Attachment Of Nanoparticles Research Articles

Nanoparticle attachment promotes nugget effect of Au-rich metallic melts in hydrothermal ore deposits

Nanoparticle attachment promotes nugget effect of Au-rich metallic melts in hydrothermal ore deposits

Bimetallic PdPt Nanoparticles Decorated PES Membranes for Enhanced H2 Separation.

Hydrogen separation has significant importance in diverse applications ranging from clean energy production to gas purification. Membrane technology stands out as a low-cost and efficient method to address the purpose. The development of efficient gas-sensitive materials can further bolster the membrane's performance. In this pursuit, bimetallic PdPt nanoparticles were synthesized using a wet chemical approach and were strategically decorated onto poly(ether sulfone) (PES) membranes. The fibrous morphology of the PES membranes provided an ideal platform for the decoration of nanoparticles, promising enhanced gas transport properties. Prior to the attachment of nanoparticles, the membranes were pretreated under UV light to enhance their surface properties and facilitate improved adhesion. The synthesized bimetallic nanoparticles were characterized by using transmission electron microscopy and X-ray photoelectron spectroscopy for their morphological and elemental analysis. Furthermore, the engineered membranes were characterized using various techniques, such as Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy (FESEM) with rigorous scrutiny to ensure a comprehensive understanding of their structural, chemical, and morphological properties. The membranes were examined for their separation performance using pure H2, N2, and CO2 gases, and the results revealed a 30% increment in H2 permeability and 40 and 42% increments in H2/CO2 and H2/N2 selectivity, respectively. These findings confirmed the critical role of tailored material design and synthesis strategies in advancing membrane technologies for H2 separation applications.

Predicting the removal efficiency of titanium dioxide nanoparticles in an activated sludge system using fate modeling depending on the operating conditions

Wastewater treatment plants (WWTPs) are a major discharge pathway for engineered nanoparticles (ENPs) that can potentially impact aquatic systems, making it crucial to understand ENP behavior in these facilities. In this study, we developed a fate model for titanium dioxide (TiO2) nanoparticles (NPs) to predict their removal efficiency (RE) in activated sludge (AS) systems. The model, based on material balance equations for free and sludge-attached TiO2 NPs, incorporated a linear-adsorption partition coefficient (Kd) and pseudo-second-order kinetics for TiO2 NP attachment to the activated sludge. Validated with data from three WWTPs, the model investigated RE correlations with inflow TiO2 NP concentration, sludge retention time (SRT), hydraulic retention time (HRT), mixed liquor suspended solid (MLSS) concentration, and water temperature. The model reasonably predicted the comparative performance of the WWTPs but underestimated the RE by up to ∼29 %, probably due to system simplification, limited Kd data, the presence of other Ti-containing NPs besides TiO2 NPs, and unincorporated removal mechanisms such as sweeping in the secondary clarifier. The model revealed favorable design/operating conditions for increasing the TiO2 NP RE of the AS system: shortening the SRT, increasing the MLSS concentration, and increasing the water temperature. The developed model could be useful for estimating and comparing the expected TiO2 NP REs across different WWTPs under varying operating conditions or for tracing the material flow and fate of TiO2 NPs in environmental compartments involving WWTPs, both regionally and country-wide.

Fuel Cell Catalyst Layers with Platinum Nanoparticles Synthesized by Sputtering onto Liquid Substrates.

