Dipstick and lateral-flow formats have dominated rapid diagnostics over the last three decades. These formats gained popularity in the consumer markets due to their compactness, portability and facile interpretation without external instrumentation. However, lack of quantitation in measurements has challenged the demand of existing assay formats in consumer markets. Recently, paper-based microfluidics has emerged as a multiplexable point-of-care platform which might transcend the capabilities of existing assays in resource-limited settings. Paper-based microfluidics can enable fluid handling and quantitative analysis for potential applications in healthcare, veterinary medicine, environmental monitoring and food safety. Currently, in its early development stages, paper-based microfluidics is considered a low-cost, lightweight, and disposable technology. Our research focuses on (i) fabrication of paper-based microfluidic devices, (ii) functionalization of microfluidic components to increase the capabilities and the performance, (iii) introduction of existing detection techniques to the paper platform and (iv) exploration of extracting quantitative readouts via handheld devices and camera phones. Additionally, we study challenges to scaling up, commercialization and regulatory issues.
1. Yetisen, A.K., Akram, M.S., Lowe, C.R. Paper-based microfluidic point-of-care diagnostic devices. Lab Chip, 13 (12), 2210-2251 (2013) link
* Most read article since 2013, selected for Lab on a Chip Top 10%
* Taught as course material in diagnostic design class in Innovations in International Health at MIT
2. Akram, M.S., Daly, R., Vasconcellos, F.C., Yetisen, A.K., Hutchings, I., Hall, E.A.H. Applications of Paper-Based Diagnostics. Ch. 7. Lab-on-a-Chip and Micro Total Analysis Systems – A Practical Guide, Ed. Castillo, J., Svendsen, W. Springer. 161-195 (2015) link
After a pollen grain lands on the stigmatic surface of the pistil (female structure of the flower), it forms a pollen tube — a long polar process that transports all of the cellular contents, including the sperm. Pollen tubes invade the pistil and migrate past several different cell types, growing between the walls of the stigma cells, travelling through the extracellular matrix of the transmitting tissue, and finally arriving at the ovary, where they migrate up the funiculus (a stalk that supports the ovule), and enter the micropyle to deliver the two sperm cells–one fertilizes an egg and other the central cell. Typically, only one pollen tube enters the ovule through an opening called the micropyle, terminates its journey within a synergid cell, and bursts to release sperm cells. A pollen tube's journey to an egg cell within the pistil therefore involves a series of cell-cell interactions such as attraction, repulsion and adhesion.
We use microfluidic assays to isolate and characterize the signals that control signaling events by employing a variety of traditional approaches (genetics, cell biology, biochemistry) in combination with global approaches (proteomics, microarray and metabolomics).
Yetisen, A.K., Jiang, L., Cooper, J.R., Qin, Y., Palanivelu, R., and Zohar, Y. A microsystem-based assay for studying pollen tube guidance in plant reproduction. J. Micromech. Microeng. 21, 054018 (2011) link