Recent developments in nanoparticle-based MALDI mass spectrometric analysis of phosphoproteomes

Mass spectrometry-based strategies are widely used for mapping of post-translational modifications of phosphoproteins. However, the presence of large amounts of non-phosphopeptides seriously interferes by suppressing the intensities of signals for phosphopeptides in direct MALDI-MS techniques due to the low stoichiometry of protein phosphorylation. Several MALDI-MS approaches are known which use either nanoparticles (NPs) as affinity probes, or NPs as microwave heat absorbers. They assist in the enrichment of trace levels of phosphopeptides from complex protein digests and require minimal sample pretreatment, digestion times, and sample volume. This leads to enhance sensitivity and selectivity in the analysis of the phosphoproteomes. This review (with 89 refs.) summarizes and discusses recent developments in the field, with a particular focus on the potential use of nanomaterials such as metal oxides, metal NPs, NPs-coated target plates, and as core-shell nanocomposites acting as affinity probes and as heat absorbers in MALDI-MS analysis of phosphoproteomes.

Nanosorbents as Materials for Extraction Processes of Environmental Contaminants and Others

The aim of this work focuses on the application of nanomaterials (NMs) in different sorptive extraction techniques for the analysis of organic contaminants from environmental samples of distinct matrix compositions. Without any doubt, the integration of specific NMs such as carbonaceous nanomaterials, magnetic nanoparticles (MNPs), metal–organic frameworks (MOFs), silica nanoparticles, and ion-imprinted NPs with solid-phase extraction techniques counting d-SPE, solid-phase microextraction (SPME), and stir bar sorptive extraction (SBSE) impact on the improvements in analytical performance. The application of NMs as sorbents in the extraction of organic pollutants in environmental samples allows for providing better sensitivity, repeatability, reproducibility, and reusability.     

Biogenic Sulfur-Based Chalcogenide Nanocrystals: Methods of Fabrication,Mechanistic Aspects,and Bio-Applications

Bio-nanotechnology has emerged as an efficient and competitive methodology for the production of added-value nanomaterials (NMs). This review article gathers knowledge gleaned from the literature regarding the biosynthesis of sulfur-based chalcogenide nanoparticles (S-NPs), such as CdS, ZnS and PbS NPs, using various biological resources, namely bacteria, fungi including yeast, algae, plant extracts, single biomolecules, and viruses. In addition, this work sheds light onto the hypothetical mechanistic aspects, and discusses the impact of varying the experimental parameters, such as the employed bio-entity, time, pH, and biomass concentration, on the obtained S-NPs and, consequently, on their properties. Furthermore, various bio-applications of these NMs are described. Finally, key elements regarding the whole process are summed up and some hints are provided to overcome encountered bottlenecks towards the improved and scalable production of biogenic S-NPs.     

Trends in the sample preparation and analysis of nanomaterials as environmental contaminants

Much research on the use of nanomaterials in different applications is being conducted in areas such as water treatment, catalysis, oil processing, medicine, food, sensors, energy storage, building materials, constructions, and others. Nanoparticles are ultra-small particles with exceptional properties, but some nanoparticles and nanomaterials may exhibit harmful properties when leaked into the environment. Due to the lack of analytical methods for the detection and analysis of nanoparticles in complex matrices, not much is known about the potential risks associated with nanomaterials. Therefore, more knowledge is needed of the sampling and analysis of nanomaterials (NMs) as environmental contaminants. This review is undertaken to identify and assess key characteristics in potential sampling and analysis methods for identifying and quantifying the occurrence of NMs in numerous types of environmental media. To select suitable sampling and analysis methods, information on NM sources and transformation in environmental media is essential and thus is also discussed. This provides more information about the negative impacts of NMs on the environment. Challenges and future perspectives on the determination of NMs are also discussed.     

