Self-assembly of the porphyrin monomer on the surface of Fe/graphene material: a novel sensing material for the detection of chloramphenicol antibiotic in aqueous solution.

Currently, electrochemical sensors are in the process of being developed and widely used in various fields, and new materials are being explored to enhance the precision and selectivity of the sensors. The Fe/graphene nanoparticles were synthesized utilizing a green approach, wherein leaf extract was employed as the reducing agent. The resulting materials underwent comprehensive characterization utilizing a range of contemporary techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. The findings of the study revealed that the nanocomposites of Fe/graphene/porphyrin comprised zero-valent iron nanoparticles, exhibiting an average particle size ranging from 15 to 60 nm. These nanoparticles were seen to be evenly dispersed across the graphene sheets. The presence of nanostructure porphyrin nanofibers, measuring 20 nm in diameter, was also shown to exhibit strong integration with the surface of the Fe/graphene nanomaterials. The electrochemical properties of the Fe/graphene/porphyrin nanocomposite were also investigated, demonstrating that the prepared material could be effectively employed as a sensing electrode in the electrochemical sensor for detecting Chloramphenicol (CAP) through CV, EIS, and DPV techniques using a three-electrode electrochemical system. Under optimal conditions, Fe/graphene/porphyrin exhibited a high current response when detecting CAPs.

Fabrication of a Reflective Optical Imaging Device for Early Detection of Breast Cancer.

This work presented the design and fabrication of a blood vessel and breast tumor detection device (BKA-06) based on optical energy spectroscopy. The BKA-06 device uses red-to-near-infrared light-emitting diodes that allow physicians or physicians to visualize blood vessels and surface structures such as breast tumors with the naked eye. The device consists of a built-in current control circuit to have the appropriate brightness (maximum illuminance of 98,592 lux) for the examination of superficial tumors deep under the skin, with a scan time of 3-5 min. The device BKA-06 can facilely observe each layer of blood vessels at the depth of the skin. For breast tumors, the location, size, and invasive areas around the tumor can also be visualized with the naked eye using the BKA-06 sensor. The results show that the BKA-06 sensor can provide clear breast tumor and vascular images, with a penetration of up to 15 cm in the skin and tissue layers of the breast. The breast tumor scanning tests with the BKA-06 sensor gave patients quick results and compared them through cell biopsy and MRI, respectively. The device has the advantages of being simple and easy to use, providing potential practical applications in the medical field and reducing costs for patients when taking MRI or CT scans. Therefore, the BKA-06 device is expected to help doctors and medical staff overcome difficulties in infusion, as well as identify breast tumors to support early breast cancer diagnosis and treatment.

Fabrication of Antibacterial Ag/Graphene-Integrated Non-woven Polypropylene Textile for Air Pollutant Filtering.

Air pollution and infectious diseases (such as the COVID-19 pandemic) have attracted considerable attention from governments and scientists worldwide to find the best solutions to address these issues. In this study, a new simultaneous antibacterial and particulate matter (PM) filtering Ag/graphene-integrated non-woven polypropylene textile was fabricated by simply immersing the textile into a Ag/graphene-containing solution. The Ag/graphene nanocomposite was prepared by reducing Ag ions on the surface of graphene nanoplatelets (GNPs) using the leaf extract. The prepared Ag/graphene textile was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Energy Dispersive X-ray (EDX), and contact angle measurements. The results showed excellent integration of the Ag/GNP nanocomposite into the non-woven polypropylene textile matrix. The prepared textile exhibited superhydrophobicity with a contact angle of 152°. The maximum PM removal percentage of the Ag/GNP-integrated textile was determined to be 98.5% at an Ag/GNP content of 1.5% w/w and a silicon adhesive of 1% w/w. The Ag/GNP textile exhibited high antibacterial activity toward Escherichia coli with no sign of bacteria on the surface. Remarkably, the as-prepared Ag/GNP textile was highly durable and stable and could be reused many times after washing.

