title: Targeted delivery system for juxtacrine signaling growth factor based on rhBMP-2-mediated carrier-protein conjugation.
abstract: We propose a model of artificial juxtacrine signaling for the controlled release of recombinant human bone morphogenetic protein-2 (rhBMP-2) suitable for guided bone regeneration. A porous three-dimensional scaffold of poly-(lactide-co-glycolide) was fabricated by means of gel molding and particulate leaching. Collagen immobilization onto the scaffold surface was produced by performing photo-induced graft polymerization of acrylic acid, and rhBMP-2 was tethered to the collagenous surface by covalent conjugation. On pharmacokinetic analysis, in vitro enzyme-linked immunosorbent and alkaline phosphatase assays revealed sustained, slow release of rhBMP-2 over 28 days, with a cumulative release of one third of the initial load diffusing out of the scaffold. Conjugation of rhBMP-2 inhibited the free lateral diffusion and internalization of the activated complex of rhBMP-2 and the bone morphogenetic protein receptor. Osteoprogenitor cells were used as bone precursors to determine the expression of biosignaling growth factor in regulating cell proliferation and differentiation. To identify the phenotype of cells seeded on the rhBMP-2-conjugated scaffold, cellular activity was evaluated with scanning electron microscopy and with viability, histological, and immunohistochemical testing. The rhBMP-2-conjugated scaffold prolonged stimulation of intracellular signal proteins in cells. Enhancement of cell growth and differentiation was considered a consequence of juxtacrine signaling transduction. Animal studies of rhBMP-2-containing filling implants showed evidence of resorption and de novo bone formation. The present study revealed the potential of biomimetic constructs with co-immobilized adhesion and growth factors to induce osteoinduction and osteogenesis. Such constructs may be useful as synthetic bone-graft materials in orthopaedic tissue engineering.
authors.affiliation: Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang Fu Road, Hsinchu 30013, Taiwan.
authors.forename: Hsia-Wei
authors.initials: HW
authors.lastname: Liu
authors.forename: Chih-Hwa
authors.initials: CH
authors.lastname: Chen
authors.forename: Ching-Lin
authors.initials: CL
authors.lastname: Tsai
authors.forename: Ging-Ho
authors.initials: GH
authors.lastname: Hsiue
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D055396:Bone Morphogenetic Protein 2; D052004:Bone Morphogenetic Protein Receptors / Q000737:chemistry; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D001861:Bone Regeneration / Q000187:drug effects; D018786:Bone Substitutes / Q000737:chemistry; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods*; D004789:Enzyme Activation / Q000187:drug effects; D007150:Immunohistochemistry; D020007:Implants, Experimental; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010012:Osteogenesis / Q000187:drug effects; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D011817:Rabbits; D011994:Recombinant Proteins / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D016212:Transforming Growth Factor beta / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D011108:Polymers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D003094:Collagen; D052004:Bone Morphogenetic Protein Receptors; D000469:Alkaline Phosphatase