Novel Self-Assembly-Induced Gelation for Nanofibrous Collagen/Hydroxyapatite Composite Microspheres

• Main Authors: Jae-Won Choi, Jong-Woo Kim, In-Hwan Jo, Young-Hag Koh, Hyoun-Ee Kim
• Format: Article
• Language: English
• Published: MDPI AG 2017-09-01
• Series: Materials
• Subjects: biomaterials; porous scaffolds; collagen; hydroxyapatite; in vitro bioactivity
• Online Access: https://www.mdpi.com/1996-1944/10/10/1110

This study demonstrates the utility of the newly developed self-assembly-induced gelation technique for the synthesis of porous collagen/hydroxyapatite (HA) composite microspheres with a nanofibrous structure. This new approach can produce microspheres of a uniform size using the droplets that form at the nozzle tip before gelation. These microspheres can have a highly nanofibrous structure due to the immersion of the droplets in a coagulation bath (water/acetone), in which the collagen aggregates in the solution can self-assemble into fibrils due to pH-dependent precipitation. Bioactive HA particles were incorporated into the collagen solutions, in order to enhance the bioactivity of the composite microspheres. The composite microspheres exhibited a well-defined spherical morphology and a uniform size for all levels of HA content (0 wt %, 10 wt %, 15 wt %, and 20 wt %). Collagen nanofibers—several tens of nanometers in size—were uniformly present throughout the microspheres and the HA particles were also well dispersed. The in vitro apatite-forming ability, assessed using the simulated body fluid (SBF) solution, increased significantly with the incorporation of HA into the composite microspheres.