Self-assembled monolayer films of phosphonates for bonding RGD to titanium.
Modification of the implant surface with the Arg-Gly-Asp tripeptide (RGD) putatively facilitates osteoblast attachment for improved implant fixation in the laboratory. We compared the histomorphometric and mechanical performance of titanium implants coated with RGD using a novel interface of self-assembled monolayers of phosphonates (RGD/SAMP) and implants coated with RGD using the more conventional thiolate-gold interface (RGD/thiolate-gold). We hypothesized RGD/SAMP-coated implants would show greater bone ongrowth and implant fixation than RGD/thiolate-gold-coated ones. We implanted an RGD/SAMP-coated implant in one femur and an RGD/thiolate-gold-coated in the contralateral femur of 60 rats. At 2, 4, and 8 weeks after implantation, 10 rats were sacrificed for histologic evaluation and another 10 for biomechanical testing. Bone-implant ongrowth and implant force-to-failure of the two implants were similar at all times. Although RGD/SAMP-coated implants did not show superior bone ongrowth and implant fixation, RGD/SAMP-coated implants have at least equally good histomorphometric and mechanical in vivo performance as RGD/thiolate-gold-coated ones. Additional in vivo characterization of self-assembled monolayer films of phosphonates as interface to bond RGD to titanium is needed to explore its full potential and seems justified based on the results of this study.
Heijink
Andras
A
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, USA. heijink.andras@mayo.edu
Schwartz
Jeffrey
J
Zobitz
Mark E
ME
Nicole Crowder
K
K
Lutz
Gregory E
GE
Sibonga
Jean D
JD
D000497:Alloys; D000818:Animals; D020099:Coated Materials, Biocompatible; D005269:Femur / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006046:Gold / Q000737:chemistry; D020007:Implants, Experimental; D008297:Male; D008422:Materials Testing; D009842:Oligopeptides / Q000737:chemistry*; D063065:Organophosphonates / Q000737:chemistry*; D016348:Osseointegration; D011474:Prosthesis Design; D011475:Prosthesis Failure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D020099:Coated Materials, Biocompatible; D009842:Oligopeptides; D063065:Organophosphonates; D013438:Sulfhydryl Compounds; C031462:titanium alloy (TiAl6V4); D006046:Gold; C047981:arginyl-glycyl-aspartic acid; D014025:Titanium