The emergence of combinatorial chemistries and the increased discovery of natural compounds have led
to the production of expansive libraries of drug candidates and vast numbers of compounds with
potentially interesting biological activities. Despite broad interest in high throughput screening (HTS) 河南省人民医院妇科郭玉琪
across varied fields of biological research, there has not been an increase in accessible HTS technologies.
Here, we present a simple microarray sandwich system suitable for screening chemical libraries in cellbased
assays at the benchtop. The microarray platform delivers chemical compounds to isolated cell
cultures by ‘sandwiching’ chemical-laden arrayed posts with cell-seeded microwells. In this way, an
array of sealed cell-based assays was generated without cross-contamination between neighbouring
assays. After chemical exposure, cell viability was analyzed by fluorescence detection of cell viability
assays on a per microwell basis using a standard microarray scanner. We demonstrate the efficacy of the
system by generating four hits from toxicology screens towards MCF-7 human breast cancer cells. Three
of the hits were identified in a combinatorial screen of a library of natural compounds in combination
with verapamil, a P-glycoprotein inhibitor. A fourth hit, 9-methoxy-camptothecin, was identified by
screening the natural compound library in the absence of verapamil. The method developed here
miniaturizes existing HTS systems and enables the screening of a wide array of individual or combinatorial
libraries in a reproducible and scalable manner.We anticipate broad application of such a system as
it is amenable to combinatorial drug screening in a simple, robust and portable platform.