Critical evaluation of the potential of ICP-MS-based systems in toxicological studies of metallic nanoparticles.

The extensive application of metallic nanoparticles (NPs) in several fields has significantly impacted our daily lives. Nonetheless, uncertainties persist regarding the toxicity and potential risks associated with the vast number of NPs entering the environment and human bodies, so the performance of toxicological studies are highly demanded. While traditional assays focus primarily on the effects, the comprehension of the underlying processes requires innovative analytical approaches that can detect, characterize, and quantify NPs in complex biological matrices. Among the available alternatives to achieve this information, mass spectrometry, and more concretely, inductively coupled plasma mass spectrometry (ICP-MS), has emerged as an appealing option. This work critically reviews the valuable contribution of ICP-MS-based techniques to investigate NP toxicity and their transformations during in vitro and in vivo toxicological assays. Various ICP-MS modalities, such as total elemental analysis, single particle or single-cell modes, and coupling with separation techniques, as well as the potential of laser ablation as a spatially resolved sample introduction approach, are explored and discussed. Moreover, this review addresses limitations, novel trends, and perspectives in the field of nanotoxicology, particularly concerning NP internalization and pathways. These processes encompass cellular uptake and quantification, localization, translocation to other cell compartments, and biological transformations. By leveraging the capabilities of ICP-MS, researchers can gain deeper insights into the behaviour and effects of NPs, which can pave the way for safer and more responsible use of these materials.

Investigation of the effect of pre-analytical factors on particle concentration and size in cryoprecipitate using nanoparticle tracking analysis.

BACKGROUND: Cryoprecipitate is used primarily to replenish fibrinogen levels in patients. Little is known about the presence of micro- or nano-sized particles in cryoprecipitate. Therefore, we aimed to quantify these particles and investigate some pre-analytical considerations. MATERIALS AND METHODS: Particle concentration and size distribution were determined in 10 cryoprecipitate units by nanoparticle tracking analysis (NTA). The effects of freeze-thawing cryoprecipitate and 0.45 µm filtration with either regenerated cellulose (RC) or polytetrafluoroethylene (PTFE) filters before sample analysis were examined. RESULTS: Neither the size nor concentration of particles were affected by two freeze/thaw cycles. PTFE filtration, but not RC filtration, significantly reduced particle mean and mode size compared to RC filtration and mode size compared to unfiltered cryoprecipitate. The 10 cryoprecipitate units had an average particle concentration of 2.50 × 1011 ± 1.10 × 1011 particles/mL, a mean particle size of 133.8 ± 7.5 nm and a mode particle size of 107.9 ± 11.1 nm. CONCLUSION: This study demonstrated that preanalytical filtration of cryoprecipitate units using RC filters was suitable for NTA. An additional freeze/thaw cycle did not impact NTA parameters, suggesting that aliquoting cryoprecipitate units prior to laboratory investigations is suitable for downstream analyses.

Nanotransportadores activos de cannabinoides para el tratamiento de la aterosclerosis / Active cannabinoid nanocarriers for the treatment of atherosclerosis

Con la intención de vehiculizar fármacos cannabinoides (agonistas CB2) de forma selectiva hacia la placa de ateroma, se han obtenido nanopartículas biocompatibles y biodegradables. Para ello, las nanopartículas PEGyladas, han sido funcionalizadas con un péptido capaz de unirse selectivamente a proteínas endoteliales de adhesión sobreexpresadas en la placa aterosclerótica (vascular cell adhesion molecule 1, VCAM-1). Las partículas han sido caracterizadas fisicoquímicamente, in vitro en cultivos celulares e in vivo en un modelo animal de aterosclerosis (ratones deficientes en apolipoproteína E, ApoE-/-), demostrando un óptimo control espacio-temporal de la liberación del cannabinoide y una respuesta farmacológica superior. Dado que los fármacos agonistas CB2 presentan alta lipofilia y baja disponibilidad, la introducción de nanosistemas selectivos para la vehiculización de estos fármacos antiaterogénicos, mejoraría su biodisponibilidad y eficacia.El trabajo presentado muestra parte de los resultados obtenidos de un proyecto previo. Estos resultados nos han avalado para la concesión de una nueva ayuda de financiación para abordar una estrategia más avanzada que implica la introducción de elementos de diagnóstico y de un fitocannabinoide. (AU)

