Lab on a Chip

Cancer is the second major cause of death worldwide and can be ascribed to the difficulty to detect the early onset of the disease in order to begin treatment before the cancer spreads. The problem is there are very few macroscopic indicators of cancer. Axel Scherer from the California Institute of Technology, who recently partnered with Dartmouth’s Thayer School of Engineering, presented a variety of projects in the nanotechnology arena at the weekly Jones Seminar last Friday. 

Scherer has developed the concept for a lab on a computer chip with the ability to detect very low levels of cancer protein markers that could help doctors detect cancer through a quick non-invasive blood test. But that is just one part of his research. He is looking at tests for blood glucose levels for diabetes patients, handheld polymerase chain reaction automates with the ability to check for genetic diseases, and faster more powerful semiconductors and transistors. 

How does he accomplish all of this?  Nanoscale lithography. Lithography is an ancient process that dates back to Gutenberg and the printing press. Lithography is the process of using lasers, x-rays, atomic force microscopy, and other devices to “print” nanoscale circuitry and nanoscale structures on silicon surfaces. Figure 1 shows the basic structure and size of one of these microfluidic chips that the lab produces.  The lab uses microscopes to visualize cells as the lab on a chip processes them. 

The primary scope of his lab is the advancement of nanolithography in the medical field. With a grant from the Bill and Malinda Gates Foundation, the lab is focused on bringing their lab on a chip to the field in third world countries. The lab has developed $200 battery powered polymerase chain reaction (PCR) machine that is 100% mobile and the size of a penny. PCR is used to amplify DNA for analysis, and machinery is usually expensive.  His machine will allow for genetic screening for a variety of disorders in third world countries that lack proper medical technologies. 

In addition, the lab has developed a cancer blood testing device (Figure 2) that uses nanochannels etched on the surface of a silicon chip that are saturated with antibodies that can recognize cancer markers and fluoresce if these markers in the blood bind to the antibodies.  The technology promotes high specificity and can react to very low levels of protein, which makes it an optimal pharmaceutically relevant system to screen for cancer. 

The final focus of the lab is in the electrical world.  How they can implement nanostructures to maximize their properties for a variety of computational and electrical capacities.  One structure the lab likes to meddle with is silicon pillars (Figure 3).  These pillars you might say act like normal silicon, but for some reason on the nanoscale these pillars have conductive and photoelectric properties.  They even have the ability to bend with flexibility inexistent to normal macroscopic silicon structures. 

Taken together, the lab has shown that nanolithography and microfluidics can play a huge role in changing the way we diagnose diseases and monitor body levels.  A chip the size of a penny could be developed, implanted in the body and easily read out cancer diagnosis, glucose levels, blood pressure, and other aspects of our body chemistry.  Nanotechnology also offers a cheaper and more efficient mode of developing both new medical devices and electronics.  Scherer calls his work “translational” because he has taken the concept of a “chip in a lab to a lab on a chip”.

Figure 1: Lab on a chip with the ability to collect cells break them up and analyze their DNA to check for diseases

Figure 2: Image of the cancer blood test with the ability to detect very low levels of proteins that are indicative of cancer. The technology implements the ability of antibodies to bind and fluoresce to these protein markers to be able to detect and report these levels to the physician.

Figure 3: A microscopic image of silicon pillars generated on the surface of a wafer crystal monolayer. These nanostructures have computational and conductive properties that can only be witnessed on the nanoscale