Using a standard inkjet printer, researchers at the Stanford University School of Medicine Genome center claim to have created a reusable diagnostic "lab on a chip" that costs just 1 cent to make. This new technology could help vastly improve diagnostic capabilities worldwide, and help accelerate research by providing access to analyze cells and diagnose diseases cheaply and easily.
According to the researchers, cheap diagnostic tools such as this could markedly improve medical outcomes in much of the developing world. With breast cancer survival rates at only about 40 percent in poor countries, and other deadly diseases, such as tuberculosis, malaria, and HIV being rife, early intervention through the use of such an accessible diagnostic tool may well save many lives.
"Enabling early detection of diseases is one of the greatest opportunities we have for developing effective treatments," said Rahim Esfandyarpour, PhD, an engineering researcher at Stanford's Genome Center. "Maybe $1 in the US doesn't count that much, but somewhere in the developing world, it's a lot of money."
A two-part system, the lab-on-a-chip uses an amalgam of microfluidics (the technology of manipulating and controlling fluids at miniature scales), electronics, and inkjet printing to create the connecting circuitry. A transparent microfluidic chamber made from silicone makes up the first part of the chip, and provides a receptacle for the cells being tested, and a cover for the component area of the reusable electronic strip. The second part is a polyester film with circuits created using a readily-available conductive nanoparticle ink, that's applied using a regular inkjet printer.
"We designed it to eliminate the need for clean-room facilities and trained personnel to fabricate such a device," said Esfandyarpour. "One chip can be produced in about 20 minutes."
Intended for use as a multifunction unit, one application includes the ability to analyze various cell types without the need for fluorescent or magnetic markers usually needed when tracking cells. Rather, the unit isolates cell types using their innate electrical properties in a process known as dielectrophoresis. That is, when electric current flows through the the inkjet-printed strip, the cells that have been distilled into the microfluidic chamber are moved in various directions depending on their "polarizability."
In other words, as the electrons in the atomic make-up of different cells respond with varying degrees of charge distribution to an applied electric current by forming unique magnetic fields, so too the cell containing them will tend to move in a specific direction influenced by those magnetic fields. This method of analysis, say the researchers, vastly improves precision and reduces intricate and time-consuming labeling methods.
Apparently able to perform the processes associated with much more complicated and expensive diagnostic equipment, such as segregating single cells from a mixture, isolating rare or uncommon cells, and enumerating cells based on type, the cost of Stanford's lab-on-a-chip is many times cheaper than the individual devices normally required to carry out each of those functions. The researchers cite the example that a standalone flow cytometer machine used by laboratories to sort and count cells costs somewhere in the region of US$100,000 to buy, and even more when on-going costs are included.
"The motivation was really how to export technology and how to decrease the cost of things," said Ron Davis, PhD, professor of biochemistry and of genetics and director of the Stanford Genome Technology Center. "The genome project has changed the way an awful lot of medicine is done, and we want to continue that with all sorts of other technology that are just really inexpensive and accessible."
The researchers believe that the inexpensive nature of their device may also open up a whole new world of inexpensive, easily-accessible medical diagnostics in a way that low-cost DNA sequencing now allows doctors to investigate the DNA of tumors readily and easily. Similarly, the lab-on-a-chip may also provide the means to detect tumor cells in the bloodstream and allow earlier cancer diagnose.
Much less complicated than full-blown photonics-based devices, but still more capable than simple paper-based multiple test-strip tools, the researchers are hopeful that their device will spark a revolution in diagnostic tools for medical research by making readily-available, inexpensive equipment available to almost everyone.
"I'm pretty sure it will open a window for researchers because it makes life much easier for them — just print it and use it," said Esfandyarpour.
The results of this research were recently published in the journalProceedings of the National Academy of Sciences