Skip to main content
2024 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Biomaterials

Biomaterials - Poster Session E

Poster B8 - Tensile Testing of Hyaluronic Acid Hollow Fibers

Saturday, October 26, 2024
10:00 AM - 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  Developing tissue engineered muscle using a modular approach requires building muscle fiber modules with soft biomaterials. The mechanical evaluation of these engineered fibers requires a low load testing environment. Therefore, a small-scale tensile testing machine was fabricated in-house, made of a load cell, linear actuator and 3D printed parts. In this study, the properties of hollow fibers composed of glycosaminoglycan-chitosan polyelectrolyte complexes were specifically explored using this machine. In particular, the mechanical properties of glycosaminoglycan-chitosan fibers made from 1.5% hyaluronic acid (HA), chondroitin sulfate A (CSA) and chitosan were analyzed. Testing parameters such as actuator speed were varied. The length of the fibers was varied from 30 mm to 45 mm with increments of 5 mm. Ultimately, a stress strain curve is produced to calculate the elastic modulus of these two types of fibers specifically at a rate of 5.20mm/s and a length of 35mm. In general, the low force system using 3D mounts will be further developed to determine what length and speed is best to test the tensile properties of the fibers.

Materials and

Methods:  The acellular hollow fibers were created using a 3D-printed coaxial extrusion chip, using 0.6 wt.% chitosan in 1% acetic acid as the shell fluid and a 1 wt.% HA + 2 wt.% CSA solution as the glycosaminoglycan (GAG) core fluid. Prior to beginning the tensile testing, fiber diameter and wall thickness was measured microscopically.

The tensile testing machine used a 100-g load cell (Phidget Inc.) to record the load and a 100-mm linear actuator (Actuonix) to control the strain and strain rate. The fiber was mounted on custom designed, 3D-printed fiber mounts on the load cell and the linear actuator. The distance between these 3-D mounts controlled the fiber test length. The fibers were tested at speeds ranging from 3.64 mm/s to 5.20 mm/s. The data collected from actuator and load cell were used to generate stress strain curves. The elastic modulus was obtained from the linear region of the curve. This process was repeated per fibre at different lengths and speed parameters.

Results, Conclusions, and Discussions: In general, there were significant differences between fibers made of 1.5% HA only and those made of 1% HA+1% CSA. For instance, 1.5% HA fibers took a longer amount of time to break (> 1s) which resulted in a higher maximum strain, whereas 1% HA+1% CSA fibers took approximately 1 second or less resulting in lower maximum strain values. This suggests that the 1% HA+1% CSA fibers are more brittle. In addition, we observed their diameters averaged 768 µm, while the 1.5% HA fibers had diameters of 995 µm. The mean elastic modulus for 1.5% HA fibers was 286.494 Pa while it was 1929.3244 Pa for the 1% HA+1% CSA fibers. It could also be stated that increasing the concentration of HA and adding CSA enhanced the tensile properties of the fibers because the 1% HA+1% CSA fibers ultimately had greater elastic modulus (Figure 2B). In terms of further research, the GAG formulations of the fibers must also be tested at various strain rates. In ongoing studies, we will also conduct characterization on hollow fibres that incorporate collagen in the GAG solution as collagen addition may alter the fiber wall properties while collagen gelation inside the fiber lumen will add material properties to that initially fluid space. Fiber tensile tests are ongoing, and results will be reported.

Acknowledgements (Optional):