This technique transforms ordinary paper into a biofunctional medium that could support a variety of diagnostic tests and lower the cost of clinical laboratory testing
Is the clinical laboratory profession ready for a diagnostic technology that uses ordinary copy paper as the foundation for applying the reagents needed to run any number of fast, portable, accurate, and cheap medical laboratory assays? A recent technology breakthrough may make this possible in just a few years.
A bioengineering team at the University of Washington (UWA) has developed a method to stick medically interesting molecules to ordinary copy machine paper. This “chemical trick” opens the door to developing all sorts of paper-based diagnostic tests that are not just cheap, but virtually free, noted a report published by Fierce Medical Devices.
UWA Concept of Paper-based Laboratory Technology is Simple
“We wanted to go for the simplest, cheapest starting material, and give it more capability,” stated Daniel M. Ratner Ph.D., a UW Assistant Professor of Bioengineering and lead author of a paper published in the American Chemical Society journal Langmuir. “We also wanted to make the system as independent of the end applications as possible, something any researcher could plug into.”
Pathologists and clinical lab managers know that there are already many paper-based diagnostics, such as pregnancy tests that are made from a sticky membrane called nitrocellulose. Nitrocellulose is also used by medical researchers to detect proteins, DNA, or antibodies in the human immune system.
Ratner’s idea was to replace this special, sticky membrane with cheap, readily available paper. The hope is that this paper-test medium could be applied to any type of medical test, not just those with big, biological molecules, noted the Fierce Medical Devices report.
How to Transform Common Paper Products Into a Laboratory Test Medium
Ratner’s technique for making biofunctional paper requires minimal equipment and skill. His researchers take divinyl sulfone, a cheap industrial solvent that has been used for decades as an adhesive and can be bought by the gallon, and diluted it with water, carefully controlling acidity. The solution is poured into a Ziploc bag with a stack of paper, shaken for a couple of hours, then rinsed with water and dried. The dried paper is smooth, but sticky to all types of chemicals of medical interest. These include proteins, antibodies, and DNA, as well as sugars and small-molecule drugs used to treat most medical conditions.
“We want to develop something to not just ask a single question, but ask many personal health questions,” explained Ratner. “Is there protein in the urine? Is this person diabetic? Do they have malaria or influenza?”
Testing their idea, the researchers replaced the ink cartridge in an inkjet printer with biomolecules of galactose, a small-molecule sugar that attaches to human cells. They then printed the biomolecules on the treated paper. Next, the treated paper was exposed to fluorescent ricin, a poison that sticks to galactose. The flourescence revealed that the ricin was present, proving the concept is viable.
Ratner hopes that biomedical companies will now use this research to develop actual diagnostic tests.
Potential for Eventual Use in Medical Laboratory Testing
Ratnor and his research team at the University of Washington hope their new concept for medical diagnostics will be used to develop low-cost tests that can be used at the point-of-care in developing countries. However, it is equally true that in vitro diagnostic (IVD) manufacturers could pick up this technology, refine it further, and use it for patient-self test kits sold in retail outlets in developed nations. If this technology lowers the cost of manufacturing such medical laboratory test kits, then IVD manufacturers would certainly be motivated to utilize this technology in their products.