Surgery Plays a Leading Role in Breast Cancer Treatment for Patients Aged ≥90 Years: A Large Retrospective Cohort Study.

BACKGROUND: The population aged ≥90 years is increasing worldwide, yet nearly 50% of elderly breast cancer (BC) patients receive suboptimal treatments, resulting in high rates of BC-related mortality. We analyzed clinical and survival outcomes of nonagenarian BC patients to identify effective treatment strategies. METHODS: This single-institution retrospective cohort study analyzed patients aged ≥90 years diagnosed with stage I-III BC between 2007 and 2018. Patients were categorized into three treatment groups: traditional surgery (TS), performed according to local guidelines; current-standard surgery (CS), defined as breast surgery without axillary surgery (in concordance with 2016 Choosing Wisely guidelines) and/or cavity shaving; and non-surgical treatment (NS). Clinicopathological features were recorded and recurrence rates and survival outcomes were analyzed. RESULTS: We collected data from 113 nonagenarians with a median age of 93 years (range 90-99). Among these patients, 43/113 (38.1%) underwent TS, 34/113 (30.1%) underwent CS, and 36/113 (31.9%) underwent NS. The overall recurrence rate among surgical patients was 10.4%, while the disease progression rate in the NS group was 22.2%. Overall survival was significantly longer in surgical patients compared with NS patients (p = 0.04). BC-related mortality was significantly higher in the NS group than in the TS and CS groups (25.0% vs. 0% vs. 7.1%, respectively; p = 0.01). There were no significant differences in overall survival and disease-free survival between the TS and CS groups (p = 0.6 and p = 0.8, respectively), although the TS group experienced a significantly higher overall postoperative complication rate (p < 0.001). CONCLUSIONS: Individualized treatment planning is essential for nonagenarian BC patients. Surgery, whenever feasible, remains the treatment of choice, with CS emerging as the best option for the majority of patients.

Intraoperative Ultrasound-Guided Conserving Surgery for Breast Cancer: No More Time for Blind Surgery.

BACKGROUND: Breast-conserving surgery (BCS) still remains a blind surgery despite all available tumor localization methods. Intraoperative ultrasound (IOUS) allows real-time visualization during all resection phases. METHODS: This was a prospective observational cohort study conducted at the Veneto Institute of Oncology between January 2021 and June 2022. Patients with ductal carcinoma in situ, T1-2 invasive cancer, or post-neoadjuvant tumors, suitable for BCS, were recruited. All breast cancer lesion types were included, i.e. solid palpable, solid non-palpable, non-solid non-palpable, and post-neoadjuvant treatment residual lesions. Eligible participants were randomly assigned to either IOUS or traditional surgery (TS) in a 1:1 ratio. The main outcomes were surgical margin involvement, reoperation rate, closest margin width, main specimen and cavity shaving margin volumes, excess healthy tissue removal, and calculated resection ratio (CRR). RESULTS: Overall, 160 patients were enrolled: 80 patients were allocated to the TS group and 80 to the IOUS group. IOUS significantly reduced specimen volumes (16.8 cm3 [10.5-28.9] vs. 24.3 cm3 [15.0-41.3]; p = 0.015), with wider closest resection margin width (2.0 mm [1.0-4.0] vs. 1.0 mm [0.5-2.0] after TS; p < 0.001). Tumor volume to specimen volume ratio was significantly higher after IOUS (4.7% [2.5-9.1] vs. 2.9% [0.8-5.2]; p < 0.001). IOUS yielded significantly better CRR (84.5% [46-120.8] vs. 114% [81.8-193.2] after TS; p < 0.001), lower involved margin rate (2.5 vs. 15%; p = 0.009) and reduced re-excision rate (2.5 vs. 12.5%; p = 0.032). CONCLUSIONS: IOUS allows real-time resection margin visualization and continuous control during BCS. It showed clear superiority over TS in both oncological and surgical outcomes for all breast cancer lesion types. These results disfavor the paradigm of blind breast surgery.

A Study of the Radiation Tolerance and Timing Properties of 3D Diamond Detectors.

