Sol-gel Approach Research Articles

Tailoring of the Properties of Amorphous Mesoporous Titanosilicates Active in Acetone Condensation

Amorphous mesoporous materials are promising as catalysts for processes involving or forming bulk molecules. In a reaction such as acetone condensation to form mesitylene, an effective catalyst should not only have a developed porous structure but also have active centers of acidic and basic types. The sol–gel approach allows one to obtain titanosilicates with such characteristics. This work demonstrates the possibility of controlling their properties by varying the conditions for the synthesis of titanosilicate gels. It has been established that controlling hydrolysis allows one to increase the activity of amorphous mesoporous titanosilicates by 10 times: from acetone conversion of 6% to 60%. It has been shown that the use of titanium acetylacetonate complexes in the synthesis of gels leads to an increase in the content of tetracoordinated Ti in the structure and contributes to an increase in the acidity of titanosilicates. During the condensation of acetone on the obtained mesoporous titanosilicates, high acetone conversion (60–79%) and mesitylene selectivity of up to 83% were achieved.

A novel red emitting Eu3+ doped CaSiO3 nanophosphor derived from agro-wastes for advanced forensic applications

The modified sol–gel approach was utilised to synthesise Eu3+ (1–5 mol%) doped CaSiO3 nanophosphors (NPs) using eggshell (ES) and rice husk ash (RHA) as precursors for SiO2 and CaO, respectively. Powder X-ray diffraction (PXRD) peaks confirm the monoclinic structure of the powdered samples. The photoluminescence (PL) emission spectra display distinct emission peaks corresponding to Eu3+ ions. After optimizing the Eu3+ ion concentration, the highest intensity (CaSiO3:3Eu3+) was achieved at 3 mol%. As the concentration increased beyond this point, the emission intensity decreased due to concentration quenching (CQ). Temperature-dependent photoluminescence (TDPL) was investigated in the range of 303 to 443 K. The results demonstrated that emissions at elevated temperatures are significantly stronger than those at ambient temperature. TDPL studies revealed excellent thermal stability, with emission intensity remaining at 87.5 % even at 423 K. Additionally, the phosphor’s absolute sensitivity of 0.003 K−1 and relative sensitivity of 1.44 % K−1 highlight its strong potential for temperature sensing applications. The suitability of the phosphor for the powder dusting method in fingerprint (FP) detection on various surfaces was also assessed. Under 365 nm UV light, the CaSiO3:3Eu3+ phosphor clearly reveals the level 1–3 structure of LFPs.

High-Temperature Behavior of Pd/MgO Catalysts Prepared via Various Sol–Gel Approaches

A series of Pd/MgO catalysts based on nanocrystalline MgO were prepared via different sol–gel approaches. In the first two cases, palladium was introduced during the gel preparation, followed by drying it in supercritical or ambient conditions. In the third case, aerogel-prepared MgO was impregnated with an ethanol solution of Pd(NO3)2. The prepared catalysts differ in particle size and oxidation state of palladium. The catalytic performance and thermal stability of the samples were examined in a model reaction of CO oxidation at prompt thermal aging conditions. The as-prepared and aged materials were characterized by low-temperature nitrogen adsorption, UV-vis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and ethane hydrogenolysis testing reaction. The highest initial activity (T50 = 103 °C) was demonstrated by the impregnated sample, containing Pd0 particles of 3 nm in size. The lowest T50 value (215 °C) after aging at 1000 °C was demonstrated by the impregnated Pd/MgO-WI sample. The high-temperature behavior of the catalysts was found to be affected by the initial oxidation state and dispersion of Pd. Two deactivation mechanisms, such as the agglomeration of Pd particles and migration of small Pd species into the bulk of the MgO support with the formation of Pd-MgO solid solutions, were discussed.

A Machine Learning Assisted Non-Enzymatic Electrochemical Biosensor to Detect Urea Based on Multi-Walled Carbon Nanotube Functionalized with Copper Oxide Micro-Flowers.

