DNA Barcoding Meets Nanotechnology: Development of a Universal Colorimetric Test for Food Authentication

Convergent technologies to tackle challenges of modern food authentication

The authentication process involves all the supply chain stakeholders, and it is also adopted to verify food quality and safety. Food authentication tools are an essential part of traceability systems as they provide information on the credibility of origin, species/variety identity, geographical provenance, production entity. Moreover, these systems are useful to evaluate the effect of transformation processes, conservation strategies and the reliability of packaging and distribution flows on food quality and safety. In this manuscript, we identified the innovative characteristics of food authentication systems to respond to market challenges, such as the simplification, the high sensitivity, and the non-destructive ability during authentication procedures. We also discussed the potential of the current identification systems based on molecular markers (chemical, biochemical, genetic) and the effectiveness of new technologies with reference to the miniaturized systems offered by nanotechnologies, and computer vision systems linked to artificial intelligence processes. This overview emphasizes the importance of convergent technologies in food authentication, to support molecular markers with the technological innovation offered by emerging technologies derived from biotechnologies and informatics. The potential of these strategies was evaluated on real examples of high-value food products. Technological innovation can therefore strengthen the system of molecular markers to meet the current market needs; however, food production processes are in profound evolution. The food 3D-printing and the introduction of new raw materials open new challenges for food authentication and this will require both an update of the current regulatory framework, as well as the development and adoption of new analytical systems.

A Portable Nucleic Acid Testing Platform with Photosensitization, a Three-Dimensionally Printed Multipiece Chip, and Digital Color Sensing

Portable nucleic acid testing (NAT) holds great promise for point-of-care disease diagnosis and field-based applications but remains difficult to achieve. Herein, we describe a portable NAT that streamlines loop-mediated isothermal amplification with photosensitization-based color development in a fully sealed 3D-printed multipiece chip. Using a smartphone accessory and an APP, we also introduce a calibration-free quantification approach via digital color sensing and library matching. With these innovative approaches, our detection platform is highly accessible, allowing for rapid and sensitive NAT without requiring sophisticated instruments and well-trained personnel. The field applicability of our NAT platform was demonstrated by detecting tuberculosis infections in clinical sputum samples and food adulteration in commercial salmon meat products.

Dual-color core-shell silica nanosystems for advanced super-resolution biomedical imaging

Fluorescent core-shell silica nanoparticles are largely employed in nanomedicine and life science thanks to the many advantages they offer. Among these, the enhancement of the stability of the fluorescent signal upon fluorophore encapsulation into the silica matrix and the possibility to combine in a single vehicle multiple functionalities, physically separated in different compartments. In this work, we present a new approach to the Stöber method as a two-cycle protocol for the tailored synthesis of dual-color fluorescent core-shell silicon dioxide nanoparticles (SiO2 NPs) using two commercial dyes as model. To facilitate the colloidal stability, the nanoparticle surface was functionalized with biotin by two approaches. The biotinylated nanosystems were characterized by several analytical and advanced microscopy techniques including Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), UV-vis, transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Moreover, advanced super-resolution based on structured illumination was used for the imaging of the double-fluorescent NPs, both on a substrate and in the cellular microenvironment, at nanometric resolution 100 nm, in view of their versatile potential employment in fluorescence optical nanoscopy as nanoscale calibration tools as well as in biomedical applications as biocompatible nanosystems for intracellular biosensing with high flexibility of use, being these nanoplatforms adaptable to the encapsulation of any couple of dyes with the desired function.

A dual-color plasmonic immunosensor for salivary cortisol measurement

Lifestyle-related disorders are a public health problem worldwide and their early diagnosis represents the key to successful therapies. In this framework, rapid point-of-care (POC) tests are one of the most promising diagnostic techniques. In particular, the use of saliva is raising increasing interest as a noninvasive biological fluid in POC systems, although the low concentration of salivary biomarkers typically requires strong advances to improve the device sensitivity. In this study, the plasmonic properties of two differently shaped gold nanoparticles (i.e., nanospheres and nanostars) were combined to develop an efficient paper-based immunosensor for the naked-eye evaluation of salivary cortisol, known as one of the main stress-related biomarkers. Notably, the dual-color system facilitated an immediate and easy evaluation of cortisol levels, based on a blue-to-pink color change of the detection zone. Furthermore, the implemented strategy showed potential applicability as a rapid and portable monitoring system, allowing discriminating different target concentrations.

