Cell-based gene therapy offers an alternative strategy for therapeutic angiogenesis for the management of myocardial infarction (MI). However, immune rejection poses a significant obstacle to the implantation of genetically engineered allogeneic or xenogeneic cells. In the present study, an ex vivo gene therapy approach utilizing cell microencapsulation was employed to deliver vascular endothelial growth factor (VEGF) to ischemic myocardium. Chinese hamster ovary (CHO) cells were genetically modified to secrete VEGF and enveloped into semipermeable microcapsules. In vitro assay indicated that the microencapsulated engineered CHO cells could secrete VEGF as high as 3852 pg ml À1 per 48 h at day 8 after encapsulation. Then the microencapsulated CHO cells were implanted into the injured myocardium in a rat MI model, while engineered CHO cells, blank microcapsules and serum-free culture media were implanted as controls. The humoral immunity to xenogeneic CHO cells were evaluated and we found that the titer of anti-CHO antibodies was significantly lower in the microencapsulated CHO transplantation group than the group receiving unencapsulated CHO cells at two weeks after implantation. However, 1 week later, there was almost no difference between these groups. Histology and western blotting confirmed that the microencapsulated CHO cells maintained their original structure and VEGF secretion three weeks after implantation. The capillary density in the treatment region was also significantly higher in the microencapsulated CHO cell group than control groups, which was consistent with gross heart functional improvement. These data suggest that microencapsulated xenogeneic cell-based gene therapy might be a novel approach for therapeutic angiogenesis in ischemic heart disease.

Transesterification of jatropha oil obtaining process was studied for biodiesel production. Rhizomucor miehei lipase (RML) immobilized on 3-aminopropyltriethoxysilane functionalized magnetic Fe3O4 was employed as a biocatalyst. The immobilized lipase was confirmed by scanning electron microcopy (SEM), Fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM) and confocal laser scanning microscopy (CLSM) techniques. The efficient biodiesel synthesis in ionic liquids using immobilized RML was demonstrated. Fifteen kinds of ionic liquids based on different alkyl chain lengths of the methyl imidazolium cation ([C2MIM], [C4MIM], [C8MIM], [C12MIM] and [C16MIM]) combined with [NTf2], [N(CN)2], [PF6] or [BF4] anions were assayed as reaction media for RML producing biodiesel. The highest synthetic activity of immobilized RML appeared in [BMIM][PF6], which is more than five times higher than the free enzyme. The enzyme catalytic activity remained 60% even after the magnetic nano-biocatalyst and ionic liquid had been reused 5 times in a 48-hour reaction cycle. In addition, the immobilized enzyme exhibited excellent storage stability with almost no decrease in catalytic activity after storing at -20°C for 98 days.