Gold Nanostars Embedded in PDMS Films: A Photothermal Material for Antibacterial Applications

Abstract

Bacteria infections and related biofilms growth on surfaces of medical devices are a serious threat to human health. Controlled hyperthermia caused by photothermal effects can be used to kill bacteria and counteract biofilms formation. Embedding of plasmonic nano-objects like gold nanostars (GNS), able to give an intense photothermal effect when irradiated in the NIR, can be a smart way to functionalize a transparent and biocompatible material like polydimethylsiloxane (PDMS). This process enables bacteria destruction on surfaces of PDMS-made medical surfaces, an action which, in principle, can also be exploited in subcutaneous devices. We prepared stable and reproducible thin PDMS films containing controllable quantities of GNS, enabling a temperature increase that can reach more than 40 degrees. The hyperthermia exerted by this hybrid material generates an effective thermal microbicidal effect, killing bacteria with a near infrared (NIR) laser source with irradiance values that are safe for skin.

Flexible, stretchable, and single-molecule-sensitive SERS-active sensor for wearable biosensing applications

“…30,31 Gold nanoparticles (Au-NP) on PDMS substrate is robust and stable while offering reliable flexibility and the storage time of the metasurface can extend from more than 15 days up to two months if kept at 4 °C, preferably in an N 2 ambient. 32–34 Furthermore, surface modifications on PDMS can enhance the adhesion of active materials such as gold (Au) that can lead to improved stability of the proposed metasurface. 31,35…”

Impact of Ligand Exchange on Gold Nanostars’ Reshaping, Stabilization, Photothermal Efficiency, and Cell Viability

“…16 Multiple studies have focused on developing synthetic processes that achieve a high degree of morphology control of AuNSs and thus enable to tune their properties. 17,18 Prominently, AuNSs have been used as high-performing substrate materials for biosensing and biodetection, 19 photothermal therapy, 20 drug delivery, 21 and imaging. 22 Nevertheless, due to the exclusive focus on their potential applications, there is limited literature exploring the effects of ligand interactions on poor stability conditions of AuNSs.…”

“…The LSPR of these nanoparticles depends on the arms’ lengths and the aspect ratio, which allows for tuning their optical properties in ranges of the first and second biological window, where the body tissues show the highest optical transmissivity. , The unprecedented local enhancement of the near electric field and light concentration are due to the presence of the sharp tips or edges, which constitute the so-called hotspots, and are the reason for better enhancement factors in surface-enhanced Raman scattering (SERS) , and surface-enhanced fluorescence (SEF), , as well as high sensitivity of the plasmonic band to the surrounding medium . Multiple studies have focused on developing synthetic processes that achieve a high degree of morphology control of AuNSs and thus enable to tune their properties. , Prominently, AuNSs have been used as high-performing substrate materials for biosensing and biodetection, photothermal therapy, drug delivery, and imaging . Nevertheless, due to the exclusive focus on their potential applications, there is limited literature exploring the effects of ligand interactions on poor stability conditions of AuNSs .…”

Rapidly responsive liquid metal/polyimide photothermal actuators designed based on the bilayer structure difference in coefficient of thermal expansion

“…In contrast, a liquid metal (LM), as an emerging flexible material, combines the fluidity of liquid 13 with the electrical conductivity 14 and thermal conductivity 15 of metal. What's more, similar to gold nanocrystals 16 and silver nanocrystals, 17 LM particles have photothermal effects in the nearinfrared (NIR) laser. 18,19 Meanwhile, due to the flexibility of LM, it can better bind to the polymer matrix as a filler, adapts to various deformations and doesn't decrease the response speed of the photoactuator.…”