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    Biomaterials

    Hydrolytically Degradable Granular Hydrogels for Tissue Engineering

    (C-94) Hydrolytically Degradable Granular Hydrogels for Tissue Engineering

    Friday, October 13, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row C - Poster # 94

      Presenting Author(s)

    • NK

      Nikki Kulkarni

      Undergraduate Researcher
      Purdue University - West Lafayette
      West Lafayette, Indiana, United States

      • Primary Investigator(s)

    • Taimoor H. Qazi

      Assistant Professor
      Purdue University, United States

    Introduction:: Biomaterials with tunable degradability to optimize drug delivery and create space for new tissue growth are becoming increasingly necessary for tissue engineering applications. Granular hydrogels are an emerging class of biomaterials with inherent porosity and injectability that have proven to be superior in terms of promoting cell growth as compared to non-porous bulk hydrogels [1]. However, granular hydrogels are predominantly made with covalently crosslinked microgels that show long-term stability, potentially restricting tissue growth and maturation and creating a need for degradable systems. In this study, we fabricated photocurable microgels with hydrolyzable crosslinks to develop granular hydrogels with tunable degradation rates.

    Materials and Methods:: Norbornene modified hyaluronic acid (Nor-HA) and a flow-focusing microfluidics approach were used to create spherical polymer droplets that were crosslinked into 100-150 μm microgels. Degradable polymer was synthesized by reacting HA with carbic anhydride (Nor-HACA)[2]. Fluorescent FITC-dextran was encapsulated within the microgels to investigate release and a separate fluorescent rhodamine thiol molecule was covalently attached to track microgel degradation (Fig. 1a). FITC-dextran release was tracked by characterizing the supernatant over time using a plate reader and morphological degradation was analyzed using fluorescence microscopy. Shear rheology was performed to characterize changes in mechanical properties.

    Results, Conclusions, and Discussions:: The influence of polymer concentration on microgel degradation was investigated for degradable Nor-HACA and non-degradable Nor-HA. Nor-HA microgels were highly stable, whereas Nor-HACA microgel degradation was inversely correlated to polymer concentration over a 14-day study. Release of the FITC - Dextran by day 14 in 4% Nor-HACA (w/v)  was more efficient (~3 a.u.) than 4% Nor-HA (~0.5 a.u.). Storage moduli of Nor-HA microgels show no significant difference over time (p-value = 0.83) while those of Nor-HACA microgels show significant difference, indicating polymer network degradation (p-value = 0.0000030).Our results describing encapsulated molecule release, microgel morphology, and changes in hydrogel mechanical properties expand the biomaterial design space for creating granular hydrogels with tunable degradability for potentially broad applicability in tissue engineering applications.



    Acknowledgements (Optional): :

    References (Optional): :

    [1] Daly et al. Nature Reviews Materials, 5(1), 20–43, 2019.


    [2] Galarraga et al. Biomacromolecules, 24 (1), 413–425, 2022.