Investigation of a New Microcapsule Membrane Combining Alginate, Chitosan, Polyethylene Glycol and Poly-L-Lysine for Cell Transplantation Applications

Abstract

Microencapsulation of living cells may serve as an alternative therapy for patients requiring organ transplants. One of the limiting factors in the progress of such therapy is attaining a biocompatible and mechanically stable polymer. The current study investigates the potential of a novel membrane combining alginate, chitosan, polyethylene glycol (PEG) and poly-L-lysine (PLL) with the objective of proposing a membrane suitable for cell entrapment that may overcome some of the shortcomings of the widely studied alginate-poly-L-lysine-alginate (APA) capsules. The novel microcapsule was formulated using a 1.5% alginate solution coated with 0.05% chitosan, 0.1% PEG and 0.05% poly-L-lysine with a final layer of 0.1% alginate. Microcapsules having a diameter of 450 ± 30 μm were prepared. Upon citrate treatment, the membrane remained intact and retained its spherical structure. The membrane was able to support liver cell proliferation and the encapsulated cells were capable of secreting proteins. The study demonstrated that the new membrane can be used for cell entrapment. However, further investigations are needed to assess its potential for long term transplantation and usage in the development of bioartificial organs.

Impact of alginate type and bead diameter on mass transfers and the metabolic activities of encapsulated C3A cells in bioartificial liver applications

“…Due to its relative stability, biocompatibility, adjustable porosity and simplicity of use, alginate is thus a biomaterial of choice when it comes to entrapping cells (Garbayo et al, 2002;Zmora et al, 2002;David et al, 2004a;De Vos et al, 2006;Zimmermann et al, 2007;Wikstrom et al, 2008), to cell therapy (Chang, 2005;Paul et al, 2009) or to being used in medical devices (Ueyama et al, 2002;Orive et al, 2004;Gao et al, 2005;De Vos et al, 2006;Orive et al, 2006;Wikstrom et al, 2008). Some of these studies were conducted with hepatocytes that were either encapsulated within alginate beads (Selden et al, 1999;David et al, 2004b;Gao et al, 2005;Kinasiewicz et al, 2007;Kinasiewicz et al, 2008) or capsules (Canaple et al, 2001;Orive et al, 2004;Haque et al, 2005), or seeded within alginate scaffolds (Zmora et al, 2002;Seo et al, 2006). More specifically, the effects of the type of alginate on human hepatocyte cell line cultures were studied by Khalil et al (2001).…”

Investigation on PEG Integrated Alginate–Chitosan Microcapsules for Myocardial Therapy Using Marrow Stem Cells Genetically Modified by Recombinant Baculovirus

“…30,34 Furthermore, microencapsulated cells are protected from immune rejection because leukocytes and antibodies cannot penetrate the capsule. 7,13,14 Thus, it becomes an ideal tool for allogeneic and xenogeneic transplantation. The concept of microencapsulation may therefore eliminate the requirement for immune suppressants when used in transplantations.…”

Microencapsulated Stem Cells for Tissue Repairing: Implications in Cell-Based Myocardial Therapy

“…It is most suitable for cell encapsulation as it produces monodisperse beads with a small diameter that prevents diffusion limitations; the narrow size distribution prevents cell necrosis. Figure 3 shows the molecular structure and photomicrographs of microcapsules composed of APA polymer formulation produced by the Inotech Encapsulator [27][28][29]. The APA system employing polyelectrolyte complexation has proven advantageous as its aqueous-based, relatively mild encapsulation conditions do not compromise cell viability.…”