Quantifying the dissolution of nanomaterials at the nano-bio interface

With the rapid development of nanoscience and nanotechnology, more engineered nanomaterials(NMs) are being released into the environment. Such releases might lead to unwanted exposure. The dissolution of NMs at nano-bio interfaces is one of the most noteworthy causes of the toxicity of dissolvable NMs. A growing number of studies are focusing assessing NMs dissolution during exposure tests. This mini review considers recent developments in the quantitative tools for the assessment of NMs dissolution, and highlights the critical points in the evaluation of the toxicity of dissolvable NMs.     

Trends in nanomaterial-based solid-phase microextraction with a focus on environmental applications - A review

Effective solid-phase microextraction (SPME) in environmental field represents a crucial step for the adequate extraction of several analytes. Several materials have been traditionally developed for SPME of several analytes from environmental samples, even though their several restrictions such as post-treatment required, elevate costs and limited efficiency. Recently, nanomaterials (NMs) have emerged as a promising substitute for SPME in environmental applications of traditional techniques, due to their small size and their high specific surface-area which enhances their high reactivity. In this present review different NMs which have recently been utilized as SPME sorbent for environmental applications are classified into eleven main groups, namely nanoparticles, nanofibers, nanoflakes, nanocomposites, nanorods, nanotubes, nanohorns, nanosheets, nanocubes, nanospheres and polymer-based NMs. Application of these NMs in SPME modes and configurations for environmental analysis has been reviewed. The study discusses not only the advantages but also the major limitations of using such NMs.     

Analytical chemistry of metallic nanoparticles in natural environments

The use of metallic nanoparticles (NPs) has exponentially increased in the past decade due to their unique physical and chemical properties at nano-scales [1]. They are added to a myriad of materials and compositions. The key question is not if NPs will enter environmental compartments but rather when. The fate and the stability of NPs in the environment play important roles in determining their environmental distributions and probably control the risk to human health through exposure. Emissions of nanomaterials (NMs) could be intentional or unintentional but occur in particulate, aggregate or embedded states.Despite environmental transformations and changes in their surrounding environment, metallic NPs (M-NPs) tend to exist as stable colloidal aggregates or dispersions. Characterizing NPs and NMs in environmental samples implies determination of their size, their chemical composition and their bulk concentrations in the matrix. Differential size filtration is the most commonly used method to isolate NPs from aqueous matrices. Micro-filtration, nano-filtration, cross-flow filtration, and ultracentrifugation are usually employed to achieve the highest degree of segregation.Chemical characterization of NPs and NMs has traditionally been done using transmission/scanning electron microscopy (TEM/SEM) followed by energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). However, because of their intrinsic limitations, methods have also been combined and validated [e.g., size exclusion and ion chromatography (SEC and IC) with multi-element detection {inductively-coupled plasma mass spectrometry and optical emission spectroscopy (ICP-MS and ICP-OES)].This review describes the current state and the challenges of isolating, segregating and detecting M-NPs in environmental samples. A simple case study shows a common procedure for the analysis of NPs in complex aqueous matrices.     

Benchmarking the ACEnano Toolbox for Characterisation of Nanoparticle Size and Concentration by Interlaboratory Comparisons

ACEnano is an EU-funded project which aims at developing, optimising and validating methods for the detection and characterisation of nanomaterials (NMs) in increasingly complex matrices to improve confidence in the results and support their use in regulation. Within this project, several interlaboratory comparisons (ILCs) for the determination of particle size and concentration have been organised to benchmark existing analytical methods. In this paper the results of a number of these ILCs for the characterisation of NMs are presented and discussed. The results of the analyses of pristine well-defined particles such as 60 nm Au NMs in a simple aqueous suspension showed that laboratories are well capable of determining the sizes of these particles. The analysis of particles in complex matrices or formulations such as consumer products resulted in larger variations in particle sizes within technologies and clear differences in capability between techniques. Sunscreen lotion sample analysis by laboratories using spICP-MS and TEM/SEM identified and confirmed the TiO₂ particles as being nanoscale and compliant with the EU definition of an NM for regulatory purposes. In a toothpaste sample orthogonal results by PTA, spICP-MS and TEM/SEM agreed and stated the TiO₂ particles as not fitting the EU definition of an NM. In general, from the results of these ILCs we conclude that laboratories are well capable of determining particle sizes of NM, even in fairly complex formulations.     

