Polydiacetylene-based ultrastrong bioorthogonal Raman probes for targeted live-cell Raman imaging.

Area of Science:

• Chemical Biology
• Spectroscopy
• Materials Science

Background:

• Live-cell Raman imaging utilizes bioorthogonal Raman probes for distinct signals in the cellular Raman-silent region (1800–2800 cm^-1).
• Existing probes often require Raman enhancers or lack sufficient signal strength for high-quality imaging.

Purpose of the Study:

• To develop novel, water-soluble, and biocompatible polydiacetylene-based Raman probes with intrinsic ultrastrong signals.
• To enable organelle-targeting live-cell Raman imaging in the Raman-silent region without external enhancers.

Main Methods:

• Synthesis of a master polydiacetylene, poly(deca-4,6-diynedioic acid) (PDDA), via host-guest topochemical polymerization.
• Modification of PDDA to create functionalized, multi-purpose Raman probes.
• Application of modified PDDA probes for live-cell stimulated Raman scattering (SRS) imaging.

Main Results:

• PDDA exhibits significantly enhanced alkyne vibration signals (up to ~10⁴ fold) compared to conventional probes.
• Achieved high-quality live-cell SRS imaging using PDDA-based probes targeting specific organelles.
• Demonstrated the probes' effectiveness as intrinsic Raman imaging agents in the Raman-silent region.

Conclusions:

• Polydiacetylene-based Raman probes offer ultrastrong intrinsic signals for live-cell imaging in the Raman-silent region.
• PDDA serves as a versatile platform for developing multi-functional Raman probes.
• The flexible functionalization of PDDA holds significant potential for diverse bioimaging applications.