A Point-of-Care Optical Biosensor for α-Amylase Estimation Using CdS/ZnS Quantum Dots

Pancreatitis is a serious condition characterized by increased in $\alpha $ -amylase concentration in the blood serum. We designed and developed of a point-of-care device for estimating $\alpha $ -amylase levels using CdS/ZnS quantum dots (QDs). QDs were synthesized, capped with polyethylene glycol, and conjugated with starch, a substrate for $\alpha $ -amylase. The quantum quenching effect was determined by adding artificial blood serum (ABS) with varying concentrations of $\alpha $ -amylase. A handheld fluoroscopic device was developed to estimate emission intensities relating to the quantum quenching effects. The device demonstrated excellent sensitivity with an R² value of 0.966 and a detection limit of 49.76 U/L with a linear range of 42-420 U/L. When compared to CNPG3 method, Pearson's correlation coefficient was -0.98, showing an inverse relation to each other. The developed device was tested with ABS. It showed promising results in laboratory conditions. However, the device needs to be clinically validated before deploying for detection of acute pancreatitis, especially in remote areas, and it can be further improvised with wireless technology and spectral sensors.