Adsorption of Tripeptide RGD on Rutile TiO2 Nanotopography Surface in Aqueous Solution

Precision Engineering Research Institute, Harbin Institute of Technology, Harbin 150001, China; Received 28 February 2009. Revised 12 July 2009. Accepted 20 July 2009. Available online 28 July 2009.
Acta Biomaterialia (Impact Factor: 5.68). 02/2010; 6(2):684-694.

ABSTRACT Molecular dynamics simulations were carried out to investigate the adsorption mechanisms of tripeptide Arg-Gly-Asp (RGD) on the nanotopography and perfect rutile TiO2 (1 1 0) surfaces in aqueous solution. It is shown that the amino groups (NH2 and NH3þ) and carboxyl group (COO�) of RGD are the main groups bonding to hydrophilic TiO2 surface by electrostatic and van der Waals interactions. It is also demonstrated
that RGD adsorbs much more rapidly and stably on the nanotopography surface than the perfect surface. On the hydrophilic TiO2 surface, the water molecules occupy the adsorption sites to form hydration layers, which have a significant influence on RGD adsorption. On the perfect surface, since the fivefold titanium atom is surrounded by surface bridging oxygen atoms above it and has a water molecule bonding to it, the amino group NH2 is the adsorption group. However, because the pit surface exposes
more adsorption sites and has higher surface energy, RGD can adsorb rapidly on the surfaces by amino groups NH2 and NH3þ, and the carboxyl group COO� may edge out the adsorbed water molecules and bond to the surface titanium atom. Moreover, the surface with higher surface energy has more adsorption energy of RGD.

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    ABSTRACT: Immobilization of RGD peptides on titanium (Ti) surfaces enhances implant bone healing by promoting early osteoblastic cell attachment and subsequent differentiation by facilitating integrin binding. Our previous studies have demonstrated the efficacy of RGD peptide immobilization on Ti surfaces through the electrodeposition of poly(ethylene glycol) (PEG) (RGD/PEG/Ti), which exhibited good chemical stability and bonding. The RGD/PEG/Ti surface promoted differentiation and mineralization of pre-osteoblasts. This study investigated the in vivo bone healing capacity of the RGD/PEG/Ti surface for biomedical application as a more osteoconductive implant surface in dentistry. The RGD/PEG/Ti surface was produced on an osteoconductive implant surface, i.e. the grit blasted micro-rough surface of a commercial oral implant. The osteoconductivity of the RGD/PEG/Ti surface was compared by histomorphometric evaluation with an RGD peptide-coated surface obtained by simple adsorption in rabbit cancellous bone after 2 and 4 weeks healing. The RGD/PEG/Ti implants displayed a high degree of direct bone apposition in cancellous bone and achieved greater active bone apposition, even in areas of poor surrounding bone. Significant increases in the bone to implant contact percentage were observed for RGD/PEG/Ti implants compared with RGD-coated Ti implants obtained by simple adsorption both after 2 and 4 weeks healing (P<0.05). These results demonstrate that RGD peptide immobilization on a Ti surface through electrodeposited PEG may be an effective method for enhancing bone healing with commercial micro-rough surface oral implants in cancellous bone by achieving rapid bone apposition on the implant surface.
    Acta biomaterialia 04/2011; 7(8):3222-9. · 5.68 Impact Factor


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May 23, 2014