Motility enhancement of human spermatozoa using electrical stimulation in the nano-Ampere range with enzymatic biofuel cells

Abstract

Sperm motility is a crucial factor for normal fertilisation that is partly supported by mitochondrial activity. Enzymatic biofuel cells (EBFCs) generate electric currents by an electron grade from anodic to cathodic electrodes in a culture media. We demonstrate that electrical stimulation by EBFC at the nano-Ampere range enhances sperm motility that can potentially allow the development of a new therapeutic tool for male infertility, including poor motility. EBFC was set up with three different electrical currents (112 nA/cm2 and 250 nA/cm2) at two different times (1 h, 2 h). Each sample was evaluated for its motility by computer-assisted sperm analyses and sperm viability testing. In the expanded study, we used the optimal electrical current of the EBFC system to treat asthenozoospermia and sperm with 0% motility. Results showed that optimal electrical stimulation schemes with EBFCs enhanced sperm motility by 30–40% compared with controls. Activated spermatozoa led to tyrosine phosphorylation in the tail area of the sperm following the electrical stimulation in the nano-Ampere range. However, the electrically stimulated group did not exhibit increased acrosomal reaction rates compared with the control group. In cases related to asthenozoospermia, 40% of motility was recovered following the electrical stimulation at the nano-Ampere range. However, motility is not recovered in sperm with 0% motility. In conclusion, we found that sperm motility was enhanced by exposure to electrical currents in the nano-Ampere range induced by optimal EBFCs. Electrical stimulation enhanced the motility of the sperm though tyrosine phosphorylation in spermatozoa. Therefore, our results show that electrical currents in the nano-Ampere range can be potentially applied to male infertility therapy as enhancers of sperm motility in assisted reproductive technology.