Suspension Bead Arrays
Researchers at the KTH-Royal Institute of Technology, Albanova University Centre in Stockholm, have moved away from 2-D planar microarray technology and developed a suspension bead array approach to microtiter-plate-based qualitative proteomics.
Part of the Swedish Human Proteome Resource (HPR) program that generates the Human Protein Atlas resource, the research group, headed by Peter Nilsson, Ph.D., has been set up to develop methods for a systematic exploration of the human plasma proteome using array-based antibody proteomics.
“The technology for using antibodies on color-coded beads is available commercially and by optimizing parameters to ensure reproducibility, high sensitivity, and low background noise, we have developed an approach that can multiplex in two dimensions both in terms of antibodies and samples,” Dr. Nilsson explained. “Assays presently involving up to 96 antibodies profiling 96 samples can be carried out in a single run, detecting proteins down to lower pg/mL levels.”
The main advantage of the approach, in addition to the massive amount of data being generated, is the ability to use whole, labeled samples. “We take plasma samples and carry out direct biotinylation of the whole sample and then, without removing excess biotin, we can interrogate the sample using up to about 100 antibodies. Unlike sandwich assays, which although quantitative, have an upper limit of about 30 antibodies, our technology is only limited by the number of color-coded beads,” Dr. Nilsson said.
The main objective of the HPR center is to produce specific antibodies to human target proteins using a high-throughput production method that involves the cloning and protein expression of protein epitope signature tags. After purification, the antibodies are used to study expression profiles in cells and tissues and for functional analysis of the corresponding proteins in a wide range of platforms. The KTH site in Stockholm is responsible for generating and validating high-quality monospecific antibodies and performing immunofluorescence analyses.