Immunoassays have been widely adopted for analysis and quantification of low concentration proteins. The immunoassay is selective and sensitive; however, its utility has been limited in high-throughput systems due to a cumbersome process involving multiple incubation and wash steps.
AlphaLISA® was specifically designed to overcome the challenges of traditional enzyme-linked immunosorbent assays (ELISA) and to provide opportunities for high-throughput automation. Although microplate-based automation has yielded some success, it failed to meet the requirement of continuous automation for high-throughput (HT) applications.
The ideal system should provide: continuous automation, reproducible and rapid analysis of biological samples, easy setup and use, potential for broad deployment, and cost savings per data point. To address these needs, Douglas Scientific has developed modules that optimize the Array Tape™ platform for automated inline homogenous ELISA processing.
Array Tape is ideal for high-throughput nonwash homogenous ELISA assays. Recently, PerkinElmer developed such assays, founded on an amplified luminescent proximity, or AlphaScreen® assay. The fundamental principle rests on the use of oxygen channeling chemistry for ELISA analysis, commonly known as AlphaLISA. Based on a published report from PerkinElmer, almost any standard sandwich ELISA can be converted to AlphaLISA, thus providing opportunity to deploy Array Tape for inline high-throughput automation.
In the AlphaLISA assay, acceptor and donor beads are coated with hydrogel to provide a functional group for bioconjugation. Streptavidin-coated donor beads bind with a biotinylated anti-analyte antibody while another anti-analyte antibody is conjugated to the acceptor beads. In the presence of the analyte, the biomolecular reaction brings the beads into close proximity. The excitation of the donor beads provokes the release of singlet oxygen molecules that trigger a cascade of energy transfer in the acceptor beads, resulting in a sharp peak of light emission at 615 nm.
In response to the high-throughput screening needs of protein chemistry, the Array Tape platform from Douglas Scientific presents a highly effective and efficient inline automation solution for laboratory processes. This paper describes performing AlphaLISA assays such as TNF-α, IgG, and insulin from PerkinElmer using Array Tape and detection system specially developed for AlphaLISA assays.