Elimination of stick-slip of elastomeric sutures by radiofrequency glow discharge deposited coatings

Fine elastomeric sutures intended for cardiovascular surgery can exhibit "s tick-slip" behavior as they are pulled through tissue; the resulting oscill atory force can damage delicate tissue or cause sutures to snap. To elimina te this undesirable effect, sutures were surface-modified using a radiofreq uency glow discharge in a vapor of either hexamethyldisiloxane or hexamethy ldisilazane, to produce a thin polymeric coating on the suture. The same co atings were also deposited onto aluminized tape to facilitate their charact erization by measurement of air/water contact angles and by X-ray photoelec tron spectroscopy. Coatings from both monomers were found to be very hydrop hobic, The hexamethyldisiloxane glow discharge coatings underwent negligibl e oxidation when stored in air, and thus remained stable over a shelf-life period akin to what may be required of sutures. The hexamethyldisilazane gl ow discharge coatings, in contrast, incorporated substantial amounts of oxy gen over a 3-month period. The coatings did not measurably alter the tensil e properties of the sutures. The frictional properties of coated sutures we re assessed by measuring the dynamic friction between the suture and ovine myocardium. Both coatings were effective in removing the inherent stick-sli p behavior of polybutester sutures in this model. The coatings remained int act after several passes and proved to be robust and efficacious under vari ous strain regimes. (C) 2000 John Wiley & Sons, Inc.