Nouvelles morphologies de fibres électrofilées de polymère thermosensible

Abstract

This thesis presents a study on the possibility of obtaining scaffolds based on thermosensitive polymers presenting different morphologies for drug delivery applications. These scaffolds were obtained by electrospinning poly (N-vinylcaprolactam) (PNVCL), a thermosensitive polymer, in the pure state, as well as mixed with polycaprolactone (PCL), a biodegradable polymer. The processing parameters as well as the properties of the solutions to be electrospun, were optimized in order to create smooth, continuous, and beadless PNVCL fibers. A solution of (PNVCL) / (PCL) blend was then prepared using four different preparation methods. These methods are based on the use of either water or chloroform with concentrations of 42wt% and 30wt% respectively. The blend solutions were electrospun using the processing parameters that had been optimized for PNVCL. Then, Ketoprofen, a hydrophobic drug, was added to PNVCL and PNVCL/PCL solution blend before electrospinning to test those fibers for drug delivery. Finally, core-shell fibers were obtained using coaxial electrospinning with 42 wt% concentration of PNVCL/PCL aqueous solution for the shell and 30 wt% concentration of the PEG aqueous solution for the core. The morphologies of the resulting scaffolds were characterized by scanning electron microscopy (SEM). The lower critical solution temperature (LCST), which is the temperature below which the polymer is soluble in water and above which it precipitates was evaluated using differential scanning calorimetry (DSC). The drug entrapment efficiency (EE) and release of the obtained fibers scaffold were evaluated using an UV-visible spectrophotometer. Cross sections of PNVCL/PCL blend fibers and core-shell fibers were characterized using high resolution (SEM) in order to determine the PCL particle size within fibers and visualize the core-shell morphology of the resulting fibers. A membrane with smooth and continuous nanofibers was obtained by optimizing the electrospinning of PNVCL. The addition of PCL to the solution resulted in control of the LCST and the hydrophobicity of the membrane. It was also shown that the drug release of hydrophobic drug can be controlled by the morphology of those PCL/PNVCL blends. Finally, it has been possible to manufacture core-shell fibers by coaxial electrospinning of PNVCL.

Date	12 Jan 2017
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Nicole R. Demarquette (Supervisor)