Self-sensing porphysomes for fluorescence-guided photothermal therapy

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Photothermal Therapy

Background:

• Porphysomes are nanovesicles with photothermal properties for therapy.
• Porphysome structure disruption enables fluorescence-guided ablation but is hard to track.
• Existing methods cannot easily monitor porphysome structural changes over time.

Purpose of the Study:

• To design a novel self-sensing porphysome (FRETysome) for real-time monitoring of structural state.
• To utilize Förster resonance energy transfer (FRET) for broadcasting vesicle integrity.
• To enable fluorescence-guided photothermal ablation with improved tracking.

Main Methods:

• Incorporated a near-infrared emitting fluorophore and a bacteriopheophorbide-lipid acceptor into porphysome bilayers.
• Utilized FRET to measure energy transfer efficiency based on vesicle structure.
• Employed hyperspectral imaging for in vivo visualization and structural fate determination.

Main Results:

• FRETysomes demonstrated tunable FRET efficiency (14.6-72.7%) with a 100 nm absorption-fluorescence band separation.
• Photothermal heating and serum stability of FRETysomes were comparable to undoped porphysomes.
• In vivo hyperspectral imaging allowed clear visualization of FRET signals and determination of nanovesicle structural fate, showing intact accumulation at 24 and 48 hours postinjection.

Conclusions:

• FRETysomes provide a self-sensing capability to monitor nanovesicle structural changes.
• This technology enables real-time tracking of porphysome accumulation and integrity in vivo.
• FRETysomes are a critical imaging tool for optimizing porphysome-based fluorescence-guided photothermal treatments.