ABSTRACT
Objective@#To explore an open porous microtissue which is suitable for the growth of bone marrow mesenchymal stem cells (BMSCs) , and the optimal size of this microtissue.@*Methods@#Polymethyl methacrylate (PMMA) micro-stencil array chips with pore diameters of 1500 μm and 800 μm were constructed by laser drilling technique. The gelatin solution was chemically crosslinked and uniformly spread on the micro-stencil array chips. After freeze-drying for 16 h, the microgels in the chip were ejected by the ejector-pin array. SEM images were taken to observe the microstructure of microgels. Pore size and porosity of two kinds of microgels were calculated using Image J Pro software. The P3 BMSCs were seeded on microgels at the concentration of 5×106/ml. After 7 days culture in vitro, the microtissues were obtained. Thereafter, the viability of seeded BMSCs was assessed using live/dead cell assay. The growth of the cells on the microtissues and the secretion of ECM were observed by scanning electron microscopy (SEM).@*Results@#The SEM images showed that the open porous structured microgels were successfully fabricated using the micro-stencil array chip. The pore size and porosity of 1 500 μm microgels were about 1.5 times that of the 800 μm microgels. After 7 days culture in vitro, the number of cells 1 500 μm microgels were more compared to 800 μm microgels, in the live/dead cell assay. Fluorescent quantitative analyses showed that the viability of BMSCs on 1 500 μm microtissues was 4 times that of 800 μm microtissues. SEM images showed that the cells on 1 500 μm microtissues grew well and surrounded by ECM.@*Conclusions@#The micro-stencil array chips were successfully used to construct microgels with open porous, which could be further used to fabricate open porous microtissues. The 1 500 μm microtissues were more favorable for BMSCs, compared to 800 μm microtissues.