Extrusion-based bioprinting of hydrogel scaffolds is challenging due to printing-related issues, such as the lack of capability to precisely print or deposit hydrogels onto three-dimensional (3D) scaffolds as designed. Printability is an index to measure the difference between the designed and fabricated scaffold in the printing process, which, however, is still under-explored. While studies have been reported on printing hydrogel scaffolds from one or more hydrogels, there is limited knowledge on the printability of hydrogels and their printing processes. This paper presented our study on the printability of 3D printed hydrogel scaffolds, with a focus on identifying the influence of…
3D bioprinting techniques have been attracting attention for tissue scaffold fabrication in nerve tissue engineering applications. However, due to the inherent complexity of nerve tissues, bioprinting scaffolds that can appropriately promote the regeneration of damaged tissues is still challenging. This paper presents our study on bioprinting Schwann cell-laden scaffolds from low-viscosity hydrogel compositions including RGD modified alginate, hyaluronic acid and fibrin, with a focus on investigating the printability of hydrogel compositions and characterizing the functions of printed scaffolds for potential use in nerve tissue regeneration. We assessed the rheological properties of hydrogel precursors via temperature, time and shear rate sweeps,…
Peripheral nerve tissue requires appropriate biochemical and physical cues to guide the regeneration process after injury. Bioprinted peptide-conjugated sodium alginate (PCSA) scaffolds have the potential to provide physical and biochemical cues simultaneously. Such scaffolds need characterisation in terms of printability, mechanical stability, and biological performance to refine and improve application in nerve tissue regeneration. In this study, it was hypothesized that 3D scaffold printed with low concentrated multiple PCSA precursor would be supportive for axon outgrowth. Therefore, a 2% (w/v) alginate precursor was conjugated with either arginine-glycine-aspartate (RGD) or tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptides, or a mixture of RGD and YIGSR (1:2)…
Three-dimensional (3D) bioplotting has been widely used to print hydrogel scaffolds for tissue engineering applications. One issue involved in 3D bioplotting is to achieve the scaffold structure with the desired mechanical properties. To overcome this issue, various numerical methods have been developed to predict the mechanical properties of scaffolds, but limited by the imperfect representation of one key feature of scaffolds fabricated by 3D bioplotting, i.e., the penetration or fusion of strands in one layer into the previous layer. This paper presents our study on the development of a novel numerical model to predict the elastic modulus (one important index…
Tissue scaffolds fabricated by three-dimensional (3D) bioprinting are attracting considerable attention for tissue engineering applications. Because the mechanical properties of hydrogel scaffolds should match the damaged tissue, changing various parameters during 3D bioprinting has been studied to manipulate the mechanical behavior of the resulting scaffolds. Crosslinking scaffolds using a cation solution (such as CaCl2) is also important for regulating the mechanical properties, but has not been well documented in the literature. Here, the effect of varied crosslinking agent volume and crosslinking time on the mechanical behavior of 3D bioplotted alginate scaffolds was evaluated using both experimental and numerical methods. Compression…
Tissue regeneration with scaffold is one of the most promising approaches now a day, where application of dispensing-based rapid prototyping technique is drawing attention due to its capability to offer operational flexibility and print complex structure with utmost uniformity. In a pneumatic dispensing system, it is a critical issue to control the flow rate of biomaterial from dispensing tip, as some variables (material viscosity, temperature, needle geometry, and dispensing pressure) regulates the flow rate . In this context, model equations can play a vital role to control and predict the flow rate of dispensing material, and thus can eliminate the…