Electrospun Polymeric Nanofibers: Processing, Properties, and Controlled-Release Applications
Open Access
- Author:
- Metzger, Melissa
- Area of Honors:
- Chemical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Patrick Mather, Thesis Supervisor
Scott Thomas Milner, Thesis Honors Advisor - Keywords:
- polymers
electrospinning
polycaprolactone
drug release
controlled release
drug delivery
peppas
rhodamine b
rhodamine 6g - Abstract:
- The effect of fiber diameter and electrospinning method on the controlled release of small-molecules from electrospun poly-(ε-caprolactone) nanofibers was investigated in this study with the goal being to modulate release of two different molecules from two different populations of fibers. Nanofibers of differing diameters were fabricated by spinning polymer solutions of varying mass percents of poly-(ε-caprolactone), dimethylformamide, chloroform, and a model drug (either Rhodamine B or Rhodamine 6G) using both single-needle and dual-needle setups. Characterization via scanning electron microscopy (SEM) revealed that the manipulation of mass percent PCL in the spinning solution successfully yielded fibers of different diameters and that the dual-spun samples indeed contained fibers with two distinct average diameters. The fiber mats demonstrated tensile and thermal properties that were mostly in agreement with literature values, and the discrepancies could be explained by the morphological differences between polymer chains in nanofibers compared to a bulk polymer. The resulting fiber mats were then tested in vitro over 120 h to determine the drug release profiles from each fiber diameter and spinning method. For both the single-spun and dual-spun samples, drug release profiles exhibited a burst release phase within the first 2-4 h followed by asymptotic release for the rest of the experiment. This burst characteristic was attributed to a possible accumulation of dye on and near the surface of the fibers, and/or to the hydrophobic nature of PCL preventing thorough penetration of water molecules into the core of the fibers over the relatively short experimental period. Ultimately, the total release was relatively low, with a maximum of 30% for the single-spun fibers and 9% for the dual-spun fibers. Observed changes in thermal properties after immersion in PBS were also attributed to the effect on morphology of water absorption and chain annealing at 37°C.