In order to selectively deliver cannabinoid drugs (CB2 agonists) to the atherosclerotic plaque, biocompatible and biodegradable nanoparticles have been obtained. For this purpose, the PEGylated nanoparticles have been functionalized with a peptide capable of selectively binding to endothelial adhesion proteins overexpressed in the atherosclerotic plaque (vascular cell adhesion molecules 1, VCAM-1). The particles have been characterized physicochemically, in vitro in cell cultures and in vivo in an animal model of atherosclerosis (apolipoprotein E-deficient ApoE-/- mice), demonstrating optimal spatiotemporal control of cannabinoid release and superior pharmacological response. Given that CB2 agonist drugs present high lipophilicity and low availability, the introduction of selective nanosystems for the vehiculation of these antiatherogenic drugs would improve their bioavailability and efficacy.The work presented shows part of the results obtained from a previous project. These results have supported us for the award of a new funding grant to address a more advanced strategy involving the introduction of diagnostic elements and a phytocannabinoid. (AU)

Behaviour and fate of Ag-NPs, TiO2-NPs and ZnO-NPs in the human gastrointestinal tract: Biopersistence rate evaluation.

This study aims to provide information on the behaviour and biopersistence rate (BP) of metallic nanoparticles (Ag-NPs, TiO2-NPs, ZnO-NPs) naturally occurring in canned seafood and subjected to static in vitro digestion. Single particle ICP-MS analysis was performed to determine NPs distribution and concentrations in oral, gastric, and intestinal digests. Depending on the conditions of the digestive phase and the sample matrix, the phenomena of agglomeration and dispersion were highlighted and confirmed by Dynamic Light Scattering (DLS) technique. In standard suspensions, Ag-NPs had lower biopersistence (BP) than ZnO and TiO2-NPs (BP 34%, 89% and >100%, respectively). Among Ag-NPs and TiO2-NPs naturally present in the food matrix, those in canned tuna were more degradable than those in canned clam (BP Ag-NPs 36% vs. > 100%; BP TiO2-NPs 96% vs. > 100%), while BP ZnO-NPs showed high biopersistence in both seafood matrix (>100%). The biopersistence rates were higher than the recommended limit set by European Food Safety Authority (EFSA) (12%), referred to nanotechnologies to be applied in the food and feed chain, thus the investigated naturally occurring NPs cannot be considered readily degradable.

Nonmonotonic effect of CuO nanoparticles on medium-chain carboxylates production from waste activated sludge.

The growing applications of CuO nanoparticles (NPs) in industrial and agriculture has increased their concentrations in wastewater and subsequently accumulated in waste activated sludge (WAS), raising concerns about their impact on reutilization of WAS, especially on the medium-chain carboxylates (MCCs) production from anaerobic fermentation of WAS. Here we showed that CuO NPs at 10-50 mg/g-TS can significantly inhibit MCCs production, and reactive oxygen species generation was revealed to be the key factor linked to the phenomena. At lower CuO NPs concentrations (0.5-2.5 mg/g-TS), however, MCCs production was enhanced, with a maximum level of 37% compared to the control. The combination of molecular approaches and metaproteomic analysis revealed that although low dosage CuO NPs (2.5 mg/g-TS) weakly inhibited chain elongation process, they displayed contributive characteristics both in WAS solubilization and transport/metabolism of carbohydrate. These results demonstrated that the complex microbial processes for MCCs production in the anaerobic fermentation of WAS can be affected by CuO NPs in a dosage-dependent manner via regulating microbial protein expression level. Our findings can provide new insights into the influence of CuO NPs on anaerobic fermentation process and shed light on the treatment option for the resource utilization of CuO NPs polluted WAS.

Gallium Metal-Organic Nanoparticles with Albumin-Stabilized and Loaded Graphene for Enhanced Delivery to HCT116 Cells.

