Floating flower-inspired cell culture platform with simplified medium exchange process based on elasto-capillarity for facilitating cell-surface interaction studies

Abstract

Cells are significantly affected by various extracellular environments showing different cell functions like cell proliferation and differentiation. Thus, many in vitro studies have tried to realize in vivo environments for regulating the functions, especially controlling surface characteristics of cell culture substrates: stiffness, surface topography and ligand density. However, the studies require a large number of cell culture experiments to reveal the cell and surface interactions which lead to increase of cell culture tasks: cell culture substrate preparations, pretreatment and fixation of the substrates in cell culture containers, and medium exchange. Then, the cell culture tasks can impose heavy burdens on experimenters because the tasks are generally labor-intensive and time-consuming. In this study, flower-shape inspired PDMS substrate (FIPS) was developed to facilitate the medium exchange process, mimicking the floating flower’s elasto-capillarity. The FIPS can capture and dispense the medium with reversible closing and opening motions of petals, so that the medium exchange process can be possible with simple pulling up and dipping down of the FIPS. The design of FIPS was determined by elasto-gravity number (EG) which was derived from energy relationship concerned with formation of closed structure. The stable range of EG was investigated through capturing experiments with the FIPSs having different elastic moduli and thicknesses. The FIPS was fabricated through polydimethylsilosane (PDMS) replica molding process using custom-made mold system. Micro-structures also replicated on the surface of the FIPS to show possibility of the surface topography formation with the mold system. The FIPS was evaluated on stabilities of closed structure at two stages: initial capturing stage and long-term maintenance of the closed structure. The results showed that the stable closed structure was formed in some range of EG and the structure was maintained regardless of time progress. NIH3T3 cell proliferation experiments also performed using FIPSs to compare results with conventional method. The proliferation results verified that the FIPS can be used as an alternative cell culture platform for the conventional PDMS substrate for cell-surface interaction studies.