Near-Infrared-Triggered Photothermal Aggregation of Polymer-Grafted Gold Nanorods in a Simulated Blood Fluid

Abstract

Gold nanorods were decorated with thermoresponsive copolymers of tailored architecture and constructed from N-isopropyl acrylamide and acrylamide. The copolymers were prepared via reversible addition–fragmentation chain transfer polymerization (RAFT) and immobilized on the gold nanorod surface taking advantage of the aurophilicity of its inherently formed trithiocarbonate groups. The topology as well as the average molecular weight of the copolymers was altered using either a monofunctional or 3-arm star RAFT agent. Two-dimensional arrays of the self-assembled core–shell nanostructures were fabricated by drop-casting showing tunable interparticle spacings. In a simulated blood fluid, the lower critical solution temperature of the nanohybrids could be modified over a significant temperature range around body temperature by adjusting the copolymer composition, the architecture, and/or the size of the polymer. The intrinsic photothermal properties of the gold nanorods were utilized to trigger particle aggregation by irradiation at 808 nm in the optical window of human tissues. In effect, a new nanohybrid system with remotely controllable aggregation via an external NIR-light stimulus for nanomedical applications was developed.

NIR/pH Dual-Responsive DOX-Loaded AuNRs@S-β-CD Nanocomposite for Highly Effective Chemo-photothermal Synergistic Therapy against Lung Cancer Cells

“…Among the different shapes of Au nanoparticles used in PTT, gold nanorods (AuNRs) have been widely investigated for cancer therapy due to their controllable size, unique rod-like shape, and tunable surface plasmon resonance (SPR) characteristic to convert near-infrared (NIR) light into local heat, with their facility for surface functionalization for tumor targeting and excellent biocompatibility. − Nevertheless, photothermal therapy for cancer treatment with AuNRs has a number of limitations . Because the intensity of NIR light gradually decreases as it passes through the body tissues to deeper tumors, the nonporous AuNRs give low photothermal conversion efficiency and loading capacities. − Therefore, light-induced heat conversion is inefficient to kill cancer cells in deep tissues.…”

Kinetically Controlled Site-Specific Self-assembly of Hairy Colloids

“…In solution assemblies of plasmonic NPs as an example, coherent coupling 5 within assembled structures can be used, e.g., for creating materials featuring optical magnetism, 6 enhancing catalytic chemical transformations, 7 colorimetric biosensing, 8 surface-enhanced Raman spectroscopy (SERS)-based imaging within live cells, 9 and potentially photothermal tumor treatment. 10 The described rich phenomenology and application potential of polymer-functionalized NP assemblies call for uncovering underlying assembly mechanisms. Two situations can be discriminated: (i) NP assembly when the polymer layer faces poor solvency conditions (by attractive solvophobic polymer−polymer interactions); and (ii) NP assembly under good solvency conditions for the polymer layer.…”

“…Programmable assembly of polymer-functionalized nanoparticle (NP) building blocks constitutes a powerful design paradigm of nanotechnology and is, therefore, a vibrant topic in materials science. , It allows to combine different nanomaterial properties synergistically or to create and tailor coupling effects between the constituent NP building blocks, , which can give rise to novel or highly enhanced properties. In solution assemblies of plasmonic NPs as an example, coherent coupling within assembled structures can be used, e.g., for creating materials featuring optical magnetism, enhancing catalytic chemical transformations, colorimetric biosensing, surface-enhanced Raman spectroscopy (SERS)-based imaging within live cells, and potentially photothermal tumor treatment …”

Fabrication of Polymer-Metal Nanohybrids - Routes Towards Functional Materials

“…The content of the following chapter has already been published by the author of this work and results were adapted with permission of the journal and the authors. [267]…”