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Pesticides can have harmful impacts on the environment and living organisms. Thus, removing them from polluted water is crucial. In this study, a bionanocomposite of carboxymethyl tragacanth-grafted-poly(3-aminophenol)/zinc oxide@iron oxide (CMT-g-P3AP/ZnO@Fe3O4) synthesized by in situ copolymerization as an efficient adsorbent to eliminate the acetamiprid pesticide from polluted water. The CMT-g-P3AP/ZnO@Fe3O4 magnetic nanocomposite was analyzed utilizing various techniques including FTIR, EDX, FESEM, XRD, BET, CHNSO, and TGA. The results displayed that the resulting nanocomposite with maximum adsorption capacity (Qmax) successfully removed the acetamiprid pesticide from polluted water under optimal conditions such as pH of 7.00, 5.00 mg of adsorbent, 20.0 min duration, and 400 mg/L acetamiprid concentration. According to the linear Langmuir isotherm, the Qmax of the biosorbent was 833 mg/g. The experimental adsorption data fitted well with Temkin's nonlinear isotherm model. The adsorption kinetic data were closely related to the Weber-Morris intraparticle diffusion nonlinear model. After three repetitive cycles, CMT-g-P3AP/ZnO@Fe3O4 can be outstandingly renewed and recycled without significant reduction in its adsorption efficacy, as evidenced by the adsorption-desorption experiments. In addition, the CMT-g-P3AP/ZnO@Fe3O4 displayed the good antibacterial activity against E. coli and S. aureus.
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Antibacterianos , Neonicotinoides , Poluentes Químicos da Água , Óxido de Zinco , Poluentes Químicos da Água/química , Óxido de Zinco/química , Adsorção , Antibacterianos/química , Neonicotinoides/química , Tragacanto/química , Nanocompostos/química , Purificação da Água/métodos , Praguicidas/químicaRESUMO
In recent years, MXene has become one of the most intriguing two-dimensional layered (2Dl) materials extensively explored for various applications. In this study, a Ti3C2 MXene/rGo-Cu2O Nanocomposite (TGCNCs) was developed to eliminate Safranin-O effectively (SO) and Acid Fuchsin (AF) as cationic dyes from the aquatic environment. Multistep was involved in the preparation of the adsorbent system, including the Preparation of Ti3C2, after that, GO synthesis by the Humer method, followed by rGO production, then added CuSO4 to obtain a final Nanocomposite (NCs) called "TGCNCs". The structure of TGCNCs can be varied in several ways, including FTIR, SEM, TGA, Zeta, EDX, XRD, and BET, to affirm the efficacious preparation of TGCNCs. A novel adsorbent system was developed to remove SO and AF, both cationic dyes. Various adsorption conditions have been optimized through batch adsorption tests, including the pH of the solution (4-12), the effect of dosage (0.003-0.03 g), the impact of the contact time (5-30 min), and the effect of beginning dye concentration (25-250 mg/L). Accordingly, the TGCNCs exhibited excellent fitting for Freundlich isotherm mode, resulting in maximum AF and SO adsorption capacities of 909.09 and 769.23 mg g-1. This research on adsorption kinetics suggests that a pseudo-second-order (PSO) model would fit well with the experimental data (RSO2 = 0.998 and RAF2 = 0.990). It is evident from the thermodynamic parameters that adsorption is an endothermic process that is spontaneous and favorable. During the adsorption of SO and AF onto NCs, it is hypothesized that these molecules interact intramolecularly through stacking interactions, H-bond interactions, electrostatic interactions, and entrapment within the polymeric Poros structure nanocomposite. Regeneration studies lasting up to five cycles were the most effective for both organic dyes under study.
