Nano-scale characterization of nano-hydroxyapatite incorporated chitosan particles for bone repair

• Published in: Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2018-05, Vol.165, p.158-164
• Main Authors: Gaihre, Bipin, Uswatta, Suren, Jayasuriya, Ambalangodage C.
• Format: Article
• Language: English
• Subjects: adhesion; Atomic force microscopy; biopolymers; Bone Morphogenetic Protein 2 - pharmacology; Bone morphogenetic protein-2; Bone Regeneration - drug effects; Chitosan; Chitosan - chemistry; colloids; deformation; droplets; Durapatite - chemistry; energy; Imaging, Three-Dimensional; Microscopy, Atomic Force; Nano-hydroxyapatite; Nanocomposites - chemistry; Particles; sodium tripolyphosphate; Topography
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2018.02.034

[Display omitted] •Surface of both types of particles was rough with many nano peaks and pores.•Adhesion force was higher along the deeper region compared to superficial regions.•Deformation of the particle surface was mostly uniform for both particle groups.•About 87% of BMP-2 encapsulated in the particles was released by third week. In this study, injectable porous spherical particles were fabricated using chitosan (CS) biopolymer, sodium tripolyphosphate (TPP), and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink 2% (w/v) CS droplets. 2% (w/v) nHA was used to prepare nHA incorporated particles. The surface morphological properties and nanomechanical properties such as topography, deformation, adhesion, and dissipation of CS particles with and without nHA were studied using contact mode and peakforce quantitative nanomechanical property mapping mode in atomic force microscopy. The nHA spots have higher density than CS which leads to higher forces acting on the probe tip and higher energy dissipation to lift the tip from nHA areas. The cumulative release data showed that about 87% of total BMP-2 encapsulated within the particles was released by third week of experiment period. Degradation study was conducted to understand how the particles degradation occurs in the presence of phosphate buffered saline with continues shaking in an incubator at 37° C. In addition, BMP-2 release from the 2% nHA/CS particles was studied over a three weeks period and found that BMP-2 release was governed by the simple diffusion rather than the degradation of particles.