized conditions, the detection limits for the microfluidic immunosensor and a commercialELISA were 0.8 and 13.9 pg/L, respectively. The within-assay and between-assay coefficients of variation arebelow 6.5% for the proposed method. The immunosensor was validated by analyzing patient samples, and agood correlation with a commercial ELISA was obtained.Conclusions: The good analytical performance is attributed to the efficient immobilization of the anti-EpCAM recombinantantibodies on the AgNPs-PVA, and its high specificity for EpCAM. This microfluidic immunosensor isintended for use in diagnosis and prognosis of epithelial cancer, to monitor the disease, and to assess therapeuticefficacy.