As a field which seems to be generating a stream of continual innovation and promise, microfluidic technologies for point of care testing are no stranger to the pages of Medgadget. A recent innovation in this field is the development of low-cost, paper-based, printable microfluidic platforms. A recent study in the journal Biosensors and Bioelectronics by researchers at the University of Shandong and the University of Jinan in China describes a new paper-based electrochemical immunoassay device for point of care testing.
The sensor is comprised of one layer of wax-patterned paper, and one layer of screen-printed electrodes on a transparent polymer substrate. The device works like may of the existing microfluidic cartridges with samples deposited in the patterned wells where electrical readings are performed via the electrodes to determine analyte concentrations in the sample. The new sensor demonstrated a high level of linearity over a range of sample concentrations.
According to the research team there are a number of advantages to paper-based microfluidic technologies:
Microfluidic paper-based analytical devices are (1) exceedingly inexpensive, (2) easily fabricated for rapid prototyping of new designs, (3) made from abundant raw materials, (4) conveniently incinerated for rapid disposal of hazardous waste and (5) stand-alone devices that do not require external pumps or other complicated equipment to move fluids.
It is important to note that paper based immunoassay systems have been developed over the last 5 years or so using colorimetric immunoassay approaches, however the Chinese researchers believe that theirs is the first paper based system to implement an electrochemical immunoassay. Who knows, maybe the days of DIY point of care devices are just around the corner.
Abstract in Biosensors and Bioelectronics: Paper-based three-dimensional electrochemical immunodevice based on multi-walled carbon nanotubes functionalized paper for sensitive point-of-care testing