title: Fabrication of interconnected microporous biomaterials with high hydroxyapatite nanoparticle loading.
abstract: Hydroxyapatite (HA) is known to promote osteogenicity and enhance the mechanical properties of biopolymers. However, incorporating a large amount of HA into a porous biopolymer still remains a challenge. In the present work, a new method was developed to produce interconnected microporous poly(glycolic-co-lactic acid) (PLGA) with high HA nanoparticle loading. First, a ternary blend comprising PLGA/PS (polystyrene)/HA (40/40/20 wt%) was prepared by melt blending under conditions for formation of a co-continuous phase structure. Next, a dynamic annealing stage under small-strain oscillation was applied to the blend to facilitate nanoparticle redistribution. Finally, the PS phase was sacrificially extracted, leaving a porous matrix. The results from different characterizations suggested that the applied small-strain oscillation substantially accelerated the migration of HA nanoparticles during annealing from the PS phase to the PLGA phase; nearly all HA particles were uniformly presented in the PLGA phase after a short period of annealing. After dissolution of the PS phase, a PLGA material with interconnected microporous structure was successfully produced, with a high HA loading above 30 wt%. The mechanisms beneath the experimental observations, particularly on the enhanced particle migration process, were discussed, and strategies for producing highly particle loaded biopolymers with interconnected microporous structures were proposed.
authors.affiliation: School of Polymer Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Donggang
authors.initials: D
authors.lastname: Yao
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jack G
authors.initials: JG
authors.lastname: Zhou
authors.forename: Peter I
authors.initials: PI
authors.lastname: Lelkes
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011137:Polystyrenes / Q000737:chemistry; D016062:Porosity; D019736:Prostheses and Implants
chemical_list: D001672:Biocompatible Materials; D001704:Biopolymers; D011137:Polystyrenes; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D017886:Durapatite