Enhancement of Subcutaneously Transplanted ß Cell Survival Using 3D Stem Cell Spheroids with Proangiogenic and Prosurvival Potential.

Islet transplantation has been demonstrated to be a promising therapy for type 1 diabetes mellitus. Although it is a minimally invasive operating procedure and provides easy access for graft monitoring, subcutaneous transplantation of the islet only has limited therapeutic outcomes, owing to the poor capacity of skin tissue to foster revascularization in a short period. Herein, 3D cell spheroids of clinically accessible umbilical cord blood mesenchymal stem cells and human umbilical vein endothelial cells are formed and employed for codelivery with ß cells subcutaneously. The 3D stem cell spheroids, which can secrete multiple proangiogenic and prosurvival growth factors, induce robust angiogenesis and prevent ß cell graft death, as indicated by the results of in vivo bioluminescent tracking and histological analysis. These experimental data highlight the efficacy of the 3D stem cell spheroids that are fabricated using translationally applicable cell types in promoting the survival and function of subcutaneously transplanted ß cells.

Implication of rapid thermal annealing-induced cracks on the performance of multiple-quantum-well laser diodes.

We investigated the effects of rapid thermal annealing (RTA)-induced cracks on the diode performance fabricated with GaAs-AlGaAs microstructures. These effects were examined and characterized after quantum-well intermixing within an epitaxial structure capped by either SiO2 or SrF2 layers. The results show clearly that the density of surface crackes strongly depends on the atomic interdiffusion between the well and the barrier layers and on the quality of the dielectric caps as well. Moreover, surface-crack correlation with the RTA process an dielectric deposition parameters, and the cracking effects on diode performance were observed and analyzed in detail. The results demonstrate that diode characteristics can be greatly improved by good surface morphology. Most importantly, we explored an effective way of reducing the density of RTA-induced cracks for the dielectrics grown by plasma-enhanced chemical vapor deposition, which was beneficial for dielectric-cap quantum-well disordering.