German researchers from the Institute for Integrative Nanosciences at IFW Dresden have developed micro-motors, which can deliver poorly swimming sperms to the oocyte for fertilization. The so-called “spermbots” were printed using Nanoscribe´s Photonic Professional GT system. They consist of tiny metal helices, controlled by a rotating magnetic field. The groundbreaking results have recently been published in ACS Journal Nano Letters.
You can see a movie of the spermbots below (Prof. Oliver G. Schmidt, Dr. Mariana Medina Sánchez, Lukas Schwarz et al., IFW Dresden)
Spermbot with an oocyte (O. Schmidt, Leibniz Institute for Solid State and Materials Research Dresden (IFW))
Origin of the spermbots
One of the main causes of infertility is low sperm motility, meaning that the sperms are healthy but can’t swim. After the theoretical development of these spermbots, the researchers faced the challenge of actually implementing the results in practice. They decided to use 3D laser lithography. This innovative technology enabled them to fabricate such tiny objects in almost any shape and with the highest precision. In accordance with the data generated from a digital model, the computer-aided laser beam has written three-dimensionally in liquid photoresist. During this writing or rather printing process – the so-called two photon polymerization – the photosensitive resist cures in the exposed areas. The excess resist can later be removed easily in a developing bath. The plastic helices printed from a photopolymer with this technique were additionally coated with a metal layer to achieve magnetic properties. Thus, the spermbots can be controlled and moved to the oocyte by a rotating magnetic field.