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Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Poster Abstracts
53
13-POS
Board 13
Spot Immuno-Magnetic Capture for Isolation and Detection of Salmonella Typhi
Ravikrishnan Elangovan
1
, Saurabh Singh
3
, Mohita Upadhyaya
3
, Vikas Pandey
2
, Shalini
Gupta
2
, Vivekanandan Perumal
3
.
1
Department of Biochemical Engg and Biotechnology, Indian Institute of Technology, New
Delhi, India,
2
Department of Chemical Engineering, Indian Institute of Technology, New Delhi,
Delhi, India,
3
Kusuma School of Biological Science, Indian Institute of Technology, New Delhi,
India.
Circulating tumor cells, fetal cells or pathogen cells in peripheral blood can be present at
concentration less than 10 cells/ml, and are classified as rare cells. Sensitive detection of
circulating tumor cells or pathogen cells could empower physician to execute effective treatment.
Clinically relevant concentration for detecting circulating tumor cells or S. typhi cells in blood
can be as low as 0.2-2 cells/ml. At this low concentration, even the presence of a single cell
becomes a Poisson distribution, to diagnose with high confidence one need to analyze a larger
sample volume, typically 5-10 ml of patient blood is used for a single test. Current methods for
rare cell detection include micro/nano patterned single use chips manufactured in clean room
facility and involve automated scanning for detection. These methods are expensive and not
affordable in developing countries. We have developed a low cost, milli-fluidic chip and
immuno-magnetic enrichment method that allows enrichment of rare cells by 100,00X/ml. We
have demonstrated the principle by capturing fluorescently labeled S. typhi cells using 100 nm
magnetic particles with anti-typhi antibodies. Sample was processed at 200µl/min with 90%
capture efficiency to a 1.6 mm capture spot with final volume of 100 nl. 100000X target
enrichment allows us to improve the limit of detection of fluorescence imaging from 100000
CFU/ml to 1 CFU/ml.