Skip to main content
2023 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.
Back

    Biomaterials

    Engineering Hydrogels to Assess the Impact of Matrix Stiffness on Extracellular Vesicle Production

    (C-91) Engineering Hydrogels to Assess the Impact of Matrix Stiffness on Extracellular Vesicle Production

    Friday, October 13, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row C - Poster # 91

      Presenting Author(s)

    • Josiah I. Garan (he/him/his)

      Undergraduate Researcher
      Harvey Mudd College
      Claremont, California, United States

      • Primary Investigator(s)

    • Steven Santana

      Iris and Howard Critchell Assistant Professor, Engineering Clinic Director
      Harvey Mudd College
      Claremont, California, United States

    Introduction::

    Extracellular vesicles (EVs) are cell-secreted nanoscale structures enclosed by a lipid bilayer. EVs contain and transport functional molecules such as nucleic acids, lipids, and proteins to recipient cells throughout living organisms. EVs are important mediators of cell-cell communication and afford opportunities for insight into cellular function in physiological and pathological states. Because of these features, EVs have attracted interest as potential biomarkers and therapeutics.


    Since EVs are produced by virtually all cell types, it is critical to understand the fundamental mechanisms of EV biogenesis. EV biogenesis is responsive to the extracellular microenvironment including mechanical, structural, and compositional cues. In this study, synthetic hydrogels are deployed to investigate the role played by stiffness in EV biogenesis. EVs are isolated from cells cultured on hydrogels spanning a range of cell-substrate stiffnesses overlapping with the properties of healthy neural tissues. Characterizing EV cargoes and composition provides initial clues as to their biogenesis in response to matrix properties.


     



    Materials and Methods::

    Hydrogels are formed using an established poly(ethylyene glocol)-based thiol-ene hydrogel. Hydrogels of unique moduli are engineered by tuning the crosslinking density. The modulus of each hydrogel is characterized using shear rheology on a TA Instruments Discovery Hybrid Rheometer (DHR3). The reported hydrogel properties are within the linear viscoelastic region (LVR). 


    U87-MG cells are cultured in standard tissue culture polystyrene (TCPS) flasks in EMEM (Eagle's minimum essential media) with 10% (v/v) fetal bovine serum and 1% (v/v) penicillin-streptomycin. TCPS is coated with each hydrogel. U87MG Cells are seeded on the surface of those hydrogels and cultured in each condition until 80% confluency is reached. Cells are then triple washed and cultured in serum-free media for one day. Subsequently, EVs are purified from the conditioned media. EV size characterization is completed using a Nanosight NS300.


     



    Results, Conclusions, and Discussions::
    Young's modulus was characterized for each hydrogel formulation in triplicate, as shown in Figure 1. The modulus is directly related to the crosslinking density within the hydrogel network. Our initial results show that our hydrogel system can exhibit a modulus range overlapping with the properties of neural tissues. To recapitulate the modulus of a broader range of in vivo tissues, hydrogels with lower moduli will also be designed. Future work includes utilizing hydrogels with a lower modulus as a cell culture substrate to interrogate the EVs produced in these systems to gain insight into EV biogenesis.


    Acknowledgements (Optional): : Thank you to our sources of funding: the National Science Foundation (Award #2233193), Harvey Mudd College Engineering Department, Fletcher Jones Fund, and Norman F. Sprague III Fund.

    References (Optional): :