Shape Of Nanoparticles Research Articles

Development of a bottom-up coarse-grained model for interactions of lipids with TiO nanoparticles.

Understanding interactions of inorganic nanoparticles with biomolecules is important in many biotechnology, nanomedicine, and toxicological research, however, the size of typical nanoparticles makes their direct modeling by atomistic simulations unfeasible. Here, we present a bottom-up coarse-graining approach for modeling titanium dioxide (TiO ) nanomaterials in contact with phospholipids that uses the inverse Monte Carlo method to optimize the effective interactions from the structural data obtained in small-scale all-atom simulations of TiO surfaces with lipids in aqueous solution. The resulting coarse-grained models are able to accurately reproduce the structural details of lipid adsorption on different titania surfaces without the use of an explicit solvent, enabling significant computational resource savings and favorable scaling. Our coarse-grained simulations show that small spherical TiO nanoparticles ( nm) can only be partially wrapped by a lipid bilayer with phosphoethanolamine headgroups, however, the lipid adsorption increases with the radius of the nanoparticle. The current approach can be used to study the effect of the size and shape of TiO nanoparticles on their interactions with cell membrane lipids, which can be a determining factor in membrane wrapping as well as the recently discovered phenomenon of nanoquarantining, which involves the formation of layered nanomaterial-lipid structures.

Enhancement of Visible Light Antibacterial Activities of Cellulose Fibers from Lotus Petiole Decorated ZnO Nanoparticles.

Cellulose/ZnO (CZ) nanocomposites are promising antimicrobial materials known for their antibiotic-free nature, biocompatibility, and environmental friendliness. In this study, cellulose fibers extracted from lotus petioles were utilized as a substrate and decorated with various shapes of ZnO nanoparticles (NPs), including small bean, hexagonal ingot-like, long cylindrical, and hexagonal cylinder-shaped NPs. Increasing zinc salt molar concentration resulted in highly crystalline ZnO NPs forming and enhanced interactions between ZnO NPs and -OH groups of cellulose. The thermal stability and UV-visible absorption properties of the CZ samples were influenced by ZnO concentration. Notably, at a ZnO molar ratio of 0.1, the CZ 0.1 sample demonstrated the lowest weight loss, while the optical band gap gradually decreased from 3.0 to 2.45eV from the CZ 0.01 to CZ 1.0 samples. The CZ nanocomposites exhibited remarkable antibacterial activity against both Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria under visible light conditions, with a minimum inhibitory concentration (MIC) of 0.005mg/mL for both bacterial strains. The bactericidal effects increased with higher concentrations of ZnO NPs, even achieving 100% inhibition. Incorporating ZnO NPs onto cellulose fibers derived from lotus plants presents a promising avenue for developing environmentally friendly materials with broad applications in antibacterial and environmental fields.

Effect of aspect ratio on the x-ray attenuation of nanoparticles: A theoretical study

PurposeThere has been a significant focus on the potential applications of nanoparticle suspensions in the past few decades particularly as targeted contrast agents for specific pathological conditions. However, the question of optimal size and shape of nanoparticles for contrast enhancement is inadequately addressed. MethodsWe present a comprehensive and conclusive theoretical analysis using first principles by considering the attenuating property of a single nanoparticle of any arbitrary shape. As a special case, ellipsoidal nanoparticles and nanorods are considered, for two independent directions of incidence of x-rays. These results are extended for a suspension of nanoparticles in a liquid. ResultsIt is seen that for a nanoparticle with dimensions much less than 1/μ(E), where μ(E) is the attenuation coefficient of the material, the attenuation by the nanoparticle is independent of its shape and size; and attenuation per unit mass reduces as the nanoparticle size increases. ConclusionsTo achieve maximum attenuation, the nanoparticle sizes should be as small as possible, immaterial of the shape, as long as the dimensions are smaller than 150 nm.