Background: Gallium (III) metal-organic complexes have been shown to have the ability to inhibit tumor growth, but the poor water solubility of many of the complexes precludes further application. The use of materials with high biocompatibility as drug delivery carriers for metal-organic complexes to enhance the bioavailability of the drug is a feasible approach. Methods: Here, we modified the ligands of gallium 8-hydroxyquinolinate complex with good clinical anticancer activity by replacing the 8-hydroxyquinoline ligands with 5-bromo-8-hydroxyquinoline (HBrQ), and the resulting Ga(III) + HBrQ complex had poor water solubility. Two biocompatible materials, bovine serum albumin (BSA) and graphene oxide (GO), were used to synthesize the corresponding Ga(III) + HBrQ complex nanoparticles (NPs) BSA/Ga/HBrQ NPs and GO/Ga/HBrQ NPs in different ways to enhance the drug delivery of the metal complex. Results: Both of BSA/Ga/HBrQ NPs and GO/Ga/HBrQ NPs can maintain stable existence in different solution states. In vitro cytotoxicity test showed that two nanomedicines had excellent anti-proliferation effect on HCT116 cells, which shown higher level of intracellular ROS and apoptosis ratio than that of cisplatin and oxaliplatin. In addition, the superior emissive properties of BSA/Ga/HBrQ NPs and GO/Ga/HBrQ NPs allow their use for in vivo imaging showing highly effective therapy in HCT116 tumor-bearing mouse models. Conclusion: The use of biocompatible materials for the preparation of NPs against poorly biocompatible metal-organic complexes to construct drug delivery systems is a promising strategy that can further improve drug delivery and therapeutic efficacy.

Finding the tiny plastic needle in the haystack: how field flow fractionation can help to analyze nanoplastics in food.

While the exact health risks associated with nanoplastics are currently the focus of intense research, there is no doubt that humans are exposed to nanoplastics and that food could be a major source of exposure. Nanoplastics are released from plastic materials and articles used during food production, processing, storage, preparation, and serving. They are also likely to enter the food chain via contaminated water, air, and soil. However, very limited exposure data for risk assessment exists so far due to the lack of suitable analytical methods. Nanoplastic detection in food poses a great analytical challenge due to the complexity of plastics and food matrices as well as the small size and expectedly low concentration of the plastic particles. Multidetector field flow fractionation has emerged as a valuable analytical technique for nanoparticle separation over the last decades, and the first studies using the technique for analyzing nanoplastics in complex matrices are emerging. In combination with online detectors and offline analysis, multidetector field flow fractionation is a powerful platform for advanced characterization of nanoplastics in food by reducing sample complexity, which otherwise hampers the full potential of most analytical techniques. The focus of this article is to present the current state of the art of multidetector field flow fractionation for nanoplastic analysis and to discuss future trends and needs aiming at the analysis of nanoplastics in food.

One-pot co-extraction of dispersive solid phase extraction employing iron-tannic nanoparticles assisted cloud point extraction for the determination of tetracyclines by high-performance liquid chromatography.

Iron-tannic nanoparticles were used as a new adsorbent for dispersive solid phase extraction (DSPE) synergized with cloud point extraction (CPE) to enrich four tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) prior to high-performance liquid chromatographic determination. DSPE and CPE were performed simultaneously in a one-pot co-extraction to form iron-tannic nanoparticles in-situ and pre-concentrate the tetracyclines. The parameters affecting the extraction efficiency were investigated. Using the optimal parameters, linear calibrations ranging from 2.63 to 1000 ng mL-1 were obtained, with determination coefficients greater than 0.996. The limit of detection was found to be 1.06-3.19 ng mL-1, while the limit of quantification was 2.63-10.65 ng mL-1. Precision was expressed as a relative standard deviation of less than 10%. The residues of the four tetracyclines in milk, eggs, honey, chicken liver, and chicken kidney samples were determined by the proposed method. The recoveries ranged from 79.3 to 107.1%. The results indicated that the proposed method was an alternative method for the extraction and pre-concentration of tetracyclines with high extraction and enrichment efficiency. In addition, it promoted rapidity and environmental friendliness.

Simultaneous Sizing and Refractive Index Analysis of Heterogeneous Nanoparticle Suspensions.

