Effect of Integrating Polyethylene Glycol to Alginate-Poly-L-Lysine and Alginate Chitosan Microcapsules for Oral Delivery of Live Cells and Cell Transplant for Therapy

Abstract

Microencapsulation is an emerging technology that has a wide range of applications ranging from drug delivery to tissue engineering. The primary advantages of microencapsulation are that the technology can be used to orally administer drugs directly to the gastrointestinal system and it may eliminate the requirement of immunosuppressant drugs when used in cell therapy procedures. For the technology to be implemented, it is necessary to obtain an appropriate membrane material. Presently, the most commonly used membrane for cell encapsulation is alginate coated with poly-l-lysine, however, there still remains limitations associated with this membrane. The current study investigates the advantages of adding polyethylene glycol (PEG) to the conventionally studied alginate-poly-l-lysine-alginate (APA) and alginate-chitosan (AC) membrane microcapsules. Stability tests using osmotic pressure reveal the addition of PEG to improve mechanical stability of both APA and AC capsules by over 50% which was determined by a decrease in the number of broken capsules when subjected to osmotic pressure. Morphological studies performed in subjecting the capsules to simulated gastrointestinal fluids show that the addition of polyethylene glycol (PEG) prolongs the stability of APA capsules significantly. APA microcapsules disintegrate within 2 hours compared to 24 hours for capsules integrating PEG. Cytotoxicity tests using human HepG2 cells indicate positive MTT showing the membranes containing PEG can support cellular growth. This study implies that incorporating PEG to alginate microcapsules may lead to improvements in the membrane properties for use in oral delivery or transplantation.