We present a study on the radiation tolerance and timing properties of 3D diamond detectors fabricated by laser engineering on synthetic Chemical Vapor Deposited (CVD) plates. We evaluated the radiation hardness of the sensors using Charge Collection Efficiency (CCE) measurements after neutron fluences up to 1016 n/cm2 (1 MeV equivalent.) The radiation tolerance is significantly higher when moving from standard planar architecture to 3D architecture and increases with the increasing density of the columnar electrodes. Also, the maximum applicable bias voltage before electric breakdown increases significantly after high fluence irradiation, possibly due to the passivation of defects. The experimental analysis allowed us to predict the performance of the devices at higher fluence levels, well in the range of 1016 n/cm2. We summarize the recent results on the time resolution measurements of our test sensors after optimization of the laser fabrication process and outline future activity in developing pixel tracking systems for high luminosity particle physics experiments.

Graphene Oxide: A Smart (Starting) Material for Natural Methylxanthines Adsorption and Detection.

Natural methylxanthines, caffeine, theophylline and theobromine, are widespread biologically active alkaloids in human nutrition, found mainly in beverages (coffee, tea, cocoa, energy drinks, etc.). Their detection is thus of extreme importance, and many studies are devoted to this topic. During the last decade, graphene oxide (GO) and reduced graphene oxide (RGO) gained popularity as constituents of sensors (chemical, electrochemical and biosensors) for methylxanthines. The main advantages of GO and RGO with respect to graphene are the easiness and cheapness of synthesis, the notable higher solubility in polar solvents (water, among others), and the higher reactivity towards these targets (mainly due to - interactions); one of the main disadvantages is the lower electrical conductivity, especially when using them in electrochemical sensors. Nonetheless, their use in sensors is becoming more and more common, with the obtainment of very good results in terms of selectivity and sensitivity (up to 5.4 × 10-10 mol L-1 and 1.8 × 10-9 mol L-1 for caffeine and theophylline, respectively). Moreover, the ability of GO to protect DNA and RNA from enzymatic digestion renders it one of the best candidates for biosensors based on these nucleic acids. This is an up-to-date review of the use of GO and RGO in sensors.

Numerical simulation of ISFET structures for biosensing devices with TCAD tools.

BACKGROUND: Ion Sensitive Field Effect Transistors (ISFETs) are one of the primitive structures for the fabrication of biosensors (BioFETs). Aiming at the optimization of the design and fabrication processes of BioFETs, the correlation between technological parameters and device electrical response can be obtained by means of an electrical device-level simulation. In this work we present a numerical simulation approach to the study of ISFET structures for bio-sensing devices (BioFET) using Synopsys Sentaurus Technology Computer-Aided Design (TCAD) tools. METHODS: The properties of a custom-defined material were modified in order to reproduce the electrolyte behavior. In particular, the parameters of an intrinsic semiconductor material have been set in order to reproduce an electrolyte solution. RESULTS: The electrostatic behaviour (transfer characteristics) of a general BioFET structure has been simulated when the captured target number increases from 1 to 10. The ID current as a function of the VDS voltage for different positions of a single charged block and for different values of the reference electrode have been calculated. CONCLUSIONS: We presented a numerical simulation approach to the study of Ion-Sensitive Field Effect Transistor (ISFET) structures for biosensing devices (BioFETs) using the Synopsys Sentaurus Technology Computer-Aided Design (TCAD) tools. A powerful framework for the design and optimization of biosensor has been devised, thus helping in reducing technology development time and cost. The main finding of the analysis of a general reference BioFET shows that there is no linear relationship between the number of charges and the current modulation. Actually, there is a strong position dependent effect: targets localized near the source region are most effective with respect to targets localized near the drain region. In general, even randomly distributed targets are more efficient with respect to locally grouped targets on the current modulation. Moreover, for the device at hand, a small positive biasing of the electrolyte solution, providing that the transistor goes on, will result in a greater enhancement of the current levels, still retaining a good sensitivity but greatly simplifying the operations of a real device.

Strained Silicon Technology: Non-Destructive High-Lateral-Resolution Characterization Through Tip-Enhanced Raman Spectroscopy.

