Concentration Of Au Nanoparticles Research Articles

Gold nanoparticle microemulsion films with tunable surface plasmon resonance signal

Composite films were prepared by the dip-coating method. An organosol of Au nanoparticles (6.3±0.4 nm) was used as the reaction mixture. The nanoparticles were stabilized with sodium bis(2-ethylhexyl) sulfosuccinate (AOT). The prepared films were formed of an AOT layer with encapsulated Au nanoparticles (i.e. Au@AOT films). The films demonstrated a stable plasmon effect. The variation of the immersion number of the glass substrate from 1 to 10 allowed the adjustment of the plasmonic properties. The absorption intensity and maximum wavelength of the surface plasmon resonance were found to change from 0.183 to 0.245 and from 529±2 to 539±2 nm, respectively. The plasmonic properties were found to correlate with the film thickness, roughness, and morphology. An increase in the concentration of Au nanoparticles improves the film’s mechanical strength and wettability.

NbOx RRAM performance enhancement by surface modification with Au nanoparticles

Resistive random-access memory (RRAM) has been widely studied because of its high information storage density and easy integration, and it has potential to replace traditional memory storage means. However, it is prone to random formations and fracture of conductive filaments, which limits its commercial applications. In this study, magnetron sputtering was used to deposit NbOx films on different substrates modified with different concentrations of Au-nanoparticles (NPs). The as developed Pt-Aumin/NbOx/W tip device with the lowest concentration of Au-NPs modified bottom electrode exhibited the best performance; the Vset distribution of the device was more concentrated, Vreset decreased significantly, the distribution range was narrow, and the resistance distribution of high and low resistance states (HRS and LRS, respectively) was more stable. Modification of the bottom electrode with Au-NPs did not change the ohmic conduction behavior of NbOx RRAM in LRS; however, it changed the resistance switching mechanism from SCLC to P–F effect modified SCLC. The Au-NPs modified bottom electrode acted like a tip, enhancing the local electric field and promoting the formation of conductive filaments near the NPs. This work explains the internal mechanism for improving RRAM properties using a local electric field and provides theoretical guidance for enabling the rapid commercialization of RRAM.

Precision individual dosimetry in Yttrium-90 transarterial radioembolization in the presence of Au nanoparticles

Individual post-treatment dosimetry plays a crucial role in assessing the effectiveness of Y-90 transarterial radioembolization (TARE) treatment. Y-90 positron emission tomography (PET) imaging is widely regarded as the gold standard for post-TARE dosimetry. However, a major limitation of Y-90 PET imaging is the low positron yield of Y-90. This study aimed to address this limitation and improve individual dosimetry using Au nanoparticles (NPs)-induced pair production in Y-90 PET imaging. The GATE Monte Carlo platform was used to simulate post-TARE PET imaging. The study examined five levels of Au NP concentration in the liver tumor: 1%, 5%, 10%, 15%, and 20% by weight. The quality of the acquired PET images was evaluated by calculating the signal-to-background ratio (SBR) and contrast-to-noise ratio (CNR). The errors in PET-based dose volume histograms (DVHPET-based) and reference dose volume histograms (DVHrefrence) were evaluated through various metrics, including root-mean-square error (RMSE), mean absorbed dose (Dmean), and maximum absorbed dose (Dmax). The results showed that as the concentration of Au NPs increased in the tumor, the CNR and SBR values also increased. At concentrations 5 wt% and above, the difference in the values of Dmean and Dmax obtained from the reference dosimetry and PET-based dosimetry is less than 5%. The calculated RMSE values indicated that concentrations 5 wt% and above exhibited acceptable agreement between the DVHPET-based and DVHrefrence. When the concentration of Au NPs increases up to 5 wt%, the presence of Au NPs within the tumor does not significantly affect the Dmean. Conversely, with the presence of Au NPs, at concentrations of 10, 15, and 20 wt%, the Dmean within the tumor experiences reductions of approximately 6%, 10%, and 14%, respectively. The pair production was induced by simultaneously injecting Y-90 and Au NPs into the tumor. Our study demonstrated that dosimetry accuracy in TARE improved through induced positron PET imaging. As a consequence of the dose reduction phenomenon observed upon introducing Au NPs into the tumor, the optimal concentration of Au NPs for enhancing dosimetric precision was determined to be 5 wt%.

