Spatial and Chemical Surface Guidance of NK Cell Cytotoxic Activity

Studying how different signaling pathways spatially integrate in cells requires selective manipulation and control of different transmembrane ligand–receptor pairs at the same time. This work explores a novel method for precisely arranging two arbitrarily chosen ligands on a micron-scale two-dimensional pattern. The approach is based on lithographic patterning of Au and TiO2 films, followed by their selective functionalization with Ni–nitrilotriacetic acid–histidine and biotin–avidin chemistries, respectively. The selectivity of chemical and biological functionalizations is demonstrated by X-ray photoelectron spectroscopy and immunofluorescence imaging, respectively. This approach is applied to produce the first type of bifunctional surfaces with controllably positioned ligands for activating the receptors of natural killer (NK) immune cells. NK cells were used as a model system to demonstrate the potency of the surface in guiding site-selective cell attachment and activation. Upon applying the suitable l...