Establishment of a pulmonary epithelial barrier on biodegradable poly-L-lactic-acid membranes

Abstract

Development of biocompatible and functional scaffolds for tissue engineering is a major challenge, especially for development of polarised epithelia that are critical structures in tissue homeostasis. Different in vitro models of the lung epithelial barrier have been characterized using non-degradable polyethylene terephthalate membranes which limits their uses for tissue engineering. Although poly-L-lactic acid (PLLA) membranes are biodegradable, those prepared via conventional Diffusion Induced Phase Separation (DIPS) lack open-porous geometry and show limited permeability compromising their use for epithelial barrier studies. Here we used PLLA membranes prepared via a modification of the standard DIPS protocol to control the membrane surface morphology and permeability. These were bonded to cell culture inserts for use in barrier function studies. Pulmonary epithelial cells (H441) readily attached to the PLLA membranes and formed a confluent cell layer within two days. This was accompanied by a significant increase in trans-epithelial electrical resistance and correlated with the formation of tight junctions and vectorial cytokine secretion in response to TNFα. Our data suggest that a structurally polarized and functional epithelial barrier can be established on PLLA membranes produced via a non-standard DIPS protocol. Therefore, PLLA membranes have potential utility in lung tissue engineering applications requiring bio-absorbable membranes.

Biodegradable synthetic polymers in biomedical application: A review

“…According to Zeng et al [51], hybrid silk-based scaffolds reinforced with porous PLLA microspheres with a multi-hierarchical porous structure showed good performance in promoting chondrogenesis for auricular cartilage regeneration, being considered promising in areas related to plastic surgery. In turn, PLLA membranes obtained by the modified diffusion-Brazilian Journal of Health Review, Curitiba, v. 5, n. 6, p. 24628-24644, nov./dec., 2022 induced phase separation method, which controls the surface morphology and membrane permeability, responded to the pro-inflammatory stimulus, showing a promising potential for application in lung tissue engineering [52]. Regarding the results obtained by Babilotte et al…”

Poly-l-Lactic Acid (PLLA)-Based Biomaterials for Regenerative Medicine: A Review on Processing and Applications

“…Their research showed that the produced scaffolds with the largest pore size induced a higher proliferation of human mesenchymal stem cells (hMCSs). La Carrubba et al [ 83 , 88 , 91 , 126 , 127 ] have extensively studied PLLA scaffolds produced via phase separation techniques. While investigating both TIPS and DIPS approaches, they optimized operating parameters to obtain porous matrices with different porosities and pore sizes, adequate to host various types of cells.…”

Solution-Based Processing for Scaffold Fabrication in Tissue Engineering Applications: A Brief Review

“…They reported that structures fabricated using a combination of DIPS technique and WNM, which is a mold assembly method using a wire-cutting process, might be more advantageous compared to the conventionally manufactured DIPS structures due to a lower degree of scaffold collapsing during the fabrication process and higher number of attached Saos-2 cells [ 60 ]. Montesanto et al [ 64 ] investigated the structural properties of PLLA membranes fabricated with a modified DIPS process, including the sequential immersion into two coagulation baths, and evaluated the formation of a functional lung epithelial barrier after 5 days of the NCl-H441 cells’ culture on the produced scaffolds. The results showed that the PLLA scaffolds examined had higher porosity and permeability compared to PLLA membranes produced using standard DIPS, hence enhancing epithelial cell function.…”