DNA barcoding, an effective tool for species identification: a review

DNA barcoding is a powerful taxonomic tool to identify and discover species. DNA barcoding utilizes one or more standardized short DNA regions for taxon identification. With the emergence of new sequencing techniques, such as Next-generation sequencing (NGS), ONT MinION nanopore sequencing, and Pac Bio sequencing, DNA barcoding has become more accurate, fast, and reliable. Rapid species identification by DNA barcodes has been used in a variety of fields, including forensic science, control of the food supply chain, and disease understanding. The Consortium for Barcode of Life (CBOL) presents various working groups to identify the universal barcode gene, such as COI in metazoans; rbcL, matK, and ITS in plants; ITS in fungi; 16S rRNA gene in bacteria and archaea, and creating a reference DNA barcode library. In this article, an attempt has been made to analyze the various proposed DNA barcode for different organisms, strengths & limitations, recent advancements in DNA barcoding, and methods to speed up the DNA barcode reference library construction. This study concludes that constructing a reference library with high species coverage would be a major step toward identifying species by DNA barcodes. This can be achieved in a short period of time by using advanced sequencing and data analysis methods.

Assessment of the Genetic Distinctiveness and Uniformity of Pre-Basic Seed Stocks of Italian Ryegrass Varieties

Lolium multiflorum Lam., commonly known as Italian ryegrass, is a forage grass mostly valued for its high palatability and digestibility, along with its high productivity. However, Italian ryegrass has an outbreeding nature and therefore has high genetic heterogeneity within each variety. Consequently, the exclusive use of morphological descriptors in the existing varietal identification and registration process based on the Distinctness, Uniformity, and Stability (DUS) test results in an inadequately precise assessment. The primary objective of this work was to effectively test whether the uniformity observed at the phenological level within each population of Italian ryegrass was confirmed at the genetic level through an SSR marker analysis. In this research, using 12 polymorphic SSR loci, we analyzed 672 samples belonging to 14 different Italian ryegrass commercial varieties to determine the pairwise genetic similarity (GS), verified the distribution of genetic diversity within and among varieties, and investigated the population structure. Although the fourteen commercial varieties did not show elevated genetic differentiation, with only 13% of the total variation attributable to among-cultivar genetic variation, when analyzed as a core, each variety constitutes a genetic cluster on its own, resulting in distinct characteristics from the others, except for two varieties. In this way, by combining a genetic tool with the traditional morphological approach, we were able to limit biases linked to the environmental effect of field trials, assessing the real source of diversity among varieties and concretely answering the key requisites of the Plant Variety Protection (PVP) system.

Paper-Based Multiplexed Colorimetric Device for the Simultaneous Detection of Salivary Biomarkers

In this study, we describe a monolithic and fully integrated paper-based device for the simultaneous detection of three prognostic biomarkers in saliva. The pattern of the proposed multiplexed device is designed with a central sample deposition zone and three identical arms, each containing a pre-treatment and test zone. Its one-step fabrication is realized by CO₂ laser cutting, providing remarkable parallelization and rapidity (ca. 5 s/device). The colorimetric detection is based on the sensitive and selective target-induced reshaping of plasmonic multibranched gold nanoparticles, which exhibit a clear spectral shift (and blue-to-pink color change) in case of non-physiological concentrations of the three salivary biomarkers. A rapid and multiplexed naked-eye or smartphone-based readout of the colorimetric response is achieved within 10 min. A prototype kit for POCT testing is also reported, providing robustness and easy handling of the device.

Molecular Approaches to Agri-Food Traceability and Authentication: An Updated Review

In the last decades, the demand for molecular tools for authenticating and tracing agri-food products has significantly increased. Food safety and quality have gained an increased interest for consumers, producers, and retailers, therefore, the availability of analytical methods for the determination of food authenticity and the detection of major adulterations takes on a fundamental role. Among the different molecular approaches, some techniques such as the molecular markers-based methods are well established, while some innovative approaches such as isothermal amplification-based methods and DNA metabarcoding have only recently found application in the agri-food sector. In this review, we provide an overview of the most widely used molecular techniques for fresh and processed agri-food authentication and traceability, showing their recent advances and applications and discussing their main advantages and limitations. The application of these techniques to agri-food traceability and authentication can contribute a great deal to the reassurance of consumers in terms of transparency and food safety and may allow producers and retailers to adequately promote their products.

