Honeycomb Films of Biodegradable Polymers for Tissue Engineering

Abstract

We report that microporous films (honeycomb films) can lead various types of cells to tissue formation. The honeycomb films were fabricated by applying a moist air to a spread polymer solution containing biodegradable polymers (poly(L-lactic acid) (PLLA) and poly (ε-caprolactone) (PCL)) and an amphiphilic polymer. Hepatocytes were cultured on a self-supporting honeycomb film of PLLA. The hepatocytes formed a single layer of columnar shape cells with a thickness of 20 μm. The tissue formation of hepatocytes specifically occurred on the honeycomb film of PLLA, not on a flat film of PLLA. Three dimensional tissue structures were formed, when cells were cultured on both sides of the self-supporting honeycomb film. Double layers of hepatocytes were obtained by the method. Striated tissues such as heart and blood vessel could be reconstructed by utilizing a stretched honeycomb film of PCL.

Influence of Solvents on the Formation of Honeycomb Films by Water Droplets Templating

“…It must be pointed out that we fabricated honeycomb patterns in a static humid atmosphere, which had some difference from the dynamic moist environment reported in other references. [6,14] The formation of honeycomb film in flowing humid air was performed as follows: carrier nitrogen gas was bubbled through distilled water and then sent with water vapor onto the solution surface. By this method the evaporation rate of the solvent could be accelerated.…”

“…The formation of honeycomb structures in high humidity, first reported by François et al, [1] has received great interest in recent years due to their potential applications in chemical sensors, [2] optical apparatus, [3] scaffold for catalysis, [4] biology, [5] tissue engineering, [6] and micrographics . [7] François et al cast the solution of poly(paraphenylene) in carbon disulfide (CS 2 ) onto a substrate in a highly humid atmosphere.…”

Formation of honeycomb films from poly(L‐lactide)‐block‐poly(ethylene glycol) via water‐droplet templating

“…The formation of honeycomb films in high humidity was one of the great developments in the field of molecular self‐assembly,1 and was first described by François and co‐workers 2–4. They can be applied in chemical sensors,5 scaffolds for catalysis,6 biology,7 tissue engineering,8 etc. The process of forming the honeycomb films was described as follows: (1) water droplets were condensed on the surface of the solution due to cooling by solvent evaporation; (2) because of the incompatibility of the organic solvent and water, as well as the hydrophilic/hydrophobic balance of the polymer solution, water droplets were closely packed on the surface of the solution; and (3) after the water and the solvent evaporated completely, honeycomb films were prepared.…”

“…However, PLA cannot form honeycomb films via water‐droplet templating. Only by adding a few additives in its solution8 or copolymerizing its units with other monomers16, 17 can honeycomb films be formed. Poly( L ‐lactide)‐ block ‐poly(ethylene glycol) (PLEG) is an excellent biodegradable polymer, and is known for both its biocompatibility and ability to be reabsorbed through natural pathways.…”

Formation of honeycomb films based on a soluble polyimide synthesized from 2,2′‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride and 3,3′‐dimethyl‐4,4′‐diaminodiphenylmethane

“…Porous polymer films with a perfect arrangement provide interesting properties for various potential applications. They can be used, for example, as filters in separation,1 as building materials in tissue engineering,2 and as scaffolds in catalysis 3. Among those methods used for preparing micropatterned surfaces, the casting of polymer solutions under high humidity, as pioneered by François et al,4 has been famous in recent years.…”