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Cobre , Nanocompostos , Fenazinas , Termodinâmica , Titânio , Poluentes Químicos da Água , Nanocompostos/química , Fenazinas/química , Cinética , Adsorção , Titânio/química , Poluentes Químicos da Água/química , Cobre/química , Corantes/química , Corantes de Rosanilina/química , Grafite/química , BenzenossulfonatosRESUMO
Staphylococcus aureus is a unique challenge for the healthcare system because it can form biofilms, is resistant to the host's immune system, and is resistant to numerous antimicrobial therapies. The aim of this study was to investigate the effect of poly (lactic-co-glycolic acid) (PLGA) polymer nanoparticles loaded with vancomycin and conjugated with lysostaphin (PLGA-VAN-LYS) on inhibiting S. aureus biofilm formation. Nano drug carriers were produced using the double emulsion evaporation process. we examined the physicochemical characteristics of the nanoparticles, including particle size, polydispersity index (PDI), zeta potential, drug loading (DL), entrapment efficiency (EE), Lysostaphin conjugation efficiency (LCE), and shape. The effect of the nano drug carriers on S. aureus strains was evaluated by determining the minimum inhibitory concentration (MIC), conducting biofilm formation inhibition studies, and performing agar well diffusion tests. The average size, PDI, zeta potential, DL, EE, and LCE of PLGA-VAN-LYS were 320.5 ± 35 nm, 0.270 ± 0.012, -19.5 ± 1.3 mV, 16.75 ± 2.5%, 94.62 ± 2.6%, and 37% respectively. Both the agar well diffusion and MIC tests did not show a distinction between vancomycin and the nano drug carriers after 72 h. However, the results of the biofilm analysis demonstrated that the nano drug carrier had a stronger inhibitory effect on biofilm formation compared to the free drug. The use of this technology for treating hospital infections caused by the Staphylococcus bacteria may have favorable effects on staphylococcal infections, considering the efficacy of the nano medicine carrier developed in this study.
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Infecções Estafilocócicas , Vancomicina , Humanos , Vancomicina/farmacologia , Glicóis , Staphylococcus aureus , Ágar , Lisostafina , Polímeros , BiofilmesRESUMO
In this work, a new dendrimer modified magnetic graphene oxide (GO) was used as a substrate for electrodeposition of Au nanoparticles. The modified magnetic electrode was employed for sensitive measuring of As(III) ion as a well-established human carcinogen. The prepared electrochemical device exhibits excellent activity towards As(III) detection using the square wave anodic stripping voltammetry (SWASV) protocol. At optimum conditions (deposition potential at -0.5 V for 100 s in 0.1 M acetate buffer with pH 5.0), a linear range from 1.0 to 125.0 µgL-1 with a low detection limit (calculated by S/N = 3) of 0.47 µg L-1 was obtained. In addition to the simplicity and sensitivity of the proposed sensor, its high selectivity against some major interfering agents, such as Cu(II) and Hg(II) makes it an appreciable sensing tool for the screening of As(III). In addition, the sensor revealed satisfactory results for detection of As(III) in different water samples, and the accuracy of obtained data were confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) setup. Accounting for the high sensitivity, remarkable selectivity and good reproducibility, the established electrochemical strategy has great potential for analysis of As(III) in environmental matrices.
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Ouro , Nanopartículas Metálicas , Humanos , Ouro/química , Reprodutibilidade dos Testes , Nanopartículas Metálicas/química , Fenômenos MagnéticosRESUMO
The release of pharmaceuticals into the environment induces adverse effects on the metabolism of humans and other living species, calling for advanced remediation methods. Conventional removal methods are often non-selective and cause secondary contamination. These issues may be partly solved by the use of recently-developped adsorbents such as molecularly imprinted polymers. Here we review the synthesis and application of molecularly imprinted polymers for removing pharmaceuticals in water. Molecularly imprinted polymers are synthesized via several multiple-step polymerization methods. Molecularly imprinted polymers are potent adsorbents at the laboratory scale, yet their efficiency is limited by template leakage and polymer quality. Adsorption performance of multi-templated molecularly imprinted polymers depends on the design of wastewater treatment plants, pharmaceutical consumption patterns and the population serviced by these wastewater treatment plants.
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Metal-based nanoentities, apart from being indispensable research tools, have found extensive use in the industrial and biomedical arena. Because their biological impacts are governed by factors such as size, shape, and composition, such issues must be taken into account when these materials are incorporated into multi-component ensembles for clinical applications. The size and shape (rods, wires, sheets, tubes, and cages) of metallic nanostructures influence cell viability by virtue of their varied geometry and physicochemical interactions with mammalian cell membranes. The anisotropic properties of nonspherical metal-based nanoarchitectures render them exciting candidates for biomedical applications. Here, the size-, shape-, and composition-dependent properties of nonspherical metal-based nanoarchitectures are reviewed in the context of their potential applications in cancer diagnostics and therapeutics, as well as, in regenerative medicine. Strategies for the synthesis of nonspherical metal-based nanoarchitectures and their cytotoxicity and immunological profiles are also comprehensively appraised.
