Currently, only a few
18
F-radiolabeling methods were conducted in aqueous media, with non-macroelement fluoride acceptors and stringent conditions required. Herein, we describe a one-step non-solvent-biased, room-temperature-driven
18
F-radiolabeling methodology based on organophosphine fluoride acceptors. The high water tolerance for this isotope-exchange-based
18
F-labeling method is attributed to the kinetic and thermodynamic preference of F/F over the OH/F substitution based on computational calculations and experimental validation. Compact [
18/19
F]di-
tert
-butyl-organofluorophosphine and its derivatives used as
18
F-labeling synthons exhibit excellent stability in vivo. The synthons are further conjugated to several biomolecular ligands such as c(RGDyk) and human serum albumin. The one-step labeled biomolecular tracers demonstrate intrinsic target imaging ability and negligible defluorination in vivo. The current method thus offers a facile and efficient
18
F-radiolabeling pathway, enabling further widespread application of
18
F.
Although
photoacoustic imaging (PAI) in the second near-infrared
(NIR-II) region (1.0–1.7 μm) is admired for deeper penetration
and higher contrast, few organic NIR-II absorbers are available as
exogenous contrast agents in vivo. A1094 belongs to the very few ∼1.1
μm absorbing croconaine dyes that have superior extinction coefficient
and tend to form irregular aggregation. In this study, shape-controlled
A1094@DSPE-PEG2000 micelles with a J-aggregate core with
remarkable 1.2–1.3 μm absorption are fabricated as biocompatible
organic agents. Excellent capabilities in photothermal conversion,
photostability, and PAI are found in in vitro studies. In vivo PAI
of inguinal lymph nodes and in situ glioma pre- and post-resection,
all demonstrate high lymph/tumor-targeting efficiency. An ∼4.54
mm deep brain lesion is imaged at 1200 nm with minimized background
and increased contrast compared to 970 nm. Overall, we achieved significant
bathochromic shift of organic absorbers and expanded their PAI application
to the long-wavelength end of the NIR-IIa region.
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