Calculation of the surface density of the RGD-containing peptide on allogenic bone using isotopic tracing technique / 中华骨科杂志

ABSTRACT

Objective To investigate the feasibility of determining the surface density of RGD-containing peptide on allogenic bone by isotopic tracing technique using RGD peptide labelled with 125Ⅰ,and the impact of the input concentration of RGD-containing peptide on the surface density,and to obtain the history between the surface density and the input concentration of RGD-containing peptide.Methods The synthetic RGD-containing peptide was labelled with 125Ⅰ,and the specific radioactivity was calculated.The reactive solutions of RGD-containing peptide with the radioactive 125Ⅰ-RGD as a probe were prepared at the input concentrations of 0.01 mg/ml,0.10 mg/ml,0.50 mg/ml,1.00 mg/ml,2.00 mg/ml,4.00 mg/ml.Using EDC as the cross-linking agent,the reaction was carried out by placing the allogenic bone pieces into the reactive solutions of RGD-containing peptide with different input concentrations.After the reaction,the surface density of RGD-containing peptide grafted onto the allogenic bone pieces was calculated by evaluating the radioactivity and the surface area of the bone pieces.The impact of the input concentration of RGD-containing peptide on the surface density was measured and the curve was ascertained.Results After measuring in the radiodensity γ-counter,the result showed the RGD peptides have been marked with 125Ⅰ successfully.The allogenic bone pieces were radioactive after the reaction,which demonstrated that the RGD-containing peptide had been grafted onto the surface of bone pieces successfully.It was also found that with the increasing of input concentration,the surface density raised.Conclusion The surface density of RGD-containing peptide is related to its input concentration.With the increasing of input concentration,the surface density raises to the saturation value gradually.