Tendon and ligament (T/L) injuries present an important clinical challenge due to their intrinsically poor healing capacity. Natural healing typically leads to the formation of scar-like tissue possessing inferior mechanical properties. Therefore, tissue engineering has gained considerable attention as a promising alternative for T/L repair. In this study, we fabricated braided nanofibrous scaffolds (BNFSs) as a potential construct for T/L tissue engineering. Scaffolds were fabricated by braiding 3, 4, or 5 aligned bundles of electrospun poly(L-lactic acid) nanofibers, thus introducing an additional degree of flexibility to alter the mechanical properties of individual scaffolds. We observed that the Young's modulus, yield stress, and ultimate stress were all increased in the 3-bundle compared to the 4- and 5-bundle BNFSs. Interestingly, acellular BNFSs mimicked the normal tri-phasic mechanical behavior of native tendon and ligament (T/L) during loading. When cultured on the BNFSs, human mesenchymal stem cells (hMSCs) adhered, aligned parallel to the length of the nanofibers, and displayed a concomitant realignment of the actin cytoskeleton. In addition, the BNFSs supported hMSC proliferation and induced an upregulation in the expression of key pluripotency genes. When cultured on BNFSs in the presence of tenogenic growth factors and stimulated with cyclic tensile strain, hMSCs differentiated into the tenogenic lineage, evidenced most notably by the significant upregulation of Scleraxis gene expression. These results demonstrate that BNFSs provide a versatile scaffold capable of supporting both stem cell expansion and differentiation for T/L tissue engineering applications.

Efforts to increase aerobic capacity and LBM among soccer players in the off-season may help reduce in-season injury.

An emerging approach to repair and replace a great number of the ligament and tendon injuries that occur each year is the use of tissue engineering principles to fabricate replacement tissues. One of the current challenges in tendon/ligament tissue engineering is fabricating scaffolds that possess both the proper mechanical and biological properties. A promising strategy to produce such scaffolds is electrospinning. Electrospinning uses a high-voltage power supply to draw viscous polymer solutions into ultra-fine fibers with nanometer-scale diameters, thus structurally mimicking native extracellular matrix components, such as collagen fibrils. Nano-scale fibers have been previously shown to enhance cellular proliferation, as well as stimulate cells to maintain morphology and phenotype when compared to scaffolds composed of larger fibers [1]. Furthermore, electrospinning provides researchers the flexibility of fabricating aligned scaffolds with isotropic mechanical properties to mimic native tissue mechanics [2]. However, scaffolds composed of aligned electrospun nanofibers often do not possess the elasticity and tensile strength required to properly carry out the mechanical function of tendon/ligament tissues. One approach that has been used to enhance mechanical properties of fibrous scaffolds is to weave multiple fibrous bundles into a braided scaffold. [3]. In this study, we fabricated a novel tendon/ligament tissue engineering scaffold that combines enhanced biological properties of electrospun scaffolds with enhanced mechanical properties through braiding. Furthermore, our approach offers the versatility to tailor tensile strength and elasticity of the braided scaffolds simply by varying the pattern of braiding, making it possible for researchers to construct tendon/ligament scaffolds with various mechanical properties.

In this chapter authors explain electrospinning technique and how to involve electrospinning technique in biomedical engineering. It is a materials processing technique that uses an electric field to draw a polymer solution into ultra-fine fibers.   Further, this chapter aims to provide important information to researchers who aim to use electrospinning in their research. The electrospinning technique was invented a few decades ago and has recently been modified for biomedical applications.

The University of Wisconsin-Madison chapter of Engineers Without Borders (EWB-UW) has teamed with Rotary International and the municipality of Nejapa, El Salvador to construct a wastewater collection and treatment system for two developing communities, La Granja and Nuevo Ferrocarril. The communities have no centralized wastewater collection system resulting in raw sewage discarded to the streets. The first section of the project involves the construction of a wastewater collection system in the two communities for centralized treatment. Nejapa built a wastewater treatment plant in 2000, but due to overloading and poor maintenance, the system is currently failing. EWB-UW is currently in the process of discussing implementation of a preliminary design with Nejapa. The wastewater treatment plant update involves three different phases. The three phases include an update on their primary clarifier, the construction of a bio-tower and secondary clarifier, and the reconstruction of the existing wetland.