Optimisation, evaluation and application of asymmetrical flow field-flow fractionation with single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) to characterise silver nanoparticles in environmental media

Biomedical Evaluation of Biosynthesized Silver Nanoparticles by Jasminum Sambac (L.) Aiton Against Breast Cancer Cell Line, and Both Bacterial Strains Colonies

The biosynthesis of silver nanoparticles (AgNPs) was conducted using the Iraqi Jasminum sambac (L.) Aiton leaves having substantial bioreduction and capping properties. The aqueous extract has been characterized using FTIR to observe changes in functional groups of extract compared to extract-AgNPs. GC-MS understands the mechanism synthesis of AgNPs based on the aqueous extract of J. sambac through identification of aqueous extracted. The synthesized AgNPs were characterized using UV–Vis at 455[Formula: see text]nm, XRD broad chart owing to size of AgNPs and TEM (AgNPs average size less than 10[Formula: see text]nm). FESEM-EDX was carried out to observe the nearly spherical shape with elemental composition. DLS was appointed with hydrodynamic radius as 105.9[Formula: see text]nm and also had a good polydispersity at 0.357, and [Formula: see text]-potential at [Formula: see text]23.1. AgNPs have antibacterial gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli), cytotoxicity MTT assay against breast cancer MCF-7 cell line IC50 at 222.6[Formula: see text][Formula: see text]g/mL, genotoxicity fragmented DNA of MCF-7 by comet assay, emphasized apoptosis cells through cell cycle flow cytometry. Overall, safe, cost-effective, and scalable biogenic nano-formulation of Jasminum sambac-AgNPs possesses antibacterial and anticancer therapeutic applications.

Discrimination and Quantification of Soil Nanoparticles by Dual-Analyte Single Particle ICP-QMS

This study presents the new application of dual-analyte single particle inductively coupled plasma quadrupole mass spectrometry (spICP-QMS) to the discrimination and quantification of two typical soil nanoparticles (kaolinite and goethite nanoparticles, abbr. KNPs and GNPs) in three samples (SA, SB, and SC) with three detection events (Al unpaired event, Fe unpaired event, and paired event). SA was mainly composed of KNPs with a concentration of 28 443 ± 817 particle mL^-1 and a mean particle size of 140.7 ± 0.2 nm. SB was mainly composed of GNPs with a concentration of 39 283 ± 702 particle mL^-1 and a mean particle size of 141.8 ± 2.9. In SC, the concentrations of KNPs and GNPs were 22 4541 ± 1401 and 70 604 ± 1623 particle mL^-1, respectively, and the mean particle sizes of KNPs and GNPs were 140.7 ± 0.2 and 60.2 ± 0.3 nm, respectively. The accuracy of dual-analyte spICP-QMS was determined by spiking experiments, comparing these results with the measurements of other techniques, analyzing the samples in different SA and SB proportions and in different SC concentrations. Our results demonstrated that the dual-analyte spICP-QMS is a promising approach to distinguishing different kinds of natural NPs in soils.

Minimizing the Silver Free Ion Content in Starch Coated Silver Nanoparticle Suspensions with Exchange Cationic Resins

This work describes the optimization of a methodology for the reduction of silver ions from silver nanoparticle suspensions obtained from low-yield laboratory procedures. The laboratory synthesis of silver nanoparticles following a bottom-up approach starting from silver nitrate, originates silver ions that were not reduced to their fundamental state for nanoparticles creation at the end of the process. However, it is well known that silver ions can easily influence chemical assays due to their chemical reactivity properties and can limit biological assays since they interfere with several biological processes, namely intracellular ones, leading to the death of living cells or organisms. As such, the presence of silver ions is highly undesirable when conducting biological assays to evaluate the influence of silver nanoparticles. We report the development of an easy, low-cost, and rapid methodology that is based on cation exchange resins to minimize the silver ion content in a raw suspension of silver nanoparticles while preserving the integrity of the nanomaterials. This procedure preserves the physical-chemical properties of the nanoparticles, thus allowing the purified nanoparticulate systems to be biologically tested. Different types of cationic resins were tested, and the developed methodology was optimized by changing several parameters. A reduction from 92% to 10% of free silver/total silver ratio was achieved when using the Bio-Rad 50W-X8 100–200 mesh resin and a contact time of 15 min. Filtration by vacuum was used to separate the used resin from the nanoparticles suspension, allowing it to be further reused, as well as the purified AgNPs suspension.

