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Radiotherapy (RT) involves delivering X-ray beams to the tumor site to trigger DNA damage. In this approach, it is fundamental to preserve healthy cells and to confine the X-ray beam only to the malignant cells. The integration of gold nanoparticles (AuNPs) in the X-ray methodology could be considered a powerful tool to improve the efficacy of RT. Indeed, AuNPs have proven to be excellent allies in contrasting tumor pathology upon RT due to their high photoelectric absorption coefficient and unique physiochemical properties. However, an analysis of their physical and morphological reaction to X-ray exposure is necessary to fully understand the AuNPs’ behavior upon irradiation before treating the cells, since there are currently no studies on the evaluation of potential NP morphological changes upon specific irradiations. In this work, we synthesized two differently shaped AuNPs adopting two different techniques to achieve either spherical or star-shaped AuNPs. The spherical AuNPs were obtained with the Turkevich–Frens method, while the star-shaped AuNPs (AuNSs) involved a seed-mediated approach. We then characterized all AuNPs with Transmission Electron Microscopy (TEM), Uv-Vis spectroscopy, Dynamic Light Scattering (DLS), zeta potential and Fourier Transform Infrared (FTIR) spectroscopy. The next step involved the treatment of AuNPs with two different doses of X-radiation commonly used in RT, namely 1.8 Gy and 2 Gy, respectively. Following the X-rays’ exposure, the AuNPs were further characterized to investigate their possible physicochemical and morphological alterations induced with the X-rays. We found that AuNPs do not undergo any alteration, concluding that they can be safely used in RT treatments. Lastly, the actin rearrangements of THP-1 monocytes treated with AuNPs were also assessed in terms of coherency. This is a key proof to evaluate the possible activation of an immune response, which still represents a big limitation for the clinical translation of NPs.

Facile synthesis of metal nanoparticles with controlled physicochemical properties using environment-friendly reagents can open new avenues in biomedical applications. Nanomaterials with controlled physicochemical properties have opened new prospects for a variety of applications. In the present study, we report a single-step photochemical synthesis of ~5 nm-sized silver (Ag) and gold (Au) nanoparticles (NPs), and Ag–Au alloy nanoparticles using L-tyrosine. The physicochemical and surface properties of both monometallic and bimetallic NPs were investigated by analytical, spectroscopic, and microscopic techniques. Our results also displayed an interaction between L-tyrosine and surface atoms that leads to the formation of AgAu NPs by preventing the growth and aggregation of the NPs. This method efficiently produced monodispersed NPs, with a narrow-sized distribution and good stability in an aqueous solution. The cytotoxicity assessment performed on breast cancer cell lines (MCF-7) revealed that the biofriendly L-tyrosine-capped AgNPs, AuNPs, and bimetallic AgAu NPs were biocompatible. Interestingly, AgAu NPs have also unveiled controlled cytotoxicity, cell viability, and in vitro peroxidase nanozyme activity reliant on metal composition and surface coating.

In recent years, Atomic Force Microscope (AFM)-based nanolithography techniques have emerged as a very powerful approach for the machining of countless types of nanostructures. However, the conventional AFM-based nanolithography methods suffer from low efficiency, low rate of patterning, and high complexity of execution. In this frame, we first developed an easy and effective nanopatterning technique, termed Pulse-Atomic Force Lithography (P-AFL), with which we were able to pattern 2.5D nanogrooves on a thin polymer layer. Indeed, for the first time, we patterned nanogrooves with either constant or varying depth profiles, with sub-nanometre resolution, high accuracy, and reproducibility. In this paper, we present the results on the investigation of the effects of P-AFL parameters on 2.5D nanostructures’ morphology. We considered three main P-AFL parameters, i.e., the pulse’s amplitude (setpoint), the pulses’ width, and the distance between the following indentations (step), and we patterned arrays of grooves after a precise and well-established variation of the aforementioned parameters. Optimizing the nanolithography process, in terms of patterning time and nanostructures quality, we realized unconventional shape nanostructures with high accuracy and fidelity. Finally, a scanning electron microscope was used to confirm that P-AFL does not induce any damage on AFM tips used to pattern the nanostructures.

Neurodegenerative disorders (NDs) affect a great number of people worldwide and also have a significant socio-economic impact on the aging population. In this context, nanomedicine applied to neurological disorders provides several biotechnological strategies and nanoformulations that improve life expectancy and the quality of life of patients affected by brain disorders. However, available treatments are limited by the presence of the blood–brain barrier (BBB) and the blood–cerebrospinal fluid barrier (B–CSFB). In this regard, nanotechnological approaches could overcome these obstacles by updating various aspects (e.g., enhanced drug-delivery efficiency and bioavailability, BBB permeation and targeting the brain parenchyma, minimizing side effects). The aim of this review is to carefully explore the key elements of different neurological disorders and summarize the available nanomaterials applied for neurodegeneration therapy looking at several types of nanocarriers. Moreover, nutraceutical-loaded nanoparticles (NPs) and synthesized NPs using green approaches are also discussed underling the need to adopt eco-friendly procedures with a low environmental impact. The proven antioxidant properties related to several natural products provide an interesting starting point for developing efficient and green nanotools useful for neuroprotection.

