Heat Transfer in Gold Interfaces Capped with Thiolated Polyethylene Glycol: A Molecular Dynamics Study

Abstract

Reverse nonequilibrium molecular dynamics simulations were used to study heat transport in solvated gold interfaces which have been functionalized with a low-molecular weight thiolated polyethylene glycol (PEG). The gold interfaces studied included (111), (110), and (100) facets as well as spherical nanoparticles with radii of 10 and 20 Å. The embedded atom model (EAM) and the polarizable densityreadjusted embedded atom model (DR-EAM) were implemented to determine the effect of metal polarizability on heat transport properties. We find that the interfacial thermal conductance values for thiolated PEG-capped interfaces are higher than those for pristine gold interfaces. Hydrogen bonding between the thiolated PEG and solvent differs between planar facets and the nanospheres, suggesting one mechanism for enhanced transfer of energy, while the covalent gold sulfur bond appears to create the largest barrier to thermal conduction. Through analysis of vibrational power spectra, we find an enhanced population at low-frequency heat-carrying modes for the nanospheres, which may also explain the higher mean interfacial thermal conductance (G) value.

Strategies Employed to Design Biocompatible Metal Nanoparticles for Medical Science and Biotechnology Applications

“…121 As an example, a SAM comprising thiolated PEG is commonly utilized to establish a biocompatible surface, effectively mitigating nonspecific adsorption of undesired proteins and improving biosensor stability minimizing background interference. 123 Additionally, the linker molecule 11mercaptoundecanoic acid (MUA) serves as a self-assembled capping agent, creating spatial separation between the sensor surface and immobilized biomolecules. This not only prevents steric hindrance but also enhances the accessibility of target molecules to the sensor surface, thereby improving the binding efficiency.…”