A versatile switchable dual-modal colorimetric and photoelectrochemical biosensing strategy via light-controlled sway of a signal-output transverter

A design criterion to construct a versatile dual-modal colorimetric and PEC biosensing platform for switching the corresponding mode freely is proposed via integration of a natural enzyme, light-activated nanozyme and light-controlled swayable signal-output transverter. A switchable dual-modal platform toward DNA analysis is developed as a proof of concept.

Colorimetric Nanoplasmonics to Spot Hyperglycemia From Saliva

Early diagnostics and point-of-care (POC) devices can save people's lives or drastically improve their quality. In particular, millions of diabetic patients worldwide benefit from POC devices for frequent self-monitoring of blood glucose. Yet, this still involves invasive sampling processes, which are quite discomforting for frequent measurements, or implantable devices dedicated to selected chronic patients, thus precluding large-scale monitoring of the globally increasing diabetic disorders. Here, we report a non-invasive colorimetric sensing platform to identify hyperglycemia from saliva. We designed plasmonic multibranched gold nanostructures, able to rapidly change their shape and color (naked-eye detection) in the presence of hyperglycemic conditions. This "reshaping approach" provides a fast visual response and high sensitivity, overcoming common detection issues related to signal (color intensity) losses and bio-matrix interferences. Notably, optimal performances of the assay were achieved in real biological samples, where the biomolecular environment was found to play a key role. Finally, we developed a dipstick prototype as a rapid home-testing kit.

Visual detection of in vitro nucleic acid replication by submicro- and nano-sized materials

The rapid growth of in vitro nucleic acid replication has offered a powerful tool for clinical diagnosis, food safety detection and environmental monitorning. Successful implementation of various isothermal nucleic acid amplification methods enables rapid replication of target sequences without the participant of a thermal cycler. Point-of-need analysis possesses great superiorities in user-friendly, instant results analysis, low manufacturing, and consumable costs. To meet the great challenge of point-of-need analysis, developing simple and rapid visual methods becomes crucial. Submicro- and nanomaterials possess unique surface properties, which enables their rapid response to DNA amplicons. Their unique optical, magnetic, catalytic, and other physical/chemical properties have been frequently employed for the visual detection of in vitro nucleic acid replications. Herein, we aim to review the submicro- and nanomaterials-based visual methods for detection of nucleic acid amplification. The visual methods are classified according to the designing strategies (e.g. LSPR, bridging flocculation, luminescence, catalytic reaction, separation, etc.). The basic principles, merits and drawbacks of each strategy are described. The application in analysis of nucleic acid targets and non-nucleic acid targets are discussed. The main challenges and future research directions are also highlighted in this rapidly emerging field.

A Rapid Colorimetric Assay for On-Site Authentication of Cephalopod Species

A colorimetric assay, exploiting the combination of loop-mediated isothermal amplification (LAMP) with DNA barcoding, was developed to address the authentication of some cephalopod species, a relevant group in the context of seafood traceability, due to the intensive processing from the fishing sites to the shelf. The discriminating strategy relies on accurate design of species-specific LAMP primers within the conventional 5' end of the mitochondrial COI DNA barcode region and allows for the identification of Loligo vulgaris among two closely related and less valuable species. The assay, coupled to rapid genomic DNA extraction, is suitable for large-scale screenings and on-site applications due to its easy procedures, with fast (30 min) and visual readout.

Dispersion state phase diagram of citrate-coated metallic nanoparticles in saline solutions

The fundamental interactions underlying citrate-mediated chemical stability of metal nanoparticles, and their surface characteristics dictating particle dispersion/aggregation in aqueous solutions, are largely unclear. Here, we developed a theoretical model to estimate the stoichiometry of small, charged ligands (like citrate) chemisorbed onto spherical metallic nanoparticles and coupled it with atomistic molecular dynamics simulations to define the uncovered solvent-accessible surface area of the nanoparticle. Then, we integrated coarse-grained molecular dynamics simulations and two-body free energy calculations to define dispersion state phase diagrams for charged metal nanoparticles in a range of medium’s ionic strength, a known trigger for aggregation. Ultraviolet-visible spectroscopy experiments of citrate-capped nanocolloids validated our predictions and extended our results to nanoparticles up to 35 nm. Altogether, our results disclose a complex interplay between the particle size, its surface charge density, and the ionic strength of the medium, which ultimately clarifies how these variables impact colloidal stability.