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Nanopartículas Metálicas , Nanoestruturas , Anisotropia , Sobrevivência Celular , MetaisRESUMO
Microneedle (MN) patches consisting of miniature needles have emerged as a promising tool to perforate the stratum corneum and translocate biomolecules into the dermis in a minimally invasive manner. Stimuli-responsive MN patches represent emerging drug delivery systems that release cargos on-demand as a response to internal or external triggers. In this review, a variety of stimuli-responsive MN patches for controlled drug release are introduced, covering the mechanisms of action toward different indications. Future opportunities and challenges with respect to clinical translation are also discussed.
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In this study, nanocomposite hydrogels composed of sodium carboxymethylated starch (CMS)-containing CuO nanoparticles (CMS@CuO) were synthesized and used as experimental wound healing materials. The hydrogels were fabricated by a solution-casting technique using citric acid as a crosslinking agent. They were characterized by Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) to evaluate their physicochemical properties. In addition, swelling, antibacterial activities, antioxidant activities, cytotoxicity, and in vivo wound healing were investigated to evaluate the wound healing potential of the CMS@CuO nanocomposite hydrogels. Growth inhibition of the Gram-positive and Gram-negative pathogens, antioxidant activity, and swelling were observed in the CMS@CuO nanocomposite hydrogels containing 2 wt.% and 4 wt.% CuO nanoparticles. The hydrogel containing 2 wt.% CuO nanoparticles displayed low toxicity to human fibroblasts and exhibited good biocompatibility. Wounds created in rats and treated with the CMS@2%CuO nanocomposite hydrogel healed within 13 days, whereas wounds were still present when treated for the same time-period with CMS only. The impact of antibacterial and antioxidant activities on accelerating wound healing could be ascribed to the antibacterial and antioxidant activities of the nanocomposite hydrogel. Incorporation of CuO nanoparticles in the hydrogel improved its antibacterial properties, antioxidant activity, and degree of swelling. The present nanocomposite hydrogel has the potential to be used clinically as a novel wound healing material.
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Antibacterianos/química , Antioxidantes/química , Cobre/química , Hidrogéis/química , Nanopartículas/química , Amido/análogos & derivados , Cicatrização/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Células Cultivadas , Quitosana/química , Fibroblastos/efeitos dos fármacos , Humanos , Masculino , Testes de Sensibilidade Microbiana , Nanocompostos/química , Ratos , Ratos Wistar , Amido/química , Difração de Raios XRESUMO
The self-assembled natural and synthetic polymers are booming. However, natural polymers obtained from native or modified carbohydrate polymers (CPs), such as celluloses, chitosan, glucans, gums, pectins, and starches, have had special attention as raw material in the manufacture of self-assembled polymer composite materials having several forms: films, hydrogels, micelles, and particles. The easy manipulation of the architecture of the CPs, as well as their high availability in nature, low cost, and being sustainable and green polymers have been the main positive points in the use of them for different applications. CPs have been used as building blocks for composite structures, and their easy orientation and ordering has given rise to self-assembled CPs (SCPs). These macromolecules have been little studied for food applications. Nonetheless, their research has grown mainly in the last 5 years as encapsulated food additive wall materials, food coatings, and edible films. The multifaceted properties (systems sensitive to pH, temperature, ionic strength, types of ions, mechanical force, and enzymes) of these devices are leading to the development of advanced food materials. This review article focused on the analysis of SCPs for food applications in order to encourage other research groups for their preparation and implementation.
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Water contamination by toxic heavy metal ions and dyes remains a serious public health problem for humans, so attention on specific methods and technologies to remove heavy metal ions and dyes from wastewaters/aqueous solutions are desired. Numerous adsorbents have been reported for the removal of heavy metal ions/dyes from wastewaters/aqueous solutions. Polyaniline (PANI) and its derivatives, as conducting polymers, are good adsorbents to remove various kinds of heavy metal ions and dyes from wastewaters/aqueous solutions. The nanoadsorbents based on PANI and its derivatives have received much consideration, and are extensively reported in literature. This review focuses on the PANI and its derivatives based on nanoadsorbents for water purification. Various types of these nanoadsorbents used for the removal of heavy metal ions/dyes from wastewaters/aqueous solutions are also briefly compared in this review.
