Preparation of highly interconnected porous poly(ε‐caprolactone)/poly(lactic acid) scaffolds via supercritical foaming

Abstract

Highly interconnected porous polymer scaffolds were prepared by gas foaming.Poly(ε-caprolactone)/poly(lactic acid) blends were melt mixed and batch foamed using CO 2 as a physical blowing agent. The effects of the foaming temperature, pressure, and CO 2 saturation time on the foam morphology were related to the mechanical properties of the scaffolds. The cell size in cross section of scaffolds decreased and became more homogeneous until CO 2 saturation time reached 1.5 hours. With an increase in temperature, the cell size increased markedly and the cell size uniformity decreased gradually, whereas the reverse happened when the foaming pressure was increased. Meanwhile, many open cells can also be detected on the surface of scaffolds. High porosity and an open-cell content of greater than 90% were obtained. The compressive strength of scaffolds was regulated by controlling the foam architecture. The information gathered in this study may provide a theoretical basis for research into porous tissue engineering scaffolds. KEYWORDS batch foaming, mechanical properties, poly(ε-caprolactone)/poly(lactic acid), pore morphology, scaffold

Fabrication of fibrillated and interconnected porous poly(ε-caprolactone) vascular tissue engineering scaffolds by microcellular foaming and polymer leaching

“…Many synthetic thermoplastic aliphatic polymers, such as polylactide (PLA), polyglycolide (PGA), poly(3-caprolactone) (PCL), and poly(lactide-co-glycolide) (PLGA), have been commonly used to fabricate tissue engineering scaffolds because of their excellent biodegradability and biocompatibility. [18][19][20] PCL, a semi-crystalline polymer, has been a popular biomedical material for tissue engineering. PCL has good mechanical properties such as high exibility and elongation.…”

Simple and feasible strategy to fabricate microcellular poly(butylene succinate) foams by chain extension and isothermal crystallization induction

“…The cell density, N , in cells cm −3 , the number of cells per cubic centimeter of various PBS foams, was determined from the following equation: where n is the number of cells in the micrograph, A is the area of the micrograph (in cm 2 ), M is the magnification factor, and the volume expansion ratio (VER) was the volume expansion ratio of various PBS foams, which could be calculated by the following equation: where ρ p and ρ f were the bulk densities of unfoamed and foaming PBS samples in g cm −3 , respectively.…”

“…Compared with numerous disadvantages (chemical residues, production of noxious gases, etc.) in chemical foaming process, physical foaming process had many advantages, such as lower cost, no residues, and less materials usage . Especially, microcellular foaming technology with supercritical CO 2 (sc‐CO 2 ) is a fully green approach and has caught considerable interest of engineers due to its chemically inert, nontoxic, nonflammability, environmentally friendly, relatively mild critical point (31.1 °C and 7.38 MPa), and big solubility in polymers …”

Solvent-Free Approaches for the Processing of Scaffolds in Regenerative Medicine

“…An increase in temperature provides both a reduction in CO 2 density and an increase in diffusivity; consequently, fewer nucleation sites are obtained for scaffolds processed at higher temperatures. In addition, the thermal effect facilitates the chain mobility of the polymer, reducing its viscosity and allowing the pores to grow easier, as well as promoting the pore coalescence phenomena [111,112] (Figure 9a-c). Finally, the soaking time mainly affects the CO 2 distribution along the polymer, resulting in heterogeneous structures when the soaking time is insufficient to achieve a saturation state [111].…”

“…Finally, the soaking time mainly affects the CO 2 distribution along the polymer, resulting in heterogeneous structures when the soaking time is insufficient to achieve a saturation state [111]. Namely, the increase in the soaking time allows a greater gas dissolution in the polymer, which means more nucleation points that upon the release of pressure would render scaffolds with higher cell densities and reduced pore diameters (Figure 9d-f) [112].…”