Citrate-stabilized metallic colloids are key materials towards chemosensing and catalysis applications. Here the authors introduce a new theoretical model to estimate how the stoichiometry of citrate molecules absorbed onto spherical metallic nanoparticles influences their aggregation phenomena.

Dispersion state phase diagram of citrate-coated metallic nanoparticles in saline solutions

The fundamental interactions underlying citrate-mediated chemical stability of metal nanoparticles, and their surface characteristics dictating particle dispersion/aggregation in aqueous solutions, are largely unclear. Here, we developed a theoretical model to estimate the stoichiometry of small, charged ligands (like citrate) chemisorbed onto spherical metallic nanoparticles and coupled it with atomistic molecular dynamics simulations to define the uncovered solvent-accessible surface area of the nanoparticle. Then, we integrated coarse-grained molecular dynamics simulations and two-body free energy calculations to define dispersion state phase diagrams for charged metal nanoparticles in a range of medium’s ionic strength, a known trigger for aggregation. Ultraviolet-visible spectroscopy experiments of citrate-capped nanocolloids validated our predictions and extended our results to nanoparticles up to 35 nm. Altogether, our results disclose a complex interplay between the particle size, its surface charge density, and the ionic strength of the medium, which ultimately clarifies how these variables impact colloidal stability.

An amplification-free colorimetric test for sensitive DNA detection based on the capturing of gold nanoparticle clusters

PCR-free or amplification-free strategies for DNA detection provide an interesting alternative to classical molecular biology techniques, opening new possibilities for on-site diagnostics. In this framework, we present herein an amplification-free colorimetric test for DNA detection, based on the capture of multiple gold nanoparticle (AuNP) clusters onto the surface of magnetic microbeads, leading to an increase of the plasmonic signal and, thus, of the overall sensitivity. Noteworthy, the assay allows the detection of as low as 15 attomoles of target DNA by simple visual inspection. The AuNP-cluster capturing mechanism was investigated by UV-vis, SEM, TEM, and EDX analysis. In a case study of E. coli contamination, the colorimetric test achieves a performance comparable to the reference instrumental PCR technique, enabling the naked-eye detection of 7.5 × 10² CFU μL^-1.

Electrochemical Sensors Coupled with Multivariate Statistical Analysis as Screening Tools for Wine Authentication Issues: A Review

Consumers are increasingly interested in the characteristics of the products they consume, including aroma, taste, and appearance, and hence, scientific research was conducted in order to develop electronic senses devices that mimic the human senses. Thanks to the utilization of electroanalytical techniques that used various sensors modified with different electroactive materials coupled with pattern recognition methods, artificial senses such as electronic tongues (ETs) are widely applied in food analysis for quality and authenticity approaches. This paper summarizes the applications of electrochemical sensors (voltammetric, amperometric, and potentiometric) coupled with unsupervised and supervised pattern recognition methods (principal components analysis (PCA), linear discriminant analysis (LDA), partial least square (PLS) regression, artificial neural network (ANN)) for wine authenticity assessments including the discrimination of varietal and geographical origins, monitoring the ageing processes, vintage year discrimination, and detection of frauds and adulterations. Different wine electrochemical authentication methodologies covering the electrochemical techniques, electrodes types, functionalization sensitive materials and multivariate statistical analysis are emphasized and the main advantages and disadvantages of using the proposed methodologies for real applications were concluded.

Identification of synthetic dyes magenta III (new fuchsin) and rhodamine B as common adulterants in commercial saffron

Saffron is a highly adulterated spice due to its limited production and high costs. Non-saffron plant material is coloured with synthetic dyes to produce counterfeit saffron. Continuous monitoring of the synthetic dyes used in counterfeit saffron is essential because some dyes are not safe for human consumption. In the present study, 104 commercial saffron samples from 16 countries were screened, and 20 samples were found to contain dyes. Thin-Layer Chromatography (TLC) analysis showed adulteration with magenta- and pink- coloured dyes (18 and 2 samples, respectively), which did not correspond to any of the dyes reported earlier. Mass spectrometry analysis identified the magenta-coloured dye as magenta III or new fuchsin and the pink-coloured dye as rhodamine B. Magenta III is regarded as possibly carcinogenic, and rhodamine B was reported to cause local sarcomas. Both of these synthetic dyes are reported as adulterants in saffron for the first time.

