High-throughput cellular microarray platforms: applications in drug discovery, toxicology and stem cell research

Abstract

Cellular microarrays are powerful experimental tools for high-throughput screening of large numbers of test samples. Miniaturization increases assay throughput while reducing reagent consumption and the number of cells required, making these systems attractive for a wide range of assays in drug discovery, toxicology, stem cell research and potentially therapy. Here, we provide an overview of the emerging technologies that can be used to generate cellular microarrays, and we highlight recent significant advances in the field. This emerging and multidisciplinary approach offers new opportunities for the design and control of stem cells in tissue engineering and cellular therapies and promises to expedite drug discovery in the biotechnology and pharmaceutical industries.

Figure 1

Schematic illustration of a high-throughput 3D cellular microarray platform. (a) Preparation of a 3D cellular microarray. Cells are directly spotted on functionalized glass slides using a microarray spotter. Cell encapsulation is the result of alginate gelation mediated by the presence of Ba²⁺ ions (see insert). Positively charged poly-l-lysine promotes attachment of the negatively charged polysaccharide constituent of alginate upon gelation, keeping each spot in its location. PS-MA: poly(styrene-co-maleic anhydride). (b) Use of a cellular microarray for high-throughput toxicology assays. The platform shown in (a) can be used for direct testing of compound toxicity or for evaluating toxicity of P450-generated metabolites, as illustrated in the shown array. Dose–response curves are obtained from fluorescent staining of live cells, and IC50 values can be determined for each compound or for P450-generated metabolites (adapted, with permission, from Ref. [29]).

Figure 2

Factors affecting stem cell fate in the stem cell niche. These include physical cues, such as matrix elasticity and topography, cell–cell and cell–ECM interactions and soluble factors (e.g. growth factors and small molecules) that synergistically support cell growth and differentiation.

Figure 3

Schematic representation of a microwell platform for controlling the size of cellular aggregates. (a) Cross section of a microwell platform. (b) the process of creating cellular aggregates. (i) PDMS is cured on a silicon master to produce microwell-patterned surfaces. (ii) Surfaces are treated with fibronectin and seeded with mouse fibroblasts, which grow into a monolayer. (iii) The confluent monolayer is then inactivated and human ES cells are seeded inside the microwells, where they form cellular aggregates Adapted, with permission, from Ref. [59].