Integrated Nucleic Acid Testing for TB Diagnosis in Peripheral Settings
Arnold and Mabel Beckman Professor
Keck Graduate Institute
April 28, 2016
Foege N130A, Wallace H. Coulter Seminar Room
New methods that enable rapid and affordable diagnosis of tuberculosis (TB) accessible to affected populations in high TB burden countries are urgently needed, to facilitate treatment and limit transmission. We have developed an easy-to-use integrated nucleic acid testing device for TB diagnosis from sputum, consisting of a disposable cartridge and compact, inexpensive, battery operated instrument. This system automates pathogen lysis, nucleic acid extraction, isothermal DNA amplification and lateral flow detection. During process execution, a sputum sample is liquefied and disinfected to mitigating biohazard concerns. This sample is injected into the cartridge, and all other steps are automated, with result provided in <1.5h. Cell disruption and DNA extraction is performed inside a six port active valve containing a miniature bead blender (SimplePrepTM, Claremont BioSolutions). The DNA-containing eluate is combined with dry mastermix reagents in a reaction chamber, which is designed to ensure effective thermal control during subsequent isothermally amplified, and to enable pumping of amplified mastermix into a lateral flow strip chamber for detection. Miniaturized electrolytic pumps and custom valves facilitate liquid handling in the cartridge. The single use closed system cartridge prevents amplicon carryover and contains all needed reagents in thermostable form. Not additional laboratory equipment is required and the system is designed for use by minimally trained personnel in near-patient low-resource settings, to enable TB diagnosis and treatment initiation in the same clinical encounter. We are adapting the system to also diagnose other infectious diseases of global health importance, such as acute Dengue infections.
Angelika Niemz received her undergraduate degree in chemistry in 1992 at the University of Konstanz (Germany), and her PhD in biophysical chemistry in 1999 at the University of Massachusetts (Amherst). After a postdoc in chemical engineering at the California Institute of Technology, she joined Keck Graduate Institute in 2002, where she is now the Arnold and Mable Beckman Professor. In 2009, she worked during a 6-month sabbatical for Roche Molecular Diagnostics. From 2009-2014, she served as Director of Research at Keck Graduate Institute. Her current research focuses on developing assays and devices for near patient infectious disease diagnosis via nucleic acid testing, and on Raman sensors to detect volatile organic compound biomarkers. She teaches courses on medical diagnostics, high throughput technologies, and instrumentation development.