# The Biocompatibility of Wireless Power Charging System on Human Neural Cells
###### Abstract  
The progress in technology and science leads to the invention and use of many electrical devices in the daily lives of humans. In addition to that, people have been easily exposed to increased newly generated artificial electromagnetic waves. Exponential use of modern electronic devices has automatically led to increase in electromagnetic wave exposure. Therefore, we constructed the prototype of wireless power charging system to study the biocompatibility of electromagnetic field (EMF) generated by this system on various human cell lines. There are many studies indicating the negative bio-effect of EMF on various types of cells, such as induction of apoptosis. From the other point of view, these effects could rather be beneficial in the way, that they could eliminate the progress of various diseases or disorders. For that reason, we compared the impact of EMF (87 kHz, 0.3-1.2 mT, 30 min) on human normal as well as cancer cell lines based on morphological and cellular level. Our results suggested that EMF generated by wireless power charging systems does not have any detrimental effect on cell morphology, viability and cytoskeletal structures of human neural cells. oe 2021 11 3611 11  
the detailed knowledge regarding the mechanism of the effects of RF-EMF on biological processes has not been elucidated clearly. Some recent studies highlighted that RF-EMF produced from mobile phones is absorbed by the brain in level, which can affect its activity [4; 14]. Additionally, the increased thermal effect of RF-EMF on neural cells could lead to changes in some physiological functions of neuronal cells [15; 16]. Electromagnetic waves are generated using various electronic devices. Living systems can absorb produced waves. These waves cause vibration of polar or charged molecules, which are components of plasma membrane or cytoplasm of cells. Therefore, RF-EMF could be critical to human health and safety. Based on this, specific absorption rate (SAR) standards were specified by International Commission on Non-Ionizing Radiation Protection (ICNIRP). SAR refers to the amount of ratio wave energy absorbed by unit mass of human body (W/kg). ICNIRP has adopted a conservative position and uses 4 W/kg averaged over 30 min as the RF-EMF exposure level [17; 18]. To ensure that thermal effects are avoided, safety factors have been incorporated into exposure limits, resulting in whole-body-averaged limits of SAR to 0.08 and 4 W/kg in uncontrolled and controlled environments, respectively [17]. As the wireless charging becomes an increasingly discussed issue addressed not only by academic researchers, but also by industrial subjects, standardization is required for a smooth and reliable commercialization. It should allow interoperability between different chargers and increase safety. Therefore, the standards must include safety and efficiency criteria, EMF limits, and interoperability targets along with wireless charging testing. Among the most important standards for WPT is SAE TIR J2954/2 [19], which is concerned with alignment methods, interoperability, and frequency band and power levels. It establishes the efficiency greater than 90% when using matched coils and higher than 85% when using interoperable systems. Since the wireless charging is accompanied by an intermediate to high-frequency EMF, it is also necessary to instruct the EMF levels. Another guideline is established in IEEE Standard for safety levels with respect to human exposure to RF-EMF, 3 kHz to 300 GHz [20]. Several studies focused on the possible impact of electromagnetic waves generated by EMF on neurons have recently been published with great interest, especially in relation to brain tumor development [1]. In addition, the increased risk observed in some of the epidemiological studies is inconsistent with the stable frequency of occurrence of oncological diseases in the population. There are discussable results according to experimental conditions, models of study or used methods.