R30 - Extracellular matrix biomaterials for localized adeno-associated viral gene therapy

Friday, October 10, 2025

10:00 AM - 11:00 AM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

Chloe Connolly

Undergraduate Researcher
University of Maryland College Park
Bel Air, Maryland, United States

Co-Author(s)

Yahya Cheema

Doctoral Research Candidate
University of Maryland - Fischell Department of Bioengineering
College Park, Maryland, United States
DC

Devorah Cahn

Faculty research assistant
University of Maryland, United States
Matthew T. Wolf, PhD

Stadtman Investigator
National Cancer Institute / National Institute of Health, United States

Last Author(s)

GD

Gregg Duncan, Ph.D.

Associate Professor
University of Maryland
Columbia, Maryland, United States

Introduction: : Genetic diseases are inherited diseases which currently affect about 1 in 10 individuals worldwide. Adeno-associated virus (AAV) is a viral gene vector employed in several clinical trials for genetic diseases. Despite this widespread use, AAV delivery efficiency and biodistribution still have many areas for improvement, as when systemically administered there is a risk for toxicity and therapy-inactivating immune responses. This study aims to develop a hydrogel which mimics the extracellular environment and can better deliver AAV to sites of disease. Prior work has examined the ability of the extracellular matrix (ECM) from decellularized tissues to serve as biological scaffolds to deliver regenerative therapies and promote tissue healing. AAV binds to ECM and it is anticipated AAV will be similarly retained in an ECM scaffold of decellularized hydrogels. Based on previous works which use synthetic biomaterials for local AAV delivery, it is expected that the duration of AAV transduction will be increased using controlled release from ECM biomaterials. In this project, we determined the diffusion behavior of AAV through ECM-based hydrogels and evaluated the release rate of AAV from these hydrogels. Future directions include evaluating transduction efficiency of ECM-encapsulated AAV in relevant cell types. Developing this biomaterial method of delivery for viral vectors will not only have a large impact on the community of those living with genetic disorders but can shape the future of biomaterial delivery for many different therapeutics.

Materials and

Methods: : Previous studies have shown that decellularized extracellular matrix (ECM) from porcine tissues can mimic the ECM environment. To develop the dECM-hydrogel, a 10 mg/mL dECM digest is created through pepsin digestion of porcine lung tissue powder, which is diluted and neutralized to be kept as a stock. To form the physiologically relevant ECM-based hydrogel model, the dECM digest is combined with 1x PBS, 10x PBS, and 1M NaOH on ice. To measure AAV diffusion within the ECM, lung dECM hydrogel is placed on a custom imaging chamber slide, and incubated at 37 degrees Celsius for 30 minutes to establish viscoelastic properties similar to that of native ECM. Then, AAV particles and/or nanoparticles as a control are inserted directly into the hydrogel. Videos are collected via confocal microscopy for each slide and MATLAB analysis is used to calculate average mean squared displacement. To evaluate release of AAV from ECM over time, 100 μL of pre-loaded hydrogels are plated in a 1 mL plastic syringe, incubated at 37 degrees Celsius for 30 minutes, and ejected into PBS. At distinct time points, a PBS sample is taken and analyzed via spectroscopy to determine the amount of released particles.

Results, Conclusions, and Discussions:: We observed the motion of AAV in the lung dECM hydrogel and consistent with past studies, found AAV do indeed bind to ECM. As expected, 20 nm NPs had a larger MSD value than 100 nm NPs due to their smaller size which mimics that of AAV. Comparing 20 nm NP diffusion to that of AAV, there was a clear difference with AAV having lower average motion. The average hydrogel pore size determined through multiple particle tracking remained consistent, confirming that varying MSD values were a result of interactions and not likely due to physical entrapment. This establishes that dECM hydrogels can act as a depot for controlled release of AAV viral vector capsids used in gene therapy delivery. Now that a proper seeding density of particles for controlled release has been determined, release rates will be evaluated to establish the viability of dECM hydrogels as a local AAV delivery platform. Based on the results so far, 20 nm NPs move at a faster average MSD than 100 nm NPs in lung dECM. The average hydrogel pore size determined through multiple particle tracking remained consistent, confirming that varying MSD values were a result of interactions and not formation inconsistencies. Furthermore, AAV is adherent to dECM hydrogels due to surface interactions, as shown through the lower MSD values in comparison to 20 nm nanoparticles with no surface interactions. It has been established that dECM hydrogels can accurately model the increased surface interactions in ECM which hinder or slow AAV viral vector capsids used in gene therapy delivery. Now that a proper seeding density of particles for controlled release has been determined, release rates can be established to model dECM hydrogels as a AAV gene therapy delivery platform.

Acknowledgements and/or References (Optional): : We acknowledge support from the UMD-NCI Partnership for Integrative Cancer Research and the National Science Foundation (CAREER Award 2047794).