Poly(vinyl alcohol) synthetic polymer foams as scaffolds for cell encapsulation

Abstract

Poly(vinyl alcohol) (PVA) foams were used as scaffolds in hollow fiber membrane-based cell encapsulation devices. The surrounding permselective membrane serves as an immunoisolation barrier while allowing metabolites and other small molecules to be freely transported. The internal matrix defines the microenvironment for the encapsulated cells. PC12 cell-containing devices represent one possible strategy for safe transplantation of dopamine-secreting cells for the treatment of dopamine-deficient diseases such as Parkinson's disease. PC12 cells--a dopamine-secreting cell line--were encapsulated with PVA foam as a matrix material in the lumen of these hollow fibers. In this work, we demonstrate the presence of the PVA matrix increased the catecholamine secretion efficiency of the cells as compared to devices containing a chitosan matrix. Devices were implanted in vivo into rodent striatum and device output of catecholamines was measured preimplant and post-explant. Evoked stores of dopamine remained constant (preimplant vs explant) for devices encapsulated with the foam matrix and increased with devices encapsulated with chitosan matrix. Cell proliferation within devices was inhibited in the presence of the foam matrix. Cell viability and distribution was significantly improved with the inclusion of the foam matrix in both in vitro and in vivo studies. In comparison to chitosan--a typical matrix material for PC12 cells--addition of a foam-type matrix altered the encapsulated cell microenvironment and resulted in more efficient secretion of catecholamines and improved distribution within the device resulting in smaller necrotic regions and a lower rate of cell proliferation.

In vivo calcium deposition on polyvinyl alcohol matrix used in hollow fiber cell macroencapsulation devices

“…As already reported in previous studies, the presence of a matrix for the three-dimensional layout of the cells was shown to significantly preserve cell survival [8,22,26]. A significant difference in cell survival was however observed between the two types of PVA tested despite a similarity in their structure.…”

“…They have some advantages over the naturally derived hydrogels, including an improved intracapsular nutrient transfer through porous interconnecting channels or a control of cell cluster size to a maximum of the foam pore size. Such a scaffold was reported to efficiently support encapsulated PC-12 cells implanted in rodent striatum [26]. Some of these biomaterials were shown, however, to develop calcifications in vivo that can dramatically compromise their function, as previously described for heart and vascular bioprostheses.…”

“…To simulate natural extracellular matrix, hydrogels and hydrocolloid-based encapsulation matrices such as collagens, alginate or chitosan were used to enclose hepatocytes [19], bovine chromaffin cells [6] or PC-12 rat pheochromocytoma cells [44], respectively. Synthetic scaffolds based on polyvinyl alcohol (PVA) foam have also been introduced as a matrix for encapsulated cell devices [26]. They have some advantages over the naturally derived hydrogels, including an improved intracapsular nutrient transfer through porous interconnecting channels or a control of cell cluster size to a maximum of the foam pore size.…”

Polyvinyl alcohol‐poly(caprolactone) Semi IPN scaffold with implication for cartilage tissue engineering

“…PVA is itself biocompatible and any residual polymer should not induce an inflammatory response 30, 31. PVA is approved by FDA (USA) and regulatory organizations in many countries and widely used as a coating material for other polymers or as a supporting material in cell culture 32, 33. Numerous reports have described the use of hydrogels in controlled release formulations.…”

Viability and Functionality of Bovine Chromaffin Cells Encapsulated into Alginate-PLL Microcapsules with a Liquefied Inner Core

“…Microcarable and functional encapsulated BCC. The permeability of the microcapsule membrane permitted nutrient influx riers (3,39), PVA (26) exhibited a good viability and sustained catecholamine transplants containing adrenal chromaffin cells encapsulated or not. Preclinical (22,49) and clinical (4,5) studies secretion.…”