Novel biodegradable poly(propylene fumarate)-co-poly(l-lactic acid) porous scaffolds fabricated by phase separation for tissue engineering applications

Abstract

Scaffolds with intrinsically interconnected porous structures are highly desirable in tissue engineering and regenerative medicine. In this study, three-dimensional polymer scaffolds with highly interconnected porous structures were fabricated by thermally induced phase separation of novel synthesized biodegradable poly(propylene fumarate)-co-poly(l-lactic acid) in a dioxane/water binary system. Defined porous scaffolds were achieved by optimizing conditions to attain interconnected porous structures. The effect of phase separation parameters on scaffold morphology were investigated, including polymer concentration (1, 3, 5, 7, and 9%), quench time (1, 4, and 8 min), dioxane/water ratio (83/17, 85/15, and 87/13 wt/wt), and freeze temperature (−20, −80, and −196 °C). Interesting pore morphologies were created by adjusting these processing parameters, e.g., flower-shaped (5%; 85/15; 1 min; −80 °C), spherulite-like (5%; 85/15; 8 min; −80 °C), and bead-like (5%; 87/13; 1 min; −80 °C) morphology. Modulation of phase separation conditions also resulted in remarkable differences in scaffold porosities (81% to 91%) and thermal properties. Furthermore, scaffolds with varied mechanic strengths, degradation rates, and protein adsorption capabilities could be fabricated using the phase separation method. In summary, this work provides an effective route to generate multi-dimensional porous scaffolds that can be applied to a variety of hydrophobic polymers and copolymers. The generated scaffolds could potentially be useful for various tissue engineering applications including bone tissue engineering.

Tunable tissue scaffolds fabricated by in situ crosslink in phase separation system

“…The cloud-point was determined at the temperature when clear solutions became turbid and gelation temperatures were determined when solutions ceased to flow after the vials were inverted horizontally, as described in previous studies. 27,29 In this study, the cloud and gelation point values are close to but slightly higher (Fig. 1C) than those reported in our previous study which used PPF- co -PLLA copolymers from different batches.…”

“…28 Dried PPF terminated with hydroxyl groups were then copolymerized with L-lactide monomer at 140 °C for 24 hours using stannous octoate (Sn(Oct) 2 ) as catalyst, as reported in our previous study. 27 The hydroxyl groups in PPF initiate the ring opening polymerization of L-lactide monomer. Further chain propagation resulted in a PLLA-b-PPF-b-PLLA triblock copolymer, which will be referred to as PPF- co -PLLA copolymer in this study.…”

“…1C) than those reported in our previous study which used PPF- co -PLLA copolymers from different batches. 27 Vials with dissolved PPF- co -PLLA were then cooled down at room temperature until clouding was observed, which indicates phase separation had occurred. Next, the samples were immediately transferred for UV irradiation (Black-Ray Model 100AP, Upland, CA) for 30 min to photocrosslink the polymer chains.…”

Cross‐linkable graphene oxide embedded nanocomposite hydrogel with enhanced mechanics and cytocompatibility for tissue engineering

“…Depending on the specific tissue engineering application, the polymers applied can be varied. [55][56][57][58][59] CONCLUSIONS Graphene oxide Tris acrylate was successfully synthesized and applied toward hydrogel formation by chemical crosslinking with acrylamide (GO-TrisA/PAM). (A) Sterilized rGO 10 PAM 1000 and (B) rGO-TrisA 10 PAM 1000 nanocomposite hydrogel before and after incubation in aqueous solution for 2 weeks at 808C.…”

Novel porous poly(propylene fumarate‐co‐caprolactone) scaffolds fabricated by thermally induced phase separation

“…The cloud point temperatures of the P(PF-co-CL)21,4-dioxane-water ternary system were estimated by visual turbidimetry. 27 Certain amounts of P(PF-co-CL) (2,4,6,8,10,12, and 14 wt %) were fully dissolved in a dioxane-water mixture (76/24 wt/wt) by water bath at 808C for 2 h. Then the clear mixture was slowly cooled at a rate of 18C/min, and the cloud point temperatures were recorded. (Cloud point was the temperature at which the mixture became turbid.)…”