Conductive nano-Al/polyaniline composites prepared via mechanical milling

The conductive nano-Al/polyaniline composites were prepared by the milling method in the solid state. Here, aluminum nanostructures were prepared in two different mechanical methods, wire drawing and wire milling in the presence of lubricant oil. The effects of the preparation methods on the structures and morphologies of aluminum nanostructures were investigated by XRD and FESEM. The results show that the shape and size of aluminum nanoparticles in the preparation by the wire drawing method are significantly different than the wire milling method. The aluminum nanostructures were prepared by milling method have flake-like nanosheets while the wire drawing method leads to the formation of spherical ultrafine nanoparticles, which particles size are in the range of 30–60 nm. Then, polyaniline was produced using a solid-state polymerization process by the chemical reaction between aniline hydrochloride and potassium peroxydisulfate. Finally, nano-Al/polyaniline composites were prepared by mechanical milling at room temperature. The quantitative analysis was carried out with the materials analysis using diffraction (MAUD) method and weight fraction for aluminum and PANI were calculated 6.66% and 93.34%, respectively. Electrical conductivity measurements show the conductivity (1.2 × 10−2 S cm−1 at 25 °C) for polyaniline emeraldine salt and (1.02 × 10−3 S cm−1 at 25 °C) in nanocomposite respectively. The results show that by adding aluminum nanoparticles to the polymer the conductivity of nanocomposite (Al/PANI-ES) is lower than that for pure (PANI-ES). Thermogravimetry and differential thermal analysis curves show pure (PANI-ES) and nanocomposite (Al/PANI-ES) have a similar thermal degradation process. The total weight loss in TG curve of pure PANI-ES, in the temperature range 45–800 °C is 46.28% but, total weight loss observed in nanocomposite is 38.67%. Therefore, nanocomposite has higher thermal stability than that of the pure PANI-ES.

Polymeric Nanoparticles as Oral and Intranasal Peptide Vaccine Delivery Systems: The Role of Shape and Conjugation.

Mucosal vaccines are highly attractive due to high patient compliance and their suitability for mass immunizations. However, all currently licensed mucosal vaccines are composed of attenuated/inactive whole microbes, which are associated with a variety of safety concerns. In contrast, modern subunit vaccines use minimal pathogenic components (antigens) that are safe but typically poorly immunogenic when delivered via mucosal administration. In this study, we demonstrated the utility of various functional polymer-based nanostructures as vaccine carriers. A Group A Streptococcus (GAS)-derived peptide antigen (PJ8) was selected in light of the recent global spread of invasive GAS infection. The vaccine candidates were prepared by either conjugation or physical mixing of PJ8 with rod-, sphere-, worm-, and tadpole-shaped polymeric nanoparticles. The roles of nanoparticle shape and antigen conjugation in vaccine immunogenicity were demonstrated through the comparison of three distinct immunization pathways (subcutaneous, intranasal, and oral). No additional adjuvant or carrier was required to induce bactericidal immune responses even upon oral vaccine administration.

Synthesis of AuNPs in microemulsion and nano-emulsion systems using aqueous extract of C. chayamansa leaves as reducing agent

This paper explores the synthesis and characterization of gold nanoparticles using various microemulsion and nano-emulsion systems. The pseudo-ternary system consists of an aqueous phase / Brij O10: 1,2-hexanediol (1:1) / castor oil; the aqueous phases include the aqueous extract of Chaya Maya (Cnidoscolus chayamansa) leaves or aqueous extract of Chaya maya leaves combined with the inorganic gold precursor. Chaya maya extract act as a reducing agent for gold (III) ions. The influence of aqueous phase content and surfactant concentration on gold nanoparticles size, morphology, and stability is investigated. Dynamic Light Scattering, Scanning Transmission Electron Microscopy, and UV-Vis spectroscopy are employed to analyze the synthesized gold nanoparticles. The sizes of the gold nanoparticles obtained were influenced by the system composition and are within the range of 19–40 nm. Results indicate that increasing the aqueous phase content generally leads to larger nanoparticle sizes, while higher surfactant concentrations yield smaller nanoparticles. A transition from microemulsion to nano-emulsion is observed at a specific aqueous phase content, marking a shift in nanoparticle size distribution and growth behavior. Additionally, microemulsion and nano-emulsion systems provide stability to gold nanoparticles, as evidenced by measured Zeta potentials indicating negatively charged surfaces conducting to colloidal stability. Also, remark that the use of organometallic precursors is no needed to obtain very good results on nanoparticle size and shape when O/W systems are used to this end. These findings highlight the potential of tailored microemulsion and nano-emulsion systems formulated with low-toxic components for controlling gold nanoparticles properties under mild conditions, contributing to the development of advanced gold nanoparticles-based materials with enhanced functionalities, with implications for diverse applications.

Butea monosperma aided green synthesis of α-MoO3 nanoparticles: Biosensing and photocatalytic activity towards hazardous dyes and rangoli colorants

Increasing environmental pollutants and the need for efficient photocatalytic and biosensing materials have led to the development of novel green synthesis methods. In this study, MoO3 nanoparticles (NPs) were successfully synthesized by using green chemistry approach. In that respect, Butea monosperma leaf powder was used as a novel fuel. Structural parameters, optical properties, shape and morphology of MoO3 NPs are examined using XRD, FTIR, UV–Vis spectrophotometer, Photoluminescence (PL), SEM - EDAX and TEM analysis. The use of MoO3 NPs as a dusting agent in fingerprint applications results in improved fingerprint visibility, which is useful in forensic investigation. In this study, we modified the GCE electrode surface with MoO3 NPs to develop a highly sensitive dopamine (DA) sensor. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were used to investigate the electrochemical behaviour and electrocatalytic property of the MoO3 NPs. The synthesized NPs have excellent performance for detection of highly sensitive biologically active DA. The sensor exhibits a low detection limit of 0.45 μM. Additionally, it shows good stability, simplicity, and selectivity for the rapid detection of DA. MoO3 NPs shows good photocatalytic activity under UV light for the degradation of important textile industries dye such as methylene blue (MB) and harmful rangoli colors which are available in local shops of Tumkur, Karnataka. The photocatalyst exhibits a remarkable 97 % degradation efficiency for MB dye. Coumarin studies ensure the effective generation of OH radicals on the surface of the photocatalyst, leading to the degradation of organic dyes. Additionally, the MoO3 NPs reusability was examined, and even after four cycles, the level of photocatalytic activity did not drop much. Therefore, it is a potential photocatalyst for the processing of organic colours.

Pulsatile flow of Casson hybrid nanofluid between ternary-hybrid nanofluid and nanofluid in an inclined channel with temperature-dependent viscosity

This study presents a mathematical model for layered non-miscible liquid flow in an inclined channel subject to a pulsatile pressure gradient. The Casson hybrid nanofluid (hnf) is sandwiched between the layers of Newtonian ternary hybrid nanofluid (t-hnf) and nanofluid (nf). Additionally, the impact of temperature-dependent viscosity is taken into consideration. Multiwall carbon nanotubes, molybdenum disulfide, and silver are considered nanoparticles, with water and kerosene oil as base fluids. The governing partial differential equations are transformed into coupled non-linear ordinary differential equations (ODEs) using the perturbation technique. The resulting ODEs are solved numerically using MATHEMATICA software with the help of the shooting technique associated with the Runge-Kutta fourth-order scheme. The behaviors of numerous sundry parameters against velocity, temperature, concentration, and shear stress are depicted graphically and in tabular form. The outcomes of the study reveal that if the viscosity is held constant, then the fluid’s velocity is initially low and gradually increases as the viscosity variation parameter rises. The velocity of fluid flow is higher when a Newtonian fluid occupies the middle region of the channel than when Casson fluid does. The increase in the nanoparticle shape factor, at both boundaries, results in an increase in the rate of heat transfer.

Gamma Ray-Induced Changes in Polyvinyl Alcohol/Carboxymethyl Cellulose/Cadmium Selenide Nanocomposite Films: Optical Analysis for Optoelectronic Devices

In order to create nanocomposite films (NC) of polyvinyl alcohol, carboxymethyl cellulose and cadmium selenide nanoparticles (PVA/CMC/CdSe), thermolysis and ex-situ casting techniques were used. The microstructure and shape of the CdSe nanoparticles (NP) were characterized with the Rietveld method and transmission electron microscopy (TEM). Rietveld refinement of the x-ray data showed that the prepared CdSe NP had the cubic zinc blend structure with a lattice parameter 6.057 Å. The TEM showed the formation of the dotted shape of CdSe with a particle size around 2 nm, confirming the quantum dot size of the mother phase CdSe. Samples from the prepared PVA/CMC/CdSe films were irradiated with γ radiation doses of 20−150 kGy. The resultant effects of the γ ray irradiation on the optical and color properties of the prepared films were investigated using UV–vis spectroscopy and the International Commission on Illumination (CIE) color difference technique. When the γ dose was increased to 150 kGy, the maximum dose used, the direct and indirect optical band gaps (Eg) decreased. We attribute this decrease to the domination of crosslinking that destroyed the ordered structure and thus increased the amorphous regions. In addition, we used the optical dielectric loss (ε”) to identify the type of microelectronic transition for the PVA/CMC/CdSe NC samples, which was found to be a direct allowed transition. The effect of γ ray irradiation on the absorbance, extinction coefficient, refractive index, dielectric parameters and optical conductivity of the NC samples were studied. The enhancement in the optical properties indicated that the γ radiation is a useful tool that allows the use of the resulting PVA/CMC/CdSe NC in optoelectronic devices. Finally, the color differences between the pristine and irradiated films were estimated. The irradiated PVA/CMC/CdSe NC film exhibited significant color differences relative to the pristine films.

A High-Performance Cr2O3/CaCO3 Nanocomposite Catalyst for Rapid Hydrogen Generation from NaBH4.

This study aims to prepare new nanocomposites consisting of Cr2O3/CaCO3 as a catalyst for improved hydrogen production from NaBH4 methanolysis. The new nanocomposite possesses nanoparticles with the compositional formula Cr2-xCaxO3 (x = 0, 0.3, and 0.6). These samples were prepared using the sol-gel method, which comprises gelatin fuel. The structure of the new composites was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, environmental scanning electron microscopy (ESEM), and X-ray spectroscopy (XPS). The XRD data showed the rhombohedral crystallinity of the studied samples, and the average crystal size was 25 nm. The FTIR measurements represented the absorption bands of Cr2O3 and CaO. The ESEM micrographs of the Cr2O3 showed the spherical shape of the Cr2O3 nanoparticles. The XPS measurements proved the desired oxidation states of the Cr2-xCaxO3 nanoparticles. The optical band gap of Cr2O3 is 3.0 eV, and calcium doping causes a reduction to 2.5 and 1.3 eV at 15.0 and 30.0% doping ratios. The methanolysis of NaBH4 involved accelerated H2 production when using Cr2-xCaxO3 as a catalyst. Furthermore, the Cr1.7Ca0.3O3 catalyst had the highest hydrogen generation rate, with a value of 12,750 mL/g/min.

Size Dependence of Gold Nanorods for Efficient and Rapid Photothermal Therapy.

In recent years, gold nanomaterials have become a hot topic in photothermal tumor therapy due to their unique surface plasmon resonance characteristics. The effectiveness of photothermal therapy is highly dependent on the shape and size of gold nanoparticles. In this work, we investigate the photothermal therapeutic effects of four different sizes of gold nanorods (GNRs). The results show that the uptake of short GNRs with aspect ratios 3.3-3.5 by cells is higher than that of GNRs with aspect ratios 4-5.5. Using a laser with single pulse energy as low as 28 pJ laser for 20 s can induce the death of liver cancer cells co-cultured with short GNRs. Long GNRs required twice the energy to achieve the same therapeutic effect. The dual-temperature model is used to simulate the photothermal response of intracellular clusters irradiated by a laser. It is found that small GNRs are easier to compact because of their morphological characteristics, and the electromagnetic coupling between GNRs is better, which increases the internal field enhancement, resulting in higher local temperature. Compared with a single GNR, GNR clusters are less dependent on polarization and wavelength, which is more conducive to the flexible selection of excitation laser sources.

Controllable shaping of high-index dielectric nanoparticles by exploiting the giant optical force of femtosecond laser pulses

Nanoparticles made of different materials usually support optical resonances in the visible to near infrared spectral range, such as the localized surface plasmons observed in metallic nanoparticles and the Mie resonances observed in dielectric ones. Such optical resonances, which are important for practical applications, depend strongly on the morphologies of nanoparticles. Laser irradiation is a simple but effective way to modify such optical resonances through the change in the morphology of a nanoparticle. Although laser-induced shaping of metallic nanoparticles has been successfully demonstrated, it remains a big challenge for dielectric nanoparticles due to their larger Young’s modulus and smaller thermal conductivities. Here, we proposed and demonstrated a strategy for realizing controllable shaping of high-index dielectric nanoparticles by exploiting the giant optical force induced by femtosecond laser pulses. It was found that both Si and Ge nanoparticles can be lit up by resonantly exciting the optical resonances with femtosecond laser pulses, leading to the luminescence burst when the laser power exceeds a threshold. In addition, the morphologies of Si and Ge nanoparticles can be modified by utilizing the giant absorption force exerted on them and the reduced Young’s modulus at high temperatures. The shape transformation from sphere to ellipsoid can be realized by laser irradiation, leading to the blueshifts of the optical resonances. It was found that Si and Ge nanoparticles were generally elongated along the direction parallel to the polarization of the laser light. Controllable shaping of Si and Ge can be achieved by deliberately adjusting the excitation wavelength and the laser power. Our findings are helpful for understanding the giant absorption force of femtosecond laser light and are useful for designing nanoscale photonic devices based on shaped high-index nanoparticles.

Self-hybridisation between interband transitions and Mie modes in dielectric nanoparticles

Abstract We discuss the possibility of self-hybridisation in high-index dielectric nanoparticles, where Mie modes of electric or magnetic type can couple to the interband transitions of the material, leading to spectral anticrossings. Starting with an idealised system described by moderately high constant permittivity with a narrow Lorentzian, in which self-hybridisation is visible for both plane-wave and electron-beam excitation, we embark on a quest for realistic systems where this effect should be visible. We explore a variety of spherical particles made of traditional semiconductors such as Si, GaAs, and GaP. With the effect hardly discernible, we identify two major causes hindering observation of self-hybridisation: the very broad spectral fingerprints of interband transitions in most candidate materials, and the significant overlap between electric and magnetic Mie modes in nanospheres. We thus depart from the spherical shape, and show that interband–Mie hybridisation is indeed feasible in the example of GaAs cylinders, even with a simple plane-wave source. This so-far unreported kind of polariton has to be considered when interpreting experimental spectra of Mie-resonant nanoparticles and assigning modal characters to specific features. On the other hand, it has the potential to be useful for the characterisation of the optical properties of dielectric materials, through control of the hybridisation strength via nanoparticle size and shape, and for applications that exploit Mie resonances in metamaterials, highly-directional antennas, or photovoltaics.

Silver(I)-induced anisotropy in the plasmon-driven growth of nanoscale gold

ABSTRACT The plasmon-mediated synthesis of anisotropic gold nanoparticles (AuNPs) has only recently been investigated and achieved. This process typically utilizes the surface plasmon resonances (SPRs) of the nanoparticles themselves to drive metal deposition and growth. Many of the traditional methods for shape control, including use of functional surfactants and etchants, have yet to be utilized within the context of light-driven synthesis. Here, the underpotential deposition of Ag(I) is utilized as a shape-controlling strategy in a hot electron-driven photochemical synthesis to grow anisotropic gold nanoparticles. The strategy also relies on L-pyroglutamic acid, a natural amino acid metabolite, as a photochemical relay aiding in the transport and localization of plasmon-generated hot electrons. By carefully adjusting reagent concentrations, the morphologies of the resulting nanoparticles can be facilely tuned from spheres to nanostars and nanoflowers. The high extinction in the NIR region of the ‘ideal’ gold nanostars synthesized advocates their use as photothermal therapy agents, supported by a sufficient photothermal conversion efficiency (η = 30.8%) under 808 nm CW laser irradiation. This contribution expands the repertoire of gold nanostructures accessible to visible-light-driven plasmonic photochemistry. Different gold nanoparticle shapes have been accessed using a plasmon-mediated growth technique. Ag(I) ions induce symmetry breaking, yielding nano-sized gold spheres, stars, and flowers. A specialized photoreactor, equipped with 505 nm LED illumination, facilitates the transfer of hot electrons from a pre-made gold nanocube seed surface. Gold reduction and deposition occur, and anisotropic structures grow with the aid of L-pyroglutamic acid and Triton X-100 as coordinating and shape-directing agents.

Green synthesis of ZnO nanoparticles by Myrtus communis plant extract with investigation of effect of precursor, calcination temperature and study of photocatalytic performance

An elegant approach was made for the synthesis of ZnO nanoparticles by Myrtus Communis plant extract using two different precursors at variable temperatures (400,600, and 800 °C). The properties of nanoparticles were investigated with PXRD, SEM-EDX, PL, FTIR, and UV–Vis spectrometer. PXRD results inferred that all samples have pure wurtzite phase confirming with JCPDS card No. 36–1451. The UV–Vis spectroscopy exhibited that all estimated bandgaps are a little less than those for bulk ZnO. It was confirmed by EDX spectra that Zn and O atoms are the main compositions of the material. FESEM images displayed hexagonal-like shapes of nanoparticles for all samples prepared with acetate. Hexagonal morphology was observed in the samples having green emission at room temperature PL measurements. It was seen that methylene blue degraded about 90 % after about 20 min of irradiation of UV light for samples calcined at 400 °C. It was also observed that the samples calcined at 400 °C degraded methylene blue by approximately 99 %. This work is the first paper on the morphological utilization and photocatalytic performance of green synthesized ZnO with Myrtus communis plant extract with various calcination temperatures via two different precursor reagents.

Green synthesis of zinc oxide nanoparticles using aqueous extract of shilajit and their anticancer activity against HeLa cells

In the present study, ZnO nanoparticles have been synthesized using an aqueous extract of shilajit. The nanoparticles were characterized using different techniques such as UV (ultraviolet–visible spectrophotometer), FTIR (Fourier transform infrared), XRD (X-ray diffraction), particle size analysis, SEM (scanning electron microscope) and EDAX (Energy-dispersive X-ray) analysis. The UV absorption peak at 422.40 nm was observed for ZnO nanoparticles. SEM analysis showed the shape of nanoparticles to be spherical, FTIR spectrum confirmed the presence of zinc atoms, particle size analysis showed the nanoparticle size, EDAX confirmed the purity of ZnO nanoparticles whereas XRD pattern similar to that of JCPDS card for ZnO confirmed the presence of pure ZnO nanoparticles. The in vitro anticancer activity of ZnO nanoparticles against the HeLa cell line showed the IC50 value of 38.60 μg/mL compared to reference standard cisplatin. This finding confirms that ZnO nanoparticles from shilajit extract have potent cytotoxic effect on human cervical cancer cell lines.

Significance of nanoparticles shape for enhanced heat transfer over on elastic sheet

This study analyzes the impact that the shape of nanoparticles has on the rate at which heat is transferred over an elastic sheet, which is one of the most important aspects of thermal management. It addresses the pressing demand for effective heat dissipation and insulation in a variety of industries, including energy systems and electronic devices, among others. The importance of this work rests in the fact that it has the potential to make conventional methods of heat transmission obsolete. By gaining an understanding of how the morphologies of nanoparticles affect their thermal properties, we may pave the way for the development of novel materials and applications, which will ultimately result in increased energy efficiency and high-performance technology. The originality by arguing that the study fills a knowledge gap on how different nanoparticle shapes influence heat transport in elastic sheets. The importance of this property for applications such as electronics and materials research should be emphasized. Within the scope of this study, a nanofluid composed of copper and water is utilized to investigate the movement of heat between the stretching sheets. This objective is supported by the utilization of the Hamilton Crosser Model as a tool. Platelets, cylinders, and blocks are some of the shapes and sizes of the nanoparticles that are utilized in this process. A magnetic field is applied, which changes the thermal properties of the nanofluids that are being used in the process of exchanging heat between two objects. This makes the process go more quickly. A similarity transformation is used to convert the governing equations into a collection of ordinary differential equations (ODEs). By using the shooting method, the boundary value problem can be converted into an initial value problem. This is achievable since the shooting technique is a shooting method. After that, a numerical solution is found for this issue using the RK-4 method. We give visual data that demonstrates how the flow pattern and temperature profile change as a result of a variety of different causes. Plots are provided for both the Nusselt number and the skin friction coefficient. As the inquiry goes on and the values of the key parameters are changed, one thing that happens consistently across all forms of nanoparticles is an increase in the velocity profile. This is a pattern. In addition, the nanofluid that is formed of platelet-shaped nanoparticles (which has a bigger value of shape factor) is shown to have the greatest temperature. This finding demonstrates a clear association between temperature and shape factor.

Optimized Refolding Buffers Oriented Humoral Immune Responses Versus PfGCS1 Self-Assembled Peptide Nanoparticle.

Developing a novel class of vaccine is pivotal for eliminating and eradicating malaria. Preceding investigations demonstrated partial blocking activity in malaria transmission against recombinant vaccine PfHAP2-GCS1 and conserved region of the cd loop. The effectiveness of immune response varies with the size and shape of the self-assembly of peptide nanoparticles (SAPNs) displaying antigen, affected by different components in refolding buffers. Plasmodium falciparum Generative Cell Specific 1 (PfGCS1), a promising malaria transmission-blocking vaccine (TBV) candidate, was expressed, purified, and followed by a four-step refolding process to form nanoparticles (PfGCS1-SAPNs). The influence of buffer components on the size and shape of SAPNs was investigated by DLS and FESEM. Furthermore, the immunogenicity of nanostructures was assessed in different mouse groups. The results showed that PfGCS1-SAPN was immunogenic and its administration with Poly (I:C), stimulated humoral and cellular responses in the mouse model. In the immunized mice groups, the level of IgG antibodies against PfGCS1-SAPN was significantly increased in different time points (second and third boost) and heterogeneous boosters. The various IgG-subclasses profile shifted to Th1, Th2, or Th1/Th2 mix responses in mice immunized with PfGCS1-SAPN refolded in different buffers, indicating a prerequisite for further investigations to optimize vaccine formulation to enhance and modulate Th1/cellular responses. Such studies pave the way to improve biophysical features related to the nanoparticles' size, shape, and conformational epitopes of candidate antigens and T- and B-cells presented on the superficial structure to elicit robust immune responses.

Similarity analysis of bioconvection of unsteady nonhomogeneous hybrid nanofluids influenced by motile microorganisms.

Motile bacteria in hybrid nanofluids cause bioconvection. Bacillus cereus, Pseudomonas viscosa, Bacillus brevis, Salmonella typhimurium, and Pseudomonas fluorescens were used to evaluate their effect and dispersion in the hybrid nanofluid. Using similarity analysis, a two-phase model for mixed bioconvection magnetohydrodynamic flow was developed using hybrid nanoparticles of Al2O3 and Cu (Cu-Al2O3/water). The parametric investigation, covering the magnetic parameter, permeability coefficient, nanoparticle shape factor, temperature ratio, radiation parameter, nanoparticle fraction ratio, Brownian parameter, thermophoresis parameter, motile bacteria diffusivity, chemotaxis parameter, and Nusselt, Reynold, Prandtl, Sherwoodnumbers, as well as the number of motile microorganisms', showed significant outcomes. Velocity and shear stresses are sensitive to M, Pr, and [Formula: see text]. Magnetic, radiation, and chemotaxis factors impact bacterial density. The hybrid nanofluid velocity decreases when the magnetic parameter, M, Prandtl number Pr increases, while it increases with the increasing of porosity coefficient, [Formula: see text], and the hybrid nanoparticle ratio Nf. The temperature distribution decreases with the increasing of Prandtl number and Nf. Increasing temperature differential and bacterium diffusivity increases bacterial aggregation.

Investigation of selective SERS enhancement mechanism of Au nanospheres and Au nanorods based on 2T2D-SERS correlation spectroscopy

The selective enhancement mechanism in surface-enhanced Raman scattering (SERS) is demonstrated. Two different types of single nanoparticles (Au nanosphere and Au nanorod) were used to investigate the role of the localized surface plasmon resonance (LSPR) in SERS spectra by using the two-trace two-dimensional (2T2D) correlation spectroscopy. The SERS intensities of three probe molecules, 4-mercaptobenzoic acid (4-MBA), 4-aminothiophenol (4-ATP), and 4-bromobenzenethiol (4-BBT), respectively, were enhanced but slightly different when adsorbed on Au nanospheres and Au nanorods. 2T2D correlation SERS spectra clearly showed that even with the same shape of Au nanoparticles, the main factors influencing the SERS enhancement can vary depending on the specific type of SERS tags used. Such subtle difference could not be clearly identified by the conventional spectral analysis. This result sheds light on potential applications of 2T2D correlation spectroscopy. For 4-MBA molecules, the a1 and b2 modes are mainly affected by the Au nanospheres and Au nanorods. For 4-ATP molecules, the a1 and b2 modes related to C–S stretching combined with C–C stretching band are mainly affected by Au nanorods and Au nanospheres. For 4-BBT molecules, the a1 and b2 modes of C–C (aromatic ring) stretching band are mainly affected by Au nanorods and Au nanospheres. This study offers valuable insights into the relationship between nanoparticle shape and SERS enhancement.