Rapid and reliable characterization of heterogeneous nanoparticle suspensions is a key technology across the nanosciences. Although approaches exist for homogeneous samples, they are often unsuitable for polydisperse suspensions, as particles of different sizes and compositions can lead to indistinguishable signals at the detector. Here, we introduce holographic nanoparticle tracking analysis, holoNTA, as a straightforward methodology that decouples size and material refractive index contributions. HoloNTA is applicable to any heterogeneous nanoparticle sample and has the sensitivity to measure the intrinsic heterogeneity of the sample. Specifically, we combined high dynamic range k-space imaging with holographic 3D single-particle tracking. This strategy enables long-term tracking by extending the imaging volume and delivers precise and accurate estimates of both scattering amplitude and diffusion coefficient of individual nanoparticles, from which particle refractive index and hydrodynamic size are determined. We specifically demonstrate, by simulations and experiments, that irrespective of localization uncertainty and size, the sizing sensitivity is improved as our extended detection volume yields considerably longer particle trajectories than previously reported by comparable technologies. As validation, we measured both homogeneous and heterogeneous suspensions of nanoparticles in the 40-250 nm size range and further monitored protein corona formation, where we identified subtle differences between the nanoparticle-protein complexes derived from avidin, bovine serum albumin, and streptavidin. We foresee that our approach will find many applications of both fundamental and applied nature where routine quantification and sizing of nanoparticles are required.

Investigation on formulation parameters of donepezil HCl loaded solid lipid nanoparticles

Abstract Donepezil-HCl is a member of the acetylcholinesterase inhibitors that is indicated for the symptomatic treatment of Alzheimer's disease (AD) and has many side effects. In this study, to reduce the side effects of Donepezil-HCl and increase the penetration of the drug through the blood-brain barrier, we aimed to design a solid lipid nanoparticle (SLN) formulation. The effects of the different formulation parameters, such as homogenization speed, sonication time, lipid and drug concentration, surfactant type and concentration, and volume of the aqueous phase, were assessed for optimization. The particle size and PDI increased with increasing lipid concentration but decreased with increasing amounts of surfactant (Tween 80) and co-surfactant (lecithin). When the homogenization rate and sonication time increased, the particle size decreased and the encapsulation efficiency increased. The optimized formulation exhibited particle size, PDI, encapsulation efficiency, and zeta potential of 87.2±0.11 nm; 0.22±0.02; 93.84±0.01 %; -17.0±0.12 mV respectively. The in vitro release investigation revealed that approximately 70% of Donepezil-HCl was cumulatively released after 24 hours. TEM analysis proved that spherical and smooth particles were obtained and formulations had no toxic effect on cells. The final optimized formulation could be a candidate for Donepezil-HCl application in Alzheimer's treatment with reduced side effects and doses for patients

Trophic transfer of nanoplastics through a microalgae-crustacean-small yellow croaker food chain: Inhibition of digestive enzyme activity in fish.

This study investigated the effects of nanoplastics on marine organisms via trophic transfer in the food chain. We designed a three-step food chain comprising microalga (Dunaliella salina), small crustaceans (Artemia franciscana), and fish (small yellow croakers; Larimichthys polyactis) and evaluated the effects of trophic transfer in marine organisms, as well as verified the possibility of nanoplastic transfer to humans via trophic transfer. Using amine-modified nanopolystyrene (nPS-NH2) as a pollutant, we conducted both direct-exposure and trophic transfer experiments to determine how pollutants move through the food chain (D. salina → A. franciscana). Exposure of D. salina to nPS-NH2, which was adsorbed on its cell wall, resulted in transfer to A. franciscana with alteration of gut permeability. Additionally, assessment of the adverse effects of nPS-NH2 via a dietary pathway (three-step food chain) on the L. polyactis digestive system revealed that nanoplastics adsorbed to the cell wall of microalgae are gradually transferred to higher trophic level organisms, such as via food resources consumed by humans, inducing the inhibition of digestive enzyme activity (α-amylase). It indicates that human could eventually be exposed to nanoplastics and experience toxicity.

Nanoparticle Tracking in Single-Antiresonant-Element Fiber for High-Precision Size Distribution Analysis of Mono- and Polydisperse Samples.