Platinum (Pt) nanoparticles are widely used as catalysts in proton exchange membrane fuel cells. In recent decades, sputter deposition onto liquid substrates has emerged as a potential alternative for nanoparticle synthesis, offering a synthesis process free of contaminant oxygen, capping agents, and chemical precursors. Here, we present a method for the synthesis of supported nanoparticles based on magnetron sputtering onto liquid poly(ethylene glycol) (PEG) combined with a heat-treatment step for attachment of nanoparticles to a carbon support. Transmission electron microscopy imaging reveals Pt nanoparticle growth during the heat-treatment process, facilitated by the carbon support and the reducing properties of PEG. Following the heat treatment, a bimodal size distribution of Pt nanoparticles is observed, with sizes of 2.5 ± 0.8 and 6.7 ± 1.8 nm, compared to 1.8 ± 0.4 nm after sputtering. Synthesized Pt nanoparticles display excellent specific and mass activities for the oxygen reduction reaction, with 1.75 mA/cm2 Pt and 0.27 A/mgPt respectively, measured at 0.9 V vs the reversible hydrogen electrode. The specific activities reported herein outperform literature values of commercial Pt/C catalysts with similar loading and are on par with values of bulk Pt and mass-selected nanoparticles of comparable size. Also, the mass activities agree well with the literature values. The results provide new insights into the growth processes of SoL-synthesized carbon-supported Pt catalyst nanoparticles, and most crucially, the high performance of the synthesized catalyst layers, along with the possibility of nanoparticle growth through a straightforward heat-treatment step at relatively low temperatures, offer a scalable new approach for producing fuel cell catalysts with more efficient material utilization and new material combinations.

Synthesis of metal nanoparticles on graphene oxide and antibacterial properties.

Pathogen-induced infections and the rise of antibiotic-resistant bacteria, such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), pose significant global health challenges, emphasizing the need for new antimicrobial strategies. In this study, we synthesized graphene oxide (GO)-based composites functionalized with silver nanoparticles (AgNPs) and copper nanoparticles (CuNPs) as potential alternatives to traditional antibiotics. The objective is to assess the antibacterial properties of these composites and explore their efficacy against E. coli and S. aureus, two common bacterial pathogens. The composites are prepared using eco-friendly and conventional methods to ensure effective nanoparticle attachment to the GO surface. Structural and morphological characteristics are confirmed through SEM, AFM, EDS, XRD, UV-vis, FTIR, and Raman spectroscopy. The antibacterial efficacy of the composites is tested through disk diffusion assays, colony-forming unit (CFU) counts, and turbidimetry analysis, with an emphasis on understanding the effects of different nanoparticle concentrations. The results demonstrated a dose-dependent antibacterial effect, with GO/AgNP-1 showing superior antibacterial activity over GO/AgNP-2, particularly at lower concentrations (32.0μg/mL and 62.5μg/mL). The GO/CuNP composite also exhibited significant antibacterial properties, with optimal performance at 62.5μg/mL for both bacterial strains. Turbidimetry analysis confirmed the inhibition of bacterial growth, especially at moderate concentrations, although slight nanoparticle aggregation at higher doses reduced efficacy. Lastly, both GO/AgNP and GO/CuNP composites demonstrated significant antibacterial potential. The results emphasize the need to fine-tune nanoparticle concentration and refine synthesis techniques to improve their efficacy, positioning these composites as strong contenders for antimicrobial use.

An amplified voltammetric immunosensor for detection of porcine serum albumin using a self-standing nanohybrid composed of multi-walled carbon nanotubes, polyelectrolytes, and gold nanoparticles

Here, we introduce an innovative approach for signal amplification of a voltammetric immunosensor platform with nanoporous alumina (NPA) millirods to specifically target porcine serum albumin (PSA). A self-standing nanohybrid was constructed using a layer-by-layer assembly technique, which involved coating multi-walled carbon nanotube (MWCNTs) with polyelectrolytes (PEs) and subsequent attachment of multiple gold nanoparticles (AuNPs). The PEs improved dispersion of the MWCNTs and facilitated attachment to multiple AuNPs for enhanced bioconjugation with anti-PSA detection (α-PSAD) antibodies. The morphology of the nanohybrid was examined using field-emission scanning electron microscopy. The resulting MWCNT/PE/AuNP/α-PSAD-bioconjugated nanohybrid acted as an amplified signaling probe for the PSA-specific, NPA millirod-based voltammetric immunosensor. A current value recorded at +0.68 V (vs. Ag/AgCl reference electrode) in the voltammogram served as the analytical signal for quantification, thereby eliminating the need to analyze peak characteristics. Demonstrating remarkable sensitivity, the nanohybrid achieved a PSA detection limit of 0.5 pg/mL, surpassing the 50 pg/mL limit of an immunosensor using a single AuNP for signaling. The proposed nanohybrid offers a superior solution for highly sensitive detection of PSA in voltammetric immunosensor applications.

