Integrated microfluidic systems with an immunosensor modified with carbon nanotubes for detection of prostate specific antigen (PSA) in human serum samples

NANCY V. PANINI; GERMÁN A. MESSINA; ELOY SALINAS; HÉCTOR FERNÁNDEZ; JULIO RABA

BIOSENSORS & BIOELECTRONICS

ELSEVIER

Año: 2008 vol. 23 p. 1145 - 1151

0956-5663

This paper describes the development of an immunosensor coupled to glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNT) (CNT-GCE) integrated with microfluidic systems for rapid and sensitive quantification of prostate specific antigen (PSA) in human serum samples. Mouse monoclonal (5G6) to PSA antibodies were immobilized on a rotating disk. PSA in the serum sample are allowed to react immunologically with the immobilized anti-tPSA and horseradish peroxidase (HRP) enzyme-labeled second antibodies specific to PSA. HRP, in the presence of hydrogen peroxide (H2O2) catalyzes the oxidation of 4-tert-butylcatechol (4-TBC), whose back electrochemical reduction was detected on CNT-GCE at −0.15V. The electrochemical detection can be done within 1 min and total assay time was 30 min. The calculated detection limits for electrochemical detection and the ELISA procedure are 0.08 and 0.5 _gL−1, respectively and the intra- and inter-assay coefficients of variation were below 4.5%. The electrochemical immunosensor showed higher sensitivity and lower time consumed than the standard spectrophotometric detection ELISA method, which shows potential for detecting PSA in clinical diagnosis.