Gold Nanodisks Plasmonic Array for Hydrogen Sensing at Low Temperature

We present a novel plasmonic hydrogen sensor consisting of an array of gold nanodisks produced by lithography. The size, height, and spacing of the disks were optimized using finite element simulation to generate a sharp localized surface plasmon resonance peak in the near-infrared wavelength region. The reported results show the possibility of developing an optical gas sensors-based bare Au nanostructures operating at a low temperature

Versatile magnetic configuration for the control and manipulation of superparamagnetic nanoparticles

Abstract The control and manipulation of superparamagnetic nanoparticles (SP-MNP) is a significant challenge and has become increasingly important in various fields, especially in biomedical research. Yet, most of applications rely on relatively large nanoparticles, 50 nm or higher, mainly due to the fact that the magnetic control of smaller MNPs is often hampered by the thermally induced Brownian motion. Here we present a magnetic device able to manipulate remotely in microfluidic environment SP-MNPs smaller than 10 nm. The device is based on a specifically tailored configuration of movable permanent magnets. The experiments performed in 500 µm capillary have shown the ability to concentrate the SP-MNPs into regions characterized by different shapes and sizes ranging from 100 to 200 µm. The results are explained by straightforward calculations and comparison between magnetic and thermal energies. We provide then a comprehensive description of the magnetic field intensity and its spatial distribution for the confinement and motion of magnetic nanoparticles for a wide range of sizes. We believe this description could be used to establish accurate and quantitative magnetic protocols not only for biomedical applications, but also for environment, food, security, and other areas

Spontaneous formation of magnetic-plasmonic liposomes with tunable optical and magnetic properties

Magnetoplasmonic NPs have shown remarkable potential in hyperthermia, Magnetic Resonance Imaging (MRI), and Surface Enhanced Raman Scattering (SERS) imaging and diagnostics. However, despite their potential, effective clinical translation remains extremely limited due to a lack of fundamental knowledge about the biological response to these materials, and ongoing efforts seek to bridge the gap between nanomaterial production and effective application. To overcome these hurdles, the combination of inorganic NPs with lipid membranes has emerged as a promising strategy for the biocompatibilization of nanomaterials, preserving the inherent properties of each component and exhibiting novel synergistic functionalities. In this study, we synthesize magnetic-plasmonic-liposome adducts via spontaneous self-assembly. The interaction between magnetic-plasmonic NPs and liposomes was addressed from a physicochemical point of view as a function of liposome composition and concentration. By combining Cryogenic Microscopy, UV-visible spectroscopy and Dynamic Light Scattering we demonstrated that the rigidity of the lipid membrane affects the aggregation of the NPs and the colloidal stability of the NPs-vesicle hybrids. The magnetic responsivity of the hybrids is enhanced as a consequence of the colocalization and crowding of NPs on the lipid membranes and can be finely modulated by varying the number of particles per vesicle. Overall, these results pave the way for the development of multifunctional materials with controlled magnetic-plasmonic properties for a variety of technological applications

Magnetic separation and concentration of Aβ 1–42 molecules dispersed at the threshold concentration for Alzheimer’s disease diagnosis in clinically-relevant volumes of sample

