Electronic Sensors of Dielectrophoretic actuation for microfluidics based single cell diagnostics:
The dielectric response of cells offer insight into many aspects of their physiological condition. It can detect the loss of ions that occurs during programmed cell death or the uptake of ions by multidrug resistant cancer cells. For portable and low cost applications it is highly desirable to interrogate cells using an all-electronic approach. In collaboration with G. Bridges, we have demonstrated an all-electrical approach to dielectric cell diagnostics that uses a combination of (10 kHz to 10 MHz) electric fields for stimulus and capacitance (at ~1-2 GHz) for sensing. We demonstrated use of a sub-attofarad (~2 GHz microwave interferometer) differential capacitance sensor to detect single cells passing over co-planar electrodes while simultaneously dielectrophoretically actuating cells. We have theoretically and experimentally determined the fundamental limits of this approach due to the shear-induced rotation of cells (Phys.Rev.E). Using this approach we have demonstrated mechanical differentiation of cancer cells and dielectric detection of the onset of programmed cell death (apoptosis) in a bioprocess (Biomicrofluidics). As a result of this work a two-population model of bulk dielectric response that better explained the link to physiological changes (BioTech and BioEngg). This work was highlighted in the Genetic Engineering and Biotechnology News (Sept 2013, Vol. 33).
Sensors for Structural Health Monitoring of Civil Infrastructure:
We adapted instrumentation from SPM for use in the monitoring of civil structures such as bridges. We adapted a capacitance sensor for use in a novel passive wireless strain sensor and fiber optics techniques were adapted for fiber Bragg grating (FBG) strain sensors. The FBG work demonstrated the use of a gas cell reference with a swept frequency laser for a long-term frequency standard to improve the precision of FBG measurements for civil infrastructure monitoring. In collaboration with G. Bridges (Manitoba) I have pioneered several passive wireless sensors that are based on resonant RF cavities, where the resonant frequency is modulated by a measurand. The sensor can then be interrogated remotely using microwave pulse-echo techniques. We have demonstrated that the sensor that can be interrogated at a distance of 8 m with a resonant frequency resolution of less than 10 ppm. This resolution is suitable for civil monitoring applications where strain resolution of less than 10 ppm is required.
Conducting and conjugated polymer sensors and devices:
Collaborations between Thomson and Freund (Chemistry), has led to the discovery of several new approaches to fabricating electronic sensors and devices. A new electronic device based on conductivity modulation through field-induced motion of ions in conjugated polymers has been demonstrated in several proof-of-concept devices including a memory storage device. This work has been published as a communication in Advanced Materials. Thomson/Freud used this approach on a 400 nm cross-bar device in a cross bar configuration to demonstrates that the approach of electrochemically depositing the active layer after the lithographic fabrication of the cross bar is feasible. An important advantage of this system is that it is compatible with conventional CMOS electronics and requires no electrolyte. Fruend and Thomson have also collaborated on developing sensors and artificial photosynthetic systems. Conducting polymer and capacitive sensors for detection of volatile vapors and carbon dioxide from grain spoilage have been demonstrated in a laboratory setting.
Nanoprobe Measurements for Electronic Materials Analysis:
In collaboration with G.E. Bridges, I have pioneered several scanning probe techniques for integrated circuit (IC) testing. SPM: Scanning probe microscopy (SPM) has developed into a powerful set of tools for the analysis of most material properties with nanometer resolution. Our group has contributed to advances in this field for the last 20 years. Our recent contributions are the demonstration of a new method to map currents in integrated circuits and also to image high frequency phenomena such as surface acoustic waves. We have also demonstrated tip induced electric field actuation of micro-resonators with simultaneous detection via cantilever detection.
111. K. Perveen, G. E. Bridges, S. Bhadra, and D. J. Thomson, “Corrosion potential sensor for remote monitoring of civil structure based on printed circuit board sensor,” IEEE Transactions on Instrumentation and Measurement, vol. 63, no. 10, pp. 2422–2431, 2014.
110. B. Saboktakin Rizi, K. Braasch, E. Salimi, M. Butler, G. E. Bridges, and D. J. Thomson, “Monitoring the dielectric response of single cells following mitochondrial adenosine triphosphate synthase inhibition by oligomycin using a dielectrophoretic cytometer,” Biomicrofluidics, vol. 8, no. 6, 2014.
109. J. H. Zhao, D. J. Thomson, E. Murison, G. J. van Rijn, A. De Mey, and G. Mustapha, “Calibration of dielectric based moisture sensing in stone, mortar and stone-mortar sandwiches,” Journal of Civil Structural Health Monitoring, vol. 4, no. 4, pp. 277–288, 2014.
108. K. Perveen, G. E. Bridges, S. Bhadra, and D. J. Thomson, “Corrosion potential sensor for remote monitoring of civil structure based on printed circuit board sensor,” IEEE Transactions on Instrumentation and Measurement, vol. 63, no. 10, pp. 2422–2431, 2014.
107. S. Bhadra, W. Blunt, C. Dynowski, M. McDonald, D. J. Thomson, M. S. Freund, N. Cicek, and G. E. Bridges, “Fluid embeddable coupled coil sensor for wireless pH monitoring in a bioreactor,” IEEE Transactions on Instrumentation and Measurement, vol. 63, no. 5, pp. 1337–1346, 2014.
