Effect Of Nanoparticles Research Articles

Comparative efficacy of Knema retusa extract delivery via PEG-b-PCL, niosome, and their combination against Acanthamoeba triangularis genotype T4: characterization, inhibition, anti-adhesion, and cytotoxic activity

Background Acanthamoeba spp. is a waterborne, opportunistic protozoan that can cause amebic keratitis and granulomatous amebic encephalitis. Knema retusa is a native tree in Malaysia, and its extracts possess a broad range of biological activities. Niosomes are non-ionic surfactant-based vesicle formations and suggest a future targeted drug delivery system. Copolymer micelle (poly(ethylene glycol)-block-poly(ɛ-caprolactone); PEG-b-PCL) is also a key constituent of niosome and supports high stability and drug efficacy. To establish Knema retusa extract (KRe) loading in diverse nanocarriers via niosome, PEG-b-PCL micelle, and their combination and to study the effect of all types of nanoparticles (NPs) on Acanthamoeba viability, adherent ability, elimination of adherence, and cytotoxicity. Methods In this study, we characterized niosomes, PEG-b-PCL, and their combination loaded with KRe and tested the effect of these NPs on Acanthamoeba triangularis stages. KRe-loaded PEG-b-PCL, KRe-loaded niosome, and KRe-loaded PEG-b-PCL plus niosome were synthesized and characterized regarding particle size and charge, yield, encapsulation efficiency (EE), and drug loading content (DLC). The effect of these KRe-loaded NPs on trophozoite and cystic forms of A. triangularis was assessed through assays of minimal inhibitory concentration (MIC), using trypan blue exclusion to determine the viability. The effect of KRe-loaded NPs was also determined on A. triangularis trophozoite for 24–72 h. Additionally, the anti-adhesion activity of the KRe-loaded niosome on trophozoites was also performed on a 96-well plate. Cytotoxicity activity of KRe-loaded NPs was assessed on VERO and HaCaT cells using MTT assay. Results KRe-loaded niosome demonstrated a higher yielded (87.93 ± 6.03%) at 286 nm UV-Vis detection and exhibited a larger size (199.3 ± 29.98 nm) and DLC (19.63 ± 1.84%) compared to KRe-loaded PEG-b-PCL (45.2 ± 10.07 nm and 2.15 ± 0.25%). The EE (%) of KRe-loaded niosome was 63.67 ± 4.04, which was significantly lower than that of the combination of PEG-b-PCL and niosome (79.67 ± 2.08). However, the particle charge of these NPs was similar (−28.2 ± 3.68 mV and −28.5 ± 4.88, respectively). Additionally, KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exhibited a lower MIC at 24 h (0.25 mg/mL), inhibiting 90–100% of Acanthamoeba trophozoites which lasted 72 h. KRe-loaded niosome affected adherence by around 40–60% at 0.125–0.25 mg/mL and removed Acanthamoeba adhesion on the surface by about 90% at 0.5 mg/mL. Cell viability of VERO and HaCaT cells treated with 0.125 mg/mL of KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exceeded 80%. Conclusion Indeed, niosome and niosome plus PEG-b-PCL were suitable nanocarrier-loaded KRe, and they had a greater nanoparticle property to test with high activities against A. triangularis on the reduction of adherence ability and demonstration of its low toxicity to VERO and HaCaT cells.

Development of a hybrid CuS-ICG polymeric photosensitive vector and its application in antibacterial photodynamic therapy.

