Cell transplantation is a way of treatment in which lost cellular functions can be recovered by transplanted cells. However, hypoxic conditions on the transplanted site hinder the survival of the cells. This paper presents an oxygenation device for cell transplantations to improve the engraftment and transplanted cell survival. The flexible and thin polymeric hollow mesh working as gas capillaries can effectively transport oxygen between microvessels and transplanted cells, maintaining adequate oxygen tension for cell survival and functionality. Devices are designed, fabricated, and characterized in this study. Both in silico and in vivo models demonstrate a 4-5 fold increase in cell viability compared to the control group without oxygen-transporting mesh. The results showed that a broad spectrum of cell transplantations could benefit from such MEMS oxygen-transporting device.