Fluorescence-Detected Mid-Infrared Photothermal Microscopy

We demonstrate instrumentation and methods to enable fluorescence-detected photothermal infrared (F-PTIR) microscopy, then demonstrate the utility of F-PTIR to characterize the composition within phase-separated domains of model amorphous solid dispersions (ASDs) induced by water sorption. In F-PTIR...

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Bibliographic Details
Main Authors:	Li, Minghe, Razumtcev, Aleksandr, Yang, Ruochen, Liu, Youlin, Rong, Jiayue, Geiger, Andreas C, Blanchard, Romain, Pfluegl, Cristian, Taylor, Lynne S, Simpson, Garth J
Format:	Journal Article
Language:	English
Published:	06-04-2021
Subjects:	Physics - Chemical Physics
Online Access:	Get full text
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Summary:	We demonstrate instrumentation and methods to enable fluorescence-detected photothermal infrared (F-PTIR) microscopy, then demonstrate the utility of F-PTIR to characterize the composition within phase-separated domains of model amorphous solid dispersions (ASDs) induced by water sorption. In F-PTIR, temperature-dependent changes in fluorescence quantum efficiency are shown to sensitively report on highly localized absorption of mid-infrared radiation. The spatial resolution with which infrared spectroscopy can be performed is dictated by fluorescence microscopy, rather than the infrared wavelength. Following proof of concept F-PTIR demonstration on model systems of polyethylene glycol (PEG) and silica gel, F-PTIR enabled the characterization of chemical composition within inhomogeneous ritonavir / polyvinylpyrrolidone-vinyl acetate (PVPVA) amorphous dispersions. Phase separation is implicated in the observation of critical behaviors in ASD dissolution kinetics, with the results of F-PTIR supporting the formation of phase-separated drug-rich domains upon water absorption in spin-cast films.
DOI:	10.48550/arxiv.2104.02900