On-slide cell adhesion and cytocompatible (ultra)thin microparticles detachment

• Autor(a) principal: Coelho, Manuel Luís da Silva
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/33252
• topic: Ultrathin microparticles; Omniphilic–omniphobic patterned surfaces; Wettabledewettable contrast; Bioinspired surfaces; Cytocompatible microparticles detachment

Ultrathin structures showcasing high aspect ratio are a versatile class of materials that have facilitated the development of new nanotechnological concepts. Catalysis, energy harvesting, and biomedicine are some of the fields where these structures have been applied. However, effective efforts to precisely control lateral dimensions and geometries of such reduce dimensions are scarce. Recently, new applications for these materials have been found in the field of biomedicine. Due to their high aspect ratio, thin and ultrathin materials show the potential to outperform their bulk counterparts. The control over dimensions and architectures of the material at a nanoscale has allowed attaining structural properties including electrical transport, flexibility, optical effects, which were not showcased by bulk counterparts. The project developed here adds on to a previous study that described the production of microparticles showcasing (i) highly controlled lateral size (ranging from 100 um to the millimeter scale), (ii) nanometric thickness (in the range of hundreds of nanometers), and (iii) versatile shape, using pre-patterned oleophilic-oleophobic surfaces. The use of such surfaces did not enable the cytocompatible detachment of the particles, which was dependent on the use of solutions with high pH. The hypothesis of this project was that the use of omniphobic-omniphilic patterned surfaces would enable the detachment of microparticles produced from biodegradable polymers valuable for biomedical applications, namely poly-ε-caprolactone (PCL). The ability to detach microparticles in mild conditions was expected to allow the development of an all-in-one system to obtain monodisperse thin microparticles laden with adhered living cells. Free-standing square-shaped PCL microparticles with lateral size of 350 μm and average 401±122, 944±285 and 1318±265 nm thickness at 5, 7 and 9% (w/v) PCL concentration, respectively, were obtained by adapting a previously described dipping method to the preparation of watersoluble sacrificial layers onto wettable regions of omniphobic-omniphilic patterned surfaces. Human mesenchymal stem cells derived from the adipose tissue could be patterned onto on-chip dried thin microparticles, and the constructs thin particles + cells could be retrieved in a cytocompatible manner. The obtained constructs may be used in future approaches as pro-regenerative injectable and low-mass building blocks for tissue regeneration, and may also be used as platform to understand the role of biophysical cues on the biology of adherent cells.