Recovery Study of Gold Nanoparticle Markers from Lateral Flow Immunoassays.

Lateral flow immunoassays (LFIAs) are a simple diagnostic device used to detect targeted analytes. Wasted and unused rapid antigen lateral flow immunoassays represent mass waste that needs to be broken down and recycled into new material components. The aim of this study was to recover gold nanoparticles that are used as markers in lateral flow immunoassays. For this purpose, a dissolution process with aqua regia was utilised, where gold nanoparticles were released from the lateral flow immunoassay conjugate pads. The obtained solution was then concentrated further with gold chloride salt (HAuCl4) so that it could be used for the synthesis of new gold nanoparticles in the process of ultrasonic spray pyrolysis (USP). Various characterisation methods including scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy and optical emission spectrometry with inductively coupled plasma were used during this study. The results of this study showed that the recovery of gold nanoparticles from lateral flow immunoassays is possible, and the newly synthesised gold nanoparticles represent the possibility for incorporation into new products.

Study of Gold Nanoparticles Conjugated with SARS-CoV-2 S1 Spike Protein Fragments.

This study reports on the successful conjugation of SARS-CoV-2 S1 spike protein fragments with gold nanoparticles (AuNPs) that were synthesised with Ultrasonic Spray Pyrolysis (USP). This method enables the continuous synthesis of AuNPs with a high degree of purity, round shapes, and the formation of a surface that allows various modifications. The conjugation mechanism of USP synthesized AuNPs with SARS-CoV-2 S1 spike protein fragments was investigated. A gel electrophoresis experiment confirmed the successful conjugation of AuNPs with SARS-CoV-2 S1 fragments indirectly. X-ray Photoelectron Spectroscopy (XPS) analysis confirmed the presence of characteristic O1s and N1s peaks, which indicated that specific binding between AuNPs and SARS-CoV-2 S1 spike protein fragments takes place via a peptide bond formed with the citrate stabiliser. This bond is coordinated to the AuNP's surface and the N-terminals of the protein, with the conjugate displaying the expected response within a prototype LFIA test. This study will help in better understanding the behaviour of AuNPs synthesised with USP and their potential use as sensors in colorimetric or electrochemical sensors and LFIA tests.

Study of Ni/Y2O3/Polylactic Acid Composite.

This study demonstrates the successful synthesis of Ni/Y2O3 nanocomposite particles through the application of ultrasound-assisted precipitation using the ultrasonic spray pyrolysis technique. They were collected in a water suspension with polyvinylpyrrolidone (PVP) as the stabiliser. The presence of the Y2O3 core and Ni shell was confirmed with transmission electron microscopy (TEM) and with electron diffraction. The TEM observations revealed the formation of round particles with an average diameter of 466 nm, while the lattice parameter on the Ni particle's surface was measured to be 0.343 nm. The Ni/Y2O3 nanocomposite particle suspensions were lyophilized, to obtain a dried material that was suitable for embedding into a polylactic acid (PLA) matrix. The resulting PLA/Ni/Y2O3 composite material was extruded, and the injection was moulded successfully. Flexural testing of PLA/Ni/Y2O3 showed a slight average decrease (8.55%) in flexural strength and a small decrease from 3.7 to 3.3% strain at the break, when compared to the base PLA. These findings demonstrate the potential for utilising Ni/Y2O3 nanocomposite particles in injection moulding applications and warrant further exploration of their properties and new applications in various fields.

In Vitro Evaluation of the Potential Anticancer Properties of Cu-Based Shape Memory Alloys.

Due to the unique functional properties of shape memory alloys (SMAs) and current scientific interest in Cu-containing biomaterials, a continuously cast Cu-Al-Ni alloy in the form of rods has been investigated as a potential candidate for biomedical application. Additionally, the fact that Cu- complexes have an antitumour effect served as a cornerstone to develop more efficient drugs based on trace element complexes. In line with that, our study aimed to analyse the basic properties of the Cu-Al-Ni alloy, along with its anticancer properties. The detailed chemical analysis of the Cu-Al-Ni alloy was performed using XRF and SEM/EDX analyses. Furthermore, a microstructural and structure investigation was carried out, combined with hardness measurements using the static Vickers method. Observations have shown that the Cu-Al-Ni microstructure is homogeneous, with the presence of typical martensitic laths. XRD analysis confirmed the presence of two phases, ß' (monoclinic) and γ' (orthorhombic). The viability of osteosarcoma cells in contact with the Cu-Al-Ni alloy was evaluated using epifluorescence microscopy, while their morphology and attachment pattern were observed and analysed using a high-resolution SEM microscope. Biocompatibility testing showed that the Cu-Al-Ni alloy exerted a considerable antineoplastic effect.

