Poster C1 - Incorporation of DAMPs within Collagen Based Hydrogels and its Effects on Mechanical Properties

Friday, October 25, 2024

10:00 AM - 11:00 AM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Ope Sanyaolu

Undergraduate Student
The University of Texas at San Antonio
San Antonio , Texas, United States

Co-Author(s)

VG

Victoria Garza, BS

Graduate Student
The University of Texas at San Antonio, United States
TG

Teja Guda, PhD

Jacobson Distinguished Professor of Innovation and Entrepreneurship
The University of Texas at San Antonio, United States

Primary Investigator(s)

Alisa Isaac, PhD (she/her/hers)

SABER IRACDA Post-Doctoral Scholar
The University of Texas Health Science Center
San Antonio, Texas, United States

Introduction: Collagen hydrogels are widely used in the field of biomaterials and tissue engineering. Although collagen on its own demonstrates fantastic biocompatibility, our recent work includes incorporating damage-associated molecular patterns (DAMPs) into collagen hydrogels to create a cell-responsive material for tissue regeneration. DAMPs are molecules expressed on damaged tissue or released by damaged cells to facilitate an immune response in a sterile environment that can be leveraged to encourage tissue repair. A DAMP of interest for this project is damaged collagen, and it has yet to be incorporated into hydrogel-based biomaterials. Here, we incorporate collagen-derived DAMPs into collagen I-based hydrogels and determine the effects of incorporation on the hydrogel's mechanical properties. Specifically, we measured the DAMP’s effects on storage modulus, crosslinking properties, and the polymer network of the collagen gel.

Materials and

Methods: To assess the impact that the incorporation of collagen-derived DAMPs has on the collagen hydrogel network, various gels were fabricated utilizing various v/v % of DAMPs (0%, 10%, 20%, and 30%) in a collagen hydrogel. To determine the storage moduli of DAMP-incorporated collagen gels, ElastoSens Bio (Rheolution) was utilized. Storage modulus was measured every 3 seconds for a duration of 90 seconds according to the manufacturer’s stiff material settings. Gel fraction and degree of swelling were determined by measuring the dry weight (Wd), swollen weight (Ws), and dried equilibrium weight (We) for all gel compositions. The following equations were utilized to calculate gel fraction percentage and degree of swelling. Gel fraction (%) = (We/Wd)*100. Degree of swelling = (Ws-Wd)/Wd.

Results, Conclusions, and Discussions: When evaluating storage moduli of DAMP-incorporated hydrogels, no changes were observed among all formulations (figure 1A). However, changes in gel fraction and degree of swelling were observed as DAMP concentration increased. Gel fraction, the fraction of the total initial gel that is incorporated within the hydrogel network and not part of the soluble fraction, increased with an increase in DAMP concentration, as shown in Figure 1B. Although not statistically significant, this suggests that DAMPs are part of the hydrogel network and are able to be crosslinked with undamaged collagen to form cross-linkable hydrogel networks. Degree of swelling, the relative amount of swelling observed after hydrogels were incubated in water overnight, was also increased with an increase in DAMP concentration (figure 1C). As the gel fraction data suggests that DAMPs may be incorporated into the hydrogel network, a similar observation is inferred from the degree of swelling data. The data suggests that the DAMP incorporation may increase the mesh size of the hydrogel network by occupying sites of collagen binding and, therefore, a looser polymer network. Overall, our data suggests that collagen-based DAMPs can successfully be incorporated into collagen-based hydrogels but may change hydrogel properties such as gel fraction and degree of swelling. Our future work includes evaluating mechanisms of crosslinking and also the changes in cell response to DAMP-incorporated hydrogels.

Acknowledgements (Optional): This work is supported by The University of Texas System Trauma Research and Combat Casualty Care Collaborative (175143).