Project Lead(s): Xiaowu (Shirley) Tang
Issue
The World Health Organization states that diarrhea is the second leading cause of deaths in children under the age of five, with the majority of cases occurring in developing countries.
The United Nations declared that one of the four Millennium Development Goals is to reduce childhood mortality, and making inroads into the toll taken by diarrhea would help move towards this goal.
Solution
The project aimed to develop a handy device that is low-cost and portable, and yet sensitive enough for the detection of diarrhea-causing pathogens in water.
Single-walled carbon nanotube thin film (SWNT-TF) sensors have been integrated onto two prototype platforms, test strip-based and microchip-based.
Test strips were devised by taking Accu-Chek glucometer strips, removing the top layer along with chemicals at the tip of each strip, and using the plastic substrate and metal contacts only.
Both prototype platforms can be coupled to an electronic read-out unit to perform pathogen detection.
For pathogen detection, with the strip-based prototype, the strip is inserted into a contact socket, which is connected to an electronic readout device through a ribbon cable, and then the tip of the strip carrying a SWNT-TF sensor is dipped into the test solution.
Outcome
Proof-of-concept testing was done on both a virus model (bacteriophage M13) and a bacteria (E. coli) strain; detection of about 50 virions and a single bacteria in two hours was confirmed.
This indicates that better sample delivery methods to promote virus/bacteria transport to the sensor surface could lead to successful detection at even lower solution concentrations than that showed in the proof-of-concept study.
The approach does not use expensive equipment, and per-test costs can be reduced to just a few dollars.
Great progress has been made in building an industrial partnership to further develop the innovation into feasible products for distribution.