Rational Design of Nanofiber Scaffolds for Orthopedic Tissue Repair and Regeneration

Abstract

This article reviews recent significant advances in the design of nanofiber scaffolds for orthopedic tissue repair and regeneration. It begins with a brief introduction on the limitations of current approaches for orthopedic tissue repair and regeneration. It then illustrates that rationally designed scaffolds made up of electrospun nanofibers could be a promising solution to overcome the problems that current approaches encounter. The article also discusses the intriguing properties of electrospun nanofibers, including control of composition, structures, orders, alignments and mechanical properties, use as carriers for topical drug and/or gene sustained delivery, and serving as substrates for the regulation of cell behaviors, which could benefit musculoskeletal tissue repair and regeneration. It further highlights a few of the many recent applications of electrospun nanofiber scaffolds in repairing and regenerating various orthopedic tissues. Finally, the article concludes with perspectives on the challenges and future directions for better design, fabrication and utilization of nanofiber scaffolds for orthopedic tissue engineering.

RGD functionalized poly(ε-caprolactone)/poly(m-anthranilic acid) electrospun nanofibers as high-performing scaffolds for bone tissue engineering RGD functionalized PCL/P3ANA nanofibers

“…The mechanical properties of electrospun nanofiber mats can be tailored by varying the composition using different types of polymers and polymer blends, and by adjusting the size of individual nanofibers [35]. The Young's modulus of nanofiber mats was determined from the slope of the linear region of stress-strain curve [36].…”

Biodegradable polymeric nanomaterials

“…The values are different from those obtained in equivalent bulk materials [27]. Indeed for fibre-based materials, the mechanical properties are affected by the polymer molecular weight, morphology, crystallinity, as well as the material size and shape such as porosity, pore area and fibre size, density and orientation [44]. For instance, when electrospun fibre-based materials are developed with aligned fibres, the modulus and the tensile strength increase and the mechanical behaviour becomes anisotropic in comparison to randomly arranged fibres [62,63].…”

“…The potential medical applications are in the development of scaffolds for tissue engineering, carriers of bioactive compounds and cells, and in wound dressings. Additionally, in-terms of positively promoting cell-polymeric matrix interactions, the high surface area of the nanostructured, nanofibrous scaffolds allows for oxygen permeability and provides sufficient space for nutrient and waste exchange [44]. Moreover, in wound dressings, fluid accumulation at the wound site is limited and the material pore size prevents bacterial penetration.…”

“…As a consequence, a higher modulus and strength are generally obtained. The mechanical behaviour of electrospun fibre-based materials may also be tailored by: applying thermal post-treatments, using polymer blends, crosslinking the fibres, modifying the fibre surface, as well as encapsulating nanoparticles [44]. Ramier et al have demonstrated that the incorporation of hydroxyapatite nanoparticles within PHB nanofibres increased the elastic modulus and the tensile strength by 67 % and 51 %, respectively.…”

Electrospinning for nano- to mesoscale photonic structures

“…Alignment of polymer backbone structures along fiber axes forms crystal domains [150][151][152], which have provided a foundation for optoelectronics such as nanofiber light sources with color tunability and waveguide capabilities and nanofiber lasers [39,146,148,. Biologically, hybrid nanofiber scaffolds have provided a cell niche conducive to improved attachment, proliferation, and cell differentiation [190][191][192][193][194][195][196][197][198], as well as targeted drug delivery carriers [198][199][200][201][202][203][204][205][206]. Filtration using ONFs [207] equipped with activated carbon has revealed adsorption of volatile organic compounds (VOCs) present in the air [208][209][210], and Scholten et al reported that adsorption and desorption of VOC by electrospun nanofibrous membranes (ENMs) were faster than that of conventional activated carbon [208].…”