Efficient Triplet-Triplet Annihilation-Based Upconversion for Nanoparticle Phototargeting.

Area of Science:

• Biomaterials Science
• Nanotechnology
• Photochemistry

Background:

• High-efficiency upconverted light is crucial for advanced triggered drug delivery systems.
• Existing phototriggered systems often require high light intensities or specific wavelengths.
• A need exists for efficient, low-power light-activated therapeutic strategies.

Purpose of the Study:

• To develop a general strategy for photoreactions using triplet-triplet annihilation upconversion (TTA-UC) and Förster resonance energy transfer (FRET).
• To create a light-controlled drug delivery system utilizing green light stimulation.
• To enable photocontrolled cell adhesion via peptide reactivation.

Main Methods:

• Designed PLA-PEG micellar nanoparticles encapsulating photosensitizer and annihilator molecules.
• Utilized TTA-UC to generate upconverted light within the nanoparticle core.
• Employed FRET to transfer energy to a photocleavable group (DEACM) for peptide release.

Main Results:

• Achieved efficient TTA-UC and FRET in nanoparticle cores upon green light stimulation.
• Demonstrated photocleavage of DEACM, reactivating bound cell-binding peptides.
• Showcased photocontrolled cell adhesion with low-irradiance green light irradiation.

Conclusions:

• TTA-UC combined with FRET offers an efficient strategy for phototriggered photoreactions.
• This system enables precise control over peptide-mediated cell adhesion using green light.
• The developed nanoparticles present attractive properties for phototriggered drug delivery and biomedical applications.