The increasingly widespread use of engineered nanomaterials in many applications increases the need to understand the mechanisms behind their toxicity [...]

The widespread use of nanotechnology in different application fields, resulting in the integration of nanostructures in a plethora of devices, has addressed the research toward novel and easy-to-setup nanofabrication techniques to realize nanostructures with high spatial resolution and reproducibility. Owing to countless applications in molecular electronics, data storage, nanoelectromechanical, and systems for the Internet of Things, in recent decades, the scientific community has focused on developing methods suitable for nanopattern polymers. To this purpose, Atomic Force Microscopy-based nanolithographic techniques are effective methods that are relatively less complex and inexpensive than equally resolute and accurate techniques, such as Electron Beam lithography and Focused Ion Beam lithography. In this work, we propose an evolution of nanoindentation, named Pulse-Atomic Force Microscopy, to obtain continuous structures with a controlled depth profile, either constant or variable, on a polymer layer. Due to the modulation of the characteristics of voltage pulses fed to the AFM piezo-scanner and distance between nanoindentations, it was possible to indent sample surface with high spatial control and fabricate highly resolved 2.5D nanogrooves. That is the real strength of the proposed technique, as no other technique can achieve similar results in tailor-made graded nanogrooves without the need for additional manufacturing steps.

Over the last decades, several materials have been proposed for the fabrication of dental and mandibular prosthetic implants. Today, the poly(methyl-methacrylate) (PMMA) resin is the most spread material, due to its ease of processing, low cost, aesthetic properties, low weight, biocompatibility, and biostability in the oral cavity. However, the porous surface (which favors the adhesion of microorganisms) and the weak mechanical properties (which lead to wear or fracture) are the major concerns. The inclusion of engineered nanomaterials in the acrylic matrix could improve the performances of PMMA. In this study, we added two different kind of nanomaterials, namely titanium dioxide nanoparticles (TiO2NPs) and halloysite clay nanotubes (HNTs) at two concentrations (1% and 3% w/w) in PMMA. Then, we assessed the effect of nanomaterials inclusion by the evaluation of specific physical parameters: Young’s modulus, roughness, and wettability. In addition, we investigated the potential beneficial effects regarding the Candida albicans (C. albicans) colonization reduction, the most common yeast responsible of several infections in oral cavity. Our experimental results showed an improvement of PMMA performance, following the addition of TiO2NPs and HNTs, in a dose dependent manner. In particular, the presence of TiO2NPs in the methacrylate matrix induced a greater increase in PMMA stiffness respect to HNTs addition. On the other hand, HNTs reduced the rate of C. albicans colonization more significantly than TiO2NPs. The results obtained are of great interest for the improvement of PMMA physico-chemical properties, in view of its possible application in clinical dentistry.

Nanoparticles of Human Serum Albumin (NC) labelled with 99mTc are widely used in Nuclear Medicine and represent the gold-standard for the intraoperative detection of the sentinel lymph node in many kinds of cancer, mainly breast cancer and melanoma. A significant amount of radionuclides can be incorporated into the HSA particle, due to the multiple binding sites, and HSA-based nanocolloid catabolism is a fast and easy process that results in innocuous degradation products. NCs labelled with different isotopes represent an interesting radiopharmaceutical for extending diagnostic accuracy and surgical outcome, but the knowledge of the chemical bond between NCs and isotopes has not been fully elucidated, including information on its strength and specificity. The aim of this study is to investigate and compare the physicochemical characteristics of the bond between NCs and 99mTc and 68Ga isotopes. Commercial kits of HSA-based nanocolloid particles (NanoAlbumon®) were used. For this purpose, we have primarily studied the kinetic orders of NC radiolabelling. Langmuir isotherms and pH effect on radiolabelling were tested and the stability of the radiometal complex was verified through competition reactions carried out in presence of different ligands. The future goal of our research is the development of inexpensive and instant kits, easily labelled with a wide spectrum of diagnostic and therapeutic isotopes, thus facilitating the availability of versatile and multipurpose radiopharmaceuticals.