Enhanced high-temperature mechanical properties and strengthening mechanisms of chemically prepared nano-TiC reinforced IN738LC via laser powder bed fusion

Fabrication of high-strength nickel-based composites to meet the demanding service requirements in aerospace environments is a significant challenge. This paper introduces the wet chemical method to prepare the nano-TiC reinforced IN738LC. In contrast to the conventional ball milling approach, this method attains superior attachment of nanoparticles. By employing a full-factorial experimental design, the correlation between Laser-powder bed fusion (L-PBF) processing parameters and the porosity, micro-hardness, and high-temperature tensile strength of as-built samples was examined. The results indicate that the optimal processing parameters are a laser power of 225 W, scanning speed of 750 mm/s, and hatch space of 0.09 mm, with a Volumetric energy density (VED) of 111.1 J/mm3. Compared to IN738LC, the chemically prepared TiC-IN738LC exhibits a 45 % increase in room temperature tensile strength (400 MPa) and a 65 % increase in high-temperature tensile strength (120 MPa). Compared with ball-milled TiC-IN738LC, the chemically prepared samples present superior microstructure with more equiaxed grains. The morphological analysis of the tensile samples reveals that the presence of dimples are crucial in enhancing the ductility properties. Furthermore, this study identifies the Orowan strengthening mechanism and the grain refinement strengthening mechanism as the principal mechanisms of reinforcement by nano-ceramics.

Bio-inspired fabrication of Ag-ZnO nanoparticle decorated Nylon 11 nanofibers: Multifunctional membrane for environmental remediation

Traditional wastewater treatment methods using nanoparticles encounter challenges with catalyst recovery. In this study, we fabricated a Nylon 11 nanofibrous membrane (NFM) via electrospinning and functionalized it with polydopamine to immobilize Ag-ZnO nanoparticles for photocatalytic degradation of organic pollutants. The Nylon 11 NFM was treated with a dopamine tris buffer solution for polydopamine (PDA) coating, which facilitated mussel-inspired attachment of the ZnO nanoparticles. These nanoparticles served as a nucleation site for the biomimetic nucleation of Ag-ZnONPs during the hydrothermal process. The synthesized composite membrane was characterized by various microscopic and spectroscopic techniques. The water contact angle decreased from 135° (Nylon 11 NFM) to 41° (PDA/Nylon 11 NFM) and the filtration efficiency improved 10 folds (from 15.92 Lm-2 hr-1 to 170.60 Lm-2hr-1) at ambient conditions. The Ag-ZnO/PDA/Nylon 11 NFM showed strong antimicrobial activity against different bacterial strains and excellent photocatalytic degradation for methyl orange with a rate constant of 0.0431 min-1, significantly surpassing other configurations. The membrane exhibited excellent stability, reusability and consistent photocatalytic efficiency over multiple cycles. It is easily recoverable from the reaction mixture, and suitable for repeated use, making it a promising candidate for environmental remediation due to its antibacterial properties, photocatalytic activity, enhanced filtration efficiency, and reusability.

Nanoparticle transport in partially saturated porous media: Attachment at fluid interfaces

Like the solid-water interface (SWI), air-water and oil-water interfaces (AWI and OWI) also act as collectors for nano-sized particles in porous media. The attachment of hydrophobic nanoparticles, which is often favorable and irreversible, is of particular interest because the transport and retention of such particles is closely linked to the fate of nanoplastics in unsaturated subsurface environments and the success of nanoremediation practices. Here, we show how a pore-network model (PNM) can be used to upscale the kinetics and extent of irreversible nanoparticle attachment at a single fluid-fluid interface under conditions of advection and dispersion in a sphere packing. By focusing on a trapped (immobile) non-wetting phase, we highlight a fundamental difference between the single-collector contact efficiency of AWI/OWI and SWI. Namely, AWI/OWI collectors, which are largely by-passed by the flowing aqueous phase, are exposed to a hydrodynamic environment dominated by diffusion. This difference has profound implications for the modelling of nanoparticle transport in porous media at the continuum (Darcy) scale. This study reveals the potential of pore network modelling as an essential complement to continuum models for upscaling the behavior of nanocolloids in porous media.