Detecting urea is crucial for diagnosing related health conditions and ensuring timely medical intervention. The addition of machine learning (ML) technologies has completely changed the field of biochemical sensing, providing enhanced accuracy and reliability. In the present work, an ML-assisted screen-printed, flexible, electrochemical, non-enzymatic biosensor was proposed to quantify urea concentrations. For the detection of urea, the biosensor was modified with a multi-walled carbon nanotube-zinc oxide (MWCNT-ZnO) nanocomposite functionalized with copper oxide (CuO) micro-flowers (MFs). Further, the CuO-MFs were synthesized using a standard sol-gel approach, and the obtained particles were subjected to various characterization techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectroscopy. The sensor's performance for urea detection was evaluated by assessing the dependence of peak currents on analyte concentration using cyclic voltammetry (CV) at different scan rates of 50, 75, and 100 mV/s. The designed non-enzymatic biosensor showed an acceptable linear range of operation of 0.5-8 mM, and the limit of detection (LoD) observed was 78.479 nM, which is well aligned with the urea concentration found in human blood and exhibits a good sensitivity of 117.98 mA mM-1 cm-2. Additionally, different regression-based ML models were applied to determine CV parameters to predict urea concentrations experimentally. ML significantly improves the accuracy and reliability of screen-printed biosensors, enabling accurate predictions of urea levels. Finally, the combination of ML and biosensor design emphasizes not only the high sensitivity and accuracy of the sensor but also its potential for complex non-enzymatic urea detection applications. Future advancements in accurate biochemical sensing technologies are made possible by this strong and dependable methodology.

Sol-Gel Pt-VO2 Films as Selective Chemoresistive and Optical H2 Gas Sensors.

In this work, VO2 (M1/R) thin films were exploited as H2 gas sensors. A flat film morphology, obtained by furnace annealing, was compared with a laser-induced nanostructured one. The combination of the environmentally friendly sol-gel approach with the ultrafast laser crystallization allows for significant reductions in energy consumption and related emissions during the fabrication of VO2 sensors. By decorating the sensors' surface with Pt nanoparticles (NPs), the sensor response was enhanced exploiting the hydrogen spillover effect. The Pt/VO2 sensors, tested at operating temperatures between 20 and 200 °C and for concentration of H2 from few ppm to 50000 ppm, offered a dual chemoresistive and optical sensing mode. Low operating temperatures of 150 °C were achieved, along with a detection limit as low as 2 ppm and a perfect baseline recovery. Both sensors guaranteed specific selectivity toward H2, without response to NO2 or humidity, and long-term stability over 500 h. The H2 sensing mechanism, for both the monoclinic and rutile VO2 phases, was investigated through in operando X-ray Diffraction and in situ X-ray Photoelectron Spectroscopy tests. The interaction was found to be based on the reversible formation of HxVO2 bronze, along with the reversible variations in the oxidation state of V.

3D Printing of Biocompatible and Antibacterial Silica-Silk-Chitosan-Based Hybrid Aerogel Scaffolds Loaded with Propolis.

The aim of this study is to design a therapeutic enhanced three-dimensional (3D) silk fibroin (SF)-based scaffold containing propolis (Ps)-loaded chitosan (CH) nanocarriers. To this aim, we initially synthesized a hybrid gel-based ink by a synergistic sol-gel and self-assembly approach and then processed the resulting gels by microextrusion-based 3D printing followed by supercritical drying to obtain 3D hybrid aerogel scaffolds. Ps was utilized to enhance the final scaffold's bactericidal efficacy and cell responsiveness. For the synthesis of the scaffold, two Ps loading methods (in preprint and postprinting steps) were investigated in order to optimize the Ps drug quantities in the scaffold and maximize the antibacterial properties of scaffold. In the postprinting Ps loading step, the hybrid silica-oxidized SF (SFO)-CH hydrogel ink was 3D printed into a construct with an interconnected porous structure, and then, Ps was loaded into the printed construct. In the preprint loading method, PS was incorporated into the SF and a hydrolyzed silane solution prior to gelation. The morphological studies demonstrate that the addition of Ps encapsulated CH nanoparticles (NPs) into the hydrogel solution improved the porosity of the developed scaffolds. The rheological analysis of the designed gel ink with and without Ps loading and the release kinetics were studied. The antimicrobial results show that the Ps-loaded scaffolds in the postprinting step exhibited superior antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) strains compared to a preprinted Ps-loaded scaffold. Direct and indirect in vitro cytotoxicity tests also confirmed the designed Ps-loaded scaffold biocompatibility toward a mouse fibroblast (L929) cell line. We demonstrated that the scaffold formulated by propolis-loaded chitosan NPs can enhance the migration and proliferation of L929 fibroblast cells. The obtained results prove the promise of the designed 3D printed silica-SFO-CH-Ps scaffolds as a potent 3D scaffold to mediate tissue regeneration but also as an antibacterial highly porous matrix to support wound healing.

