title: Delivery of demineralized bone matrix powder using a thermogelling chitosan carrier.
abstract: Demineralized bone matrix (DBM) powder is widely used for bone regeneration due to its osteoinductivity and osteoconductivity. However, difficulties with handling, its tendency to migrate from graft sites, and lack of stability after surgery can sometimes limit the clinical utility of this material. In this work, the possibility of using a thermogelling chitosan carrier to deliver DBM powder was assessed. The DBM-thermogelling putty improved handling and formed a gel-like composite in situ at body temperature within a clinically relevant time period. The properties of the formed composite, including morphology, porosity, mechanical properties, equilibrium swelling as well as degradability, are significantly influenced by the ratio of DBM to thermogelling chitosan. The in vitro study showed that the alkaline phosphatase activity of C2C12 cells encapsulated in the composite was steadily increased with culture time. The in vivo study showed that increased DBM content in the DBM-thermogelling chitosan induced ectopic bone formation in a nude rat model. The diffusion of growth factor from the DBM-thermogelling chitosan as well as the host-implant interactions are discussed.
authors.affiliation: Department of Biomedical Engineering, College of Polymer Science & Engineering, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Tian
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Kenrick
authors.initials: K
authors.lastname: Kuwahara
authors.forename: Marcel E
authors.initials: ME
authors.lastname: Nimni
authors.forename: Changxiu
authors.initials: C
authors.lastname: Wan
authors.forename: Bo
authors.initials: B
authors.lastname: Han
mesh_terms: D000818:Animals; D018775:Bone Demineralization Technique; D001857:Bone Matrix / Q000737:chemistry* / Q000648:ultrastructure; D049109:Cell Proliferation; D002478:Cells, Cultured; D048271:Chitosan / Q000737:chemistry*; D017364:Collagenases / Q000378:metabolism; D019245:Compressive Strength; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods*; D005782:Gels; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D020007:Implants, Experimental; D051379:Mice; D008856:Microscopy, Fluorescence; D009113:Muramidase / Q000378:metabolism; D011208:Powders; D051381:Rats; D011923:Rats, Nude; D013696:Temperature
chemical_list: D004337:Drug Carriers; D005782:Gels; D011208:Powders; D049452:Green Fluorescent Proteins; D048271:Chitosan; D009113:Muramidase; D017364:Collagenases