106. D. J. Thomson, “The economic case for service life extension using structural health monitoring based on reduced cost of borrowing”, Journal of Civil Structural Health Monitoring, Accepted, 3 (4), pp. 335-340, 2013 (Invited contribution from CSHMI-4 workshop)
105. K. Braasch, M. Nikolic‐Jaric, T. Cabel, E. Salimi, G.E. Bridges, D.J. Thomson, M. Butler, “The changing dielectric properties of CHO cells can be used to determine early apoptotic events in a bioprocess”, Biotechnology and bioengineering, Accepted, 110(11), pp. 2902-2914, 2013
104. M. Ghafourian, G.E. Bridges, A.Z. Nezhad, D.J. Thomson, “Wireless overhead line temperature sensor based on RF cavity resonance”, Smart Materials and Structures 22 (7), 075010, 2013
103. E. Salimi, D. Thomson, and G. E. Bridges, “Membrane dielectric dispersion in nanosecond pulsed electroporation of biological cells,” IEEE Transactions on Dielectrics and Electrical Insulation, vol. 20, no. 4, pp. 1256–1265, 2013.
102. S. Bhadra, D.J. Thomson, G.E. Bridges, “A wireless embedded passive sensor for monitoring the corrosion potential of reinforcing steel”, Smart Materials and Structures 22 (7), 075019, 2013
101. M Nikolic-Jaric, T Cabel, E Salimi, A Bhide, K Braasch, M Butler, GE Bridges and DJ Thomson, ”Differential electronic detector to monitor apoptosis using dielectrophoresis-induced translation of flowing cells (dielectrophoresis cytometry)”, Biomicrofluidics 7, Art. Num. 024101, 2013 (Was one of the 20 most downloaded articles in March 2013 and was an editors choice for 2013)
100. Iman Yahyaie, Shane Ardo, Derek R. Oliver, Douglas J. Thomson, Michael S. Freund, and Nathan S. Lewis, “Comparison Between the Electrical Junction Properties of H-terminated and Methyl-terminated Individual Si Microwire/Polymer Assemblies for Photoelectrochemical Fuel Production”, Energy & Environmental Science, Vol. 5, Iss. 12 , pp. 9789-9794, 2012
99. T. Arezoo Emadi, Cyrus Shafai, Douglas J. Thomson, Michael S. Freund, Noel D. G. White, and Digvir S. Jayas Polymer-based Chemicapacitor Sensor, for 1-Octanol and Relative Humidity Detection at Different Temperatures and Frequencies, IEEE Sensors Journal, Vol. 13, Iss. 2, pp. 519-527, Feb. 2013
98. J. H. Zhao, E. Rivera, A. Mufti and D. J. Thomson, “Evaluation of Dielectric Based and other methods for Moisture Content Measurement in Building Stones”, Journal of Civil Structural Health Monitoring, Vol. 2, Iss 3-4, pp. 137- 148, 2012
97. M. Nikolic-Jaric, S.F. Romanuik, G.A. Ferrier, T. Cabel, E. Salimi, D.B. Levin, G.E. Bridges, D.J. Thomson, “Electronic detection of dielectrophoretic forces exerted on particles flowing over interdigitated electrodes”, Biomicrofluidics, Vol. 6, Iss. 2, Art. Num. 024117, Jun. 2012
96. I. Yahyaie, D.A. Buchanan,G.E. Bridges, D.J. Thomson, D.R. Oliver, “High-Resolution Imaging of Gigahertz Polarization Response Arising From the Interference of Reflected Surface Acoustic Waves”, IEEE Trans. Ultrasonics Ferroelectrics and frequency control, Vol. 59, Iss. 6, pp. 1212-1218, Jun. 2012
95. M.E. Hossain, G.M.A. Rahman, M.S. Freund, D.S. Jayas, N.D.G. White, C. Shafai, D.J. Thomson, “Fabrication and Optimization of a Conducting Polymer Sensor Array Using Stored Grain Model Volatiles”, J. Agricultural and food chemistry, Vol. 60, Iss. 11, pp. 2863-2873, Mar. 2012
94. T. Senthilkumar; Jayas, D.S. Jayas, N.D.G. White, M.S. Freund, C. Shafai, D.J. Thomson, "Characterization of volatile organic compounds released by granivorous insects in stored wheat", J. Stored Products Research, Vol. 48, pp. 91-96, Jan. 2012
93. I. Yahyaie, K. McEleney, M.G. Walter, D.R. Oliver, D.J. Thomson, M.S. Freund, N.S. Lewis, "Characterization of the Electrical Properties of Individual p-Si Microwire/Polymer/n-Si Microwire Assemblies, J. Phys. Chem. C, Vol. 115, Iss. 50, pp. 24945-24950, Dec. 22, 2011
92. S. Bhadra, G.E. Bridges, D.J. Thomson and M.S. Fruend, "Electrode Potential-Based Coupled Coil Sensor for Remote pH Monitoring", IEEE Sensors J., Vol. 11, Iss. 11, pp. 2813-2819, Nov 2011
91. A. Mufti, D. Thomson, D. Inaudi, H. M. Vogel, and D. McMahon, "Crack detection of steel girders using Brillouin optical time domain analysis", J Civil Struct. Health Monitoring, DOI 10.1007/s13349-011-0006-8, 2011