A microfluidic electrochemiluminescent device for detecting cancer biomarker proteins

Author(s)

Sardesai, Naimish P. ^[1] ; Kadimisetty, Karteek ^[1] ; Faria, Ronaldo ^{[2, 1]} ; Rusling, James F. ^{[3, 1, 4]}

Affiliation

^[1] Univ Connecticut, Dept Chem, Storrs, CT 06269 - USA

^[2] Univ Fed Sao Carlos, Dept Quim, BR-13560 Sao Carlos, SP - Brazil

^[3] Univ Connecticut, Inst Mat Sci, Storrs, CT 06269 - USA

^[4] Univ Connecticut, Ctr Hlth, Dept Cell Biol, Farmington, CT 06032 - USA

• Document type: Journal article
• Source: ANALYTICAL AND BIOANALYTICAL CHEMISTRY; v. 405, n. 11, p. 3831-3838, APR 2013.
• Web of Science Citations: 63

Abstract

We describe an electrochemiluminescence (ECL) immunoarray incorporated into a prototype microfluidic device for highly sensitive protein detection and apply this system to accurate, sensitive measurements of prostate-specific antigen (PSA) and interleukin-6 (IL-6) in serum. The microfluidic system employed three molded polydime-thylsiloxane (PDMS) channels on a conductive pyrolytic graphite chip (2.5x2.5 cm) inserted into a machined chamber and interfaced with a pump, switching valve, and sample injector. Each of the three PDMS channels encompasses three 3 mu L analytical wells. Capture-antibody-decorated single-wall carbon nanotube forests are fabricated in the bottom of the wells. The antigen is captured by these antibodies on the well bottoms. Then, a RuBPY-silica-secondary antibody (Ab(2)) label is injected to bind to antigen on the array, followed by injection of sacrificial reductant tripropylamine (TPrA) to produce ECL. For detection, the chip is placed into an open-top ECL measuring cell, and the channels are in contact with electrolyte in the chamber. Potential applied at 0.95 V versus Ag/AgCl oxidizes TPrA to produce ECL by redox cycling the RuBPY species in the particles, and ECL light is measured by a charge-coupled device camera. This approach achieved ultralow detection limits of 100 fg mL(-1) for PSA (9 zeptomole) and 10 fgmL(-1) (1 zeptomole) for IL-6 in calf serum, a 10-25-fold improvement of a similar non-microfluidic array. PSA and IL-6 in synthetic cancer patient serum samples were detected in 1.1 h and results correlated well with single-protein enzyme-linked immuno-sorbent assays. (AU)

• FAPESP's process: 11/02259-6 - Development of biosensors for determination of protein biomarkers to applied in early detection and monitoring of cancer
• Grantee: Ronaldo Censi Faria
• Support Opportunities: Scholarships abroad - Research