Harnessing Dye-Induced Local Heating in Lipid Membranes: A Path to Near-Infrared Light-Modulated Artificial Synaptic...

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Optical heating with near-infrared (NIR) light and photothermal materials offers localized heating for biospecimens.
• Conventional temperature-sensitive liposomes rely on bulk temperature increases for drug release, potentially causing thermal damage.

Purpose of the Study:

• To investigate photothermally induced changes in lipid bilayer permeability using a phthalocyanine dye (VPc).
• To demonstrate NIR laser-triggered release of encapsulated molecules from liposomes for localized cellular stimulation.

Main Methods:

• Embedding VPc dye within lipid bilayers for photothermal heating.
• Utilizing NIR laser illumination to generate localized heat.
• Preparing VPc-embedded liposomes encapsulating acetylcholine (ACh).
• Assessing Ca²⁺ flux in C2C12 myotubes and *Drosophila* brain following ACh release.

Main Results:

• Photothermal heating of VPc-embedded lipid bilayers increased membrane permeability.
• Localized heating by NIR illumination did not cause significant bulk temperature increase or diffusion.
• NIR laser triggered the release of ACh from VPc-liposomes.
• Induced Ca²⁺ flux in thermally sensitive cells via ACh receptor stimulation.

Conclusions:

• Photothermal heating of lipid bilayers offers a novel mechanism for controlled permeability changes.
• This method allows for precise, localized release of therapeutics and cellular stimulation.
• The technique is suitable for thermally delicate biological systems.