tethered-bilayer-lipid-membranes-to-monitor-heat-transfer-between

Tethered Bilayer Lipid Membranes to Monitor Heat Transfer between Gold Nanoparticles and Lipid Membranes

Here we report a protocol to investigate the heat transfer between irradiated gold nanoparticles (GNPs) and bilayer lipid membranes by electrochemistry ...

The University of New South Wales

Gold nanoparticle (GNP) aggregation has a strong influence on the plasmonic resonance and hence the effectiveness in various photothermal applications. In relation to this, a comprehensive numerical model is developed to simulate and characterize the GNP aggregation process at various particle volume fractions and base fluid pH levels. Computational fluid dynamics techniques are utilized to model the base fluid, whereas discrete phase modeling is adopted in determining the nanoparticle trajectories. Two-way coupling is implemented to handle the particle-fluid interactions. Discrete dipole approximation approach is utilized to further examine the absorption and scattering efficiency of various GNP aggregate structures. At lower particle volume fraction, short chain-like structures are formed in the particle aggregation process, with a more complex interconnected "particle network" structure formed at higher particle volume fractions. With the three base fluid pH levels investigated, GNP aggregates are more compact with larger fractal dimensions and higher mean coordination numbers at pH = 3.5, whereas a more "loose" structure formed at pH = 6.7 and 9.4 because of larger electrostatic repulsive forces as a result of changes in the zeta potential and Debye length of the GNPs. Among the typical GNP aggregate structures characterized in this paper, the chain-like tetramer demonstrates the highest absorption efficiency of 1.83 at 700 nm wavelength-comparable to the plasmonic resonance of a nanorod-which lies in the optical window of biological tissue. Predictions of GNP optical properties are found to be in good agreement with the published experimental data.

Study of Morphology and Optical Properties of Gold Nanoparticle Aggregates under Different pH Conditions.

Plasmon resonance frequency irradiated gold nanoparticles (GNPs) have gained interest as a laser-targeted treatment for infections, tumors and for the controlled release of drugs in situ. Questions still remain, however, as to the efficiency of heat delivery within biological tissues and how this can be reliably determined. Here, we demonstrate how a nanomaterial-electrode interface that mimics cell membranes can detect the localized heat transfer characteristics arising from plasmon resonance frequency-matched laser excitation of GNPs. We demonstrate that the lipid bilayer membrane can be affected by conjugated GNP induced hyperthermia when irradiated with a laser power output as low as 135 nW/μm. This is four orders of magnitude lower power than previously reported. By restricting the lateral movement of the lipids in the bilayer membrane, it was shown that the change in membrane conductance as a result of the heat transfer was due to the creation of transient lipidic toroidal pores within the membrane. We further demonstrate that the heat transfer from the GNPs alters diffusion rates of monomers of the gramicidin-A peptide within the lipid leaflets. This work highlights how targeted low laser power GNP hyperthermia treatments, in vivo, could play a dual role of interfering with both cell membrane morphology and dynamics, along with membrane protein function.

Xi Gu

School of Mechanical and Manufacturing Engineering

The University of New South Wales

Tethered Bilayer Lipid Membranes to Monitor Heat Transfer between Gold Nanoparticles and Lipid Membranes

Xi Gu

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}School of Mechanical and Manufacturing Engineering

The University of New South Wales

Tethered Bilayer Lipid Membranes to Monitor Heat Transfer between Gold Nanoparticles and Lipid Membranes

School of Mechanical and Manufacturing Engineering