Synthesis of Er2O3 blended CeO2 nanocomposites and investigation of their biomedical applications

A simple microwave irradiation technique has been used for the successful preparation of different weight percentages of Pure Er2O3, CeO2 nanoparticles (NPs), and CeO2 / Er2O3 heterostructured nanocomposites (NCs). X-ray diffraction (XRD), UV-Vis spectroscopy, Photoluminescence (PL), and Transmission electron Microcopy (TEM) were used to analyze the samples as they were prepared. X-ray diffraction patterns revealed well-crystallized Er2O3 and CeO2 nanoparticles powders in the cubic system respectively. The bandgaps of E1, E7C2, E5C5, E2C7, and C1 were calculated to be 2.55 eV, 2.41 eV, 2.40 eV, 2.23 eV, and 1.42 eV, respectively. Er2O3 blended CeO2 Nanocompositesshows excellent activity against bacteria (Bacillus sp and E. coli) and fungal (aspergillus, and mucor), further breast cancer cell line to reveal cytotoxic activity in biomedical applications

Principles of Magnetic Hyperthermia: A Focus on Using Multifunctional Hybrid Magnetic Nanoparticles

Hyperthermia is a noninvasive method that uses heat for cancer therapy where high temperatures have a damaging effect on tumor cells. However, large amounts of heat need to be delivered, which could have negative effects on healthy tissues. Thus, to minimize the negative side effects on healthy cells, a large amount of heat must be delivered only to the tumor cells. Magnetic hyperthermia (MH) uses magnetic nanoparticles particles (MNPs) that are exposed to alternating magnetic field (AMF) to generate heat in local regions (tissues or cells). This cancer therapy method has several advantages, such as (a) it is noninvasive, thus requiring surgery, and (b) it is local, and thus does not damage health cells. However, there are several issues that need to achieved: (a) the MNPs should be biocompatible, biodegradable, with good colloidal stability (b) the MNPs should be successfully delivered to the tumor cells, (c) the MNPs should be used with small amounts and thus MNPs with large heat generation capabilities are required, (d) the AMF used to heat the MNPs should meet safety conditions with limited frequency and amplitude ranges, (e) the changes of temperature should be traced at the cellular level with accurate and noninvasive techniques, (f) factors affecting heat transport from the MNPs to the cells must be understood, and (g) the effect of temperature on the biological mechanisms of cells should be clearly understood. Thus, in this multidisciplinary field, research is needed to investigate these issues. In this report, we shed some light on the principles of heat generation by MNPs in AMF, the limitations and challenges of MH, and the applications of MH using multifunctional hybrid MNPs

A Review of Biomass-Derived Heterogeneous Catalysts for Biodiesel Production

The scientific community is being forced to consider alternative renewable fuels such as biodiesel as a result of the sharp increases in the price of petroleum and the increased demand for petroleum-derived products. Transesterification is a technique used to create biodiesel where a variety of edible oils, non-edible oils, and animal fats are used. For this, either a homogeneous or heterogeneous catalyst is utilized. An appropriate catalyst is chosen based on the quantity of free fatty acid content in the oil. The main distinction between homogeneous and heterogeneous catalysts is that compared to the heterogeneous catalyst, the homogeneous catalyst is not affected by the quantity of free fatty acids in the oil. Early methods of producing biodiesel relied on homogeneous catalysts, which have drawbacks such as high flammability, toxicity, corrosion, byproducts such as soap and glycerol, and high wastewater output. The majority of these issues are solved by heterogeneous catalysts. Recent innovations use novel heterogeneous catalysts that are obtained from biomass and biowaste resources. Numerous researchers have documented the use of biomass-derived heterogeneous catalysts in the production of high-quality, pure biodiesel as a potentially greener manufacturing method. The catalysts were significantly altered through conventional physical processes that were both cost- and energy-effective. The present review is intended to analyze catalysts from biowaste for making biodiesel at a minimal cost. The most recent methods for creating diverse kinds of catalysts—including acidic, basic, bifunctional, and nanocatalysts—from various chemicals and biomass are highlighted in this review. Additionally, the effects of various catalyst preparation methods on biodiesel yield are thoroughly explored

Role of Magnetite Nanoparticles Size and Concentration on Hyperthermia under Various Field Frequencies and Strengths