Preparation of zirconium hydrogen phosphate coatings on alkali thermal titanium via a one-step sol–gel method to improve the friction resistance, bioactivity, and osteogenic potential

Titanium implants are widely used in dental restorations for patients suffering from dentition defects. However, the biologically inert of Ti, poor osteoinduction properties and the release of Ti particles due to friction between the bone and the implants can inhibit osseointegration and adversely affect the success rate of implantation. In this study, a zirconium phosphate (ZrP) coating was constructed on the surface of alkali thermal titanium (AT-Ti) via a one-step sol–gel approach. Subsequently, the friction resistance, bioactivity, and osteogenesis properties of the prepared coating were studied. The surface characterization results confirmed that AT-Ti was successfully coated with amorphous ZrP, and ZrP modification was found to effectively reduce the friction rate. In addition, the surface morphology after friction test was smoother. In terms of the bioactivity, the presence of a phosphate group in the ZrP coating led to the effective enrichment of Ca2+ to promote the formation of hydroxyapatite (HAp). It was also discovered that ZrP exhibited an excellent performance in cell viability and mineralization experiments, in addition to up-regulating the expression of osteogenesis related genes. Overall, ZrP modification of AT-Ti leads to an excellent friction resistance, bioactivity, and osteoinductive properties, thereby indicating its broad application prospects in implant therapy.

Synthesis, analysis and characterization of surfactant-assisted TiO2 nanoparticles for ammonia gas sensor applications

In our study, we focused on gas sensing, particularly ammonia detection. We synthesized and examined three types of nanoparticles: pure and conducting polymer-based TiO2 nanoparticles. The nanoparticles were prepared by an easy sol-gel approach. All of the samples were characterized using XRD, FTIR, UV-vis, FESEM, EDAX and BET. Gas sensing measurements were carried out for each sample. Among them, PEG-TiO2 stood out with remarkable gas sensing abilities, distinguishing it from other gas detection technologies. We thoroughly investigated the sensor performance, focusing close scrutiny to metrics such as response and recovery times. The greatest reduction in response time and recovery time (95 s / 123 s) was achieved at 25 ppm. These metrics provide insights into how quickly the sensor detects and recovers from the presence of the target gas. Our findings offer important insights for optimizing the sensor performance of PEG-TiO2, highlighting its remarkable gas sensing capabilities.

An overview of the optical and magnetic properties of Ba0.6Cd0.4TiO3 micro rods prepared by the facile sol-gel approach for spintronic applications

An overview of the optical and magnetic properties of Ba0.6Cd0.4TiO3 micro rods prepared by the facile sol-gel approach for spintronic applications

Structural, electrical and magnetic studies on Zn doped MnFe2O4 nanoparticles with via Sol-Gel approach

A manganese ferrite (MnFe2O4) nanoparticle is prepared through sol-gel method. The various concentration of Zn (x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9) was added to the initial solutions. Through X-Ray diffraction examinations results confirmed the cubic spinel structure of Mn1-xZnxFe2O4 and have larger crystallite size. The functional analysis is obtained through Fourier transform infrared spectroscopy (FTIR) analysis and it is indicated that Fe-O, Mn-O, and Zn-O vibrational bands. The optical analysis carried out through UV–visible spectrometer. The surface features with morphology and its content of elements in the samples were found through scanning electron microscope (SEM) with energy dispersive (EDAX) analysis. The energy analysis carried out through Xray Photo electro absorption (XPS) analysis. The detailed magnetic characteristics of the resulting samples such as cohersivity (Hc), magnetization (Ms), retentivity (Hr), squareness ratio (SQR) and anisotripic constant (Ki) were found through vibrating sample magnetometer (VSM), shows good magnetic property, multi grain wall and the strong dependents of Zn . The dielectric related parameters like dielectric constant for real and imaginary components, loss tangent with AC conductivity with respect to applied frequency are enhanced dielectric constant and at the same time it reduces the dielectric loss tangent discussed through LCR measurement. The electrochemical behaviour of the samples was tested through cyclic voltameter setup. Finally, concluded with their merits and demerits.

