Conjugated Polymer-Functionalized Stretchable Supramolecular Hydrogels to Monitor and Control Cellular Behavior

Natural extracellular matrix is formed by the assembly of small molecules and macromolecules into a hydrogel-like network that can mechanically support cells and involve in cellular processes. Here, we developed a fluorescent supramolecular hydrogel based on a conjugated oligomer OFBTCO₂Na, which facilitated noncovalent assembly through hydrophobic interactions and hydrogen bonds in a molecular scale. The generated dense three-dimensional network endows the supramolecular hydrogel with stretchability and stability. Furthermore, fluorescent OFBTCO₂Na in hydrogel acted as a donor, which can excite the acceptor dyes on cells encapsulated in hydrogel via the Förster resonance energy transfer (FRET) mechanism. Investigating the fluorescence signal responsiveness of hydrogel to dynamic mechanical stretching well reflected that enhanced stretching dictated the extent of connection between the cell and matrix, which enables effective FRET at a molecular level and allow spatiotemporally monitoring cell-matrix interactions at the three-dimensional network. Importantly, cells can sense stretch forces by their connection with a hydrogel matrix. The dynamic cell-matrix interaction can be conveniently employed to formulate cell morphology. Therefore, the fluorescent supramolecular hydrogel offers a suitable culture platform not only to investigate cell interactions on interfaces but also to regulate cell behavior at interfaces.