Self-Assembled Glycobis(acrylamide)-Stabilized Gold Nanoparticles for Fluorescent Turn-on Sensing of Lectin and Escherichia coli
Juby K. Ajish, Anant B. Kanagare, K. S. Ajish Kumar, Mahesh Subramanian, Anand Damodar Ballal, Manmohan Kumar
ACS Applied Nano Materials
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, [email protected], 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 [email protected] 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 [email protected] was further confirmed by steady-state as well as fluorescence lifetime measurements. The [email protected] 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 [email protected] toward Con A was 9.8 × 104 M–1, while the limit of detection was 1.6 nM. The interaction of [email protected] 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.
Absorption, Fluorescence, Ligand binding, Chemical stability, Quenching, Sensors, Nanostructures, Materials