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Metais Pesados , Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Adsorção , Compostos de Anilina , Corantes , Humanos , Íons , PolímerosRESUMO
This study evaluated the effectiveness of using nanocomposite (NCs) of xanthan gum grafted polyacrylamide crosslinked Borax - iron oxide nanoparticle (XG-g-pAAm-CL-Borax-IONP) to remove the amoxicillin antibiotic (AMX) from an aquatic environment. To confirm the structural characteristics of the prepared XG-g-pAAm-CL-Borax-IONP NCs, unique characterization methods (XRD, FT-IR, FE-SEM, EDX, BET, TGA, Zeta, and VSM) were used. Adsorption experimental setups were performed with the influence of solution pH (4-9), the effect of adsorbent dose (0.003-0.02 g), the effect of contact time (5-45 min), and the effect of initial AMX concentration (50-400 mg/L) to achieve the most efficient adsorption conditions. Based on the Freundlich isotherm model, XG-g-pAAm-CL-Borax-IONP NCs provided the maximum AMX adsorption capacity of 1183.639 mg/g. This research on adsorption kinetics also established that the pseudo-second-order model (R2 = 0.991) is outstanding compatibility with the experimental results. AMX adsorption on the NCs may occur through intermolecular hydrogen bonding, diffusion, and trapping into the polymer network. Even after five cycles, these NCs still displayed the best performance. Based on these results, XG-g-pAAm-CL-Borax-IONP NCs may be a viable material for the purification of AMX from contaminated water.
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Resinas Acrílicas , Amoxicilina , Boratos , Nanocompostos , Polissacarídeos Bacterianos , Poluentes Químicos da Água , Nanocompostos/química , Poluentes Químicos da Água/química , Resinas Acrílicas/química , Amoxicilina/química , Polissacarídeos Bacterianos/química , Adsorção , Boratos/química , Cinética , Antibacterianos/química , Purificação da Água/métodos , Concentração de Íons de HidrogênioRESUMO
The elimination of pesticides from polluted water is critical due to their harmful environmental and biological impacts. Recently, there has been interest in utilizing natural polymer-based adsorbents as an eco-friendly approach to eliminate or reduce the levels of water pollutants. In this work, we synthesized an antimicrobial and magnetic bionanocomposite consisting of carboxymethyl gond katira-grafted- poly(3-aminobenzoic acid) with iron oxide and zinc oxide NPs (CMT-g-P3ABA/ZnO/Fe3O4) through an in situ polymerization reaction and examined for its ability to adsorb the pesticide acetamiprid (AP). The bionanocomposite was characterized using several analytical techniques, including spectroscopy; XRD presented the crystalline structure of ZnO/Fe3O4 in the CMT-g-P3ABA amorphous matrix. The ZnO/Fe3O4 partially aggregated formation and exhibited polyhedral crystal shapes was depicted by electron microscopy images, vibrating sample magnetometer (45.06 emu/g), porosimetry (5.52 m2/g), and thermal (Chair yield of approximately 43.83 %) and elemental analyses. Under various conditions, including solution pH (4-9), adsorbent dosage (0.005-0.025 g), time of contact (10-30 min), and pesticide preliminary concentration (200-400 mg/L) in 10 mL of the solution. Based on this research, Adsorption data were perfectly fitted by the Freundlich isotherm model with RAP2= 0.99038, while the pseudo-second-order (PSO) model well-explained adsorption kinetics with RAP2= 0.99847. AP adsorption to the CMT-g-P3ABA/ZnO/Fe3O4 bionanocomposite was successful due to hydrophobic interactions, hydrogen bonding, and π-π stacking. Furthermore, adsorption-desorption experiments demonstrated that the bionanocomposite could be regenerated after three reuse cycles without considerable loss of pesticide removal performance. The bionanocomposite also exhibited promising antimicrobial activity in contradiction to test bacteria.
