We implemented magnetically actuated polymer−metal
composite helices as microcarriers that can actively capture,
transport, and release single live sperm cells that would
otherwise be immotile due to pathological defects. In order to
set up an environment that would allow these artificially
motorized sperm cells to fertilize an oocyte, we mimicked in
vivo conditions and applied hypoosmotic swelling as a method
for sperm selection in a microfluidic channel platform where we
managed to deliver a single sperm cell to an oocyte cell wall.
Unfortunately, similar to many promising applications in
biomedical engineering, it appears to be still a long way from
artificially motorized sperm delivery to actual oocyte fertilization.
There is a lot of future work to do, considering proper
oocyte culturing, functionalization of helices to create
important biochemical clues, and further improvement of
targeted sperm capture and delivery, in order to achieve a
critical rate of fertilization trials that would lead to successful in
vitro fertilization. It remains to stress that, ultimately, the
strength of this novel fertilization approach lies in its potential
in vivo applicability, since it will not be necessary to explant
(and reimplant) oocytes for artificial reproduction if we can
target and fertilize the oocyte in its natural environment