Electrospun nanofibers of a degradable poly(ester amide). Scaffolds loaded with antimicrobial agents

Abstract

Electrospinning conditions were evaluated to prepare micro/nanofibers of a biodegradable poly(ester amide) constituted by L-alanine, 1,12-dodecanediol and sebacic acid. 1,1,1,3,3,3-Hexafluroroisopropanol appeared as the most appropriate solvent to obtain fibers in a wide range of electrospinning conditions that allowed tuning the final diameter size. Fiber diameter increased with the flow, distance between the needle tip and the collector and decreasing voltage, which made it possible to obtain homogeneous fibers in the 1700-320 nm range. Fibers were loaded with antimicrobial agents like silver and chlorohexidine, and the influence of agent concentration in the electrospinning solutions on the fiber diameter size was determined. The polymer was able to crystallize during the electrospinning process, giving rise to a structure slightly different from that obtained by solution crystallization and related to that attained after crystallization from the melt state. Addition of antimicrobial agents had little effect on the degree of crystallinity, although it decreased slightly when chlorhexidine was employed. Scaffolds prepared from the silver and chlorhexidine loaded samples supported cell adhesion and proliferation. Furthermore, a clear and well differentiated antimicrobial effect against both Gram-positive (e.g. M. luteus) and Gram-negative (e.g. E. coli) bacteria was demonstrated.

Semiconducting, biodegradable and bioactive fibers for drug delivery

“…This expected result is consistent with the lack of bactericidal activity of PLA, P3TMA and IBU. In contrast, halos of inhibition were observed for PLA-P3TMA electrospun fibers loaded with TCS, CHX and CIP, evidencing the antimicrobial activity of these drugs [36,56,57,60]. The formation of such Figure 11.…”

“…Furthermore, the release of CHX in PBS-EtOH was also very fast, reaching a value of 70% after only seven hours of exposure (Figure 11b). Previous studies [56][57][58] indicated that the release kinetics of these drugs can be explained by the Higuchi and first-order models, which are usually combined to describe the first (from the beginning to 60%) and second (40-100%) stages of the release [59], respectively. In both cases, the delivery process is explained by the diffusion of the drug through the polymer matrix, which is facilitated by the ethanol-induced swelling of PLA [36].…”

Preparation of micro-molded exfoliated clay nanocomposites by means of ultrasonic technology

“…They are widely employed for many applications such as sutures, materials for tissue regeneration, orthopedics, scaffolds and systems for controlled release of drugs in medicine [7][8][9][10][11][12]. The great interest in PLA based bionanocomposites is directly supported by the significant increase in the number of derived scientific publications [13], which clearly demonstrates an improvement of biodegradation rate and mechanical, thermomechanical and gas barrier properties [14,15].…”

Poly(ester amides) (PEAs) – Scaffold for tissue engineering applications

“…The diffused ESR spectrum of 4-amino-TEMPO also proved homogenous dispersion of the drug at molecular level. As evident from all these properties discussed above, electrospun PEA [66], with permission from Springer).…”