Abstract
Multiplexed microarrays—where different biological probes are spatially encoded onto a surface into spots with micrometer-scale diameters—have facilitated the rapid advancement of “omics” research. Further miniaturization of feature diameters could increase the number of probes in a microarray, reduce the sample required for analysis, and decrease costs. Tip-based lithography (TBL) has gained popularity for patterning delicate, biologically active materials, but no versatile TBL-based multiplexing strategy has been devised. Here, we combine microfluidics, beam pen lithography, and photochemical surface reactions to create multiplexed arrays. For proof of concept, the thiol-ene reaction was optimized, and the reaction kinetics were analyzed. Subsequently, we created several patterns containing multiple fluorescent alkenes, where each pattern was designed to demonstrate a different capability of this instrument. This patterning strategy is a powerful approach to studying and optimizing organic reactions on surfaces and creating massively multiplexed arrays and, as such, could provide an entirely new approach for miniaturizing biochips or understanding interfacial reactivity.
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•Combining microfluidics and photochemistry solves the TBL multiplexing challenge•Organic surface kinetics derived in a single experiment•Ability to explore interfacial organic chemistry reactivity•Synergistic combination of surface chemistry and instrumentation
There is a pressing desire to reduce feature diameters in biological arrays, which would increase the number of probes on the surface and reduce the sample volume required for analysis. The challenge that precludes miniaturization in biochips is that most nanolithography methods require high-energy beams that would denature or destroy soft matter. Alternatively, tip-based lithography (TBL) uses arrays of nanoscopic tips to pattern reagents on a surface nondestructively, but no versatile multiplexing strategy has been developed. Here, we solve this long-standing problem in TBL by combining massively parallel beam pen arrays, microfluidics, and organic surface chemistry to create multiplexed arrays whose features have a diameter of ∼1 μm. The applications of this printing platform include the preparation of gene, protein, and glycan chips that can rapidly advance “omics” research as well as provide a new tool for probing interfacial reactivity.
Braunschweig and co-workers developed a printing tool that combines microfluidics, organic photochemistry, and massively parallel tip-based lithography. This instrument can create complex multiplexed patterns with ∼1 μm resolution or be used for rapidly determining the kinetics of organic reactions at interfaces. This flexible printing strategy could lead to the rapid advancement of “omics” research.
