The correlation between shape and concentration of silver nanoparticles (AgNPs), their cytotoxicity and formation of reactive oxygen species (ROS) in the presence of electromagnetic fields (EMFs) has been investigated. In addition, the bio-effects caused by the combination of EMFs and graphene nanoparticles (GrNPs) have been also assessed. The AgNPs of three shapes (triangular, spherical and colloidal) and GrNPs were added in high concentrations to the culture of human fibroblasts and exposed to EMF of three different frequencies: 900, 2400 and 7500 MHz. The results demonstrated the dependence of the EMF-induced cytotoxicity on the shape and concentration of AgNPs. The maximal cell killing effect was observed at 900 MHz frequency for NPs of all shapes and concentrations. The highest temperature elevation was observed for GrNPs solution irradiated by EMF of 900 MHz frequency. The exposure to EMF led to significant increase of ROS formation in triangular and colloidal AgNPs solutions. However, no impact of EMF on ROS production was detected for spherical AgNPs. GrNPs demonstrated ROS-protective activity that was dependent on their concentration. Our findings indicate the feasibility to control cytotoxicity of AgNPs by means of EMFs. The effect EMF on the biological activity of AgNPs and GrNPs is reported here for the first time.
Authors would like to thank the company TMSpetsMash Ltd (Kyiv, Ukraine) for providing graphene samples. Special thanks to Dr. Vyacheslav Ogay from National Centre for Biotechnology (Astana, Kazakhstan) for providing cell culture, and to Dr. Timur Abdullin from Kazan Federal University (Russian Federation) for the discussion of the results. In addition, the authors also would like to acknowledge Professor Les Baillie and Professor Adrian Porch (Cardiff University, UK) for the idea of using electromagnetic radiation for the enhancement of the antibacterial properties of silver nanoparticles.
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.
The study was supported by the grant of Ministry of Education and Science of the Republic of Kazakhstan “Nanoparticles-based wound dressings with microwave-enhanced antimicrobial function”: [Grant Number 0113RК00784/N 698], the Royal Academy of Engineering grant “Wound dressings for malodorous chronic ulcers” (Newton UK-Kazakhstan Industry Academia Partnership Programme, UK, project IAPP/1516/12) and FP7 project IRSES-NanoBioMat (TA and SM) and FP7 project IRSES-ENSOR (GK).