Ultra-trace electrochemical impedance determination of bovine serum albumin by a two dimensional silica network citrate-capped gold nanoparticles modified gold electrode

In this work, two dimension silica network/ citrate capped gold nanoparticles/poly (diallydimethylammonium chloride) modified gold electrode (TDSN-CGNP-PDDA-GE) wasprepared for ultrasensitive determination of Bovine Serum Albumin (BSA). Analytical properties of TDSN-CGNP-PDDA-GE were studied by Electrochemical Impedance Spectroscopy (EIS). The detection limit for BSA was found to be 8.38×10-13 mol L-1 and the linear concentrationrange of the proposed sensor was 9.9×10-12-1.6×10-10 mol L-1. Also, TDSN-CGNP-PDDA-GE showed good stability and selectivity and was applied for determination of BSA in bovine serumsample with satisfactory result. One of the major components of blood plasma is albumin. Albumin concentration level isconsidered as vital parameter for the diagnosis of significant problems in biological system [1-3]. In recent years Electrochemical Impedance Spectroscopy (EIS) sensors are widely used to the characterization and determination in bioanalytical field [4]. However, to the best of ourknowledge, no research about direct BSA determination based on EIS had been published. Scheme 1 shows the fabrication steps and the interaction of BSA and synthesized electrode. After optimization of experimental parameters pH=8 and incubation time 35 min was adopted for complete immobilization of BSA. Figure 2 a displayed the EIS spectra of TDSN-CGNP-PDDAGE after incubated with different concentration of BSA in 0.1 mol L-1 PBS (pH=8.0). As can be seen in the Figure 6 b, the Rct was proportional to the concentration of BSA in the range of 9.9×10-12-1.6×10-10 mol L-1. We have prepared a novel type of sensor with good stability and high sensitivity for successfullydetermination of BSA in pure serum using electrochemical impedance spectroscopy. These great results attributed to the high electrode active surface of modified electrode, strong interaction of BSA and PDDA and intrinsic sensitivity of EIS sensors

Keywords:

Bovine serum albumin (BSA) , Electrochemical Impedance Spectroscopy (EIS) , electrostatic interaction