Facile and Compact Electrochemical Paper-Based Analytical Device for Point-of-Care Diagnostic of Dual Carcinogen Oxidative Stress Biomarkers through a Molecularly Imprinted Polymer Coated on Graphene Quantum-Dot Capped Gold
Maliwan Amatatongchai, Nongyao Nontawong, Pattanun Ngaosri, Suticha Chunta, Surasak Wanram, Purim Jarujamrus, Duangjai Nacapricha, Peter A. Lieberzeit
Abstract
Nanoscale imprinting significantly increases the specific surface area and recognition capabilities of a molecularly imprinted polymer by improving accessibility to analytes, binding kinetics, and template removal. Herein, we present a novel synthetic route for a dual molecularly imprinted polymer (dual-MIP) of the carcinogen oxidative stress biomarkers 3-nitrotyrosine (3-NT) and 4-nitroquinolin-N-oxide (4-NQO) as coatings on graphene quantum-dot capped gold nanoparticles (GQDs-AuNPs). The dual-MIP was successfully coated on the GQDs-AuNPs core via a (3-mercaptopropyl) trimethoxysilane (MPTMS) linkage and copolymerization with the 3-aminopropyltriethoxysilane (APTMS) functional monomer. In addition, we fabricated a facile and compact three-dimensional electrochemical paper-based analytical device (3D-ePAD) for the simultaneous determination of the dual biomarkers using a GQDs-AuNPs@dual-MIP-modified graphene electrode (GQDs-AuNPs@dual-MIP/SPGE). The developed dual-MIP device provides greatly enhanced electrochemical signal amplification due to the improved electrode-specific surface area, electrocatalytic activity, and the inclusion of large numbers of dual-imprinted sites for 3-NT and 4-NQO detection. Quantitative analysis used square wave voltammetry, with an oxidation current appearing at -0.10 V for 4-NQO and +0.78 V for 3-NT. The dual-MIP sensor revealed excellent linear dynamic ranges of 0.01 to 500 μM for 3-NT and 0.005 to 250 μM for 4-NQO, with detection limits in nanomolar levels for both biomarkers. Furthermore, the dual-MIP sensor for the simultaneous determination of 3-NT and 4-NQO provides high accuracy and precision, with no evidence of interference from urine, serum, or whole blood samples.