Antimicrobial Activity of Amphiphilic Triazole-Linked Polymers Derived from Renewable Sources

Conventional engineered polymers are strong, stable, and can interact desirably within the human body in implants and medical devices. However, bacterial colonization of medical devices and implants constructed from these materials results in numerous hospital acquired infections (HAI) and deaths each year. Polytriazole based plastics containing triazole rings and fatty acid derivatives have been synthesized from biological sources without catalysts or solvents. In this study, three amphiphilic polytriazoles with varying triazole density and hydrophilic/hydrophobic segments demonstrated broad spectrum, contact antimicrobial properties against both Gram positive and negative bacteria. SEM analysis of bacteria killed by these polymers evidence membrane damage, indicating that these polymers act by direct contact with bacterial membranes. Surface hydrophobicity of these polymers increased with increasing triazole group density, which also improved the antimicrobial efficacy. This work demonstrates that amphiphilic polytriazoles have antimicrobial properties and that future utilization of triazole modified polymers may produce self-sterilizing materials which resist bacterial contamination and formation of antibiotic resistant organisms, ideal characteristics for medically relevant biomaterials

Background interference on the color of dental composite materials with different thickness by digital contrast

In this work the color dependence of resin composites with the background color was evaluated. The objective was to measure since what thickness the color of the sample stops being influenced by the color of the background over which the resin is placed and the methodology used in experiment was based in analyzing the contrast of digital images of the sample over a black background. The results shown that since 0.8 mm the images contrast becomes almost constant; it prove that since this thickness the color of resin composite depends on the optical resin properties only. The experiment was repeated under three conditions of luminosity to evaluate the influence of it on the image contrast and the results obtained were identical