Magnetite (Fe3O4) nanoparticles were synthesized using the chemical coprecipitation method. Several nanoparticle samples were synthesized by varying the concentration of iron salt precursors in the solution for the synthesis. Two batches of nanoparticles with average sizes of 10.2 nm and 12.2 nm with nearly similar particle-size distributions were investigated. The average particle sizes were determined from the XRD patterns and TEM images. For each batch, several samples with different particle concentrations were prepared. Morphological analysis of the samples was performed using TEM. The phase and structure of the particles of each batch were studied using XRD, selected area electron diffraction (SAED), Raman and XPS spectroscopy. Magnetic hysteresis loops were obtained using a Lakeshore vibrating sample magnetometer (VSM) at room temperature. In the two batches, the particles were found to be of the same pure crystalline phase of magnetite. The effects of particle size, size distribution, and concentration on the magnetic properties and magneto thermic efficiency were investigated. Heating profiles, under an alternating magnetic field, were obtained for the two batches of nanoparticles with frequencies 765.85, 634.45, 491.10, 390.25, 349.20, 306.65, and 166.00 kHz and field amplitudes of 100, 200, 250, 300 and 350 G. The specific absorption rate (SAR) values for the particles of size 12.2 nm are higher than those for the particles of size 10.2 nm at all concentrations and field parameters. SAR decreases with the increase of particle concentration. SAR obtained for all the particle concentrations of the two batches increases almost linearly with the field frequency (at fixed field strength) and nonlinearly with the field amplitude (at fixed field frequency). SAR value obtained for magnetite nanoparticles with the highest magnetization is 145.84 W/g at 765.85 kHz and 350 G, whereas the SAR value of the particles with the least magnetization is 81.67 W/g at the same field and frequency

Critical Perspective on the Industry-centred Engineering of Single-Crystalline Ni-rich Cathodes

Ever growth in the energy demand has catapulted us to explore various energies. Henceforth, to meet these ends, among the different cathode active materials, nickel (Ni) rich polycrystalline (PC) cathode materials have been known to serve the purpose aptly. Yet, these PC Ni-rich cathode materials have yielded inferior performances with an increase in voltage and temperature. The absence of grain boundaries in the intrinsic structure, high mechanical strength, high thermal stability, and controllable crystal faucet have made SC cathodes a better prospect. Yet, there are challenges to overcome in the SC cathodes, like larger crystals hindering the Li+ transport, which leads to disappointing electrochemical performance. Through this perspective article, we wish to elucidate the crucial factors that facilitate the growth of SC-NCM cathode, viable dopants, and coating materials that could enhance the performance, future scope, and scalability of SC-NCM at the Industrial level

Role of Magnetite Nanoparticles Size and Concentration on Hyperthermia under Various Field Frequencies and Strengths

Magnetite (Fe3O4) nanoparticles were synthesized using the chemical coprecipitation method. Several nanoparticle samples were synthesized by varying the concentration of iron salt precursors in the solution for the synthesis. Two batches of nanoparticles with average sizes of 10.2 nm and 12.2 nm with nearly similar particle-size distributions were investigated. The average particle sizes were determined from the XRD patterns and TEM images. For each batch, several samples with different particle concentrations were prepared. Morphological analysis of the samples was performed using TEM. The phase and structure of the particles of each batch were studied using XRD, selected area electron diffraction (SAED), Raman and XPS spectroscopy. Magnetic hysteresis loops were obtained using a Lakeshore vibrating sample magnetometer (VSM) at room temperature. In the two batches, the particles were found to be of the same pure crystalline phase of magnetite. The effects of particle size, size distribution, and concentration on the magnetic properties and magneto thermic efficiency were investigated. Heating profiles, under an alternating magnetic field, were obtained for the two batches of nanoparticles with frequencies 765.85, 634.45, 491.10, 390.25, 349.20, 306.65, and 166.00 kHz and field amplitudes of 100, 200, 250, 300 and 350 G. The specific absorption rate (SAR) values for the particles of size 12.2 nm are higher than those for the particles of size 10.2 nm at all concentrations and field parameters. SAR decreases with the increase of particle concentration. SAR obtained for all the particle concentrations of the two batches increases almost linearly with the field frequency (at fixed field strength) and nonlinearly with the field amplitude (at fixed field frequency). SAR value obtained for magnetite nanoparticles with the highest magnetization is 145.84 W/g at 765.85 kHz and 350 G, whereas the SAR value of the particles with the least magnetization is 81.67 W/g at the same field and frequency

Redox-active pigeon excreta mediated metal oxides nanosheets for enhancing co-catalyst for photovoltaic performance in dye-sensitized solar cells

Pigeon excreta (PE) contains a significant amount of organic components, which are harmful to the environment and humans. Hence, the proper disposal of PE deals with practical problems. Furthermore, using PE for other energy sources is an efficient innovation. In this study, an innovative technique was implemented for producing agglomeration free and distinct metal oxides using PE as a surfactant and capping agent. The different characterizations and their analysis explain the mechanism involved in forming distinct metal oxide nanosheets utilizing PE. The obtained samples were confirmed by the characteristic peaks of PE mediated metal oxides such as (NiO, Co3O4 and CuO) observed in X-ray diffraction (43.47°, 36.61° and 35.71°), and the UV-DRS band-gap narrowing (2.4, 2.13 and 2.02 eV). In the FTIR spectrum, it is clearly evident that there is a high amine group in the PE which plays a key role in reducing the agglomeration in the metal oxides. The morphology of PE mediated NiO, Co3O4 and CuO revealed nanoflakes and nanosheets like structures identified from FE-SEM analysis. The photovoltaic performance of the PE mediated metal oxides showed improved photocurrent conversion efficiencies of 1.2–1.6 times more than pure metal oxides. Among all, the CuO-PE had the most significant photovoltaic performance, with a photoconversion efficiency of 3.22 %. The reduction of I3− to 3I− along the counter electrode/electrolyte interaction is facilitated by the PE mediated transition metal oxides, as shown by the photocurrent response, Tafel plot and electrical impedance spectroscopy results, which were discussed in detail

