# 3D in vitro model of skeletal muscle development using stiffening silk biomaterials

> **NIH NIH P20** · BOISE STATE UNIVERSITY · 2022 · $131,717

## Abstract

Hydrogels incorporating silk protein primed with bioactive peptides have been successfully used 
to study the cellular processes underlying differentiation of skeletal muscle. However, previous 
systems were limited due to their static nature – their mechanical properties are fixed. Recently, 
we demonstrated a new silk hydrogel crosslinked with tyramine-substituted silk fibroin that 
stiffened over time at controllable rates. The programmable stiffness of these hydrogels makes 
them attractive for modeling the changes in tissue-level stiffness that are associated with 
musculoskeletal development, or following injury. We will modify these hydrogels to incorporate 
decellularized muscle extracellular matrix (ECM), obtained through a recently established 
decellularization protocol. Our preliminary data suggest coupling ECM to our silk matrices can 
be used to further fine-tune the stiffening, enabling highly controllable and distinct mechanical 
and matrix protein gradients within the same gel, by spatially varying the amount and type of 
ECM mixed in with the silk precursors. A silk-ECM hydrogel has not previously been developed. 
Our central hypothesis is that dynamically stiffening hydrogels with highly tunable mechanical 
and biochemical characteristics can recapitulate key aspects of the myogenic environment more 
effectively than existing engineered systems, and as a result, will improve our understanding of 
the process to enable better control of the therapeutic potential of myogenically differentiating 
iPSCs for regenerating skeletal muscle. We will develop hydrogels as novel in vitro systems to 
explore the impacts of dynamic stiffness on myogenesis of iPSCs. We will test our hypothesis 
using two specific aims. The first aim will be to determine how evolving stiffness in 3D hydrogels 
impacts iPSC myogenesis. The second aim will be to develop a biochemically functionalized 
and mechanically dynamic silk-ECM hydrogel for generation of skeletal muscle from iPSCs. 
Completion of these aims will enhance our understanding of the regulators of skeletal muscle 
development and the impact of dynamic substrate stiffness and matrix composition on stem cell 
differentiation, with the ultimate goal of therapeutically targeting these mechanisms to 
regenerate skeletal muscle using stem cells. 3D hydrogels can be further used to investigate 
the processes that regulate development, aging, injury, and disease of skeletal muscle.

## Key facts

- **NIH application ID:** 10629500
- **Project number:** 5P20GM109095-09
- **Recipient organization:** BOISE STATE UNIVERSITY
- **Principal Investigator:** Sophia Katerina Theodossiou
- **Activity code:** P20 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $131,717
- **Award type:** 5
- **Project period:** 2022-06-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10629500

## Citation

> US National Institutes of Health, RePORTER application 10629500, 3D in vitro model of skeletal muscle development using stiffening silk biomaterials (5P20GM109095-09). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10629500. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*