Genetically Encoding Stimulated Raman-Scattering Probes for Cell Imaging Using Infrared Fluorescent Proteins

Area of Science:

• Biophotonics
• Molecular Imaging
• Cell Biology

Background:

• Stimulated Raman scattering (SRS) microscopy offers high specificity and multiplexing potential for cell imaging.
• Current SRS techniques lack genetically encodable probes, limiting their application compared to fluorescent proteins.
• Development of endogenous tags is crucial for advancing SRS-based biological research.

Purpose of the Study:

• To introduce genetically encodable probes for SRS microscopy.
• To demonstrate the utility of infrared fluorescent proteins (IRFPs) as SRS probes.
• To enable Raman-based imaging of cellular structures using genetically encoded tags.

Main Methods:

• Utilized infrared fluorescent proteins (IRFPs) as genetically encoded probes.
• Applied near-infrared exciting pulses to leverage the electronic preresonant SRS enhancement effect.
• Performed SRS imaging of the nucleus in mammalian cells by fusing an IRFP to histone proteins.

Main Results:

• IRFPs function as effective genetically encoded SRS probes.
• Achieved SRS enhancement comparable to synthetic dyes using IRFPs.
• Successfully demonstrated SRS imaging of the nucleus with genetically encoded IRFP-tagged histone proteins.

Conclusions:

• Infrared fluorescent proteins (IRFPs) provide a viable solution for genetically encoded SRS probes.
• This breakthrough enables Raman-based cell imaging with endogenous tags.
• Future work should focus on improving photostability and expanding the vibrational palette for SRS imaging.