Accurate determination of the size distribution of nanoparticle ensembles remains a challenge in nanotechnology-related applications due to the limitations of established methods. Here, a microstructured fiber-assisted nanoparticle tracking analysis (FaNTA) realization is introduced that breaks existing limitations through the recording of exceptionally long trajectories of rapidly diffusing polydisperse nanoparticles, resulting in excellent sizing precision and unprecedented separation capabilities of bimodal nanoparticle mixtures. An effective-single-mode antiresonant-element fiber allows to efficiently confine nanoparticles in a light-guiding microchannel and individually track them over more than 1000 frames, while aberration-free imaging is experimentally confirmed by cross-correlation analysis. Unique features of the approach are (i) the highly precise determination of the size distribution of monodisperse nanoparticle ensembles (only 7% coefficient of variation) and (ii) the accurate characterization of individual components in a bimodal mixture with very close mean diameters, both experimentally demonstrated for polymer nanospheres. The outstanding performance of the FaNTA realization can be quantified by introducing a new model for the bimodal separation index. Since FaNTA is applicable to all types of nano-objects down to sub-20 nm diameters, the method will improve the precision standard of mono- and polydisperse nanoparticle samples such as nano-plastics or extracellular vesicles.

α-Fe2O3 nanoparticles and hazardous air pollutants release during cooking using cast iron wok in a commercial Chinese restaurant.

Long-term exposure to fine particles (PM2.5), ultrafine particles (UFPs), and volatile organic compounds (VOCs) emissions from cooking has been linked to adverse human health effects. Here, we measured the real-time number size distribution of particles emitted when cooking two served food in Chinese restaurants and estimated the emission rate of UFPs and PM2.5. Experiments were conducted under a control hood, and both online measurement and offline analysis of PM2.5 were carried out. The measured emission rates of PM2.5 generated from deep-frying and grilling were 0.68 ± 0.11 mg/min and 1.58 ± 0.25 mg/min, respectively. Moreover, the UFPs emission rate of deep-frying (4.3 × 109 #/min) is three times higher than that of grilling (1.4 × 109 #/min). Additionally, the PM2.5 emission of deep-frying was comprised of a considerable amount of α-Fe2O3 (5.7% of PM2.5 total mass), which is more toxic than other iron oxide species. A total of six carcinogenic HAPs were detected, among which formaldehyde, acrolein, and acetaldehyde were found to exceed the inhalation reference concentration (RfC) for both cooking methods. These findings can contribute to future evaluation of single particle and HAPs emission from cooking to better support toxicity assessment.

Rapid Sample Screening Method for Authenticity Controlling of Vanilla Flavours Using Liquid Chromatography with Electrochemical Detection Using Aluminium-Doped Zirconia Nanoparticles-Modified Electrode.

A rapid and sensitive technique for frauds determination in vanilla flavors was developed. The method comprises separation by liquid chromatography followed by an electrochemical detection using a homemade screen-printed carbon electrode modified with aluminium-doped zirconia nanoparticles (Al-ZrO2-NPs/SPCE). The prepared nanomaterials (Al-ZrO2-NPs) were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). This method allows for the determination of six phenolic compounds of vanilla flavors, namely, vanillin, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, vanillyl alcohol, vanillic acid and ethyl vanillin in a linear range between 0.5 and 25 µg g-1, with relative standard deviation values from 2.89 to 4.76%. Meanwhile, the limits of detection and quantification were in the range of 0.10 to 0.14 µg g-1 and 0.33 to 0.48 µg g-1, respectively. In addition, the Al-ZrO2-NPs/SPCE method displayed a good reproducibility, high sensitivity, and good selectivity towards the determination of the vanilla phenolic compounds, making it suitable for the determination of vanilla phenolic compounds in vanilla real extracts products.

A Quantitative Method for Determining Uptake of Silica Nanoparticles in Macrophages by Single Particle Inductively Coupled Plasma-Mass Spectrometry.

