This article is the seventh in a series of bi-weekly columns focusing on the area of "high-throughput biology," or new techniques for high-volume cell-based screening and imaging that biopharma is using to validate targets generated through genomics or proteomics, screen for toxicity, and replace other traditional assays. Links to previous columns in this series can be found below.
NEW YORK, March 8 (GenomeWeb News) - Recently, two companies in the cell-based assay field have signed technology collaborations with Becton Dickinson. TTP LabTech, of Cambridge, UK, signed an agreement in February for validation of BD Bioscience Clontech's Novel Flourescent Proteins on its Acumen Explorer instrument-part of the company's move to evolve the instrument to meet additional needs of its customers. Then, last week, Tranzyme Pharma of Research Triangle Park, NC, said it expanded an alliance with BD Technologies to develop high-throughput assays using the company's transfection technology.
TTP's Violet Venture
Violets have been springing up in TTP Labtech's R&D labs -- specifically, 405nm violet lasers, which the company has been testing out with its Acumen Explorer laser scanning cytometer for cell-based high content screening, company executives recently told GenomeWeb News.
The Acumen Explorer, which has been on the market for 18 months now, currently uses a 488 nm argon (blue-blue green) laser for excitation of fluorescent molecules used in cell-based assays. The instrument, which is based on a non-confocal optic system for high-speed scanning of objects in the bottom of microplate wells, also allows independent detection of four colors in a single well.
But the flexibility in excitation wavelengths has become "increasingly important," as users move into the high-content assay area, said Wayne Bowen, the company's chief scientific officer. In particular, it appears that beta lactamase assays can be more precisely read with the violet laser, Bowen said.
In addition to the violet laser, "We have in development a number of other excitation wavelengths," said Jas Sanghera, the company's commercial director. "With semiconductor lasers becoming more available in a whole range of spectra this is particularly an area that we are going to expand," he said. "We are talking about multiple excitation aspects of our instrument in the future."
This future version of the Acumen Explorer will enable users to switch between the two different lasers "at the switch of a button with the software," said Bowen.
On the detection side, the company is planning to stick to four colors -- "that's pretty much as far as most people want to take it, Sanghera said.
But the multiple excitation wavelengths could enable the Acumen explorer to evolve into a system with "up to eight channels of data collection," Bowen said, adding that this eight-channel readout "starts to get a bit scary in terms of the complexity of the assay and also in terms of the fluorochromes, so they are going to be required to meet that."
These developments segue with the collaboration with BD Biosciences Clontech in which TTP is developing validated protocols for BD's Novel Fluorescent Proteins on the Acumen Explorer. These proteins include DsRed, HcRed, AsRed, ZsGreen, AmCyan, ZsYellow, and monomeric AcGFP, and are to be used primarily for reporter gene analysis.
"We want to develop the product in tandem with the biology that's coming available, and that's what were looking to do with our collaboration that we've just announced with Becton Dickinson, and also with the emergence of new molecules, new fluorochromes," Bowen said.
The company has also recently launched an application for the Acumen Explorer that enables users to put microplates under an automated microscope to view the cells inside.
"We are starting to try to link the visualization aspects with scanning," Sanghera said.
These tweaks in the Acumen Explorer are the latest innovations in a laser scanning system that the company has been working on for over a decade. TTP Group, founded in 1987 as an engineering technology consultancy that worked on everything from lawnmowers and power tools to pharmaceutical automation, entered the field of pharmaceutical laser scanning in 1993, with the development of an instrument called Chemscan. This instrument uses laser scanning and fluorescence to detect microbial contamination in pharmaceutical compounds.
After the system proved itself to be more sensitive than current methods of microbial detection, TTP began to work with testers at Astra (now AstraZeneca) and Rhone-Poulenc Rhorer (now Aventis) to develop a system that applied this laser scanning technology to high throughput screening. This development process took over 3 years and cost over £5 million ($9.2 million), according to Sanghera.
Currently, the Acumen Explorer, which carries a pricetag of between £100,000 and £150,000, depending on whether the locator microscope and other features are attached, is able to scan a 20 x 20 micron area at the bottom of a wellplate with nearly the speed of a bulk reader, and can read up to 30,000 compounds per day.
"There isn't an imaging system on the market that offers [scanning the entire well] routinely at the resolution that the Acumen explorer does," Jas said.
About 25 of these units have been manufactured, and 15 are with major pharmaceuticals. The others are either leased to companies are being used by TTP for in-house screening services projects.
With the new additions to the system, however, the company is hoping to, well, really excite the market.
Tranzyme's "TV Dinner" Delivery Vectors
Tranzyme's deal with BD technologies, announced March 2, is an extension of a partnership that the two companies began in 2002 to develop high-throughput assays.
Under the agreement, BD has access to Tranzyme's TranzVector and Text gene delivery and expression technologies. Tranzvector is a lentivrial gene delivery system in which DNA is spliced into the lentivirus vector and then is delivered to the nucleus of a cell via that vector. Text, or Tranz Expression Technology, is a system that enables genes to be expressed in a mammalian cell.
"We create cell lines with multiple genes [transfected] into them and create permanent cell lines, and immortalize these cell lines," said Vipin Garg, the CEO of Tranzyme. "Once you've created such a cell line, it gives you a stable baseline."
The partners are using this technology along with BD's expertise in tissue culture and surfaces for cell-based assays, to develop a technology wherein "the gene delivery vector is immobilized" on a microplate, said Ram Ramabhadran, the company's senior vice president of R&D. The plates can be frozen, then can be unfrozen, like TV dinners, and cells can be placed in the wells. "Whatever cells you want-it could be hepatocytes or any other cell type that can be assayed, will get tranduced by the vectors," Ramabhadran said.
The system is not yet in beta testing, but Garg said that BD Biosciences Clontech is a potential beta tester. The company plans to have this gene delivery vectors in microplates ready for the market by late 2005 or early 2006.
BD, which is providing R&D funding, has the rights to market these or any other commercial products under the collaboration.
Other High-Throughput Biology Columns