[16p-B4-1~13] 4.1 Plasmonics and Nanophotonics

4:45 PM - 5:00 PM JST(7:45 AM - 8:00 AM UTC)English Presentation

[16p-B4-13] Polyaniline coated U-bent Fiber Optic Aptasensor for Arsenite Detection in Environmental Matrices

〇(DC)Ashish Shukla¹, Tathagata Pal¹, Soumyo Mukherji¹ (1.IIT Bombay, Mumbai)

Keywords:

aptamer,optical fiber,polyaniline

Arsenic has been a serious contaminant for decades and is currently affecting millions of people living in multiple countries. There is a need for a simple cost-efficient sensing methodology. Optical fiber-based sensing platform is highly sensitive, cost-efficient and has a myriad of merits. Aptamer as a bio-receptor is a very selective, cost-efficient means for detecting small target analyte such as arsenite oxyanion. In the current work, we have developed an aptamer immobilized on a polyaniline-coated U-bent fiber-optic sensor for the detection of arsenite oxyanion in various environmental matrices. The synergistic combination of specificity from aptamer and sensitive combination of polyaniline coating and U-bent optical fiber gives the sensing probe its ability to detect arsenite in complex water matrices. Under the provided conditions, the arsenic-specific aptamer undergoes formation of tertiary structure that specifically binds to arsenite. The optimization of aptamer folding conditions resulted in the sensitive binding of arsenite oxyanion. The exposed sites on the fiber core were blocked away by utilizing hexyl amine to avoid cross-sensitivity. We were able to get an experimental detection limit of arsenite to as low as 1 ppb in complex environment matrices such as lake water, tap water, etc. The sensing probe gave R²>0.99 and a linear range of operation in the range from 1 ppb to 1000 ppb (in log scale). The developed optical fiber aptasensor demonstrates great promise for widescale field deployable arsenic biosensing at low cost.