ITP on a hand held device
Kaigala, G.V., Bercovici, M., Behnam, M., Elliott, D., Santiago, J.G. & Backhouse, C.J.
- Hand-held CE device developed by Govind Kaigala et al. at Christopher Backhouse group (University of Alberta, Canada). Adapted jointly for use with ITP.
- First demonstration of ITP on a portable, hand-held device.
- Demonstrated direct fluorescent detection LoD of 100 pM, and indirect detection LoD (based on the FCA assay) of 10 uM.
Despite such diverse and widespread applications of ITP, on both traditional capillaries and microchips, the use of this technique has been limited to a laboratory setting as the necessary infrastructure is typically bulky, expensive and complex (e.g. power supply, microscope). The wider application of ITP outside a typical laboratory will require highly portable and cost-effective instrumentation. In this work, we demonstrated a portable, low-cost ITP instrument.
Hand-held portable ITP device
The group of Prof. Christopher Backhouse at University of Alberta, Canada, has been progressively shrinking lab on a chip instrumentation while incorporating components which are cost-effective and compatible with capillary electrophoresis (CE) systems with LIF detection. The instrument is (a cell phone sized version of the previous system) presented here was developed by Kaigala et al. at the Backhouse group and adapted jointly for use with ITP. We show it is possible to overcomes some of the earlier limitations of low sensitivity by integrating ITP to increase the signal.
Figure 1. the hand-held ITP instrument (dimensions: 7.6 x 5.7 x 3.8 cm) is powered using a standard USB link connected to a laptop computer. The instrument is self-contained and includes a 5 mW laser, a photodiode, high voltage generation, switching, and communication functionality. The metal casing acts as a Faraday cage to reduce the effects of environment noise.
Figure 2. Focusing and direct detection of a fluorescent species (Alexa Fluor 647) using “peak mode” ITP in our portable device. The response of the detector was linear with the initial concentration of the analyte. Five repetitions were performed at each analyte concentration. The uncertainly bars represent a 95% confidence interval on the mean value, based on the Student t distribution. The inset shows a superposition of actual signal data registered by the hand-held device for four initial concentrations.
Figure 3. Detection of unlabeled 2NP and TCP in tap water using the hand-held ITP device. LE and TE composition as the same as in Figure 5. 200 V was applied along a 23 mm channel with a 17:1 cross section area variation (the detection region is 17 mm long). Despite lower available voltage and longer analysis time, the handheld device successfully detects both toxins.
- Kaigala, G.V., Bercovici, M., Behnam, M., Elliott, D., Santiago, J.G. & Backhouse, C.J. Miniaturized system for isotachophoresis assays. Lab Chip 10, 2242 (2010).