A Label-Free Electrochemical Biosensor for Homocysteine Detection Using Molecularly Imprinted Polymer and Nanocomposite-Modified Electrodes

Abstract

An essential biomarker for the early detection of cardiovascular diseases is serum homocysteine (Hcy). In this study, a molecularly imprinted polymer (MIP) and nanocomposite were used to create a label-free electrochemical biosensor for reliable Hcy detection. A novel Hcy-specific MIP (Hcy-MIP) was synthesized using methacrylic acid (MAA) in the presence of trimethylolpropane trimethacrylate (TRIM). The Hcy-MIP biosensor was fabricated by overlaying the mixture of Hcy-MIP and the carbon nanotube/chitosan/ionic liquid compound (CNT/CS/IL) nanocomposite on the surface of a screen-printed carbon electrode (SPCE). It showed high sensitivity, with a linear response of 5.0 to 150 µM (R2 of 0.9753) and with a limit of detection (LOD) at 1.2 µM. It demonstrated low cross-reactivity with ascorbic acid, cysteine, and methionine. Recoveries of 91.10–95.83% were achieved when the Hcy-MIP biosensor was used for Hcy at 50–150 µM concentrations. The repeatability and reproducibility of the biosensor at the Hcy concentrations of 5.0 and 150 µM were very good, with coefficients of variation at 2.27–3.50% and 3.42–4.22%, respectively. This novel biosensor offers a new and effective method for Hcy assay compared with the chemiluminescent microparticle immunoassay at the correlation coefficient (R2) of 0.9946.

Recent Advances in Electrochemical Sensors for Sulfur-Containing Antioxidants

“…The detection limits achieved the nM-pM level [ 134 , 138 , 139 , 146 , 150 , 152 , 154 , 156 , 157 , 158 , 160 , 161 ]. The reason for this is the synergetic effects of different modifiers, in particular: High surface area and conductivity due to the carbon-based nanomaterials including 3D porous structures (hierarchical amorphous carbon network [ 128 ], MOF [ 156 ], MXene [ 158 ]); Conductivity and adsorption affinity due to the metal NPs and ions [ 126 , 127 , 128 , 129 , 131 , 134 , 136 , 140 , 143 , 153 , 158 , 161 , 166 ] as well as electrochemical mediator properties; High surface area and electrochemical mediator function due to the metal oxide NPs and their composites [ 124 , 125 , 136 , 138 , 141 , 151 , 157 , 165 ]; Anti-fouling effects due to the presence of polymers like Nafion [ 129 ], chitosan [ 148 , 163 …”

“…Anti-fouling effects due to the presence of polymers like Nafion [ 129 ], chitosan [ 148 , 163 ] or polyethylene glycol [ 163 ];…”

“…High affinity of polymers including molecularly imprinted ones to the sulfur-containing antioxidants [ 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 156 , 157 ].…”

“…One of the approaches to provide specific recognition of the analytes is fabrication of molecularly imprinted polymers (MIP). MIP-based sensors allow obtaining of a highly sensitive response to homocysteine [ 148 , 149 ] and l -cysteine [ 152 ]. A label-free electrochemical sensor for reliable homocysteine detection has been fabricated from screen-printed carbon electrode covered with carbon nanotube/chitosan/ionic liquid nanocomposite with MIP synthetized from the methacrylic acid in the presence of trimethylolpropane trimethacrylate as a cross-linking agent and 2,2′-azobis(2-methylpropio nitrile) as a radical-induced polymerization initiator ( Figure 16 ).…”

“…( a ) The screen-printed carbon electrode (SPCE) was modified with the mixture of Hcy-MIP and carbon nanotube/chitosan/ionic liquid (CNT/CS/IL) nanocomposite; ( b ) Hcy detection by measuring the differential pulse voltammetric response using [Fe(CN) 6 ] 3−/4− as an electroactive probe molecule. Reprinted from [ 148 ]; published under Creative Commons CC BY license.…”