Carbene modification and reversible crosslinking of silver nanoparticles for controlled antibacterial activity

Liling Jing,Junying Li,Pengfei Yang,Lian Liu,Wenqiang Sun,Mark G Moloney,Hao Xu

doi:10.1038/s41598-020-72043-1

Abstract

Silver nanoparticles (Ag NPs) system capable of exhibiting different particle size at different temperature was developed, which depended on the extent of Diels–Alder (DA) reaction of bismaleimide with furan. Thus, Ag NPs were functionalized on the surface by a furyl-substituted carbene through an insertion reaction. Subsequent reversible DA crosslinking achieved a controlled aggregation with different particle size, which gives a series of different antibacterial activity. These Ag NPs were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Nanoparticle Size Analyzer. The aggregation of the Ag NPs could be reliably adjusted by varying the temperature of DA/reverse-DA reaction. The antibacterial activity was assessed using the inhibition zone method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which decreased first and then increased in agreement with the size evolution of Ag NPs. This approach opens a new horizon for the carbene chemistry to modify silver nanoparticles with variable size and give controlled antibacterial activity.

Highlights

Silver nanoparticles (Ag NPs) system capable of exhibiting different particle size at different temperature was developed, which depended on the extent of Diels–Alder (DA) reaction of bismaleimide with furan
When Anda et al.[22] investigated the toxicity of Ag NPs to BEAS-2B cells, a type of human lung cells, they showed that small Ag NPs were cytotoxic for human lung cells and the toxicity was associated with the rate of intracellular Ag release, a “Trojan horse” effect, which increased the leakage of cell membrane and lowered cellular activity
As shown in Scheme 1, 4-chloro-4′-hydroxybenzophenone was reacted with furfuryl alcohol in the presence of triphenylphosphine and diethyl azodicarboxylate (DEAD) to give furylsubstituted benzophenone 1, which was subsequently treated with hydrazine monohydrate to generate hydrazone 2 in good yield

Summary

Introduction

Silver nanoparticles (Ag NPs) system capable of exhibiting different particle size at different temperature was developed, which depended on the extent of Diels–Alder (DA) reaction of bismaleimide with furan. It is very hard to adjust the bioactivity of silver-contained materials after it is ready to use That is, it is not easy for Ag NPs to realize controlled drug release that are widely used in the areas of internal treatment[23], regenerative engineering[24], and intelligent medicine[25]. Which was expected to obtain a series of Ag NPs aggregates with controlled size and different antibacterial activity This approach could conveniently realize controlled release behavior by post-treatment instead of synthetic procedure, and might have the potential application to adjust the bioactivity of silver-contained materials after it is ready to use

Methods

Results

Conclusion