Abstract
Nanoheaters are promising tools for localized photothermal therapy (PTT) of malignant cells. The anisotropic AuNPs present tunable surface plasmon resonances (SPR) with ideal NIR optical response to be applied as theranostic agents. To this purpose, nanoparticles with branches are suitable because of the electromagnetic field concentrated at their vertices. We standardized a protocol to synthesize multibranched gold nanoparticles (MB-AuNPs) by the seed-growth method and found a size-seed dependence tunability on the hierarchy of branching. Once the optical response is evaluated, we tested the temporal stability as nanoheaters of the MB-AuNPs immersed in skin-equivalent phantoms by dynamic infrared thermography (DIRT). The most suited sample presents a concentration of 5.2×108 MB-AuNPs/mL showing good thermal stability with ΔT = 4.5°C, during 3 cycles of 10 min at 785 nm laser irradiation with power of 0.15 W. According to these results, the MB-AuNPs are suitable nanoheaters to be tested for PTT in more complex models.
Highlights
The last twenty years’ research reports on nanostructured materials clearly indicate their potential to develop new technologies for different specialized areas
In order to prepare monodisperse MB-AuNPs, presynthesized gold single-crystalline and multitwinned nanoparticles are used as seeds for the growth of peaks [28, 29], which grow along preferential crystallographic directions of the metallic core [35]
Even if an excess of hydroxylamine may result in a better definition of tips, it can cause the agglomeration of MB-AuNPs, due to the resulting high ionic force of the solution, that could not be used for clinical applications, and the same argument is valid for higher concentration of HEPES (75 mM)
Summary
The last twenty years’ research reports on nanostructured materials clearly indicate their potential to develop new technologies for different specialized areas. Gold plays a particular and special role in this area of size and shape controlled synthesis, and because of their properties, those NPs are studied for technological applications in fields such as renewable energies, catalysis, medicine, and photonics. Because of the optical and low-reactive properties of gold nanoparticles (AuNPs), they have been considered for medical applications as theranostic agents, which means that they can be simultaneously used for drug delivery [1], medical imaging [2,3,4,5], localized photothermal therapy (PTT) [6], and biological sensing [7, 8]. For some specific theranostic applications AuNPs are designed with anisotropic shapes, characteristic that tunes their surface plasmon resonance (SPR) from the visible to the near (NIR) and middle infrared (Mid-IR) regions of the spectra, presenting local concentration of electromagnetic fields on the vertices [9]. The fact that NIR absorbance of MB-AuNPs fits the so-called therapeutic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
