Fig. 6: Tissue penetration of NIR-II dyes over NIR-I dyes.
From: Low molecular weight 4,4’-quinocyanines for in vivo NIR-II fluorescence imaging
Fluorescence penetration of NIR-I (ICG, JAS239, IRDye 800) and NIR-II (JAM317, JAM318, JAM319, JAP331, JAP334) dyes through A increasing depth of intralipid solution (0–6 mm) and B increasing chicken tissue thickness (0–6 mm). NIR-I dyes were imaged under standard NIR-I excitation, while NIR-II dyes were imaged using a 940 nm laser and under either a long-pass (LP) 1000 or 1250 nm filters C Normalized quantification of (B) fluorescence intensity through chicken tissue phantom for NIR-I and NIR-II dyes imaged with an LP 1000 nm filter. NIR-II dyes exhibit superior depth penetration compared to NIR-I dyes at all thicknesses, with higher fluorescence retention at increased depths. Fluorescence signals from NIR-I dyes rapidly attenuate even at 2 mm, whereas NIR-II dyes maintain 50% intensity up to 6 mm. D Schematic of the experimental laser excitation and detector collection setup used to quantify fluorescence depth penetration through tissue-mimicking phantoms.
