Title: An on off on fluorescence sensor for the detection of tetracycline and levofloxacin antibiotics

Biography:

Smriti Sri is a 4^th year Ph.D. scholar. She is working under the guidance of Dr. Pratima Solanki, assistant professor, special centre for nanoscience, Jawaharlal Nehru University, New Delhi, India. Her research work focuses on Nanobio interactions, fabrication of biosensors and optical sensor. She has published some of the good papers in her field.

Abstract

A switchable optical sensor based on MoS2 quantum dots (MoS2 qds) was developed to determine two commonly used antibiotics in spiked sample of milk via fluorescence quenching of MoS2 qds by tetracycline (off) and recovery by levofloxacin (On). On adding tetracycline to MoS2 qd the fluorescence gets quenched while on adding levofloxacin the fluorescence reappears. The MoS2 qds were prepared hydrothermally and the average particle size was 4.3±0.42 nm as analysed from TEM. The characterization studies were done using UV visible spectroscopy, fluorescence spectroscopy, FTIR, Time Resolved Fluorescence Spectroscopy (TRFS) and AFM. The sensor detected tetracycline in the range 0.05 to 5 mM with LOD of 0.115 mM and levofloxacin in the range 10 μM to 1 mM with LOD of 22.24 µM. The quenching mechanism is dynamic in nature as analysed with variation in decay time from TRFS. The fluorescence quenching efficiency for tetracycline is 95% while the recovery efficiency is 18% for levofloxacin. The proposed sensor was used to analyse spiked samples of water, sewage and milk and found good accordance with the experimental results. The on off on sensor fabricated here can be used as practical fluorescent sensor for tetracycline and levofloxacin detection.