Functional electrospun nanofibrous scaffolds for biomedical applications

Abstract

Functional nanofibrous scaffolds produced by electrospinning have great potential in many biomedical applications, such as tissue engineering, wound dressing, enzyme immobilization and drug (gene) delivery. For a specific successful application, the chemical, physical and biological properties of electrospun scaffolds should be adjusted to match the environment by using a combination of multi-component compositions and fabrication techniques where electrospinning has often become a pivotal tool. The property of the nanofibrous scaffold can be further improved with innovative development in electrospinning processes, such as two-component electrospinning and in-situ mixing electrospinning. Post modifications of electrospun membranes also provide effective means to render the electrospun scaffolds with controlled anisotropy and porosity. In this article, we review the materials, techniques and post modification methods to functionalize electrospun nanofibrous scaffolds suitable for biomedical applications.

Figure 1

Field-emission scanning electron microscopic images of lecithin fibers prepared at different solution concentrations (from below to above the critical concentration for entanglement). (From Ref. [77] with permission)

Figure 2

Electrospun scaffolds from 5 wt% total concentration of mixtures with PEO to casein ratio at (a) 100:0, (b) 80:20, (c) 50:50, (d) 20:80, (e) 5:95, and (f) 20:80 at 10% concentration. (From Ref. [108] with permission)

Figure 3

Drug (cefoxitin sodium) release profiles (cumulative curve-top and differential curve-bottom) from medicated electrospun scaffolds. The data represents the mean ± S.D. (n = 5 scaffolds): (a) medicated PLGA with 1 wt% drug, (b) medicated PLGA/PLA/PEG-b-PLA blend with 5 wt% drug, and (c) medicated PLGA with 5 wt% drug. (From Ref. [45] with permission)

Figure 4

Bioactivity of released DNA in the transfection of MC3T3 cells. (a) Naked DNA added directly to cell medium, (b) cells transfected with control DNA complex (Fugene 6), (c) DNA containing scaffold incubated with cell for 4 h, then removed, (d) released DNA from scaffold complexed with Fugene 6. Scale bar 100 μm. (From Ref. [47] with permission)

Figure 5

Confocal micrographs of immunostained myosin filaments in SMCs after 1 day of culture; (a) on aligned nanofibrous scaffold, (b) on aligned nanofibrous scaffold, overlay image on the aligned fiber, and (c) on tissue culture polystyrene as control. (From Ref. [100] with permission)

Figure 6

(a) SEM images of cardiac myocytes cultured on uniaxially stretched aligned PLLA electrospun scaffolds, (b) corresponding confocal micrograph of (a); (c) electrical response of cardiac myocytes on electrospun scaffolds (action potentials were measured using a voltage-sensitive dye di-8-ANEPPS and a micro scale optical recording system). (From Ref. [133] with permission)

Figure 7

Schematic diagram of (a) multilayer electrospinning and (b) mixing electrospinning. (From Ref. [134] with permission)

Figure 8

SEM image of PLA/clay nanocomposite scaffold by electrospinning and salt leaching/gas foaming methods. (From Ref. [136] with permission)

Figure 9

Visualization of fluorescently labeled protein encapsulated in polymer fibers using visible (a) and ultraviolet (b) light. (From Ref. [51] with permission)

Figure 10

A setup used to generate core-shelled structure by electrospinning. (From Ref. [138] with permission)

Figure 11

Characteristic fluorescent micrographs showing the variation in fiber diameter that results from cell encapsulation. Flow rate conditions: (A) cell suspension, 10⁻¹² m³/s, polymer solution, 10⁻¹¹ m³/s; (B) cell suspension, 10⁻⁸ m³/s, polymer solution 10⁻⁷ m³/s. (From Ref. [141] with permission)

Figure 12

A setup of blowing-assisted electrospinning device that can process materials usually difficult to be electrospun. (From Ref. [32] with permission)

Figure 13

Surface modification scheme for galactose conjugation to PCLPEEP nanofiber mesh and spin-cast film. (From Ref. [142] with permission)

Figure 14

SEM images of hepatocytes after 8 days of culture: (a–c) hepatocytes cultured on galactosylated spin-cast film formed around spheroids; (d–f) in contrast, hepatocytes cultured on galactosylated electrospun scaffold showed aggregates engulfed the functional nanofibers. (From Ref. [142] with permission)