Advances in Electrospun Poly(ε-caprolactone)-Based Nanofibrous Scaffolds for Tissue Engineering

Abstract

Tissue engineering has great potential for the restoration of damaged tissue due to injury or disease. During tissue development, scaffolds provide structural support for cell growth. To grow healthy tissue, the principal components of such scaffolds must be biocompatible and nontoxic. Poly(ε-caprolactone) (PCL) is a biopolymer that has been used as a key component of composite scaffolds for tissue engineering applications due to its mechanical strength and biodegradability. However, PCL alone can have low cell adherence and wettability. Blends of biomaterials can be incorporated to achieve synergistic scaffold properties for tissue engineering. Electrospun PCL-based scaffolds consist of single or blended-composition nanofibers and nanofibers with multi-layered internal architectures (i.e., core-shell nanofibers or multi-layered nanofibers). Nanofiber diameter, composition, and mechanical properties, biocompatibility, and drug-loading capacity are among the tunable properties of electrospun PCL-based scaffolds. Scaffold properties including wettability, mechanical strength, and biocompatibility have been further enhanced with scaffold layering, surface modification, and coating techniques. In this article, we review nanofibrous electrospun PCL-based scaffold fabrication and the applications of PCL-based scaffolds in tissue engineering as reported in the recent literature.

Keywords: biocompatibility; biomaterials; composite scaffolds; electrospinning; nanofibers; poly(ε-caprolactone) (PCL); scaffold fabrication; scaffold wettability; tissue engineering.

Figure 11

(a) Schematic of the fabrication process of the PCL/TiO₂@Cotton Janus membrane. (b) SEM image of the cross-section of the Janus membrane (top). Photographs of water droplets (~30 μL) on the TiO₂@Cotton layer (middle) and the reversed PCL fibrous layer (bottom). Water droplets were colored by dyes (Acid Violet 7, Sunset Yellow FCF, Alkali Blue 70). (c) SEM images of pristine cotton fabric and its partially enlarged cotton yarn; (d) single cotton yarn and its partial enlarged image; (e) TiO₂@Cotton yarn and its partial enlarged image. (f–i) SEM images, partial enlarged SEM images, and statistically average fiber diameters corresponding to PCL-7.5, PCL-10, PCL-12.5, and PCL-15, respectively [126].

Figure 1

Chemical structure of poly(ε-caprolactone).

Figure 2

Publications from the last two decades listed on Web of Science containing keywords “electrospinning” and “tissue engineering” and “PCL”, “electrospinning”, and “tissue engineering”.

Figure 3

Schematic of fabrication of a nanofibrous scaffold with the electrospinning technique. Electrospinning set-up with syringe pump, steel emitter, voltage supply, and ground collector.

Figure 4

Types of PCL-based nanofibers fabricated with electrospinning.

Figure 5

Types of emergent scaffolds fabricated from electrospun pristine PCL nanofibers, blend or composite nanofibers, and dual or multi-layer nanofibers.

Figure 6

Overview of biomaterials commonly blend-electrospun with PCL to fabricate composite PCL-based scaffolds.

Figure 7

Overview of biomaterials commonly blend-electrospun with PCL and their relative influence on scaffold bioactivity and mechanical strength.

Figure 8

Overview of scaffold post-electrospinning processing techniques for enhanced functionality or biocompatibility.

Figure 9

In vivo wound healing of gelatine-coated PCL nanofibers as well as gelatine-coated drug-loaded PCL nanofibers [120].

Figure 10

Burn wound healing progress at days 3, 7, and 14 for PCL, PCL/GLT, and PCL/GLT/LSLE electrospun fibrous mats [121].

Figure 12

Cumulative drug release profile of different PIP-loaded PCL formulations [129].

Figure 13

SEM micrographs of different layers of multilayered electrospun fibrous structures. The surface morphology and section view of MGPCL (a,b), The microstructure of SKMGPCL (c,d) and MSKPCL (e,f) [140].