Authors:

Leia Schiltz

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About Paper:

Injectable biomaterials are attractive treatment strategies for tissue engineering applications because they allow minimally invasive delivery and facilitate the filling of unevenly shaped wounds. However, in synthetic biomaterial systems, it is challenging to simultaneously optimize several properties including porosity, mechanical stiffness, and injectability. For instance, traditional injectable hydrogels have low porosity that hinders cell invasion and tissue growth. The goal of this SURF project was to develop granular hydrogels with tunable stiffness and porosity for use in tissue repair. We used a photocurable norbornene-modified hyaluronic acid (Nor-HA) polymer at varying concentrations and degrees of crosslinking and characterized mechanical properties (e.g., elastic modulus) using a uniaxial compression test. Bulk Nor-HA hydrogels were fragmented via extrusion through syringe needles into microparticles, and the resulting polydisperse population was sorted using a strainer into small and large particle fractions. Unsorted and sorted particles were then assembled into granular hydrogels by vacuum filtration. Particle size was imaged using fluorescence microscopy and hydrogel porosity was visualized using confocal microscopy; results were quantified via ImageJ. We found that particle size and degree of packing significantly influence hydrogel porosity and rheological behavior. Rheological data indicates that the size and degree of packing also affect the shear strain response and the yield strain value, impacting the extrudability of the hydrogels. Overall, our findings suggest that granular hydrogels made with fragmented particles are promising biomaterials with properties to support tissue regeneration by providing more space and stability to promote cell growth.

Source:

Purdue University / 2023

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Co-authors:

Leia Schiltz