Deep tissue optical imaging of upconverting nanoparticles enabled by exploiting higher intrinsic quantum yield through use of millisecond single pulse excitation with high peak power

Abstract

-Engels, S. (2013). Deep tissue optical imaging of upconverting nanoparticles enabled by exploiting higher intrinsic quantum yield through use of millisecond single pulse excitation with high peak power. Nanoscale, 5(20), 10034-10040. https://doi.org/10.1039/c3nr01917aRegistered Charity Number 207890 Accepted ManuscriptThis is an Accepted Manuscript, which has been through the RSC Publishing peer review process and has been accepted for publication.Accepted Manuscripts are published online shortly after acceptance, which is prior to technical editing, formatting and proof reading. This free service from RSC Publishing allows authors to make their results available to the community, in citable form, before publication of the edited article. This Accepted Manuscript will be replaced by the edited and formatted Advance Article as soon as this is available.To cite this manuscript please use its permanent Digital Object Identifier (DOI®), which is identical for all formats of publication.More information about Accepted Manuscripts can be found in the Information for Authors.Please note that technical editing may introduce minor changes to the text and/or graphics contained in the manuscript submitted by the author(s) which may alter content, and that the standard Terms & Conditions and the ethical guidelines that apply to the journal are still applicable. In no event shall the RSC be held responsible for any errors or omissions in these Accepted Manuscript manuscripts or any consequences arising from the use of any information contained in them. We have accomplished deep tissue optical imaging of upconverting nanoparticles at 800 nm, using millisecond single pulse excitation with high peak power. This is achieved by carefully choosing the pulse parameters, derived from time-resolved rateequation analysis, which result in higher intrinsic quantum yield that is utilized by upconverting nanoparticles for generating this near infrared upconversion emission. The pulsed excitation approach thus promises previously unreachable imaging depths and shorter data acquisition times compared with continuous wave excitation, while simultaneously keeping the possible thermal side-effects of the excitation light moderate. These key results facilitate means to break through the general shallow depth limit of upconverting-nanoparticle-based fluorescence techniques, necessary for a range of biomedical applications, including diffuse optical imaging, photodynamic therapy and remote activation of biomolecules in deep tissues. www.rsc.org/nanoscale

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