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Professor Stefan Andersson-Engels *SPIE, IPIC, Tyndall National Inst, Dept Physics, UCC, Cork, Ireland

Event Date: 
Monday, November 6, 2017 - 3:30pm to 4:30pm

Upconverting Nanoparticles Provides Means for Deep-Tissue Optical Imaging and Photoactivation

Upconverting nanoparticles are gaining increasingly interest as contrast agents for optical bioimaging and also for photoactivation [1-2]. There are many reasons behind such research attention, including autofluorescence-free imaging within the tissue optical window, and improved spatial resolution as compared to conventional fluorescence-based contrast agents. One of the remaining limitations is though that they have fairly low quantum yield, which we partly can be overcome by utilizing pulsed excitation of appropriate pulse-length and duty-cycle.

In this presentation we will discuss a few aspects related to the use of upconverting nanoparticles for certain types of photoactivation. Such activation may require blue or violet excitation. Light at such wavelengths do only penetrate tissue to a submillimeter depth, while NIR excitation light of upconverting nanoparticles provide the means to locally convert NIR to blue light. This can be employed in PDT as well as in optogenetics [3].

[1] C.T. Xu, Q.Q. Zhan, H.C. Liu, G. Somesfalean, J. Qian, S.L. He, S. Andersson-Engels, Upconverting nanoparticles for pre-clinical diffuse optical imaging, microscopy and sensing: Current trends and future challenges, Laser & Photonics Reviews 7, 663-697 (2013)

[2] H. Söderlund, M. Mousavi, H. Liu, S. Andersson-Engels, Increasing depth penetration in biological tissue imaging using 808-nm excited Nd3+/Yb3+/Er3+-doped upconverting nanoparticles,  Journal of Biomedical Optics 20, 086008 (2015)

[3] A. Bansal, H. Liu, M.K.G. Jayakumar, S. Andersson-Engels, Y. Zhang, Quasi-Continuous Wave Near-Infrared Excitation of Upconversion Nanoparticles for Optogenetic Manipulation of C. elegans, Small (in press).

Prof Stefan Andersson-Engels is an expert in biomedical optics applications, with 30 years’ experience in areas from theoretical modelling of light propagation in tissue to clinical translation and commercial uptake. He is newly recruited to IPIC from heading the biophotonics activity at Lund University, being the director of the Medical Laser Centre and deputy head of Division of Atomic Physics there. His primary reason to join IPIC was to maximize the chances to assist patients in developing biomedical instruments based on photonics, bringing fundamental research to the clinic. His work has so far resulted in three spin-off companies. He has from the role in Lund, collaborated widely with researchers from all across the world. He is a recipient of an SFI Research Professorship award, and leads through this programme a team of nearly 20 researchers.

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