Novel CoFe2O4 / LaAlO3 nanocomposites: An impressive photocatalyst with p-n hetero-junction for improved H2 generation under visible exposure

The present work is devoted to the synthesis of perovskite LaAlO3 by Sol-Gel approach and its application for the photo-evolution of H2 in conjunction with cobalt ferrite CoFe2O4 prepared by nitrate route. The thermal analysis (TG/DSC) showed that the formation is completed at 600 °C. The X-ray diffraction (XRD) pattern is characteristic of a single phase, crystallizing in a rhombohedral symmetry with a crystallite size of 36 nm. The SEM micrographs revealed a homogeneous structure with an agglomeration of shaped grains (40–80 nm). The forbidden band (3.39 eV), calculated from diffuse reflectance data, is assigned to the ligand charge transfer O2−: 2p → Al3+: 3s orbital. As prepared, LaAlO3 is an n-type semiconductor as demonstrated from the capacitance - potential (C−2 - E) graph with an electron density of 9.4 × 1014 cm−3 due to oxygen under-stoichiometry. Attention was directed to photo-electrochemistry in connection with water reduction into hydrogen. With a negative conduction band potential (−0.11 VSCE), H2 generation can be synergized over the hetero-system by visible light. The photocatalytic capability of CoFe2O4 25%/LaAlO3 revealed a high H2 generation of 963 μmol g−1 in the alkaline electrolyte (NaOH, 0.1 M) with a catalyst dose of 1 mg mL−1, which is 1.3 times more than CoFe2O4 under similar conditions. Photoactivity is significantly improved by 60%, up to 2400 μmol g−1 in the presence of oxalate C2O42− as a hole scavenger in the hetero-junction, two hydrogen release tests were successfully recorded. The higher H2 production in the hetero-junction system is attributed to the lower recombination rate of electron/hole (e−/h+) in the material, due to the large band bending at the solid interfacial.

Simplified synthesis and identification of novel nanostructures consisting of cobalt borate and cobalt oxide for crystal violet dye removal from aquatic environments

Crystal violet dye poses significant health risks to humans, including carcinogenic and mutagenic effects, as well as environmental hazards due to its persistence and toxicity in aquatic ecosystems. This study focuses on the efficient removal of crystal violet dye from aqueous media using novel Co3O4/Co3(BO3)2 nanostructures synthesized via the Pechini sol–gel approach. The nanostructures, which were abbreviated to EN600 and EN800, were fabricated at calcination temperatures of 600 and 800 °C, respectively. X-ray diffraction (XRD) analysis revealed that the synthesized samples have a cubic Co3O4 phase and an orthorhombic Co3(BO3)2 phase, with mean crystal sizes of 43.82 nm and 52.93 nm for EN600 and EN800 samples, respectively. The Brunauer–Emmett–Teller (BET) surface areas of EN600 and EN800 samples were 65.80 and 43.76 m2/g, respectively, indicating a significant surface area available for adsorption. Optimal removal of crystal violet dye was achieved at a temperature of 298 K, a contact time of 70 min, and a pH of 10. The maximum adsorption capacities were found to be 284.09 mg/g for EN600 and 256.41 mg/g for EN800, which are notably higher compared to many conventional adsorbents. The adsorption process followed the pseudo-second-order kinetic model and fitted well with the Langmuir isotherm. The adsorption was exothermic, spontaneous, and physical in nature. Moreover, the adsorbents exhibited excellent reusability, retaining high efficiency after multiple regeneration cycles using 6 mol/L hydrochloric acid. These findings highlight the potential of these Co3O4/Co3(BO3)2 nanostructures as effective and sustainable materials for water purification applications.

Reactive Blue MEBF 222 dye and textile wastewater treatment using metal-doped cobalt and nickel perovskites by batch and column adsorption process.

