Size Of Nanoparticles Research Articles

Realizing the strength-ductility balance of a warm-rolled 10 Mn steel via preparing dual nano-sized precipitates

A novel strategy involving warm rolling and tempering-annealing was introduced to optimize the strength-ductility balance of Fe-10.2Mn-2.2Al-0.41C-0.6 V (wt. %) steel. The V- and κ-carbide particles produced during the tempering are critical for tailoring the austenite characteristics during the subsequent annealing. Austenite that nucleates on Mn-rich κ-carbides inherit their high Mn content and fine grain size. Quantitative calculations suggest that the pinning effect exerted by the V-carbide particles strongly resists grain boundary motion and recrystallization grain growth, further refining the final microstructure. Moreover, the dual nano-sized particles induce abnormal variations in the grain size and fraction of austenite, influencing the deformation mechanisms. In the absence of deformation twins, the fresh martensite develops into “separating walls” to refine the microstructure and further enhances the work hardening in addition to the complex dislocation mobile. Finally, the tempered-annealed sample demonstrated a simultaneous increase in the yield and tensile strengths from 1166 to 1452 MPa and 1507–1727 MPa, but a slight decrease in the total elongation from 18.6% to 16.8% compared to annealed sample, achieving a good strength-ductility balance.

Graphene powders as new contact nanopesticides: Revealing key parameters on their insecticidal activity for stored product insects

The overuse and reliance on pesticides has caused insects to develop resistance with global concerns. To address this problem extensive research is directed to find new and sustainable alternatives using chemical-free and resistance-free solutions for pest control. This paper presents a comprehensive investigation of the insecticidal properties of several types of industrially produced graphene powder materials such as graphene and graphene oxide (GO) with micro- and nano size and different structural and chemical properties as new contact nanopesticides against three major stored grain insects: the rice weevil Sitophilus oryzae (L.), the lesser grain borer, Rhyzopertha dominica (F.)˙ and the larger grain borer, Prostephanus truncatus Horn. Bioassays were performed using different concentrations, i.e., 0, 100, 500 and 1000 ppm of graphene powders on the mortality of selected adult insects recorded after 3, 7, 14, and 21 days of exposure and progeny production after 65 days. Results showed that graphene oxide (GO) has no insecticidal efficacy while graphene powders with nano-size particles showed significantly enhanced insecticidal performance compared to micron-size graphene powders. The observed insecticidal effects are explained by the higher probability that nano-sized graphene particles adhere on the insect body compared to large particles. The mortality is proposed as the result of physical mode of action of attached graphene nanoparticles causing stronger interruption of the protective cuticle layer, gas respiratory functions and faster mortality. The findings of this study revealed that it is important to select graphene materials with optimal structural and interfacial properties to achieve the highest insecticidal performance in potential development of a new generation of sustainable insecticides.

Size-dependent activity modulation of supported Ni nanocatalysts for efficient solid-state hydrogen storage in magnesium

The activity of Nickel (Ni)-based catalysts strongly depends on their particle size and dispersion; however, achieving controllable preparation of uniform particle size with high activity remains a great challenge for Ni-based catalysts to promote efficient hydrogen storage. Here, we employ a facile Carbothermal Shock (CTS) method to obtain carbon fiber-loaded Ni-based nanocatalysts (Ni@CC) with high dispersibility and size-dependent properties, which can exhibit superior catalytic effects for solid-state hydrogen storage in MgH2. It was found that the shorter the CTS duration, the smaller the size of the Ni nanoparticles, and the better the catalytic effect. Among these, the MgH2-Ni@CC with a CTS duration of 30 s showed the best hydrogen storage performance. Its activation energy for hydrogen release was significantly decreased from 158.3 kJ⋅mol−1 for milled MgH2 to 98.6 kJ⋅mol−1. More importantly, the retention rate of hydrogen absorption capacity is 95.1 % after 30 cycles, which far exceeds the 65.5 % retention rate observed in milled MgH2. These property enhancements can be attributed to the presence of nano-sized Ni and its in situ derived Mg2Ni intermediate phases, which create more channels for hydrogen atoms diffusion. Meanwhile, the close contact between nano-Ni and the Mg/MgH2 matrix can provide active catalytic sites and low-energy interfaces for facilitating hydrogen adsorption and desorption. Our study presents a promising approach to significantly improve the hydrogen storage performance of MgH2 by modulating size-dependent catalytic activity.

