Bone Repair Stimulation in Rat Mandible by New Chitosan Silver(I) Complexes

Abstract

Two new chitosan silver(I) complexes, [Ag(2CS)(H₂O)(NO₃)] and [Ag(2CS)(ahmp)(H₂O)] (CS = chitosan, Hahmp = 4-amino-6-hydroxy-2-mercaptopyrimidine) were synthesized and characterized on the basis of elemental analysis, spectral (FT-IR and solid-state ¹³C-NMR), morphological (SEM, matrix analysis, XRD, and XRPE), and thermal measurements. Chitosan behaves as a neutral ligand, coordinates Ag(I) through half of amino nitrogen centers, with the pendant glucose amine hydroxy functionality playing no role in coordination, while 4-amino-6-hydroxy-2-mercaptopyrimidine functions as mononegative bidentate, chelating through the deprotonated cyclic nitrogen and thione sulfur atoms. [Ag(2CS)(ahmp)(H₂O)] displays a significant potential bone regenerator in rat mandible. Forty male rats were divided into two groups: bone defect (control) and bone defect with [Ag(2CS)(ahmp)(H₂O)] (treated). The bone defects were stained with hematoxylin and eosin, and Masson's trichrome for histological analysis. The treated group shows faster and well organized bone formation in the defect in comparison to the control group which shows little new bone trabeculae and wide marrow cavities.

Keywords:

• Ahmp
• bone generation
• chitosan
• rat mandible
• silver

Acknowledgments

The authors wish to thank Mrs. Line Mongeon (Chemical Engineering Department, McGill University, Montréal, Canada) for running SEM and matrices analysis, and Dr. Fredrick Morin and Mr. Peter Fiurasek (Chemistry Department, McGill University, Montréal, Canada) for running solid state ¹³C-NMR spectra and TGA measurements, respectively.

Notes

^a C(2), ^b C(4), ^c C(5), ^d C(6) resonances of Hahmp (see Scheme 1 for numbering scheme).

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