Enhancement of therapeutic efficacy of Brinzolamide for Glaucoma by nanocrystallization and tyloxapol addition

BackgroundBrinzolamide (BRI) suspensions are used for the treatment of glaucoma; however, sufficient drug delivery to the target tissue after eye drop administration is hampered by poor solubility. To address this issue, we focused on nanocrystal technology, which is expected to improve the bioavailability of poor-solubility drugs, and investigated the effect of BRI nanocrystal formulations on corneal permeability and intraocular pressure (IOP)-reducing effect.MethodsBRI nanocrystal formulations were prepared by the wet-milling method with beads and additives. The particle size was measured by NANOSIGHT LM10, and the morphology was determined using a scanning probe microscope (SPM-9700) and a scanning electron microscope (SEM). Corneal permeability was evaluated in vitro using a Franz diffusion cell with rat corneas and in vivo using rabbits, and the IOP-reducing effect was investigated using a rabbit hypertensive model.ResultsThe particle size range for prepared BRI nanocrystal formulation was from 50 to 300 nm and the mean particle size was 135 ± 4 nm. The morphology was crystalline, and the nanoparticles were uniformly dispersed. In the corneal permeability study, BRI nanocrystallization exhibited higher corneal permeability than non-milled formulations. This result may be attributed to the increased solubility of BRI by nanocrystallization and the induction of energy-dependent endocytosis by the attachment of BRI nanoparticles to the cell membrane. Furthermore, the addition of tyloxapol to BRI nanocrystal formulation further improved the intraocular penetration of BRI and showed a stronger IOP-reducing effect than the commercial product.ConclusionsThe combination of BRI nanocrystallization and tyloxapol is expected to be highly effective in glaucoma treatment and a useful tool for new ophthalmic drug delivery.

Probing the interaction mechanisms of lipid nanoparticle-encapsulated mRNA with surfaces of diverse functional groups: Implication for mRNA transport

The transport of mRNA plays an indispensable role in vaccine drug delivery and emerging therapies. The attachment of lipid nanoparticle encapsulating mRNA (mRNA-LNP) to biological and engineering surfaces is determined by their intermolecular and surface interactions. In this work, the interactions between mRNA-LNP and surfaces with various functional groups were investigated using atomic force microscopy. The results show that mRNA chains are coiled in LNPs, and the surface charges of mRNA are screened by the surrounding lipid molecules. Approach force curves demonstrate that the steric repulsion varies with functional groups. Force mapping reveals that the intermolecular interactions, i.e., hydrogen bonding and electrostatic interaction, contribute to the adhesion. The –OH group is suggested as the most probable binding site for mRNA-LNP attachment. This work provides new insights into mRNA transport mechanisms at biological and engineering surfaces, with useful implications for designing novel nanocarriers and developing functional surfaces for biological applications.

Versatile, reusable and highly sensitive SERS-based point-of-care testing microplatform for reliable ATP detection

The advancement in miniaturized Raman spectrometers, coupled with the single-molecule-level sensitivity and unique fingerprint identification capability of surface-enhanced Raman scattering (SERS), offers great potential for point-of-care testing (POCT). Despite this, accurately quantifying analyte molecules, particularly in complex samples with limited sample volumes, remains difficult. Herein, we present a versatile and reusable SERS microplatform for highly sensitive and reliable quantitative detection of adenosine triphosphate (ATP) in biological fluids. The platform utilizes gold-Prussian blue core-shell nanoparticles modified with polyethyleneimine (Au@PB@PEI NPs), embedded within gold nanoparticle-immobilized capillary-based silica monolithic materials. PB acts as an internal standard, while PEI enhances molecular capture. The periodic, bimodal porous structure of the silica monolithic materials provides uniform and abundant sites for nanoparticle attachment, facilitating rapid liquid permeation, intense SERS enhancement, and efficient enrichment. The platform regulates ATP capture and release through magnesium ions in the liquid phase, eliminating matrix interferences and enabling platform reuse. Integrating efficient molecular enrichment, separation, an interference-free internal standard, a liquid flow channel, and a detection chamber, our platform offers simplicity in operation, exceptional sensitivity and accuracy, and rapid analysis (∼10 min). Employing PB as an internal calibration standard, ratiometric Raman signals (I732/I2123) facilitate precise ATP quantification, achieving a remarkable limit of detection down to 0.62 pM. Furthermore, this platform has been proven to be highly reproducible and validated for ATP quantification in both mouse cerebrospinal fluid and human serum, underscoring its immense potential for POCT applications.