The semiconductor industry is undergoing a transformative phase, marked by the relentless drive for miniaturization and a constant demand for higher performance and energy efficiency. However, the reduction of metal-oxide-semiconductor field-effect transistor sizes for advanced technology nodes below 10 nm presents several challenges. In response, strained silicon technology has emerged as a key player, exploiting strain induction in the silicon crystal lattice to improve device performance. At the same time, there has been a growing need for characterization techniques that allow in-line monitoring of sample conditions during semiconductor manufacturing, as an alternative to traditional methods such as transmission electron microscopy or high-resolution X-ray diffraction, which have several limitations in terms of measurement time and sample destructiveness. This paper explores the application of advanced spectroscopic characterization techniques, in particular µ-Raman spectroscopy and tip-enhanced Raman spectroscopy (TERS), to meet the evolving needs of the semiconductor industry for quality control and failure analysis, increasingly requiring faster and non-destructive characterization techniques. µ-Raman provides insight into strain values and distributions of strained layers with different thicknesses and germanium concentrations, but its lateral resolution is constrained by the Abbe diffraction limit. TERS, on the other hand, emerges as a powerful non-destructive technique capable of overcoming diffraction limits by exploiting the combination of an atomic force microscope with a Raman spectrometer. This breakthrough makes it possible to estimate the chemical composition and induced strain in the lattice by evaluating the Raman peak position shifts in strained and unstrained silicon layers, providing crucial insights for nanoscale strain control. In particular, this paper focuses on the TERS characterization of Si0.7Ge0.3 epitaxial layers grown on a silicon-on-insulator device, demonstrating the effectiveness of this technique and the high lateral resolution that can be achieved.

Toward the nanoscale chemical and physical probing of milk-derived extracellular vesicles using Raman and tip-enhanced Raman spectroscopy.

Tip-enhanced Raman spectroscopy (TERS) is an advanced technique to perform local chemical analysis of the surface of a sample through the improvement of the sensitivity and the spatial resolution of Raman spectroscopy by plasmonic enhancement of the electromagnetic signal in correspondence with the nanometer-sized tip of an atomic force microscope (AFM). In this work, TERS is demonstrated to represent an innovative and powerful approach for studying extracellular vesicles, in particular bovine milk-derived extracellular vesicles (mEVs), which are nanostructures with considerable potential in drug delivery and therapeutic applications. Raman spectroscopy has been used to analyze mEVs at the micrometric and sub-micrometric scales to obtain a detailed Raman spectrum in order to identify the 'signature' of mEVs in terms of their characteristic molecular vibrations and, therefore, their chemical compositions. With the ability to improve lateral resolution, TERS has been used to study individual mEVs, demonstrating the possibility of investigating a single mEV selected on the surface of the sample and, moreover, analyzing specific locations on the selected mEV with nanometer lateral resolution. TERS potentially allows one to reveal local differences in the composition of mEVs providing new insights into their structure. Also, thanks to the intrinsic properties of TERS to acquire the signal from only the first few nanometers of the surface, chemical investigation of the lipid membrane in correspondence with the various locations of the selected mEV could be performed by analyzing the peaks of the Raman shift in the relevant range of the spectrum (2800-3000 cm-1). Despite being limited to mEVs, this work demonstrates the potential of TERS in the analysis of extracellular vesicles.

Dosimetry of microbeam radiotherapy by flexible hydrogenated amorphous silicon detectors.

Objective.Detectors that can provide accurate dosimetry for microbeam radiation therapy (MRT) must possess intrinsic radiation hardness, a high dynamic range, and a micron-scale spatial resolution. In this work we characterize hydrogenated amorphous silicon detectors for MRT dosimetry, presenting a novel combination of flexible, ultra-thin and radiation-hard features.Approach.Two detectors are explored: an n-type/intrinsic/p-type planar diode (NIP) and an NIP with an additional charge selective layer (NIP + CSC).Results.The sensitivity of the NIP + CSC detector was greater than the NIP detector for all measurement conditions. At 1 V and 0 kGy under the 3T Cu-Cu synchrotron broadbeam, the NIP + CSC detector sensitivity of (7.76 ± 0.01) pC cGy-1outperformed the NIP detector sensitivity of (3.55 ± 0.23) pC cGy-1by 219%. The energy dependence of both detectors matches closely to the attenuation coefficient ratio of silicon against water. Radiation damage measurements of both detectors out to 40 kGy revealed a higher radiation tolerance in the NIP detector compared to the NIP + CSC (17.2% and 33.5% degradations, respectively). Percentage depth dose profiles matched the PTW microDiamond detector's performance to within ±6% for all beam filtrations except in 3T Al-Al due to energy dependence. The 3T Cu-Cu microbeam field profile was reconstructed and returned microbeam width and peak-to-peak values of (51 ± 1)µm and (405 ± 5)µm, respectively. The peak-to-valley dose ratio was measured as a function of depth and agrees within error to the values obtained with the PTW microDiamond. X-ray beam induced charge mapping of the detector revealed minimal dose perturbations from extra-cameral materials.Significance.The detectors are comparable to commercially available dosimeters for quality assurance in MRT. With added benefits of being micron-sized and possessing a flexible water-equivalent substrate, these detectors are attractive candidates for quality assurance,in-vivodosimetry and in-line beam monitoring for MRT and FLASH therapy.

