Photo-patterned free-standing hydrogel microarrays for massively parallel protein analysis

Abstract

Microfluidic technologies have largely been realized within enclosed microchannels. While powerful, a principle limitation of closed-channel microfluidics is the difficulty for sample extraction and downstream processing. To address this limitation and expand the utility of microfluidic analytical separation tools, we developed an openchannel hydrogel architecture for rapid protein analysis. Designed for compatibility with slab-gel polyacrylamide gel electrophoresis (PAGE) reagents and instruments, we detail the development of free-standing polyacrylamide gel (<i>fs</i>PAG) microstructures supporting electrophoretic performance rivalling that of microfluidic platforms. Owing to its open architecture – the platform can be easily interfaced with automated robotic controllers and downstream processing (e.g., sample spotters, immunological probing, mass spectroscopy). The <i>fs</i>PAG devices are directly photopatterened atop of and covalently attached to planar polymer or glass surfaces. Due to the fast &lt; 1 hr design-prototype-test cycle – significantly faster than mold based fabrication techniques – rapid prototyping devices with fsPAG microstructures provides researchers a powerful tool for developing custom analytical assays. Leveraging the rapid prototyping benefits - we up-scale from a unit separation to an array of 96 concurrent fsPAGE assays in 10 min run time driven by one electrode pair. The <i>fs</i>PAGE platform is uniquely well-suited for massively parallelized proteomics, a major unrealized goal from bioanalytical technology.