Neutron and X-ray Scattering Characterization of Silica Nanoparticle-Stabilized Polymer Hybrid Latex Particles.

A robust route to produce poly(methyl methacrylate) (pMMA) hybrid latex particles (radius ∼250 nm) that are selectively "armored" with silica nanoparticles (radius 12.5 nm) through addition of vinyltriethoxysilane was previously shown ( J. Colloid Interface Sci. 2018, 528, 289-300).Depending on synthesis conditions, the extent of nanoparticle attachment could be varied; however, the mechanism behind this attachment during latex growth remained unclear. The dual population of particles present (silica + polymer) means that particle sizing by dynamic light scattering is ambiguous. Furthermore, the low glass transition temperature (Tg) of polymers such as poly(butyl acrylate) (pBA) typically used in film-forming applications for decorative coatings (i.e., paints) means that the hybrid latex particles are too "soft" for robust analysis through atomic force microscopy (AFM) and scanning electron microscopy (SEM). Here, we show that small- and ultrasmall-angle neutron scattering (SANS and USANS), along with complementary data from small-angle X-ray scattering (SAXS), reveals that these armored hybrid latex particles adopt a raspberry-type configuration, supporting their core-shell structure. The number of nanoparticles present on the surface of the hybrid latex can be adjusted by addition of one of a diverse range of alkyl- or perfluoroalkyl-silanes to alter silica nanoparticle hydrophobicity, and quantified through analysis of scattering data. The approach therefore provides a novel, nonperturbative, and in situ method of quantifying nanoparticle attachment to polymer latex particles.

The effect of charge screening for cationic surfactants on the rigidity of interfacial nanoparticle assemblies

HypothesisFunctionalizing colloidal particles with oppositely charged surfactants is crucial for stabilizing emulsions, foams, all-liquid structures, and bijels. However, surfactants can reduce the attachment energy, the driving force for colloidal self-assembly at interfaces. An open question remains on how the inherent interfacial activity of cationic surfactants influences the interfacial rigidity of particle-laden interfaces. We hypothesize that charge screening among cationic surfactants regulates the rigidity of oil/water interfaces by reducing the attachment energy of nanoparticles. ExperimentsWe investigate the interfacial rigidity of cetyltrimethylammonium bromide (CTAB) functionalized silica nanoparticles (Ludox® TMA) by analyzing the shape deformation of 1,4-butanediol diacrylate (BDA) droplets under varying salt and alcohol concentrations. The nanoparticle packing density is assessed using scanning electron microscopy. Attachment energy is characterized through interfacial tension measurements, three-phase contact angle analysis, and CTAB adsorption studies. We also examine the effects of interfacial rigidities on the structure of bijel films formed via roll-to-roll solvent transfer-induced phase separation (R2R-STrIPS) using confocal laser scanning microscopy. FindingsIncreasing salt and alcohol concentrations decrease the interfacial rigidity of CTAB-functionalized nanoparticle films by reducing the interfacial tension. The contact angle has a minor influence on the rigidity. These results indicate that CTAB charge screening weakens the nanoparticle attachment energy to the interface. Controlling the rigidity enables the mass production of bijel sheets with consistent flatness, which is crucial for their potential applications in catalysis, energy storage, tissue engineering, and filtration membranes.