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Antibacterianos , Neonicotinoides , Poluentes Químicos da Água , Purificação da Água , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Purificação da Água/métodos , Antibacterianos/química , Antibacterianos/farmacologia , Neonicotinoides/química , Cinética , Nanocompostos/química , Óxido de Zinco/químicaRESUMO
Despite the advantages of topical administration in the treatment of skin diseases, current marketed preparations face the challenge of the skin's barrier effect, leading to low therapeutic effectiveness and undesirable side effects. Hence, in recent years the management of skin wounds, the main morbidity-causing complication in hospital environments, and atopic dermatitis, the most common inflammatory skin disease, has become a great concern. Fortunately, new, more effective, and safer treatments are already under development, with chitosan, starch, silk fibroin, agarose, hyaluronic acid, alginate, collagen, and gelatin having been used for the development of nanoparticles, liposomes, niosomes and/or hydrogels to improve the delivery of several molecules for the treatment of these diseases. Biocompatibility, biodegradability, increased viscosity, controlled drug delivery, increased drug retention in the epidermis, and overall mitigation of adverse effects, contribute to an effective treatment, additionally providing intrinsic antimicrobial and wound healing properties. In this review, some of the most recent success cases of biopolymer-based drug delivery systems as part of nanocarriers, semi-solid hydrogel matrices, or both (hybrid systems), for the management of skin wounds and atopic dermatitis, are critically discussed, including composition and in vitro, ex vivo and in vivo characterization, showing the promise of these external drug delivery systems.
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Dermatite Atópica , Humanos , Dermatite Atópica/tratamento farmacológico , Cicatrização , Sistemas de Liberação de Medicamentos , Biopolímeros/farmacologia , Colágeno/farmacologia , Hidrogéis/farmacologia , Lipossomos/farmacologiaRESUMO
Injectable hydrogels based on biopolymers, fabricated utilizing diverse chemical and physical methodologies, exhibit exceptional physical, chemical, and biological properties. They have multifaceted applications encompassing wound healing, tissue regeneration, and across diverse scientific realms. This review critically evaluates their largely uncharted potential in ophthalmology, elucidating their diverse applications across an array of ocular diseases. These conditions include glaucoma, cataracts, corneal disorders (spanning from age-related degeneration to trauma, infections, and underlying chronic illnesses), retina-associated ailments (such as diabetic retinopathy, retinitis pigmentosa, and age-related macular degeneration (AMD)), eyelid abnormalities, and uveal melanoma (UM). This study provides a thorough analysis of applications of injectable hydrogels based on biopolymers across these ocular disorders. Injectable hydrogels based on biopolymers can be customized to have specific physical, chemical, and biological properties that make them suitable as drug delivery vehicles, tissue scaffolds, and sealants in the eye. For example, they can be engineered to have optimum viscosity to be injected intravitreally and sustain drug release to treat retinal diseases. Their porous structure and biocompatibility promote cellular infiltration to regenerate diseased corneal tissue. By accentuating their indispensable role in ocular disease treatment, this review strives to present innovative and targeted approaches in this domain, thereby advancing ocular therapeutics.
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Oftalmopatias , Hidrogéis , Hidrogéis/química , Humanos , Biopolímeros/química , Oftalmopatias/tratamento farmacológico , Animais , Sistemas de Liberação de Medicamentos , Injeções , Materiais Biocompatíveis/químicaRESUMO
Cancer, a global health challenge of utmost severity, necessitates innovative approaches beyond conventional treatments (e.g., surgery, chemotherapy, and radiation therapy). Unfortunately, these approaches frequently fail to achieve comprehensive cancer control, characterized by inefficacy, non-specific drug distribution, and the emergence of adverse side effects. Nanoscale systems based on natural polymers like chitosan have garnered significant attention as promising platforms for cancer diagnosis and therapy owing to chitosan's inherent biocompatibility, biodegradability, nontoxicity, and ease of functionalization. Herein, recent advancements pertaining to the applications of chitosan nanoparticles in cancer imaging and drug/gene delivery are deliberated. The readers are introduced to conventional non-stimuli-responsive and stimuli-responsive chitosan-based nanoplatforms. External triggers like light, heat, and ultrasound and internal stimuli such as pH and redox gradients are highlighted. The utilization of chitosan nanomaterials as contrast agents or scaffolds for multimodal imaging techniques e.g., magnetic resonance, fluorescence, and nuclear imaging is represented. Key applications in targeted chemotherapy, combination therapy, photothermal therapy, and nucleic acid delivery using chitosan nanoformulations are explored for cancer treatment. The immunomodulatory effects of chitosan and its role in impacting the tumor microenvironment are analyzed. Finally, challenges, prospects, and future outlooks regarding the use of chitosan-based nanosystems are discussed.
