Development and characterization of biodegradable sutures made of electrospun fibers with ampicillin
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Surgical sutures are one of the most frequently used devices in emergency rooms and operating theatres. Due to the large number of surgical site infections caused by suture implantations, there is an increasing need for the application of sutures with antimicrobial properties, especially biodegradable sutures with the controlled release of antimicrobial agents. A study was carried out to develop these suture fibers by electrospinning and evaluate selected properties of the fibers. As electrospinning is a relatively new spinning method and fundamental understanding of the technique has not been established, the spinning process and the influence of the processing parameters on the fiber properties were studied as well. Polycaprolactone, a biodegradable polymer used in biomaterials approved by the Food and Drug Administration (FDA), was the polymer selected. The antimicrobial agent, which was incorporated in the polymer solution to provide the produced fibers with antimicrobial properties, was ampicillin sodium salt. The selected fiber properties included physical and mechanical properties, antimicrobial properties, and the release of ampicillin from the fibers, as well as biodegradation properties. One of the major goals of the study was to establish methodologies to collect and characterize electrospun nanofibers, which could be physically manipulated as required for suture applications. The use of a thin disk as the electrospinning collector to collect nanofiber bundles has been proved to be a feasible method to achieve this goal. Other findings of the dissertation included the following. Fibers with a wide range of diameters and percentages of crystallinity could be produced by varying the polymer solution properties (the polymer concentration and the addition of ampicillin sodium salt) and the spinning processing parameters (voltage, feedrate, and the distance from the needle tip to the collector). The as-spun fibers showed antimicrobial effectiveness on both S. aureus and K. pneumoniae. The ampicillin release was completed in 96 hours. The mass loss of degraded fibers was less than 3% in 12 weeks, but surface morphological changes were observed in samples that had been exposed to the biodegradation environment for six weeks.