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Physical stability of arginine-glycine-aspartic acid peptide coated on anodized implants after installation.

Huh JB, Lee JY, Jeon YC, Shin SW, Ahn JS, Ryu JJ - J Adv Prosthodont (2013)

Bottom Line: The residual rate of peptide was significantly larger in the P-S group than in the other three groups (P<.05).The result of this study suggests that coating doses depend on coating method.Residual amounts of RGD peptide were greater for the physical adsorption method than the chemical grafting method.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, School of Dentistry, Dental Hospital, Dental Research Institute, Pusan National University, Yangsan, Republic of Korea.

ABSTRACT

Purpose: The aim of this study was to evaluate the stability of arginine-glycine-aspartic acid (RGD) peptide coatings on implants by measuring the amount of peptide remaining after installation.

Materials and methods: Fluorescent isothiocyanate (FITC)-fixed RGD peptide was coated onto anodized titanium implants (width 4 mm, length 10 mm) using a physical adsorption method (P) or a chemical grafting method (C). Solid Rigid Polyurethane Foam (SRPF) was classified as either hard bone (H) or soft bone (S) according to its density. Two pieces of artificial bone were fixed in a customized jig, and coated implants were installed at the center of the boundary between two pieces of artificial bone. The test groups were classified as: P-H, P-S, C-H, or C-S. After each installation, implants were removed from the SRPF, and the residual amounts and rates of RGD peptide in implants were measured by fluorescence spectrometry. The Kruskal-Wallis test was used for the statistical analysis (α=0.05).

Results: Peptide-coating was identified by fluorescence microscopy and XPS. Total coating amount was higher for physical adsorption than chemical grafting. The residual rate of peptide was significantly larger in the P-S group than in the other three groups (P<.05).

Conclusion: The result of this study suggests that coating doses depend on coating method. Residual amounts of RGD peptide were greater for the physical adsorption method than the chemical grafting method.

No MeSH data available.


Related in: MedlinePlus

Schematic representation of the chemical grafting group.
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Figure 1: Schematic representation of the chemical grafting group.

Mentions: We used anodized Cell Nest® implants (Osstem, Pusan, Korea) that measured 4.0 mm in width and 10 mm in height. Implants coated with RGD peptides were minimally exposed to light to avoid hardening of the FITC, a fluorescence marker. Implants were divided into 2 groups for coating by physical adsorption or chemical grafting. In the physical adsorption group, the anodized implant surface was coated with RGD peptide by immersion in a solution containing 0.2 mg/mL of RGD peptide for 12 hours in the dark. Residual solution on coated implants were removed using wrinkle-free paper (KimWipes™, Kimberly-Clark Co., Irving, Texas), and implants were dried thoroughly in nitrogen atmosphere. In the chemical grafting group, implants were coated by chemical immobilization using Silane. After briefly activating anodized surfaces with UV/O cleaner (Jelight Co Inc, Irvine, CA, USA), implants were immersed for 90 minutes in a 2.5% (v/v) APTES ethanol solution. Implant surfaces were then rinsed with ethanol and dried in a nitrogen atmosphere at 110℃ for 1 hour. Implants were then reacted with 0.1 mg/mL Succinimidyl-4-[N-maleimidomethyl] cyclohexane-1-carboxylate (SMCC) for 1 hour in the dark, rinsed with PBS and distilled water, and dried in a nitrogen atmosphere. To ensure peptide adhesion, a buffer solution (pH 6.6) was prepared by adding 0.2 mg/mL 4-(2-hydroxyethyl)-1-piperazine sulfuric acid (HEPES) to 10 mM thiamine pyrophosphate (TPP). Because thiol radicals are oxidized to disulfide when they that react with the cystein radicals of RGD peptide and lose their reactivity to maleimide radicals, implants were reacted for more than 30 minutes with a HEPES buffer solution containing TPP, which reduces disulfide. Since amine and benzyl phenyl sulphide (BPS) inhibit the reaction between each other, neither was suitable for our experiment. Maleimide radical-inserted titanium treated by anodic oxidation was reacted with the aforementioned peptide solution. At the completion of the reaction, titanium was rinsed with HEPES buffer followed by distilled water and dried in a nitrogen atmosphere. A single layer of APTES was formed on the anodized titanium surface, and then coated with RGD peptide, which was immobilized on the implant surfaces by reacting the 2 radicals of SMCC with the amine radical of APTES and the thiol radical of the peptides, respectively (Fig. 1).