[Research progress in the application of external field separation technology and microfluidic technology in the separation of micro/nanoscales]

The micro/nanoscales concerns interactions of entities with sizes in the range of 0.1-100 μm, such as biological cells, proteins, and particles. The separation of micro/nanoscales has been of immense significance for drug development, early-stage cancer detection, and customized precision therapy. For example, in recent years, rapid advances in the field of cell therapy have necessitated the development of simple and effective cell separation techniques. The isolation technique allows the collection of the required stem cells from complex samples. With the development of materials science and precision medicine, the separation of particles is also critical. The key physicochemical properties of micro/nanoscales are highly dependent on their specific size, shape, functional group, and mobility (based on the charged characteristics), which control their performance in the separation system. The current demand has made the simultaneous innovation of a separation system and an on-line detection platform imperative. Accordingly, various analytical methods involving the use of external forces, such as the flow field, magnetic field, electric field, and acoustic field, have been used for micro/nanoscales separation. Based on the physical and chemical parameters of the separation materials, these analytical methods can select different external force fields for micro/nanoscales separation, enabling real-time, accurate, efficient, and selective separation. However, at present, most of the applied field separation technologies require complex equipment and a large sample amount. This makes it crucial to miniaturize and integrate separation technologies for low-cost, rapid, and accurate micro/nanoscales separation. Microfluidic technology is a representative micro/nanoscales separation technology. It requires only a small volume of liquid, making it cost-effective; its high throughput enables continuous separation and analysis; its fast response in a microchip can allow many reactions; and finally, the miniaturization of the device allows the coupling of multiple detectors with the microchip. With the continuous growth and progress of microfluidic technology, some microfluidic platforms are now able to achieve the non-destructive separation of cells. They also enable on-line detection, offer high separation efficiency, and allow rapid separation for different biological samples. This review primarily summarizes recent advances in microfluidic chips based on flow field, electric field, magnetic field, acoustic field, and field separation technologies to improve the micro/nanoscales separation efficiency. This review also discusses the various external force fields of micro/nanoscales, such as a microparticle, single cell separation of substances classified introduction, and summarizes the advantages and disadvantages of their application and development. Finally, the prospect of the combined application of external field separation technology and microfluidic technology in the early screening of cancer cells and for precise micro/nanoscales separation is discussed, and the advantages and potential applications of the combined technology are proposed.

AF4-UV-ICP-MS for detection and quantification of silver nanoparticles in seafood after enzymatic hydrolysis

A method based on asymmetric flow field-flow fractionation (AF4) coupled to ultraviolet-visible (UV-vis) spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS) has been developed for silver nanoparticles (Ag NPs) detection and quantification in bivalve molluscs. Samples were pre-treated using a conventional enzymatic (pancreatin and lipase) hydrolysis procedure (37 °C, 12 h). AF4 was performed using a regenerated cellulose (RC) membrane (10 kDa, 350 μm spacer) and aqueous 5 mM Tris-HCl pH = 7.4 as carrier. AF4 separation was achieved with a program that included a focusing step with tip and focus flows of 0.20 and 3.0 mL min^-1, respectively, and an injection time of 4.0 min. Elution of different size fractions was performed using a cross flow of 3.0 mL min^-1 for 15 min, followed by linear cross flow decrease for 7.5 min, and a washing step for 9.4 min with no cross flow. Several bivalve molluscs (clams, oysters and variegated scallops) were analysed for total Ag content (ICP-MS after microwave assisted acid digestion), and for Ag NPs by the method presented here. Results show that Ag NPs are detected at the same elution time than proteins (UV monitoring at 280 and 405 nm), which suggests a certain interaction occurred between Ag NPs with proteins in the enzymatic extracts. AF4-UV-ICP-MS fractograms also suggest different Ag NPs size distributions for selected samples. Membrane recoveries, determined by peak area comparison of fractograms with and without application of cross flow, were within the 49-121% range. Confirmation of the presence Ag NPs in the investigated enzymatic extracts was demonstrated by SEM after an oxidative pre-treatment based on hydrogen peroxide and microwave irradiation.

