PMC

Structures and photophysical properties of heptamethine and pentamethine dyes. (a) Chemical structures of heptamethine and pentamethine dyes explored in this study (see for full structures). (b) Absorption maxima of ICG and dyes 1–10 displayed graphically on the electromagnetic spectrum and aligned with the distinct excitation channels used for excitation-multiplexed, single-channel SWIR imaging. (c) Absorbance spectra of newly reported dyes. (d) Emission spectra of newly reported dyes, ex. = 755 for pentamethine dyes; ex. = 885 nm for heptamethine dyes. (e, f) Quantum yields of heptamethine dyes (e) and pentamethine dyes (f) displayed graphically; error bars represent standard deviation. (g) Table of photophysical properties. See for error values.

Tissue concentrations of the dyes 24 h after injection. The liver and lung were assayed to demonstrate tissue accumulation and reticuloendothelial system uptake of the PEGylated and non-PEGylated dyes conjugated to the anti-CEA antibody. The non-PEGylated dyes in both cases accumulated to significantly higher levels than the PEGylated dyes in both the lung (; for the 650 dyes; ; for the 750 dyes) and the liver (; for the 650 dyes; ; for the 750 dyes).

(A, B, C) Decolorization of dyes by purified Lac, Lac^ep69, D500G at different time. (D) Decolorization of dyes by purified Lac and its mutants Lac^ep69 and D500G in 1 h.

Mechanism of targeting abilities. (a) LA secretion of cells under normal culture conditions (***p < 0.001). (b) Effects of glycolysis inhibitors 3-BP on LA secretion. (c) Effects of glycolysis inhibitors DCA on LA secretion. (d) Fluorescence images of MCF-7 and GNRs-PEG-TPEI incubated for different times (red: Nuclear Red LCS1 dyes the nucleus, green: DiO dyes the membrane, and blue: GNRs-PEG-TPEI dyes the negatively charged cell membrane). (e) Fluorescence images of GNRs-PEG-TPEI applied to HepG2, Caco-2, MCF-7, and NCM460 (red: Nuclear Red LCS1 dyes the nucleus, green: DiO dyes the membrane, and blue: GNRs-PEG-TPEI dyes the negatively charged cell membrane). (f) Fluorescence images of GNRs-PEG-TPEI applied to coculture of Caco-2 and NCM460 (orange-red: DiI dyes the membrane of NCM460, green: DiO dyes the membrane of Caco-2, and blue: GNRs-PEG-TPEI dyes the negatively charged cell membrane). (g) Effect of DCA on cell fluorescence imaging (red: Nuclear Red LCS1 dyes the nucleus, green: DiO dyes the membrane, and blue: GNRs-PEG-TPEI dyes the negatively charged cell membrane). Images were collected using a Plan-apochromat 63×/1.4 oil immersion objective by sequential scanning, with excitation at 405 and 488 nm. Emission was collected by photomultiplier tubes in the ranges of 423–492 and 590–700 nm, respectively.