Tubercle bacillus, aka. Tuberculosis or TB, is a very common, very infectious, and if untreated, very lethal disease. A well dated illness, its origins can be traced back to early Neolithic Revolution, and is often attributed to animal husbandry (specifically, the domestication of bovines). And in terms of the number of people carrying it, and the number of deaths associated with it, it is second only to HIV.
Because of this and the fact that the disease remains incurable – the only way to combat it is with early detection or experimental vaccines – it is obvious why medical researchers are looking for better ways to detect it. Currently, the standard test for tuberculosis involves inserting a hypodermic needle into a person’s arm at a very precise angle and depth, using a small trace of genetically modified TB to elicit an immuno-reaction.
As anyone who has undergone this test knows (as a teacher, I have had to endure it twice!), it is not a very efficient or cost effective way of detecting the deadly virus. In addition to being uncomfortable, the telltale symptoms can days to manifest themselves. Hence why Researchers at the University of Washington hope to replace this test with a painless, near-automated alternative – a microneedle patch that they say is more precise and even biodegradable.
For their study, which was recently presented in the journal Advanced Healthcare Materials, the scientists used microneedles made from chitin – the material that makes up the shells sea creatures and insects and is biodegradable. Each needle is 750 micrometers long (1/40th of an inch) and is coated with the purified protein derivative used to test for tuberculosis.
In terms of its application, all people need do is put it on like a bandage, which ought to make testing on children much easier. For the sake of testing it, the team tested its microneedle patch on guinea pigs and found that the reaction that occurs via the hypodermic needle test also appeared using the patch. But the best aspect of it is the fact that the patch does not require any invasive or difficult procedures.
In a school news release, Marco Rolandi – assistant professor of materials science and engineering at the University of Washington and lead author of the study – had the following to say:
With a microneedle test there’s little room for user error, because the depth of delivery is determined by the microneedle length rather than the needle-insertion angle. This test is painless and easier to administer than the traditional skin test with a hypodermic needle.
The researchers report that they now plan to test the needle patch on humans and hope to make the patch available in the near future. However, the long-term benefits may go beyond stopping TB, as Rolandi and his team hope that similar patches will be developed for other diagnostic tests, such as those used to detect allergies. As anyone who has undergone an allergen test will tell you (again, twice!), its no picnic being pricked and scraped by needles!
As always, the future of medicine appears to be characterized by early detection, lower costs, and less invasive measures.