Thermal Characterizations of Silver-containing Bioactive Glass-coated Sutures

Abstract

This study utilized and compared a number of thermal analysis methods to characterize the thermal properties of commercial sutures with and without antimicrobial coatings of silver-doped bioactive glass (AgBG) interlocking particulates. The effect of a slurry dipping technique used to coat resorbable Vicryl® (polyglactin 910) and non-resorbable Mersilk® surgical sutures with AgBG was investigated using conventional differential scanning calorimetry (DSC), high speed calorimetry (or HYPERDSC™), and modulated temperature DSC (MTDSC). These methods were compared in terms of their ability to resolve the thermal transitions of the types of suture materials. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) were used to verify the thermal degradation temperatures of these materials and to quantify the AgBG coatings on the sutures. The use of complementary thermal analysis techniques enabled the understanding of the effect of the AgBG coating technique on the morphological properties of the sutures. The slurry dipping technique had no significant effect on the thermal transitions of both types of materials. The use of high speed calorimetry through DSC offered better resolution for the transitions that appeared to be weak through conventional heating regimes, and was able to separate broad double transitions. Furthermore, it was shown not to compromise either the melting temperature or the enthalpy of melting. Therefore this method allows for the accurate determination of thermal transitions through much shorter experimental times thus allowing for an increased sample throughput. The combined DTA and TGA indicated that a greater AgBG coating was obtained in the case of the Mersilk® sutures.