Water contamination is a serious issue that has an impact on the whole globe. In the current work, adsorption technique was used to remove synthetic Reactive Blue MEBF 222 textile dye utilizing Cd-doped Co (Co1-xCd1.5xFeO3), Zn-doped Co (Co1-xZn1.5xFeO3), Cr-doped Co (Co1-xCr1.5xFeO3), Zn-doped Ni (Ni1-xZn1.5xFeO3), and Cr-doped Ni (Ni1-xCr1.5xFeO3) perovskites, synthesized by sol-gel auto-combustion approach. According to the findings of batch adsorption studies, maximum adsorption was observed at pH 3 (45.62mg/g), 0.01g/50ml dosage (36.67mg/g), 60min (14.31mg/g), 100ppm dye concentration (47.41mg/g), and 308K (35.96mg/g) for Co1-xCd1.5xFeO3; at 3 pH (42.94mg/g), 0.01g/50ml dosage (35.33mg/g), 60min (12.88mg/g), 100ppm dye concentration (40.52mg/g), and 308K (31.31mg/g) for Co1-xZn1.5xFeO3; at 2 pH (38.82mg/g), 0.01g/50ml dosage (32.20mg/g), 60min (11.98mg/g), 100ppm dye concentration (33.54mg/g), and 308K (29.34mg/g) for Co1-xCr1.5xFeO3; at 2 pH (34.97mg/g), 0.01g/50ml dosage (30.41mg/g), 60min (10.46mg/g), 100ppm dye concentration (27.19mg/g), and 308K (26.12mg/g) for Ni1-xZn1.5xFeO3; and at 2 pH (31.22mg/g), 0.01g/50ml dosage (25.04mg/g), 60min (9.48mg/g), 100ppm dye concentration (21.73mg/g), and 308K (23.61mg/g) for Ni1-xCr1.5xFeO3. The pseudo-second-order model showed good fitness for adsorption kinetic data. Electrolytes, detergents/surfactants, and heavy metal ions had a substantial impact on the adsorption potential. The column adsorption experiments demonstrated optimal bed height, flow rate, and intake dye concentration to be 3cm, 1.8ml/min, and 70mg/l, respectively, in the column experiment. With an adsorption capacity of 44.1mg/g, reactive blue (RB) 222 dye was able to achieve its maximum adsorption. Detailed desorption of RB 222 dye was also achieved. The novelty of this adsorption method lies in its eco-friendliness, ease of handling, and cost-effectiveness.

Surface-doped perovskite electrolyte for low-temperature ceramic electrochemical cells

Protonic ceramic electrochemical cells (PCECs) can be employed for power generation and sustainable hydrogen production. Lowering the PCEC operating temperature to >500 °C can facilitate its scale-up and commercialization. However, achieving high energy efficiency and long-term durability at low operating temperatures is a long-standing challenge. Here, we report a simple and scalable approach for fabricating metal ion doping into perovskite (Li-doped SrTiO3 (STO)) using the sol-gel approach and presented as a proton conducting electrolyte with lower ohmic and polarization resistance for low-temperature ceramic fuel cells. The prepared electrolyte with symmetrical electrodes attains high power densities in fuel-cell mode (∼0.65 W cm−2 at 520 °C and ∼0.20 W cm−2 at 420 °C) and exceptional current densities in steam electrolysis mode (−0.94 A cm−2 at 1.4 V and 520 °C). Additionally, five-layer devices (Ni-NCAL/BCZYYb/Li-STO/BCZYYb/NCAL-Ni) demonstrate the proton fuel cell performance of 0.55 W cm−2 at 520 °C.

Engineering Oxygen Vacancies of Co-Mn-Ni-Fe-Al High-Entropy Spinel Oxides by Adjusting Co Content for Enhanced Catalytic Combustion of Propane.

