Analyte-localization device for point-of-use processing of sub-millimetre areas on surfaces

We present a portable, simple-to-operate, point-of-use analyte surface localization device. We take advantage of a set of hydrodynamic design features and components that achieve passive analyte localization by means of a single vacuum input. The vacuum source can be supplied by mechanical or battery-operated vacuum sources that are portable and allow point-of-use operation in the absence of electricity. We discuss the governing hydrodynamic principle and design parameters in detail. In a case study, we demonstrate the applicability of our technology to successfully localize a solution of rhodamine on a polydimethylsiloxane (PDMS) substrate and produce sub-millimetre-sized spots via application of a mild vacuum pressure of less than 10 kPa. In addition, we demonstrate local staining of breast cancer cell blocks and on human breast cancer tissue sections.