Chinese Optics Letters, Volume. 23, Issue 7, 071701(2025)
Vascular permeability assessment using dual-wavelength photoacoustic microscopy with spectral unmixing
Fig. 1. Verification of spectral unmixing in phantom experiments. (a) Photograph of the in vitro phantom, displaying a plastic tube containing a mixture of blood and EB. (b) Absorption spectra of blood and EB. (c) Photoacoustic images of the phantom acquired at wavelengths of 532 and 610 nm. Scale bars = 400 µm. (d) Results of spectral unmixing, illustrating the separation of hemoglobin and EB signals in the mixtures. Scale bars = 300 µm. (e) Linear correlation between the photoacoustic signal intensity and EB concentration.
Fig. 2. Schematic diagram and performance testing of dual-wavelength PAM. (a) Schematic diagram of the dual-wavelength PAM system. CL, convex lens; PH, pinhole; DM, dichroic mirror; HWP, half-wave plate; FC, fiber coupler; SMF, single-mode fiber; NBF, narrow-bandpass filter; OL, objective lens; CorrL, correction lens; UT, ultrasound transducer; WT, water tank; AMP, amplifier; DAQ, data acquisition unit; PC, computer. (b) Photoacoustic image of a surgical blade, scale bar = 50 µm. (c) Scanning results of the sharp edges of the surgical blade. Selected B-scan images and their corresponding edge diffusion functions demonstrate lateral resolutions of 8.06 µm at 532 nm and 14.23 µm at 610 nm.
Fig. 3. Morphological alterations in the liver and kidney. Images of liver vasculature at 532 nm in (a) normal and (b) fibrotic mice (1-week model). PAM images of kidney vasculature at 532 nm in (c) normal and (d) UUO-treated fibrotic mice (1-week model). Scale bars = 200 µm for (a) and (b), and 100 µm for (c) and (d). (e) Quantitative analysis of vascular networks in the liver. (f) Quantitative analysis of vascular networks in the kidney. Statistical significance was assessed using a two-tailed unpaired Student’s t-test; *p < 0.05, **p < 0.01. Data are presented as mean ± SD (n = 3 per group).
Fig. 4. Time-lapse PAM imaging of liver EB extravasation. EB leakage in (a) normal and (b) fibrotic mice over a 15 min period post-injection. Scale bars = 100 µm. (c) Statistical comparison of EB dynamics. (d) Changes in hemoglobin concentration (CHb) due to fibrosis, analyzed through pixel comparisons. (e) EB extravasation at 15 min post-injection in control versus liver fibrosis groups. Statistical significance was assessed with a two-tailed unpaired Student’s t-test; **p < 0.01, ***p < 0.001. Data presented as mean ± SD (n = 3 per group).
Fig. 5. Time-lapse PAM imaging of kidney EB extravasation. EB leakage in the microvasculature of (a) normal and (b) UUO mice over 15 min post-injection. Scale bars = 100 µm. (c) Statistical comparison of EB dynamics. (d) Changes in CHb due to fibrosis analyzed by pixel comparisons. (e) EB extravasation at 15 min post-injection in control versus UUO mice. Statistical significance was assessed with a two-tailed unpaired Student’s t-test; **p < 0.05. Data are presented as mean ± SD (n = 3 per group).
Fig. 6. Histopathological analysis of liver and kidney fibrosis. (a) Representative photomicrographs of liver tissues stained with hematoxylin-eosin and Masson’s trichrome. (b) Representative photomicrographs of kidney tissues stained with hematoxylin-eosin and Masson’s trichrome. Scale bars = 200 µm.
Get Citation
Copy Citation Text
Yongyan Ren, Kun Yu, Qiansong Xia, Honghui Li, Liming Nie, "Vascular permeability assessment using dual-wavelength photoacoustic microscopy with spectral unmixing," Chin. Opt. Lett. 23, 071701 (2025)
Category: Biophotonics
Received: Jan. 25, 2025
Accepted: Mar. 17, 2025
Posted: Mar. 17, 2025
Published Online: Jun. 20, 2025
The Author Email: Honghui Li (lihonghui@gdph.org.cn), Liming Nie (limingnie@gmail.com)