Clinically comparable impedimetric immunosensor for serum alkaline phosphatase detection based on electrochemically...

In this work, we demonstrate label-free electrochemical impedance spectroscopy (EIS) based alkaline phosphatase (ALP) detection using gold nanoparticles (AuNPs), electrochemically engineered Au-nano-Dendroids, and graphene oxide (GO) nanocomposite. These nanomaterials were sequentially deposited on to the screen-printed carbon electrode (SPCE) and antibodies against ALP (anti-ALP) were immobilized using carbodiimide bioconjugation process. The sensor probe has been characterized extensively using TEM, EDX, SAED, XRD, FE-SEM, FTIR, DIC, and electrochemical techniques. The analytical performance of fabricated biosensor has been evaluated using EIS, where linear dynamic range and limit of detection were obtained to be 100-1000 U/L and 9.10 (±0.12) U/L, respectively. The developed biosensor showed high selectivity towards ALP with negligible interference (k_sel « 1; n = 3) due to coexisting molecules. The sensor probe has successfully recovered ALP between 108.84% and 172.50% (n = 3) in human serum samples. The sensor has been used to estimate ALP in clinical serum samples, where the level was found to be 83.15 U/L and was comparable with standard technique used in the hospitals. The shelf life, stability, and reproducibility have also been evaluated.