Eric Strohm

Post Doctoral Fellow
Supervisor: Dr. Michael Kolios

Profile picture - Eric Strohm
KHE233
350 Victoria Street Toronto, Ontario, Canada M5B 2K3
estrohm@ryerson.ca

Specialization

Characterization of single cells using high frequency ultrasound and photoacoustic methods

Research Projects

Ultrasound and photoacoustic measurements
High frequency ultrasound and photoacoustic methods can be used to probe single cells for the purpose of identifying the cell type by extracting their intrinsic physical properties. This can be used to identify tumor cells in a blood or tissue sample, and differentiate cell types such as red blood cells and white blood cells. When cells are irradiated with ultrasound that has a wavelength similar to the size of the cell (frequencies over 100 MHz), the scattered ultrasound signal is encoded with unique signatures based on the properties of that cell. Through signal processing methods, the size, shape, composition and microstructure of the cell can be extracted from the signal power spectrum. When irradiated with a laser, the cell absorbs the laser energy and emits a photoacoustic pressure wave that can be measured using ultrasound hardware. Like ultrasound, the photoacoustic signal is encoded with unique information based on the properties of that cell. However for photoacoustic signals to be generated, the cell must absorb the laser energy, and that depends on the absorption properties of the cell. By using specific dyes with varying optical absorption profiles, different components of the cell can be targeted (such as the nucleus, cytoplasm and organelles); the resulting photoacoustic signals carry unique information about those structures. We are currently using these methods to detect hematological malignancies and circulating tumor cells in blood samples.

Theoretical models
Numerical simulations, finite element models and analytical solutions of equations are used to solve physical problems such as interactions of ultrasound and photoacoustic waves with cells, particularly from asymmetric or heterogeneous particles such as red blood cells. These models help visualize wave propagation and understand their underlying physical mechanisms. Comparing the measured signals to theoretical models allows extraction of specific cellular parameters such as the size, shape and sound speed to aid in specific cell identification.

Selected Publications

Book chapters (1)
1. E.M. Strohm, G. Czarnota, M.C. Kolios, “Acoustic microscopy of cells” in Quantitative Ultrasound of Soft Tissue, J. Mamou and M. Oelze (Eds.). Springer, 2013.

Publications in refereed journals (5)
1. E.M. Strohm, E. Berndl, M.C. Kolios, “High frequency label-free photoacoustic microscopy of single cells”, Photoacoustics, 1(3), 2013, pp. 49-53.
2. E.M. Strohm, E. Berndl, M.C. Kolios, “Probing red blood cell morphology using high frequency photoacoustics,” Biophysical Journal, 105(1), 2013, pp. 59-67.
*** Featured by journalists in Scientific American, New Scientist, Nature Highlights and ScienceNOW.
3. E.M. Strohm, I. Gorelikov, N. Matsuura, M.C. Kolios, “Acoustic and photoacoustic characterization of micron-sized perfluorocarbon emulsions”, Journal of Biomedical Optics, 17(9), 2012, pp. 096016-26.
4. E.M. Strohm, M. Rui, I. Gorelikov, N. Matsuura, M.C. Kolios, “Vaporization of perfluorocarbon droplets using optical irradiation”, Biomedical Optics Express, 2(6), 2011, pp. 1432-1442.
5. E.M. Strohm, G. Czarnota, M.C. Kolios “Quantitative Measurements of Apoptotic Cell Properties Using Acoustic Microscopy”, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 57(10), 2010, pp. 2293-2304.

