Isothermal Titration Calorimetry
“The Auto-iTC300 is a powerful tool for small molecule biotherapeutics,” says Eric Reese, Ph.D., head of business development at Microcal, now part of GE Healthcare. According to Dr. Reese, an isothermal titration calorimetry system is used in Microcal instruments to study the binding of small molecules to larger macromolecules.
The Auto-iTC300 system is an upgraded version of the Auto-iTC200. It consists of a sensitive isothermal titration calorimeter combined with full automation for unattended operation. With the included software it is possible to program the device for a variety of experimental parameters.
“The platform is ideal for a high-throughput format. It can be used to measure binding affinity for small molecules in drug discovery programs as well as assist in designing innovative drug candidates.”
Isothermal calorimetry can also be used to study protein-metal, protein-protein, receptor-nucleic acid, antibody-antigen, protein-carbohydrate, and protein-lipid interactions.
Agilent Technologies is working with a number of industrial and academic clients, including Los Alamos National Laboratory and the UCLA School of Public Health, to speed up genomic workflow, reports Marc Beban, Ph.D., director, integrated systems and software marketing.
The company also has several initiatives under way in the agricultural biotechnology sector to automate sequencing of crop and pathogen genomes. The sequencing data can be used to discover favorable genetic traits that can then be inserted into crop plants either through conventional breeding or genetic engineering.
In the field of microbial detection, Agilent uses its platform to sequence genomes from single cells. This is an especially useful approach to gene mapping in hard-to-culture strains of bacteria and could lead to unique markers that could be integrated into new diagnostic probes. Because of the vast amount of DNA that must be screened, this project must be executed with a rapid screening methodology, Dr. Beban adds.
Agilent moved into automation of genomic workflow two years ago through the acquisition of Velocity 11. The process of large-scale sequencing feeds upon itself, as more and more genomes are sequenced the process becomes more automated, accelerating the rate of sequencing.
“We have a team of application scientists, including biologists and engineers that work with customers to build solutions adaptable to complex scientific problems,” said Nitin Sood, division manager, integrated systems and software marketing.
The SPRimager®II array reader is a label-free, SPR-based platform developed by GWC Technologies. Voula Kodoyianni, Ph.D., CSO, reports that the system “delivers a compelling combination of efficient throughput and experimental robustness.”
She says that the technology is among the most versatile of molecular detection systems, given that it is label free, monitors multiple interactions simultaneously, and acts independently of the chemistry of the molecules or the reactions that they may enter into.
“There is no need to modify the molecules with fluorescent or other tags that might compromise their function,” she adds. “Furthermore, and this is not generally appreciated, the technology provides real-time data, enabling the investigator to monitor the progress of binding without disturbing the molecular interaction.”
As is standard practice in such systems, the SPRimager II reads interactions occurring on gold-coated chips to which molecules may be covalently attached or bound through affinity interactions such as streptavidin-biotin complexes.
Producing the arrays is straightforward and can be done through hand-pipetting using the company’s SpotReady™ chips, or, for higher density arrays, with the aid of a robotic spotter using plain gold SPRchip™ substrates. Solutions containing analytes are washed through the flow cell of the reader over the arrayed molecules and molecular associations can be monitored as changes in reflectivity as a function of time.
GWC Technologies is collaborating with Lloyd Smith, Ph.D., professor in the department of chemistry at the University of Wisconsin, who has developed an amorphous carbon covering to protect the gold surface of the chip.
Conventional gold-coated chips are acknowledged to be fragile and can delaminate under harsh conditions such as with the use of strongly alkaline or acidic solutions. The amorphous carbon layering technology provides a much more robust surface and allows a wider variety of chip modifications to be performed, Dr. Kodoyianni says, including direct on-chip synthesis of oligonucleotides and other oligomeric biomolecules of interest. Such approaches dramatically reduce costs and increase efficiency of array fabrication.