Ultrasonic-Assisted Fabrication of MIL-100(Fe) Metal-Organic Frameworks as a Carrier for the Controlled Delivery of the Chloroquine Drug.

Metal-organic framework materials (MOFs) are materials with an ordered crystalline structure and high porosity that have been intensively investigated for many applications, such as gas adsorption, catalysis, sensors, drug delivery, and so on. Among them, the MOF-based drug delivery system has received increasing interest from scientists worldwide. This work presented the preparation of the MIL-100(Fe) metal-organic framework from the organic ligand of trimesic acid and iron ions with ultrasonic assistance. Scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area (BET), X-ray diffraction (XRD), infrared spectroscopy (FTIR), and Raman spectroscopy were employed to characterize the prepared MIL-100(Fe) material. MIL-100(Fe) materials synthesized by the ultrasonic method have uniform particle morphology ranging from 100 to 300 nm with a surface area of 1033 m2/g. The prepared MIL-100(Fe) was employed as a carrier for delivering chloroquine drug with a maximal loading capacity of 220 mg/g. The MIL-100(Fe)@chloroquine system was also characterized in detail. The delivery system's slow drug release was studied, showing that nearly 80% of chloroquine molecules were released after 7.5 h of immersing time in PBS and simulated gastric solutions and completely detached from the MIL-100(Fe)@chloroquine system only after approximately 80 h. This result shows the ability to control chloroquine drug release of the material, reducing the possibility of drug shock.

Applying response surface methodology to optimize partial nitrification in sequence batch reactor treating salinity wastewater.

In this study, the operation parameters of a partial nitrification process (PN) treating saline wastewater were optimized using the Box-Behnken design via the response surface methodology (BBD-RSM). A novel strategy based on the control of the carbon/nitrogen ratio (C/N), alkalinity/ammonia ratio (K/A), and salinity in three stages was used to achieve PN in a sequence batch reactor. The results demonstrated that a high and stable PN was completed after 50 d with an ammonia removal efficiency (ARE) of 98.37 % and nitrite accumulation rate (NAR) of 85.93 %. Next, BBD-RSM was applied, where ARE and NAR were the responses. The highest responses from the confirmation experiment were 99.9 % ± 0.04 and 95.25 % ± 0.32 when the optimum C/N, K/A, and salinity were identified as 0.84, 2, and 5.5 (g/L), respectively. The results were higher than those for the nonoptimized reactor. The developed regression model adequately forecasts the PN performance under optimal conditions. Therefore, this study provides a promising strategy for controlling the PN process and shows how the BBD-RSM model can improve the PN performance.

Fabrication of Porous Fe-Based Metal-Organic Complex for the Enhanced Delivery of 5-Fluorouracil in In Vitro Treatment of Cancer Cells.

Metal-organic complexes are one of the most studied materials in the last few decades, which are fabricated from organic ligands and metal ions to form robust frameworks with porous structures. In this work, iron-1,4-benzenedicarboxylic-polyethylene glycol (Fe-BDC-PEG) with a porous structure was successfully constructed by an iron(III) benzene dicarboxylate and polyethylene glycol diacid. The drug-delivery properties of the resultant Fe-BDC-PEG were tested for the loading and release of the 5-fluorouracil compound. The maximal loading capacity of Fe-BDC-PEG for 5-fluorouracil was determined to be 348.22 mg/g. The drug release of 5-fluorouracil-loaded Fe-BDC-PEG after 7 days was 92.69% and reached a maximum of 97.52% after 10 days. The 7 day and acute oral toxicity of Fe-BDC-PEG in mice were studied. The results show that no reasonable change or mortality was observed upon administration of Fe-BDC-PEG complex in mice at 10 g/kg body weight. When the uptake of Fe-BDC-PEG particles in mice was continued for 7 consecutive days, the mortality, feed consumption, body weight, and daily activity were negligibly changed.

Density Functional Study of Size-Dependent Hydrogen Adsorption on Ag n Cr (n = 1-12) Clusters.