Physicochemical Properties of Gold Nanoparticles for Skin Care Creams.

Gold nanoparticles (AuNPs) have now been used in skin care creams for several years, with marketed anti-aging, moisturizing, and regenerative properties. Information on the harmful effects of these nanoparticles is lacking, a concern for the use of AuNPs as cosmetic ingredients. Testing AuNPs without the medium of a cosmetic product is a typical method for obtaining this information, which is mainly dependent on their size, shape, surface charge, and dose. As these properties depend on the surrounding medium, nanoparticles should be characterized in a skin cream without extraction from the cream's complex medium as it may alter their physicochemical properties. The current study compares the sizes, morphology, and surface changes of produced dried AuNPs with a polyvinylpyrrolidone (PVP) stabilizer and AuNPs embedded in a cosmetic cream using a variety of characterization techniques (TEM, SEM, DLS, zeta potential, BET, UV-vis). The results show no observable differences in their shapes and sizes (spherical and irregular, average size of 28 nm) while their surface charges changed in the cream, indicating no major modification of their primary sizes, morphology, and the corresponding functional properties. They were present as individually dispersed nanoparticles and as groups or clusters of physically separated primary nanoparticles in both dry form and cream medium, showing suitable stability. Examination of AuNPs in a cosmetic cream is challenging due to the required conditions of various characterization techniques but necessary for obtaining a clear understanding of the AuNPs' properties in cosmetic products as the surrounding medium is a critical factor for determining their beneficial or harmful effects in cosmetic products.

Comparative Study of the Microstructure and Properties of Cast-Fabricated and 3D-Printed Laser-Sintered Co-Cr Alloys for Removable Partial Denture Frameworks.

Since additive technologies in dentistry are gradually replacing metal casting technology, it is necessary to evaluate new dental constructions intended for the development of removable partial denture frameworks. The aim of this research was to evaluate the microstructure and mechanical properties of 3D-printed, laser-melted and -sintered Co-Cr alloys, and perform a comparative study with Co-Cr castings for the same dental purposes. The experiments were divided into two groups. The first group consisted of samples produced by conventional casting of the Co-Cr alloy. The second group consisted of 3D-printed, laser-melted and -sintered specimens produced from a Co-Cr alloy powder divided into three subgroups, depending on the technological parameters chosen for manufacturing (angle, location and heat treatment). Examination of the microstructure was carried out by classical metallographic sample preparation, using optical microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX) analysis. A structural phase analysis was also performed by XRD. The mechanical properties were determined using a standard tensile test. The microstructure observation showed a dendritic character in the case of castings, while in the case of 3D-printed, laser-melted and -sintered Co-Cr alloys, the microstructure was typical for additive technologies. The XRD phase analysis confirmed the presence of Co-Cr phases (ε and γ). The results of the tensile test showed remarkably higher yield and tensile strength values and slightly lower elongation of the 3D-printed, laser-melted and -sintered samples than those produced by conventional casting.

Unraveling the Antibiofilm Activity of a New Nanogold Resin for Dentures and Epithesis.

Dentures and epitheses are mostly made from poly(methyl methacrylate) (PMMA), which does not show antimicrobial properties. They present reservoirs of microorganisms grown in biofilms. The aim of this study is to prepare a PMMA enriched with gold nanoparticles (AuNPs)-PMMA/AuNPs and the examination of its physical, mechanical and antimicrobial properties. The AuNPS were synthetized from HAuCl4 using the ultrasonic spray pyrolysis method with lyophilization. The PMMA/AuNP samples were compared to PMMA samples. Density was measured by pycnometer. Microhardness was evaluated using the Vickers hardness test. Monomicrobial biofilm formation (Streptococcus mitis, Candida albicans, Staphylococcus aureus and Escherichia coli) was measured by colony-forming units (CFUs) and MTT test and visualized by SEM. AuNP release was measured indirectly (the CFUs of the medium around the sample). The density and microhardness of the PMMA/AuNPs were similar to those of the PMMA. CFU and MTT values for the biofilms formed on the PMMA for each of the tested species were higher than those of the biofilms formed on the PMMA/AuNPs. The CFUs of the medium around the sample were similar for both materials. PMMA/AuNPs showed a significant reduction in the monomicrobial biofilms of all tested species. AuNPs are not released from PMMA/AuNPs. Density, indirect measurement of residual monomer and dentures weight were similar between PMMA and PMMA/AuNPs. Microhardness, as a measure of the wear resistance, was also similar between tested discs.