Abstract Background Alzheimer’s disease (AD) is the leading cause of dementia and loss of autonomy in the elderly, implying a progressive cognitive decline and limitation of social activities. The progressive aging of the population is expected to exacerbate this problem in the next decades. Therefore, there is an urgent need to develop quantitative diagnostic methodologies to assess the onset the disease and its progression especially in the initial phases. Results Here we describe a novel technology to extract one of the most important molecular biomarkers of AD (Aβ1−42) from a clinically-relevant volume − 100 µl – therein dispersed in a range of concentrations critical for AD early diagnosis. We demonstrate that it is possible to immunocapture Aβ1−42 on 20 nm wide magnetic nanoparticles functionalized with hyperbranced KVLFF aptamers. Then, it is possible to transport them through microfluidic environments to a detection system where virtually all (~ 90%) the Aβ1−42 molecules are concentrated in a dense plug of ca.50 nl. The technology is based on magnetic actuation by permanent magnets, specifically designed to generate high gradient magnetic fields. These fields, applied through submillimeter-wide channels, can concentrate, and confine magnetic nanoparticles (MNPs) into a droplet with an optimized shape that maximizes the probability of capturing highly diluted molecular biomarkers. These advancements are expected to provide efficient protocols for the concentration and manipulation of molecular biomarkers from clinical samples, enhancing the accuracy and the sensitivity of diagnostic technologies. Conclusions This easy to automate technology allows an efficient separation of AD molecular biomarkers from volumes of biological solutions complying with the current clinical protocols and, ultimately, leads to accurate measurements of biomarkers. The technology paves a new way for a quantitative AD diagnosis at the earliest stage and it is also adaptable for the biomarker analysis of other pathologies

Incorporation of Eu-Tb codoped nanophosphors in silica-based coatings assisted by atmospheric pressure plasma jet technology

Different deposition methods of nanocomposite silica films with embedded Y2O3:Eu3+, Tb3+ by atmospheric pressure plasma jet (APPJ) technology are presented.We found that a two-step strategy consisting in the APPJ deposition of a silica film on previously deposited nanophosphors is a very efficientmethod to obtain nanocomposite coatings with excellent adhesion to the substrate.Moreover the APPJ deposited silica film ensures protection of the luminescent nanoparticles and preserves the photoluminescence emission properties of the nanophosphors. Optically active coatings can be therefore deposited by using this technology

Synthesis and Characterization of a Biocompatible Nanoplatform Based on Silica-Embedded SPIONs Functionalized with Polydopamine

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained increasing interest in nanomedicine, but most of those that have entered the clinical trials have been withdrawn due to toxicity concerns. Therefore, there is an urgent need to design low-risk and biocompatible SPION formulations. In this work, we present an original safe-by-design nanoplatform made of silica nanoparticles loaded with SPIONs and decorated with polydopamine (SPIONs@SiO2-PDA) and the study of its biocompatibility performance by an ad hoc thorough in vitro to in vivo nanotoxicological methodology. The results indicate that the SPIONs@SiO2-PDA have excellent colloidal stability in serum-supplemented culture media, even after long-term (24 h) exposure, showing no cytotoxic or genotoxic effects in vitro and ex vivo. Physiological responses, evaluated in vivo using Caenorhabditis elegans as the animal model, showed no impact on fertility and embryonic viability, induction of an oxidative stress response, and a mild impact on animal locomotion. These tests indicate that the synergistic combination of the silica matrix and PDA coating we developed effectively protects the SPIONs, providing enhanced colloidal stability and excellent biocompatibility

Synthesis and Characterization of a Biocompatible Nanoplatform Based on Silica-Embedded SPIONs Functionalized with Polydopamine

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained increasing interest in nanomedicine, but most of those that have entered the clinical trials have been withdrawn due to toxicity concerns. Therefore, there is an urgent need to design low-risk and biocompatible SPION formulations. In this work, we present an original safe-by-design nanoplatform made of silica nanoparticles loaded with SPIONs and decorated with polydopamine (SPIONs@SiO2-PDA) and the study of its biocompatibility performance by an ad hoc thorough in vitro to in vivo nanotoxicological methodology. The results indicate that the SPIONs@SiO2-PDA have excellent colloidal stability in serum-supplemented culture media, even after long-term (24 h) exposure, showing no cytotoxic or genotoxic effects in vitro and ex vivo. Physiological responses, evaluated in vivo using Caenorhabditis elegans as the animal model, showed no impact on fertility and embryonic viability, induction of an oxidative stress response, and a mild impact on animal locomotion. These tests indicate that the synergistic combination of the silica matrix and PDA coating we developed effectively protects the SPIONs, providing enhanced colloidal stability and excellent biocompatibility