Hierarchically Structured Electrospun Fibers

Abstract

Abstract:Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures-including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications-will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials.

Eco-friendly Electrospun Polymeric Nanofibers-Based Nanocomposites for Wound Healing and Tissue Engineering

“…This was reported upon developing nanofibers using different patterns of collectors with different geometries and movements as shown in Fig. 3 (Zander 2013). It was also reported that using stationary plate collector would produce unaligned nanofibers with totally random orientation, while parallel conductive rods are able to produce highly aligned electrospun nanofibers due to the gap present between the two rods that is able to suspend the electrospun nanofibers between the two rods (Chew et al 2005;Pham et al 2006;Zander 2013).…”

“…3 (Zander 2013). It was also reported that using stationary plate collector would produce unaligned nanofibers with totally random orientation, while parallel conductive rods are able to produce highly aligned electrospun nanofibers due to the gap present between the two rods that is able to suspend the electrospun nanofibers between the two rods (Chew et al 2005;Pham et al 2006;Zander 2013). Highly oriented nanofibers can also be produced through using either revolving discs or revolving drums (Teo and Ramakrishna 2006) (Fig.…”

“…Electrospinning parameters are classified into three main categories which are: (i) processing (controlled) variables, (ii) ambient (uncontrolled) variables, and (iii) the solution variables (Huang et al 2003;Pham et al 2006;Zander 2013). Electrospinning parameters are summarized in Table 1.…”

“…3 Different patterned electrospinning collectors. Adopted with modification from Zander (2013) compared to those obtained upon using stationary solid collector (Liu and Hsieh 2002).…”

Core-Sheath Nanofibers as Drug Delivery System for Thermoresponsive Controlled Release

“…[1][2][3] Coaxial electrospinning, comparing to simple single and blended spinning, is used to prepare core-sheath structured nanofibers with outstanding properties and multifunctionality for additional functional applications, [4][5] such as biotechnology, textiles, membranes, composites. [6][7][8][9] Stimuli-responsive polymers have been widely used in intelligent or smart materials with a great promise in drug delivery systems, sensors, and biomaterials, [10][11][12][13][14][15] due to these polymers can respond to changes in temperature, pH, light, or ionic strength. For example, poly(N-isopropylacrylamide) (PNIPAAm) is a typical temperature-sensitive polymer.…”