Gold Nanomaterials: Preparation,Chemical Modification,Biomedical Applications and Potential Risk Assessment

Gold nanomaterials (Au NMs) have attracted increasing attention in biomedicine due to their facile preparation, multifunctional modifications, unique optical and electrical properties, and good biocompatibility. The physicochemical properties of Au NMs at nanoscale, like size, shape, surface chemistry, and near field effects, are rendering Au NMs potent candidates in biomedicine. Thus, risk assessment of negative effects of Au NMs on biological systems is becoming urgent and necessary for future applications. In this review, we summarize up-to-date progresses on the preparation and modification of Au NMs and their biomedical applications, including biosensor, bioimaging and phototherapy, gene/drug delivery. Finally, we discuss the potential risk of Au NMs to biological systems, which is instructive for rationally designing and preparing nanomaterials for safe applications in nanomedicine.     

Evaluation criteria for the quality of published experimental data on nanomaterials and their usefulness for QSAR modelling

Nowadays nanotechnology is one of the most promising areas of science. The number and quantity of synthesized nanomaterials increase exponentially, therefore it is reasonable to expect that comprehensive risk assessment based only on empirical testing of all novel engineered nanoparticles (NPs) will very soon become impossible. Hence, the development of computational methods complementary to experimentation is very important. Quantitative structure-property relationship (QSPR) and quantitative structure-activity relationship (QSAR) models widely used in pharmaceutical chemistry and environmental science can also be modified and adopted for nanotechnology to predict physico-chemical properties and toxicity of empirically untested nanomaterials. All QSPR/QSAR modelling activities are based on experimentally derived data. It is important that, within a given data set, all values should be consistent, of high quality and measured according to a standardized protocol. Unfortunately, the amount of such data available for engineered nanoparticles in various data sources (i.e. databases and the literature) is very limited and seldom measured with a standardized protocol. Therefore, we have proposed a framework for collecting and evaluating the existing data, with the focus on possible applications for computational evaluation of properties and biological activities of nanomaterials.     

Ecotoxicity and analysis of nanomaterials in the aquatic environment

Nanotechnology is a major innovative scientific and economic growth area. However nanomaterial residues may have a detrimental effect on human health and the environment. To date there is a lack of quantitative ecotoxicity data, and recently there has been great scientific concern about the possible adverse effects that may be associated with manufactured nanomaterials. Nanomaterials are in the 1- to 100-nm size range and can be composed of many different base materials (carbon, silicon and metals, such as gold, cadmium and selenium) and they have different shapes. Particles in the nanometer size range do occur both in nature and as a result of existing industrial processes. Nevertheless, new engineered nanomaterials and nanostructures are different because they are being fabricated from the “bottom up”. Nanomaterial properties differ compared with those of the parent compounds because about 40–50% of the atoms in nanoparticles (NPs) are on the surface, resulting in greater reactivity than bulk materials. Therefore, it is expected that NPs will have different biological effects than parent compounds. In addition, release of manufactured NPs into the aquatic environment is largely an unknown. The surface properties and the very small size of NPs and nanotubes provide surfaces that may bind and transport toxic chemical pollutants, as well as possibly being toxic in their own right by generating reactive radicals. This review addresses hazards associated and ecotoxicological data on nanomaterials in the aquatic environment. Main weaknesses in ecotoxicological approaches, controversies and future needs are discussed. A brief discussion on the scarce number of analytical methods available to determinate nanomaterials in environmental samples is included.     

