RESUMO
BACKGROUND: The objective of this study was to evaluate xenograft degradation velocity when treated with 4-hexylresorcinol (4HR). METHODS: The scapula of a cow was purchased from a local grocery, and discs (diameter 8 mm, thickness 1 mm) were prepared by trephine bur. Discs treated with 4HR were used as the experimental group. Untreated discs were used as the control. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), antibacterial test, endotoxin test, and scanning electron microscopy (SEM) were performed on the discs. In vivo degradation was evaluated by the rat calvarial defect model. RESULTS: The XRD and FT-IR results demonstrated successful incorporation of 4HR into the bovine bone. The experimental disc showed antibacterial properties. The endotoxin test yielded results below the level of endotoxin contamination. In the SEM exam, the surface of the experimental group showed needle-shaped crystal and spreading of RAW264.7 cells. In the animal experiments, the amount of residual graft was significantly smaller in the experimental group compared to the control group (P = 0.003). CONCLUSIONS: In this study, 4HR was successfully incorporated into bovine bone, and 4HR-incorporated bovine bone had antibacterial properties. In vivo experiments demonstrated that 4HR-incorporated bovine bone showed more rapid degradation than untreated bovine bone.
RESUMO
The one-pot production and structural characterization of composites of silver nanoparticles with poly(p-Br/F-phenylsilane), Br/F-PPS, have been performed. The conversion of Ag+ ions to stable Ag0 nanoparticles is mediated by the copolymer Br/F-PPS having both possibly reactive Si-H bonds in the polymer backbone and C-Br bonds in the substituents along with relatively inert C-F bonds. Transmission electron microscopy and field emission scanning electron microscopy analyses show the formation of the composites where silver nanoparticles (less than 30 nm of size) are well dispersed over the Br/F-PPS matrix. X-ray diffraction patterns are consistent with that for face-centered-cubic typed silver. The polymer solubility in toluene implys that the cleavage of C-Br bond and the Si-F dative bonding may not be occurred appreciably at ambient temperature. Nonetheless, thermogravimetric analysis data suggest that some sort of cross-linking could take place at high temperature. Most of the silver particles undergo macroscopic aggregation without Br/F-PPS, which indicates that the polysilane is necessary for stabilizing the silver nanoparticles.
RESUMO
One-pot Si-Si/Si-O dehydrocoupling of hydrosilanes with alcohols (1:1.5 mole ratio), promoted by a mixture of AgNO3-H2PtCl6 (150/1 mole ratio) readily gave poly(alkoxysilane)s in good yield (62-91%). The addition of small amount of platinum complex to form nanoparticles facilitated the silicon polymer formation when compared to the reaction rate with AgNO3 alone. The primary/secondary hydrosilanes [p-X-C6H4SiH3 (X = H, CH3, OCH3, F), PhCH2SiH3, and (PhSiH2)2] and alcohols [MeOH, EtOH, (i)PrOH, PhOH, and CF3(CF2)2CH2OH] were used for the reaction. The weight average molecular weight and polydispersity of the poly(alkoxysilane)s were in the range of 1,690-7,100 Dalton and 1.44-3.49, respectively. The reaction of phenylsilane with ethanol (1:3 mole ratio) using the Ag-Pt complexes produced triethoxyphenylsilane only, as expected. The reaction of phenylsilane with Ge-132 produced an insoluble cross-linked gel.
