title: Intrafibrillar silicification of collagen scaffolds for sustained release of stem cell homing chemokine in hard tissue regeneration.
abstract: Traditional bone regeneration strategies relied on supplementation of biomaterials constructs with stem or progenitor cells or growth factors. By contrast, cell homing strategies employ chemokines to mobilize stem or progenitor cells from host bone marrow and tissue niches to injured sites. Although silica-based biomaterials exhibit osteogenic and angiogenic potentials, they lack cell homing capability. Stromal cell-derived factor-1 (SDF-1) plays a pivotal role in mobilization and homing of stem cells to injured tissues. In this work, we demonstrated that 3-dimensional collagen scaffolds infiltrated with intrafibrillar silica are biodegradable and highly biocompatible. They exhibit improved compressive stress-strain responses and toughness over nonsilicified collagen scaffolds. They are osteoconductive and up-regulate expressions of osteogenesis- and angiogenesis-related genes more significantly than nonsilicified collagen scaffolds. In addition, these scaffolds reversibly bind SDF-1α for sustained release of this chemokine, which exhibits in vitro cell homing characteristics. When implanted subcutaneously in an in vivo mouse model, SDF-1α-loaded silicified collagen scaffolds stimulate the formation of ectopic bone and blood capillaries within the scaffold and abrogate the need for cell seeding or supplementation of osteogenic and angiogenic growth factors. Intrafibrillar-silicified collagen scaffolds with sustained SDF-1α release represent a less costly and complex alternative to contemporary cell seeding approaches and provide new therapeutic options for in situ hard tissue regeneration.
authors.affiliation: School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Niu
authors.forename: Kai
authors.initials: K
authors.lastname: Jiao
authors.forename: Yi-Pin
authors.initials: YP
authors.lastname: Qi
authors.forename: Sergey
authors.initials: S
authors.lastname: Nikonov
authors.forename: Cynthia K Y
authors.initials: CK
authors.lastname: Yiu
authors.forename: Dwayne D
authors.initials: DD
authors.lastname: Arola
authors.forename: Shi-Qiang
authors.initials: SQ
authors.lastname: Gong
authors.forename: Ahmed
authors.initials: A
authors.lastname: El-Marakby
authors.forename: Marcela R O
authors.initials: MR
authors.lastname: Carrilho
authors.forename: Mark W
authors.initials: MW
authors.lastname: Hamrick
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Hargreaves
authors.forename: Anibal
authors.initials: A
authors.lastname: Diogenes
authors.forename: Ji-Hua
authors.initials: JH
authors.lastname: Chen
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001861:Bone Regeneration; D002470:Cell Survival; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D048091:Guided Tissue Regeneration / Q000379:methods*; D006801:Humans; D008422:Materials Testing; D051379:Mice; D010012:Osteogenesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012824:Silicic Acid / Q000737:chemistry*; D013234:Stem Cells / Q000502:physiology; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D054377:Chemokine CXCL12; D012333:RNA, Messenger; D012824:Silicic Acid; D003094:Collagen