Title
Self-Assembled Glycobis(acrylamide)-Stabilized Gold Nanoparticles for Fluorescent Turn-on Sensing of Lectin and Escherichia coli
Author
Juby K. Ajish, Anant B. Kanagare, K. S. Ajish Kumar, Mahesh Subramanian, Anand Damodar Ballal, Manmohan Kumar
Year
2020
Journal
ACS Applied Nano Materials
Abstract
Gold nanoparticles (AuNPs) with shelf lives of more than 6 months at 25 °C were synthesized by in situ reduction and stabilization using a d-glucose-based bis(acrylamide) solution. Transmission electron microscopy (TEM) images support the homogeneous coating of AuNPs by Glc-bis. In the process, intrinsic emission of self-assembled glycobis(acrylamide) (Glc-bis) was quenched by AuNPs, and the resultant system, Glc-bis@AuNPs, can work as a turn-on sensor, wherein the quenched emission was restored upon the addition of lectin, Concanavalin A (Con A). The aggregation of Glc-bis@AuNPs upon interaction with Con A was pragmatic from the TEM images. The quenching as well as recovery of the emission based on the proximity of AuNPs with Glc-bis in Glc-bis@AuNPs was further confirmed by steady-state as well as fluorescence lifetime measurements. The Glc-bis@AuNPs system was found to be stable up to 1 M NaCl concentration, a factor that fulfills the requirement for biosensing applications. The binding constant of Glc-bis@AuNPs toward Con A was 9.8 × 104 M–1, while the limit of detection was 1.6 nM. The interaction of Glc-bis@AuNPs with a FimH-positive, pathogenic K12 strain of Escherichia coli resulted in restoration of the emission, but experiments with the FimH-negative TOP10 strain did not yield any emission.
Full Article
Instrument
V-650, FP-8500
Keywords
Absorption, Fluorescence, Ligand binding, Chemical stability, Quenching, Sensors, Nanostructures, Materials