Investigation of alginate-ε-poly-L-lysine microcapsules for cell microencapsulation

Cell microencapsulation is a promising approach for cell implantation, cell-based gene therapy, and large-scale cell culture. The well-studied α-AP (alginate-α-poly-L-lysine) microcapsules have been restricted to large-scale cell-culture and clinical applications because of high costs and cytotoxic effects in some cases. This study used ε-poly-L-lysine (ε-PLL), a high-biocompatible and low-cost food additives produced by fermentation, to prepare ε-AP (alginate-ε-PLL) microcapsules with various thickness membranes and swelling behaviors. ε-AP microcapsules were permeable to BSA, a standard protein of culture medium. ε-AP-microencapsulated Chinese hamster ovary (CHO) cells proliferated with culture time; no obvious difference with α-AP-microencapsulated CHO cells during the early 19 days. Whereas ε-AP-microencapsulated CHO cells kept higher viability (OD = 0.646 ± 0.012) on the 22nd day and microcapsule strength (integrity rate of 88%) on the 24th day than that of α-AP microcapsules (OD = 0.558 ± 0.025, integrity rate of 80%). ε-AP (alginate-ε-PLL) microcapsules exhibited more superior properties and could lower the costs to broaden the applications of microencapsulation technology.