Precision Molecular Engineering of Compact Near-Infrared Fluorophores.

Area of Science:

• Organic Chemistry
• Biophysics
• Materials Science

Background:

• Near-infrared (NIR) fluorophores are essential for advanced bioimaging and biosensing.
• Existing methods for reducing fluorophore size often compromise NIR emission properties.
• There is a need for smaller, efficient NIR fluorophores for in vivo applications.

Purpose of the Study:

• To design and synthesize compact, single-benzene-based NIR fluorophores.
• To achieve NIR emission with reduced molecular weight.
• To explore the environmental sensitivity of novel fluorophores for bioimaging applications.

Main Methods:

• Utilized quantum chemical calculations for fluorophore design.
• Employed structure-property relationship analysis for iterative design.
• Synthesized and characterized novel single-benzene-based fluorophores.
• Investigated fluorophore emission in aqueous and lipid environments.

Main Results:

• Developed compact NIR fluorophores with emissions up to 759 nm.
• Achieved molecular weights as low as 192 g/mol (approx. 50% of Cy7).
• Demonstrated environmental sensitivity: nonemissive in water, highly emissive in lipids.
• Showcased utility in wash-free live-cell imaging.

Conclusions:

• Established a precision engineering approach for compact NIR fluorophores.
• Novel fluorophores offer significant advantages in size and imaging capabilities.
• Environmental sensitivity enables new possibilities for wash-free cellular imaging.