Modulating the release of proteins from a loaded carrier of alginate/gelatin porous spheres immersed in different solutions.

Background: A biodegradable porous particle for the controlled biofactor delivery which assembly of pores in scaffolds can improve the permeation and diffusion of drugs or growth factors.

Objective: Porous-spheres in millimeter scale were prepared by mixing sodium alginate and gelatin interpenetrating networks with cross-linkers; interconnected open pores were fabricated through solvent casting and particulate leaching.

Methods: Morphological characteristics, degradation, and bovine serum albumin (BSA) release rates of the porous-spheres immersed in three different solutions, namely, deionized distilled water, simulated body fluid (SBF), and phosphate-buffered saline (PBS), were detected.

Results: Porous-spheres with a large amount of gelatin exhibited an increase in water absorption rates without affecting scaffold strength and no cytotoxicity was elicited. Highly interconnected pores with a diameter of 100-200 µm were uniformly distributed in scaffolds. The weight loss in PBS was faster than that in other solutions; the highest release rate of BSA in SBF was observed for 2 h. The release rates also exhibited linear patterns from 2 h to 24 h in all of the groups.

Conclusions: After 1 d of immersion in solutions, BSA release rates in scaffolds logarithmically decreased for 14 d. The degradation of porous-spheres also showed an inverse pattern.