Degradation behaviors of biodegradable macroporous scaffolds prepared by gas foaming of effervescent salts

Abstract

Biodegradable polymeric scaffolds for tissue engineering were fabricated by a gas-foaming/salt-leaching method using a combination of two effervescent salts, ammonium bicarbonate and citric acid. Poly(D,L-lactic-co-glycolic acid) (PLGA) in a state of gel-like paste was first produced by precipitation of PLGA dissolved in chloroform into ethanol. The polymer slurry was mixed with sieved particles of ammonium bicarbonate, molded, and then immersed in an aqueous solution of citric acid to generate macroporous scaffolds. The scaffolds had relatively homogeneous pore structures throughout the matrix and showed an average pore size of 200 microm and over 90% porosity. By adjusting the concentration of citric acid in the aqueous medium, it was possible to control porosity as well as mechanical strength of the scaffolds. In vitro degradation studies of three different scaffolds having lactic/glycolic acid molar ratios of 75/25, 65/35, and 50/50 exhibited marked swelling behaviors at different critical time points. The swollen matrices had a hydrogel-like internal structure. It was found that massive water uptake into the degrading scaffolds induced matrix swelling, which facilitated the hydrolytic scission of PLGA chains with concomitant disintegration of the matrices.

Intramuscular delivery of DNA releasing microspheres: Microsphere properties and transgene expression

“…Polymer degradation generally decreases the hydrophobicity [41], thus the faster degrading polymers would be less likely to aggregate. PLG with a molecular weight between 80 and 97 kDa, similar to the high MW PLG, had a 3% to 15% mass loss after 12 weeks [42,43]. However, polymers with low MW (8 kDa) exhibited a 78.5% decrease in molecular weight after only 14 days in vitro [44].…”

Preparation of interconnected poly(ε-caprolactone) porous scaffolds by a combination of polymer and salt particulate leaching

“…It was carried out by dissolving a gas at elevated pressure (physical blowing agent) [11][12][13] or by incorporated a chemical that yields gaseous decomposition products (chemical blowing agent) [14][15][16]. The foaming technique generally leads to pore structures that are not as fully interconnected as the previously mentioned ones.…”

Scaffold Materials Based on Fluorocarbon Composites Modified with RF Magnetron Sputtering

“…Then pressure is discharge to form thermodynamic instability of dissolved CO 2 that leads to nucleation and growth of gas vesicles, created pores within polymer matrix. Yoon J.J et al used this method to create high-porous PLGA sponges (Yoon & Park, 2001). Solid PLGA disks, prepared by compressing casting or solution casting, were saturated with CO 2 under high pressure, then pressure was discharged and formed macroporous structure.…”