Cast Microstructure of a Complex Concentrated Noble Alloy Ag20Pd20Pt20Cu20Ni20.

A complex concentrated noble alloy (CCNA) of equiatomic composition (Ag20Pd20Pt20Cu20Ni20-20 at. %) was studied as a potential high-performance material. The equiatomic composition was used so that this alloy could be classified in the subgroup of high-entropy alloys (HEA). The alloy was prepared by induction melting at atmospheric pressure, using high purity elements. The degree of metastability of the cast state was estimated on the basis of changes in the microstructure during annealing at high temperatures in a protective atmosphere of argon. Characterisation of the metallographically prepared samples was performed using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Observation shows that the microstructure of the CCNA is in a very metastable state and multiphase, consisting of a continuous base of dendritic solidification-a matrix with an interdendritic region without other microstructural components and complex spheres. A model of the probable flow of metastable solidification of the studied alloy was proposed, based on the separation of L-melts into L1 (rich in Ni) and L2 (rich in Ag). The phenomenon of liquid phase separation in the considered CCNA is based on the monotectic reaction in the Ag-Ni system.

A Nonlinear Probabilistic Pitting Corrosion Model of Ni-Ti Alloy Immersed in Shallow Seawater.

The degradation of metal materials in a marine environment represents the consequence of the electrochemical corrosion of metals under the influence of the environment. The application of new materials in the maritime industry requires experimental, real-world research on the form of corrosive damage and the intensity of the corrosion. This paper analyses the pitting corrosion of a rod-shaped nickel-titanium (Ni-Ti) alloy that was produced by means of the continuous casting method. In total, three samples were posted in a real seawater environment and analysed after 6, 12, and 18 months. Pits were detected on the Ni-Ti alloy after 18 months of exposure to the marine environment. The database on pitting corrosion was created by measuring depth in mm, which was performed by means of a nonlinear method, and by the generation of an artificial database of a total of 120, gauged in critical pit areas. The data were obtained by the application of a nonlinear model, and under the assumption that corrosion starts after 12 months of exposure in the corrosive marine environment. The EDX analysis of the Ni-Ti alloy composition inside the pits and on the edges of the pits indicated that the corrosion process in the hole of the pit occurs due to the degradation of the Ni.

Corrosion of NiTiDiscs in Different Seawater Environments.

This paper gives an approach to the corrosion resistance analysis and changes in the chemical composition of anNiTi alloy in the shape of a disc, depending on different real seawater environments. The NiTi discs were analysed after 6 months of exposure in real seawater environments: the atmosphere, a tidal zone, and seawater. The corrosion tests showed that the highest corrosion rate for the discs is in seawater because this had the highest value of current density, and the initial disc had the most negative potential. Measuring the chemical composition of the discs using inductively coupled plasma and X-ray fluorescence before the experiment and semiquantitative analysis after the experiment showed the chemical composition after 6 months of exposure. Furthermore, the applied principal component analysis and cluster analysis revealed the influence of the different environments on the changes in the chemical composition of the discs. Cluster analysis detected small differences between the similar corrosive influences of the analysed types of environments during the period of exposure. The obtained results confirm that PCA can detect subtle quantitative differences among the corrosive influences of the types of marine environments, although the examined corrosive influences are quite similar. The applied chemometric methods (CA and PCA) are, therefore, sensitive enough to register the existence of slight differences among corrosive environmental influences on the analysed NiTi SMA.

Synthesis of Ni/Y2O3 Nanocomposite through USP and Lyophilisation for Possible Use as Coating.