At the present time, owing to the extremely high growth of microbial resistance to antibiotics and, consequently, the increased healthcare associated costs and the loss of efficacy of current treatments, the development of new therapies against bacteria is of paramount importance. For this reason, in this work, a hybrid synergetic nanovector has been developed, based on the encapsulation of a NIR (near infrared) photosensitive molecule (indocyanine green, ICG) in biodegradable polymeric nanoparticles (NPs). In addition, copper sulfide nanoparticles (CuS NPs), optically sensitive to NIR, were anchored on the polymeric nanoparticle shell in order to boost the generation of reactive oxygen species (ROS) upon NIR irradiation. As a result, the nanohybrid synthesized material is capable to generate ROS on demand when exposed to a NIR laser (808nm) allowing for the repeated triggering of ROS production upon NIR light exposure. After each irradiation, the ROS generated were able to eliminate pathogenic bacteria, as it was demonstrated in-vitro with three bacterial strains, Staphylococcus aureus ATCC 25923 used as a reference strain (S. aureus), S. aureus USA300 (methicillin-resistantstrain, MRSA) and GFP-expressing antibiotic-sensitive S. aureus (methicillin-sensitive strain, MSSA). Finally, the effect of the hybrid NPs in the skin bed was tested on a plasma-derived in vitro skin model. Fluorescence and histological images showed the presence of CuS NPs all over the dermal layer lacking epidermis of the skin construct. Thus, the in vitro model facilitated the prediction of the nanovector's behavior in a human skin equivalent, showcasing its potential application against topical infections after wounding.

Skin Sensitization Potential of Sensitizers in the Presence of Metal Oxide Nanoparticles In Vitro

Silica (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) nanoparticles (NPs) are widely used in dermal products. Their skin sensitization potential, especially their effects in combination with known sensitizers, is poorly studied in vitro and their sensitization inconsistently reported in animal studies. In this study, cellular assays were used to identify different steps of sensitization, the activation of keratinocytes and dendritic cells, when cells were exposed to these NPs in the absence and presence of sensitizers. Cellular systems included HaCaT keratinocytes and U937 (U-SENS™) alone, as well as different co-culture systems of THP-1 cells with HaCaT cells (COCAT) and with primary keratinocytes. The effect of NPs differed between co-cultures and U-SENS™, whereas co-cultures with either primary keratinocytes or HaCaT cells responded similarly. Pre-exposure to ZnO NPs increased the U-SENS™ assay response to 2,4-dinitrochlorobenzene six-fold. The COCAT increase was maximally four-fold for the combination of SiO2 and trans cinnamaldehyde. When the THP-1 cells were separated from the keratinocytes by a membrane, the response of the co-culture system was more similar to U-SENS™. The direct contact with keratinocytes decreased the modulating effect of TiO2 and ZnO NPs but suggested an increase in response to sensitizers following dermal contact with SiO2 NPs.

Impact of TiO2, ZnO, and Ag nanoparticles on anammox activity in enriched river Nile sediment cultures: unveiling differential effects and environmental implications.

The increasing use of nanoparticles (NPs) necessitates investigation of their impact on wastewater treatment processes, particularly anammox, a critical biological nitrogen removal pathway. This study explored the effects of short-term exposure to TiO2, ZnO, and Ag-NPs on anammox activity in enriched cultures derived from River Nile sediments. Anammox bacteria were identified and enriched, with activity confirmed through 16S rRNA and hydrazine oxidoreductase (hzo) gene amplification and sequencing. Activity assays demonstrated efficient ammonium removal by the enriched culture. Subsequently, the impact of different sized and concentrated NPs on anammox activity was assessed. XRD analysis confirmed NP behavior within the microcosms: TiO2 transformed, ZnO partially dissolved, and Ag remained ionic. hzo gene expression served as a biomarker for anammox bacterial activity. Interestingly, 100nm TiO2-NPs up-regulated hzo expression, potentially indicating a non-inhibitory transformed phase. Conversely, ZnO and Ag-NPs across all sizes and concentrations significantly down-regulated hzo expression, suggesting detrimental effects. Ag-NPs amended microcosms showed a significant reduction (79%) in hzo gene expression and a detrimental effect on bacterial populations. Overall, anammox activity mirrored hzo expression patterns, with TiO2 (21 and 25nm, respectively) exhibiting the least inhibition, followed by ZnO and Ag-NPs. This study highlights the differential effects of NPs on anammox, with the order of impact being Ag > ZnO > TiO2. These findings provide valuable insights into the potential environmental risks of NPs on anammox-mediated nitrogen cycling in freshwater ecosystems.

