Label-free Autofluorescence-detected Mid-ir Photothermal Microscopy

Razumtcev, Aleksandr

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https://hdl.handle.net/2142/116605 Copy

Description

Title

Label-free Autofluorescence-detected Mid-ir Photothermal Microscopy

Author(s)

Razumtcev, Aleksandr

Contributor(s)

Simpson, Garth

Issue Date

2022-06-22

Keyword(s)

Coblentz Special Session

Abstract

The instrumentation and methods to perform autofluorescence-detected photothermal mid-IR (AF-PTIR) microscopy are demonstrated experimentally and applied for chemically-selective label-free imaging of an active pharmaceutical ingredient (API) within a mixture with common pharmaceutical excipients. In AF-PTIR, the heat released from mid-IR absorption induces changes in two-photon excited UV-fluorescence (TPE-UVF) intensity. The spectral dependence of the fluorescence modulation locally informs on chemical composition with a spatial resolution dictated by the diffraction limit of visible light. AF-PTIR is shown to provide an additional level of selectivity in nonlinear optical imaging by mid-IR spectroscopy enabling mapping of the API distribution in the presence of TPE-UVF and second harmonic generation active excipients (\textbf{Fig. 1}). AF-PTIR provides high selectivity and sensitivity in image contrast for aromatic APIs, complementing broadly applicable commercial methods such as optical photothermal mid-IR (O-PTIR) microscopy. \begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.2]{figure_abstract.eps} \end{wrapfigure} \textbf{Figure 1}. (a), (c – f) – Bright field, second harmonic generation (SHG), TPE-UVF, AF-PTIR and O-PTIR images of the field of view respectively. (b) – Segmentation results showing the spatial distribution of individual components (lactose particles are shown in blue, indomethacin in green, TiO$_{2}$ in yellow and Mg stearate is shown in red).

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Handle URL

https://hdl.handle.net/2142/116605

DOI

https://doi.org/10.15278/isms.2022.WE04

Copyright and License Information

Copyright 2022 held by the authors

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