Tunable Nanoislands Decorated Tapered Optical Fibers Reveal Concurrent Contributions in Through-Fiber SERS Detection.

Creating plasmonic nanoparticles on a tapered optical fiber (TF) tip enables a remote surface-enhanced Raman scattering (SERS) sensing probe, ideal for challenging sampling scenarios like biological tissues, site-specific cells, on-site environmental monitoring, and deep brain structures. However, nanoparticle patterns fabricated from current bottom-up methods are mostly random, making geometry control difficult. Uneven statistical distribution, clustering, and multilayer deposition introduce uncertainty in correlating device performance with morphology. Ultimately, this limits the design of the best-performance remote SERS sensing probe. Here we employ a tunable solid-state dewetting method to create densely packed monolayer Au nanoislands with varied geometric parameters in direct contact with the silica TF surface. These patterns exhibit analyzable nanoparticle sizes, densities, and uniform distribution across the entire taper surface, enabling a systematic investigation of particle size, density, and analyte effects on the SERS performance of the through-fiber detection system. The study is focused on the SERS response of a widely employed benchmark molecule, rhodamine 6G (R6G), and serotonin, a highly relevant neurotransmitter for the neuroscience field. The numerical simulations and limit of detection (LOD) experiments on R6G show that the increase of the total near-field enhancement volume promotes the SERS sensitivity of the probe. However, we observed a different behavior for serotonin linked to its interaction with the nanoparticle's surface. The obtained LOD is as low as 10-7 M, a value not achieved so far in a through-fiber detection scheme. Therefore, our work offers a strategy to design nanoparticle-based remote SERS sensing probes and provides new clues to discover and understand intricate plasmonic-driven chemical reactions.

Characterization of Nanoparticles in Drinking Water Using Field-Flow Fractionation Coupled with Multi-Angle Light Scattering and Inductively Coupled Plasma Mass Spectrometry

The current absence of well-established and standardized methods for characterizing submicrometer- and nano-sized particles in water samples presents a significant analytical challenge. With the increasing utilization of nanomaterials, the potential for unintended exposure escalates. The widespread and persistent pollution of water by micro- and nanoplastics globally is a concern that demands attention, not only to reduce pollution but also to develop methods for analyzing these pollutants. Additionally, the analysis of naturally occurring nano entities such as bubbles and colloidal matter poses challenges due to the lack of systematic and consistent methodologies. This study presents Asymmetric Flow Field-Flow Fractionation (AF4) separation coupled with a UV-VIS spectrometer followed by Multi-Angle Light Scattering (MALS) for detection and size characterization of nanometric entities. It is coupled with an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) for elemental analysis. Water samples from different sources, such as untreated mountain spring water, groundwater, and bottled drinking water, were analyzed. The system was calibrated using pure particle standards of different metallic compositions. Our study demonstrates the capability of AF4-UV-MALS-ICP-MS to detect metals such as Al, Ba, Cu, and Zn in particles of around 200 nm diameter and Mg associated with very small particles between 1.5 and 10 nm in different drinking water samples.

Production of Biopolymeric Microparticles to Improve Cannabigerol Bioavailability.

Cannabigerol's (CBG) therapeutic effects are limited by its poor water solubility and low dissolution rate. To improve these properties, supercritical CO2-assisted atomization (SAA) was applied to produce coprecipitates, i.e., CBG nanoparticles coprecipitated in polyvinylpyrrolidone (PVP) microparticles. The experiments were performed by varying the CBG/PVP mass ratio (R) and the overall concentration of solutes CBG+PVP to study the influence of these parameters on particle morphology, particle size, and size distribution. Periodic dynamic light scattering (DLS) analysis was performed at regular time intervals to measure the size of CBG nanoparticles in PVP microparticles. It showed that CBG nanoparticles down to 105 nm were successfully produced through SAA. Dissolution tests were used to verify that a reduction of CBG particle size significantly increased its dissolution rate. In the liquid medium adopted, untreated CBG powder was released in 210 min, whereas CBG nanoparticles of 105 nm were completely dissolved in only 15 min.