Engineered nanomaterials are becoming increasingly ubiquitous in our society, with numerous applications in medicine, consumer products, bioremediation, and advanced materials. As these nanomaterials increase in variety, analyzing their characteristics is of great importance. Single particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) is a high-throughput, sensitive, and robust instrumental analysis method used to simultaneously characterize and quantify nanoparticles in a variety of matrices. One such type of nanoparticle of interest is amorphous silica nanoparticles (SiNPs). SiNPs have widespread use in consumer products such as food and cosmetics and are prime candidates for novel medical applications and uses in environmental bioremediation. Despite their increased use, SiNPs have been shown to have toxicological properties in vitro and in vivo, particularly with regard to the immune system. Because of the potential for increased SiNP exposure in the general public and in occupational settings, examining the relationship that SiNPs have with immune cells such as macrophages to elucidate mechanisms of toxicity is vital. To effectively determine the toxicity of nanoparticles, it is critical to examine dosimetry and the amount of nanoparticles taken up by the cell of interest. Different cell types have different uptake profiles, and varying physicochemical properties govern nanoparticle dosimetry and uptake in cells. Here, we describe a protocol using SP-ICP-MS to quantify and characterize the size, size distribution, and amount of SiNPs present in a cell and medium sample. We use a single-step digestion, which allows for the digestion of biological matrices while simultaneously keeping the SiNPs intact for SP-ICP-MS analysis. Clinically, this approach has the potential to be used as a method for analyzing SiNPs in other biological matrices, potentially as a way of defining SiNP uptake as a biomarker in immune-mediated diseases. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Treatment of cells with silica nanoparticles (SiNPs) and digestion of biological matrices Support Protocol 1: Culturing RAW 264.7 cells for SiNP uptake assay Support Protocol 2: Determination of SiNP size via dynamic light scattering Support Protocol 3: Optimization of sample and ICP-MS parameters for SP-ICP-MS analysis of cells and medium Basic Protocol 2: Analysis and quantification of SiNP uptake in macrophages with SP-ICP-MS.

Lotus-like Ni@NiO nanoparticles embedded porous carbon derived from MOF-74/cellulose nanocrystal hybrids as solid phase microextraction coating for ultrasensitive determination of chlorobenzenes from water.

Lotus-like Ni@NiO embedded porous carbons (Ni@NiO/PCs) were fabricated by pyrolysis of MOF-74/cellulose nanocrystal hybrids, and used as a solid phase microextraction (SPME) coating for ultrasensitive determination of chlorobenzenes (CBs) from water combined with gas chromatography-mass spectrometry. Owing to its abundant chemical groups, high porosity, and excellent thermal stability, the as-prepared Ni@NiO/PCs presented superior extraction performance compared to commercial SPME coatings. Notably, Ni@NiO/PCs derived from MOF-74/CNC hybrids presented higher extraction efficiencies towards CBs than that derived from pristine CNC and MOF-74 due to the formation of micro/mesopores and more abundant oxygen-containing groups. Under the optimum extraction conditions, the proposed analytical method presented wide linearity range (0.5-1500 ng L-1), ultra-low detection of limit (0.005-0.049 ng L-1), and excellent precision with relative standard deviations of 4.7-9.2% for a single fiber and 8.8-10.9% for 5 fibers, and long lifetime (≥160 times). The proposed analytical method was finally applied for determination of CBs from real water samples, and the recoveries were in the range of 93.2-116.8% towards eight CBs. This study delivered a novel and efficient sorbent as SPME coating to extraction and determination of CBs from water.

Quantitative analysis of polymer-grafted cellulose nanocrystals using a ssNMR method on the basis of cross polarization reciprocity relation.

The quantitative analysis of surface modified CNCs is an essential issue for the research and development of the relating materials. Herein, an improved quantitative ssNMR method of rQCPZRC was employed for analyzing CNCs materials. Firstly, CNCs and three PMMA/CNCs mixtures were chosen to evaluate the performance of rQCPZRC method. It was demonstrated that rQCPZRC method is capable to quantify the carbon ratios of CNCs and the components contents of CNCs/PMMA mixtures, with percentage errors on the order of 4%. Furthermore, rQCPZRC method was employed determining the surface grafting proportion of three CNCs-g-PMMA samples. The measured results showed high precision with RSD of 2.1%. Moreover, the experimental time of rQCPZRC was 5.5 h for each sample, notably shorter than the traditional ssNMR method of 146-498 h. Thus, our work recommends rQCPZRC as a tool for quantitative analysis of CNCs and their relating materials.

