Towards a 100-Fold more sensitive TB diagnostic based on the coffee ring phenomena
Current detection methods for tuberculosis (TB) in low income countries rely on microscopic inspection of a sputum smear to determine whether a patient is infected. This current method requires scanning an entire slide and can take several hours, but only has a detection sensitivity of twenty to sixty percent. A method which takes less time and provides a higher sensitivity is needed. One strategy to increase sensitivity and decrease inspection time would be to concentrate the TB bacilli into a smaller region of the slide. This method would decrease area needed to be examined, and increase the number of bacilli per square millimeter. Our hypothesis is that the coffee ring phenomena can be used to concentrate bacilli to form a small ring like structure, which concentrates the bacilli into a very narrow annular region. We are going to experimentally test, whether we can extract magnetic beads, as a proxy for TB bacilli, from a highly vicious solution, mimicking sputum, and deposit them into a narrow annulus on a glass slide. We have the equipment and study designs in place. Collection of data with a viscous solid has not been performed yet. By comparing the concentration per square millimeter of the coffee ring sample and contrasting it with the sputum sample, we can determine whether the coffee ring phenomena provides a greater sensitivity with less inspection time.