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Quitosana , Nanopartículas , Nanoestruturas , Neoplasias , Humanos , Quitosana/química , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Nanoestruturas/química , Nanopartículas/uso terapêutico , Nanopartículas/química , Microambiente TumoralRESUMO
Intervertebral disc degeneration (IVDD) is a chronic degenerative disease involving the aging and loss of proliferative capacity of nucleus pulposus cells (NPCs), processes heavily dependent on mitochondrial dynamics and autophagic flux. This study finds that the absence of BCL2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) is associated with senescence-related NPC degeneration, disrupting mitochondrial quality control. Bone marrow mesenchymal stem cells (BMSCs) have multidirectional differentiation potential and produce extracellular vesicles containing cellular activators. Therefore, in this study, BMSCs are induced under hypoxic stimulation to deliver BNIP3-rich extracellular vesicles to NPCs, thereby alleviating aging-associated mitochondrial autophagic flux, promoting damaged mitochondrial clearance, and restoring mitochondrial quality control. Mechanistically, BNIP3 is shown to interact with the membrane-bound protein annexin A2 (ANXA2), enabling the liberation of the transcription factor EB (TFEB) from the ANXA2-TFEB complex, promoting TFEB nuclear translocation, and regulating autophagy and lysosomal gene activation. Furthermore, a rat model of IVDD is established and verified the in vivo efficacy of the exosomes in repairing disc injuries, delaying NPC aging, and promoting extracellular matrix (ECM) synthesis. In summary, hypoxia-induced BMSC exosomes deliver BNIP3-rich vesicles to alleviate disc degeneration by activating the mitochondrial BNIP3/ANXA2/TFEB axis, providing a new target for IVDD treatment.
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Broad-spectrum antibiotics from the fluoroquinolone family have emerged as prominent water contaminants, among other pharmaceutical pollutants. In the present study, an antibacterial magnetic molecularly imprinted polymer (MMIP) composite was successfully fabricated using carboxy methyl dextrin grafted to poly(aniline-co-meta-phenylenediamine) in the presence of Fe3O4/CuO nanoparticles and ciprofloxacin antibiotic. The characteristics of obtained materials were investigated using FTIR, XRD, VSM, TGA, EDX, FE-SEM, zeta potential, and BETanalyses. Afterward, the MMIP's antibacterial activity and adsorption effectiveness for removing ciprofloxacin from aqueous solutions were explored. The results of the antibacterial tests showed that MMIP had an antibacterial effect against Escherichia coli, a Gram-negative pathogen (16 mm), and Staphylococcus aureus, a Gram-positive pathogen (22 mm). Adsorption efficacy was evaluated under a variety of experimental conditions, including solution pH, adsorbent dosage, contact time, and initial concentration. The maximum adsorption capacity (Qmax) of the MMIP for ciprofloxacin was determined to be 1111.1 mg/g using 3 mg of MMIP, with an initial concentration of 400 mg/L of ciprofloxacin at pH 7, within 15 min, and agitated at 25 °C, and the experimental adsorption results were well-described by the Freundlich isotherm model. The adsorption kinetic data were well represented by the pseudo-second-order model. Electrostatic interaction, cation exchange, π-π interactions, and hydrogen bonding were mostly able to adsorb the majority of the ciprofloxacin onto the MMIP. Adsorption-desorption experiments revealed that the MMIP could be retrieved and reused with no noticeable reduction in adsorption efficacy after three consecutive cycles.