Physical stability of arginine-glycine-aspartic acid peptide coated on anodized implants after installation.

Huh JB, Lee JY, Jeon YC, Shin SW, Ahn JS, Ryu JJ - J Adv Prosthodont (2013)

Schematic representation of the chemical grafting group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675298&req=5

Figure 1: Schematic representation of the chemical grafting group.
Mentions: We used anodized Cell Nest® implants (Osstem, Pusan, Korea) that measured 4.0 mm in width and 10 mm in height. Implants coated with RGD peptides were minimally exposed to light to avoid hardening of the FITC, a fluorescence marker. Implants were divided into 2 groups for coating by physical adsorption or chemical grafting. In the physical adsorption group, the anodized implant surface was coated with RGD peptide by immersion in a solution containing 0.2 mg/mL of RGD peptide for 12 hours in the dark. Residual solution on coated implants were removed using wrinkle-free paper (KimWipes™, Kimberly-Clark Co., Irving, Texas), and implants were dried thoroughly in nitrogen atmosphere. In the chemical grafting group, implants were coated by chemical immobilization using Silane. After briefly activating anodized surfaces with UV/O cleaner (Jelight Co Inc, Irvine, CA, USA), implants were immersed for 90 minutes in a 2.5% (v/v) APTES ethanol solution. Implant surfaces were then rinsed with ethanol and dried in a nitrogen atmosphere at 110℃ for 1 hour. Implants were then reacted with 0.1 mg/mL Succinimidyl-4-[N-maleimidomethyl] cyclohexane-1-carboxylate (SMCC) for 1 hour in the dark, rinsed with PBS and distilled water, and dried in a nitrogen atmosphere. To ensure peptide adhesion, a buffer solution (pH 6.6) was prepared by adding 0.2 mg/mL 4-(2-hydroxyethyl)-1-piperazine sulfuric acid (HEPES) to 10 mM thiamine pyrophosphate (TPP). Because thiol radicals are oxidized to disulfide when they that react with the cystein radicals of RGD peptide and lose their reactivity to maleimide radicals, implants were reacted for more than 30 minutes with a HEPES buffer solution containing TPP, which reduces disulfide. Since amine and benzyl phenyl sulphide (BPS) inhibit the reaction between each other, neither was suitable for our experiment. Maleimide radical-inserted titanium treated by anodic oxidation was reacted with the aforementioned peptide solution. At the completion of the reaction, titanium was rinsed with HEPES buffer followed by distilled water and dried in a nitrogen atmosphere. A single layer of APTES was formed on the anodized titanium surface, and then coated with RGD peptide, which was immobilized on the implant surfaces by reacting the 2 radicals of SMCC with the amine radical of APTES and the thiol radical of the peptides, respectively (Fig. 1).

Bottom Line: The residual rate of peptide was significantly larger in the P-S group than in the other three groups (P<.05).The result of this study suggests that coating doses depend on coating method.Residual amounts of RGD peptide were greater for the physical adsorption method than the chemical grafting method.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, School of Dentistry, Dental Hospital, Dental Research Institute, Pusan National University, Yangsan, Republic of Korea.

ABSTRACT

Purpose: The aim of this study was to evaluate the stability of arginine-glycine-aspartic acid (RGD) peptide coatings on implants by measuring the amount of peptide remaining after installation.

Materials and methods: Fluorescent isothiocyanate (FITC)-fixed RGD peptide was coated onto anodized titanium implants (width 4 mm, length 10 mm) using a physical adsorption method (P) or a chemical grafting method (C). Solid Rigid Polyurethane Foam (SRPF) was classified as either hard bone (H) or soft bone (S) according to its density. Two pieces of artificial bone were fixed in a customized jig, and coated implants were installed at the center of the boundary between two pieces of artificial bone. The test groups were classified as: P-H, P-S, C-H, or C-S. After each installation, implants were removed from the SRPF, and the residual amounts and rates of RGD peptide in implants were measured by fluorescence spectrometry. The Kruskal-Wallis test was used for the statistical analysis (α=0.05).

Results: Peptide-coating was identified by fluorescence microscopy and XPS. Total coating amount was higher for physical adsorption than chemical grafting. The residual rate of peptide was significantly larger in the P-S group than in the other three groups (P<.05).

Conclusion: The result of this study suggests that coating doses depend on coating method. Residual amounts of RGD peptide were greater for the physical adsorption method than the chemical grafting method.

No MeSH data available.


Related in: MedlinePlus