Porous biodegradable polymeric scaffolds prepared by thermally induced phase separation

Abstract

Poly(L-lactic acid) and its copolymers with Dlactic and glycolic acid were used to fabricate various porous biodegradable scaffolds suitable for tissue engineering and drug delivery based on a thermally induced phase separation (TIPS) technique. A variety of parameters involved in TIPS process, such as types of polymers, polymer concentration, solvent/nonsolvent ratio, and quenching temperature, were examined in detail to produce a wide array of micro-and macroporous structures. A mixture of dioxane and water was used for a binary composition of solvent and nonsolvent, respectively. In particular, the coarsening effect of pore enlargement affected by controlling the quenching temperature was used for the generation of a macroporous open cellular structure with pore diameters above 100 m. The use of amorphous polymers with a slow cooling rate resulted in a macroporous open cellular structure, whereas that of semicrystalline polymers with a fast cooling rate generated a microporous closed cellular structure. The fabricated porous devices loaded with recombinant human growth hormone (rhGH) were tested for the controlled delivery of rhGH, as a potential additional means to cell delivery.

Porous Structures: In situ Porous Structures: A Unique Polymer Erosion Mechanism in Biodegradable Dipeptide‐Based Polyphosphazene and Polyester Blends Producing Matrices for Regenerative Engineering (Adv. Funct. Mater. 17/2010)

“…A variety of matrix fabrication techniques including particulate leaching, [28] gas foaming, [29] phase separation, [30] and sphere sintering [31] have been developed to produce 3D porous matrices for skeletal tissue regeneration during the past two decades. It has been demonstrated that a porosity of ~90% is highly desirable for an ideal scaffold by providing sufficient space for extracellular matrix (ECM) synthesis, a high surface area for cell–material interactions, and minimal diffusion constraints.…”

Biomimetic materials for tissue engineering

“…The phase separation of polymer solutions has been explored in our laboratory and others to generate porous structures as tissue engineering scaffolds [11,[82][83][84][85][86][87][88]. When phase separation occurs, a polymer solution separates into two phases, a polymer-rich phase (with a high polymer concentration) and a polymer-lean phase (with a low polymer concentration).…”

Repair of critical size defects in the rat cranium using ceramic‐reinforced PLA scaffolds obtained by supercritical gas foaming

“…An overall rating was obtained using weighting factors (53 for the capsular thickness, 33 for the cellular response observed in the capsule, 53 for the neutrophils, 23 for the FBGCs, 13 for the lymphocytes, 13 for macrophages, and 13 for the fibroblasts). Reactions were classified into 6 categories, which were as follows: no reaction (0), minimal (1-10), slight (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), moderate (26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), marked (41-60), and excessive (>60).…”