Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials

Area of Science:

• Chemistry
• Biochemistry
• Materials Science

Background:

• Photoactivatable protecting groups (PPGs) enable spatiotemporal control over chemical release.
• Recent advancements include PPGs activated by visible and near-infrared (NIR) light, enhancing accessibility and applicability.
• These long-wavelength-absorbing PPGs are crucial for non-invasive photochemical control.

Purpose of the Study:

• To comprehensively review organic and transition metal-containing photoactivatable compounds absorbing in the visible and NIR range.
• To discuss various release mechanisms including direct cleavage, photosensitization, photodynamic effects, and photothermal effects.
• To cover applications in photoactivatable polymers, micelles, vesicles, photoswitches, and the emerging field of photopharmacology.

Main Methods:

• Review of literature on photoactivatable compounds and their applications.
• Categorization of PPGs based on absorption wavelength (visible and NIR).
• Discussion of different release triggers and mechanisms (photochemical, photosensitized, photodynamic, photothermal).

Main Results:

• Detailed overview of organic and transition metal-based PPGs absorbing visible and NIR light.
• Exploration of PPGs for releasing leaving groups and gasotransmitters (CO, NO, H2S).
• Coverage of advanced release strategies using nanoparticles and photodynamic/photothermal effects.

Conclusions:

• Visible and NIR-activated PPGs represent a significant advancement in photochemical control.
• These PPGs offer versatile platforms for applications ranging from chemical biology to materials science.
• The review highlights the expanding scope and accessibility of photoactivatable technologies, including photopharmacology.