Linking of bone morphogenetic protein-2 to resorbable fracture plates for enhancing bone healing.
OBJECTIVE
To test whether bone morphogenetic protein (BMP)-2 may be covalently linked to resorbable fracture repair plates using an ester-hydrolysis reaction and determining whether the linked compound can facilitate bone growth.


METHODS
Laboratory in vitro experiments.


METHODS
Resorbable fracture repair plates were partially hydrolyzed using varying concentrations of acid or base. This intermediate was then reacted with EDAC (1-ethyl-3[-3-dimethylamino propyl carbodiimide) to form an EDAC intermediate, which was then reacted with either horseradish peroxidase (HRP), interleukin (IL)-2, or BMP-2. Compound binding to the plate was confirmed by immunofluorescent staining. Confirmation of protein function was determined by the following assays: HRP's ability to cleave peroxide, IL-2's ability to stimulate lymphocytes, and BMP-2's ability to stimulate C3H10T1/2 cells to generate alkaline phosphatase.


RESULTS
Three compounds (HRP, IL-2, and BMP-2) were successfully linked to plates as confirmed by immunofluorescence staining or functional testing. Compounds demonstrated better covalent linking to plates under basic conditions. HRP, IL-2, and BMP-2 retained function after binding as measured by cleaved peroxide levels, lymphocytes proliferation, and alkaline phosphatase production.


CONCLUSIONS
Covalent linking of compounds such as HRP, IL-2, and BMP-2 to resorbable plates is possible and represents a novel protein delivery technique. BMP-2 covalently linked to resorbable plates may be used to facilitate bone healing. Covalent linking of compounds to plates represents a novel method for delivering concentrated levels of growth factors to a specific site and potentially extending their half-life. Further investigation into this application for bone healing may lead to quicker healing.
Shibuya
Terry Y
TY
Department of Otolaryngology/Head and Neck Surgery, University of California Irvine School of Medicine, Orange, California 92868, USA. tshibuya@uci.edu
Wadhwa
Ashish
A
Nguyen
Kevin H
KH
Panossian
Abraham M
AM
Kim
Sanghun
S
Wong
Hausin
H
Feinberg
Steven
S
Damisah
Eyiyemisi C
EC
Camilon
P Ryan
PR
Bang
Hoang
H
D020341:Absorbable Implants; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism* / Q000627:therapeutic use; D001860:Bone Plates; D005147:Facial Bones / Q000293:injuries; D017102:Fracture Healing / Q000502:physiology*; D006735:Horseradish Peroxidase / Q000378:metabolism / Q000627:therapeutic use; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism / Q000627:therapeutic use; D012887:Skull Fractures / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D046509:Tissue Culture Techniques; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000627:therapeutic use
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D007376:Interleukin-2; D016212:Transforming Growth Factor beta; D006735:Horseradish Peroxidase