Dr. Jahangir Ahmad Rather
Department of Chemistry, Sultan Qaboos University, Oman
Title: Graphene amplified femtosensitive aptasensing of estradiol an endocrine disruptor
Abstract:
We report the construction of novel electrochemical femtomolar aptasensing APT–ERGO/GCE interface
based on covalent immobilization of 38-mer amine functionalized (NH2–APT) 17β-estradiol (E2) DNA aptamers
on graphene as an amplifying platform. The graphene oxide (GO) was synthesized and characterized by using
FTIR, UV-vis, XRD spectroscopy and SEM techniques. The strategies for construction of E2 aptasensing
interface comprises by three steps modification process; (i) electrochemical reduction of GO on the GCE electrode
to form ERGO/GCE. (ii) The E2-aptamers (NH2–APT) were further immobilized on surface of ERGO/GCE
interface by using electrochemical reduction of surface-functionalized diazonium salts as an impact strategy. The
procedure includes electrografting of ERGO/GCE by electrochemical reduction of diazonium salt (ClN2
+–Ph–
COOH) to give ERGO/GCE–Ph–COOH modified electrode. (iii) The free carboxyl groups of ERGO/GCE–Ph–
COOH surface were conjugated with NH2–APT by application of carbodiimide chemistry to give an aptasensing
APT–ERGO/GCE interface. The presence of ERGO as an amplifying platform causes successful immobilization
of E2-aptamers with a surface coverage of 1.9 × 1013 molecule cm−2, which is higher than reported methods. The
constructed aptasensing APT–ERGO/GCE interface was appraised using cyclic voltammetry (CV) and
electrochemical impedance spectroscopy (EIS). The synergetic effect of high affinity and specificity of
E2-aptamers and graphene, which produce a novel femtosensitive label-free electrochemical aptasensing
APT–ERGO/GCE interface for the detection of [E2]. The oxidation peak currents at aptasensing
APT–ERGO/GCE interface was proportional to [E2] over two different concentration linearity ranges, 1.0 × 10-
15 molL-1
to 9.0 × 10-12 molL-1
and 1.2 × 10-11 molL-1
to 2.3 ×10-10 molL-1
respectively, with a limit of detection
(LOD) of 0.5 × 10-15 molL-1
. This aptasensing APT–ERGO/GCE interface was offered as a femtomolar tool for
the determination of [E2] in environmental and pharmaceutical samples such as wastewater (spiked) and
pharmaceutical dosages.
Biography:
Career Objective
Aspiring for a competitive and challenging environment to obtain a position where I can apply acquired knowledge and skills and working in a team environment, there by continuously growing and contributing to the main objectives of the organization.
Current Research Activities
Development of Aptasensors for the monitoring of toxic endocrine disruptors (EDCs) in wastewater.
Muftifunctional Biolectrochemical System for real-time performance for desalination, hydrogen production and wastewater treatment.