Sustainable Synthesis of Bright Fluorescent Nitrogen-Doped Carbon Dots from <i>Terminalia chebula</i> for In Vitro Imaging

In this study, sustainable, low-cost, and environmentally friendly biomass (Terminalia chebula) was employed as a precursor for the formation of nitrogen-doped carbon dots (N-CDs). The hydrothermally assisted Terminalia chebula fruit-derived N-CDs (TC-CDs) emitted different bright fluorescent colors under various excitation wavelengths. The prepared TC-CDs showed a spherical morphology with a narrow size distribution and excellent water dispensability due to their abundant functionalities, such as oxygen- and nitrogen-bearing molecules on the surfaces of the TC-CDs. Additionally, these TC-CDs exhibited high photostability, good biocompatibility, very low toxicity, and excellent cell permeability against HCT-116 human colon carcinoma cells. The cell viability of HCT-116 human colon carcinoma cells in the presence of TC-CDs aqueous solution was calculated by MTT assay, and cell viability was higher than 95%, even at a higher concentration of 200 μg mL−1 after 24 h incubation time. Finally, the uptake of TC-CDs by HCT-116 human colon carcinoma cells displayed distinguished blue, green, and red colors during in vitro imaging when excited by three filters with different wavelengths under a laser scanning confocal microscope. Thus, TC-CDs could be used as a potential candidate for various biomedical applications. Moreover, the conversion of low-cost/waste natural biomass into products of value promotes the sustainable development of the economy and human society

Natural Nitrogen-Doped Carbon Dots Obtained from Hydrothermal Carbonization of Chebulic Myrobalan and Their Sensing Ability toward Heavy Metal Ions

Chebulic Myrobalan is the main ingredient in the Ayurvedic formulation Triphala, which is used for kidney and liver dysfunctions. Herein, natural nitrogen-doped carbon dots (NN-CDs) were prepared from the hydrothermal carbonization of Chebulic Myrobalan and were demonstrated to sense heavy metal ions in an aqueous medium. Briefly, the NN-CDs were developed from Chebulic Myrobalan by a single-step hydrothermal carbonization approach under a mild temperature (200 °C) without any capping and passivation agents. They were then thoroughly characterized to confirm their structural and optical properties. The resulting NN-CDs had small particles (average diameter: 2.5 ± 0.5 nm) with a narrow size distribution (1–4 nm) and a relatable degree of graphitization. They possessed bright and durable fluorescence with excitation-dependent emission behaviors. Further, the as-synthesized NN-CDs were a good fluorometric sensor for the detection of heavy metal ions in an aqueous medium. The NN-CDs showed sensitive and selective sensing platforms for Fe3+ ions; the detection limit was calculated to be 0.86 μM in the dynamic range of 5–25 μM of the ferric (Fe3+) ion concentration. Moreover, these NN-CDs could expand their application as a potential candidate for biomedical applications and offer a new method of hydrothermally carbonizing waste biomass

Recent Advancements of Polyaniline/Metal Organic Framework (PANI/MOF) Composite Electrodes for Supercapacitor Applications: A Critical Review

Supercapacitors (SCs), also known as ultracapacitors, should be one of the most promising contenders for meeting the needs of human viable growth owing to their advantages: for example, excellent capacitance and rate efficiency, extended durability, and cheap materials price. Supercapacitor research on electrode materials is significant because it plays a vital part in the performance of SCs. Polyaniline (PANI) is an exceptional candidate for energy-storage applications owing to its tunable structure, multiple oxidation/reduction reactions, cheap price, environmental stability, and ease of handling. With their exceptional morphology, suitable functional linkers, metal sites, and high specific surface area, metal–organic frameworks (MOFs) are outstanding materials for electrodes fabrication in electrochemical energy storage systems. The combination of PANI and MOF (PANI/MOF composites) as electrode materials demonstrates additional benefits, which are worthy of exploration. The positive impacts of the two various electrode materials can improve the resultant electrochemical performances. Recently, these kinds of conducting polymers with MOFs composites are predicted to become the next-generation electrode materials for the development of efficient and well-organized SCs. The recent achievements in the use of PANI/MOFs-based electrode materials for supercapacitor applications are critically reviewed in this paper. Furthermore, we discuss the existing issues with PANI/MOF composites and their analogues in the field of supercapacitor electrodes in addition to potential future improvements