The Ni/Y2O3 catalyst showed high catalytic activity. Based on this, the aim of this study was to create Ni/Y2O3 nanocomposites powder with two innovative technologies, Ultrasonic Spray Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition of the generated aerosols in an N2/H2 reduction atmosphere caused a complete decomposition of the nickel (II) nitrate to elemental Ni, which became trapped on the formed Y2O3 nanoparticles. The Ni/Y2O3 nanocomposite particles were captured via gas washing in an aqueous solution of polyvinylpyrrolidone (PVP) in collection bottles. PVP was chosen for its ability to stabilise nano-suspensions and as an effective cryoprotectant. Consequently, there was no loss or agglomeration of Ni/Y2O3 nanocomposite material during the lyophilisation process. The Ni/Y2O3 nanocomposite powder was analysed using ICP-MS, SEM-EDX, and XPS, which showed the impact of different precursor concentrations on the final Ni/Y2O3 nanocomposite particle composition. In a final step, highly concentrated Ni/Y2O3 nanocomposite ink (Ni/Y2O3 > 0.140 g/mL) and test coatings from this ink were prepared by applying them on a white matte photo paper sheet. The reflection curve of the prepared Ni/Y2O3 nanocomposite coating showed a local maximum at 440 nm with a value of 39% reflection. Given that Ni is located on the surface of the Ni/Y2O3 nanocomposite in the elemental state and according to the identified properties, tests of the catalytic properties of this coating will be performed in the future.

Oxidation Behaviour of Microstructurally Highly Metastable Ag-La Alloy.

A new silver-based alloy with 2 wt.% of lanthanum (La) was studied as a potential candidate for electric contact material. The alloy was prepared by rapid solidification, performed by the melt spinning technique. Microstructural examination of the rapidly solidified ribbons revealed very fine grains of αAg and intermetallic Ag5La particles, which appear in the volume of the grains, as well as on the grain boundaries. Rapid solidification enabled high microstructural refinement and provided a suitable starting microstructure for the subsequent internal oxidation, resulting in fine submicron-sized La2O3 oxide nanoparticle formation throughout the volume of the silver matrix (αAg). The resulting nanostructured Ag-La2O3 microstructure was characterised by high-resolution FESEM and STEM, both equipped with EDX. High-temperature internal oxidation of the rapidly solidified ribbons essentially changed the microstructure. Mostly homogeneously dispersed nano-sized La2O3 were formed within the grains, as well as on the grain boundaries. Three mechanisms of internal oxidation were identified: (i) the oxidation of La from the solid solution; (ii) partial dissolution of finer Ag5La particles before the internal oxidation front and oxidation of La from the solid solution; and (iii) direct oxidation of coarser Ag5La intermetallic particles.

Material Analysis of the Remains of a Wooden Chest from the 4th Century and a Proposal for Its Reconstruction.

A stone chest found in 1971 near one of the largest early Christian basilicas in Northern Dalmatia (Croatia) contained brass tiles decorated with various biblical scenes. An archaeological study confirmed the thesis that the fragments of brass tiles are most likely the remains of a wooden chest made in the 4th century AD, and that this is one of the best preserved archaeological finds of its kind in the world as one of the biblical scenes shows Mary, together with a record of her name (Maria). Based on the preserved brass tiles, a reconstruction of the wooden chest was made in 1973 with tiles glued onto a plastic frame. Subsequent studies have shown that such a reconstruction was not adequate, as some of the brass tiles were destroyed (disintegrated), and they were not connected properly into a whole that could represent the original. For the new reconstruction of this archaeological object it was necessary to carry out a material analysis, including the chemical composition of the brass tiles, as well as to find a solvent for the glue which could be used to remove the brass tiles from the plastic framework without any additional destruction. Based on extensive investigations and material analyses including the following techniques (SEM, EDX, FTIR, DSC), the starting points for the restoration process of the wooden chest with brass tiles were set, as well as the proposal for the appearance of the new chest.

Gold Inks for Inkjet Printing on Photo Paper: Complementary Characterisation.

Nowadays, cost-effective, available, and flexible paper-based electronics play an essential role in the electronics industry. Herein, we present gold nanoparticles (AuNPs) as a potential raw material for gold inks in the future for such purposes. AuNPs in this research were synthesised using the ultrasonic spray pyrolysis (USP) technique from two precursors: gold (III) chloride tetrahydrate and gold (III) acetate. Synthesised AuNPs were collected in a suspension composed of deionised (D.I.) water and the stabiliser polyvinylpyrrolidone (PVP). AuNPs' suspensions were subjected to the rotavapor process to obtain gold inks with higher Au concentration (>300 ppm). ICP-MS measurements, the size and shape of AuNPs, ζ-potential, Ultraviolet-visible (UV-Vis) spectrophotometry measurements, and scanning electron microscop y (SEM) of gold inks were carried out in order to find the optimal printing parameters. In the final stage, the optical contact angle measurements were performed using a set of polar to non-polar liquids, allowing for the determination of the surface free energy of gold inks. Inkjet printing of gold inks as defined stripes on photo paper were tested, based on the characterisation results.