Highly operative removal of amoxicillin (AMX) from aqueous solution by MnFe2O4 nanoparticles and carboxy methyl cellulose (CMC) composite

In recent work, manganese ferrite (MnFe2O4) nanoparticles and manganese ferrite carboxy methyl cellulose (MnFe2O4/CMC) composite were synthesized using Salvadora persica extract (SPE). Characterization of green synthesized nanoparticles and composite was performed by different techniques such as FTIR, SEM, UV–visible spectroscopy, XRD, and EDX. These techniques evaluated the size, shape, composition, morphology, and crystallinity of bimetallic nanoparticles (BMNPs) and nano-composites (NCs). These techniques demonstrated the presence of oxygen with metals, 3.28 nm size of MnFe2O4 and CMC hump between the 22-26° and the spherical, cubic, and mostly irregular shape of MnFe2O4 nanoparticles and rougher surface of MnFe2O4/CMC composite. Nanoparticles and nanocomposites were utilized for the degradation of Amoxicillin (AMX). The maximum degradation of AMX occurred at optimum conditions such as adsorbent dosage (6 mg MnFe2O4, 2 mg MnFe2O4/CMC), pH (4,6) within 60 min at 5 mg/L initial AMX concentration. Results revealed that the catalytic activity of NCs (97 %) was more than BMNPs (93 %) which may be attributed to the incorporation of reduced Carboxy Methyl Cellulose (CMC). It reduced the e-hole recombination rate and enhanced the AMX degradation at ambient conditions. The nature of adsorption was illustrated by Langmuir and Freundlich models and results demonstrated that the Freundlich model followed more closely. Thermodynamics parameters described the endothermic and spontaneous nature of the adsorption process, negative Gibbs energy variation, and positive entropy and enthalpy change. The recovery and reusability of BMNPs and NCs were investigated and concluded that MnFe2O4 and NCs can be used many times for the AMX adsorption process.

Nanoparticle Diffusion in Crowded Polymer Nanocomposite Melts.

This study examines nanoparticle diffusion in crowded polymer nanocomposites by diffusing small Al2O3 nanoparticles (NPs) in SiO2-loaded P2VP matrices. Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) measures Al2O3 NP diffusion coefficients within a homogeneous PNC background of larger, immobile SiO2 NPs. By developing a geometric model for the average interparticle distance in a system with two NP sizes, we quantify nanocomposite confinement relative to the Al2O3 NP size with a bound layer. At low SiO2 concentrations, Al2O3 NP diffusion aligns with the neat polymer results. In more crowded nanocomposites with higher SiO2 concentrations where the interparticle distance approaches the size of the mobile Al2O3 NP, the 6.5 nm Al2O3 NPs diffuse faster than predicted by both core-shell and vehicular diffusion models. Relative to our previous studies of NPs diffusing into polymers, these findings demonstrate that the local environment in crowded systems significantly complicates NP diffusion behavior and the bound layer lifetimes.

Enhancing capture efficiency of drug-carrier particles in the carotid sinus by utilizing a combination of magnetic fields: A numerical approach

Magnetic drug targeting is a relatively new method to treat vascular occlusion in different body parts. However, the effectiveness of this method can be affected due to the severity and location of the occlusion. This can lead to the injection of high dosages of drugs, which can cause serious side effects due to the deposition of drugs in unwanted parts. To mitigate these effects, this study investigates the potential of a guiding magnetic field in enhancing drug absorption for vascular occlusion treatment. The method relies on guiding magnetic nanoparticles (NPs) loaded with drugs toward the occlusion site using two external magnetic fields. Blood flow was modeled as non-Newtonian, considering shear-rate-dependent viscosity and unsteady at the inlet. To test this idea, a computational fluid dynamic (CFD) coupled with a discrete phase model (DPM) approach has been employed to simulate drug delivery in three-vessel structures with varying degrees of occlusion (45 %, 60 %, and 90 %). To avoid the escape of drug carriers, a secondary magnetic field was applied at the bifurcation point to direct the NPs to the site of blockage where the primary magnetic field acts. Then, the states with or without a guiding source at the bifurcation site are compared based on the capture efficiency of each structure. The simulation demonstrated a significant increase in NP capture at the target site, ranging from 2 % to 15 %, depending on the NP size. However, the severity of occlusion substantially impacted the secondary magnetic field's effectiveness. In the 90 % occlusion scenario, the method's efficiency decreased significantly from 26 % to 16 % for NP sizes exceeding 1.5μm. This study highlights the potential of guiding magnetic fields in improving drug delivery to target sites in vascular occlusion.