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The electrochemical behavior of the immobilized tyrosinase (Tyrase) on a modified glassy carbon electrode with carboxymethyl starch-graft-polyaniline/multi-walled carbon nanotubes nanocomposite (CMS-g-PANI@MWCNTs) was investigated. The molecular properties of CMS-g-PANI@MWCNTs nanocomposite and its morphological characterization were examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM). A simple drop-casting method was employed to immobilize Tyrase on the CMS-g-PANI@MWCNTs nanocomposite. In the cyclic voltammogram (CV), a pair of redox peaks were observed at the potentials of +0.25 to -0.1 V and E°' was equal to 0.1 V and the apparent rate constant of electron transfer (Ks) was calculated at 0.4 s-1. Using differential pulse voltammetry (DPV), the sensitivity and selectivity of the biosensor were investigated. The biosensor exhibits linearity towards catechol and L-dopa in the concentration range of 5-100 and 10-300 µM with a sensitivity of 2.4 and 1.11 µA µΜ-1 cm-2 and limit of detection (LOD) 25 and 30 µM, respectively. The Michaelis-Menten constant (Km) was calculated at 42 µΜ for catechol and 86 µΜ for L-dopa. After 28 working days, the biosensor provided good repeatability and selectivity, and maintained 67% of its stability. The existence of -COO- and -OH groups in carboxymethyl starch, -NH2 groups in polyaniline, and high surface-to-volume ratio and electrical conductivity of multi-walled carbon nanotubes in the CMS-g-PANI@MWCNTs nanocomposite cause good Tyrase immobilization on the surface of the electrode.
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Técnicas Biossensoriais , Nanocompostos , Nanotubos de Carbono , Monofenol Mono-Oxigenase , Nanotubos de Carbono/química , Levodopa , Nanocompostos/química , Técnicas Biossensoriais/métodos , EletrodosRESUMO
The lead is a heavy metal with hazardous impacts on environment and human life. Lead-free perovskite solar cells have attracted much attention in recent years, due to eco-friendly characteristics. Meanwhile, Pb-containing cells showed the highest efficiencies among the various types of cells. Hence, designing novel Pb-free solar cells with comparable or better performance than the Pb-containing ones is highly required. In this work, a lead-free methyl-ammonium-germanium-iodide (MAGeI3)-based perovskite solar cell with ITO/TiO2/MAGeI3/Spiro-OMeTAD/Ag multilayer nanostructure has been proposed and its main characteristics including open-circuit voltage (VOC) and power conversion efficiency (η) have been evaluated and compared with those of MAPbI3-based cell, in simulation study. The VOC and η of the MAGeI3-based cell (1.18 V and 11.9%) have been found comparable with those of the MAPbI3 one (1.10 V and 14.6%). These results can excite more attention to Ge as a more environment-friendly element than Pb, in highly efficient upcoming perovskite solar cells.
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Compostos de Cálcio , Nanoestruturas , Humanos , ÓxidosRESUMO
A magnetic poly (1,8-diaminonaphthalene)-nickel (PDAN-Ni@Fe3O4) composite as a multifunctional nanocatalyst was prepared in several steps including (I) synthesis of poly (1,8-diaminonaphthalene) (PDAN), (II) modification of PDAN with NiSO4 (PDAN-Ni) and (III) preparation of magnetic nanocatalyst by iron (I and II) salts in the existence of PDAN-Ni complex (PDAN-Ni@Fe3O4). Fourier-transform infrared spectroscopy (FTIR), elemental analysis (CHNSO), vibrating-sample magnetometer (VSM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), field emission scanning electron microscope (FESEM), ultraviolet-visible (UV-vis), and thermogravimetric analysis (TGA) were applied to characterize the prepared nanocatalyst. The PDAN-Ni@Fe3O4 was applied as an environmentally friendly nanocatalyst for the isoxazole-5(4H)-ones synthesis via a one-pot reaction between aryl/heteroaryl aldehyde, hydroxylamine hydrochloride, and ß-ketoester. The nanocomposite was also used for the synthesis of some new alkylene bridging bis 4-benzylidene-3-methyl isoxazole-5(4H)-ones. The catalyst's reusability, and the antioxidant and antibacterial activities of both catalyst and products, were studied. Results showed that the nanocatalyst and isoxazole-5(4H)-ones have antioxidant activity of 75% and 92%, respectively. In addition, the antibacterial test showed that the nanocatalyst and isoxazole-5(4H)-ones have highly active versus Staphylococcus aureus and Escherichia coli bacteria. The reusability and stability of the nanocatalyst, a medium to higher product yield and conversion, a faster reaction time, and the use of green solvents were a few benefits of this study.