Diffusion-Patterned Multi-Component Supramolecular Gels Loaded with Gold Nanoparticles Direct Mesenchymal Stem Cell Growth and Differentiation

This article describes a new fabrication method using simple paper stamps to pattern gold nanoparticles (AuNPs) in a hybrid hydrogel, creating multi-domain gels in which different domains have different cell compatibilities. Soaking a paper stamp in AuCl3 solution, and placing it on top of the gel, allows diffusion of Au(III) from the paper into the gel to create a patterned domain within the gel in which AuNPs are formed, with spatial resolution on the millimeter length-scale. The gels combine a low-molecular-weight gelator (LMWG) that chemically enables the in situ AuNP patterning and offers mesenchymal stem cell (MSC) compatibility with a rheologically stiff polymer gelator. Only the AuNP-loaded domains support MSC proliferation on the multi-domain system, inducing cell spreading and promoting osteogenesis with a reproducible pattern. This simple approach therefore programs a soft supramolecular material, enabling it to achieve spatially-resolved biological outcomes, and may have applications in tissue engineering.