Quantitative cytotoxicity analysis of antibacterial Janus nanoparticles in immune and cancer cells

Background Nanoparticles (NPs) hold promise as alternatives to antibiotics in the fight against multi-drug-resistant bacteria. However, concerns about their cytotoxicity, particularly their effects on mammalian cells, must be thoroughly addressed to ensure therapeutic safety. Amphiphilic Janus NPs, which have segregated hydrophobic and polycationic ligands on two hemispheres, have previously been shown to exhibit potent antibacterial activity. Methods In this study, we evaluated the cytotoxicity of amphiphilic Janus NPs in immune and cancer cell lines. Cytotoxicity assays were performed to assess the effects of Janus NPs on cell viability and membrane integrity, with a particular focus on how internalization of the nanoparticles influenced cellular responses. Results The results revealed that both immune and cancer cells exhibited negligible cytotoxic effects when exposed to Janus NPs. However, phagocytic immune cells demonstrated greater susceptibility to membrane damage and viability loss, suggesting that internalization plays a significant role in nanoparticle-induced cytotoxicity. Conclusions Amphiphilic Janus NPs show great potential as highly effective antibacterial agents with minimal cytotoxicity. While immune cells may be more vulnerable to nanoparticle-induced damage due to their internalization capacity, these findings support the further investigation of Janus NPs for clinical applications.

A Facile Microwave-Promoted Formation of Highly Photoresponsive Au-Decorated TiO2 Nanorods for the Enhanced Photo-Degradation of Methylene Blue

The integration of noble metal nanoparticles (NPs) effectively modifies the electronic properties of semiconductor photocatalysts, leading to improved charge separation and enhanced photocatalytic performance. TiO2 nanorods decorated with Au NPs were successfully synthesized using a cost-effective, rapid microwave-assisted method in H2O2 and HF media for methylene blue (MB) degradation under visible light illumination. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 physisorption, and UV–vis spectroscopy were employed to characterize the structures, morphologies, compositions, and photoelectronic properties of the as-synthesized materials. The fusing of Au NPs effectively alters the electronic structure of TiO2, enhancing the charge separation efficiency and improved electrical conductivity. The HF treatment promotes the exposure of the highly reactive (001) and (101) crystalline facets. The improved photocatalytic activity of Au/TiO2, achieving 97% efficiency, is attributed to the surface plasmon resonance (SPR) effect of the Au NPs and the presence of oxygen vacancies. The photodegradation of MB using the TiO2/Au photocatalysts follows pseudo-first-order kinetics, highlighting the enhanced catalytic efficiency of the synthesized nanostructures. The exceptional properties of the binary Au/TiO2 photocatalysts, including the SPR effect, exposed crystallographic faces, and efficient charge carrier separation through a decrease in the recombination of electrons and holes, contribute to the photocatalytic degradation of MB.

Investigation of the synergistic effects of SiO2 and Al2O3 nanoparticles with SDS and CTAB surfactants on the stability and improving phase behavior of water-oil emulsions

The stability of emulsions is a significant challenge across various industries, including food, pharmaceutical, and petroleum. Surface-active agents utilized for enhanced oil recovery often exhibit inadequate performance under high salinity reservoir conditions, presenting a critical barrier to effective emulsion stabilization. Furthermore, due to the extreme hydrophilic or hydrophobic nature of nanoparticles (NPs), they are not effective in stabilizing emulsions on their own. To address this limitation, a minimal quantity of surfactant was introduced into the NPs to improve their wettability and achieve dual wettability. This research has examined the synergistic effects of SiO₂ and Al₂O₃ NPs combined with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) surfactants on water-oil emulsion stability. This approach enhanced emulsion stability by combining the stabilizing effects of both the NPs and the surfactants, an aspect that has not been previously addressed in phase behavior studies through the examination of the interactions and surface behavior of surfactant-nanoparticle complexes at the oil-water interface. Several experiments, including phase behavior, FT-IR, zeta potential, contact angle, and interfacial tension (IFT) tests, were performed to evaluate the interaction of surfactants with NPs. The results demonstrate that combining NPs with surfactants, especially those with opposite charges, significantly reduces IFT to the order of 10−6 mN/m, which can overcome capillary pressure, and enhances optimal salinity levels even up to 75000 ppm. Interactions between CTAB-SiO₂ and SDS-Al₂O₃ notably improve the hydrophobicity of NPs, resulting in IFT reductions of 11.4 and 7 mN/m, respectively, compared to NPs alone.

Fabrication of Luminescent Titanium Dioxide Nanoparticles in a Biocompatible Approach: Its Potential for Photodecomposition and Germicidal Effects.

The fabrication of the green strategy of metallic oxide creation provides considerable profits via a minimum of effort, making it an acceptable substitute to the most laborious and challenging conventional processes. The suggested approach involved the creation of titanium dioxide (TiO2) nanoparticles through Orthosiphon stamineus extracts of leaves. The synthesized nanoparticles (NPs) were then characterized using XRD, FT-IR, FE-SEM with EDX, and UV-visible spectroscopy. UV-visible spectroscopy validated the presence of optical imperfections in the TiO2 NPs at frequencies of 286 nm. This research specifically focused on examining the photodecomposition and germicidal traits of NPs. Initiatives aimed must be made to mitigate the hazardous effects of TiO2 NPs in an ecologically sensitive way throughout their production. Exposing the dye methylene blue (MB), a major water polluting produced by garment manufacturing, to TiO2 NPs resulted in a considerable increase in photodecomposition efficiency. The photodecomposition process exhibited a rate of breakdown of 83%. The findings indicate that the diameter inhibition zone exhibits the most potent resistance versus pathogenic microorganisms. These results have led to the identification of a long-term, sustainable, and ecologically beneficial solution for removing pollutants from water and biological properties.

A numerical study of the effect of graphene nanoparticle size on brownian displacement, thermophoresis, and thermal performance of graphene/water nanofluid by molecular dynamics simulation

Brownian motion, often known as BM, is an inherent characteristic of minute particles suspended in a fluid. It plays an important role in several physical and chemical processes. Thermophoresis refers to the process where particles in a fluid are carried along with a gradient in temperature (Temp). This feature has significant importance in several applications, including microfluidics, thermal control, and energy conversion. Through the examination of the thermophoresis phenomenon in water/graphene nanofluid (NF), researchers might get valuable knowledge on the potential uses of these materials. The current study examined the effect of various sizes of graphene nanoparticles (NPs) (5, 6, 9, and 10 Å) on the thermal behavior (TB), BM, and thermophoresis of water/graphene NF using molecular dynamics (MD) simulation. This study reported the changes in heat flux (HF), thermal conductivity (TC), average Brownian displacement (BD), and thermophoresis. It is concluded that by increasing the size of graphene NPs from 5 to 10 Å, the average BD and thermophoresis increased from 3.06 Å and 23.88 Å to 4.16 Å and 31.46 Å, respectively. Due to their higher kinetic energy (KE) and momentum, larger graphene NPs experienced more BM, enabling them to withstand random thermal fluctuations more effectively than smaller particles. In addition, as the size of graphene NPs increased, the HF and TC values ​​increased from 39.54 W/m2 and 0.36 W/(m.K) to 47.19 W/m2 and 0.51 W/(m.K) after 10 ns. Therefore, the size-dependent changes in BD and thermophoretic effects led to a simultaneous increase in HF and TC of the NF, which was attributed to the larger heat transfer (HT) surface area, improved HT properties, and synergistic effects of larger graphene NPs. The maximum (Max) temperature increases from 1415 K to 1504 K. These findings were useful in a variety of industries, particularly for improving TB in different NFs.

Loss of HIV candidate vaccine efficacy in male macaques by mucosal nanoparticle immunization rescued by V2-specific response

Systemic vaccination of macaques with V1-deleted (ΔV1) envelope immunogens reduce the risk of SIVmac251 acquisition by approximately 60%, with protective roles played by V2-specific ADCC and envelope-specific mucosal IL-17+NKp44+ innate lymphoid cells (ILCs). We investigated whether increased mucosal responses to V2 benefit vaccine efficacy by delivering oral nanoparticles (NPs) that release V2-scaffolded on Typhoid Toxin B (TTB) to the large intestine. Strikingly, mucosal immunization of male macaques abrogated vaccine efficacy with control TTB or empty NPs, but vaccine efficacy of up to 47.6% was preserved with V2-TTB NPs. The deleterious effects of NPs were linked to preferential recruitment of mucosal plasmacytoid dendritic cells (pDCs), reduction of protective mucosal NKp44+ ILCs, increased non-protective mucosal PMA/Ionomycin-induced IFN-γ+NKG2A-NKp44-ILCs, and increased levels of mucosal activated Ki67+CD4+ T cells, a potential target for virus infection. V2-TTB NP mucosal boosting rescued vaccine efficacy, likely via high avidity V2-specific antibodies mediating ADCC, and higher frequencies of mucosal NKp44+ ILCs and of ∆V1gp120 binding antibody-secreting B cells in the rectal mucosa. These findings emphasize the central role of systemic immunization and mucosal V2-specific antibodies in the protection afforded by ΔV1 envelope immunogens and encourage careful evaluation of vaccine delivery platforms to avoid inducing immune responses favorable to HIV transmission.

Influence of Foliar Application of Nanoparticles on Low Temperature Resistance of Rice Seedlings.

Chilling stress, a common abiotic factor, adversely affects the growth and biomass of rice seedlings during the early stages, ultimately reducing the yield. Effective strategies to mitigate these negative impacts are essential for improving rice productivity. The application of nanotechnology in agriculture, particularly nanoparticles (NPs), has shown a promising effect in alleviating chilling stress in plants. This study evaluates the effects of various nanoparticles, ZnO (0, 50, 100, and 200 mg/L), Fe2O3 (0, 50, 75, and 100 mg/L), TiO2 (0, 50, 75, and 100 mg/L), and CeO2 (0, 50, 75, and 100 mg/L) on the chilling resistance with one control (a water spray) under a normal temperature. Four rice cultivars: LLY-7108 and XZX-6 (Low-temperature-tolerant), and LLY-32 and ZJZ-17 (Low-temperature-susceptible) were tested in this experiment. Rice seedlings were subjected to low temperature conditions (12 h light 14 °C/12 h dark, at 10 °C) for five days, followed by seven days of recovery. The results of this study demonstrate that NPs significantly enhanced seedling height fresh/dry weight and root length compared to untreated controls under chilling stress. NP treatment also reduced the reactive oxygen species (ROS), malondialdehyde (MDA), and proline content, while enhancing superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, thereby mitigating oxidative damage. The four rice varieties exhibited clear signs of rapid growth recovery and positive physiological changes due to NPs' application. Among the tested cultivars, LLY-7108 showed the most substantial recovery and physiological responses, while ZJZ-17 exhibited the least. The findings of this study indicate that the foliar application of ZnO (100 mg/L), Fe2O3 (50 mg/L), TiO2 (50 mg/L), and CeO2 (75 mg/L) NPs effectively mitigates chilling stress in rice seedlings, likely by enhancing the antioxidant enzymatic activity while reducing the oxidative damage. This study highlights the potential of NPs as effective agents in reducing the adverse effects of chilling stress on rice.

Optimising Nanoparticle Dispersion Time for Enhanced Thermomechanical Properties in DGEBA-Based Shape Memory Polymer Composites

Shape-memory polymers (SMPs) are smart materials that can change shape upon an external stimulus. This phenomenon is called the shape memory effect (SME), which is caused by entropy change due to rapid molecular motion in the polymer segments. Due to the inherently weak thermomechanical properties, use of SMPs is limited in many engineering applications. Therefore, SMPs are often reinforced with fibres and nanoparticles (NPs). NPs offered greater flexibility due to their superior physical, chemical, electrical, mechanical, and thermal properties. However, the homogeneous distribution of NPs is crucial for composition’s stability and enhancement of the base material’s properties. Among the different techniques used for dispersing NPs, ultrasonic irradiation has shown excellent emulsifying and crushing performance. The sonication process is essential for mitigating agglomerates; however, prolonged sonication time probably increases epoxy temperature, micro-bubbles, cavitation, breaking apart molecules and finally degrading the epoxy resin performances. This paper provides critical insight of nanoparticle dispersion into diglycidyl ether of bisphenol A epoxies (DGEBA). DGEBA epoxy resin was added to TiO2 NPs and sonicated for 60 min with 5 min intervals while the temperature of epoxy was maintained below 60oC by using a water cooling throughout the sonication process. The process parameters such as amplitude, mode, epoxy volume and the weight percentage of NPs were kept constant. After each sonication step, Fourier-transform infrared spectroscopy (FTIR) was performed using Thermo Scientific™ and analysed through OMNIC™ Professional quantitation software. In accordance with FTIR results, until 30 min of the sonication, DGEBA resin was not degraded. In order to confirm the performances and the reinforcing effect of NPs, thermo-mechanical and shape memory properties were compared with the neat specimen. The outcomes of this research have suggested quick guidance to find optimum NP dispersion time for DGEBA resins, which has been hardly studied before.

Emerging Promise of Green Synthesized Metallic Nanoparticles for the Management of Neurological Disorders.

The management of neurological disorders is very challenging due to the presence of the bloodbrain barrier (BBB) that prevents the entry of drugs into the central nervous system (CNS). The advancement of metallic nanoparticles (NPs) provides a novel direction for the treatment of neurological disorders. However, there is a significant concern regarding the toxic effects of metal NPs on biological tissues like the brain. The green synthesis strategy offers a superior alternative to the traditional methods for the development of metallic NPs. Notable metal and metal oxide NPs can be produced using various bio-reductants derived from natural sources such as plant tissues, fungi, bacteria, yeast, and alga. These biological agents play double roles as they expedite the reduction process and act as capping and stabilizing agents. In this paper, we discuss the major neurological disorders and the physical barriers limiting the transport of therapeutics to the CNS. Moreover, a special focus is given to the unique features of green synthesized metallic NPs for therapeutic purposes in various neurological disorders. The insights provided will guide future research toward better outcomes and facilitate the development of innovative treatments for neurological disorders.

Investigations on the complexation and binding mechanism of bovine serum albumin with Ag-doped TiO2 nanoparticles.

It is essential to study the interactions between nanoparticles and proteins to better understand the biological interactions of nanoparticles. In this study, we studied the protein adsorption mode on the surface of Ag-doped TiO2 nanoparticles (NPs) using a model protein, bovine serum albumin (BSA). The mechanism of binding BSA to the Ag-doped TiO2 NPs was studied by applying fluorescence quenching, absorbance measurements, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy techniques. The strong binding between BSA and Ag-doped TiO2 NPs was confirmed by a high value of binding constant (K = 2.65 × 105 L mol-1). We also studied the thermal stability of BSA in the presence of the Ag-doped TiO2 NPs. Thermodynamic parameters indicated that the adsorption of BSA on the Ag-doped TiO2 NPs was a spontaneous, natural and exothermic process. The effect of Ag-doped TiO2 NPs on the transportation function of BSA was also studied using a fluorescence spectroscopic technique. Fluorescence spectroscopic data suggested the existence of a strong interaction between BSA and the surface of the Ag-doped TiO2 NPs, which indicated that the binding affinities of some selected amino acids in BSA changed. This, in turn, clearly confirms that the Ag-doped TiO2 NPs affect the transportation capability of BSA in blood.

Au@Pt nanoparticles-based signal-enhanced lateral flow immunoassay for ultrasensitive naked-eye detection of SARS-CoV-2.

With SARS-CoV-2 N protein as a model target, a signal-enhanced LFIA based on Au@Pt nanoparticles (NPs) as labelsis proposed. This Au@Pt NPs combined the distinguished localized surface plasma resonance (LSPR) effect of Au NPs and the ultrahigh peroxidase-like catalytic activity of Pt NPs. Au@Pt NPs could trigger substrate chromogenic reaction, generating acolor signal orders of magnitude darker than their intrinsic color. In the detection, after the coloration of the strips, 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 were added, and adark blue chelate (OxTMB) was produced soon, enhancing the band color significantly. After the signal amplification, the naked-eye detection limit for N protein reached 40pg/mL. The detection sensitivity enhanced more than 1000 times than that without signal amplification. Compared with mainstream LFIA requiring complex readout instruments, theAu@Pt-based LFIA achieved a comparable sensitivity usingnaked eyesdetection. This point is crucial, especially for unprofessional users or low-resource areas. Hence, this signal-enhanced LFIA may serve as a sensitive, cost-effective, and user-friendly detection method. It can shorten the testing window period and help identify early infections.

Algorithm development and metal oxide nanoparticle analysis in magnetic resonance imaging: Advancing neurodegenerative disease diagnostics

Magnetic resonance imaging (MRI) is critical in the diagnosis of neurodegenerative diseases, enabling the detection of brain lesions. Recent research has examined metallic nanoparticles (NPs) as MRI contrast agents (CAs) that can enhance lesion visibility by altering relaxation times. This study investigates the effects of metal oxide NPs on MRI relaxation times and brain lesion signals and proposes an algorithm for automated relaxation time determination using these NPs. The utilized NPs were synthesized using the sol‒gel method and characterized using Fourier-transform infrared spectroscopy and X-ray diffraction. MRI scans were performed on a phantom infused with varying concentrations of each metal oxide NP to assess changes in pixel signal intensities and relaxation rates. Our analysis involved segmenting the MRI images to focus on regions with different NP concentrations. The algorithm computed the longitudinal relaxation time for each region, revealing that Fe2O3 NPs exhibited the most substantial effect on signal intensity and relaxation time. The results indicated a high correlation (r = 0.9977), demonstrating strong agreement and confirming the reliability of our method. Our findings suggest that metallic oxide NPs, particularly Fe2O3, can considerably alter magnetization and act as effective negative CAs in MRI. These capabilities can improve the monitoring and treatment efficacy of neurodegenerative diseases. Our method for quantifying longitudinal relaxation times can potentially enhance routine clinical MRI assessments, offering a promising tool for future clinical applications.

Effect of pure (ligand-free) nanoparticles of magnetite in sodium chloride matrix on hematological indicators, blood gases, electrolytes and serum iron

AbstractOne of the physical methods for obtaining magnetite nanoparticles (NPs) is electron beam physical vapor deposition (EB PVD), which requires complex equipment, but allows obtaining a significant amount of pure (ligand-free) NPs. The biomedical application of such NPs is less studied than materials from other synthesis methods. The objective is to study the effect of pure magnetite NPs in the NaCl matrix obtained by EB PVD on hematological indicators, gases, electrolytes and parameters of iron metabolism in the blood of intact animals. The physical characteristics of NPs were studied using high-resolution transmission electron microscopy, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy mapping, electron energy-loss spectroscopy, selected area electron diffraction and fast Fourier transform. In vivo experiments were conducted on albino male rats, which were injected with solution of magnetite-sodium chloride NPs (1.35 mg Fe/kg). After 3 and 72 h, hematological parameters, blood gases, electrolytes, and serum iron were determined. The synthesized NPs had an average size of 11 nm. They were identified as magnetite, where polycrystals and single crystals were present. The absence of contamination in crystal boundaries, clear orientation and orderliness of atoms in crystals were established. The administration of NPs in the sodium chloride matrix to animals was characterized by a transient increase in the main indicators of red blood accompanied by an increase in the saturation of erythrocytes with hemoglobin and their mean volume after 3 h. It did not worsen blood gases and pH, but decreased blood Na+ content after 72 h. The investigated NPs caused changes in the parameters of serum iron characteristic to iron preparations, which after 3 h were smaller compared to the reference iron drug, and after 72 h—similar to it. More intense rapid effects on hematological parameters at lower serum iron indicate greater activity of the studied pure magnetite NPs obtained by EB PVD syntesis compared to the reference iron preparation.

Molten Salt-Assisted Synthesis of Ferric Oxide/M-N-C Nanosheet Electrocatalysts for Efficient Oxygen Reduction Reaction.

