Biocompatibility and in vivo evaluation of oligochitosans as cationic modifiers of alginate/Ca microcapsules

Abstract

The present article investigates the substitution of poly-L-lysine by two different oligochitosans as membrane-coating capsule, and its effect on different functionality parameters of cell microencapsulation. To address this issue, initially the biocompatibility of the two types of oligochitosan solutions was evaluated using erythropoietin secreting C2C12 myoblast cell line as model. In a second step, we encapsulated the cells within alginate microcapsules coated with each oligochitosan and a complete morphological and mechanical evaluation was performed. Finally, the in vivo functionality of the enclosed cells in the alginate-oligochitosan microcapsules was studied in Balb/c mice. Results show that both oligochitosans were biocompatible, not detecting statistical differences between them. The alginate-oligochitosan microcapsules were totally spherical and uniform and resulted in high hematocrit levels after subcutaneous implantation in mice. In fact, significantly higher hematocrit levels were found in the animals transplanted with the encapsulated cells compared with the control group. Finally, the histological analysis showed a mild fibroblastic reaction around the capsule membrane. These results suggest that alginate-oligochitosan capsules may be an interesting alternative to conventional alginate- poly-L-lysine capsules.

Safety and efficacy of hydroxyapatite scaffold in the prevention of jaw osteonecrosis in vivo

“…In respect to hepatic function in T1 group, a promising result was found when evaluating safety in the use of new biomaterials, since the groups that received ZA + insertion of both scaffolds had their AST and ALT activities similar to the control. This finding corroborates the fact that the chitosan/sodium alginate/hydroxyapatite mixture is biocompatible and does not present hepatic toxicity . Elevated serum levels of AST and ALT are found in hepatic injury, signaling the rupture of hepatocytes with extravasation of transaminases to the circulation .…”

Microencapsulating and Banking Living Cells for Cell‐Based Medicine

“…This prolonged exposure of mammalian cells to the low pH results in low cell viability after coating. In addition, the swelling and breaking of alginate-chitosan-alginate (ACA) microcapsules are difficult to overcome when liquefying the alginate core using sodium citrate solution [19, 36, 37]. Moreover, long-term biocompatibility of chitosan and other polycations in vivo needs to be further evaluated rigorously.…”

Biomaterials in Cell Microencapsulation

“…106,107 Recently, modified oligochitosans (quaternary ammonium derivative oligochitosans) have been proposed as an interesting possible alternative to the currently PLL. 108 Results obtained both in vitro and in vivo demonstrated that modified oligochitosans are biocompatible and allow the elaboration of microcapsules mechanically stable at physiological pH.…”