Asian Spice Nanotech: Illicium verum made Metal Nanoparticles for Potent Antibacterial and Catalytic Applications

Introduction: Asian spices are globally recognized for their rich phytochemical composition. The bioactive compounds of Asian spices have significant potential to extend the biological applications of metal nanomaterials by increasing their surface area, stability, dispersion, and ecofriendliness. Method: The present study is designed to prepare novel iron oxide (Fe2O3) and copper oxide (CuO) nanoparticles using an aqueous extract of Illicium verum (star anise), a traditional Asian spice as a reducing, capping & stabilizing agent. The synthesized nanoparticles have been characterized to study their molecular environment using Fourier-transform infrared spectroscopy (FTIR). Elemental composition was examined through the Energy dispersive X-ray Spectroscopy (EDS). Scanning Electron Microscopy (SEM) revealed the size, shape, and other morphological characteristics of nanoparticles. The optical properties have been tested through Ultraviolet-Visible (UV) spectroscopy and the band gap energies of both Fe2O3 and CuO nanoparticles have been calculated by using the Tauc plot method, which explores its semiconductor applications. The catalytic applications of obtained nanoparticles have shown significant potential in the degradation of aqueous methyl orange dye (MO). Results: Results revealed that Fe2O3 and CuO nanoparticles significantly increased the rate of reaction by decreasing the reaction time to 45 mins and 40 mins, respectively in comparison to the NaBH4 (60 mins). This shows that CuO has a larger surface area and more absorption capacity than Fe2O3 NPs. To examine the cause of value healthcare, the obtained materials have also been applied against various Gram-positive and Gram-negative bacteria. The bactericidal activity was compared with gentamicin, which showed both nanometals are moderate to strongly active against tested microbes. Conclusion: The successful eco-friendly synthesis of metallic nanoparticles by using Asian spices and their applications in physical and biological sciences opens the door for the scientific community to develop and apply more novel and green nanomaterials in industrial and commercial areas.

Experimental research of convective heat transfer between nanofluids and high-temperature dense granite in deep geothermal reservoirs

Global warming is increasing as CO2 emissions from the use of conventional fossil fuels continue to rise. The development of geothermal energy is gradually becoming the key to the sustainable development of human society in the future. Enhancing the heat transfer performance of circulating heat transfer fluids is one of the effective means to efficiently exploit deep geothermal resources. In this study, a self-developed circulating heat exchange experimental setup was established. The convection heat transfer characteristics of nanofluids in high-temperature rocks were experimentally investigated. Al2O3 nanofluid and CuO nanofluid were used as the working medium for heat transfer in high temperature granite samples. The effects of the Reynolds number (1000–6000) and parameters such as nanoparticle type (CuO & Al2O3), size (20 nm & 40 nm) and mass fraction (0 wt%-2wt%) on the heat transfer intensity were analyzed. The effect of nanoparticle accumulation on the rock surface on the local heat transfer strength was also investigated. The results indicate that the increase of Reynolds number enhances the heat transfer strength of nanofluids in rocks. Nanofluid containing 20 nm Al2O3 nanoparticles has better heat transfer performance in rock than nanofluid containing 20 nm CuO nanoparticles. Meanwhile, the heat transfer performance of nanofluid containing 20 nm Al2O3 nanoparticles in rock is better than that of nanofluid containing 40 nm Al2O3 nanoparticles. The heat transfer intensity increases and then decreases as the nanoparticle mass fraction increases. The heat transfer coefficient at Reynolds number 6000 is 52.2 % higher than that of water. For nanofluids and water, the local heat transfer intensity decreases with increasing distance from the inlet. Meanwhile, accumulation of nanoparticles on rock surfaces during convective heat transfer enhances heat transfer intensity. The results show that nanofluids have the potential to be applied to deep geothermal resource extraction. This paper provides data and technical support for the application of nanomaterials in medium and deep geothermal systems to enhance heat transfer efficiency.

Influencing Factors and Stimulus-Sensitivity of Chitosan/Polymethacrylic Acid (CS/PMAA) Nanogels as Nanocarriers

ABSTRACT Nanogel, nanosized hydrogel, can contribute to biomedical and pharmaceutical, especially in drug delivery, due to its enthralling properties. Small size, large surface area, hydrophilicity, and stimulus responsiveness of nanogel ameliorate tissue penetration, drug loading capacity, and targeted drug delivery. The current study prepared nanosized, pH-sensitive, biocompatible, and stable chitosan/polymethacrylic acid (CS/PMAA) based nanogels using MBA as a crosslinker and APS as an initiator. FTIR confirmed the reaction between functional groups to synthesize nanogels sufficiently in a spherical shape, as affirmed by a FESEM. DLS data revealed nanosized particles with a size range of 70–170 nm and a range of 6–13 for polydispersity index (PDI). A study showed that 2% of MBA crosslinker is sufficient to achieve the desired crosslinking in 60 minutes reaction time (RT) with nanogel size ~ 92 nm. Increasing RT from 30 to 80 minutes during nanogel synthesis demonstrated a decrease in nanogel sizes from 186–73 nm. Synthesized nanogels have shown pH sensitivity (stimuli responsiveness) in acidic and alkaline mediums with an increase in particle size in pH-2 (~144 nm) and pH-8 (~280 nm) compared to intermediate pHs. The pH sensitivity of nanogels by changing the size per the suspended medium’s pH is crucial for prolonged systemic circulation and targeted drug delivery. Moreover, nanogels have shown good colloidal stability with zeta potential (ZP) +28 mv in acidic and −38 mv alkaline mediums. DSC and XRD results demonstrated thermal stability and amorphous morphology of nanogels, respectively. BET surface analysis revealed the surface area of nanogels in the range of 65–68 cm2/g with an average pore size of 28–32 nm. In-vitro cytotoxicity in the L-929 cell line by MTT assay established the cell viability (>70%) after 24 hours of incubation, substantiating the non-toxicity and biocompatibility of nanogels as nanocarriers for drug delivery.

High sulfur content cathode composites utilizing the Li(CB9H10)0.7(CB11H12)0.3 superionic conductor for all−solid−state Li−S batteries

Rechargeable batteries are encountering ever−growing demands for further improvements in energy density and safety. All−solid−state lithium−sulfur (Li−S) batteries have the potential to meet these demands, because they employ not only high−energy−density electrodes but also non−flammable inorganic solid electrolytes. However, the sluggish conducting nature of the S cathode results in high electric transfer barriers, making high S content in solid−state cathode composites difficult. In this study, we report the fabrication and reaction behavior of high S content cathode composites using a Li(CB9H10)0.7(CB11H12)0.3 superionic conductor. The lithium superionic conduction, high deformability, and low material density of Li(CB9H10)0.7(CB11H12)0.3 solid electrolyte facilitate intimate and favorable connections with sulfur and carbon, leading to facile electrical migrations within sulfur−Li(CB9H10)0.7(CB11H12)0.3−carbon (S−CH−C) composites. In battery tests, these close interconnections enable the fabrication of S−CH−C cathode composites through simple physical hand−mixing, allowing for reversible discharge−charge cycling of all−solid−state Li−S batteries engaging high energy density (>1,000 Wh kg−1cathode composite) S−CH−C cathode composites with a high S content of 50 wt%. In addition, a comparative investigation using various carbonaceous conductive materials suggests that simultaneously achieving high surface area, nanoparticle size, and non−spherical rough morphology is crucial for developing high S content S−CH−C composites with superior battery performances.

Detection of Escherichia coli based on CdS QDs nanomarkers and its application in food hygiene and safety

With the continuous exposure of major food safety issues in recent years, food safety has become the focus of people’s attention. As a widely distributed bacterium, excessive levels of Escherichia coli in food may cause gastrointestinal discomfort symptoms, as well as adverse consequences such as food poisoning, acute gastroenteritis, food allergies, and gastric ulcers. Therefore, to ensure food safety and achieve rapid detection of E. coli, this study uses CdS quantum dots (QDs) nanomarkers to detect E. coli in water. Moreover, electrochemical square wave voltammetry is used to determine the relationship between Cadmium (Cd) ion concentration and E. coli concentration in the complex after enzyme-linked immunosorbent reaction. The experiment showed that the average particle size of CdS QDs nanoparticles was 5 nm and they had good biocompatibility. The current magnitude of electrochemical square wave voltammetry was positively correlated with the concentration of Cd ions and E. coli. When the concentration of E. coli was 50-1.0 × 105cfu/mL, its concentration was linearly positively correlated with the magnitude of the current, with a linear correlation coefficient of 0.9873. Compared to the flat plate counting method, its relative error did not exceed 10%, and in addition, the detection time was only 2 h. The above results indicate that CdS QDs nanomarkers can achieve rapid detection of E. coli, effectively improve the detection sensitivity of E. coli, and weaken non-specific adsorption.

Platinum-Catalyzed Silicon Nanowire Growth─Evidence for a Switch from Vapor–Liquid–Solid to Vapor–Solid–Solid Mechanism with Platinum Nanoparticle Size

Platinum-Catalyzed Silicon Nanowire Growth─Evidence for a Switch from Vapor–Liquid–Solid to Vapor–Solid–Solid Mechanism with Platinum Nanoparticle Size

Evaluation of cold plasma treatment technology in biosynthesized silver nanoparticles encapsulated with chitosan by Aliinostoc persicum SA14 against HepG-2

Hepatocellular carcinoma (HCC) is the commonest cancer and the third most common cause of cancer-related mortality. The combination of cold atmospheric plasma (CAP) and nanoparticles is a promising treatment for hepatocellular carcinoma cancers. In the present study, activated water was prepared using the cold atmospheric plasma technique (JET and PAW), and then the biosynthesis ability of silver nanoparticles by the cyanobacterium Aliinostoc persicum SA14 was measured after cultivation in the culture medium containing activated water at 5, 15, and 20 min. After the encapsulation of nanoparticles with chitosan and UV–visible spectroscopy analysis, the characterization of AgNPs, including FTIR analysis. X-ray diffraction, particle size and zeta potential, SEM, TEM, as well as cytotoxicity assays against HepG-2 cell lines, were performed. The comparison of the absorption spectra of silver oxide nanoparticles prepared by the boiling-dender method at concentrations and different times showed that the production of silver nanoparticles was confirmed for all three samples based on the amount of absorption obtained. The outcomes of field emission scanning electron microscopy at all magnifications exhibited that spherical nanoparticles are scattered on the surface of the polymer matrix. Furthermore, the FT-IR spectrum and XRD crystallography confirmed the success of chitosan's production of microcoated silver nanoparticles. The results of the cytotoxicity test against HepG-2 cell lines showed that with increasing concentrations of silver nanoparticles, the survival frequency of cancer cells declined significantly. In conclusion, the tests confirmed that the silver nanoparticles produced by cyanobacteria act as both a stabilizing and reducing agent. The results indicated that CAP decreases nanoparticle size, decreases surface charge distribution of AgNP, and induces uptake, aggregation, and enhanced cytotoxicity against HepG-2 in vitro. The chitosan-AgNPs with cold plasma could have potential applications in the food, agricultural, and pharmaceutical industries.

Three-Dimensional Lymphatics-on-a-Chip Reveals Distinct, Size-Dependent Nanoparticle Transport Mechanisms in Lymphatic Drug Delivery.

Although nanoparticle-based lymphatic drug delivery systems promise better treatment of cancer, infectious disease, and immune disease, their clinical translations are limited by low delivery efficiencies and unclear transport mechanisms. Here, we employed a three-dimensional (3D) lymphatics-on-a-chip featuring an engineered lymphatic vessel (LV) capable of draining interstitial fluids including nanoparticles. We tested lymphatic drainage of different sizes (30, 50, and 70 nm) of PLGA-b-PEG nanoparticles (NPs) using the lymphatics-on-a-chip device. In this study, we discovered that smaller NPs (30 and 50 nm) transported faster than larger NPs (70 nm) through the interstitial space, as expected, but the smaller NPs were captured by lymphatic endothelial cells (LECs) and accumulated within their cytosol, delaying NP transport into the lymphatic lumen, which was not observed in larger NPs. To examine the mechanisms of size-dependent NP transports, we employed four inhibitors, dynasore, nystatin, amiloride, and adrenomedullin, to selectively block dynamin-, caveolin-, macropinocytosis-mediated endocytosis-, and cell junction-mediated paracellular transport. Inhibiting dynamin using dynasore enhanced the transport of smaller NPs (30 and 50 nm) into the lymphatic lumen, minimizing cytosolic accumulation, but showed no effect on larger NP transport. Interestingly, the inhibition of caveolin by nystatin decreased the lymphatic transport of larger NPs without affecting the smaller NP transport, indicating distinct endocytosis mechanisms used by different sizes of NPs. Macropinocytosis inhibition by amiloride did not change the drainage of all sizes of NPs; however, paracellular transport inhibition by adrenomedullin blocked the lymphatic transport of NPs of all sizes. We further revealed that smaller NPs were captured in the Rab7-positive late-stage lymphatic endosomes to delay their lymphatic drainage, which was reversed by dynamin inhibition, suggesting that Rab7 is a potential target to enhance the lymphatic delivery of smaller NPs. Together, our 3D lymphatics-on-a-chip model unveils size-dependent NP transport mechanisms in lymphatic drug delivery.

