Experiences in implementing uHTS--cutting edge technology meets the real world.

Driven by growing corporate compound files, the demands of target biology, and attempts to cut cost, the number of solutions to HTS has spiralled. In quick succession new assay technologies and screening platforms are appearing on the market, with the promise of screening faster than ever in low volume high density formats whilst providing high quality data. Within this world of rapid change, Pfizer has applied cutting edge technology to HTS by introducing screening in 1 microl formats utilising single molecule detection technology. Instead of resource intensive in-house development, Pfizer entered into a collaboration with Evotec OAI / Evotec Technologies and introduced their Mark-II EVOscreen platform. In this article we will outline the benefits of the approach taken at Pfizer, Sandwich, and introduce the Mark-II EVOscreen platform, illustrating the potential but also possible pitfalls of HTS miniaturisation.

A modular, fully integrated ultra-high-throughput screening system based on confocal fluorescence analysis techniques.

The rapid increase in size of compound libraries, as well as new targets emerging from the Human Genome Project, require progress in ultra-high-throughput screening (uHTS) systems. In a joint effort with scientists and engineers from the biotech and the pharmaceutical industry, a modular, fully integrated system for miniaturized uHTS was developed. The goal was to achieve high data quality in small assay volumes (1-4 microL) combined with reliable and unattended operation. Two new confocal fluorescence readers have been designed. One of the instruments is a 4-channel confocal fluorescence reader, measuring with 4 objectives in parallel. The fluorescence readout is based on single-molecule detection methods, allowing high sensitivity at low tracer concentrations and delivering an information-rich output. The other instrument is a confocal fluorescence imaging reader, where the images are analyzed in terms of generic patterns and quantified in units of intensity per pixel. Both readers are spanning the application range from assays with isolated targets in homogenous solution or membrane vesicle-based assays (4-channel reader) to cell-based assays (imaging reader). Results from a comprehensive test on these assay types demonstrate the high quality and robustness of this screening system.