# Hybrid Scaffolds Decouple Biochemical & Biophysical Regulation of Cell Phenotype

## TL;DR

A new biomaterial system allows separate control of stiffness and matrix composition to study how cells respond to changes in their environment.

## Contribution

This is the first system to independently control stiffness, composition, and 3D collagen architecture in hybrid scaffolds.

## Key findings

- Fibroblast morphology depends on scaffold composition and viscoelasticity.
- Collagen fiber patterning enhances breast cancer cell proliferation and invasion.
- Hybrid scaffolds enable combined control over biochemical and biophysical cell drivers.

## Abstract

The extracellular matrix changes dramatically during the progression of diseases like cancer. These complex, tissue‐specific changes are not adequately replicated by most current biomaterial disease models. This work demonstrates, for the first time, a biomaterial system allowing combined, independent control over stiffness, extracellular matrix composition and 3D collagen architecture. Defined hydrogel formulations are successfully perfused into ice‐templated collagen scaffolds, controlling the composition of these hybrid scaffolds at constant stiffness. The Young's moduli of these hybrid scaffolds can also be tuned independently of composition via chemical cross‐linking. Encapsulation of human dermal fibroblasts reveals that fibroblast morphology depends on hybrid scaffold composition and on viscoelasticity, highlighting the importance of a system that decouples biophysical from biochemical properties. Finally, these hybrid scaffolds are successfully applied to exert combined control over biochemical and biophysical drivers of cell growth and invasion, focusing on breast cancer as proof‐of‐concept. The results reveal that collagen fiber patterning enhances breast cancer cell proliferation, also directing the invasion of patient‐derived breast cancer cells. These hybrid scaffolds are therefore promising new tools for dissecting the diverse but complementary roles played by the extracellular matrix in regulating cell phenotype, in a range of healthcare applications.

Replicating tissue‐specific extracellular matrix is crucial for understanding its role in disease. This work demonstrates independent control over stiffness, composition and 3D collagen architecture using hybrid scaffolds: patterned collagen perfused with defined hydrogels. Tuning these properties reveals distinct influences of microscale viscoelasticity and fiber patterning on cell phenotype. This demonstrates hybrid scaffolds’ utility for probing matrix influences on disease progression.