Transition metal-based oxides with similar oxidation activities for catalytic hydrocarbon combustion have attracted much attention. In this study, a new class of metal high-entropy oxides (CoxMnNiFeAl)3O4 (x = 1, 2, 3, 4, 5) with a porous structure was fabricated through a simple and inexpensive NaCl template-assisted sol-gel approach, which was employed for the catalytic oxidation of propane. The results indicated that the content of cobalt has a great impact on its activity, and the (Co4MnNiFeAl)3O4 catalyst exhibited the best catalytic activity. At the high space velocity of 60 000 mL·g-1·h-1, the optimized one with high-temperature treatment can still achieve 90% propane conversion at 309 °C, which is 68 and 178 °C lower than those of the (CoMnNiFeAl)3O4 catalyst and pure cobalt oxide, respectively. Meanwhile, it has the lowest apparent activation energy (46.6 KJ·mol-1) and the fastest reaction rate (26.976 × 10-6 mol·gcat-1·s-1 at 290 °C). The improved performance of the (Co4MnNiFeAl)3O4 catalyst could be attributed to the enhancement of low-temperature reducibility, the increased number of reactive surface oxygen species, and the cocktail effect of the high-entropy oxides. This work provides new insights into the preparation of efficient light alkane degradation catalysts and a realistic approach for the large-scale application of high-entropy oxides in the field of oxidation catalysts.

High Throughput Manufacturing of Highly Ordered Mesoporous Thin Film Oxides for Hybrid-Polymer Nanocomposite Dielectrics

Highly ordered mesoporous metal oxide thin films have potential to become integrated into widely impactful dielectric materials due to the tunable properties of the oxide and its polymer filling; however, current manufacturing techniques to form the mesoporous oxide greatly limit scalable fabrication. Sol-gel mesoporous metal oxides generated via traditional processes require multi-day aging and high temperature, prolonged curing processes to yield controlled porosity at the expense of manufacturability. Moreover, high cost and unstable alkoxide precursors require precision over the solution precursor pH and subsequent thin film aging humidity after deposition.Solution combustion synthesis (SCS) is a next-generation method of generating metal oxides at reduced process temperatures (often <300 ºC) and using green precursors compared to the sol-gel approach. The metal oxide is typically produced from a metal nitrate, which provides both the metal cation and oxidant and an organic chelator fuel. The fuel acts to stabilize the cation against hydrolysis and to participate in the exothermic redox reaction that results in the metal oxide.Here, we present porogen integrated rapid oxidation (PIRO) which utilizes the principles of SCS to fabricate large-area mesoporous thin films of AlOx in less than 1 hour and at a temperature of 230 ºC. The PIRO method uses low-cost precursors to generate micelles with a controllable open-cell porosity ranging from ~30 – 60% and with varying degrees of closed-packed cubic ordering at a nearly 95% reduction in overall processing time. We show the precursor chemistry can be deposited via ultrasonic spray or blade coating at up to 6 m/min to manufacture large area mesoporous oxides and demonstrate filling of the porous AlOx with TOPAS® polymer to generate a hybrid nanocomposite with a dielectric constant of 6.26.

Tailoring the stress-free two-way shape memory effect in sol–gel crosslinked poly(ϵ-caprolactone)-based semicrystalline networks

Two-way shape memory polymers are stimulus-responsive materials capable of changing their shape between two configurations based on an on/off thermal stimulus. While the traditional effect has been studied under the application of an external mechanical load, it was demonstrated also in the absence of an external load. Such a response only relies on a carefully tailored macromolecular architecture of the polymer combined with a specific thermo-mechanical protocol. In particular, semicrystalline networks, either consisting of a multi-phase copolymer network or a homopolymer based network with broad phase transitions, have been proposed to this aim under ad hoc thermo-mechanical histories. In this work, the two-way shape memory behavior is studied on a poly(ϵ-caprolactone)-based network, crosslinked by means of a sol–gel approach and tailored on the selection of the molecular weight of the precursor polymer. Changing the prepolymer precursor allowed to tune the melting/crystallization regions of the networks, thus the thermal region of the reversible shape memory effect. The application of properly designed thermo-mechanical cycles allowed to study the two-way shape memory effect without the application of an external load under tensile conditions. Given a specific network, the stress-free actuation of the reversible elongation-contraction cycle under tensile conditions was induced across its specific melting/crystallization region. The extent of the effect was found to depend on the crystalline fraction remaining for the given actuation temperature and on the tensile stretched state imposed on the materials during the training step. The results were compared with the response achieved under the traditional two-way shape memory protocol under stress. The stress-free two-way shape memory effect was also successfully demonstrated and emphasized, under flexural conditions, which suggests the potential of these materials as intrinsically reversible actuators, promising for applications in the biomedical field and/or for soft robotics.