An ultrasensitive colorimetric test for the detection of somatic rare mutations in DNA

Targeted therapies for cutaneous melanoma, such as those based on specific BRAF inhibitors, have improved the treatment and enhanced the survival rate of patients who harbor the V600E point mutation in the BRAF gene. However, tissue biopsies to characterize BRAF mutation status are prone to sampling bias, due to the intrinsic heterogeneity of a tumor mass. In contrast, blood biopsies, which analyze circulating tumor DNA (ctDNA), offer the most complete and sensitive characterization of the mutation status of a tumor, provide early and more accurate diagnosis, but they require instrumental and costly molecular tests. Therefore, the development of low-cost but highly sensitive tests for the non-invasive identification of BRAFV600E mutation in ctDNA would be of great clinical utility as a routine screening for the early identification of responsive patients and the follow-up of targeted therapy's response. The present work developed a naked-eye, inexpensive, yet very specific colorimetric assay, whose sensitivity is suitable for the detection of BRAFV600E rare mutation in ctDNA. Such test potentially may detect at an early stage the mutation in the tumor mass, when the first mutated cells appear in the blood, by using minimal instrumentation and thus enabling its widespread implementation in the clinics, even in local, minimally equipped laboratories. Indeed, the test detects 0.5% of BRAFV600E in an excess of BRAFWT DNA, which matches the sensitivity of some commercial instrumental assays. Such sensitivity is thus clinically relevant for diagnostic purposes, allowing the early identification of drug-sensitive patients.

Review of Recent DNA-Based Methods for Main Food-Authentication Topics

Adulteration and mislabeling of food products and the commercial fraud derived, either intentionally or not, is a global source of economic fraud to consumers but also to all stakeholders involved in food production and distribution. Legislation has been enforced all over the world aimed at guaranteeing the authenticity of the food products all along the distribution chain, thereby avoiding food fraud and adulteration. Accordingly, there is a growing need for new analytical methods able to verify that all the ingredients included in a foodstuff match the qualities claimed by the manufacturer or distributor. In this sense, the improved performance of most recent DNA-based tools in term of sensitivity, multiplexing ability, high-throughput, and relatively low-cost give them a game-changing role in food-authenticity-related topics. Here, we provide a thorough and updated vision on the recently reported approaches that are applying these DNA-based tools to assess the authenticity of food components and products.

Food Tracking Perspective: DNA Metabarcoding to Identify Plant Composition in Complex and Processed Food Products

One of the main goals of the quality control evaluation is to identify contaminants in raw material, or contamination after a food is processed and before it is placed on the market. During the treatment processes, contamination, both accidental and economically motivated, can generate incongruence between declared and real composition. In our study, we evaluated if DNA metabarcoding is a suitable tool for unveiling the composition of processed food, when it contains small trace amounts. We tested this method on different types of commercial plant products by using tnrL marker and we applied amplicon-based high-throughput sequencing techniques to identify plant components in different food products. Our results showed that DNA metabarcoding can be an effective approach for food traceability in different type of processed food. Indeed, the vast majority of our samples, we identified the species composition as the labels reported. Although some critical issues still exist, mostly deriving from the starting composition (i.e., variable complexity in taxa composition) of the sample itself and the different processing level (i.e., high or low DNA degradation), our data confirmed the potential of the DNA metabarcoding approach also in quantitative analyses for food composition quality control.

Development of a DNA Barcoding-Like Approach to Detect Mustard Allergens in Wheat Flours

The spread of food allergens is a topic of global importance due to its impact on public health. National and International regulations ask food producers and manufacturers to declare product compositions on the label, especially in case of processed raw materials. Wheat flour (Triticum aestivum) can be contaminated by a wide range of species belonging to the Brassicaceae in the field or during grain harvests, storage, and processing. Among them, mustards (Brassica nigra, Brassica juncea and Sinapis alba) are well known allergenic species. Often, food quality laboratories adopt an ELISA approach to detect the presence of mustard species. However, this approach shows cross-reactivity with other non-allergenic species such as Brassica napus (rapeseed). In the last few years, DNA barcoding was proposed as a valid identification method, and it is now commonly used in the authentication of food products. This study aims to set up an easy and rapid DNA-based tool to detect mustard allergenic species. DNA barcoding (matK and ITS2) and chromosome markers (A6, B, C1 genome regions) were selected, and specific primers were validated on incurred reference food matrices. The developed test was proven to be able to distinguish mustard from rapeseed and wheat, overcoming cross-reactivity with Brassica napus.

