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Published September 2019 | Supplemental Material + Accepted Version
Journal Article Open

High-resolution, high-contrast mid-infrared imaging of fresh biological samples with ultraviolet-localized photoacoustic microscopy

Abstract

Mid-infrared (MIR) microscopy provides rich chemical and structural information about biological samples, without staining. Conventionally, the long MIR wavelength severely limits the lateral resolution owing to optical diffraction; moreover, the strong MIR absorption of water ubiquitous in fresh biological samples results in high background and low contrast. To overcome these limitations, we propose a method that employs photoacoustic detection highly localized with a pulsed ultraviolet laser on the basis of the Gr√ľneisen relaxation effect. For cultured cells, our method achieves water-background suppressed MIR imaging of lipids and proteins at ultraviolet resolution, at least an order of magnitude finer than the MIR diffraction limits. Label-free histology using this method is also demonstrated in thick brain slices. Our approach provides convenient high-resolution and high-contrast MIR imaging, which can benefit the diagnosis of fresh biological samples.

Additional Information

© 2019 Springer Nature Publishing AG. Received 10 October 2018; Accepted 09 April 2019; Published 13 May 2019. Data availability: The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request. Code availability: The code that supports the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request. The authors thank M. Pleitez and T. Imai for helping with the system set-up and discussion, J. Ballard for editing of the manuscript and K. Briggman for helpful discussions. Certain commercial equipment, instruments and materials are identified in this paper to specify the experimental procedure adequately; this is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. This work was sponsored by National Institutes of Health grants DP1 EB016986 (NIH Director's Pioneer Award), R01 CA186567 (NIH Director's Transformative Research Award), U01 NS090579 (NIH BRAIN Initiative) and U01 NS099717 (NIH BRAIN Initiative). Author Contributions: J.S., K.M. and L.V.W. designed the experiment. J.S., T.T.W.W., Y.H. and R.Z. contributed to the system construction. J.S. and T.T.W.W. prepared the brain slices. Y.H. prepared the cell culture. C.S.Y. and J.H. designed and prepared the CNT pattern on a MgF_2 substrate. L.L. helped with LFB staining. J.S., K.M., T.T.W.W., Y.H. and L.L. were involved in discussions. J.S. performed the experiment and data analysis. L.V.W supervised the project. All authors were involved in manuscript preparation. Competing interests: L.V.W. and K.M. have financial interests in Microphotoacoustics, Inc., CalPACT, LLC and Union Photoacoustic Technologies, Ltd, which did not support this work.

Attached Files

Accepted Version - nihms-1526731.pdf

Supplemental Material - 41566_2019_441_MOESM1_ESM.pdf

Supplemental Material - 41566_2019_441_MOESM2_ESM.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 20, 2023