Analysis of complex particle mixtures by asymmetrical flow field-flow fractionation coupled to inductively coupled plasma time-of-flight mass spectrometry

Asymmetrical flow field-flow fractionation (AF4) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) has been widely used to characterize metal containing particles. This study demonstrates the advantages of coupling AF4 with ICP-time-of-flight mass spectrometry (ICP-TOFMS) in standard and single particle modes to determine size distribution, elemental composition, and number concentration of composite particles. The coupled system was used to characterize two complex particle mixtures. The first mixture consisted of particles extracted from micro-alloyed steels with two size populations of different elemental composition. The second mixture consisted of particles extracted from soil spiked with various engineered nanoparticles (ENPs). The equivalent hydrodynamic sizes of individual micro-alloyed steel particles were up to 6 times larger than the sizes determined by single particle (sp)-ICP-TOFMS. The larger AF4 sizes were attributed to the presence of a surface coating, which is not reflected in the core size determined by sp-ICP-TOFMS. Two particle populations could not be separated by AF4 due to their broad size distributions but were resolved by sp-ICP-TOFMS using their unique elemental signatures. Multi-angle light scattering and ICP-TOFMS signals of soil suspensions increased with the spiked ENP concentrations. However, only after conducting full element screening and single particle fingerprinting by ICP-TOFMS could this increase be attributed to enhanced extraction efficiency of natural particles and the risk for false conclusions be eliminated. In this study, we describe how AF4 coupled to ICP-TOFMS can be applied to study complex samples of inorganic particles which contain organic compounds.

Silver nanoparticles: Synthesis, investigation techniques, and properties

The unique silver properties, especially in the form of nanoparticles (NPs), allow to utilize them in numerous applications. For instance, Ag NPs can be utilized for the production of electronic and solar energy harvesting devices, in advanced analytical techniques (NALDI, SERS), catalysis and photocatalysis. Moreover, the Ag NPs can be useful in medicine for bioimaging, biosensing as well as in antibacterial and anticancer therapies. The Ag NPs utilization requires comprehensive knowledge about their features regarding the synthesis approaches as well as exploitation conditions. Unfortunately, a large number of scientific articles provide only restricted information according to the objects under investigation. Additionally, the results could be affected by artifacts introduced with exploited equipment, the utilized technique or sample preparation stages. However, it is rather difficult to get information about problems, which may occur during the studies. Thus, the review provides information about novel trends in the Ag NPs synthesis, among which the physical, chemical, and biological approaches can be found. Basic information about approaches for the control of critical parameters of NPs, i.e. size and shape, was also revealed. It was shown, that the reducing agent, stabilizer, the synthesis environment, including trace ions, have a direct impact on the Ag NPs properties. Further, the capabilities of modern analytical techniques for Ag NPs and nanocomposites investigations were shown, among other microscopic (optical, TEM, SEM, STEM, AFM), spectroscopic (UV-Vis, IR, Raman, NMR, electron spectroscopy, XRD), spectrometric (MALDI-TOF MS, SIMS, ICP-MS), and separation (CE, FFF, gel electrophoresis) techniques were described. The limitations and possible artifacts of the techniques were mentioned. A large number of presented techniques is a distinguishing feature, which makes the review different from others. Finally, the physicochemical and biological properties of Ag NPs were demonstrated. It was shown, that Ag NPs features are dependent on their basic parameters, such as size, shape, chemical composition, etc. At the end of the review, the modern theories of the Ag NPs toxic mechanism were shown in a way that has never been presented before. The review should be helpful for scientists in their own studies, as it can help to prepare experiments more carefully.

Evaluation of different strategies for determination of selenomethionine (SeMet) in selenized yeast by asymmetrical flow field flow fractionation coupled to inductively coupled plasma mass spectrometry (AF4-ICP-MS)

This manuscript exemplifies the prospective use of asymmetrical flow field flow fractionation (AF4) coupled to inductively coupled plasma mass spectrometry (ICP-MS) as a simple tool for chemical speciation of selenomethionine (SeMet) in selenized yeast. Several popular sample preparation methods were evaluated for their suitability to determine selenomethionine (SeMet) in selenized yeast by AF4-ICP-MS. These included water, methanesulfonic acid (MSA), formic acid (FA) and alkaline extractions. Alkaline extraction (using sodium dodecyl sulfate buffer) provided the best recovery/determination conditions for SeMet based on analysis of NRC certified reference material (CRM) SELM-1 since it minimized hydrolysis of the protein peptide bonds optimally required for the AF4 separation. The analytical performance of three different AF4 membranes (5, 10 and 500 kDa regenerated cellulose) was also evaluated. No significant difference in the recovery of SeMet was observed when using 5 and 10 kDa RC membranes, whereas the 500 kDa membrane resulted in a significant loss. The proposed method presents appropriate instrument and intra-assay precisions of 4.4-9.2% and 3.8% RSD, respectively, a detection limit of 0.49 μg L-1 SeMet as Se and good linearity with correlation coefficients (R) between 0.996 - 0.999. This is the first report of use of AF4-ICP-MS for species specific quantitation of SeMet in selenized yeast demonstrating its efficient use as an alternative method to other traditional chromatographic techniques.