Bacterial Adhesion of Streptococcus mutans to Dental Material Surfaces.

The aim of this study was to investigate and understand bacterial adhesion to different dental material surfaces like amalgam, Chromasit, an Co-Cr alloy, an IPS InLine ceramic, yttrium stabilized tetragonal polycrystalline zirconia (TPZ), a resin-based composite, an Au-Pt alloy, and a tooth. For all materials, the surface roughness was assessed by profilometry, the surface hydrophobicity was determined by tensiometry, and the zeta potential was measured by electrokinetic phenomena. The arithmetic average roughness was the lowest for the TPZ ceramic (Ra = 0.23 µm ± 0.02 µm), while the highest value was observed for the Au-Pt alloy (Ra = 0.356 µm ± 0.075 µm). The hydrophobicity was the lowest on the TPZ ceramic and the highest on the Co-Cr alloy. All measured streaming potentials were negative. The most important cause of tooth caries is the bacterium Streptococcus mutans, which was chosen for this study. The bacterial adhesion to all material surfaces was determined by scanning electron microscopy. We showed that the lowest bacterial extent was on the amalgam, whereas the greatest extent was on tooth surfaces. In general, measurements showed that surface properties like roughness, hydrophobicity and charge have a significant influence on bacterial adhesion extent. Therefore, dental material development should focus on improving surface characteristics to reduce the risk of secondary caries.

Advances in Ultrasonic Spray Pyrolysis Processing of Noble Metal Nanoparticles-Review.

In the field of synthesis and processing of noble metal nanoparticles, the study of the bottom-up method, called Ultrasonic Spray Pyrolysis (USP), is becoming increasingly important. This review analyses briefly the features of USP, to underline the physical, chemical and technological characteristics for producing nanoparticles and nanoparticle composites with Au and Ag. The main aim is to understand USP parameters, which are responsible for nanoparticle formation. There are two nanoparticle formation mechanisms in USP: Droplet-To-Particle (DTP) and Gas-To-Particle (GTP). This review shows how the USP process is able to produce Au, Ag/TiO2, Au/TiO2, Au/Fe2O3 and Ag/(Y0.95 Eu0.05)2O3 nanoparticles, and presents the mechanisms of formation for a particular type of nanoparticle. Namely, the presented Au and Ag nanoparticles are intended for use in nanomedicine, sensing applications, electrochemical devices and catalysis, in order to benefit from their properties, which cannot be achieved with identical bulk materials. The development of new noble metal nanoparticles with USP is a constant goal in Nanotechnology, with the objective to obtain increasingly predictable final properties of nanoparticles.

Microstructure Characterisation and Identification of the Mechanical and Functional Properties of a New PMMA-ZnO Composite.

In this research work, we synthesised poly(methyl methacrylate) (PMMA) enriched with 2 wt.% zinc oxide nanoparticles (ZnO) through conventional heat polymerisation and characterised its microstructure. It was found that the distribution of ZnO nanoparticles was homogeneous through the volume of the PMMA. The mechanical testing of the PMMA-ZnO composite primarily included the determination of the compressive properties on real dentures, while density measurements were performed using a pycnometer. The testing of functional properties involved the identification of the colour of the new PMMA-ZnO composite, where pure PMMA acted as a control. In the second step, the PMMA-ZnO cytotoxicity assays were measured in vitro, which were shown to be similar to the control PMMA. Based on this, it could be concluded that the newly formed PMMA-ZnO composite did not induce direct or indirect cytotoxic effects in L929 cell cultures; therefore, according to ISO/DIN 10993-5:2009, this composite was categorised as non-cytotoxic.

The Influences of Moisture on the Mechanical, Morphological and Thermogravimetric Properties of Mineral Wool Made from Basalt Glass Fibers.

