Adaptation of a Bacterial Bioluminescent Assay to Monitor Bioeffects of Gold Nanoparticles.

Moustafa R Yehia,Tatyana E Smolyarova,Alexandr V Shabanov,Nadezhda S Kudryasheva,Ekaterina S Sushko,Gennady A Badun

doi:10.3390/bioengineering9020061

Moustafa R Yehia, Tatyana E Smolyarova + Show 4 more

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https://doi.org/10.3390/bioengineering9020061

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Abstract

Our current study aimed to adapt a bioluminescent bacteria-based bioassay to monitor the bioeffects of gold nanoparticles (AuNPs). Luminous marine bacteria Photobacterium phosphoreum and AuNPs modified with polyvinylpyrrolidone were employed; low-concentration (≤10−3 g/L) bioeffects of AuNPs were studied. Bioluminescence intensity was used as an indicator of physiological activity in bacteria. Two additional methods were used: reactive oxygen species (ROS) content was estimated with a chemiluminescent luminol method, and bacterial size was monitored using electron microscopy. The bacterial bioluminescent response to AuNPs corresponded to the “hormesis” model and involved time-dependent bioluminescence activation, as well as a pronounced increase in the number of enlarged bacteria. We found negative correlations between the time courses of bioluminescence and the ROS content in bacterial suspensions, demonstrating the relationship between bioluminescence activation and bacterial ROS consumption. The combined effects of AuNPs and a beta-emitting radionuclide, tritium, revealed suppression of bacterial bioluminescent activity (as compared to their individual effects) and a reduced percentage of enlarged bacteria. Therefore, we demonstrated that our bacteria-based bioluminescence assay is an appropriate tool to study the bioeffects of AuNPs; the bioeffects can be further classified within a unified framework for rapid bioassessment.

Highlights

IntroductionWe found negative correlations between the time courses of bioluminescence and the reactive oxygen species (ROS) content in bacterial suspensions, demonstrating the relationship between bioluminescence activation and bacterial ROS consumption
We further demonstrated an active role of reactive oxygen species (ROS) in the bioeffects of fullerenol NPs [56]; ROS content was monitored using the chemiluminescence luminol method [59,60]
While the deviations (Figure 1A) may seem stochastic, they are valuable when considered through the hormesis model, which supposes a nonlinear dependency of bioeffects on dosage (Figure 1B)

Summary

Introduction

We found negative correlations between the time courses of bioluminescence and the ROS content in bacterial suspensions, demonstrating the relationship between bioluminescence activation and bacterial ROS consumption. The combined effects of AuNPs and a beta-emitting radionuclide, tritium, revealed suppression of bacterial bioluminescent activity (as compared to their individual effects) and a reduced percentage of enlarged bacteria. It is recognized that materials at the nanoscale possess unique optical, magnetic, catalytic, and electronic properties that differ from those of their bulk form [1,2,3,4]. These properties can be exploited to tackle a host of industrial, medical, and research problems

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