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Hydroxyapatite sonosensitization of ultrasound‐triggered, thermally responsive hydrogels: An on‐demand delivery system for bone repair applications
Author(s) -
Levingstone Tanya,
Ali Badriah,
Kearney Cathal,
Dunne Nicholas
Publication year - 2021
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.34820
Subject(s) - self healing hydrogels , regeneration (biology) , therapeutic ultrasound , bone morphogenetic protein 2 , biomedical engineering , bovine serum albumin , bone healing , biophysics , chemistry , ultrasound , materials science , microbiology and biotechnology , anatomy , chromatography , biochemistry , medicine , in vitro , polymer chemistry , biology , radiology
While bones have the innate capability to physiologically regenerate, in certain cases regeneration is suboptimal, too slow, or does not occur. Biomaterials‐based growth factor delivery systems have shown potential for the treatment of challenging bone defects, however, achieving controlled growth factor release remains a challenge. The objective of this study was to develop a thermally responsive hydrogel for bone regeneration capable of ultrasound‐triggered on‐demand delivery of therapeutic agents. Furthermore, it was hypothesized that incorporation of hydroxyapatite (HA) into the hydrogel could increase sonosensitization, augmenting ultrasound sensitivity to enable controlled therapeutic release to the target tissue. Alginate thermally responsive P(Alg‐g‐NIPAAm) hydrogels were fabricated and varying quantities of HA (1, 3, 5, and 7% wt./vol.) incorporated. All hydrogels were highly injectable (maximum injection force below 6.5 N) and rheological characterization demonstrated their ability to gel at body temperature. The study demonstrated the ultrasound‐triggered release of sodium fluorescein (NaF), bovine serum albumin (BSA), and bone morphogenetic protein 2 (BMP‐2) from the hydrogels. Release rates of BSA and BMP‐2 were significantly enhanced in the HA containing hydrogels, confirming for the first time the role of HA as a son sensitizer. Together these results demonstrate the potential of these ultrasound‐triggered thermally responsive hydrogels for on‐demand delivery of therapeutic agents for bone regeneration.