Heavy metal ions and pesticides are extremely dangerous for human health and environment and an accurate detection is an essential step to monitor their levels in water. The standard and most used methods for detecting these pollutants are sophisticated and expensive analytical techniques. However, recent technological advancements have allowed the development of alternative techniques based on optical properties of noble metal nanomaterials, which provide many advantages such as ultrasensitive detection, fast turnover, simple protocols, in situ sampling, on-site capability and reduced cost. This paper provides a review of the most common photo-physical effects impact on the fluorescence of metal nanomaterials and how these processes can be exploited for the detection of pollutant species. The final aim is to provide readers with an updated guide on fluorescent metallic nano-systems used as optical sensors of heavy metal ions and pesticides in water.

In the last years, there is a growing interest in the application of nanoscaled materials in cancer therapy because of their unique physico-chemical properties. However, the dark side of their usability is limited by their possible toxic behaviour and accumulation in living organisms. Starting from this assumption, the search for a green alternative to produce nanoparticles (NPs) or the discovery of green molecules, is a challenge in order to obtain safe materials. In particular, gold (Au NPs) and silver (Ag NPs) NPs are particularly suitable because of their unique physico-chemical properties, in particular plasmonic behaviour that makes them useful as active anticancer agents. These NPs can be obtained by green approaches, alternative to conventional chemical methods, owing to the use of phytochemicals, carbohydrates, and other biomolecules present in plants, fungi, and bacteria, reducing toxic effects. In addition, we analysed the use of green and stimuli-responsive polymeric bio-inspired nanovesicles, mainly used in drug delivery applications that have revolutionised the way of drugs supply. Finally, we reported the last examples on the use of metallic and Au NPs as self-propelling systems as new concept of nanorobot, which are able to respond and move towards specific physical or chemical stimuli in biological entities.

The green synthesis of nanoparticles (NPs) is currently under worldwide investigation as an eco-friendly alternative to traditional routes (NPs): the absence of toxic solvents and catalysts make it suitable in the design of promising nanomaterials for nanomedicine applications. In this work, we used the extracts collected from leaves of two cultivars (Leccino and Carolea) belonging to the species Olea Europaea, to synthesize silver NPs (AgNPs) in different pH conditions and low temperature. NPs underwent full morphological characterization with the aim to define a suitable protocol to obtain a monodispersed population of AgNPs. Afterwards, to validate the reproducibility of the mentioned synthetic procedure, we moved on to another Mediterranean plant, the Laurus Nobilis. Interestingly, the NPs obtained using the two olive cultivars produced NPs with different shape and size, strictly depending on the cultivar selected and pH. Furthermore, the potential ability to inhibit the growth of two woman cancer cells (breast adenocarcinoma cells, MCF-7 and human cervical epithelioid carcinoma, HeLa) were assessed for these AgNPs, as well as their capability to mitigate the bacteria concentration in samples of contaminated well water. Our results showed that toxicity was stronger when MCF-7 and Hela cells were exposed to AgNPs derived from Carolea obtained at pH 7 presenting irregular shape; on the other hand, greater antibacterial effect was revealed using AgNPs obtained at pH 8 (smaller and monodispersed) on well water, enriched with bacteria and coliforms.

Silver nanoparticles capped with 3-mercapto-1propanesulfonic acid sodium salt (AgNPs-3MPS), able to interact with Ni2+ or Co2+, have been prepared to detect these heavy metal ions in water. This system works as an optical sensor and it is based on the change of the intensity and shape of optical absorption peak due to the surface plasmon resonance (SPR) when the AgNPs-3MPS are in presence of metals ions in a water solution. We obtain a specific sensitivity to Ni2+ and Co2+ up to 500 ppb (part per billion). For a concentration of 1 ppm (part per million), the change in the optical absorption is strong enough to produce a colorimetric effect on the solution, easily visible with the naked eye. In addition to the UV-VIS characterizations, morphological and dimensional studies were carried out by transmission electron microscopy (TEM). Moreover, the systems were investigated by means of dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and high-resolution X-ray photoelectron spectroscopy (HR-XPS). On the basis of the results, the mechanism responsible for the AgNPs-3MPS interaction with Ni2+ and Co2+ (in the range of 0.5–2.0 ppm) looks like based on the coordination compounds formation.

The large use of nanomaterials in many fields of application and commercial products highlights their potential toxicity on living organisms and the environment, despite their physico-chemical properties. Among these, silver nanoparticles (Ag NPs) are involved in biomedical applications such as antibacterial agents, drug delivery vectors and theranostics agents. In this review, we explain the common synthesis routes of Ag NPs using physical, chemical, and biological methods, following their toxicity mechanism in cells. In particular, we analyzed the physiological cellular pathway perturbations in terms of oxidative stress induction, mitochondrial membrane potential alteration, cell death, apoptosis, DNA damage and cytokines secretion after Ag NPs exposure. In addition, their potential anti-cancer activity and theranostic applications are discussed.