Preparation of NIR-II Polymer Nanoprobe Through Twisted Intramolecular Charge Transfer and Förster Resonance Energy Transfer of NIR-I Dye

Adv Healthc Mater. 2024 Sep;13(22):e2400760. doi: 10.1002/adhm.202400760. Epub 2024 May 4.

Abstract

Near-infrared-II (NIR-II) fluorescence imaging is pivotal in biomedical research. Organic probes exhibit high potential in clinical translation, due to advantages such as precise structure design, low toxicity, and post-modifications convenience. In related preparation, enhancement of NIR-II tail emission from NIR-I dyes is an efficient method. In particular, the promotion of twisted intramolecular charge transfer (TICT) of relevant NIR-I dyes is a convenient protocol. However, present TICT-type probes still show disadvantages in relatively low emission, large particle sizes, or limited choice of NIR-I dyes, etc. Herein, the synthesis of stable small-sized polymer NIR-II fluoroprobes (e.g., 7.2 nm), integrating TICT and Förster resonance energy transfer process to synergistically enhance the NIR-II emission is reported. Strong enhanced emissions can be obtained from various NIR-I dyes and lanthanide elements (e.g., twelvefold at 1250 nm from Nd-DTPA/IR-808 sample). The fluorophore provides high-resolution angiography, with high-contrast imaging on middle cerebral artery occlusion model mice for distinguishing occlusion. The fluorophore can be rapidly excreted from the kidney (urine ≈65% within 4 h) in normal mice and exhibits long-term renal retention on acute kidney injury mice, showing potential applications in the prognosis of kidney diseases. This development provides an effective strategy to design and synthesize effective NIR-II fluoroprobes.

Keywords: FRET (Förster resonance energy transfer); TICT (twisted intramolecular charge transfer); enhanced tail emission; nir‐ii angiography; nir‐ii nephrography.

MeSH terms

  • Animals
  • Fluorescence Resonance Energy Transfer* / methods
  • Fluorescent Dyes* / chemistry
  • Infarction, Middle Cerebral Artery / diagnostic imaging
  • Mice
  • Nanoparticles / chemistry
  • Polymers* / chemistry

Substances

  • Fluorescent Dyes
  • Polymers