Multifunctional FFP2 Face Mask for White Light Disinfection and Pathogens Detection using Hybrid Nanostructures and Optical Metasurfaces.

A new generation of an FFP2 (Filtering Face Piece of type 2) smart face mask is achieved by integrating broadband hybrid nanomaterials and a self-assembled optical metasurface. The multifunctional FFP2 face mask shows simultaneously white light-assisted on-demand disinfection properties and versatile biosensing capabilities. These properties are achieved by a powerful combination of white light thermoplasmonic responsive hybrid nanomaterials, which provide excellent photo-thermal disinfection properties, and optical metasurface-based colorimetric biosensors, with a very low limit of pathogens detection. The realized system is studied in optical, morphological, spectroscopic, and cell viability assay experiments and environmental monitoring of harmful pathogens, thus highlighting the extraordinary properties in reusability and pathogens detection of the innovative face mask.

Biomimetic Keratin-Coated Gold Nanoparticles for Photo-Thermal Therapy in a 3D Bioprinted Glioblastoma Tumor Model.

Before entering human clinical studies to evaluate their safety and effectiveness, new drugs and novel medical treatments are subject to extensive animal testing that are expensive and time-consuming. By contrast, advanced technologies enable the development of animal-free models that allow the efficacy of innovative therapies to be studied without sacrificing animals, while providing helpful information and details. We report on the powerful combination of 3D bioprinting (3DB) and photo-thermal therapy (PTT) applications. To this end, we realize a 3DB construct consisting of glioblastoma U87-MG cells in a 3D geometry, incorporating biomimetic keratin-coated gold nanoparticles (Ker-AuNPs) as a photo-thermal agent. The resulting plasmonic 3DB structures exhibit a homogeneous cell distribution throughout the entire volume while promoting the localization of Ker-AuNPs within the cells. A 3D immunofluorescence assay and transmission electron microscopy (TEM) confirm the uniform distribution of fluorescent-labeled Ker-AuNPs in the volume and their capability to enter the cells. Laser-assisted (λ = 532 nm) PTT experiments demonstrate the extraordinary ability of Ker-AuNPs to generate heating, producing the highest temperature rise of about 16 °C in less than 2 min.

Recent advances towards point-of-care devices for fungal detection: Emphasizing the role of plasmonic nanomaterials in current and future technologies.

Fungal infections are a significant global health problem, particularly affecting individuals with weakened immune systems. Moreover, as uncontrolled antibiotic and immunosuppressant use increases continuously, fungal infections have seen a dramatic increase, with some strains developing antibiotic resistance. Traditional approaches to identifying fungal strains often rely on morphological characteristics, thus owning limitations, such as struggles in identifying several strains or distinguishing between fungal strains with similar morphologies. This review explores the multifaceted impact of fungi infections on individuals, healthcare providers, and society, highlighting the often-underestimated economic burden and healthcare implications of these infections. In light of the serious constraints of traditional fungal identification methods, this review discusses the potential of plasmonic nanoparticle-based biosensors for fungal infection identification. These biosensors can enable rapid and precise fungal pathogen detection by exploiting several readout approaches, including various spectroscopic techniques, colorimetric and electrochemical assays, as well as lateral-flow immunoassay methods. Moreover, we report the remarkable impact of plasmonic Lab on a Chip technology and microfluidic devices, as they recently emerged as a class of advanced biosensors. Finally, we provide an overview of smartphone-based Point-of-Care devices and the associated technologies developed for detecting and identifying fungal pathogens.

Lysozyme-sensitive plasmonic hydrogel nanocomposite for colorimetric dry-eye inflammation biosensing.

Detection of lysozyme levels in ocular fluids is considered crucial for diagnosing and monitoring various health and eye conditions, including dry-eye syndrome. Hydrogel-based nanocomposites have been demonstrated to be one of the most promising platforms for fast and accurate sensing of different biomolecules. In this work, hydrogel, electrospun nanofibers, and plasmonic nanoparticles are combined to fabricate a sensitive and easy-to-use biosensor for lysozyme. Poly(L-lactide-co-caprolactone) (PLCL) nanofibers were covered with silver nanoplates (AgNPls), providing a stable plasmonic platform, where a poly(N-isopropylacrylamide)-based (PNIPAAm) hydrogel layer allows mobility and good integration of the biomolecules. By integrating these components, the platform can also exhibit a colorimetric response to the concentration of lysozyme, allowing for easy and non-invasive monitoring. Quantitative biosensing operates on the principle of localized surface plasmon resonance (LSPR) induced by plasmonic nanoparticles. Chemical, structural, thermal, and optical characterizations were performed on each platform layer, and the platform's ability to detect lysozyme at concentrations relevant to those found in tears of patients with dry-eye syndrome and other related diseases was investigated by colorimetry and UV-Vis spectroscopy. This biosensor's sensitivity and rapid response time, alongside the easy detection by the naked eye, make it a promising tool for early diagnosis and treatment monitoring of eye diseases.

