Diagnostics For All (DFA) uses its simple and elegant patterned paper technology to create diagnostic devices to meet the needs of those living in resource-poor regions. Patterned paper is a game-changing technology for delivering low-cost diagnostic devices to support human and animal health in the developing world. Paper is inexpensive, universally available, and compatible with many biological and chemical assays.
The technology that underlies our devices was developed by Professor George Whitesides and his team at Harvard University. DFA holds an exclusive worldwide license from Harvard for medical and other applications of the technology.
To fabricate a diagnostic device, DFA patterns channels and assay zones (or wells) of water-repellant materials into a piece of paper roughly the size of a postage stamp. Biological and chemical assay reagents are then deposited in the wells. When blood, urine, saliva, sweat or other biological samples are applied to the device, the paper wicks the sample through the channels to the assay zones, without external pumps or power. Upon contact, the assay zone quickly changes color and results are then easily read by comparing the color change with a reference scale printed on the device. After use, the device can be easily disposed of by burning. As we develop more advanced diagnostics, DFA’s patterned paper-based devices can be embedded with electrical circuitry to enable resistive heating, electrochemical assays, or initial processing of assay results. Additionally, multiple sheets of patterned paper can be stacked to generate three-dimensional devices capable of automatically performing a variety of complex fluid operations such as splitting, filtration, mixing, and separations.
Inexpensive - Paper is significantly less expensive than other materials typically used in diagnostic devices and is compatible with a variety of existing diagnostic tests. It wicks biological samples to assay zones via patterned channels in the paper without the use of external pumps, and its mesh-like properties filter the sample of contaminants such as dust and dirt. Additionally, paper zones have a high surface area which is useful for deposition of capture and detection agents, such as antibodies.
Lightweight, durable, and self-contained - DFA’s patterned paper-based devices can be brought directly to those who are unable to travel to hospitals or clinics and, with no mechanical parts, are robust enough for use even under severe environmental conditions. No auxiliary equipment, electricity, or laboratory facility is needed to use the device or process a sample. Results are quickly displayed, enabling immediate clinical decisions.
Easy-to-use and easy-to-read - Minimal training is required to use one of these diagnostic tests. They are both user-friendly and minimally invasive. A sample from a finger prick is sufficient to yield results. No syringes are involved and neither clean water nor sample preparation is needed. Results are displayed in an easily understood manner, as through a colorimetric scale.
Reliable and safe - Before distribution, devices are packaged so that they are protected from the environment and provide adequate shelf life for transport and storage in the developing world. While DFA’s patterned paper-based devices are single-use, they can be easily and safely disposed of through incineration, assuring that they do not contribute to the global medical waste problem.
Versatile - The patterned paper technology can be applied to create immunoassasys, electrochemical assays, clinical chemistry assays, and molecular diagnostics.
Ease of manufacturing - Patterned paper-based devices can be manufactured to scale using existing high-volume, low-capital techniques and equipment.
Patterned Paper as a Platform for Inexpensive, Low‐Volume, Portable Bioassays. Martinez AW, Phillips ST, Butte MJ, Whitesides GM. . Angewandte Chemie International Edition. 2007;46(8):1318‐1320.
Simple Telemedicine for Developing Regions: Camera Phones and Paper‐Based Microfluidic Devices for Real‐Time, Off‐Site Diagnosis. Analytical Chemistry. Martinez AW, Phillips ST, Carrilho E, et al. 2008;80(10):3699‐3707.
Three‐dimensional microfluidic devices fabricated in layered paper and tape. Martinez AW, Phillips ST, Whitesides GM. Proceedings of the National Academy of Sciences. 2008;105(50):19606 ‐19611.
Understanding Wax Printing: A Simple Micropatterning Process for Paper‐Based Microfluidics. Carrilho E, Martinez AW, Whitesides GM. Analytical Chemistry. 2009;81(16):7091‐7095.
Paper‐Based ELISA. Cheng C,
Martinez AW, Gong J, et al. Angewandte Chemie International
Measuring Markers of Liver Function Using a Micro‐Patterned Paper Device Designed for Blood from a Fingerstick. Vella SJ, Beattie PD, Cademartiri R, et al. Anal. Chem. 2012.