Mineral wool made from basalt fibers is frequently used as an insulating material in construction systems. In this study, both unused mineral wool and wool obtained from the softened roofing area were comprehensively analyzed in a laboratory using different characterization techniques. Firstly, the initial water content and compressive strength at 10% deformation were determined. Secondly, microstructure and surface chemical composition were analyzed by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). To study heterogeneities near the fiber surface and to examine cross-sectional composition, a scanning transmission electron microscope (STEM) was used. Finally, to verify possible reasons for resin degradation, thermogravimetric analysis and differential scanning colometry (TGA-DSC) were simultaneously carried out. The results show that natural aging under high humidity and thermal fluctuations greatly affected the surface morphology and chemical composition of the fibrous composite. Phenol-formaldehyde and other hydrophobic compounds that protect fibers against moisture and give compressive resistance were found to be degraded.

Novel Approach of Nanostructured Bainitic Steels' Production with Improved Toughness and Strength.

The tendencies of development within the field of engineering materials show a persistent trend towards the increase of strength and toughness. This pressure is particularly pronounced in the field of steels, since they compete with light alloys and composite materials in many applications. The improvement of steels' mechanical properties is sought to be achieved with the formation of exceptionally fine microstructures ranging well into the nanoscale, which enable a substantial increase in strength without being detrimental to toughness. The preferred route by which such a structure can be produced is not by applying the external plastic deformation, but by controlling the phase transformation from austenite into ferrite at low temperatures. The formation of bainite in steels at temperatures lower than about 200 °C enables the obtainment of the bulk nanostructured materials purely by heat treatment. This offers the advantages of high productivity, as well as few constraints in regard to the shape and size of the workpiece when compared with other methods for the production of nanostructured metals. The development of novel bainitic steels was based on high Si or high Al alloys. These groups of steels distinguish a very fine microstructure, comprised predominantly of bainitic ferrite plates, and a small fraction of retained austenite, as well as carbides. The very fine structure, within which the thickness of individual bainitic ferrite plates can be as thin as 5 nm, is obtained purely by quenching and natural ageing, without the use of isothermal transformation, which is characteristic for most bainitic steels. By virtue of their fine structure and low retained austenite content, this group of steels can develop a very high hardness of up to 65 HRC, while retaining a considerable level of impact toughness. The mechanical properties were evaluated by hardness measurements, impact testing of notched and unnotched specimens, as well as compression and tensile tests. Additionally, the steels' microstructures were characterised using light microscopy, field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The obtained results confirmed that the strong refinement of the microstructural elements in the steels results in a combination of extremely high strength and very good toughness.

The Effect of Stabilisation Agents on the Immunomodulatory Properties of Gold Nanoparticles Obtained by Ultrasonic Spray Pyrolysis.

Gold nanoparticles (GNPs) have been investigated extensively as drug carriers in tumour immunotherapy in combination with photothermal therapy. For this purpose, GNPs should be stabilised in biological fluids. The goal of this study was to examine how stabilisation agents influence cytotoxicity and immune response in vitro. Spherical GNPs, 20 nm in size, were prepared by ultrasonic spray pyrolysis (USP). Three types of stabilising agents were used: sodium citrate (SC), polyvinyl-pyrrolidone (PVP), and poly-ethylene glycol (PEG). Pristine, non-stabilised GNPs were used as a control. The culture models were mouse L929 cells, B16F10 melanoma cells and human peripheral blood mononuclear cells (PBMNCs), obtained from healthy donors. Control SC- and PEG-GNPs were non-cytotoxic at concentrations (range 1-100 µg/mL), in contrast to PVP-GNPs, which were cytotoxic at higher concentrations. Control GNPs inhibited the production of IFN-ϒ slightly, and augmented the production of IL-10 by PHA-stimulated PBMNC cultures. PEG-GNPs inhibited the production of pro-inflammatory cytokines (IL-1, IL-6, IL-8, TNF-α) and Th1-related cytokines (IFN-ϒ and IL-12p70), and increased the production of Th2 cytokines (IL-4 and IL-5). SC-PEG inhibited the production of IL-8 and IL-17A. In contrast, PVP-GNPs stimulated the production of pro-inflammatory cytokines, Th1 cytokines, and IL-17A, but also IL-10. When uptake of GNPs by monocytes/macrophages in PBMNC cultures was analysed, the ingestion of PEG- GNPs was significantly lower compared to SC- and PVP-GNPs. In conclusion, stabilisation agents modulate biocompatibility and immune response significantly, so their adequate choice for preparation of GNPs is an important factor when considering the use of GNPs for application in vivo.