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

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 (r(2) = 0.9986) and -146.2 +/- 2.3 mV/decade (r(2) = 0.9991) slopes over the linearity range 1.5 mu M-1.5 mM with 0.8 and 1.0 mu M 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 x 10(-8) and 1.8 x 10(-7) M over the linear ranges of 5.2x10(-8)-1.0x10(-4) M and 1.4x10(-6)-1.4x10(-3) M, with 0.09 +/- 0.004 and 0.168 +/- 0.009 log omega/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.