Clinical-grade titanium implants were grafted with a non-fouling oligo(ethylene glycol)-substituted polymer coating functionalized with equimolar densities of either RGD peptide or greek small letter alpha5β1-integrin-specific FN fragment FNIII7-10. Biomaterials presenting FNIII7-10 supported enhanced greek small letter alpha5β1 integrin binding and osteoblastic differentiation in bone marrow stromal cells compared to unmodified titanium and RGD-presenting surfaces, which promoted primarily greek small letter alphavβ3 binding. Importantly, FNIII7-10-functionalized titanium significantly improved functional implant osseointegration compared to RGD-functionalized and unmodified titanium in vivo. This work identifies a robust strategy that may be applicable to improve the biological performance of other biomedical devices and constructs for regenerative medicine.
I hear things about "functionalized" very often now. It is extremely interesting, not only in the nano-technology field, but also in medicine. This paper is just an example of these biomaterials.
Biomaterials. 2008 Jul;29(19):2849-57.
The effect of integrin-specific bioactive coatings on tissue healing and implant osseointegration.
Petrie TA, Raynor JE, Reyes CD, Burns KL, Collard DM, García AJ.Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Implant osseointegration, defined as bone apposition and functional fixation, is a requisite for clinical success in orthopaedic and dental applications, many of which are restricted by implant loosening. Modification of implants to present bioactive motifs such as the RGD cell-adhesive sequence from fibronectin (FN) represents a promising approach in regenerative medicine. However, these biomimetic strategies have yielded only marginal enhancements in tissue healing in vivo. In this study, clinical-grade titanium implants were grafted with a non-fouling oligo(ethylene glycol)-substituted polymer coating functionalized with controlled densities of ligands of varying specificity for target integrin receptors. Biomaterials presenting the alpha(5)beta(1)-integrin-specific FN fragment FNIII(7-10) enhanced osteoblastic differentiation in bone marrow stromal cells compared to unmodified titanium and RGD-presenting surfaces. Importantly, FNIII(7-10)-functionalized titanium significantly improved functional implant osseointegration compared to RGD-functionalized and unmodified titanium in vivo. This study demonstrates that bioactive coatings that promote integrin binding specificity regulate marrow-derived progenitor osteoblastic differentiation and enhance healing responses and functional integration of biomedical implants. This work identifies an innovative strategy for the rational design of biomaterials for regenerative medicine.
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