Role of Solvents in Oriented Attachment of Ag Nanoparticles: Insights from Molecular Dynamics Simulations and Topological Analysis.

Although the solvation force is considered one of the key forces behind the oriented attachment (OA), the precise roles of solvents in this process remain incompletely elucidated. In this study, we examined the effect of solvent polarities (water, acetone, and chloroform) on the attachment of silver nanoparticles by calculating the free energy curves for the OA process. The observed magnitudes of the binding energies and approaching and dissociation energy barriers are commensurate with the respective solvent polarities. Consequently, OA is more likely to occur in acetone with an intermediate permittivity relative to that of water and chloroform. Additionally, we identified a topological descriptor, namely, the Euler characteristic, of the solvent network, especially the water network, between two approaching surfaces, which manifests a linear correlation with the observed free energy profiles. This descriptor holds promise as a quantitative tool for predicting interactions between nanoparticles in solvent environments featuring hydrogen bond networks.

Electrodeposition strategies for synthetic highly dispersed Ru-decorated Co(OH)2 nanoneedles as advanced hydrogen evolution reaction catalysts

Ru-based nanomaterials have a lot of potential as electrochemical hydrogen evolution reaction (HER) catalysts; however, achieving a uniform dispersion of Ru nanoparticles on substrate materials remains a key challenge. To achieve this, in the current study, we formed NF/Co(OH)2/Ru by electrodepositing Ru nanoparticles onto Co(OH)2 nanoneedles. The Co and O vacancies in the sample promoted water decomposition and the cleavage of O-H bonds, while the high surface energies at the apexes of the Co(OH)2 nanoneedles supported the even growth and attachment of Ru nanoparticles. In addition, the electron-rich Ru nanoparticles aided in the desorption of hydrogen intermediates. Compared to recently published Ru-based HER materials, the NF/Co(OH)2/Ru material created in this study shown improved electrochemical characteristics, with an overpotential of 20 mV at 10 mA·cm−2 and a Tafel slope of 35.43 mV·dec−1. Therefore, this material and the findings of this study are expected to contribute to HER research.

Oriented attachment of silver nanoparticles in DMSO by collapsing under thermal stress

Nowadays, understanding the behavior of nanoparticle agglomeration is crucial to gain insight into the fundamental physicochemical processes that govern particle interactions at the nanoscale. In this work, we are focused on the thermal collapse of silver nanoparticles (NPs) stabilized with sodium citrate in dimethyl sulfoxide (DMSO). Therefore, we investigated the parameters that influence the transition from nearly isolated particles to elongated Ag agglomerates using Dynamic Light Scattering (DLS) and Ultraviolet-Visible Spectroscopy (UV-Vis). In addition, we conducted an in-depth study of the near-particle-particle interaction within the agglomerate using High-Resolution Transmission Electron Microscopy (HRTEM) observations of the agglomerates. The HRTEM results suggest that in the elongation of the agglomerate, the oriented attachment within the initial cluster plays a crucial role in the alignment along the longitudinal axis. The aging colloid exhibits minimal agglomeration, suggesting that the driving force of the collapse phenomenon is predominantly thermodynamic rather than kinetic in nature, and that the surface chemical equilibria play a key role in the preferential orientation mechanism.

EGaIn-Modified ePADs for Simultaneous Detection of Homocysteine and C-Reactive Protein in Saliva toward Early Diagnosis of Cardiovascular Disease.

