To provide its assay customers with a solution to a common high-throughput screening problem, Pierce Biotechnology announced on May 17 that it has allied with Swiss biotechnology company Tecan to develop an HTS platform using Tecan’s fluorescence lifetime detection technology.
Under the terms of the agreement, the companies will co-market the platform. This collaboration will include sharing specific product information and support with one another, as well as co-promotion of each other’s technologies in sales and marketing literature. Financial terms of the deal were not disclosed.
Tecan, which is headquartered in Mannedorf, Switzerland, brings to the deal its ULTRA Evolution detection platform, a microplate detection system for conducting high-throughput screening assays. Having been on the market for two years, it is one of several Tecan detection instruments for applications ranging from DNA and protein arrays to ELISA to biochemical and cell-based assays.
Rockford, Ill.-based Pierce is a part of Perbio Science, a biochemicals division of Fisher Scientific. Pierce offers a variety of products and reagents spanning multiple applications in basic biological research, diagnostics and drug discovery, but the deal with Tecan specifically affects its business in the area of protein profiling and assay development for drug discovery.
According to a company representative, the move is intended to spruce up Pierce’s biochemical assay platforms for investigating proteins involved in complex disease states — specifically, proteins such as kinases, proteases, and phosphatases.
The initial target of the new assay platform would be existing Pierce customers in pharma and drug discovery who have had trouble getting reliable data from drug candidate screens because the compound being screened autofluoresces at or near the same wavelength as the types of fluorescent probes commonly used in such assays, thereby interfering with the signal (or lack thereof).
“The potential of the [fluorescence lifetime] technology is to reduce false positive or false negative results from screening campaigns by being robust against autofluorescence,” said Siegfried Sasshofer, product group manager at Tecan. “Normally you have a lot of background if you’re using fluorophores in the UV range, and there are lots of them in that range,” Sasshofer said. “You get a lot of fluorescence from the compounds, or if you’re doing cell-based assays, you have a lot of proteins in there … that show massive autofluorescence.”
The idea would be for pharma companies to revisit promising compounds that have been previously looked at or have gone completely unstudied because they are highly autofluorescent and therefore are sitting around unproven in chemical libraries, Sasshofer added.
“On average, about ten percent of compounds that are screened in normal campaigns show massive autofluorescence, and are hard to evaluate using normal assays to find out whether they are positive or negative in a screen,” he said.
Fluorescence lifetime imaging or sensing involves using instrumentation that can discern how long a fluorophore probe, following excitation, fluoresces — typically on the order of nano- or picoseconds. It is frequently used in laboratory microscopy as a way to investigate complex protein dynamics, but as the technique has matured, it has found its way into higher-throughput fluorescence detection instruments, such as the ULTRA Evolution.
The reason it is ideal for screening autofluorescent compounds is that even if a fluorophore fluoresces at a similar wavelength to an autofluorescent compound, the duration of the fluorophore’s signal is dynamic, while that of the autofluorescent compound is static.
“We can completely eliminate this autofluorescence signal because we are measuring the difference in the lifetimes of bound and unbound, and the lifetime of the autofluorescent compounds will not change,” Sasshofer said. This difference is small, but can be detected using current lasers and photodetectors.
The ULTRA Evolution’s fluorescence lifetime option uses two ultra-fast pulsed lasers at 440 and 635 nm to irradiate samples, and a high-speed photon-counting photomultiplier tube to detect photons emanating from the sample. The instrument is also capable of performing a variety of other measurements, such as fluorescence polarization, intensity, and resonance energy transfer.
Assays for kinases, proteases, and phosphatases are all biochemical-based, and while Pierce offers a limited amount of cell-based assay tools — its series of CellScreen well-plates for cell-based assays being one of them — the partnership may in fact increase its capabilities in this area, as well, since the ULTRA Evolution is equipped for such purposes.
“Fluorescence lifetime as a technology is applicable to cell-based assays,” Sasshofer said. “The ULTRA Evolution is currently used for cell-based assays [by our customers] because it measures from the top as well as from the bottom, so if you have adherent cells on the bottom of the well, they can be measured with the best sensitivity from the bottom.”
“In addition, the ULTRA provides a special autofocus system that focuses into the layer of cells growing in the bottom of the well,” he added.
According to Sasshofer, the deal also marks Tecan’s first major foray into a full assay platform, as it has traditionally been focused primarily on instrumentation, as well as some associated consumables and reagents. In fact, Pierce was one of Tecan’s first customers, he said, having purchased instruments for its analytical laboratory.
A Pierce representative declined to name specific existing customers that might benefit from the new assay platform, but did say that the customer base comprised three major segments: Major pharma, clinical diagnostics companies, and academia.
“What we hope this solves is allowing pharmaceutical companies to look at those compounds that have been previously unstudied, and to therefore unlock potential new revenues and new drugs and bring those to market,” Sasshofer said.