A comparison between LP(GMA) and CLP(GMA) polymer composites as an immobilization matrix for biosensing applications: A model immunosensor for IL 1α.

A comparative study was made by using two matrices (Linear poly(glycidyl methacrylate) (GMA) polymer (LP(GMA)) and carbon black-polyvinylidene fluoride (PVDF)-LP(GMA) composite CLP(GMA)) as immobilization platforms for anti-IL 1α antibody on the development of impedimetric immunosensor for IL 1α biomarker determination. These materials were spin coated onto the clean ITO electrode surface separately and used for IL 1α immunosensor fabrication. Carbon black is utilized as a conductive material and has been employed over the last few decades for electrochemical biosensors development. The using of CLP(GMA) composite as an interface material shows fast electron transfer, when compared to LP(GMA) modified ITO electrode. This comparative study investigated the efficacy of carbon black for impedimetric biosensing. Anti-IL 1α antibodies were utilized as bioreceptors and bound to epoxy groups of GMA polymer. For electrochemical characterizations, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Single Frequency Impedance methods were employed. Furthermore, to follow the antibody attachment on the modified ITO substrates, Fourier Transform Infrared Spectroscopy and Raman spectral techniques were utilized. The morphological characterizations of immunosensor construction stages were carried out by Scanning Electron Microscopy and Atomic Force Microscopy analyses. The sensitive and label-free technique of EIS was used for quantification of IL 1α concentration. Under optimum experimental conditions, the immunosensor had a good linear relationship between impedance values and the IL 1α concentrations ranging from 0.01 to 2 pg/mL and from 0.01 to 3 pg/mL for LP(GMA) and CLP(GMA) modified ITO electrodes, respectively. The results confirmed that CLP(GMA) used in the preparation of the immunosensor illustrated improvements in immunosensor performance, comparing to the LP(GMA) modified immunosensor. Additionally, the immunosensor was successfully applied to evaluate human serum and saliva samples. The obtained results from these samples illustrated the feasibility of the immunosensor for clinical diagnosis in complex biological samples. Also, a simple and low-cost approach was attempted for development of immunosensor with remarkable performance characteristics.

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