Ruthenium (II) polypyridyl compounds that undergo photoinduced ligand exchange have emerged recently as a unique solution to several challenges in the chemical biology field that has propelled their use in biological settings as molecular photocages and for photomediated drug delivery. Their low lying MLCT states are accessible via visible light irradiation which penetrates more deeply through complex tissue. Ru(II) MLCT states are red-shifted with a simple exchange of polypyridyl bidentate ligands, so compounds that respond rapidly to a wide range of input wavelengths can be readily generated. These photochemical attributes leave Ru(II)-based biomaterial crosslinkers well poised to expand the current library of organic photocleavable crosslinkers which are limited by their sensitivity to primarily high energy (UV) light and their challenging syntheses.<br/>This presentation will showcase our recent successes in the design and application of a series of visible light-responsive cytocompatible Ru-based crosslinkers for next-generation hydrogel photomodulation. Results will highlight the synthesis and characterization of two new Ru(II) compounds (RuXlinker) that undergo ligand exchange selectively under 617 nm and 530 nm irradiation. Designed as difunctional crosslinkers, RuXlinkers form stable hydrogels through step-growth polymerization with multifunctional poly(ethylene glycol) star polymers. When used in combination with industry standard <i>ortho</i>-nitrobenzyl-based crosslinkers, a series of orthogonally photocleavable crosslinkers enabled selective three-way control over material stiffness via irradiation with orthogonal wavelengths of light. All crosslinkers exhibited similarly high viability of encapsulated cells over 5 days of 3D culture, and degradation gave release of live cells for downstream single-cell analysis. With excellent photophysical characteristics and cytocompatibility, this new class of RuXlinkers are expected to shine a new light on the future of photoresponsive biomaterials.

Ruthenium polypyridyl complexes as visible light-cleavable crosslinkers for soft biomaterial modulation

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.