A Facile, Label-Free, and Universal Biosensor Platform Based on Target-Induced Graphene Oxide Constrained DNA Dissociation Coupling with Improved Strand Displacement Amplification

In this work, we report a low-cost and easy operation biosensor platform capable of detection of various analytes with high sensitivity and good selectivity. By ingeniously assigning the specific aptamer into a primer-template integrated DNA template, and using monolayer graphene oxide as a reversible and nonspecific inhibitor, the simple biosensor platform is set up. Without a target, the DNA template is constrained by the graphene oxide sheet and results in low signal. In the presence of a target, the constrained DNA template is released from the graphene oxide surface via a target-induced aptamer conformational change, and further amplified through the improved strand displacement amplification reaction. Therefore, the target detection is simply converted to DNA detection, and a correlation between target concentration and fluorescence signal can be set up. As a result, dozens-fold signal enhancement, high sensitivity, good selectivity, and potential practicability are achieved in target detection. More importantly, the proposed biosensor platform is versatile, meaning that it can greatly facilitate the detection of a variety of analytes. Due to the low cost and easy availability of sensing materials, and the elimination of tedious detection operations, we believe that this simple and universal biosensor platform can find wide applications in biological assay and environment monitoring.

From the Field to the Bottle—An Integrated Strategy for Wine Authenticity

The wine sector is one of the most economically important agro-food businesses. The wine market value is largely associated to terroir, in some cases resulting in highly expensive wines that attract fraudulent practices. The existent wine traceability system has some limitations that can be overcome with the development of new technological approaches that can tackle this problem with several means. This review aims to call attention to the problem and to present several strategies that can assure a more reliable and authentic wine system, identifying existent technologies developed for the sector, which can be incorporated into the current traceability system.

Advances in DNA Barcoding of Toxic Marine Organisms

There are more than 200,000 marine species worldwide. These include many important economic species, such as large yellow croaker, ribbonfish, tuna, and salmon, but also many potentially toxic species, such as blue-green algae, diatoms, cnidarians, ctenophores, Nassarius spp., and pufferfish. However, some edible and toxic species may look similar, and the correct identification of marine species is thus a major issue. The failure of traditional classification methods in certain species has promoted the use of DNA barcoding, which uses short, standard DNA fragments to assist with species identification. In this review, we summarize recent advances in DNA barcoding of toxic marine species such as jellyfish and pufferfish, using genes including cytochrome oxidase I gene (COI), cytochrome b gene (cytb), 16S rDNA, internal transcribed spacer (ITS), and Ribulose-1,5-bisphosphate carboxylase oxygenase gene (rbcL). We also discuss the application of this technique for improving the identification of marine species. The use of DNA barcoding can benefit the studies of biological diversity, biogeography, food safety, and the detection of both invasive and new species. However, the technique has limitations, particularly for the analysis of complex objects and the selection of standard DNA barcodes. The development of high-throughput methods may offer solutions to some of these issues.

Metallic Nanoparticles: General Research Approaches to Immunological Characterization

Our immunity is guaranteed by a complex system that includes specialized cells and active molecules working in a spatially and temporally coordinated manner. Interaction of nanomaterials with the immune system and their potential immunotoxicity are key aspects for an exhaustive biological characterization. Several assays can be used to unravel the immunological features of nanoparticles, each one giving information on specific pathways leading to immune activation or immune suppression. Size, shape, and surface chemistry determine the surrounding corona, mainly formed by soluble proteins, hence, the biological identity of nanoparticles released in cell culture conditions or in a living organism. Here, we review the main laboratory characterization steps and immunological approaches that can be used to understand and predict the responses of the immune system to frequently utilized metallic or metal-containing nanoparticles, in view of their potential uses in diagnostics and selected therapeutic treatments.