Self-assembled Au-CQDs nanofluids with excellent solar absorption and medium–high temperature stability for solar energy harvesting

Nanofluids-based direct absorption solar collectors are promising candidates for medium–high-temperature solar energy harvesting. However, nanofluids’ complicated preparation process and undesirable high-temperature stability have hindered their practical applications. Herein, we propose a facile method for synthesizing gold/carbon quantum dots (Au-CQDs) nanofluids by directly carbonizing the base fluid and spontaneously assembling with Au nanoparticles (AuNPs) triggered by high temperatures. The results indicate that the self-assembled Au-CQDs nanofluids can maintain high stability at 110 °C for 100 h without precipitation and keep excellent photothermal conversion performance under 10 sun irradiation. The concentration and particle size of AuNPs are crucial factors affecting the self-assembly process. By modulating the microscopic morphologies of the self-assembled nanoparticles, the extinction coefficient of the prepared nanofluids is up to 88.7 % at a low loading of 30 ppm. The nanofluids can reach an equilibrium temperature of 50 °C under 1 sun irradiation, 10.4 °C higher than the base fluid due to the enhanced plasmonic effects and stability resulting from the CQDs dotted AuNPs. This work offers a new strategy to fabricate highly stable nanofluids with excellent light absorption properties for efficient solar thermal applications.

Thiol-functionalized mesoporous silica-embedded AuNPs with highly sensitive substrates for surface-enhanced Raman scattering detection

Surface-enhanced Raman spectroscopy (SERS) provides a fast, simple, and label-free approach that can directly detect various analytes attached to SERS substrates and provide qualitative and quantitative information based on the SERS spectra of the analyte. The signal enhancement provided by noble metal particles allows us to achieve high sensitivity and good stability even at low concentrations in water quality testing. Over the past decade, SERS has become increasingly popular in the detection field, highlighting its significant application potential. However, the signal enhancement of single AuNPs is inferior to that of AgNPs, but we can achieve an overall enhancement by uniformly arranging multiple AuNPs. The hot-spot effect, which is crucial for Raman signal enhancement, occurs only when NMNPs are within a specific distance. However, when noble metal particles come into contact with each other, the enhancement effect of the hot spot disappears. Therefore, in this study, AuNPs@MPS-SH substrates with surface-enhanced Raman scattering (SERS) activity were successfully synthesized by immobilizing AuNPs on thiol-functionalized mesoporous silica (MPS-SH). MPS nanospheres with tailored pore size and surface-bound -SH groups were synthesized for the controlled embedding of Au nanoparticles (AuNPs). By adjusting the ratio of reactants, uniform AuNP dispersion and strong MPS-AuNP interactions were achieved. This optimized structure creates localized surface plasmon resonance (LSPR) hotspots, significantly enhancing the surface-enhanced Raman scattering (SERS) effect for ultrasensitive analyte detection. Transmission electron microscopy (TEM) revealed that the average diameter of MPS nanoparticles is 260 nm, with a pore size of 8 nm. Optimal Raman enhancement was achieved at an AuNPs concentration of 2.6 × 1018 particles/mL. The lowest detection limit concentration for Rhodamine 6G was below 10−6 M, while for uremic toxin (urea) it was below 10−3 M. The ability to directly detect low concentrations by mixing with the analyte demonstrates the ultra-high sensitivity and label-free detection potential of this study in the fields of water quality and disease detection.

Zr4+-mercaptosuccinate MOF for the uptake and recovery of gold nanoparticles and gold ions under batch and continuous flow conditions

The increasing use of nanomaterials in commercial products has raised concerns regarding their potential effects on water quality and living organisms. So far, most sorbents available for removing nanosized inorganic pollutants from water rely on electrostatic interactions or entrapment in the sorbent pores. However, this limits their applicability in real wastewater samples containing nanomaterials with variable surface properties and sizes, along with high concentrations of competitive species such as inorganic salts and organics. Little attention has also been paid to the recovery of nanoparticles after sorption. In this work, a Zr4+-mercaptosuccinate metal organic framework (MOF) with free thiol groups was investigated as a sorbent for the removal of Au nanoparticles and Au3+ ions from water. Sorption occurs on the surface of the MOF via the formation of strong metal-thiolate chemical bonds enabling the fast uptake of noble metal nanoparticles and noble metal ions from water (within <1 h). The maximum sorption capacity was found to depend on the size of the Au nanoparticles and ranged from 8 to 41.5 mg/g. The surface functionalization of nanoparticles did not influence sorption performance, which was also maintained in natural waters of variable matrix complexity. The material was also efficient in fixed bed columns with an estimated maximum Au sorption capacity of approximately 7 mg/g, which is significantly higher than the environmental concentrations of Au nanoparticles and adequate for their removal from industrial wastewater. Importantly, the sorbed nanoparticles could be quantitatively recovered (>90 %), at the expense of material degradation, enabling their potential reuse.

Long-Term Intracellular Tracking of Label-Free Nanoparticles in Live Cells and Tissues with Confocal Microscopy.

The label-free imaging of inorganic nanoparticles (NPs) using confocal laser scanning microscopy (CLSM) provides a powerful and versatile tool for studying interactions between NPs and biological systems. Without the need for exogenous labels or markers, it simply benefits from the differential scattering of visible photons between biomaterials and inorganic NPs. Validation experiments conducted on fixed and living cells in real-time, as well as mouse tissue sections following parenteral administration of NPs. Additionally, by incorporating reporter fluorophores and utilizing both reflectance and fluorescence imaging modalities, the method enables high-resolution multiplex imaging of cellular structures and NPs. Different sizes and concentrations of Au NPs are tested as for Ag, Fe3O4, and CeO2 NPs, all with biological interest. Overall, the comprehensive study of NP imaging by confocal microscopy in reflectance mode provides valuable insights and tools for researchers interested in monitoring the nano-bio interactions.

1D ZnO–Au nanocomposites as label-free photoluminescence immunosensors for rapid detection of Listeria monocytogenes

In this study, we explore the potential of 1D ZnO–Au nanocomposites as innovative label-free photoluminescence (PL) immunosensors for rapidly detecting Listeria monocytogenes, a significant concern in food safety. We synthesized ZnO nanorods (ZnO_NR) and nanowires (ZnO_NW), followed by Au deposition to create ZnO_NR/Au and ZnO_NW/Au nanocomposites. Our analyses, including SEM, TEM, Raman spectroscopy, and photoluminescence (PL), revealed distinct structural and optical properties of these nanocomposites, especially noting the superior crystallinity and stability of ZnO_NR/Au. The biosensor performance was evaluated through PL sensitivity to Anti-Listeria antibodies, demonstrating that ZnO_NR with higher concentration of Au nanoparticles exhibited higher sensitivity and a lower limit of detection (LOD), attributed to a greater density of Listeria binding sites. The developed biosensor demonstrated a remarkable limit of detection (LOD) of 8.3 × 102 CFU/mL, rivaling or surpassing conventional culture-based methods and some molecular techniques. This research underscores the critical role of Au deposition duration in optimizing biosensor performance and presents a promising advancement in rapid and sensitive Listeria detection, with significant implications for enhancing food safety protocols.

