A prototype lab-on-a-chip could soon enable a doctor to detect disease or virus from just one drop of liquid, including blood.
New Jersey Institute of Technology research professors Reginald Farrow, a carbon nanotube specialist, and Alokik Kanwal, his former postdoctoral fellow, have created a carbon nanotube-based device to noninvasively and quickly detect mobile single cells with the potential to maintain a high degree of spatial resolution.
The research was originally funded by the military as a means to identify biological warfare agents, but Farrow believes its applications can go much further and potentially detect viruses, bacteria, even cancer. The research may also someday even assess the health of good cells, such as brain neurons.
"Using sensors, we created a device that will allow medical personnel to put a tiny drop of liquid on the active area of the device and measure the cells’ electrical properties,” says Farrow.
“Although we are not the only people by any means doing this kind of work, what we think is unique is how we measure the electrical properties or patterns of cells and how those properties differ between cell types.”
The research, due to be published on July 15 in journal Biosensors and Bioelectronics but available now online, explains how the pair’s team evaluated three different types of cells using three different electrical probes.
“It was an exploratory study and we don’t want to say that we have a signature,” Farrow adds. “What we do say here is that these cells differ based on electrical properties.
“Establishing a signature, however, will take time, although we know that the distribution of electrical charges in a healthy cell changes markedly when it becomes sick.”
Since 2010, three US patents, have been awarded for the device and more have been filed.
The device is built using standard complementary metal oxide semiconductor (CMOS) technologies, allowing it to be easily scalable (down to a few nanometres) with nanotubes deposited using electrophoresis after fabrication in order to maintain CMOS compatibility.
The devices are spaced by six microns which is the same size or smaller than a single cell. To demonstrate its capability to detect cells, the researchers performed impedance spectroscopy on mobile human embryonic kidney (HEK) cells, neurons from mice, and yeast cells.
Measurements were performed with and without cells and with and without nanotubes, but the nanotubes were found to be crucial to successfully detect the presence of cells.
Carbon nanotubes are very strong, electrically conductive structures a single nanometre in diameter and Farrow’s major breakthrough is a controlled method for firmly bonding one of these submicroscopic, crystalline electrical wires to a specific location on a substrate.
His method also introduces the option of simultaneously bonding an array of millions of nanotubes and efficiently manufacturing many devices at the same time.
According to Farrow, being able to position single carbon nanotubes that have specific properties opens the door to further possibilities such as an artificial pancreas, three-dimensional electronic circuits and nanoscale fuel cells with unparalleled energy density.