Fast Broad-Spectrum Staining and Photodynamic Inhibition of Pathogenic Microorganisms by a Water-Soluble Aggregation-Induced Emission Photosensitizer.

Qi Zhou,Siyu Lu,Xianglong Hu,Bing Cao,Xiaoming Lyu,Jiarui Zhao,Xueping Liu,Jing Liu,Meixiao Zhan

doi:10.3389/fchem.2021.755419

Abstract

Pathogenic microorganisms pose great challenges to public health, which is constantly urgent to develop extra strategies for the fast staining and efficient treatments. In addition, once bacteria form stubborn biofilm, extracellular polymeric substance (EPS) within biofilm can act as protective barriers to prevent external damage and inward diffusion of traditional antibiotics, which makes it frequently develop drug-resistant ones and even hard to treat. Therefore, it is imperative to develop more efficient methods for the imaging/detection and efficient inhibition of pathogenic microorganisms. Here, a water-soluble aggregation-induced emission (AIE)-active photosensitizer TPA-PyOH was employed for fast imaging and photodynamic treatment of several typical pathogens, such as S. aureus, methicillin-resistant Staphylococcus aureus, L. monocytogenes, C. albicans, and E. coli. TPA-PyOH was non-fluorescent in water, upon incubation with pathogen, positively charged TPA-PyOH rapidly adhered to pathogenic membrane, thus the molecular motion of TPA-PyOH was restricted to exhibit AIE-active fluorescence for turn-on imaging with minimal background. Upon further white light irradiation, efficient reactive oxygen species (ROS) was in-situ generated to damage the membrane and inhibit the pathogen eventually. Furthermore, S. aureus biofilm could be suppressed in vitro. Thus, water-soluble TPA-PyOH was a potent AIE-active photosensitizer for fast fluorescent imaging with minimal background and photodynamic inhibition of pathogenic microorganisms.

Highlights

Pathogenic microorganisms, especially drug-resistant bacteria, are posing more and more severe threat to human health in last decades. (Bartell et al, 2019; Kang et al, 2019) According to the World Health Organization, bacterial infection caused highest death rate in less developed countries in the past 15 years. (Wang Y. et al, 2020) Due to the high infectivity and mortality of bacteria, bacterial infection threats the public health and economic development all over the world
The insert fluorescent image of sample at 99% exhibited remarkable orange red fluorescence compared to its pure aqueous solution
The aggregationinduced emission (AIE) cure of TPA-PyOH definitely indicated its AIE characteristics (Figure 2C), which was well consistent with some reported AIE systems. (Li et al, 2018; Wang et al, 2020b)

Summary

INTRODUCTION

Pathogenic microorganisms, especially drug-resistant bacteria, are posing more and more severe threat to human health in last decades. (Bartell et al, 2019; Kang et al, 2019) According to the World Health Organization, bacterial infection caused highest death rate in less developed countries in the past 15 years. (Wang Y. et al, 2020) Due to the high infectivity and mortality of bacteria, bacterial infection threats the public health and economic development all over the world. The microorganism dispersions were co-incubated with TPA-PyOH (2.5 μM or 5 μM) or PBS for 5 min at 37°C, respectively. Microorganism suspension (100 μl) was added to the diluted TPA-PyOH dispersion (100 μl) at 96-well plates, and the mixture was incubated at 37°C for 30 min. After incubating for 2 h, the mixture was treated with white light irradiation (∼38.6 mW/cm min) or kept at dark in the whole process, the residual biofilms were rinsed with PBS buffer for three times. After irradiation by white light or at dark, the residual biofilm was washed by PBS buffer and stained by the LIVE/DEAD BacLight bacterial viability kit. The supernatant was collected and the absorbance at 540 nm was recorded by a microplate reader

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT