Gold nanoparticles induced apoptosis via oxidative stress and mitochondrial dysfunctions in MCF‐7 breast cancer cells

Green synthesis of functionalized gold nanoparticles has been considered to be more biocompatible and has gained much attention in recent years. The eco‐friendly synthesis, long half‐life of drugs, low cost, and nontoxicity make them an appealing potential option for the biomedical field. The leaf aqueous extract of 10 different plants, namely, Araucaria heterophylla (Ah), Lagerstroemia indica (Li), Combretum indicum (Ci), Melia azedarach (Ma), Muntingia calabura (Mc), Hygrophila auriculata (Ha), Rivina humilis (Rh), Callistemon lanceolatus (Cl), Pterygota alata (Pa), and Vateria indica (Vi) was used for the synthesis of gold nanoparticles (AuNPs). Among them, six plants supported the synthesis of stable AuNPs. The generation of ruby red from pale yellow color proved AuNPs synthesis and which was further confirmed by the absorption peak in UV–Vis spectroscopy. Enhanced antioxidant activity was found with Pa–AuNPs compared with other phytosynthesized AuNPs. Pa–AuNPs were thus characterized by HR‐TEM, EDX, XRD, and FTIR. Pa–AuNPs exhibited potent dose‐dependent anticancer efficacy and an effective dose of IC₅₀ mediated apoptosis and necrosis in MCF‐7 breast cancer cells. Pa–AuNPs significantly enhanced the generation of ROS, in effect inducing mitochondrial membrane sensitization to trigger the cascade of apoptosis. The research highlights the effectiveness of AuNPs on cancer cells in vitro and, in turn, a progressive step toward novel biomedical applications. These findings indicate that phytosynthesized AuNPs may be an enticing anti‐cancer strategy for breast cancer without eliciting toxicity to normal cells.     

Dye-Sensitized Solar Cell Based on a Blend of Hyperbranched Poly(aryl-ether-urethane) Electrolyte with TiO2 Nanoparticles

Hyperbranched poly(aryl-ether-urethane) is reported in this work as an efficient polymer electrolyte for photovoltaic application. Along with KI and I₂ as redox carriers in nanocrystalline dye-sensitized solar cell (DSC), this polymer yielded an overall conversion efficiency of 4.1%, upon illumination with visible light. The fabricated cell results in stable device performing under thermal stress maintaining about 70% of its initial value for 2 days in the direct atmosphere without sealing.     

A family of microporous materials formed by Sn(IV) phosphonate nanoparticles

Reaction of Sn(IV) with phosphonic acids results in the formation of tin phosphonates with a spherical morphology arising from the aggregation of nanosized individual particles. Under high magnification, the spheres are shown to be porous with surface areas of 200-515 m2/g, depending on the type of phosphonic acid and the synthesis conditions used. The pores are largely micro in nature but also somewhat dependent on the type of phosphonic acid utilized in the preparation. Both aliphatic and aromatic organic phosphonates form these spherical aggregates. Functional groups, such as amino and carboxyl, may be introduced as part of the phosphonic acid or subsequently by further reaction, leading to a large family of naturally formed nanoparticles with accompanying microporosity.     

Dynamics and internal stress at the nanoscale related to unique thermomechanical behavior in polymer nanocomposites

A small amount of alumina nanoparticles in polymethylmethacrylate causes a sharp depression of the glass transition temperature (Tg) accompanied by a toughening of the composite. We investigated this phenomenon using multispeckle x-ray photon correlation spectroscopy. Measurements reveal a dynamic structure factor that has the form exp[-(t/taua)beta], with beta greater than 1. We show for the first time that beta(T) tracks the internal stress at the polymer-particle interface. The internal stress, which we propose arises due to the entropic penalty that the polymer faces in the presence of the nanoparticles, engenders temporally heterogeneous dynamics. In the jammed glassy state, we show that the dominant fast relaxation mode--taumax--aided by a weak dewetting interface relieves the stress and follows the variations in Tg.     

Helical conformational specificity of enzymatically synthesized water-soluble conducting polyaniline nanocomposites

A novel template guided enzymatic approach has been developed to synthesize optically active conducting polyaniline (PANI) nanocomposites in the presence of H2O2 as an oxidant, using (+) and (-) 10-camphorsulfonic acid (CSA) as a dopant and chiral inductor. The formation of chiral polyaniline in the nanocomposites was confirmed by circular dichroism (CD). Interestingly, the CD spectra of nanocomposites formed either with (+) or with (-) CSA show the enzyme itself plays a critical role in controlling the stereospecificity of the polyaniline (PANI) in the nanocomposite. The enzyme used for the polymerization of aniline in the nanocomposite was horseradish peroxidase (HRP). It was shown that this enzyme prefers a specific helical conformation, regardless of whether induced chirality in the complex CSA-aniline is from (+) or (-) CSA. UV-vis spectra show that the polyaniline is in the conducting form, and transmission electron micrographs (TEM) show that the nanocomposites are dispersed nicely with particle size dimensions in the range of 20-50 nm. Electron diffraction patterns of these chiral polymer nanocomposites suggest that these nanocomposites are in both crystalline and amorphous states.     

Cool white light emission on Ca3−(l+n)MgSi2O8:\mathrm{Ce}_{\mathrm{l}}^{3+}, \mathrm{Eu}_{n}^{2+} phosphors and analysis of energy transfer mechanism

Rare earth ions (Ce³⁺, Eu²⁺) activated Ca₃MgSi₂O₈ (CMSO) phosphors have been synthesized using solid-state reaction method in 95%N₂+5%H₂ reduction atmosphere at elevated temperatures by varying Eu²⁺ concentration from 0.0075 to 0.0300 at the fixed Ce_0.03 concentration to study their photoluminescence (PL) properties. An energy transfer occurs from Ce³⁺ to Eu²⁺ through a significant overlap of Eu²⁺ excitation spectrum with Ce³⁺ emission spectrum in CMSO, together with the systematic relative decrease and increase in emission bands of Ce³⁺ and Eu²⁺, respectively, have been observed. To support the phenomenon, diffuse reflectance spectra show various absorption levels corresponding to Ce³⁺, Eu²⁺, and/or mixture of both rare earth ions. An optimum emission was realized at 0.0150 of Eu²⁺ via. energy transfer from Ce³⁺ ion. By utilizing the principle of energy transfer, the critical distance (R _c ) between activator ions was found to be 18.64 Å. The CIE chromaticity coordinates measured on the Ca₃MgSi₂O₈:Ce³⁺, Eu²⁺ phosphors excited under ultraviolet (365 nm) source shows the values lie in cool white light region could be applied to solid state lighting.     

A near-infrared emissive Al sensing platform for specific detection in solution,cells and probing DNase activity

A new tricarbocyanine-based chemosensor exhibited a dramatic Al³⁺-specific fluorescence turn-on response in the near-infrared (NIR) region. The receptor was found to be highly selective towards Al³⁺ over other metal ions in physiological condition. The sensor was non-toxic and could thus be employed as an imaging probe for detecting intracellular Al³⁺ in live cells. Interestingly, upon interaction with DNA in solution, the L–Al³⁺ ensemble rendered tracking of DNase activity in solution through a systematic reduction in the fluorescence emission intensity.     

Comparative analysis of premixed combustion and blending of alcohols with neem and wintergreen oil biofuel blends in CI engine

Journal of Thermal Analysis and Calorimetry - High-viscous neat neem oil (NO) with low-viscous wintergreen oil (WGO) may be used in diesel engines without any engine modification. Based on the...