Screen-printed electrochemical sensors for label-free potentiometric and impedimetric detection of human serum albumin

Abstract

Herein, two electrochemical methods based on potentiometric and impedimetric transductions were presented for albumin targeting, employing screen-printed platforms (SPEs) to make easy and cost-effective sensors with good detection merits. The SPEs incorporated ion-to-electron multi-walled carbon nanotubes (MWCNTs) transducer. Sensors were constructed using either tridodecyl methyl-ammonium chloride (TDMACl) (sensor I) or aliquate 336S (sensor II) in plasticized polymeric matrices of carboxylated poly (vinyl chloride) (PVC-COOH). Analytical performances of the sensors were evaluated using the above-mentioned electrochemical techniques. For potentiometric assay, constructed sensors responded to albumin with −81.7 ± 1.7 (r2 = 0.9986) and −146.2 ± 2.3 mV/decade (r2 = 0.9991) slopes over the linearity range 1.5 μM–1.5 mM with 0.8 and 1.0 μM detection limits for respective TDMAC- and aliquate-based sensors. Interference study showed apparent selectivity for both sensors. Impedimetric assays were performed at pH = 7.5 in 10 mM PBS buffer solution with a 0.02 M [Fe(CN)6]−3/−4 redox-active electrolyte. Sensors achieved detection limits of 4.3 × 10−8 and 1.8 × 10−7 M over the linear ranges of 5.2×10−8–1.0×10−4 M and 1.4×10−6–1.4×10−3 M, with 0.09 ± 0.004 and 0.168 ± 0.009 log Ω/decade slopes for sensors based on TDMAC and aliquate, respectively. These sensors are characterized with simple construction, high sensitivity and selectivity, fast response time, single-use, and cost-effectiveness. The methods were successfully applied to albumin assessment in different biological fluids.