Dielectrophoretic dots: development of hardware for realtime cellular assessment

Lead Research Organisation: University of Surrey
Department Name: Civil and Environmental Engineering

Abstract

Dielectrophoresis (DEP), the motion of polarisable particles in non-uniform fields, has already been shown to be effective for the determination of the dielectric properties of cells for electrophysiological investigation. Applications have been demonstrated from drug screening to extending our understanding of cancer biology. However conventional methods for dielectrophoretic analysis are not well suited for large numbers of parallel experiments, due to the complex nature of electrode fabrication, the very low effective volumes (of the order of nanolitres) in which DEP is effective, and the difficulty in making simple observations of many cells (which are typically microscope-based). In this proposal, a new system of DEP analysis will be constructed using parallel arrays of electrodes (the so-called dot electrodes ). Electrode technology recently developed at the University of Surrey has produced a novel electrode structure for DEP, for which a patent has recently been filed. Whereas previous DEP studies have used electric fields generated by planar (effectively 2D) electrodes etched from gold across the surface of a microscope slide, the new technology uses parallel-plane dot electrode structures to generate simple-to-interpret DEP data rapidly (of the order of 10-20 seconds). The system operates as follows. The dielectrophoretic dot chambers are filled with cell suspension, followed by the drug candidate. An array of dots will be energized by perhaps 20 frequencies, one to each dot, so that the whole spectrum can be obtained simultaneously. The dots will be of sufficient size and spread to ensure the whole array is visible simultaneously using the microscope. Upon the application of the electric field, positive dielectrophoresis removes the cells from the bulk liquid and reduces light scattering, whereas negative dielectrophoresis focuses particles in the middle of the dot and increases light scattering. A high-resolution digital camera uses image-processing algorithms to analyse the change in cell distribution, at a specific time after the application of the field, and hence determine the dielectrophoresis spectrum. This novel approach will enable observation of much more rapid cellular phenomena; in this project the equipment will be demonstrated by observation of cancer drug action and in the onset of cell toxicity, and the onset of apoptosis. All three of these represent important aspects of the study of pharmacology and toxicology, for which fields this project has potential to impact significantly.

Publications

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Description EPSRC-MILES Scheme
Amount £9,984 (GBP)
Funding ID EP/I000992/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 03/2013 
End 01/2014
 
Description Collaboration with University of California at Irvine 
Organisation University of California, Irvine
Country United States 
Sector Academic/University 
PI Contribution We brought expertise and equipment for the development of dielectrophoresis for the analysis of neural stem cells
Collaborator Contribution The US group brought skills and knowledge relating to neural stem cells, as well as providing the cells themselves
Impact This work was highly multi-disciplinary, involving engineers and cell biologists to explore the applicaiton of electric fields for the analysis and sorting of neural stem cells. As a result of this work we have produced a well-cited paper. Our colleagues in the US have used this work to secure research funding from a California funding organisation (CIRM), which they have used to further this collaboration through the purchase of equipment.
Start Year 2009
 
Description MILES: Looking for electrical signatures in red blood cells 
Organisation University College London
Department MRC Laboratory for Molecular Cell Biology
Country United Kingdom 
Sector Academic/University 
PI Contribution We found that there are significant electrophysiological changes in red blood cells at different times of the day. The results demonstrated that circadian electrophysiological activity does take place in red blood cells.
Collaborator Contribution The partners have provided valuable contributions into the potential underlying cellular mechanisms that are responsible for the changes in electrophysiological activity. The collaboration has resulted in a BBSRC bid that we have submitted in September 2014
Impact The team comprises a team of scientists from the areas of biophysics (Surrey), cell biology (Surrey, MRC LMB and cambridge), molecular biology (Surrey, MRC LMB and Camridge) and neurosciences (Cambridge). This multi-disciplinary collaboration resulted in a BBSRC bid that was submitted in September 2014, with a BBSRC reference number is BB/M021556/1. The results of this work is currently being prepared for submission to the journal: Cell.
Start Year 2014
 
Description MILES: Looking for electrical signatures in red blood cells 
Organisation University of Cambridge
Country United Kingdom 
Sector Academic/University 
PI Contribution We found that there are significant electrophysiological changes in red blood cells at different times of the day. The results demonstrated that circadian electrophysiological activity does take place in red blood cells.
Collaborator Contribution The partners have provided valuable contributions into the potential underlying cellular mechanisms that are responsible for the changes in electrophysiological activity. The collaboration has resulted in a BBSRC bid that we have submitted in September 2014
Impact The team comprises a team of scientists from the areas of biophysics (Surrey), cell biology (Surrey, MRC LMB and cambridge), molecular biology (Surrey, MRC LMB and Camridge) and neurosciences (Cambridge). This multi-disciplinary collaboration resulted in a BBSRC bid that was submitted in September 2014, with a BBSRC reference number is BB/M021556/1. The results of this work is currently being prepared for submission to the journal: Cell.
Start Year 2014
 
Title Assembly of cellular arrays for high throughput screeening applications 
Description  
IP Reference  
Protection Patent granted
Year Protection Granted
Licensed No
 
Title 3DEP CLINICAL 
Description The 3DEP system uses electric fields to analyse cell samples using multi-frequency analysis. Working with collesgues in the NHS, we have found that brush samples collected from patients presenting with oral cancer can be discriminated from those with benign lesions or normal samples. Where the sample is not contaminated with blood, system efficacy reaches as high as 100% sensitivity and 94% specificity. We are now working on improved sample preparation to eliminate blood contamination ahead of a wider clinical trial. 
Type Diagnostic Tool - Non-Imaging
Current Stage Of Development Early clinical assessment
Year Development Stage Completed 2014
Development Status Under active development/distribution
Impact Once the sample preparation stage is improved, this technology will save up to 1000 lives in the UK per year, and £30M in treatment costs to the NHS. Worldwide the technology stands to make an even bigger impact; in India for example there are 45,000 deaths per year from oral cancer, which could be dramatically reduced by the introduction of a low-cost early detection method. 
URL http://www.dielectrophoresis.net
 
Title 3DEP-Research 
Description The 3DEP instrument is the culmination of many years' work to develop a device capable of assessing the electrical properties of up to 20,000 cells in 10 seconds. This has been shown to be effecting in many applications, including the discrimination between stem cells with different differentiation fates; detection of drug-induced changes in cancer cells as a new mechanism for drug discovery; and the study of circadian rhythms in cells with no gene expression, such as red blood cells. 
Type Therapeutic Intervention - Medical Devices
Current Stage Of Development Refinement. Non-clinical
Year Development Stage Completed 2014
Development Status Under active development/distribution
Impact 3DEP devices have been sold to labs in the UK, USA and France, and are starting to make inroads into research areas across the cell biology spectrum. 
URL http://www.deptech.com
 
Title Enhanced dielectrophoretic analysis assays 
Description As a result of this project, several new streams of applications have deen developed for dielectrophoretic cell analysis, including drug ction detection and cancer screening. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2013 
Impact At the moment systems have been sold to 3 countries (US, UK and France) within the first year of production