New device to detect disease with drop of blood

Scientists, including one of Indian-origin, have developed a gen-next device that may enable detection of disease or virus from just one drop of liquid, including blood.

New Jersey Institute of Technology (NJIT) research professors Reginald Farrow and Alokik Kanwal with colleagues 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.

"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," said 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," Farrow said.

In the study, the NJIT researchers 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 added.

"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," he said.

The device utilises standard complementary metal oxide semiconductor (CMOS) technologies for fabrication, allowing it to be easily scalable (down to a few nanometers). Nanotubes are 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. Nanotubes were found to be crucial to successfully detect the presence of cells.

Carbon nanotubes are very strong, electrically conductive structures a single nanometer in diameter. That's one-billionth of a metre, or approximately ten hydrogen atoms in a row.

Farrow's 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.