Researchers can build the assays from scratch, but many choose to buy kits from assay providers. Microtiter plates that are precoated with an antibody of interest have been commercially available from several companies for a number of years. The researcher adds sample, detection antibody, and substrate to the wells with two wash steps required to perform the assay.
The new GE Healthcare Biotrak Easy ELISA technology is about making the process easier and saving hands-on time for the end-user, says Macdonald. In the new version, the microtiter plates include a prediluted standard curve and experimental wells that contain all the reagents necessary to conduct the assay. All the reagents are preformatted and lyophilized in 96-well plates. The researcher only needs to add sample and substrate to the wells. This new format results in time saving and increased precision, says Macdonald.
Another example of custom preformatted reagents is BD Biosciences (www.bdbiosciences.com) Lyoplate Technology, launched in September 2005. Lyophilization itself is not new, the key value is the quality and versatility of the proprietary matrix we are employing, notes Tony Ward, director of global strategic marketing for research cell analysis.
Custom microtiter plates that contain standardized and stable lyophilized reagents (Mabs, peptides, or cells) can be designed and engineered to order in just a few weeks. Benefits are simplified, ease-of-use, as well as potential reduction of error that can be associated with complex experimental designs.
Although the technology has broad applicability, one new example offered by BD is PhosFlow analysis, a flow cytometry-based technology employing phosphorylation-site specific antibodies and cell surface markers that allows activation state analysis of multiple proteins at single cell levels. Ward believes the technology has the potential to standardize clinical trials due to its ability to rapidly deliver customer specified kits.
Applied Biosystems (ABI; www.appliedbiosystems.com) offers customizable and preformatted 384-well microfluidic cards for real-time PCR. Customers can design their own TaqMan Low Density Arrays over the web by choosing from over 40,000 predesigned TaqMan Gene Expression Assays. ABI then manufactures the arrays with the chosen assays in the wells, explains Nico Tuason, product manager.
The microfluidic cards are used with ABIs 7900 HT real-time PCR system. According to Criss Walworth, product line director for gene expression, the TaqMan Arrays eliminate the need for liquid-handling robotics, since sample and reagents only need to be loaded into eight loading ports that each serve 48 wells. For studies done at multiple sites, the arrays offer additional advantages, according to Walworth, including highly reproducible and operator-independent results.
In December, the company expanded its offering of preselected, preformatted arrays to include the human G protein-coupled receptors panel, human protein kinase panel, mouse immune panel, human immune panel, and human endogenous controls panel.
Walworth says that ABI collaborated with pharmaceutical companies to choose the lists of targets that are included in the panels and that it was relatively easy to get agreement from the research community. Because the preformatted panels are offered as an inventory product, they can be ordered on demand. Another advantage is that they can eliminate the process of repeatedly designing and configuring assays.
People get hooked on convenience products, says Walworth. Sure they can do the work, but this makes it easier to do the actual experiment, notes Tuason.