Bactericidal activity of chlorine-loaded carbide-derived carbon against Escherichia coli and Bacillus anthracis.

The authors investigated the bactericidal activity of high-chlorine-content nanoporous carbide-derived carbon (CDC) against the Gram-positive, spore-forming bacterium Bacillus anthracis and the common Gram-negative enteric bacterium Escherichia coli. Chlorine-loaded nanoporous CDC produced by thermochemical etching of metals and metalloids by chlorination of carbides can retain up to 40 wt % of chlorine. Etching temperature and the structure and composition of carbides allow tuning the porosity of CDC. The CDC chlorine content depends on the synthesis temperature, pore size, and metal carbide used during preparation. It was observed that chlorine-loaded CDC killed up to 100% of exposed E. coli and B. anthracis spores and vegetative cells in a dose and time-dependent manner. CDC containing higher concentrations of chlorine killed bacteria to a greater extent and faster than did CDC containing lesser concentrations of chlorine. The results suggest that chlorine-loaded CDC can be used in several commercial, defense, and industrial activities and processes to kill bacteria.

Analytical technique for quantification of selected resorbable calcium phosphate bone void fillers with the use of polarized-light microscopy.

Synthetic calcium phosphate bone void fillers promote varying rates of bone formation and material resorption depending on chemistry, porosity, pore structure, and implant site. The objective of this study was to quantify the resorption of a novel ultraporous beta-tricalcium phosphate cancellous bone void filler with simultaneous quantification of bone formation in a canine humerus model. Potential measurement error involved in conventional histomorphometry using Von Kossa stains inspired the development of a new technique. This technique utilizes bright-field and polarized-light microscopy in conjunction with image analysis software, allowing more accurate histomorphometry. This technique was validated with two separate controlled experiments. Scanning electron microscopy further supported the results. The findings suggest that the use of polarized-light microscopy combined with image analysis software can be an effective tool in simultaneously quantifying calcium phosphate resorption and bone formation.