Sensing Cell Proliferation in 3D Culture With a Luminescent Hydrogel.

A vinyl-functionalized tetraphenylethylene derivative (OA-TPE) with aggregation-induced emission (AIE) was synthesized and incorporated into a poly(ethylene glycol) diacrylate (PEGDA) hydrogel by photopolymerization. OA-TPE emission increased with medium viscosity (log-log linear regression, R2 = 0.9861). A 21 wt% PEGDA hydrogel containing 2-μM OA-TPE supported the proliferation of encapsulated L929 mouse fibroblasts over 10 days. Between Day 1 and Day 10, the storage modulus (G') decreased from approximately 3638 to 2379 Pa, the loss modulus (G″) decreased from approximately 177 to 73 Pa, and fluorescence intensity decreased from 6237 to 4365 a.u. Fluorescence intensity was linearly associated with G' and G″ (R2 = 0.9878 and 0.9890, respectively). These data establish a proof-of-concept relationship among cell growth, hydrogel mechanics, and AIE emission in 3D culture. The method is indirect: A 10-day cell-free stability control, matrix-specific DNA recovery, and interference by pH, reactive oxygen species, or metabolites were not independently quantified, so the fluorescence decrease should not yet be interpreted as a cell-specific or fully quantitative proliferation signal.