Quick and easy way to check the quality of pharmaceuticals. The user crushes the pill and wipes some of the powder across the test card, then dips the bottom of the card into water to activate twelve color tests. In three minutes, the results of the tests can be read as a colored bar code.
Our guiding design principle is simplicity of use. We design the PAD as a complete lab on a piece of paper--the user does not need to add anything other than the medicine to be tested and water. The test card stores the reagents, mixes them in the correct order, and brings them to the drug sample. The user does not need any instruments or supplies, other than the test card itself, and the cards can be run on the corner of a table in conditions found in tropical Africa.
Fabrication of the test cards: The paper test cards contain a library of chemical color reactions, each isolated in its own reaction lane by hydrophobic barriers that are printed onto the paper. We start with Ahlstrom 319 chromatography paper, which is a heavy paper made of pure cellulose fibers. We use a color laser printer to print the QR code, color standards, and lane labels, then a Xerox ColorQube wax printer is used to print the lines that will separate the lanes. After a quick bake to make the wax soak into the paper, the test cards are cut out. We use a Biomek spotting robot to place spots of different reagents into the lanes, inspect to make sure everything looks correct, and then stamp the test cards with a serial number. We have made over 12,000 test cards.
Chemistry for detection of falsified drugs: The twelve lanes contain all the reagents needed to carry out tests for different chemicals and functional groups. For example, one lane contains copper(II) and a base; these materials give a characteristic forest-green color with any beta-lactam type antibiotic. Another lane contains a series of reagents that generate a reactive species that can detect phenol groups, found in drugs like acetaminophen or amoxicillin. Other lanes specialize in detecting inert fillers like maize meal, or substitute drugs like aspirin that might be slipped into a formulation in place of a more expensive medication. More information about the lane chemistry is available in our 2013 publication in Analytical Chemistry. We're always looking for more chemistry to expand the types of drugs we can detect.
The contents of a pharmaceutical generate a color bar code. Even if each lane only gave a "yes/no" output, the 12 lanes together could produce as many as 4000 unique chemical fingerprints. Many of the lanes give more than one color, or can produce colors in different locations within the lane. That gives a huge number of potential output states for each test card, each one a different color bar code. Since computers are good at reading bar codes, we are developing computer software to read the test outputs automatically.
How well do the tests work? To date, the paper devices can make fingerprints for 44 different pharmaceuticals, 29 of them unique. We are also able to identify substandard pharmaceuticals based on differences in chemical composition.
What Evidence do you have that your Innovation works?
Visual Recognition of Paper Analytical Device Images for Detection of Falsified Pharmaceuticals, S. Bannerjee, J. Sweet, M. Lieberman, P. Flynn, and C. Sweet, WACV 2016: IEEE Winter Conference on Applications of Computer Vision, March 7-9, Lake Placid NY.
"Paper analytical devices for fast field screening of beta lactam antibiotics and anti-tuberculosis pharmaceuticals" A. Weaver, H. Reiser , T. Barstis, M. Benvenuti , D. Ghosh, M. Hunkler , B. Joy, L. Koenig , K. Raddell , M. Lieberman, Analytical Chemistry, 2013, 85 (13), 6453–6460 Full text behind pay wall at http://dx.doi.org/10.1021/ac400989p (or request from email@example.com)
Other publications (conference)
"Lab-on-paper developed to monitor iodized salt," N. Myers, M. Lieberman, ICCIDD newsletter May 2014
"Paper analytical devices for detection of low-quality pharmaceuticals," A. Weaver* and M. Lieberman, Proceedings of the SPIE - The International Society for Optical Engineering, 2014, Vol. 8976 89760H-1
"Catching the counterfeits," E. Bajema, T. Barstis, and M. Lieberman, Chemistry & Industry, 77: 28–30. 2013 doi: 10.1002/cind.7701_6.x
“Bounded Crowd Sourcing: A twist on open crowd sourcing offers promise for global health efforts,” M. Lieberman, E. Michael, and J. Bock, Monday Developments (a monthly magazine of in-depth news and commentary on global trends that affect relief, refugee, and development work as a service to U.S. humanitarian organizations), July 2011, 29(9), 27-28.
What is your strategy for expanding use of your innovation?
We are looking for partners in low and middle income countries interested in exploring this technology. We would be particularly interested in working with medical regulatory agencies or drug regulatory agencies that possess some capacity for confirmatory testing but are swamped by the need to perform screening tests. We can send samples of the cards to groups that are interested in trying them out.
We are working on two main aspects for scaling the PAD project
1) Development of an automated image analysis program, so users can upload photos of the test cards and receive an immediate text with the results of their pharmaceutical.
2) Prototyping a roll-to-roll printing process that can make 50,000 PADs in an 8 hour shift.