Raman spectroscopy of active-carbon electrodes when Au colloids are placed at the electrolyte/electrode interface

Surface enhanced Raman spectroscopy (SERS) was used to study active-carbon (A-C) electrodes in super-capacitors cells; these electrodes were functionalized with Au nanoparticles (AuNPs). We observed a large enhancement in the cell's specific capacitance as a function of the AuNPs concentration. Cell capacitance is a volumetric effect while SERS is susceptible to the local number of colloids. The intensity ratio between the D-line (defect line) and the graphitic line (G-line), ID/IG, of the A-C electrode proved to be a good marker, independent of the measurement point. Rather than a peak, typical of amorphous films, this ratio has a dip at a particular AuNPs concentration, which is shifted upon the presence of the electrolyte. It is suggested that the seemingly unrelated phenomena - the capacitance enhancement and the intensity dip - are the result of the formation of a quasi-2D array of AuNPs at the interface between the electrolyte and the electrode.

Evaluating Antimicrobial Effectiveness of Gold Nanoparticles against Streptococcus oralis.

Biofilm includes many microorganisms that causes the periodontal diseases. The increased drugs resistance against the infectious diseases is a major issue owing to excessive using of a broad spectrum of antibiotics. Recently, metallic nanoparticles (NPs) are being administered to control the growth of different types of microorganisms. For instance, gold nanoparticles (Au NPs) are found to be successful to control and limit the bacterial pathogenicity in the oral cavity without any cytotoxic effects on the human body. Aim. In this paper, it was aimed to detect the antibacterial effect of Au NPs and compare with chlorhexidine (CHX) against Streptococcus oralis (S. oralis) in dental plaque of patients with chronic periodontitis. Materials and Methods. First, supragingival and subgingival plaque samples were collected from the patients suffering from periodontal disease and incubated under aerobic or/and anaerobic conditions. Second, the morphological examination, and biochemical test by Vitec 2 machine are used to confirm the S. oralis species. Third, the synthesis of Au NPs was carried out by seed growth method and their properties were characterized. Finally, the antimicrobial effect of the Au NPs against S. oralis was evaluated by Agar well diffusion method for different Au NPs concentrations (100, 50, 25, 12.5, 6.25, 3.125, 1.562, 0.781, 0.391, 0.195, and 0.097 ppm). CHX was used as the positive control and distilled water as the negative control. The antibacterial activity data were statistically analyzed by least significant difference (LSD) using the Statistical Program for Social Science (SPSS) version 22. Results. The Au NPs with an average particles size of 43 nm, polycrystalline face-centered cubic structure were characterized. The Au NPs at 100 ppm concentration had similar antibacterial effect of CHX for inhibiting the growth of S. oralis, with no significant difference. Conclusions. The Au NPs as an antibacterial agent could be equally effective against S. oralis similar to the CHX when used at higher concentration.

Green fabrication of Au nanoparticles as SERS-active substrate for enhancement hydroquinone detection in cosmetics

The detection of hydroquinone (HQ) compounds in cosmetics is a recent challenge due to the limitations of analytical methods and instrumentation. In this research, Au nanoparticles with various concentrations were successfully fabricated, characterized, and used as active substrates at the surface-enhanced Raman spectroscopy (SERS) for HQ detection in cosmetics. The morphological images show the spherical-like structure of Au nanoparticles with an average size diameter of 16.06 nm. The crystalline plane of Au nanoparticles has a diffraction peak at the 2θ: 38.12°, 44.44°, 64.79°, and 77.79° related to miller indices of (111), (200), (220), and (311). The particle size distribution of Au colloid was 32 nm with a potential zeta charge value of − 28.5 mV. The HQ molecules are adsorbed on SERS active substrates with various concentrations of Au nanoparticles. Raman spectroscopy spectrum showed a significant increase in HQ molecules intensity peaks at 441, 797, 898, 1054, and 1162 cm−1, respectively. Colloids of Au nanoparticles implied potential as an active substrate in SERS-based detection and application.

