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Biomaterials

Biomaterials - Poster Session E

Poster B5 - SYNTHESIS AND CHARACTERIZATION OF GELATIN METHACRYLATE CRYOGELS

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

Introduction:  Progress in the field of tissue engineering critically depends on the development of engineered biomaterials. Gelatin methacrylate (GelMA) cryogels are promising biomaterials for various tissue engineering applications due to their tunable properties, biocompatibility, and biodegradability. The objective of this work was to synthesize GelMAs under different conditions, such as various concentrations, and fully characterize their mechanical and transport properties and cytocompatibility.

Materials and

Methods:  GelMA was first synthesized by dissolving Type A porcine gelatin with Dulbecco’s phosphate buffered saline (DPBS), reacted with methacrylic anhydride (MA), and diluted with DPBS to stop the reaction. This mixture was dialyzed for 4 days to remove unreacted MA. The GelMA was lyophilized and dissolved at desired concentrations (1.0%, 1.5%, and 2.0%) in DI water. Radical initiators tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) were added to catalyze the radical polymerization of methacrylate groups. The mixture was immediately pipetted into their molds and placed into a -20°C freezer and thawed before use. Mechanical properties of the gels were determined using an Instron 3343 compression tester equipped with a 50-N load cell, and the storage and loss moduli were measured with oscillatory tests using a DHR2 rheometer at 1% strain. Microstructures of cryogels prepared with different concentrations were imaged using a scanning electron microscope (SEM). To determine cytocompatibility, cryogels with different concentrations were seeded with cells by placing lyophilized samples in a centrifuge tube with the suspension of MDA-MB-281 cells at different densities between 100,000 to 1,000,000 cells/ml and incubating to promote cells adhesion to the cryogel. The gels were then placed in a well plate containing culture media for 48 hours and subsequently imaged using fluorescence microscopy to observe cell attachment. After verifying the cells’ attachability to the cryogels, a cell viability assay was done using PrestoBlue cell viability reagent. The cryogels were incubated with PrestoBlue for 2 hours and the fluorescence was measured using a plate reader.

Results, Conclusions, and Discussions: 

Results: Compression testing of GelMA cryogels revealed the Young’s modulus increased systematically by increasing the concentration of dissolved GelMA as calculated from the slope of the linear region of the stress-strain curve falling between 0-15% as seen in Figure 1. The rheometric characterization done with a frequency sweep from 1-10 Hz measured the storage modulus at each concentration. These values increased from 304± 72 Pa at 1% to 779± 66 Pa at 1.5% and to 1684± 169 Pa at 2% concentration (Figure 2). The pores observed from SEM images at lower concentrations had less uniformity between pore shapes and thinner walls as compared to the higher concentrations where the pore walls were thicker and more structured. Cell seeding was observed using fluorescence microscopy after 48 hours of incubation and was confirmed to be successful using PrestoBlue to measure cell viability where there was higher fluorescence at greater cell concentrations as seen in Figure 4.

Discussion: The study shows that GelMA cryogels have tunable mechanical and structural properties, suitable for various tissue engineering applications. The increase in the GelMA concentration leads to more crosslinking in the cryogel which results in more organized and stiff pore structures. These more structured pores result in increased mechanical strength as seen in the increasing Young’s and storage moduli which could affect cellular interactions. Successful cell seeding observed though the fluorescence microscopy and cell viability assay confirms the biocompatibility of GelMA cryogels, highlighting their potential for customizable 3D tissue scaffolds in regenerative medicine and biomedical research.

Conclusions: The tunability of the GelMA cryogels provides the ability to modify the stiffness and pore size of the structure as desired to closely mimic different tissue types. This cryogel is a promising scaffold for research to mimic tissues such as bone and other microenvironments.

Acknowledgements (Optional):  Acknowledgments: Funding was provided by NSF grant 2140104.