Efficient, stable, and low-cost oxygen reduction catalysts are the key to the large-scale application of metal-air batteries. Herein, high-dispersive Fe2O3 nanoparticles (NPs) with abundant oxygen vacancies uniformly are anchored on lignin-derived metal-nitrogen-carbon (M-N-C) hierarchical porous nanosheets as efficient oxygen reduction reaction (ORR) catalysts (Fe2O3/M-N-C, M═Cu, Mn, W, Mo) based on a general and economical KCl molten salt-assisted method. The combination of Fe with the highly electronegative O induces charge redistribution through the Fe-O-M structure, thereby reducing the adsorption energy of oxygen-containing substances. The coupling effect of Fe2O3 NPs with M-N-C expedites the catalytic activity toward ORR by promoting proton generation on Fe2O3 and transfer to M-N-C. Experimental and theoretical calculation further revealed the remarkable electronic structure evolution of the metal site during the ORR process, where the emission density and local magnetic moment of the metal atoms change continuously throughout their reaction. The unique layered porous structure and highly active M-N4 sites resulted in the excellent ORR activity of Fe2O3/Cu-N-C with the onset potential of 0.977V, which is superior to Pt/C. This study offers a feasible strategy for the preparation of non-noble metal catalysts and provides a new comprehension of the catalytic mechanism of M-N-C catalysts.

Size-Dependent Core-Shell Fine Structures and Oxygen Evolution Activity of Electrochemical IrOx Nanoparticles Revealed by Cryogenic Electron Microscopy.

Electrochemically oxidized amorphous iridium oxides (IrOx) offer significantly improved electrocatalytic activities on the oxygen evolution reaction (OER) compared to crystalline IrO2, yet the origin of their decent activity and their size-dependent properties have not been fully understood. An important argument is the formation of deprotonated oxygen species not only at the topmost surface but also at the near surface, which creates an electrophilic character that activates the OER electrocatalysis. However, high spatial resolution identification of the electrophilic oxygen species remains unachieved. We address this hitherto-unresolved problem on size-selected electrochemical IrOx nanoparticles (NPs) by using cryogenic scanning transmission electron microscopy combined with electron energy loss spectroscopy, which enables simultaneous atomic detection of the near surface compositional and electronic structures with minimal damage that are further correlated with their size-dependent OER activities. Depending on the particle size, the electrochemical IrOx NPs showed distinctly different core-shell fine structures ranging from amorphous and hydrous IrOxHy NPs to a "metallic Ir core/sub-stoichiometric IrOx interlayer/amorphous IrOxHy shell" NP structure. Moreover, the formation of deprotonated, electrophilic oxygen is directly identified at the substoichiometric IrOx interface layer. These features account for a previously unestablished particle size effect of the electrochemical IrOx NPs, showing increasing water oxidation reactivity with an increasing nanoparticle size. Our results provide important insights into how subsurface oxygen chemistry controls the surface reactivity in the nanoscale Ir-based OER electrocatalysts.

Circadian Rhythm-Dependent Therapy by Composite Targeted Polyphenol Nanoparticles for Myocardial Ischemia-Reperfusion Injury.

Myocardial ischemia-reperfusion (IR) injury is a severe rhythmic disease with a high prevalence in the early morning. IR injury has a significant circadian rhythm in reactive oxygen species (ROS) and inflammation levels. The development of rhythmic drugs has become a priority in myocardial IR injury. In this study, resveratrol (RES) and proanthocyanidins (OPC) were utilized to design nanoparticles (NPs), with hyaluronic acid (HA) as the core, grafted with MMP-targeting peptides to improve delivery to injured myocardial regions (HA-RES-OPC-MMP NPs). NPs significantly scavenged ROS, attenuated inflammation, and activated the rhythm gene. Notably, the difference in therapeutic effects on myocardial IR injury in mice at Zeitgeber time (ZT)1 and ZT13 confirms that NPs are rhythm-dependent drugs. At ZT13, echocardiographic and MRI confirm that IR injury in mice was not as severe as at ZT1, yet NPs were also less effective in treatment. Further, Per1/2 knockout mice confirmed the rhythm-dependent treatment of myocardial IR injury by NPs. Molecular studies have shown that rhythmic characteristics of inflammation and Sirt1 transcript levels are the main reasons for the different rhythmic therapeutic effects of NPs. Circadian rhythm-dependent treatment of HA-RES-OPC-MMP NPs has excellent potential for more precise treatment of myocardial IR injury in the future.