In the first reporting period, progress on all the planned Work-packages have been made despite delays caused by the current pandemic situation and a complicated pregnancy and parental leave of the PI. For example, in WP1, which is focused on the development of non-destructive devices for the assessment of gametes and embryos, we have fabricated different biosensing platforms for model analyte/sample detection by employing concepts of strain engineering and roll-up origami. We have developed tubular scaffolds for single cell analysis integrating impedimetric sensors for either performing impedance spectroscopy or tomography, allowing the simultaneous detection of single cells and the surrounding media conductivity. Moreover, we have reported the integration of actuators in such tubular-origami microdevices, to allow the gentle capture of oocytes, by demonstrating their functionality with model microobjects of different stiffness. This will then allow the assessment of the mechanical and electrical properties of the zygote membrane as means for detecting factors such as oxidative stress, morphology, zona pellucida thickness, cell metabolism, among other factors. In WP2, there hasve been some progress on stablishing proper cell culture conditions, employing bovine ex-vivo epithelial and ciliary cells, which are then cultured in three dimensional porous scaffolds with dimensions similar as the ones of a real oviduct. Different fabrication technologies are being explored such as 2-photon lithography, Gray lithography combined with plasma etching, and strain engineering to find out the optimal scaffold to create a functional in vitro-mimicking oviduct for the goal of embryo implantation analysis prior and after microrobotic transfer. WP3 deals with the development of untethered microcarriers to transport gamete/zygotes, and here one of the approaches was successfully concluded and published, which consist in a spiral-like micromotor actuated by external rotating magnetic fields which can capture and transport safely a fertilized oocyte from a microenvironment to another, while preserving its viability. The microcarrier was tested in different complex media and confined microfluidic channels, showing promising results. Currently there are two works which are in the phase of Manuscript preparation, one consisting on 3D printed biodegradable microgrippers for the same task, and alginate-based capsule-like micromotors with multiple functionalities. Finally, for WP4 and WP5, a feedback control system guided by ultrasound or optoacoustic is being developed. On one side we have reported on the open loop control of moving magnetically-driven microobjects of sizes similar as the zygote size, in real time and deep tissue employing US and Photoaocustic imaging. We succeeded in tracking such objects in vitro, in ex vivo tissues and in small mice models. In the past months we have been focused on implementing feedback control algorithms based on Machine learning for the precise localization of magnetically-driven microcarriers, making important steps towards their operation in complex and more realistic environments independently on the microcarrier size, velocity, locomotion principle and surrounding environmental factors.
