Fabrication and Construction of Highly Sensitive Polymeric Nanoparticle-Based Electrochemical Biosensor for Asparagine Detection

This work reports a highly sensitive, selective, and stable nanoparticle-based electrochemical biosensor with modified ammonium (NH4+) ion-sensing electrode as a transducer for asparagine detection. The biosensor was developed on the bioassay principle of hydrolysis of L-asparagine into L-aspartate and ammonia by immobilized Lasparaginase (biocomponent). The released ammonium ions were detected by a potential change in nylon membrane-coated ion-sensitive electrode (ISE) having L-asparaginase entrapped in chitosan alginate (CA) nanoparticle. The L-asparaginase (purified)with 44.4 IU/mg specific activity was obtained from Phyllanthusemblica leaves.The CA nanoparticles containing L-asparaginase with 83.5% entrapment efficiency and 360 nm size were attained by ionic gelation method. In optimum conditions, the fabricatedelectrochemical biosensor showed sensitivity with a detection limit of 1.69x 10-10 M within a response time of 3 min. The biosensor demonstrated advanced performance analysis in terms of reproducibility, reversibility, stability, and selectivity. The proposed biosensor can be potentially employed for L-asparagine determination in the leukemia diagnosis and treatment. Furthermore, the developed biosensor could act as a food quality monitoring device in the food industry.