NIR-emitting benzene-fused oligo-BODIPYs for bioimaging

Area of Science:

• Organic Chemistry
• Biophotonics
• Materials Science

Background:

• Near-infrared (NIR) fluorophores are crucial for biophotonics due to enhanced tissue penetration and reduced scattering.
• The current availability of NIR fluorophores is limited, hindering broader applications.
• Oligo-BODIPY dyes offer a promising scaffold for developing novel NIR-emitting molecules.

Purpose of the Study:

• To synthesize and characterize novel benzene-fused oligo-BODIPY dyes with NIR fluorescence.
• To investigate the photophysical properties of hexameric (H) and octameric (O) oligo-BODIPY forms.
• To demonstrate the utility of these NIR fluorophores in biophotonics applications, including imaging and microrheology.

Main Methods:

• Synthesis of hexameric (H) and octameric (O) benzene-fused oligo-BODIPYs.
• Spectroscopic analysis to determine excitation and emission maxima, and solvent polarity effects.
• NIR video particle tracking (NIR-VPT) for microrheology studies in F-actin networks.

Main Results:

• Achieved bright NIR fluorescence with emission maxima at 943/1075 nm (H) and 976/1115 nm (O).
• Demonstrated excitation in the NIR (921 nm for H, 956 nm for O) and broad visible range.
• Observed concentration-dependent spectral shifts and solvent-dependent emission shifts up to 20 nm.
• Successfully applied as NIR ink for remote macroscopic imaging and in NIR-VPT for biopolymer network analysis without photodamage.

Conclusions:

• Developed novel oligo-BODIPY dyes with potent NIR fluorescence properties.
• These dyes exhibit tunable spectral characteristics and are suitable for remote imaging.
• Demonstrated their value in biophotonics, particularly in microrheology, offering a photostable alternative to visible fluorophores.