Fig. 2: Imaging sagittal sections of embryonic and adult zebrafish shown in false-color compositions of key IR absorption bands.

Embryonic zebrafish prepared at 28, 52, 76, 100, and 124 h post fertilization were imaged using (a) the presented IR-LSM instrument equipped with 20×/0.8 NA magnification, and (b) brightfield microscopy of H&E-stained sections of similarly prepared samples at the same stage. c Adult female zebrafish organ imaging was demonstrated with high-resolution insets of the (i) brain, (ii) gills, and (iii) ovary with the whole fish image presented in (d) and (e) fingerprint region spectra, at locations indicated by the pin symbol (from top to bottom), of tail muscle (navy), intestine (orange), liver (gold), cerebellum (purple), lamellar artery (green), primary growth stage I oocyte (teal) with germinal vesicle (burgundy), a small stage I oocyte (black), and degenerated oocyte (gray). f Contamination of PTFE microplastics in the zebrafish tissue sample with the Amide I absorbance band shown (grayscale) and detected PTFE signature at masked at 1213 cm⁻¹ and false-colored (green).