Focal adhesion regulation through microcontact printig of protein nanoparticles on self-assembled monolayers for cell guidance

Bacterial inclusion bodies (IBs) are proteinaceous aggregates that are used as nanoparticulate materials to engineer the nanoscale topography. They assist cell culture, proving a positive impact not only on colonization and proliferation, but also on cell morphology. Self-assembled monolayers (SAMs) are formed as a result of a spontaneous self-organization of functionalized organic molecules onto appropriate substrates into stable, well-defined structures. The interaction between different types of SAMs and IBs was studied: different selfassembled molecules give place to different interactions with IBs. Maleimide and OH terminated SAMs were produced, and this platform, surface functionalization using SAMs combined with IBs, was used to perform preliminary studies of cell guidance. Escherichia coli and Lactococcus lactis IBs were produced, purified and characterized. Microcontact printing (μCP) using a polydimethylsiloxane (PDMS) stamp was carried out to provide a stripe pattern of IBs on the SAMs, thus providing IB substrate scaffolds in a pattern, which assisted growth and guidance of cultured neuroblastoma cells. Actin, nuclei and paxillin staining of the cells was performed and observation with confocal microscopy revealed that focal adhesions (FA) were formed specifically on the IB patterns. Cell alignment on the pattern and cellular bridges were also observed and it was determined that L. lactis IBs promoted more FA formation per cell than E. coli IBs. This new approach opens new horizons in the field of tissue engineering and regenerative medicine towards the development of a new generation of innovative biotechnologically engineered biomaterial