Characterization of a flexible a-Si:H detector for in vivo dosimetry in therapeutic x-ray beams.

BACKGROUND: The increasing use of complex and high dose-rate treatments in radiation therapy necessitates advanced detectors to provide accurate dosimetry. Rather than relying on pre-treatment quality assurance (QA) measurements alone, many countries are now mandating the use of in vivo dosimetry, whereby a dosimeter is placed on the surface of the patient during treatment. Ideally, in vivo detectors should be flexible to conform to a patient's irregular surfaces. PURPOSE: This study aims to characterize a novel hydrogenated amorphous silicon (a-Si:H) radiation detector for the dosimetry of therapeutic x-ray beams. The detectors are flexible as they are fabricated directly on a flexible polyimide (Kapton) substrate. METHODS: The potential of this technology for application as a real-time flexible detector is investigated through a combined dosimetric and flexibility study. Measurements of fundamental dosimetric quantities were obtained including output factor (OF), dose rate dependence (DPP), energy dependence, percentage depth dose (PDD), and angular dependence. The response of the a-Si:H detectors investigated in this study are benchmarked directly against commercially available ionization chambers and solid-state diodes currently employed for QA practices. RESULTS: The a-Si:H detectors exhibit remarkable dose linearities in the direct detection of kV and MV therapeutic x-rays, with calibrated sensitivities ranging from (0.580 ± 0.002) pC/cGy to (19.36 ± 0.10) pC/cGy as a function of detector thickness, area, and applied bias. Regarding dosimetry, the a-Si:H detectors accurately obtained OF measurements that parallel commercially available detector solutions. The PDD response closely matched the expected profile as predicted via Geant4 simulations, a PTW Farmer ionization chamber and a PTW ROOS chamber. The most significant variation in the PDD performance was 5.67%, observed at a depth of 3 mm for detectors operated unbiased. With an external bias, the discrepancy in PDD response from reference data was confined to ± 2.92% for all depths (surface to 250 mm) in water-equivalent plastic. Very little angular dependence is displayed between irradiations at angles of 0° and 180°, with the most significant variation being a 7.71% decrease in collected charge at a 110° relative angle of incidence. Energy dependence and dose per pulse dependence are also reported, with results in agreement with the literature. Most notably, the flexibility of a-Si:H detectors was quantified for sample bending up to a radius of curvature of 7.98 mm, where the recorded photosensitivity degraded by (-4.9 ± 0.6)% of the initial device response when flat. It is essential to mention that this small bending radius is unlikely during in vivo patient dosimetry. In a more realistic scenario, with a bending radius of 15-20 mm, the variation in detector response remained within ± 4%. After substantial bending, the detector's photosensitivity when returned to a flat condition was (99.1 ± 0.5)% of the original response. CONCLUSIONS: This work successfully characterizes a flexible detector based on thin-film a-Si:H deposited on a Kapton substrate for applications in therapeutic x-ray dosimetry. The detectors exhibit dosimetric performances that parallel commercially available dosimeters, while also demonstrating excellent flexibility results.

Mechanical characterization of polymeric thin films by atomic force microscopy based techniques.