Nanomaterials and lab-on-a-chip technologies

Lab-on-a-chip (LOC) platforms have become important tools for sample analysis and treatment with interest for DNA, protein and cells studies or diagnostics due to benefits such as the reduced sample volume, low cost, portability and the possibility to build new analytical devices or be integrated into conventional ones. These platforms have advantages of a wide set of nanomaterials (NM) (i.e. nanoparticles, quantum dots, nanowires, graphene etc.) and offer excellent improvement in properties for many applications (i.e. detectors sensitivity enhancement, biolabelling capability along with other in-chip applications related to the specificities of the variety of nanomaterials with optical, electrical and/or mechanical properties). This review covers the last trends in the use of nanomaterials in microfluidic systems and the related advantages in analytical and bioanalytical applications. In addition to the applications of nanomaterials in LOCs, we also discuss the employment of such devices for the production and characterization of nanomaterials. Both framed platforms, NMs based LOCs and LOCs for NMs production and characterization, represent promising alternatives to generate new nanotechnology tools for point-of-care diagnostics, drug delivery and nanotoxicology applications.     

Toxicity of nanomaterials

Nanoscience has matured significantly during the last decade as it has transitioned from bench top science to applied technology. Presently, nanomaterials are used in a wide variety of commercial products such as electronic components, sports equipment, sun creams and biomedical applications. There are few studies of the long-term consequences of nanoparticles on human health, but governmental agencies, including the United States National Institute for Occupational Safety and Health and Japan's Ministry of Health, have recently raised the question of whether seemingly innocuous materials such as carbon-based nanotubes should be treated with the same caution afforded known carcinogens such as asbestos. Since nanomaterials are increasing a part of everyday consumer products, manufacturing processes, and medical products, it is imperative that both workers and end-users be protected from inhalation of potentially toxic NPs. It also suggests that NPs may need to be sequestered into products so that the NPs are not released into the atmosphere during the product's life or during recycling. Further, non-inhalation routes of NP absorption, including dermal and medical injectables, must be studied in order to understand possible toxic effects. Fewer studies to date have addressed whether the body can eventually eliminate nanomaterials to prevent particle build-up in tissues or organs. This critical review discusses the biophysicochemical properties of various nanomaterials with emphasis on currently available toxicology data and methodologies for evaluating nanoparticle toxicity (286 references).     

Impact of nanomaterials on high-throughput separation methodologies

Due to the unique properties, such as their large surface to volume ratio and easy modification, nanomaterials have recently been studied as effective sorbents in the field of separation science. It has proven to be more effective and efficient to use nanoparticles (NPs) as a stationary phase in solid-phase extraction separation. In addition, NPs can be also used as buffer additives in capillary electrophoresis separation. This review highlights recent developments in high-throughput separation methodologies employing nanomaterials such as carbon nanotubes, gold nanoparticles and magnetic NPs etc.     

Targeted polymeric therapeutic nanoparticles: design, development and clinical translation

Polymeric materials have been used in a range of pharmaceutical and biotechnology products for more than 40 years. These materials have evolved from their earlier use as biodegradable products such as resorbable sutures, orthopaedic implants, macroscale and microscale drug delivery systems such as microparticles and wafers used as controlled drug release depots, to multifunctional nanoparticles (NPs) capable of targeting, and controlled release of therapeutic and diagnostic agents. These newer generations of targeted and controlled release polymeric NPs are now engineered to navigate the complex in vivo environment, and incorporate functionalities for achieving target specificity, control of drug concentration and exposure kinetics at the tissue, cell, and subcellular levels. Indeed this optimization of drug pharmacology as aided by careful design of multifunctional NPs can lead to improved drug safety and efficacy, and may be complimentary to drug enhancements that are traditionally achieved by medicinal chemistry. In this regard, polymeric NPs have the potential to result in a highly differentiated new class of therapeutics, distinct from the original active drugs used in their composition, and distinct from first generation NPs that largely facilitated drug formulation. A greater flexibility in the design of drug molecules themselves may also be facilitated following their incorporation into NPs, as drug properties (solubility, metabolism, plasma binding, biodistribution, target tissue accumulation) will no longer be constrained to the same extent by drug chemical composition, but also become in-part the function of the physicochemical properties of the NP. The combination of optimally designed drugs with optimally engineered polymeric NPs opens up the possibility of improved clinical outcomes that may not be achievable with the administration of drugs in their conventional form. In this critical review, we aim to provide insights into the design and development of targeted polymeric NPs and to highlight the challenges associated with the engineering of this novel class of therapeutics, including considerations of NP design optimization, development and biophysicochemical properties. Additionally, we highlight some recent examples from the literature, which demonstrate current trends and novel concepts in both the design and utility of targeted polymeric NPs (444 references).     

