EMD Millipore this week introduced a new technology platform to detect RNA expression in live cells.
Called SmartFlare RNA Detection Probes, the products enable users to generate "real-time, physiologically relevant" data with a single incubation step, and have a "wide range of capabilities" ranging from "simple, on-off" gene expression experiments to providing more quantitative answers, Victor Koong, SmartFlare product manager at EMD Millipore, told BioArray News.
Billerica, Mass.-based EMD Millipore is the life science division of the German chemical and pharmaceutical company Merck KgaA. The firm claims that its SmartFlare probes use inert nanoparticle technology to specifically detect native RNA. The probes are added to cell cultures and incubated overnight, and then RNA detection is then performed using any fluorescence detection platform. Once an experiment is complete, the non-toxic probes exit cells on their own, allowing researchers to perform subsequent downstream analyses on the same, unperturbed cells.
Koong said it is this ability to perform additional analysis on the same cells that makes the platform complementary to some multiplexing technologies, especially those that are used to monitor protein expression, including Luminex's bead-based assays.
"Luminex would definitely be complementary," he said.
Though researchers monitor gene expression changes using a variety of tools — including RNA-seq, whole-genome gene expression microarrays, and real-time PCR — Koong placed SmartFlare in the category of lower-multiplex applications.
"This is more competitive with RT-PCR, quantitative PCR, and RNA” fluorescence in situ hybridization, he said. "It's very different from the way they do it though, different in what type of data you are able to get," he said.
As EMD Millipore claimed in its statement, because SmartFlare probes allow researchers to work on live, not lysed, cells, the technology offers the ability to track changes in RNA dynamically, over time. The probes also enable analyses that can link gene expression profiles and phenotypes. The company also claims that SmartFlare probes can be used to sort cell types that are difficult to isolate, using biologically relevant intracellular RNA markers.
Koong said that the probes can be added to cell populations in plates, including 96-well plates and six-well plates, as well as flasks, but that there "isn't a requirement for what type of format you need; a lot of it is based on the user."
Researchers can use the probes to visualize RNA with microscopy or detect RNA with flow cytometry depending on the user's interest. Flow cytometry, for example, will provide customers with "relative quantitation, which a lot of people are looking for, and it will give you single-cell resolution of a gene of interest within your population," said Koong.
"Rather than doing something like RT-PCR, this ... will tell you how much of your target is expressing in each and every cell and can help identify key features that may lead to some other discovery," he said.
Koong noted that customers can also use EMD Millipore's Amnis high-speed cell imaging instrument in their experiments. He said that Amnis "combines best of both worlds" by taking a picture of every cell and correlating morphology with RNA content.
EMD Millipore is currently developing an application using SmartFlare probes to detect intracellular RNA, as well as surface antibodies to look at protein expressed from the same RNA.
"You can do an overlay, and can correlate the RNA content to the protein amount," said Koong.
The company is also looking to expand the multiplexing capabilities of the probes. Currently, customers can use SmartProbes to profile the expression of two targets in the same assay using Cy3 and Cy4 dyes. Koong said that EMD Millipore is developing multicolor metafluorophores that will allow users to look at up to five different targets within a cell.
He said that multiplexing is only limited by "how many fluorescence [signals] you can detect at once."
Koong said that other "exciting" applications are in development. For instance, SmartFlare users can use the probes in in vitro cell culture for a variety of cell lines, but the company is working with collaborators to look at tissues in vivo. "Once you start going down that path the door is wide open in terms of possibilities," said Koong. "We think we have only touched surface of what SmartFlare can do."