Polymeric thin films have been awakening continuous and growing interest for application in nanotechnology. For such applications, the assessment of their (nano)mechanical properties is a key issue, since they may dramatically vary between the bulk and the thin film state, even for the same polymer. Therefore, techniques are required for the in situ characterization of mechanical properties of thin films that must be nondestructive or only minimally destructive. Also, they must also be able to probe nanometer-thick ultrathin films and layers and capable of imaging the mechanical properties of the sample with nanometer lateral resolution, since, for instance, at these scales blends or copolymers are not uniform, their phases being separated. Atomic force microscopy (AFM) has been proposed as a tool for the development of a number of techniques that match such requirements. In this review, we describe the state of the art of the main AFM-based methods for qualitative and quantitative single-point measurements and imaging of mechanical properties of polymeric thin films, illustrating their specific merits and limitations.

Upscaling of Electrospinning Technology and the Application of Functionalized PVDF-HFP@TiO2 Electrospun Nanofibers for the Rapid Photocatalytic Deactivation of Bacteria on Advanced Face Masks.

In recent years, Electrospinning (ES) has been revealed to be a straightforward and innovative approach to manufacture functionalized nanofiber-based membranes with high filtering performance against fine Particulate Matter (PM) and proper bioactive properties. These qualities are useful for tackling current issues from bacterial contamination on Personal Protective Equipment (PPE) surfaces to the reusability of both disposable single-use face masks and respirator filters. Despite the fact that the conventional ES process can be upscaled to promote a high-rate nanofiber production, the number of research works on the design of hybrid materials embedded in electrospun membranes for face mask application is still low and has mainly been carried out at the laboratory scale. In this work, a multi-needle ES was employed in a continuous processing for the manufacturing of both pristine Poly (Vinylidene Fluoride-co-Hexafluoropropylene) (PVDF-HFP) nanofibers and functionalized membrane ones embedded with TiO2 Nanoparticles (NPs) (PVDF-HFP@TiO2). The nanofibers were collected on Polyethylene Terephthalate (PET) nonwoven spunbond fabric and characterized by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy, and Atomic Force Microscopy (AFM) analysis. The photocatalytic study performed on the electrospun membranes proved that the PVDF-HFP@TiO2 nanofibers provide a significant antibacterial activity for both Staphylococcus aureus (~94%) and Pseudomonas aeruginosa (~85%), after only 5 min of exposure to a UV-A light source. In addition, the PVDF-HFP@TiO2 nanofibers exhibit high filtration efficiency against submicron particles (~99%) and a low pressure drop (~3 mbar), in accordance with the standard required for Filtering Face Piece masks (FFPs). Therefore, these results aim to provide a real perspective on producing electrospun polymer-based nanotextiles with self-sterilizing properties for the implementation of advanced face masks on a large scale.

Hydrogenated amorphous silicon high flux x-ray detectors for synchrotron microbeam radiation therapy.

Objective. Microbeam radiation therapy (MRT) is an alternative emerging radiotherapy treatment modality which has demonstrated effective radioresistant tumour control while sparing surrounding healthy tissue in preclinical trials. This apparent selectivity is achieved through MRT combining ultra-high dose rates with micron-scale spatial fractionation of the delivered x-ray treatment field. Quality assurance dosimetry for MRT must therefore overcome a significant challenge, as detectors require both a high dynamic range and a high spatial resolution to perform accurately.Approach. In this work, a series of radiation hard a-Si:H diodes, with different thicknesses and carrier selective contact configurations, have been characterised for x-ray dosimetry and real-time beam monitoring applications in extremely high flux beamlines utilised for MRT at the Australian Synchrotron.Results. These devices displayed superior radiation hardness under constant high dose-rate irradiations on the order of 6000 Gy s-1, with a variation in response of 10% over a delivered dose range of approximately 600 kGy. Dose linearity of each detector to x-rays with a peak energy of 117 keV is reported, with sensitivities ranging from (2.74 ± 0.02) nC/Gy to (4.96 ± 0.02) nC/Gy. For detectors with 0.8µm thick active a-Si:H layer, their operation in an edge-on orientation allows for the reconstruction of micron-size beam profiles (microbeams). The microbeams, with a nominal full-width-half-max of 50µm and a peak-to-peak separation of 400µm, were reconstructed with extreme accuracy. The full-width-half-max was observed as 55 ± 1µm. Evaluation of the peak-to-valley dose ratio and dose-rate dependence of the devices, as well as an x-ray induced charge (XBIC) map of a single pixel is also reported.Significance. These devices based on novel a-Si:H technology possess a unique combination of accurate dosimetric performance and radiation resistance, making them an ideal candidate for x-ray dosimetry in high dose-rate environments such as FLASH and MRT.