Nanomaterials of high surface energy with exceptional properties in catalysis and energy storage

The properties of nanomaterials for use in catalytic and energy storage applications strongly depends on the nature of their surfaces. Nanocrystals with high surface energy have an open surface structure and possess a high density of low-coordinated step and kink atoms. Possession of such features can lead to exceptional catalytic properties. The current barrier for widespread industrial use is found in the difficulty to synthesise nanocrystals with high-energy surfaces. In this critical review we present a review of the progress made for producing shape-controlled synthesis of nanomaterials of high surface energy using electrochemical and wet chemistry techniques. Important nanomaterials such as nanocrystal catalysts based on Pt, Pd, Au and Fe, metal oxides TiO(2) and SnO(2), as well as lithium Mn-rich metal oxides are covered. Emphasis of current applications in electrocatalysis, photocatalysis, gas sensor and lithium ion batteries are extensively discussed. Finally, a future synopsis about emerging applications is given (139 references).     

Preparation of Photocatalytic Au–Ag2Te Nanomaterials

A facile approach has been developed for the preparation of various morphologies of Au–Ag₂Te nanomaterials (NMs) that exhibit strong photocatalytic activity. Te NMs (nanowires, nanopencils, and nanorice) were prepared from TeO₂ in the presence of various concentrations (16, 8, and 4 M ) of a reducing agent (N₂H₄) at different temperatures (25 and 60 °C). These three Te NMs were then used to prepare Au–Ag₂Te NMs by spontaneous redox reactions with Au³⁺ and Ag⁺ ions sequentially. The Au–Ag₂Te nanopencils exhibit the highest activity toward degradation of methylene blue and formation of active hydroxyl radicals on solar irradiation, mainly because they absorb light in the visible region most strongly. All three differently shaped Au–Ag₂Te NMs (10 μg mL^?1) provide a death rate of Escherichia coli greater than 80 % within 60 min, which is higher than that of 51 % for commercial TiO₂ nanoparticles (100 μg mL^?1). Under light irradiation, the Au NPs in Au–Ag₂Te NMs enhance the overall photo‐oxidation ability of Ag₂Te NMs through faster charge separation because of good contact between Ag₂Te and Au segments. With high antibacterial activity and low toxicity toward normal cells, the Au–Ag₂Te NMs hold great potential for use as efficient antibacterial agents.     

Nanomaterials in Protein Sample Preparation

Protein sample preparation is the most critical step in protein analysis of complex samples and is constituted by tedious, time-consuming, and difficult-to-automate steps that usually involve the use of high volumes of solvents. In recent years, novel extraction or digestion nanomaterials (NMs) have been developed aiming to overcome these drawbacks. In this review, we have grouped the recent works related to the development of new NMs and their applications to the extraction, enrichment/purification, and digestion of proteins. This paper evaluates the role of different kinds of NMs in each step of protein sample preparation focusing on the type of established interaction between the protein and the nanomaterial, their sensitivity and selectivity, their adsorption capacity, and the advantages that they bring in relation to time, efficiency, or reusability.