Researchers from the University of Central Florida, CFD Research, and the University of Illinois have married solid-state electronics and cellular assays to create a non-invasive, high-throughput electrophysiological platform that can determine the effects of drugs on live cells over time.
Armed with almost $1.3 million in funding over the next three years from the National Institute of Biomedical Imaging and Bioengineering, the researchers hope to commercialize the device in that same time frame through a startup company, and eventually want to hone the platform for additional applications such as high-throughput functional genomics.
The unnamed technology consists of live neuronal cells patterned onto a chip embedded with metal microelectrodes. The cells are patterned in such a way to form electrical seals between individual cells and the microelectrodes. This, in turn, allows users to make electrophysiological measurements of changes in the cells’ action potentials.
Most current high-throughput electrophysiology instruments use parallel patch clamping, a relatively invasive procedure in which a glass pipette is essentially inserted into a cell to make measurements, James Hickman, director of the University of Central Florida’s Nanoscience Technology Center and principal investigator on the NIBIB grant, told CBA News this week.
The technology being developed by Hickman and colleagues, meanwhile, will attempt to measure action potentials without disrupting the cells, Hickman said.
“We’re trying to do what is called a maxi-patch, or on-cell patch, where we don’t break the membrane,” Hickman said. “All the other things out there require that you break the membrane. If we don’t break the membrane, we can now start conducting temporal analyses to look at these things over weeks.
“Anybody who’s ever done electrophysiology using patch clamp knows that effectively it is similar to if you took a human being, and put a huge spear in [his] chest and [told him] to act normal,” Hickman added. “It’s just not going to happen. So we think this is a non-invasive way of looking at membrane potential changes.”
While it’s true that many traditional instruments for HT electrophysiology use invasive methods, Molecular Devices, widely considered the market leader for HT electrophysiology instrumentation, sells the IonWorks and PatchXpress product lines, both of which use less-invasive planar patch clamp methods. So too do instruments from Molecular Devices competitors such as Flyion and Sophion.
But another major differentiator between these types of instruments and the technology being developed by Hickman and colleagues is that the former are generally only used to measure ion channel activation for basic research purposes or for screening ion channel-modulating drugs.
Hickman’s team, meanwhile, purports to be able to monitor changes in cellular action potential and turn them into information about more general cellular pathways through mathematical analysis.
“In some of our early research, when we hit cells with a large number of different toxins, we found that the action potential was affected by all of them except for one,” Hickman said. “At the time, everybody was saying that neurons are only going to be affected by neurotoxins.
“But when you think about it, 75 percent of the genome in every one of our cells is conserved, so there are a lot of redundant pathways,” he added. “It may not be the primary pathway, but toxins that affect, say, liver cells are probably going to affect neurons too, because those receptors are still going to be there.”
Hickman said he and his team immediately saw the implications for drug screening, even outside of ion channel-modulating compounds.
“This was very interesting, because we could then say ‘Wow, we’re going in through a receptor, and we’re seeing changes in the action potential, so somehow these receptors must be connected through pathways in the cells back to ion channels,’” Hickman said. “We see a differential change in the ion currents through one channel versus another. We can then relate that directly to an action potential change.”
The researchers will primarily use the money from NIBIB to begin relating measured changes in action potential to the activation of various receptors or cellular pathways. To do this, Hickman’s group at UCF is collaborating with CFD Research, a software development firm based in Huntsville, Ala.
“We’re in the process of setting up the models,” Hickman said. “We’re trying to develop the database of action potential changes and plug it into their analysis codes – of creating the interface between our data and their existing programs.”
Hickman said that Bruce Wheeler, a faculty member at the Neural Engineering Lab at the University of Illinois at Urbana-Champaign, is acting as a consultant to the project, and also offers specific expertise in the way of algorithm development and modeling cellular action potentials.
“Anybody who’s ever done electrophysiology using patch clamp knows that effectively it is similar to if you took a human being, and put a huge spear in [his] chest and [told him] to act normal.”
One specific challenge the researchers will have to address is creating a tight enough seal between the microelectrodes and cells to measure signals with adequate fidelity to provide meaningful data. This can also be a problem with the aforementioned planar patch clamp methods. Hickman said that addressing this issue is a specific goal of the NIBIB grant.
Finally, Hickman and colleagues would eventually like to fine-tune the platform into an instrument for conducting high-throughput functional genomics, or measuring the effect of a gene product on a cell’s function. This would be accomplished by engineering cells to express specific genes, and then by “actually looking at what a gene does in real time, we might be able to glean something about its function,” Hickman said.
But first the researchers will move to commercialize the technology for drug-discovery or toxicology applications, Hickman said. To do so, they have formed a very early-stage startup company called Hesperos.
“When a venture capitalist looked at this several years back, he said that if it was successful, it could capture maybe 40 percent of the drug-discovery market,” Hickman said. “I think that’s a bit high, but hey, even five percent would be great.”
The company will eschew VC cash for now, relying solely on the NIH funding, but Hickman added that he would be open to an angel investor if it were the “right person.” Hickman also said the group hopes to commercialize the electrophysiology chips by the time the NIBIB grant ends in 2009. The researchers received about $430,000 toward the project beginning in September, and expect to receive approximately the same amount the following two years.
Hickman has filed for three separate patents on the technology and associated methods, but no patents have yet been issued.