Supramolecular nanoreactors for intracellular singlet-oxygen sensitization

Area of Science:

• Supramolecular chemistry
• Polymer science
• Nanotechnology
• Photochemistry

Background:

• Amphiphilic polymers self-assemble into nanoparticles in aqueous environments.
• These nanoparticles can encapsulate hydrophobic molecules like chromophores.
• Controlled intracellular delivery of therapeutic agents is crucial for targeted treatments.

Purpose of the Study:

• To develop self-assembling nanoparticles for co-delivery of anthracene and BODIPY chromophores into cancer cells.
• To investigate mechanisms of intracellular chromophore transport and energy transfer.
• To explore the potential of these systems for photodynamic therapy (PDT).

Main Methods:

• Synthesis of amphiphilic poly(methacrylate) backbone with decyl and oligo(ethylene glycol) chains.
• Co-encapsulation of hydrophobic anthracene and BODIPY chromophores into self-assembled nanoparticles.
• Cell culture studies (HeLa cells) to assess nanoparticle uptake and intracellular cargo delivery.
• Spectroscopic analysis to monitor energy transfer and singlet oxygen generation.

Main Results:

• Nanoparticles successfully encapsulated and transported anthracene and BODIPY chromophores into HeLa cells via endocytosis.
• Two delivery mechanisms (simultaneous vs. sequential) were demonstrated, leading to intracellular co-localization.
• Efficient Förster Resonance Energy Transfer (FRET) from anthracene to BODIPY was observed intracellularly.
• Iodinated BODIPY facilitated intersystem crossing and singlet oxygen generation upon excitation, leading to cell death.
• Near-infrared two-photon excitation enabled deep tissue penetration for in vivo PDT applications.

Conclusions:

• Self-assembling amphiphilic polymer nanoparticles provide a versatile platform for intracellular co-delivery of multiple chromophores.
• Controlled intracellular energy transfer dynamics can be achieved, leading to efficient singlet oxygen production.
• These supramolecular systems hold significant promise for developing advanced photodynamic therapy strategies.