High-Resolution Photoemission Study of Neutron-Induced Defects in Amorphous Hydrogenated Silicon Devices.

In this paper, by means of high-resolution photoemission, soft X-ray absorption and atomic force microscopy, we investigate, for the first time, the mechanisms of damaging, induced by neutron source, and recovering (after annealing) of p-i-n detector devices based on hydrogenated amorphous silicon (a-Si:H). This investigation will be performed by mean of high-resolution photoemission, soft X-Ray absorption and atomic force microscopy. Due to dangling bonds, the amorphous silicon is a highly defective material. However, by hydrogenation it is possible to reduce the density of the defect by several orders of magnitude, using hydrogenation and this will allow its usage in radiation detector devices. The investigation of the damage induced by exposure to high energy irradiation and its microscopic origin is fundamental since the amount of defects determine the electronic properties of the a-Si:H. The comparison of the spectroscopic results on bare and irradiated samples shows an increased degree of disorder and a strong reduction of the Si-H bonds after irradiation. After annealing we observe a partial recovering of the Si-H bonds, reducing the disorder in the Si (possibly due to the lowering of the radiation-induced dangling bonds). Moreover, effects in the uppermost coating are also observed by spectroscopies.

Current Nanocarrier Strategies Improve Vitamin B12 Pharmacokinetics, Ameliorate Patients' Lives, and Reduce Costs.

Vitamin B12 (VitB12) is a naturally occurring compound produced by microorganisms and an essential nutrient for humans. Several papers highlight the role of VitB12 deficiency in bone and heart health, depression, memory performance, fertility, embryo development, and cancer, while VitB12 treatment is crucial for survival in inborn errors of VitB12 metabolism. VitB12 is administrated through intramuscular injection, thus impacting the patients' lifestyle, although it is known that oral administration may meet the specific requirement even in the case of malabsorption. Furthermore, the high-dose injection of VitB12 does not ensure a constant dosage, while the oral route allows only 1.2% of the vitamin to be absorbed in human beings. Nanocarriers are promising nanotechnology that can enable therapies to be improved, reducing side effects. Today, nanocarrier strategies applied at VitB12 delivery are at the initial phase and aim to simplify administration, reduce costs, improve pharmacokinetics, and ameliorate the quality of patients' lives. The safety of nanotechnologies is still under investigation and few treatments involving nanocarriers have been approved, so far. Here, we highlight the role of VitB12 in human metabolism and diseases, and the issues linked to its molecule properties, and discuss how nanocarriers can improve the therapy and supplementation of the vitamin and reduce possible side effects and limits.

Acoustics and atomic force microscopy for the mechanical characterization of thin films.

The science and technology of thin films require the development of nondestructive methods for their quantitative mechanical characterization with nanometric spatial resolution. High-frequency ultrasonic techniques--especially acoustic microscopy--and atomic force microscopy (AFM) have been demonstrated to represent versatile tools for developing such methods. In particular, in the last 15 years, the combination of AFM, which can probe the surface of a sample by applying ultralow loads (from micronewtons down to piconewtons) with a micromachined tip having an apex radius of a few nanometers, and ultrasonics techniques led researchers to develop some unique tools which allow one to perform not only spot measurements of the sample elastic modulus, but also to obtain both the qualitative imaging of mechanical properties and the quantitative mapping of the elastic modulus of the sample surface with nanometric lateral resolution. In the present review, firstly a brief overview of the main ultrasound-based techniques for thin film characterization is reported. Then, some of the ultrasonic AFM techniques are described, emphasizing their capability of retrieving maps of both the tip-sample contact stiffness and the sample elastic modulus. Although these techniques are less affected by the mechanical properties of the substrates than standard indentation tests, a method for the correction of the substrate effect in ultrathin films is reported in detail. Finally, by probing the mechanical properties of a small portion of the sample volume underneath the tip, we illustrate the techniques as tools for the qualitative and quantitative characterization of variations in the adhesion between a thin film and a buried interface, as well as for detecting subsurface defects, voids, cracks, and dislocations.