Rational design of self-assembling ultrashort peptides for the shape- and size-tunable synthesis of metal nanostructures.

Peptides have attracted great interest as platforms for the design of nanocomposite hydrogels due to their distinct bioactivity, biofunctionality and biocompatibility. Previously, we have reported on a family of peptides that self-assembled to form stabilised three-dimensional hydrogel networks, displaying potent antimicrobial activity. In this paper, we report on the use of these hydrogelator sequences and their analogues as stabilisers and growth controllers to synthesise anisotropic gold nanoparticles (AuNPs) of different sizes and shapes. In particular, hollow spherical nanoparticles were obtained for HG2.81-AuNPs, whereas hexagonal nanoparticles were observed for TOH_1N-AuNPs and PentaOH-AuNPs in their respective hydrogel networks. The PentaOH-AuNPs' hydrogel exhibited excellent results with high antimicrobial potency against Staphylococcus aureus and Pseudomonas aeruginosa ATCC 27853 and negligible cytotoxicity. On the other hand, TOH_1N-AuNPs showed no antibacterial activity and no cytotoxicity, demonstrating the versatility of these peptides. This work gives credence towards the development of these materials towards further applications such as in tissue culture technology and wound dressing materials.

Facile green synthesis of plant-mediated selenium nanoparticles (SeNPs) using Moringa oleifera leaf and bark extract for targeting α-amylase and α-glucosidase enzymes in diabetes management

In recent years, nanoparticle synthesis innovations have focused on developing simple, cost-effective, non-toxic, and eco-friendly methods. This study investigates the green synthesis of selenium nanoparticles (SeNPs) using aqueous extracts of Moringa oleifera leaves (ML) and bark (MB) via the precipitation method. The synthesized SeNPs were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). TEM analysis revealed the formation of approximately spherical particles with average sizes ranging from 10.47 nm to 28.5 nm for SeNPs synthesized with ML (SeNPsML) and 15.47 nm–32.83 nm for those with MB (SeNPsMB). XRD analysis indicated that SeNPsMB were predominantly crystalline, while SeNPsML were mainly amorphous with a few crystalline peaks. Morphological studies showed spherically shaped particles with a high degree of agglomeration, evenly distributed throughout the matrix. SeNPsMB exhibited higher dose-dependent inhibition of α-amylase and α-glucosidase compared to SeNPsML, likely due to differences in nanoparticle size and form. These findings suggest that SeNPsMB may possess superior antidiabetic activity.

Understanding the growth kinetics of polydopamine nanoparticles as a function of the temperature and the type of alcohol used as solvent media in their polymerization

Currently, one of the bottlenecks in the large-scale production of particles used for biomedical purposes is reproducibility achieving sizes less than 100 nm. For this reason, the main purpose of this work was to elucidate how the size of polydopamine nanoparticles (PDA NPs), which are widely used in cancer nanomedicine, was affected by several synthesis parameters to facilitate their production scaling-up. Specifically, PDA NPs growth kinetics were investigated as a function of the polymerization temperature (15–50 °C) and the type of alcohol (ethanol, 2-propanol, or a mixture of both) used to produce them, finding that an increase in temperature and the amount of 2-propanol in the solvent media allowed smaller NPs to be obtained. Based on the results achieved, a mathematical model capable of predicting PDA NP diameter as a function of the temperature and reaction time, the NH4OH concentration, and the type of alcohol used to synthesize them was proposed. Also, PDA solubility in the different media was studied to explain NP size behavior depending on the type of alcohol employed, which conditioned the formation of PDA oligomers. Finally, additional assays were conducted to confirm that an increase in the synthesis temperature did not affect some of the most important properties of PDA NPs from a biomedical point of view: their Fe3+-loading capacity and their inherent antitumor activity. Therefore, the results obtained in this research could be useful to scale-up the obtaining of 100 nm PDA NPs in a reproducible manner hereafter without significantly altering their outstanding physical-chemical properties.