M. Hirtz, A. M. Greiner, T. Landmann, M. Bastmeyer, H. Fuchs 

Adv. Mater. Interfaces 1 (2014) 1300129

We demonstrate the generation of multi-component spot microarrays by blotting different ink solutions via quill-like pens. The obtained arrays are immobilized by click-chemistry in form of the copper(I)-catalyzed azide-alkyne cycloaddition and remain stable against washing and immersion in aqueous solution. The average spot radius ranges from 10 to 20 μm and is about an order of magnitude smaller than in currently commercially applied arraying techniques, effectively bridging the gap to high resolution methods as dip-pen nanolithography and polymer pen lithography. The use of the quill-like-pen-generated spot microarrays as binding assay is demonstrated by capturing of streptavidin from solution and by bioactive sandwich structures from neutravidin and biotin-labeled fibronectin. Thus, our multi-component spot microarrays have ideal dimensions and biochemical properties to accommodate (single) cells. Additionally, the building up of the cell-recruiting protein sandwich structure on top of the basic spot microarray allows for the highly selective adhesion of fibroblasts. This results then in ordered (single) cell arrays, demonstrating the bio-compatibility and high throughput of this multi-component spot microarray platform.