Determination of Total Silicon and SiO2 Particles Using an ICP-MS Based Analytical Platform for Toxicokinetic Studies of Synthetic Amorphous Silica.

Synthetic amorphous silica (SAS), manufactured in pyrogenic or precipitated form, is a nanomaterial with a widespread use as food additive (E 551). Oral exposure to SAS results from its use in food and dietary supplements, pharmaceuticals and toothpaste. Recent evidence suggests that oral exposure to SAS may pose health risks and highlights the need to address the toxic potential of SAS as affected by the physicochemical characteristics of the different forms of SAS. For this aim, investigating SAS toxicokinetics is of crucial importance and an analytical strategy for such an undertaking is presented. The minimization of silicon background in tissues, control of contamination (including silicon release from equipment), high-throughput sample treatment, elimination of spectral interferences affecting inductively coupled plasma mass spectrometry (ICP-MS) silicon detection, and development of analytical quality control tools are the cornerstones of this strategy. A validated method combining sample digestion with silicon determination by reaction cell ICP-MS is presented. Silica particles are converted to soluble silicon by microwave dissolution with mixtures of HNO3, H2O2 and hydrofluoric acid (HF), whereas interference-free ICP-MS detection of total silicon is achieved by ion-molecule chemistry with limits of detection (LoDs) in the range 0.2-0.5 µg Si g-1 for most tissues. Deposition of particulate SiO2 in tissues is assessed by single particle ICP-MS.

Long-Lasting, Antinociceptive Effects of pH-Sensitive Niosomes Loaded with Ibuprofen in Acute and Chronic Models of Pain.

Ibuprofen is one of the non-steroidal anti-inflammatory drugs (NSAIDs) widely used to treat pain conditions. NSAIDs encounter several obstacles to passing across biological membranes. To overcome these constraints, we decided to study the effects of a new pH-sensitive formulation of niosomes containing Polysorbate 20 derivatized by Glycine and loaded with ibuprofen (NioIbu) in several animal models of pain in mice. We performed two tests commonly used to study acute antinociceptive activity, namely the writhing test and the capsaicin test. Our results demonstrated that NioIbu, administered 2 h before testing, reduced nociception, whereas the free form of ibuprofen was ineffective. In a model of inflammatory pain, hyperalgesia induced by zymosan, NioIbu induced a long-lasting reduction in hyperalgesia in treated mice. In a model of neuropathic pain induced by sciatic nerve chronic constriction, NioIbu reduced both neuropathy-induced allodynia and hyperalgesia. The results obtained in our experiments suggest that pH-sensitive niosomes containing Polysorbate 20 derivatized by Glycine is an effective model for NSAIDs delivery, providing durable antinociceptive effects and reducing the incidence of side effects.

Hydrophilic Silver Nanoparticles Loaded into Niosomes: Physical-Chemical Characterization in View of Biological Applications.

Silver nanoparticles (AgNPs) are widely used as antibacterial agents and anticancer drugs, but often their low stability limits their mass production and broad applications. The use of niosomes as a carrier to protect and envelop AgNPs gives a new perspective to solve these problems. In this study, AgNPs were functionalized with sodium 3-mercapto-1-propanesulfonate (3MPS) to induce hydrophilic behavior, improving loading in Tween 20 and Span 20 niosomes (NioTw20 and NioSp20, respectively). Entrapment efficiency was evaluated by UV analyses and is around 1-4%. Dimensions were investigated by means of dynamic light scattering (DLS) (<2RH> = 140 ± 4 nm and <2RH> = 251 ± 1 nm respectively for NioTw20 + AgNPs and NioSp20 + AgNPs) and were compared with those by atomic force microscopy (AFM) and small angle X ray scattering (SAXS) analyses. Stability was assessed in water up to 90 days, and both in bovine serum and human serum for up to 8 h. In order to characterize the local structure of niosomes, SAXS measurements have been performed on Tween 20 and Span 20 empty niosomes and loaded with AgNPs. The release profiles of hydrophilic probe calcein and lipophilic probe Nile Red were performed in HEPES buffer and in human serum. All these features contribute to conclude that the two systems, NioTw20 + AgNPs and NioSp20 + AgNPs, are suitable and promising in the field of biological applications.