Magnetic Testis Targeting and Magnetic Hyperthermia for Noninvasive, Controllable Male Contraception via Intravenous Administration.

Mild testicular hyperthermia by the photothermal effect of gold nanorods could realize controllable male contraception. However, associated limitations, such as testicular administration and infrared laser inflicting severe pain, and the nondegradability of nanoparticles potentially causing toxicity, have restricted further clinical application. Inspired by the excellent physicochemical properties of iron oxide nanoparticles (IONPs), and the finding that testicular injection of PEG-coated IONPs with a diameter of 50 nm (PEG@Fe3O4-50) following an alternating magnetic field (AMF) could achieve controllable male contraception; here we propose a noninvasive, targeting approach for male contraception via intravenous administration. The magnetic properties and testes targeting of IONPs were proven to be greatly affected by their surface chemistry and particle size. After systemic administration, citric acid stabilized IONPs with size of 100 nm (CA@Fe3O4-100) were found to be the best ideal thermoagent for realizing the noninvasive contraception. This study offers new strategies for male contraception.