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

Published

May 13, 2019

Author(s)

Junhui Shi, Terrence Wong, Yun He, Lei Li, Ruiying Zhang, Christopher Yung, Jeeseong C. Hwang, Lihong Wang

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 (UV) laser on the basis of the Grüneisen relaxation effect. For cultured cells, our method achieves water-background free MIR imaging of lipids and proteins at UV 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 diagnosis of fresh biological samples.

Citation

Nature Photonics

Volume

13

Pub Type

Journals

Keywords

photoacoustic, microscopy

Citation

Shi, J. , Wong, T. , He, Y. , Li, L. , Zhang, R. , Yung, C. , Hwang, J. and Wang, L. (2019), High-resolution, high-contrast mid-infrared imaging of fresh biological samples with ultraviolet-localized photoacoustic microscopy, Nature Photonics (Accessed October 9, 2025)