Publications in conference proceedings (19)
1. E.M. Strohm, E. Berndl, M.C. Kolios, “Circulating tumor cell detection using photoacoustic spectral methods”, SPIE Proceedings 2014.
2. Y.J. Wang, E.M. Strohm, Y. Sun, C. Niu, Y. Zheng, Z. Wang, M.C. Kolios, “PLGA/PFC particles loaded with gold nanoparticles as dual contrast agents for photoacoustic and ultrasound imaging”, SPIE Proceedings 2014.
3. F. Kibria, E. Hysi, E.M. Strohm, M.C. Kolios, “Identification of red blood cell rouleaux formation using photoacoustic ultrasound spectroscopy”, SPIE Proceedings 2014.
4. Y. Sun, C. Niu, Y.J. Wang, E.M. Strohm, Y. Zheng, H. Ran, Z. Wang, M.C. Kolios, “Vaporization, photoacoustic and acoustic characterization of PLGA/PFH particles loaded with optically absorbing materials”, Proceedings of the 2013 IEEE International Ultrasonics Symposium.
5. E.M. Strohm, and M.C. Kolios. “Sound Speed Estimation in Single Cells Using the Ultrasound Backscatter Power Spectrum.” In ICA 2013 Montreal, 19:075012. Montreal, Canada: ASA, (oral, June 3, 2013).
6. E.S. Berndl, L. Wirtzfeld, E.M. Strohm, M.C. Kolios. “Acoustical Imaging of Internal Spheroid Structures for a Series of Frequencies.” In ICA 2013 Montreal, 19:075086. Montreal, Canada: ASA, 2013.
7. M.C. Kolios, E.S. Berndl, L. Wirtzfeld, E.M. Strohm, and G.J. Czarnota. “Acoustic and Photoacoustic Imaging of Spheroids.” In ICA 2013 Montreal, 19:075075. Montreal, Canada: ASA, 2013.
8. M.M. Pasternak, E.M. Strohm, and M.C. Kolios. “An Analysis of the Acoustic Properties of the Cell Cycle and Apoptosis in MCF-7 Cells.” In ICA 2013 Montreal, 19:075014. Montreal, Canada: ASA, 2013.
9. E.M. Strohm, E. Berndl, M.C. Kolios, “A photoacoustic technique to measure the properties of single cells”, SPIE Proceedings 2013.
10. E.M. Strohm, E. Hysi, M.C. Kolios, “Photoacoustic measurements of single red blood cells” Proceedings of the 2012 IEEE International Ultrasonics Symposium.
11. E.M. Strohm, I. Gorelikov, N. Matsuura, M.C. Kolios, “Photoacoustic spectral characterization perfluorocarbon droplets”, SPIE Proceedings 2012.
12. E.M. Strohm and M.C. Kolios, “Sound velocity and attenuation measurements of perfluorocarbon droplets using photoacoustic methods”, Proceedings of the 2011 IEEE International Ultrasonics Symposium.
13. E.M. Strohm, M. Rui, I. Gorelikov, N. Matsuura, M.C. Kolios, “Photoacoustic characterization of micron-sized perfluorocarbon droplets”, SPIE Proceedings 2011.
14. E.M. Strohm, I. Gorelikov, N. Matsuura, M.C. Kolios, “Optical droplet vaporization: photoacoustic characterization of micron-sized perfluorocarbon droplets”, Proceedings of the 2010 IEEE International Ultrasonics Symposium.
15. E.M. Strohm, M. Rui, M. Pasternak, M. Mercado, G. Czarnota, M.C. Kolios, “A comparison of the ultrasonic properties of cells during apoptosis and mitosis using acoustic microscopy”, Proceedings of the 2010 IEEE International Ultrasonics Symposium.
16. E.M. Strohm, M.C. Kolios, “Measuring scattering in apoptotic cancer cells using ultra high frequency acoustic microscopy”, Acoustics Week in Canada, 2009.
17. E.M. Strohm, M.C. Kolios, “Quantifying ultrasonic properties of cells during apoptosis using time resolved acoustic microscopy”, Proceedings of the 2009 IEEE International Ultrasonics Symposium.
18. S. Brand, E.M. Strohm, M.C. Kolios, K. Raum, “Signal Analysis For Estimating Mechanical Properties of Viable Cells Using Acoustic GHz Microscopy”, Proceedings of the 2009 IEEE International Ultrasonics Symposium.
19. E.M. Strohm, M.C. Kolios, “Measuring the Mechanical Properties of Cells using Acoustic Microscopy”, Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009.

Website

scholar.google.ca/citations?user=jyVZHmEAAAAJ&hl=en

Professional Memberships

Institute of Electronic and Electrical Engineers (IEEE), 2009-present
Society of Photo-Optical Instrumentation Engineers (SPIE), 2010-present

Curriculum Vitae



LinkedIn

http://www.linkedin.com/in/ericstrohm