Inhibition of gold nanoparticles (AuNPs) on pathogenic biofilm formation and invasion to host cells.

Qilin Yu,Yueqi Zhang,Jianrong Li,Mingchun Li,Lu Liu,Yufan Wang

doi:10.1038/srep26667

Abstract

Owing to the growing infectious diseases caused by eukaryotic and prokaryotic pathogens, it is urgent to develop novel antimicrobial agents against clinical pathogenic infections. Biofilm formation and invasion into the host cells are vital processes during pathogenic colonization and infection. In this study, we tested the inhibitory effect of Au nanoparticles (AuNPs) on pathogenic growth, biofilm formation and invasion. Interestingly, although the synthesized AuNPs had no significant toxicity to the tested pathogens, Candida albicans and Pseudomonas aeruginosa, the nanoparticles strongly inhibited pathogenic biofilm formation and invasion to dental pulp stem cells (DPSCs). Further investigations revealed that AuNPs abundantly bound to the pathogen cells, which likely contributed to their inhibitory effect on biofilm formation and invasion. Moreover, treatment of AuNPs led to activation of immune response-related genes in DPSCs, which may enhance the activity of host immune system against the pathogens. Zeta potential analysis and polyethylene glycol (PEG)/polyethyleneimine (PEI) coating tests further showed that the interaction between pathogen cells and AuNPs is associated with electrostatic attractions. Our findings shed novel light on the application of nanomaterials in fighting against clinical pathogens, and imply that the traditional growth inhibition test is not the only way to evaluate the drug effect during the screening of antimicrobial agents.

Highlights

Owing to the growing infectious diseases caused by various eukaryotic and prokaryotic pathogens, development of antimicrobial agents is one of the most significant aspects for decreasing pathogenic dangers[1,2,3]
The major stretching frequencies of Au nanoparticles (AuNPs)-S are 3311.88, 2922.72, 2857.21, 1671.57, 1601.62, 1522.77, 1256.50 and 1059.93 cm−1 (Fig. 1c). This indicated the appearance of carbonyl groups, which might be originated from organic acids
We investigated the effect of AuNPs on fungal invasion to dental pulp stem cells (DPSCs) by scanning electron microscopy (SEM) observation

Summary

Introduction

Owing to the growing infectious diseases caused by various eukaryotic and prokaryotic pathogens, development of antimicrobial agents is one of the most significant aspects for decreasing pathogenic dangers[1,2,3]. It is urgent to develop novel and efficient agents and strategies against this eukaryotic pathogen, especially to explore those which have impact on its virulence factors Both eukaryotic and prokaryotic pathogens possess a wide range of virulence factors for their infections, including biofilm formation, invasion to host cells, morphological transition, and stress response[27,28]. The as-synthesized AuNPs had no obvious impact on pathogenic growth, but strongly inhibited pathogenic biofilm formation and invasion, and activated host immune response. These inhibitory effects are associated with the electrostatic attractions between AuNPs and their targeted cells. This study for the first time uncovered the inhibitory effect of AuNPs against pathogenic biofilm formation and invasion, and explored a novel mechanism by which NMs attenuate the virulence of pathogens

Methods

Results

Conclusion