Cell-derived lactate triggers local hydrogelation and phenotype remodelling.

Cell-derived lactate induces rapid, localized hydrogel formation with up to 5 kPa stiffness in tumour models, enabling spatial control of matrix remodelling.

• Why it matters: Understanding how tumour metabolism influences the surrounding matrix is crucial for insights into tumour progression and invasion, yet methods to harness metabolic signals for matrix engineering are limited.
• What they did: The study used phenol-functionalised alginate that remains soluble until oxidized by lactate oxidase, producing hydrogen peroxide to crosslink phenols via horseradish peroxidase, forming hydrogels within minutes in tumour spheroids.
• The result: Lactate-triggered hydrogelation created confined, gradient-rich matrices that modulate cellular behaviour, reducing proliferation and promoting migration, thus offering a platform to study tumour-matrix interactions.