A silicone-based controlled-release device for accelerated proteolytic debridement of wounds.

A new device for rapid enzymatic debridement of cutaneous wounds has been developed using a controlled-release, silicone-based, dried emulsion. A dehydrated serine protease of the subtilisin family, previously untested for wound debridement, was incorporated into the emulsion. This device exhibited excellent storage stability. Moisture from the wound triggered an even, reproducible, and complete release of the enzyme within the first 8 hours. The device maintains a moist wound environment that allows the enzyme to achieve nearly complete digestion of the hardened eschar of full-thickness burns in a porcine model after an exposure period of 24 hours. Debridement was faster than in untreated wounds or wounds treated with a currently available enzyme ointment. Following rapid enzymatic debridement, healing appeared to progress normally, with no histological evidence of damage to adjacent healthy tissue.

Comments on total platinum concentration and platinum oxidation states in body fluids, tissue, and explants from women exposed to silicone and saline breast implants by IC-ICPMS.

The paper by Lykissa and Maharaj (Lykissa, E. D.; Maharaj, S. V. M Anal. Chem. 2006, 78, 2925-2933) purports to provide evidence that the urine of women with silicone breast implants contain 60 to over 1700 times more platinum in their urine that the urine of people with no known exposure to platinum. Further, they purport to show evidence that the platinum used in the manufacture of breast implants (Pt0) is converted by a unknown process to yield highly oxidized platinum species, stable in biological matrixes, up to and including Pt6+. This correspondence poses three questions associated with the work and directs the reader's attention to the data, which clearly show that the blood and urine platinum levels in implanted women and their healthy control group were not significantly different from one another.

"Sweet silicones": biocatalytic reactions to form organosilicon carbohydrate macromers.

Immobilized lipase B from Candida antarctica (Novozyme 435) catalyzed the regioselective formation of ester bonds between organosilicon carboxylic diacids and a C1-O-alkylated sugar under mild reaction conditions (i.e., low temperature, neutral pH, solventless). Specifically, the acid-functionalized organosilicones reacted with the primary hydroxyl group at the C6 position of alpha,beta-ethyl glucoside during the regioselective esterification. The pure organosilicon-sugar conjugates were prepared in a one-step reaction without protection-deprotection steps and without activation of the acid groups with the integrity of the siloxane bonds. [reaction: see text]

Enzyme-catalysed siloxane bond formation.

Biosilicification occurs on a globally vast scale under mild conditions. Although research has progressed in the area of silica biosynthesis, the molecular mechanisms of these interactions are effectively unknown. The natural production of silica in the Tethya aurantia marine sponge, Cylindrotheca fusiformis diatom, and Equisetum telmateia plant appear to be similar. However, the studies were complicated mechanistic queries due to the use of silicic acid analogues. Given these complications, a carefully chosen model study was carried out to test the ability of enzymes to catalyse the formation of molecules with a single siloxane bond during the in vitro hydrolysis and condensation of alkoxysilanes. Our data suggest that homologous lipase and protease enzymes catalyse the formation of siloxane bonds under mild conditions. Non-specific interactions with trypsin promoted the in vitro hydrolysis of alkoxysilanes, while the active site was determined to selectively catalyse the condensation of silanols.