Evaluation of Silk Inverse Opals for “Smart” Tissue Culture

[Image: see text] Visually tracking the subtle aspects of biological systems in real time during tissue culture remains challenging. Herein, we demonstrate the use of bioactive, cytocompatible, and biodegradable inverse opals from silk as a multifunctional substrate to transduce both the optical information and cells during tissue culture. We show that these substrates can visually track substrate degradation in various proteases during tissue digestion and protein deposition during the growth of mesenchymal stem cells. Uniquely, these substrates can be integrated in multiple steps of tissue culture for simple-to-use, visual, and quantitative detectors of bioactivity. These substrates can also be doped, demonstrated here with gold nanoparticles, to allow additional control of cell functions.