Monday, August 8th, 2011
An outstanding example of how plastics benefit humankind is currently making news: A simple, inexpensive credit card-sized diagnostic device called the mChip recently recently proved during field-testing in a remote area of Rwanda that it can detect both HIV and syphilis within 20 minutes, on site, no doctor required. Becoming known as the “lab on a chip,” the card contains the microfluidic channels in which a small blood sample is exposed to reagents. The card is injection molded of transparent plastic. The other two components of the system are also plastic.
Injection molding the mChip in plastic is a major reason it is economical—$2 to $3 for each card according to its lead developer—and why it can be produced in the volume needed to combat the HIV and syphilis epidemics raging in parts of Africa. The testing requires just two microliters of blood, obtainable by pricking a finger.
Dr. Samuel K Sia, leader of the development program, is an assistant professor of biomedical engineering in the Engineering Department of Columbia University (New York, NY). He and his team have published the results of four years of testing in Rwanda in Nature Medicine, online on July 31 and in print on August 4. The results are astounding.
That the mChip detects HIV and syphilis in 20 minutes, and often faster, takes on greater significance when you realize the current alternative is a process that usually takes weeks. A patient living in a remote area must travel to a hospital to give a blood sample, which then is sent to a distant location for laboratory analysis. The lab results then are returned to the hospital. The sequence generally takes one to three weeks, depending on distance and available transportation, which often is limited to walking. An added benefit is that the results do not need laboratory interpretation; they are immediately clear to the person administering the test, and treatment can begin immediately.
A version of the mChip that tests for prostate cancer was developed previously by Claros Diagnostics, a venture capital-backed company started by Sia in 2004, was approved in 2010 for use in Europe. Development of the mChip has been supported by funding from the National Institutes of Health and the Wallace Coulter Foundation.