Research Progress of Nano Copper Lubricant Additives on Engineering Tribology

Nanoparticles have as characteristics super sliding, extreme pressure, self-healing, etc., which can improve the friction reduction and anti-wear performance of sliding components, when used as lubricating oil additives. Nano-copper particles have a good synergistic effect with other antifriction agents, anti-wear agents, antioxidants and grease additives because of their low shear strength and grain boundary slip effect, showing a better anti-friction and anti-wear effect. However, nanoparticles are prone to conglomerate, and this causes a bottleneck in the application of dispersant for nano-copper in a lubricating oil system. The regulation of nanosized effect and surface properties has great engineering significance in compensating for the precision in manufacturing accuracy. This paper comprehensively reviews the tribological research progress of nano-copper as a lubricant additive, which provides a reference to the application of nano-copper particles as lubricating oil additives on engineering tribology.

Size dependent inhibition of sperm motility by copper particles as a path towards reversible male contraception

Effective inhibition of sperm motility using a spermicide can be a promising approach in developing non-invasive male contraceptive agents. Copper is known to have contraceptive properties and has been used clinically for decades as intrauterine contraceptive devices (IUDs) for contraception in females. Beyond that, the spermicidal use of copper has not been explored much further, even though its use could also subdue the harmful effects caused by the hormonal contraceptive agents on the environment. Herein, we study the size, concentration and time dependent in vitro inhibition of bovine spermatozoa by copper microparticles. The effectivity in inhibiting the sperm motility is correlated to the amount of Cu2+ ions released by the particles during incubation. The copper particles cause direct suppression of sperm cell motility upon incubation and thereby show potential as sperm inhibiting, hormone free candidate for male contraception beyond condoms.