Clickable fluorophores for biological labeling--with or without copper

Area of Science:

• Organic Chemistry
• Bioconjugation Chemistry
• Fluorescence Spectroscopy

Background:

• Click chemistry has revolutionized bioconjugation, enabling efficient and specific labeling of biomolecules.
• Development of novel fluorophores with broad spectral coverage and diverse reactivity is crucial for advanced biological imaging.
• Copper-catalyzed azide-alkyne cycloaddition (CuAAC) and copper-free click reactions offer orthogonal labeling strategies.

Purpose of the Study:

• To synthesize a novel set of clickable fluorophores with emission across the visible and near-infrared spectrum.
• To develop fluorophores compatible with both copper-catalyzed and copper-free click chemistry for versatile bioconjugation.
• To demonstrate the utility of these fluorophores in labeling biomolecules, cell surfaces, and glycans.

Main Methods:

• Synthesis of new fluorophores featuring either terminal alkynes for CuAAC or cyclooctyne moieties for copper-free click reactions.
• Characterization of spectral properties (absorption and emission) of the synthesized fluorophores.
• Application of fluorophores for labeling model biopolymer building blocks, cell surfaces, and azide-modified glycans on CHO cells.

Main Results:

• Successful synthesis of clickable fluorophores covering the visible to near-infrared spectrum.
• Demonstrated efficient labeling of biomolecules and cell surface glycans using both copper-catalyzed and copper-free click reactions.
• Versatile applicability shown in cell labeling experiments, highlighting broad utility in bioorthogonal chemistry.

Conclusions:

• The new fluorophores offer a versatile toolkit for bioorthogonal labeling across a wide spectral range.
• The developed dyes are suitable for labeling various biological targets, including complex cellular structures.
• These fluorophores are expected to find broad applications in both in vitro and in vivo imaging and labeling studies.