18F-fluorodeoxyglucose (18F-FDG) Functionalized Gold Nanoparticles (GNPs) for Plasmonic Photothermal Ablation of Cancer: A Review.

The meeting and merging between innovative nanotechnological systems, such as nanoparticles, and the persistent need to outperform diagnostic-therapeutic approaches to fighting cancer are revolutionizing the medical research scenario, leading us into the world of nanomedicine. Photothermal therapy (PTT) is a non-invasive thermo-ablative treatment in which cellular hyperthermia is generated through the interaction of near-infrared light with light-to-heat converter entities, such as gold nanoparticles (GNPs). GNPs have great potential to improve recovery time, cure complexity, and time spent on the treatment of specific types of cancer. The development of gold nanostructures for photothermal efficacy and target selectivity ensures effective and deep tissue-penetrating PTT with fewer worries about adverse effects from nonspecific distributions. Regardless of the thriving research recorded in the last decade regarding the multiple biomedical applications of nanoparticles and, in particular, their conjugation with drugs, few works have been completed regarding the possibility of combining GNPs with the cancer-targeted pharmaceutical fluorodeoxyglucose (FDG). This review aims to provide an actual scenario on the application of functionalized GNP-mediated PTT for cancer ablation purposes, regarding the opportunity given by the 18F-fluorodeoxyglucose (18F-FDG) functionalization.

Thermoplasmonic Controlled Optical Absorber Based on a Liquid Crystal Metasurface.

Metasurfaces can be realized by organizing subwavelength elements (e.g., plasmonic nanoparticles) on a reflective surface covered with a dielectric layer. Such an array of resonators, acting collectively, can completely absorb the resulting resonant wavelength. Unfortunately, despite the excellent optical properties of metasurfaces, they lack the tunability to perform as adaptive optical components. To boost the utilization of metasurfaces and realize a new generation of dynamically controlled optical components, we report our recent finding based on the powerful combination of an innovative metasurface-optical absorber and nematic liquid crystals (NLCs). The metasurface consists of self-assembled silver nanocubes (AgNCs) immobilized on a 50 nm thick gold layer by using a polyelectrolyte multilayer as a dielectric spacer. The resulting optical absorbers show a well-defined reflection band centered in the near-infrared of the electromagnetic spectrum (750-770 nm), a very high absorption efficiency (∼60%) at the resonant wavelength, and an elevated photothermal efficiency estimated from the time constant value (34 s). Such a metasurface-based optical absorber, combined with an NLC layer, planarly aligned via a photoaligned top cover glass substrate, shows homogeneous NLC alignment and an absorption band photothermally tunable over approximately 46 nm. Detailed thermographic studies and spectroscopic investigations highlight the extraordinary capability of the active metasurface to be used as a light-controllable optical absorber.

Au nanoparticles decorated nanographene oxide-based platform: Synthesis, functionalization and assessment of photothermal activity.

A novel hybrid nanocomposite formed of carboxylated Nano Graphene Oxide (c-NGO), highly densely decorated by monodisperse citrate-coated Au nanoparticles (c-NGO/Au NPs), is synthesized and thoroughly characterized for photothermal applications. A systematic investigation of the role played by the synthetic parameters on the Au NPs decoration of the c-NGO platform is performed, comprehensively studying spectroscopic and morphological characteristics of the achieved nanostructures, thus elucidating their still not univocally explained synthesis mechanism. Remarkably, the Au NPs coating density of the c-NGO sheets is much higher than state-of-the-art systems with analogous composition prepared with different approaches, along with a higher NPs size dispersion. A novel theoretical approach for estimating the average number of NPs per sheet, combining DLS and TEM results, is developed. The assessment of the c-NGO/Au NPs photothermal activity is performed under continuous wave (CW) laser irradiation, at 532 nm and 800 nm, before and after functionalization with PEG-SH. c-NGO/Au NPs composite behaves as efficient photothermal agent, with a light into heat conversion ability higher than that of the single components. The c-NGO/Au NPs compatibility for photothermal therapy is assessed by in vitro cell viability tests, which show no significant effects of c-NGO/Au NPs, as neat and PEGylated, on cell metabolic activity under the investigated conditions. These results demonstrate the great potential held by the prepared hybrid nanocomposite for photothermal conversion technologies, indicating it as particularly promising platform for photothermal ablation of cancer cells.

