Hydrophilic and Insoluble Electrospun Cellulose Acetate Fiber-Based Biosensing Platform for 25-Hydroxy Vitamin-D₃ Detection

The present work describes the fabrication of a simple, low-cost, eco-friendly, and disposable conducting paper substrate (RCP) decorated with electrospun cellulose acetate fibers (CAEFs) for biosensor application. CAEFs were electrospun under spinning conditions at a voltage of 16 kV, flow rate of 0.2 mL h–1, and tip-to-collector distance of 15 cm. CAEFs were directly collected onto RCP. A scanning electron microscopy study revealed the diameter of CAEFs in the range of 330 ± 3.50 nm. The contact angle of CAEFs was found to be 38.07 ± 5.10°, which indicates a hydrophilic nature of the fibers. Further, the CAEF/RCP electrode was modified with antibody specific to 25-hydroxy vitamin-D3 (AB-25OHD3), followed with bovine serum albumin (BSA) to block nonspecific binding sites for detection of 25-OH vitamin-D3. The BSA/AB-25OHD3/CAEF/RCP immunoelectrode fabrication was confirmed thorough scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle and electrochemical techniques. The chronoamperometry response study of the BSA/AB-25OHD3/CAEF/RCP immunoelectrode toward 25-OHD3 detection showed the lowest detection of 10.0 ng mL–1, sensitivity of 0.16 μA ng–1 mL cm–2, and the linear range of 10–100 ng mL–1. This immunoelectrode did not show any interference effect resulted in the higher selectivity for 25-OHD3. The concentration of 25-OHD3 obtained from ELISA of the serum samples collected from the healthy persons showed good agreement with results of validation studies conducted on the BSA/AB-25OHD3/CAEF/RCP immunoelectrode.