Pluronic F127 as a Cell Encapsulation Material: Utilization of Membrane-Stabilizing Agents

Abstract

Thermoreversible gelation of the copolymer Pluronic F127 (generic name, poloxamer 407) in water makes it a unique candidate for cell encapsulation applications, either alone or to promote cell seeding and attachment in tissue scaffolds. At concentrations of 15-20% (w/w), aqueous Pluronic F127 (F127) solutions gel at physiological temperatures. The effect of F127 on viability and proliferation of human liver carcinoma cells (HepG2) was determined for both liquid and gel formulations. Cell concentration and viability over a 5-day period were measured by the trypan blue assay via hemocytometry and results were confirmed in both the MTT and LDH assays. With 0.1-5% (w/w) F127 (liquid), cells proliferated and maintained high viability over 5 days. However, at 10% (w/w) F127 (liquid), there was a significant decrease in cell viability and no cell proliferation was evident. HepG2 cell encapsulation in F127 concentrations ranging from 15 to 20% (w/w) (gel) resulted in complete cell death by 5 days. This was also true for the HMEC-1 (endothelial) and L6 (muscle) cell lines evaluated. Cell-seeding density did not affect cell survival or proliferation. Membrane-stabilizing agents (hydrocortisone, glucose, and glycerol) were added to the F127 gel formulations to improve cell viability. The steroid hydrocortisone demonstrated the most significant improvement in viability, from <2% (in F127 alone) to >70% (with 60 nM hydrocortisone added). These results suggest that F127 formulations supplemented with membrane-stabilizing agents can serve as viable cell encapsulation materials. In addition, hydrocortisone may be generally useful in the promotion of cell viability for a wide range of encapsulation materials.

3D Bioprinting Using a Templated Porous Bioink

“…Previous studies have shown cytotoxic effects when F127 is used as an encapsulating gel (60%-70% viability for 15.6 wt% F127), but not when used as a liquid additive (80%-90% viability for 10 wt% F127), with more severe effects at higher weight percentage and longer exposure time (quoted fi gures for HepG2 cells, t = 1 d). [ 32 ] These values correlate well with the results from our study, where hMSCs are only exposed to 13 wt% F127 during mixing and printing (typically 30-60 min), before F127 is expelled from the hybrid gel. In general, hMSCs encapsulated within the hybrid gel adopted a spherical cell morphology, an equilibrium geometry assumed in the absence of microscale features or integrin binding sites, and typical of nanofi brous gels, such as alginate.…”

Fabricating scaffolds by microfluidics

“…It has been shown that cells proliferate and maintain high viability at this concentration of Pluronic ® F127. 27 The alginate solution was injected at a controlled flow rate by a syringe pump ͑Ph.D 22/2000, Harvard Apparatus, USA͒. The pressure was measured by a digital pressure indicator ͑PM, Heise, USA͒.…”

Interaction Forces between Supported Lipid Bilayers in the Presence of PEGylated Polymers

“…This commercially available family of polymers, some of which are approved for medical use by the FDA, has been tested in many biomedical studies. The most commonly tested Pluronics include Pluronic F68, which has been shown to be a very potent suppressor of carcinogenesis in the colon of rats and mice, 8 Pluronic F127, which demonstrated the ability to penetrate cellular membranes and to stabilize them after being subjected to an external stress, 9 and Pluronic P85, which has been shown to significantly enhance drug permeability through epithelial cells. 10 Due to the many beneficial biological and biomedical properties of Pluronics that have been reported to date, we decided to characterize the interactions forces between Pluronics and lipid membranes using a surface forces apparatus (SFA) to provide a molecular level understanding of the interaction forces that may be at the origin of these reported properties.…”