Homocysteine (Hcy) and C-reactive protein (CRP) are critical biomarkers for numerous chronic diseases, with cardiovascular disease (CVD) being the most prevalent. The ability to simultaneously detect both biomarkers in point-of-care settings is in high demand for CVD early diagnosis and prevention. Herein, we prepared the eutectic gallium indium (EGaIn) nanoparticles decorated with p-phenylenediamine (PPD) on the surface to facilitate the subsequent attachment of gold nanoparticles (AuNPs) to achieve EGaIn-PPD@Au, which was modified on the screen-printed electrochemical paper-based analytical devices (ePADs). Aptamers that are specific to Hcy and CRP were then immobilized on the EGaIn-PPD@Au surface to achieve the sensing interface on ePADs. The presence of EGaIn-PPD@Au significantly enhanced the electrical conductivity, leading to amplified electrochemical signals. This aptasensor demonstrated high specificity, capable of detecting Hcy in a range of 1-50 μM with a detection limit of 0.22 μM, and the detection range for CRP was 1-100 ng/mL with a detection limit of 0.039 ng/mL. The aptasensor also effectively detected Hcy and CRP in clinical saliva samples, yielding an area under the curve (AUC) of about 0.80 when the individual biomarker was considered and 0.93 when both biomarkers were taken into account. The positive correlation observed between salivary and blood concentrations of Hcy and CRP, coupled with their association with cardiovascular disease (CVD), suggested the potential of this methodology as a noninvasive point-of-care strategy for the early diagnosis of CVD.

Innovation of nano-hydrogels loaded with amelogenin peptide and hydroxyapatite nano-particles for remineralisation of artificially induced white spot lesions

BackgroundWhite spot lesions are a common side effect of fixed orthodontics. This study investigates chitosan-based hydrogels using amelogenin peptide as a scaffold to facilitate hydroxyapatite nanoparticle attachment, assembly, and organisation, aiding in enamel remineralisation. Materials and methodsThree groups were prepared to carry out remineralisation experiments after creating artificial white spot lesions on extracted 1st premolars. The first group served as a control with no treatment, while the experimental groups were treated with either amelogenin peptide/chitosan hydrogel or amelogenin peptide + hydroxyapatite/chitosan hydrogel. Remineralisation was conducted for three weeks. The interaction between amelogenin peptide and hydroxyapatite nanoparticles was evaluated using TEM, UV–Vis, FTIR, zeta potential, and Raman spectroscopy. Remineralisation potential was assessed through enamel microhardness, fluorescence, and XRD. Surface characteristics of demineralised and remineralised enamel were examined by SEM at different magnifications, and chemical compositions were analysed using an EDX analyser. one-way ANOVA and Tukey HSD post hoc multi-comparison tests were performed to find statistical differences between groups. A pairwise comparison was performed to examine if there were significant differences within each group. Significant differences were considered at a P < 0.05. ResultsThe results demonstrated that amelogenin peptide adsorbs onto hydroxyapatite. TEM images revealed the self-assembly of peptide nanoparticles and their adsorption onto hydroxyapatite nanoparticles. UV–Vis spectroscopy, FTIR spectroscopy, Zeta Potential, and Raman Spectroscopy confirmed the binding between amelogenin peptide and hydroxyapatite. The novel hydrogel significantly improved the microhardness and fluorescence values of demineralised enamel. Energy-dispersive X-ray Spectroscopy and X-ray diffractometry revealed the formation of new hydroxyapatite crystals on demineralised enamel, with a calcium-to-phosphorus ratio comparable to natural enamel hydroxyapatite. Structural analysis via SEM showed improved surface texture with the occlusion of demineralised surface porosities. Overall, the hydrogel enhanced hardness, fluorescence, morphology, and chemical composition compared to demineralised enamel. ConclusionsChitosan-based hydrogels provide a promising remineralising strategy that bio-mimics natural enamel regrowth.

Determining the orderliness of carbon materials with nanoparticle imaging and explainable machine learning.

Carbon materials have paramount importance in various fields of materials science, from electronic devices to industrial catalysts. The properties of these materials are strongly related to the distribution of defects-irregularities in electron density on their surfaces. Different materials have various distributions and quantities of these defects, which can be imaged using a procedure that involves depositing palladium nanoparticles. The resulting scanning electron microscopy (SEM) images can be characterized by a key descriptor-the ordering of nanoparticle positions. This work presents a highly interpretable machine learning approach for distinguishing between materials with ordered and disordered arrangements of defects marked by nanoparticle attachment. The influence of the degree of ordering was experimentally evaluated on the example of catalysis via chemical reactions involving carbon-carbon bond formation. This represents an important step toward automated analysis of SEM images in materials science.