W24 - Design of Auxetic 3D-Printed dECM-Enriched GelMA/PEGDA Scaffolds for Cardiac Tissue Regeneration

Friday, October 10, 2025

10:00 AM - 11:00 AM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

Cecilia Fetterolf

Undergraduate Student
University of Virginia
Leesburg, Virginia, United States

Co-Author(s)

Chloe Hincher

Graduate Student
North Carolina State University
Raleigh, North Carolina, United States
MK

Mahmud Khan

Graduate Student
North Carolina State University, United States

Last Author(s)

RS

Rohan Shirwaiker

Professor
Edward P. Fitts Department of Industrial & Systems Engineering, United States

Primary Investigator(s)

Donald Freytes

Associate Professor
NCSU/UNC Lampe Joint Department of Biomedical Engineering
Raleigh, North Carolina, United States

Introduction: : Myocardial infarction (MI) is a major contributor to global morbidity, resulting in irreversible damage through cardiomyocyte loss, reduced cardiac output, and long-term dysfunction. Current therapies include the use of thrombolytics, bypass surgery, and electrical assist devices, focused on primarily alleviating acute symptoms. While these therapies address symptoms, they are unable to restore or mimic native myocardial function.

Consequently, cardiac regeneration remains a crucial therapeutic target for tissue engineering. Hydrogels and cardiac patches have shown promise in supporting cellular activity and structural integration; however, no material has fully and successfully replicated the complex deformation and anisotropic properties essential to myocardial mechanics.

To this end, this study will investigate the formulation of a novel combination hydrogel, consisting of GelMA (gelatin methacrylate), cardiac tissue-derived decellularized extracellular matrix (dECM), and PEGDA (polyethylene glycol diacrylate), as a biologically relevant tissue construct.
Furthermore, this work will explore 3D-printing of this material as an auxetic scaffold to recapitulate the structural and mechanical properties of cardiac tissue characterized by a negative Poisson’s ratio. Mechanical testing, including swelling ratio and compressive strength, will be assessed throughout the project. Simultaneously, cell compatibility will be evaluated. Together, these metrics will allow for preliminary investigation into material behavior and translational potential.

Materials and

Methods: : To formulate the scaffolding biomaterial, tissue from porcine right ventricle was first decellularized utilizing a standard procedure consisting of hyper/hypotonic rinses, enzymatic cellular removal, membrane solubilization, and DNA degradation. Remaining double stranded DNA (dsDNA) was then quantified, ensuring purity of the remaining dECM (Figure 1).

Following this, the obtained dECM at concentrations of 1, 3, 5, and 10% was combined with 5% GelMA and varying concentrations of PEGDA (5, 10, and 15%). These components, selected for biochemical cues, tunability, and mechanical strength, respectively, were combined with periodic agitation during incubation in a buffer solution with Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) photo initiator.

The solution was then UV cured for 10 seconds in small cylindrical samples with a 5 mm radius and 2.5 mm height, allowing for basic property investigation. Swelling ratio was calculated by dividing the prepared weight, after material equilibration for an hour following preparation, by the lyophilized weight. Following this, compressive testing was performed and a compressive modulus calculated, indicating sample strength. Simultaneously, neonatal human dermal fibroblast cells (HDFns), utilized for their availability and resilience in this preliminary study, were seeded on top of each gel sample. After 48-72 hours, an MTT assay was performed, providing qualitative data on cell metabolism and viability. These metrics were utilized to investigate the optimum concentration of each gel component.

Following preliminary characterization, a LumenX DLP printer was utilized to print a scaffold in a re-entrant honeycomb auxetic design, cited frequently in literature for tissue replication qualities, including a negative Poisson’s ratio.

Results, Conclusions, and Discussions:: The decellularization process left an average of 14% of the original dsDNA compared to the native tissue from the same source. Increased concentration of dECM resulted in a lower swelling ratio, indicating a more stable hydrogel (Figure 2A). Compression testing showed that the compressive modulus of each gel sample increased with higher dECM concentrations. (Figure 2B). Again, this trend highlighted increased mechanical strength. Similarly, when comparing cell viability, dECM concentrations of 3, 5, and 10% had a significant increase in cell viability, as compared to the cell control (Figure 2C). Of note, the 10% dECM failed to gel. As such, dECM concentrations of 3 and 5% were selected for further evaluation with varying PEGDA concentrations.

PEGDA concentrations, chosen for their prevalence in literature, were tested in combination with GelMA and dECM. As hypothesized, increasing PEGDA concentration led to a decrease in swelling ratio, indicating enhanced mechanical strength (Figure 2D). Compression testing is ongoing; preliminary results show high variability but an increasing trend in average compressive moduli with increasing concentrations (Figure 2E). In contrast, higher PEGDA concentrations were found to reduce overall cell viability compared to a cell-only control (Figure 2F).

Using the prepared gel solutions containing varying PEGDA concentrations, DLP printing reliably created a detailed re-entrant honeycomb auxetic pattern, with a brief light exposure time of 10 seconds (Figure 3). This contributes to the utility of this printing method to biologically relevant cardiac tissue constructs.

Further optimization is needed to confirm the behavior of the auxetic scaffold, as well as applicability to the cardiac environment. Dynamic mechanical evaluation, including tensile testing and cyclic loading, will contribute to a greater understanding of how an auxetic scaffold can replicate the complex behavior exhibited by cardiac tissue. Simultaneously, cell compatibility studies, including viability staining and additional metabolism assays, will be conducted using human stem cell-derived cardiomyocytes to ensure biological relevance. Together, these studies present a preliminary investigation into a novel composite hydrogel, designed for biomimicry and cell compatibility, and an auxetic scaffold that replicates the anisotropic properties of myocardial tissue to more precisely recreate the native cardiac environment.

Acknowledgements and/or References (Optional): :