|
Nanofibrous composite scaffolds of poly(ester amides) with tunable physicochemical and degradation properties.
Shilpaa Mukundan , Vinayak Sant , Sumit Goenka , Johnathan Franks , Lisa C. Rohan , Shilpa Sant
European Polymer Journal, Volume 68
Graphical abstract
Abstract
Polymeric elastomers
like Poly(1,3-diamino-2-hydroxypropane-co-polyol sebacate) (APS) have gained
importance in soft tissue engineering applications due to their tunable
mechanical properties and biodegradability. The fabrication of extracellular
matrix (ECM)-mimetic nanofibrous scaffolds using APS is however limited due to
its poor solubility in commonly used solvents, low viscosity and high
temperatures required for thermal curing. In this study, we have overcome these
limitations of APS by blending uncrosslinked APS pre-polymer with
polycaprolactone (PCL), and have successfully fabricated ECM-mimetic
nanofibrous APS scaffolds for the first time. The developed fibrous scaffolds
were further characterized for their physicochemical, thermal, mechanical and
degradation properties. Effects of APS:PCL weight ratios (0:1, 1:1, 2:1 and
4:1) and total polymer concentration (15–30% w/v) on the fiber morphology, tensile properties, chemical and thermal
properties of the APS–PCL composite
scaffolds were investigated. Higher APS concentrations in the polymer blend
resulted in formation of fused fibers and thus, increased fiber diameters. The
degree of hydration and consequently, degradation rate of the scaffolds
increased with the APS concentration. The FTIR and DSC studies showed selective
loss of APS polymer from composite scaffolds after degradation. Scaffolds with
1:1 APS:PCL ratio exhibited maximum elastic modulus (EM) of 30±2.5MPa compared to 0:1, 2:1 and 4:1 ratios. Increasing total polymer
concentrations (15–30% w/v) at constant
(2:1) APS:PCL ratio increased stiffness and tensile strength of the electrospun
scaffolds. Biocompatibility studies using C2C12 mouse myoblast cells showed
enhanced cell spreading on APS containing scaffolds after 6h as compared to
PCL-only scaffolds. Thus, the present study demonstrates successful development
of APS-based thermoset elastomeric nanofibrous scaffolds by blending with
semicrystalline PCL polymer for the first time. Tunable physicochemical,
mechanical and degradation properties of these composite APS–PCL scaffolds will be further exploited for skeletal muscle tissue
engineering applications.
|