Lowering the Size Detection Limits of Ag and TiO2 Nanoparticles by Single Particle ICP-MS

As the production and use of engineered nanomaterials increase, there is an urgent need to develop analytical techniques that are sufficiently sensitive to be able to measure the very small nanoparticles (NP) at very low concentrations. Although single particle ICP-MS (SP-ICP-MS) is emerging as one of the best techniques for detecting NP, it is limited by relatively high size detection limits for several NP, including many of the oxides. The use of a high sensitivity sector field ICP-MS (ICP-SF-MS), microsecond dwell times, and dry aerosol sample introduction systems were examined with the goal of lowering the size detection limits of the technique. For samples injected as a wet aerosol, size detection limits as low as 4.9 nm for Ag NP and 19.2 nm for TiO₂ NP were determined. By using a dry aerosol, a significant gain in ion extraction from the plasma was obtained, which resulted in a noticeable decrease of the size detection limits to 3.5 nm for the Ag NP and 12.1 nm for the TiO₂ NP. These substantial improvements were applied to the detection of TiO₂ NP in sunscreen lotions, rainwaters, and swimming pool waters. Concentrations of Ti-containing NP between 27 and 193 μL^-1 were found in rain samples. Similar NP concentrations were detected in public swimming pools, although much higher particle number concentrations (6046 ± 290 μL^-1) were measured in a paddling pool, which was attributed to a high concentration of sunscreen lotions in a small recirculated water volume. High losses of TiO₂ NP through adsorption or agglomeration resulted in recoveries ranging from 14-34%.

Non-spectral interferences in single-particle ICP-MS analysis: An underestimated phenomenon

This work demonstrates the effect of NaCl and carbon-related interferences on the analysis of arsenic and silver nanoparticles (NPs) by single-particle inductively coupled plasma mass spectrometry. Spectral interference caused by ArCl⁺ ions disturbing arsenic NPs analysis was eliminated using ammonia as reaction gas in a dynamic reaction cell of inductively coupled plasma mass spectrometer. In comparison to aqueous dispersions, non-spectral interferences caused by sodium lead to under-evaluation of arsenic and silver NPs diameter by about 7% and 15% at NaCl concentration of 450 mg L^-1 and about 28% and 41% at NaCl concentration of 4500 mg L^-1, respectively. As a consequence of lower transport efficiency, sodium non-spectral interferences also lead to about a 9% lower number of detected NPs for dispersions of both arsenic and silver NPs in 4500 mg L^-1 NaCl. On the contrary, measurement of NPs in matrices containing methanol gives results where Ag and As NPs diameter is over-evaluated by about 3% and 15% at a methanol content of 1% (v/v) and about 6% and 20% at a methanol content of 2% (v/v), respectively, in comparison to aqueous dispersions. In addition, the organic carbon species behave as surfactants and increase the transport efficiency; this leads to an increase in the determined number concentration of NPs. In comparison to aqueous dispersions, this is over-evaluated by about 17% for Ag NPs and about 10% for As NPs at a methanol content of 5% (v/v).

Tracking the Transformation of Nanoparticulate and Ionic Silver at Environmentally Relevant Concentration Levels by Hollow Fiber Flow Field-Flow Fractionation Coupled to ICPMS

It is a great challenge to monitor the physical and chemical transformation of nanoparticles at environmentally relevant concentration levels, mainly because the commonly used techniques like dynamic light scattering and transmission electron microscopy are unable to characterize and quantify trace level nanoparticles in complex matrices. Herein, we demonstrate the on-line coupled system of hollow fiber flow field-flow fractionation (HF5), minicolumn concentration, and inductively coupled plasma mass spectrometry (ICPMS) detection as an efficient approach to study the aggregation and chemical transformation of silver nanoparticles (AgNPs) and ionic Ag species in the aqueous environment at ng/mL levels. Taking advantage of the in-line dialysis of HF5, the selective capture of Ag(I) species by the resin in minicolumn, and the high selectivity and sensitivity of ICPMS detection, we recorded the aggregation of 10 ng/mL AgNPs in complex matrices (e.g., NOM, Na⁺/Ca²⁺), revealing an interesting tiny AgNPs formation process of photoreduction of trace level Ag(I) that is different from larger AgNPs generated at high concentration of Ag(I) by accurate characterization and respectively identifying and quantifying new thiol-complexed Ag(I) and residual Ag(I) in the intertransformation of Ag(I) and AgNPs in domestic wastewater by simultaneously detecting the S and Ag signals via ICPMS.