Increasing interest has been paid for hydrogen adsorption on atomically controlled nanoalloys due to their potential applications in catalytic processes and energy storage. In this work, we investigate the interaction of H2 with small-sized Ag n Cr (n = 1-12) using density functional theory calculations. It is found that the cluster structures are preserved during the adsorption of H2 either molecularly or dissociatively. Ag3Cr-H2, Ag6Cr-H2, and Ag9Cr-H2 clusters are identified to be relatively more stable from computed binding energies and second-order energy difference. The dissociation of adsorbed H2 on Ag2Cr, Ag3Cr, Ag6Cr, and Ag7Cr clusters is favored both thermodynamically and kinetically. The dissociative adsorption is unlikely to occur because of a considerable energy barrier before reaching the final state for Ag4Cr or due to energetic preferences for n = 1, 5, and 8-12 species. Comprehensive analysis shows that the geometric structure of clusters, the relative electronegativity, and the coordination number of the Cr impurity play a decisive role in determining the preferred adsorption configuration.

Dioctyl Phthalate-Modified Graphene Nanoplatelets: An Effective Additive for Enhanced Mechanical Properties of Natural Rubber.

Graphene has been extensively considered an ideal additive to improve the mechanical properties of many composite materials, including rubbers, because of its novel strength, high surface area, and remarkable thermal and electron conductivity. However, the pristine graphene shows low dispersibility in the rubber matrix resulting in only slightly enhanced mechanical properties of the rubber composite. In this work, graphene nanoplatelets (GNPs) were modified with dioctyl phthalate (DOP) to improve the dispersibility of the graphene in the natural rubber (NR). The distribution of the DOP-modified GNPs in the NR matrix was investigated using scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The effect of the modified GNPs' contents on the mechanical properties of the GNPs/NR composite was studied in detail. The results showed that the abrasion resistance of the graphene-reinforced rubber composite significantly improved by 10 times compared to that of the rubber without graphene (from 0.3 to 0.03 g/cycle without and with addition of the 0.3 phr modified GNPs). The addition of the modified GNPs also improved the shear and tensile strength of the rubber composite. The tensile strength and shear strength of the NR/GNPs composite with a GNPs loading of 0.3 phr were determined to be 23.63 MPa and 42.69 N/mm, respectively. Even the presence of the graphene reduced the other mechanical properties such as Shore hardness, elongation at break, and residual elongation; however, these reductions were negligible, which still makes the modified GNPs significant as an effective additive for the natural rubber in applications requiring high abrasion resistance.

Green synthesis of a photocatalyst Ag/TiO2 nanocomposite using Cleistocalyx operculatus leaf extract for degradation of organic dyes.

Green synthesis has emerged as a sustainable approach for the fabrication of nanomaterials in the last few decades. Leaf extracts have been considered low-cost and highly efficient reactants for the synthesis of nanoparticles. In this study, an aqueous extract of Cleistocalyx operculatus leaves was employed as a reductant to synthesize Ag/TiO2 nanocomposites. The morphology, structure, and interface interaction of the Ag/TiO2 nanocomposites were investigated by (i) X-ray diffraction (XRD) to determine the crystallinity, (ii) scanning electron microscopy (SEM) to determine the morphologies, (iii) energy dispersive X-ray spectroscopy (EDX) to determine the elemental composition and distribution, and (iv) diffuse reflectance spectroscopy (DRS) to understand the optical properties. The results showed that Ag nanoparticles (AgNPs) with particle sizes of 20-40 nm homogeneously covered the surface of the TiO2 nanoparticles. The green-synthesized Ag/TiO2 nanocomposite also exhibited an excellent photodegradation ability for Rhodamine B with a removal percentage up to 91.4% after 180 min of photocatalytic reaction.

Ultrasonic-Assisted Synthesis of Fe-BTC-PEG Metal-Organic Complex: An Effective and Safety Nanocarrier for Anticancer Drug Delivery.

The porous metal-organic complexes are emerging as novel carriers for effective and safe delivery of drugs for cancer treatment, minimizing the side effect of drug overuse during cancer treatment. This study fabricated the Fe-BTC-PEG metal-organic complex from Fe ions, trimesic acid, and poly(ethylene glycol) as precursors using an ultrasonic-assisted method. The morphology and crystallinity of the resultant complex were observed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. FTIR spectroscopy was employed to investigate the functional groups on the surface of the Fe-BTC-PEG complex. The result showed that the prepared Fe-BTC-PEG complex was in particle form with low crystallinity and diameter ranging from 100 to 200 nm. The obtained Fe-BTC-PEG complex exhibited a high loading capacity for the 5-fluorouracil (5-FU) anticancer drug with a maximal capacity of 364 mg/g. The releasing behavior of 5-fluorouracil from the 5-FU-loaded Fe-BTC-PEG complex was studied. Notably, the acute oral toxicity of the Fe-BTC-PEG metal-organic complex was also carried out to evaluate the safety of the material in practical application.

Self-Assembly of Porphyrin Nanofibers on ZnO Nanoparticles for the Enhanced Photocatalytic Performance for Organic Dye Degradation.

Synthesizing novel photocatalysts that can effectively harvest photon energy over a wide range of the solar spectrum for practical applications is vital. Porphyrin-derived nanostructures with properties similar to those of chlorophyll have emerged as promising candidates to meet this requirement. In this study, tetrakis(4-carboxyphenyl) porphyrin (TCPP) nanofibers were formed on the surface of ZnO nanoparticles using a simple self-assembly approach. The obtained ZnO/TCPP nanofiber composites were characterized via scanning electron microscopy, X-ray diffraction analysis, and ultraviolet-visible absorbance and reflectance measurements. The results demonstrated that the ZnO nanoparticles with an average size of approximately 37 nm were well integrated in the TCPP nanofiber matrix. The resultant composite showed photocatalytic activity of ZnO and TCPP nanofibers concomitantly, with band gap energies of 3.12 and 2.43 eV, respectively. The ZnO/TCPP photocatalyst exhibited remarkable photocatalytic performance for RhB degradation with a removal percentage of 97% after 180 min of irradiation under simulated sunlight because of the synergetic activity of ZnO and TCPP nanofibers. The dominant active species participating in the photocatalytic reaction were •O2 - and OH•, resulting in enhanced charge separation by exciton-coupled charge-transfer processes between the hybrid materials.

New TiO2-doped Cu-Mg spinel-ferrite-based photocatalyst for degrading highly toxic rhodamine B dye in wastewater.

The quest for finding an effective photocatalyst for environmental remediation and treatment strategies is attracting considerable attentions from scientists. In this study, a new hybrid material, Cu0.5Mg0.5Fe2O4-TiO2, was designed and fabricated using coprecipitation and sol-gel approaches for degrading organic dyes in wastewater. The prepared hybrid materials were fully characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results revealed that the Cu0.5Mg0.5Fe2O4-TiO2 hybrid material was successfully synthesized with average particle sizes of 40.09 nm for TiO2 and 27.9 nm for Cu0.5Mg0.5Fe2O4. As the calculated bandgap energy of the hybrid material was approximately 2.86 eV, it could harvest photon energy in the visible region. Results indicate that the Cu0.5Mg0.5Fe2O4-TiO2 also had reasonable magnetic properties with a saturation magnetization value of 11.2 emu/g, which is a level of making easy separation from the solution by an external magnet. The resultant Cu0.5Mg0.5Fe2O4-TiO2 hybrid material revealed better photocatalytic performance for rhodamine B dye (consistent removal rate in the 13.96 × 10-3 min-1) compared with free-standing Cu0.5Mg0.5Fe2O4 and TiO2 materials. The recyclability and photocatalytic mechanism of Cu0.5Mg0.5Fe2O4-TiO2 are also well discussed.

Scalable Fabrication of Modified Graphene Nanoplatelets as an Effective Additive for Engine Lubricant Oil.

