Mariana Medina Sánchez studied Mechatronics Engineering at the Universidad de San Buenaventura (Colombia) from 1999 to 2005. She was working as assistant professor and researcher from 2005 to 2009 at the same University. In 2009, Mariana traveled to Barcelona (Spain) to start her postgraduate studies at the Nanobioelectronics and Biosensors Group (Institut Català de Nanotecnologia –ICN-, Universitat Autònoma de Barcelona –UAB-), where she got her Master’s degree in Nanotechnology, working on “Nanobioelectronics-based platforms for lab-on- a-chip applications” with Prof. Arben Merkoçi. Then, she continued with her PhD studies on Biotechnology at the same Institute, developing nanobioelectronics-based platforms for lab-on- a-chip applications. During her PhD, Mariana worked in the performance of an ultrasensitive pesticide sensor using boron-doped diamond electrodes, in collaboration with Prof. Yasuaki Einaga, from Keio University (Japan). She also developed an inkjet-printed transistor as biosensing platform onto a flexible substrate for protein detection, in close cooperation with Prof. Eloi Ramon from the Institut de Microelectrònica de Barcelona (IMB-CNM, CSIC). In February 2014, she moved to Dresden (Germany) for working as postdoctoral researcher at the Leibniz Institute for Solid State and Materials Research Dresden (with Prof. Oliver Schmidt as director). For 2 years, Mariana has been working on the fabrication of integrated rolled-up microelectrodes for DNA detection, as well as in the design, production and control of tiny polymeric micromotors for biomedical applications. Recently, in February (this year), she was promoted as a group leader of the Nano-Micro- Biomedical Engineering Group at the same Institute. She continues working in the development of micromotors that help sperm cells to carry out the fertilization task towards in vivo application, as well as in the development of innovative rolled-up impedimetric biosensors for single cell tomography.
Sperm-carrying micromotors, so-called Spermbots, are tiny motors with sizes in the micrometer range, made from advanced functional and biocompatible materials, to help sperm cells carry out their intended function in a natural microenvironment, even when there are few sperms or when sperms are not physically strong enough to swim through the female reproductive tract to reach the fertilization site. These two sperm deficiencies are the main causes of male infertility, diagnosed in about 30 % of the cases. Up to now, these problems have been mainly addressed by artificial insemination and in vitro fertilization. Artificial insemination is a relatively inexpensive and simple technique that involves introducing sperm to a woman’s uterus with a medical instrument but its success rate is under 30 percent. In contrast, the in vitro fertilization can be more effective but it is more complicated and expensive. It requires removing eggs from a woman’s ovaries with a needle, fertilizing them outside the body and then transferring the embryos to her uterus or a surrogate’s a few days later. With Spermbots we aim to enhance the success rate of the artificial insemination, which take place in in vivo conditions. For achieving this goal, two different microrobotic devices will be presented: The first one is based on a rolled-up magnetic thermoresponsive tube that serves to capture a motile sperm, direct its motion toward the oocyte, and release it there. The second one is a customized microhelix that is able to actively collect an immotile sperm, carry it to the oocyte, and release the sperm to let it fuse with the oocyte cell membrane. Those micromotors are suitable for these tasks due to potent, controllable and no harmful 3D motion behavior that is directed by an external magnetic field controller. The potential of this novel approach toward assisted reproduction will be put into a perspective without forgetting some of the remained challenges that we still need to address to achieve successful fertilization by using artificially motorized/guided sperms.