Bhushan J. Toley's Talk

Mar 09, 2016 - 15:00

Mar 09, 2016 - 16:00

Room 118 Department of Chemical Engineering

Seminars

Bhushan J. Toley University of Washington USA

Abstract: The first step in the treatment of any pathological condition is its diagnosis. Currently most medical diagnostic tests are conducted in centralized labs using bulky and expensive instruments that require trained users to operate. This infrastructure-heavy model of acquiring medical diagnostic information restricts access to proper medical diagnosis for many especially in the developing world. In this talk I will present a new vision of medical diagnostic testing in which state-of-the-art diagnostic tests are miniaturized into handheld devices that can be operated by untrained users. I will present proof-of-concept that this can be accomplished by using “paper-based microfluidics” (PµF). In PµF devices fluids flow under capillary pressure generated by porous materials which eliminates the need for bulky pumps to drive fluids. Our goal was to develop a fully automatic and disposable nucleic acid amplification test (NAAT) device that can be operated by an untrained user. In a NAAT the patient sample goes through sequential physical and chemical treatment steps and the net outcome is generation of billions of copies of the target DNA or RNA. In this sense it is much like a ‘chemical process’ comprising of multiple unit operations conducted in different zones of a PµF device which are connected by ‘valves’. Valving in the absence of electricity or batteries in PµF devices was initially a challenge. I will present several new power-free valving strategies for PµF devices that enable conducting automatic multi-step fluidic operations. I will then briefly describe the molecular biology of isothermal strand displacement amplification (iSDA) a method of amplifying DNA and RNA targets. I will present a simple kinetic model of iSDA that demonstrates the competition between specific and non-specific amplification reactions and helps improve theoretical understanding of the molecular mechanism. Finally I will present one approach to designing a fully automated sample-to-answer NAAT device that fits in the palm of your hand. This technology has the potential to reduce the cost of and increase access to molecular diagnostic testing globally.About the speaker: Dr. Bhushan J. Toley is a postdoctoral researcher (Senior Fellow) in the Bioengineering Department at the University of Washington where he works in the lab of Dr. Paul Yager. Dr. Toley received a bachelors degree in Chemical Engineering from the Institute of Chemical Technology Mumbai in 2006 and a PhD in Chemical Engineering from the University of Massachusetts Amherst in 2012. His current research interests are in increasing access to and reducing the cost of state-of-the art healthcare diagnostic technologies. To this end Dr. Toley has been interested in the use of paper-based microfluidics for pump-less fluid flow in low-cost devices. During his PhD research Dr. Toley studied the transport of drugs in 3D tumor tissues and developed in vitro models of perfused tumor tissues that can be used for better assessment of cancer therapeutic drugs.