Superparamagnetic Fe3O4 nanoparticles capped with silver induce apoptosis of colon cancer cells via damaging DNA@increasing ROS

A sol-gel approach was used to create magnetite nanoparticles (Fe3O4 NPs) as a core and silver (Ag) as a shell. Ag-Fe3O4 NPs were identified by x-ray diffraction (XRD) and energy dispersive x-ray (EDX), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and vibrating sample magnetometer (VSM) techniques. The capabilities of Ag-Fe3O4 NPs to induce apoptosis were investigated utilizing the Acridine orange/Ethidium bromide stain. The activity of NPs against (HT-29) cancer cells was further evaluated in and out of the existence of near-infrared (NIR) laser beam and alternating magnetic field (AMF). The exposed laser enhanced the cytotoxicity effect against (HT-29) cells. However, greatly elevated cytotoxic activity was seen with using the AMF.

Sol-Gel Synthesis of TiO2 with Pectin and Their Efficiency in Solar Cells Sensitized by Quantum Dots.

In this study, titanium oxide TiO2 nanoparticles were produced using the sol-gel approach of green synthesis with pectin as the reducing agent. The synthetized TiO2 nanoparticles with pectin were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), visible light absorption (UV-Vis) and the BET method. The structure and morphology of the TiO2 powder were described with SEM, revealing uniform monodisperse grains with a distribution of 80% regarding sizes < 250 nm; the resulting crystal phase of synthetized TiO2 was identified as an anatase and rutile phase with a crystallinity size estimated between 27 and 40 nm. Also, the surface area was determined by nitrogen adsorption-desorption using the Brown-Emmet-Teller method, with a surface area calculated as 19.56 m2/g, typical of an IV type isotherm, indicating mesoporous NPs. UV-Vis spectra showed that sol-gel synthesis reduced the band gap from the 3.2 eV common value to 2.22 eV after estimating the optical band gap energy using the adsorption coefficient; this translates to a possible extended photo response to the visible region, improving photoactivity. In addition, the power conversion of the photoelectrode was compared based on similar assembly techniques of TiO2 electrode deposition. Quantum dot crystals were deposited ionically on the electrode surface, as two different paste formulations based on a pectin emulsifier were studied for layer deposition. The results confirm that the TiO2 paste with TiO2-synthesized powder maintained good connections between the nanocrystalline mesoporous grains and the deposited layers, with an efficiency of 1.23% with the transparent paste and 2.27% with the opaque paste. These results suggest that pectin could be used as a low-cost, functional sol-gel catalysis agent for the synthesis of controlled NPs of metal oxide. It demonstrates interesting optical properties, such as an increase in photo response, suggesting further applications to photocatalysts and biomedical features.

Sol-gel derived ZnO film as a gas sensor: Influence of UV processing versus a thermal annealing

While preparing oxide layers as gas sensors by a sol-gel approach, a high-temperature annealing makes a challenge to apply in numerous applications like flexible electronics with a heavy influence on the oxide microstructure. Therefore, its replacing by UV irradiation combined with a mild heating as “photo-annealing” paves the way to develop soft protocols when designing oxide-based gas sensors bearing a fine nanocrystallinity. Herein, we consider hierarchical sol-gel derived ZnO films which were a subject of conventional annealing and photoannealing to compare their gas-sensor performance when exposed to alcohol vapors. It is found that films obtained by photoannealing have an X-ray amorphous character, in contrast to ones being thermally annealed; although, the hierarchical organization of both samples revealed by SEM is almost identical. The DFTB modeling performed for ZnO crystal exposed to alcohol molecules and water has indicated the chemiresistive effect to be enhanced with a molecular weight of analytes. These observations were validated in experiment with sol-gel ZnO layers which exhibited an alcohol response in sub-ppm concentration range down to 10 ppb. To selectively compare the impact of various alcohols, we successfully applied a linear-discriminant analysis to the vector signal of the on-chip multisensor array.