Investigation of dopant effect on the electrochemical performance of 1-D polypyrrole nanofibers based glucose biosensor

Abstract

Glucose plays an imperative role in human metabolism and any imbalance in glucose concentration can cause chronic disease like diabetes mellitus. With the drastic increase in the number of diabetic patients around the world, demand for point of care testing device for continuous monitoring of blood glucose level has been accelerated. In this respect, electrochemical glucose biosensors play a vital role for measurement of glucose concentration in human blood. In this work, for the first time, we demonstrate a systematic study of the effect of two different types of dopants viz. lithium perchlorate (LiClO4) and para-toluenesulfonic acid (p-TSA) on the performance of polypyrrole (PPy) based enzymatic glucose biosensor. Both the dopants (LiClO4 and p-TSA) were utilized with the aim of improving the charge transfer capability of PPy films. The PPy nanofibers were synthesized over a Platinum coated glass substrate by electrochemical method. The morphological and electrochemical properties of electrosynthesized PPy nanofibers utilizing template-free method have been tailored by dopant variation (LiClO4 and pTSA) during electropolymerization. The as-prepared PPy nanofibers were used as a support matrix for enzyme immobilization. The as-fabricated enzymatic biosensors were later examined for the detection of glucose. Both the morphological and electrochemical properties of PPy electrode have been observed to improve with p-TSA (PPy–pTSA), as compared to LiClO4 (PPy–LiClO4). The as-fabricated PPy–pTSA/GOx based glucose biosensor has exhibited the highest sensitivity of 6.12 mA cm−2 M−1 with a linear range of 0.1–7.5 mM, which is better as compared to PPy-LiClO4/GOx biosensor. Additionally, the as-prepared PPy–pTSA/GOx biosensor has presented noteworthy stability, selectivity, and reproducibility that validates the importance of the dopant effect in electrosynthesized PPy based biosensing applications.