White light thermoplasmonic activated gold nanorod arrays enable the photo-thermal disinfection of medical tools from bacterial contamination.

The outspread of bacterial pathogens causing severe infections and spreading rapidly, especially among hospitalized patients, is worrying and represents a global public health issue. Current disinfection techniques are becoming insufficient to counteract the spread of these pathogens because they carry multiple antibiotic-resistance genes. For this reason, a constant need exists for new technological solutions that rely on physical methods rather than chemicals. Nanotechnology support provides novel and unexplored opportunities to boost groundbreaking, next-gen solutions. With the help of plasmonic-assisted nanomaterials, we present and discuss our findings in innovative bacterial disinfection techniques. Gold nanorods (AuNRs) immobilized on rigid substrates are utilized as efficient white light-to-heat transducers (thermoplasmonic effect) for photo-thermal (PT) disinfection. The resulting AuNRs array shows a high sensitivity change in refractive index and an extraordinary capability in converting white light to heat, producing a temperature change greater than 50 °C in a few minute interval illumination time. Results were validated using a theoretical approach based on a diffusive heat transfer model. Experiments performed with a strain of Escherichia coli as a model microorganism confirm the excellent capability of the AuNRs array to reduce the bacteria viability upon white light illumination. Conversely, the E. coli cells remain viable without white light illumination, which also confirms the lack of intrinsic toxicity of the AuNRs array. The PT transduction capability of the AuNRs array is utilized to produce white light heating of medical tools used during surgical treatments, generating a temperature increase that can be controlled and is suitable for disinfection. Our findings are pioneering a new opportunity for healthcare facilities since the reported methodology allows non-hazardous disinfection of medical devices by simply employing a conventional white light lamp.

Nanotechnology Transition Roadmap toward Multifunctional Stimuli-Responsive Face Masks.

In recent times, the use of personal protective equipment, such as face masks or respirators, is becoming more and more critically important because of common pollution; furthermore, face masks have become a necessary element in the global fight against the COVID-19 pandemic. For this reason, the main mission of scientists has become the development of face masks with exceptional properties that will enhance their performance. The versatility of electrospun polymer nanofibers has determined their suitability as a material for constructing "smart" filter media. This paper provides an overview of the research carried out on nanofibrous filters obtained by electrospinning. The progressive development of the next generation of face masks whose unique properties can be activated in response to a specific external stimulus is highlighted. Thanks to additional components incorporated into the fiber structure, filters can, for example, acquire antibacterial or antiviral properties, self-sterilize the structure, and store the energy generated by users. Despite the discovery of several fascinating possibilities, some of them remain unexplored. Stimuli-responsive filters have the potential to become products of large-scale availability and great importance to society as a whole.

NIR-Absorbing Mesoporous Silica-Coated Copper Sulphide Nanostructures for Light-to-Thermal Energy Conversion.

Plasmonic nanostructures, featuring near infrared (NIR)-absorption, are rising as efficient nanosystems for in vitro photothermal (PT) studies and in vivo PT treatment of cancer diseases. Among the different materials, new plasmonic nanostructures based on Cu2-xS nanocrystals (NCs) are emerging as valuable alternatives to Au nanorods, nanostars and nanoshells, largely exploited as NIR absorbing nanoheaters. Even though Cu2-xS plasmonic properties are not linked to geometry, the role played by their size, shape and surface chemistry is expected to be fundamental for an efficient PT process. Here, Cu2-xS NCs coated with a hydrophilic mesoporous silica shell (MSS) are synthesized by solution-phase strategies, tuning the core geometry, MSS thickness and texture. Besides their loading capability, the silica shell has been widely reported to provide a more robust plasmonic core protection than organic molecular/polymeric coatings, and improved heat flow from the NC to the environment due to a reduced interfacial thermal resistance and direct electron-phonon coupling through the interface. Systematic structural and morphological analysis of the core-shell nanoparticles and an in-depth thermoplasmonic characterization by using a pump beam 808 nm laser, are carried out. The results suggest that large triangular nanoplates (NPLs) coated by a few tens of nanometers thick MSS, show good photostability under laser light irradiation and provide a temperature increase above 38 °C and a 20% PT efficiency upon short irradiation time (60 s) at 6 W/cm2 power density.

Nanotechnology-Assisted RNA Delivery: From Nucleic Acid Therapeutics to COVID-19 Vaccines.

