Automated Assay Optimization with Integrated Statistics and Smart Robotics

Abstract

The transition from manual to robotic high throughput screening (HTS) in the last few years has made it feasible to screen hundreds of thousands of chemical entities against a biological target in less than a month. This rate of HTS has increased the visibility of bottlenecks, one of which is assay optimization. In many organizations, experimental methods are generated by therapeutic teams associated with specific targets and passed on to the HTS group. The resulting assays frequently need to be further optimized to withstand the rigors and time frames inherent in robotic handling. Issues such as protein aggregation, ligand instability, and cellular viability are common variables in the optimization process. The availability of robotics capable of performing rapid random access tasks has made it possible to design optimization experiments that would be either very difficult or impossible for a person to carry out. Our approach to reducing the assay optimization bottleneck has been to unify the highly specific fields of statistics, biochemistry, and robotics. The product of these endeavors is a process we have named automated assay optimization (AAO). This has enabled us to determine final optimized assay conditions, which are often a composite of variables that we would not have arrived at by examining each variable independently. We have applied this approach to both radioligand binding and enzymatic assays and have realized benefits in both time and performance that we would not have predicted a priori. The fully developed AAO process encompasses the ability to download information to a robot and have liquid handling methods automatically created. This evolution in smart robotics has proven to be an invaluable tool for maintaining high-quality data in the context of increasing HTS demands.

Design and Implementation of High Throughput Screening Assays

“…Several commercial packages exist that integrate design of experiments and necessary liquid handling steps to conduct the experiments. A good example is automated assay optimization (AAO) developed by Beckman Coulter (Fullerton, CA) in collaboration with scientists from GlaxoSmithKline [32]. An example of the outcome of one assay improved in our lab using this methodology is shown in Fig.…”

“…5. The article by Taylor et al [32] describes examples of assay optimization through AAO for several types of targets and assay formats.…”

Design and Implementation of High-Throughput Screening Assays

“…Full-factorial or partial factorial designs can be planned using several available statistical packages (e.g., JMP, Statistica, and Design Expert) and automated hardware and software solutions are available for more complex combinations of assay constituents. The Dragonfly ® system from TTPLabTech is a non-contact dispenser designed specifically for optimization experiments while Beckman Coulter have continued to develop the SAGIAN™ SAMI ® software system for full automated assay optimization (AAO) on the Biomek series of liquid handlers [28].…”

Overcoming Obstacles in the Implementation of Factorial Design for Assay Optimization

“…[5][6][7] In this article we provide an overview of how FED can be applied to the assay development process with a cellular assay example. A cellular assay has been chosen as an example because they have been less commonly reported in the literature, and to demonstrate the broad applicability of the tool independent of programmable liquid-handling systems.…”