The use of nano-additives is widely recognized as a cheap and effective pathway to improve the performance of lubrication by minimizing the energy loss from friction and wear, especially in diesel engines. In this work, a simple and scalable protocol was proposed to fabricate a graphene additive to improve the engine lubricant oil. Graphene nanoplates (GNPs) were obtained by a one-step chemical exfoliation of natural graphite and were successfully modified with a surfactant and an organic compound to obtain a modified GNP additive, that can be facilely dispersed in lubricant oil. The GNPs and modified GNP additive were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The prepared GNPs had wrinkled and crumpled structures with a diameter of 10-30 µm and a thickness of less than 15 nm. After modification, the GNP surfaces were uniformly covered with the organic compound. The addition of the modified GNP additive to the engine lubricant oil significantly enhanced the friction and antiwear performance. The highest reduction of 35% was determined for the wear scar diameter with a GNP additive concentration of approximately 0.05%. The mechanism for lubrication enhancement by graphene additives was also briefly discussed.

Effective Removal of Pb(II) from Aqueous Media by a New Design of Cu-Mg Binary Ferrite.

Metal oxides and their composites have been extensively studied as effective adsorbents for the removal of heavy metals from aqueous solutions in environmental remediation. In this work, Cu0.5Mg0.5Fe2O4 was synthesized by a co-precipitation method followed by calcination (900 °C) and investigated for Pb(II) adsorption. The resultant samples were characterized by various analytical techniques including X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The results revealed that single-phase cubic spinel was obtained by the calcination of as-synthesized samples at a temperature of 900 °C. Cu0.5Mg0.5Fe2O4 ferrite is a mesoporous material with a surface area, a total pore volume, and an average pore size of 41.3 m2/g, 0.2 cm3/g, and 15.1 nm, respectively. Pb(II) adsorption on Cu0.5Mg0.5Fe2O4 fitted well to the Langmuir model, indicating monolayer adsorption with a maximum capacity of 57.7 mg/g. The pseudo-second-order kinetic model can exactly describe Pb(II) adsorption with the normalized standard deviation (Δq) of 1.24%. The obtained results confirmed that the Cu0.5Mg0.5Fe2O4 ternary oxides exhibit a high adsorption capacity toward Pb(II), thanks to the increase in active adsorptive sites of ferrite.

Combined biochar vertical flow and free-water surface constructed wetland system for dormitory sewage treatment and reuse.

A two-stage treatment system that included vertical flow (VF) and free-water surface (FWS) constructed wetlands was investigated for the dual purposes of sewage treatment and reuse. The VF included four layers (biochar, sand, gravel, and sandy soil), and the FWS was installed after the VF and used as a polishing tank. Two types of local plants, namely Colocasia esculenta and Canna indica, were planted in the VF and FWS, respectively. The system operated for approximately six months, and the experimental period was categorized into four stages that corresponded to changes in the hydraulic loading rate (HLR) (0.02-0.12 m/d). The removal efficiencies for total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD5), ammonia (NH4-N), and total coliform (Tcol) were 71 ± 11%, 73 ± 13%, 79 ± 11%, 91 ± 3%, and 70 ± 20%, respectively. At HLRs of 0.04-0.06 m/d, the COD and BOD5 levels satisfied Vietnam's irrigation standards, with removable rates of 64% and 88%, respectively, and the TSS and Tcol levels satisfied Vietnam's standards for potable water. Furthermore, the NO3-N levels satisfied the reuse limits, whereas the NH4-N levels exceeded the reuse standards. At high HLRs (e.g., 0.12 m/d), all the effluent parameters, except Tcol and NO3-N, exceeded the standards.

Self-assembled kanamycin antibiotic-inorganic microflowers and their application as a photocatalyst for the removal of organic dyes.

Construction of hybrid three-dimensional (3D) hierarchical nanostructures via self-assembly of organic and inorganic compounds have recently attracted immense interest from scientists due to their unique properties and promise in a large range of applications. In this article, hybrid flower structures were successfully constructed by self-assembly an antibiotic, kanamycin, with Cu2+. The flower-like morphology was observed by scanning electron microscopy, to be approximately 4 µm in diameter and about 10 nm in thickness. FTIR spectroscopy and X-ray diffraction confirmed the antibiotic-inorganic hybrid structure was uniform composition, and showed crystallinity due to ordered self-assembly. The hybrid flowers showed high photocatalytic activity towards degradation of methyl blue during 240 minutes under visible light irradiation. A possible mechanism of photocatalytic activity was also proposed, that exposes the inherent advantages in using antibiotic-inorganic hybrid flowers as photocatalysts, where self-assembly can be used to generate active, high surface area structures for photodegradation of pollutants.

Supramolecular super-helix formation via self-assembly of naphthalene diimide functionalised with bile acid derivatives.

The design of chiral chromophores that lead to self-assembly of higher order helical structures is a powerful tool to understand the hierarchical helical structures of molecules of nature. In this work, we present a self-assembled helical super-structure produced via facial stacking of a bile acid bolaamphiphile derivative with a naphthalene diimide core (NDI-DCA), driven by solvophobic effects in THF-H2O solvent mixtures. The chirality of the helical microstructure is directed by the multiple chiral centres in the precursor molecule. The chirality of the hierarchical assemblies was observed using circular dichroism (CD), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. We propose that the NDI-DCA super-structures are formed via similar interactions and mechanisms to those observed in biological molecules such as proteins and DNA.

Supramolecular Chiral Helical Ribbons of Tetraphenylethylene-Appended Naphthalenediimide Controlled by Solvent and Induced by l- and d-Alanine Spacers.

Naphthalenediimide-tetraphenylethylene conjugates with an alanine spacer (coded as: NDI-(Ala-TPE)2 ) were synthesized to study the influence of the chirality of the amino acid spacer on its self-assemblies. Here we particularly show that NDI-Ala-TPE bearing l-alanine gives left-handed (M-type) helical superstructure, while d-alanine produces right-handed (P-type) helical ribbons in THF:H2 O at 40:60 % v/v ratio. However, particular aggregates were observed at 20:80 % v/v ratio. Circular dichroism was used to characterise the induction of chirality and the handedness of the helical superstructures, and the microstructure of the self-assembled materials was visualised using scanning electron microscopy while DLS analysis confirmed the formation of particular aggregates in solution.

Chiral Supramolecular Assemblies from an Achiral Naphthalene Diimide Bearing a Urea Moiety.

The ordering of organic molecules in a supramolecular self-assembly determines their physical, chemical, and photonic properties. Here, we report the aggregation of two achiral naphthalene diimides (NDIs), in which phenyl moieties are linked to the NDI core via a urea subunit, leading to chiral supramolecular assemblies in THF/methylcyclohexane. Circular dichroism spectroscopic analysis of twisted ribbons deposited from solutions indicated a mixture of left- and right-handed nanostructures for one NDI, whereas only left-handed structures were observed for the other one. Furthermore, this study also shows the effect of large atoms such as iodine on the self-assembly process, which governs and controls the helicity of the produced microstructures. The supramolecular assemblies were characterized by UV/Vis, fluorescence emission, CD, SEM, and XRD techniques.

Dynamic multistimuli-responsive reversible chiral transformation in supramolecular helices.

The design of new chiral chromophores that allow tunable assembly of higher order helical structures by using natural stimuli offers promising avenue in understanding various biological processes. In particular, access to dynamic multistimuli-responsive systems can provide real-time monitoring of chiral transformation in chemical and biological systems. We report on the synthesis of naphthalenediimide appended L-glutamate (NDI-L-Glu) that self-assembles into chiral supramolecular structures under physiological conditions. Specifically, NDI-L-Glu shows a mixture of left- and right-handed helices under physiological conditions, and any deviation from the ambient biochemical environment has a remarkable influence on the chirality of these structures. For instance, acidic environments shift the helicity to left-handedness while the alkaline conditions reversed the helical structures to right-handedness, thereby mimicking the molecular virulence mechanism of tobacco mosaic virus (TMV). The chirality of these supramolecular assemblies can also be controllably tuned by using temperature as an external stimulus, allowing reversible flip of helicity.