In recent years, the main quest of science has been the pioneering of the groundbreaking biomedical strategies needed for achieving a personalized medicine. Ribonucleic acids (RNAs) are outstanding bioactive macromolecules identified as pivotal actors in regulating a wide range of biochemical pathways. The ability to intimately control the cell fate and tissue activities makes RNA-based drugs the most fascinating family of bioactive agents. However, achieving a widespread application of RNA therapeutics in humans is still a challenging feat, due to both the instability of naked RNA and the presence of biological barriers aimed at hindering the entrance of RNA into cells. Recently, material scientists' enormous efforts have led to the development of various classes of nanostructured carriers customized to overcome these limitations. This work systematically reviews the current advances in developing the next generation of drugs based on nanotechnology-assisted RNA delivery. The features of the most used RNA molecules are presented, together with the development strategies and properties of nanostructured vehicles. Also provided is an in-depth overview of various therapeutic applications of the presented systems, including coronavirus disease vaccines and the newest trends in the field. Lastly, emerging challenges and future perspectives for nanotechnology-mediated RNA therapies are discussed.

Stimuli-responsive nanoparticle-assisted immunotherapy: a new weapon against solid tumours.

Although significant improvements in cancer treatment have led to a longer survival period, the death rate of patients with solid tumours has not changed during the last decades. Most researchers are currently concentrating on defining the mechanisms of the different resistance pathways activated by tumour cells; meanwhile, the role of limited drug distribution within tumours has been neglected. The application of nanotechnology in medicine offers unexplored opportunities for realizing a new generation of anticancer therapies that can overcome the physical hindrances that characterize solid tumours. Indeed, surface-engineered nanoparticles (NPs) (both organic and inorganic) have been used as powerful tools in cancer therapy. Particularly, Au NPs have been utilized to develop a new drug-free treatment, photo-thermal therapy (PTT), due to their stimuli-responsive properties. PTT combined with immunotherapy represents a major breakthrough in the fight against malignant solid tumours. In this review, we provide a complete overview of the synergistic approaches based on PTT and immunotherapy, considering the selection, design, and functionalization of the NPs and their thermo-optical properties, moving to in vivo studies and finally to clinical trial applications in patients suffering from solid tumours.

Scalable Synthesis of Mesoporous TiO2 for Environmental Photocatalytic Applications.

Increasing environmental concern, related to pollution and clean energy demand, have urged the development of new smart solutions profiting from nanotechnology, including the renowned nanomaterial-assisted photocatalytic degradation of pollutants. In this framework, increasing efforts are devoted to the development of TiO2-based nanomaterials with improved photocatalytic activity. A plethora of synthesis routes to obtain high quality TiO2-based nanomaterials is currently available. Nonetheless, large-scale production and the application of nanosized TiO2 is still hampered by technological issues and the high cost related to the capability to obtain TiO2 nanoparticles with high reaction yield and adequate morphological and structural control. The present review aims at providing a selection of synthetic approaches suitable for large-scale production of mesoporous TiO2-based photocatalysts due to its unique features including high specific surface area, improved ultraviolet (UV) radiation absorption, high density of surface hydroxyl groups, and significant ability for further surface functionalization The overviewed synthetic strategies have been selected and classified according to the following criteria (i) high reaction yield, (ii) reliable synthesis scale-up and (iii) adequate control over morphological, structural and textural features. Potential environmental applications of such nanostructures including water remediation and air purification are also discussed.

Thermo-Plasmonic Killing of Escherichia coli TG1 Bacteria.

Plasmonic photo-thermal therapy (PPTT) is a minimally invasive, drug-free, therapy based on the properties of noble metal nanoparticles, able to convert a bio-transparent electromagnetic radiation into heat. PPTT has been used against cancer and other diseases. Herein, we demonstrate an antimicrobial methodology based on the properties of gold nanorods (GNRs). Under a resonant laser irradiation GNRs become highly efficient light to heat nano-converters extremely useful for PPTT applications. The concept here is to assess the antimicrobial effect of easy to synthesize, suitably purified, water-dispersible GNRs on Escherichia coli bacteria. A control on the GNRs concentration used for the process has been demonstrated critical in order to rule out cytotoxic effects on the cells, and still to be able to generate, under a near infrared illumination, an adequate amount of heat suited to increase the temperature up to ≈50 °C in about 5 min. Viability experiments evidenced that the proposed system accomplished a killing efficiency suitable to reducing the Escherichia coli population of about 2 log CFU (colony-forming unit).