Fast and non-destructive neutron activation analysis for simultaneous determination of TiO2 and SiO2 in sunscreens with attention to regulatory and research issues.

A new instrumental neutron activation analysis (INAA) for the simultaneous determination of titanium (TiO2) and silica (SiO2) dioxide as UV-filters in sunscreens is described. Samples are encapsulated, neutron irradiated (30 s) and after a suitable decay (3 min), the induced 51Ti (T1/2 = 5.76 min) and 29Al (T1/2 = 6.56 min) radionuclides are measured for the emitted γ-ray fingerprint. Three applications were carried out: (i) screening study (analysis of commercial sunscreens in combination with single particle inductively coupled plasma mass spectrometry (sp-ICP-MS); (ii) research study (development of innovative UV-filters such as titanium dioxide or bismuth titanate loaded inorganic mesoporous silica nanoparticles, MSN); (iii) validation study (intercalibration of a spectrochemical method - inductively coupled plasma optical emission spectrometry, ICP-OES). Collectively, the nuclear method appears a powerful tool adequate for quantifying TiO2 and SiO2 in the above studies. The limited accessibility at the nuclear reactor for neutron activation is probably one of the reasons why the excellent characteristics of the nuclear technique are not always fully known and exploited in the industrial and research chemical world.

Single-particle inductively coupled plasma mass spectrometry using ammonia reaction gas as a reliable and free-interference determination of metallic nanoparticles.

Intensive production of nanomaterials, especially metallic nanoparticles (MNPs), and their release into the environment pose several risks for humans and ecosystem health. Consequently, high-efficiency analytical methodologies are required for control and characterization of these emerging pollutants. Single-particle inductively coupled plasma - mass spectrometry (SP-ICP-MS) is a promising technique which allows the determination and characterization of MNPs. However, several elements or isotopes are hampered by spectral interferences, and dynamic-reaction cell (DRC) technology is becoming a useful tool for free interference determination by ICP-MS. DRC-based SP-ICP-MS methods using ammonia as a reaction gas (either on-mass approach or mass-shift approaches) have been developed for determining titanium dioxide nanoparticles (TiO2 NPs), copper oxide nanoparticles (CuO NPs), copper nanoparticles (Cu NPs), and zinc oxide nanoparticles (ZnO NPs). The effects of parameters such as ammonia flow rate and dwell time on the peak width (NP transient signal in SP-ICP-MS) were comprehensively studied. Influence of NP size and nature were also investigated.

Photonic Crystal Effects on Upconversion Enhancement of LiErF4:0.5%Tm3+@LiYF4 for Noncontact Cholesterol Detection.

Cholesterol is a vital compound in maintenance for human health, and its concentration levels are tightly associated with various diseases. Therefore, accurate monitoring of cholesterol is of great significance in clinical diagnosis. Herein, we fabricated a noncontact biosensor based on photonic crystal-enhanced upconversion nanoparticles (UCNPs) for highly sensitive and interference-free cholesterol detection. By compounding LiErF4:0.5%Tm3+@LiYF4 UCNPs with poly(methyl methacrylate) (PMMA) photonic crystals (OPCs), we were able to selectively tune the coupling of the photonic band gap to the excitation field and modulate the upconversion (UC) luminescence intensity, given the unique multi-wavelength excitation property of LiErF4:0.5%Tm3+@LiYF4. A 48.5-fold enhancement of the monochromatic red UC emission was ultimately achieved at 980 nm excitation, ensuring improved detection sensitivity. Based on the principle of quenching of the intense monochromic red UC emission by the oxidation products of 3,3',5,5'-tetramethylbenzidine (TMB) yielded from the cholesterol cascade reactions, the biosensor has a detection limit of 1.6 µM for cholesterol with excellent specificity and stability. In addition, the testing results of the as-designed biosensor in patients are highly consistent with clinical diagnostic data, providing a sensitive, reliable, reusable, interference-free, and alternative strategy for clinical cholesterol detection.