Friday, June 9, 2023
5 King's College Road
Professor Mohammad E. Khosroshahi
Nanobiophotonics & Biomedical Research Laboratory, MIS-Electronics Inc.
Plasmon-enhanced Fluorescence Induced Stimulated Raman Scattering as Non-destructive Non-linear Optical Method in Nanobiosensing and Bioimaging
This work describes the generation and observation of multi-wavelengths due to stimulated Raman scattering (SRS) from deep red to near-infrared (NIR) induced by plasmon-enhanced fluorescence (PEF) of fluorescein isothiocyanate (FITC) conjugated gold nanoparticles (F-AuNP). The plasmonic solution was excited by a 488 nm diode laser and the PEF due to overlapping of FITC, and localized surface plasmon resonance (LSPR) of AuNP resonance peaks provided an efficient coupling between the near-field of LSPR of AuNPs as a nano-antenna and the molecules followed by an enhanced emission. Resonance Rayleigh scattering and PEF conditions are both satisfied. PEF acts as Stokes radiation and secondary pump beam for further optical excitation within the medium. Longer wavelengths with higher output power and shorter wavelengths with lower are detected at varying angles. Time-resolved PEF spectroscopy revealed the effect of enhanced emission followed by its quenching. In addition, F-AuNPs were incubated and taken up by the king oyster mushroom (KOM) grown in the lab studied by phase contrast microscope (PCM) and fluorescence microscope (FM). The results showed PEF and SRS visible colors within the mycelium hyphae. Therefore, it is concluded that non-linear optical mechanisms can be utilized for non-destructive biomedical applications such as invitro and in vivo contrast-enhanced fluorescence sensing and nano-bioimaging of cells and tissues as monitoring techniques.
Professor Mohammad E. Khosroshahi received his Ph.D. in Applied Physics (Application of Lasers in Medicine) from Hull University (UK) in 1993 with the thesis on ophthalmological tissue ablation with tunable mid-IR and excimer lasers in collaboration with Moorefields hospital in London. He joined the Biomaterial and Tissue Engineering group of the Faculty of Biomedical Engineering at Amirkabir University of Technology (AUT) in Tehran where he was a Full Professor. He has been the Director of AUT Laser and Optics Research Center, Associate Dean of Research, and Chair of Biomaterial Group. In 2013, he joined the University of Toronto, Department of Mechanical & Industrial Engineering (MIE) as a Visiting Professor working on ‘’Contrast-enhanced photoacoustic imaging of Tumor’’ at the Center for Advanced Diffusion-Wave and Photoacoustic Technologies (CADIPT). He then continued as a research associate at CADIPT working on the contrast-enhanced imaging of blood and became the faculty adjunct Professor in 2018.
Professor Khosroshahi is the author of two books: Laser Applications in Medicine, and Applications of Biophotonics and Nanobiomaterials in Biomedical Engineering, and co-author of two book chapters on Laser surface modification of titanium alloys as biomedical implants. He has published 110 peer-reviewed papers and has 2 patents and patent-pending related to nanobiosensors. His main research interests are Nanobiophotonics, Nanomedicine, Multifunction nanostructures, Targeted drug delivery, Targeted photothermal therapy, Guided bioimaging, biological chaos, Cancer thermodynamics, Optical detection of dental decay, Photoacoustic and Photothermal characterization. Currently, Professor Khosroshahi is Director of the Nanobiophotonics and Biomedical Research Lab at MIS-Electronics in Richmond Hill where he is working on the development of novel colloidal and substrate nanobiosensors based on the Plasmon-enhanced fluorescence spectroscopy (PEFS) and Enhanced-surface-enhanced Raman scattering (E-SERS) for targeted detection of breast cancer biomarkers such as HER-II and CA 15-3, dual-mode guided bioimaging, fluorescence microscopy, and contrast phase microscopy. He is a member of the Editorial Board of the Journal of Nanomedicine and Nanotechnology, a fellow member of the Institute of Nanotechnology, a member of the Canadian Association of Physics, Canadian Medical and Biological Engineering Society, Optical Society of America, and SPIE.