Electrostatically enabled dye reduction using laser synthesized gold nanoparticles

The size and shape-dependent catalytic activities of noble metal nanoparticles (NPs) have been well studied. However, the effect of the surface coating on their catalytic performance is relatively less explored. Herein, we demonstrate that the catalytic activity of NPs has a marked dependence on the type of their surfactant coating. Gold NPs were synthesized by pulsed laser ablation and subsequently coated with different surfactants such as cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVP). This enabled us to keep the size, size distribution, and concentration of Au NP the same for the comparative catalysis study. The bare and coated NPs were employed as a catalyst to carry out the reduction of methylene blue (MB) and methyl orange (MO). The results showed remarkable dependence of the reaction rates on the type of surfactant coating of the catalyst NPs. Bare NPs were found to be far superior to the coated NPs for both reactions. In the case of bare NPs both the dyes were completely reduced in less than 5 mins. Whereas, for coated NPs, the zeta potential values determined their effectiveness for a certain reaction. For instance, the reduction of the cationic dye MB was relatively more effective with NPs with a negative zeta potential value, whereas the reduction of anionic dye MO was better for NPs possessing a positive zeta potential. The apparent rate constant of SDS-coated NPs was 40 times higher than that of the CTAB-coated NPs for the reduction of MB. Conversely, the rate constant is 27-fold higher for CTAB-coated NPs compared to SDS-coated NPs for the reduction of MO. These results imply that there is a strong dependence of the catalytic reaction rates on the relative charge of reactants and NPs. Moreover, the better catalytic performance of bare NPs in both cases highlights the significance of the availability of the unhindered surface for catalysis. These results signify the importance of engineering the right surface coating for NPs for their best catalytic performance.

Tuning lattice strain in Quasi-2D Au-rGO nanohybrid catalysts for dimethylphenylsilane solid state silylation to disiloxane

This study investigates the effect of lattice strain on quasi-2D Au-rGO nanohybrids by growing cubic shape-controlled Au nanocrystals on rGO. To induce the lattice strain, a trisodium citrate capping agent and different concentrations of Au nanoparticles ranging from 0.2 to 1 mM were used. The 0.4 mM Au-rGO was confirmed with a low lattice strain differential of 0.1% between crystallographic planes (111), (200), (220), and (220) (311). The catalytic solid-state activity of 0.4 mM Au-rGO during conversion of dimethylphenylsilane to diphenyltetramethyldisiloxane is highest due to the low lattice strain differential. Following first-order kinetics, more dimethylphenylsilane was converted to diphenyltetramethyldisiloxane at a rate of 5.5 mol. L-1s-1 and 0.75 s-1 rates constant after increasing the solid-state silylation reaction time to 12 h. The findings represent a significant advance towards understanding the synergy of lattice strain in nanomaterials and their activity for the development of quantum catalytic devices.

Reducing the detection limit of trace metals in water by electrodeposition-assisted laser-induced breakdown spectroscopy with gold nanoparticles

This paper used gold nanoparticles to improve the detection limit of laser-induced breakdown spectroscopy (LIBS) for detecting trace metals in water. Firstly, the Pb and Cr elements in water were enriched to the surface of the Al metal substrate by electrodeposition, the substrate surface with Pb and Cr was dripped with Au NPs solution of different concentrations, then dried, and finally, LIBS analysis was carried out. The results showed that the emissions of Pb (I) and Cr (I) rose and then dropped with the Au NPs concentration, reaching the maximum emission intensity when the concentration of Au nanoparticles was 3.91 ng/mL. Secondly, this paper constructed the standard curves of Pb and Cr in the water, and calculated the limit of detection (LOD), finding that the LOD of Pb and Cr at the Au NPs concentrations of 3.91 ng/mL were lower than those without the Au NPs (0 ng/mL). LOD was reduced to less than half of that without gold nanoparticles. The results showed that, compared with electrodeposited LIBS, nanoparticle-enhanced electrodeposited LIBS could realize the high-sensitivity analysis of heavy metals in the water.

Laser-based two-step synthesis of Au-Ag alloy nanoparticles and their application for surface-enhanced Raman spectroscopy (SERS) based detection of rhodamine 6G and urea nitrate

The synthesis of Au-Ag alloy nanoparticles (NPs) by laser beam exposure of a mixture of monometallic nanoparticle colloids is described. The monometallic Ag and Au NPs are first synthesized in water using pulsed laser ablation. Subsequently, the mixture of Ag and Au nanoparticles is irradiated with a nanosecond pulsed laser beam. The kinetics of Au-Ag alloy formation is investigated by adjusting the laser parameters such as laser wavelength, fluence, and exposure time. The alloying process is found to be strictly dependent on the laser wavelength. No alloy formation is detected for 1064 nm laser, while 532 nm laser is found to be effective for alloy formation. Moreover, the extent of alloy formation increases with the rise of fluence and irradiation time of 532 nm laser. The optimum laser fluence and exposure period are 400 mJ/cm2 and 20 min, respectively. In line with the calculations based on the Drude model and quasi-static theory, the wavelength of the SPR peak of alloy NPs showed nonlinear dependence on the concentrations of Ag and Au nanoparticles. In order to study the effectiveness of the AgAu alloy nanoparticles as a SERS substrate, Rhodamine 6G (R6G) and urea nitrate, a well-known ingredient of homemade explosives, are employed as probe molecules. The characteristic peaks of R6G can be detected at concentrations as low as 1 nM. Similarly, 100 µM urea nitrate concentrations are successfully detected.

Assessment of the Potential Health Risk of Gold Nanoparticles Used in Nanomedicine.

Due to unique properties, nanoparticles (NPs) have become a preferred material in biomedicine. The benefits of their use are indisputable, but their safety and potential toxicity are becoming more and more important. Especially, excessive production of reactive oxygen species (ROS) induced by the strong oxidation potential of metal NPs could evoke adverse effects associated with damage to nucleic acids, proteins and lipids. Our study gives a view on the potential cytotoxicity of gold NPs (Au NPs) of different size from the perspective of the redox state of healthy (HEK 293 T) and cancer (A375 and A594) cell lines. These cells were incubated in the presence of two concentrations of Au NPs for 24 h or 72 h and total antioxidant capacity, 8-isoprostane, and protein carbonyl levels were determined. Furthermore, the activity of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, and catalase was detected in cell lysates. Our results compared to the results of other laboratories are very contradictory. The outcomes also differ between healthy and cancer cell lines. However, there are certainly changes in the activities of antioxidant enzymes, as well as the damage to biological molecules due to increased NP-induced oxidative stress. But the final decision of the effect of Au NPs on the oxidative state of selected cell lines requires further research.

Sensing Enhancement of Gold Nanoparticles Doped-TiO&lt;sub&gt;2&lt;/sub&gt; Thin Films as H&lt;sub&gt;2&lt;/sub&gt;S Gas Sensor

Titanium dioxide and gold nanoparticles were synthesized using an environmentally friendly method to deposit undoped and Au-doped TiO2thin films on silicon and glass substrates via the spray pyrolysis technique. The effect of the Au nanoparticles concentrations on structural, morphological, and hydrogen sulfide (H2S) gas sensing characteristics of TiO2thin films were investigated. An X-ray diffraction pattern confirmed the polycrystalline structure of the films deposited on glass and Si substrates with a dominant rutile phase and the formation of additional mixed-phases of Ti-Au bonding. According to a Field Emission-Scanning Electron Microscopy investigation, the cluster size ranged from 20 to 180 nm depending on the concentration of AuNPs. The sensing response of the prepared films was tested against H2S at different operating temperatures. The effect of growing a mixture of titanium-gold phases as a suitable catalyst for hydrogen sulfide sensitivity is also discussed.

Evaluation of Phoma sp. Biomass as an Endophytic Fungus for Synthesis of Extracellular Gold Nanoparticles with Antibacterial and Antifungal Properties.

The aim of our study was to examine the different concentrations of AuNPs as a new antimicrobial substance to control the pathogenic activity. The extracellular synthesis of AuNPs performed by using Phoma sp. as an endophytic fungus. Endophytic fungus was isolated from vascular tissue of peach trees (Prunus persica) from Baft, located in Kerman province, Iran. The UltraViolet-Visible Spectroscopy (UV–Vis spectroscopy) and Fourier transform infrared spectroscopy provided the absorbance peak at 526 nm, while the X-ray diffraction and transmission electron microscopy images released the formation of spherical AuNPs with sizes in the range of 10–100 nm. The findings of inhibition zone test of Au nanoparticles (AuNPs) showed a desirable antifungal and antibacterial activity against phytopathogens including Rhizoctonia solani AG1-IA (AG1-IA has been identified as the dominant anastomosis group) and Xanthomonas oryzae pv. oryzae. The highest inhibition level against sclerotia formation was 93% for AuNPs at a concentration of 80 μg/mL. Application of endophytic fungus biomass for synthesis of AuNPs is relatively inexpensive, single step and environmentally friendly. In vitro study of the antifungal activity of AuNPs at concentrations of 10, 20, 40 and 80 μg/mL was conducted against rice fungal pathogen R. solani to reduce sclerotia formation. The experimental data revealed that the Inhibition rate (RH) for sclerotia formation was (15, 33, 74 and 93%), respectively, for their corresponding AuNPs concentrations (10, 20, 40 and 80 μg/mL). Our findings obviously indicated that the RH strongly depend on AuNPs rates, and enhance upon an increase in AuNPs rates. The application of endophytic fungi biomass for green synthesis is our future goal.

Plasma Jet Prepared Gold and Silver Nanoparticles to Induce Caspase-Independent Apoptosis in Digestive System Cancers

Alot of medical and industrial applications used the metal nanoparticles (NPs) with increase interest to be used as cancer therapy. The current work aimed to prepare AuNPs and AgNPs through the use of plasma jet and test their antitumor mechanism of apoptosis induction. The results indicating the face-centered cubic structures and crystalline nature of AuNPs and AgNPs. Also, the image of FESEM showed that the well dispersions regarding AuNPs and AgNPs, while the NP’s spherical shape with the particle size distributions which are considered to be close that estimated from the XRD. cytotoxicity have been assessed against the Normal embryonic cell line REF and the digestive system (HC , SK-GT-4) cell lines under a variety of the series dilute of the Ag and Au NPs (6.25, 12.5, 25, 50 and 100%), have been determined through a microtetrazolium (MTT) assay. The capacity of Ag and Au NPs to induce apoptosis to an infected cell has been studied by crystal violet stain to measure the percentage of induction of apoptosis. In cases where 100 μg\ml Au NP concentrations are 69.60 percent, the maximum cytotoxicity of the HC cell line was reported, while 100 μg\ml Au NP was 69.20% for the SKg cell line exposure. qRT-PCR in AuNPs and AgNPs treated of (HC and SKG) cell lines revealed a remarkable in the expression of BAX, BCL2 and AIF, Endo G (independent pathway).

Entropy analysis of thermally radiating MHD slip flow of hybrid nanoparticles (Au-Al2O3/Blood) through a tapered multi-stenosed artery

This paper deals with the heat transfer and entropy generation analysis of unsteady blood flow through a tapered multi-stenosed artery incorporating hybrid nanoparticles (gold and alumina) with Joule heating, viscous dissipation, radiation, and inclined magnetic field. For the realistic behavior of blood, Reynold’s viscosity model is considered in this study. The Crank-Nicolson scheme is applied to solve the continuity, momentum, and energy equations with appropriate initial and boundary conditions. The important findings are represented graphically and have been analyzed for different values of the dimensionless parameters. The velocity contours for several emerging parameters are presented to study the overall behavior of blood flow patterns. It is observed that the axial flow accelerates with increasing wall slip velocity (ws) due to the presence of the hydrodynamic wall slip effect. The velocity profile increases as the concentration of Au nanoparticles increases, while the reverse effect is noted for the concentration of Al2O3 nanoparticles. The current findings may be helpful for biomedical scientists who are interested in investigating the treatment of various cardiovascular diseases.