Unprecedented Photoinduced-Electron-Transfer Probe with a Turn-ON Chemiluminescence Mode-of-Action

Area of Science:

• Chemical Biology
• Biotechnology
• Molecular Imaging

Background:

• Photoinduced electron transfer (PeT) probes enhance fluorescence upon target binding.
• Existing PeT probes primarily operate in fluorescence mode.
• There is a lack of PeT probes utilizing chemiluminescence.

Purpose of the Study:

• To develop and characterize the first PeT-based turn-on probe operating in a chemiluminescent mode.
• To demonstrate the probe's efficacy in detecting and imaging model proteins.
• To compare the probe's performance against existing fluorescent analogs.

Main Methods:

• Design and synthesis of a novel chemiluminescent probe incorporating a phenoxy-1,2-dioxetane and an azide unit.
• Utilizing click chemistry (cycloaddition) between the azide and strained cycloalkyne for probe activation.
• Conjugation of the probe to model proteins (Myc-DBCO, Max-DBCO) via NHS or maleimide chemistry.
• Evaluation of probe performance, including signal-to-noise ratio and imaging capabilities.

Main Results:

• Successful synthesis of a novel PeT-based chemiluminescent probe.
• Demonstrated a high signal-to-noise ratio (over 5000-fold) due to slow chemiexcitation.
• Effective detection and imaging of model proteins labeled with strained cycloalkyne.
• The chemiluminescent probe significantly outperformed a commercial fluorescent analog.

Conclusions:

• This work presents the first PeT-based chemiluminescent turn-on probe.
• The developed probe offers enhanced detection and imaging capabilities with a high signal-to-noise ratio.
• This study paves the way for developing new chemiluminescent probes based on various PeT-quenching mechanisms.