Innovative bioprinting strategies based on two-photon polymerisation

In the recent years, there is a constant increasing need to reproduce with high fidelity the environment of cells, which is crucial for different reasons: modelling a disease in order to test a new drug, better understanding cells’ behaviour and response to certain stimuli, creating devices that can mimic our tissues or organs to avoid animal testing, and so on. This is why the focus on the production of substrates with natural and biocompatible materials is increasing really fast and why this thesis was focused on the creation of a bio-resist with biomimetic features in order to print, via two-photon polymerisation, different substrates which can be used in future works for several biomedical purposes. In parallel with the bio-resist production, testing geometries were designed to optimise the printing process and define the best printing parameters. This first phase of calibration was followed by the design and slicing of 3D geometries that were printed as proof of concept and to asses the reachable spatial resolutions. The final goal of the project was to print a suspension of cells in the home-made bio-resist. To do so, the production steps were adapted to increase cells’ viability and the cell suspension was isolated as much as possible from the printing environment. The development of the resist was carried out inside an incubator, allowing a strict control of the environment. Unfortunately, the printing process of the bio-resist resulted less repeatable than expected and there is still the need to carry out more tests in order to better control and optimise the production of the resist but, due to the lack of time, it was impossible to perform them during this project. Moreover, the cell viability was sometimes compromised by the scanning laser during the printing process. Ideally, once these problems will be overcome, the approach could be used for several purposes, such as the production of drug delivery systems or to reproduce, with increased fidelity, the environment of cells, with the final aim of studying cells’ interaction with the extracellular matrix or to test and model a disease.