Realization of photo-curing gelatin hydrogel using a commercial projector for culturing mesenchymal cells

This paper investigates the realization of synthetic extracellular matrix with visible light photo-patterning gelatin in a simpler manner. A synthetic extracellular matrix provides an initial attachment for the seeded cells on the experimental substrate such as glass plate or multi-well until they realized their the natural extracellular matrix. Here, a commercial Digital Light Projector (DLP) was used to induce gelatin with Rose Bengal as a crosslinking agent to form the thin layer on the experimental substrate. Various gelatin concentrations from 2%-10% were exposed at different times in order to optimize the patterning process. A geometrical characterization on the patterned gelatin, such as contour measurement and resolution, were taken place. Results showed that the thickness of patterned gelatin was in the range of 10 μm - 60 μm depends on the exposure time of the DLP projector. Moreover, a visual method aided by the Fiji toolbox from NIH ImageJ image processing was used to observe the density and spatial arrangement of the cultured cells on the substrate. Ultimately, biocompatibility using MTT assay was also employed to confirm the viability of the cells on the gelatin substrate. The results show that we are able to control the physical and spatial arrangement of the gelatin substrate, and they with cell viability depend on 6 days of observation. It was found that the gelatin substrate provides faster growth on cultured cells compared to the control study. This finding leads to the possibility to realize the automation system in cell culture technology with an affordable investment.