Antibiotic treatment of silk to produce novel infection-resistant biomaterials

Abstract

Dye-like applications of antibiotics to silk produce infection-resistant materials for potential use in biomedical applications. Two antibiotics, doxycycline (doxy) and ciprofloxacin (cipro), are applied under a variety of conditions to silk and to silk that has previously been hydrolyzed at 40degreesC for 20, 40, and 60 minutes. FTIR spectroscopic analyses indicate that the drastically increased sorption of antibiotics by hydrolyzed silk is attributable to both chemical and conformational changes that occur with the hydrolysis. The high sorption of doxy by hydrolyzed silk does not necessarily yield a more infection-resistant material, as determined by a zone of inhibition test. Conversely, the same hydrolysis considerably increases both the sorption of cipro and the zone of inhibition of cipro-treated silk dyed at 65 and 85degreesC.