Local Enhancement of Lipid Membrane Permeability Induced by Irradiated Gold Nanoparticles

Abstract

Photothermal therapies are based on the optical excitation of plasmonic nanoparticles in the biological environment. The effects of the irradiation on the biological medium depend critically on the heat transfer process at the nanoparticle interface, on the temperature reached by the tissues as well as on the spatial extent of temperature gradients. Unfortunately, both the temperature and its biological effects are difficult to be probed experimentally at the molecular scale. Here, we approach this problem using nonequilibrium molecular dynamics simulations. We focus on photoporation, a photothermal application based on the irradiation of gold nanoparticles by single, short-duration laser pulses. The nanoparticles, stably bound to cell membranes, convert the radiation into heat, inducing transient changes of membrane permeability. We make a quantitative prediction of the temperature gradient around the nanoparticle upon irradiation by typical experimental laser fluences. Water permeability is locally enhanced around the NP, in an annular region that extends only a few nm far from the nanoparticle interface. We correlate the local enhancement of permeability at the NP-lipid interface to the temperature inhomogeneities of the membrane and to the consequent availability of free volume pockets within the membrane core.

Bimetallic Nanoparticles: Enhanced Magnetic and Optical Properties for Emerging Biological Applications

“…As previously mentioned, bimetallic nanomaterials, especially gold-based bimetallic nanoparticles, can be designed for activation at visible and NIR wavelengths, making them suitable for use in photothermal cancer therapy. For example, bimetallic AgAu nanocages have been evaluated as potential materials for photothermal therapy [69,185]. The surface plasmon resonance of these types of nanocages can be tuned to the NIR region (800 to 2500 nm), making them compatible with the wavelength of laser irradiation used in many photothermal therapies [38].…”

The Role of Temperature and Lipid Charge on Intake/Uptake of Cationic Gold Nanoparticles into Lipid Bilayers

“…It has also been reported that AuNPs with amphiphilic side chains can penetrate in defect‐free low‐curvature membranes due to the hydrophobic interplay between the AuNP side chains and lipids . The transmembrane state is stabilized by “snorkeling” or “anchoring” where the charged AuNP terminal groups reach out of the bilayer interior …”

Anionic nanoparticle-lipid membrane interactions: the protonation of anionic ligands at the membrane surface reduces membrane disruption

“…S1 of the ESI. These NP core and surface composition have become a reference for the study of NP-membrane interactions 14,17,[20][21][22][23][24][25] , and many experimental and computational results indicate the existence of a stable NP-membrane interaction.…”