Polymer chemistry

Biology

Biochemistry

Chondrocyte

Polymer

Alternative medicine

Organic chemistry

Anatomy

Self-healing hydrogels

Norbornene

In vitro

Osteoarthritis

Aggrecan

Medicine

Chemistry

Cell

Hyaluronic acid

Monomer

Articular cartilage

Biophysics

Chondrogenesis

Pathology

Nature Communications

3D microenvironmental parameters control cell behavior, but can be challenging to investigate over a wide range of conditions. Here, a combinatorial hydrogel platform is developed that uses light-mediated thiol-norbornene chemistry to encapsulate cells within hydrogels with biochemical gradients made by spatially varied light exposure. Specifically, mesenchymal stem cells are photoencapsulated in norbornene-modified hyaluronic acid hydrogels functionalized with gradients (0–5 mM) of peptides that mimic cell-cell or cell-matrix interactions, either as single or orthogonal gradients. Chondrogenesis varied spatially in these hydrogels based on the local biochemical formulation, as indicated by Sox9 and aggrecan expression levels. From 100 combinations investigated, discrete hydrogels are formulated and early gene expression and long-term cartilage-specific matrix production are assayed and found to be consistent with screening predictions. This platform is a scalable, high-throughput technique that enables the screening of the effects of multiple biochemical signals on 3D cell behavior.

Combinatorial hydrogels with biochemical gradients for screening 3D cellular microenvironments