Title: Colorimetric label-free Nano sensor for improved sensitive lead detection in water utilizing unmodified AuNP: Insight into rational design of Pb2+zyme

Biography:

Abdul Ghaffar Memon is Tsinghua University graduate, He earned doctoral degree as Ph.D. in the Environmental Science and Engineering from the School of Environment. Upon his excellence in academics Dr. Memon was awarded as outstanding Ph.D. graduate of year 2019. Dr. Memon contributed in the scientific community through his novel research which is acknowledged and published in high-quality Journals including Journal of Hazardous Materials, ACS Applied Interfaces, Sensors Actuators, B Chem, Biosensors, Frontiers of Environmental Science and Engineering etc. Dr. Memon remained active participant in international conferences, His research was acknowledged with best posters awards. Dr. Memon is recipient of Tsinghua-Veolia top grade scholarship, Chinese government Scholarship, Tsinghua University research grant to participate at international meetings overseas. Dr. Memon participated and represented at various forums including United Nations programs, MCCCOP-I, MCCCOP-II, UNCCD, Belt and Road Initiatives, He remained International Students Ambassador, public speaker, associated with various organizations including TEDxTHU. He is member of American Society for Microbiology (ASM), Pakistan Society for Microbiology (PSM), Biological Safety Association of Pakistan (BSAP), Biosensors Biochip and Nanobiology (BBN), Tsinghua University Student association of Belt and Road Initiative (SABRI), Currently Dr. Memon is serving at NED University of Engineering and Technology as Assistant Professor and contributing in teaching and research at graduate and post graduate level.

Abstract

Water pollution accidents caused by the lead contamination, such as Flint water crisis in the United States, strongly pushed the public to concern the safety of the drinking water distribution system. As a prerequisite, the routine monitoring of lead in water is highly required and demands for an efficient, sensitive, cost-effective, and reliable lead detection methods. This study reports a label-free colorimetric nanosensor using unmodified gold nanoparticles (AuNPs) as indicators to enable rapid and ultrasensitive detection of lead in environmental water. The 8-17 DNAzyme was truncated in this study to facilitate the detachment of ssDNA fragments after the substrate cleavage upon Pb2+ presence. The detached fragments got adsorbed over AuNPs and protected their aggregation against induced salt concentration. As expected, more Pb2+ would result in a stronger color change from blue to pink. The established sensing principle achieved a sensitive limit of detection (LOD) of Pb2+ as 0.2 nM with a linear working range of two orders of magnitude from 0.5 nM to 5.0 nM. The selectivity of nanosensor was demonstrated by evaluating against interfering metal ions. The developed nanosensor can serve as a substitute for rapid analysis and monitoring trace lead levels under the drinking water distribution system and even other environmental water samples.