Search Results (57)

Illite, a clay mineral, is used in diverse fields such as agriculture, cosmetics, and the food-related industry due to its many advantages, including biocompatibility, UV protection, antibacterial activity, high adsorption capacity for hazardous substances, and cost-effectiveness. However, its relatively large size, broad size distribution, and irregular morphology limit its broader applications. This study investigated the control of particle size and distribution during wet ball milling (WBM) using five media—acetone, ethanol, water, aqueous NaCl solution, and aqueous phosphoric acid solution—over milling times of 2–10 h. Prolonged milling progressively reduced particle size and narrowed the size distribution. Acetone and ethanol exhibited notably superior size-reduction performance compared with the aqueous systems, among which phosphoric acid solution showed the least effectiveness, likely attributed to variations in their physicochemical properties, including viscosity (η) and surface tension (σ), and in their interfacial interactions with illite. Optimal milling in acetone for 10 h resulted in the smallest particles (~700 nm), the narrowest distribution, the largest specific surface area, and the highest moisture retention. Overall, these findings demonstrate that the physicochemical properties of the milling medium, which govern WBM efficiency through fluid dynamics and particle–medium interactions, thereby determine the size and distribution of milled particles. Full article

This manuscript describes the development of a nano-sized synthetic smectic clay hydrogel (LAP) that enables controlled oxygen delivery, making it a promising candidate for treating skin wound infections and promoting healing. LAP is an ingredient in various dermatological products, including powders, creams and emulsions. We investigated the antibacterial effect of the LAP hydrogel by incorporating calcium peroxide (CPO), an oxygen-releasing agent, and measuring the size of the inhibitory halo. We found that CPO hydrogels in LAP showed a significant increase in oxygen release during the first five hours, especially at low CPO concentrations. For example, the hydrogel with 5% CPO showed a controlled release profile with a final percentage oxygen release of 2.47 ± 0.01% after 5 h. In contrast, the hydrogels with 10% and 20% CPO achieved lower final oxygen release values, 0.67 ± 0.01% and 0.75 ± 0.01%, respectively, suggesting that the encapsulation efficiency of LAP is higher at higher concentrations. LAP also proved to be an effective oxygen barrier and showed inherent antimicrobial activity. The research confirmed the antibacterial properties of the hydrogel, with inhibition sites observed against both E. coli and S. aureus. These results emphasize the potential of this hydrogel to serve as an effective tool for wound treatment by providing sustained oxygenation and fighting microbial infections. Full article

Historically, clays have been widely used for the treatment of wounds and to stop hemorrhaging. The aim of this study was to combine four natural clay minerals (kaolinite, glauconite, montmorillonite, and bentonite) with magnetite (Fe₃O₄) nanoparticles to produce Fe₃O₄–clay complexes with enhanced antimicrobial properties and chemopreventive activity against melanoma. The magnetite–clay complexes were synthesized by the chemical co-precipitation method and characterized using XRD, TEM, STEM-EDS, SEM, and SQUID magnetometer. Antimicrobial properties were determined by evaluation of MIC values. The most promising materials were also subjected to direct contact antibacterial test according to the OECD standard for porous materials. Cytotoxicity of the complexes towards melanoma cells and normal human skin fibroblasts was assessed by MTT assay. We performed XRD, which confirmed the formation of Fe₃O₄–clay complex materials. It was also proven that complexes exhibited superparamagnetic properties. Microbiological experiments clearly revealed that modification of natural clays with magnetite significantly boosted their antimicrobial properties. Fe₃O₄–montmorillonite and Fe₃O₄–bentonite showed the strongest antimicrobial activity. Moreover, the mentioned complexes had the ability to reduce the viability of melanoma cells by 35–40%, while exhibiting no cytotoxicity against the normal human fibroblast (BJ) cell line, which is an extremely desirable feature. Thus, it may be concluded that Fe₃O₄–montmorillonite and Fe₃O₄–bentonite complexes hold promise for use in the management of infected wounds and wounds after melanoma excision. Full article

Polyvinylidene fluoride (PVDF) membranes have become a favored choice for membrane filtration because of their outstanding mechanical characteristics, chemical resistance, thermal stability, and ease of handling. Nevertheless, the hydrophobic nature of PVDF membranes can result in fouling, which diminishes their efficiency over time. This study explores the impact of ZnO-Nanoclay on the properties and performance of mixed matrix membranes made from polyvinylidene fluoride (PVDF) at different loading percentages (0, 1, and 3 wt%). The ZnO-Nanoclay nanoparticles were synthesized using environmentally friendly methods, characterized, and blended into PVDF matrices via a solution-casting technique, resulting in a series of membranes. The synthesized nanoparticles were analyzed using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The resulting mixed-matrix membranes underwent comprehensive analyses to assess their structure and surface properties, employing SEM, XRD, Atomic Force Microscopy (AFM), and contact-angle measurements. Furthermore, tensile, antibacterial, and barrier properties were evaluated. Integrating ZnO-Nanoclay into PVDF membranes greatly improves antifouling properties, achieving inhibition rates of 99.92% at a clay-loading percentage of 3 wt% and increasing water-flux rates by 16% compared to pure PVDF membranes at 1 wt%. In addition, ZnO-Nanoclay nanoparticles significantly boost the mechanical properties of PVDF membranes, enhancing maximum strength by 500% at 3 wt% loading. This study examines the interplay between the structure, properties, and performance of mixed-matrix membranes by comparing different PVDF membranes that were mixed with different nanoclay composites, providing significant insights into improving these membranes through the incorporation of nanoclay composites to enhance their overall properties and effectiveness. Full article

The propolis produced by stingless bees is a complex mixture of natural sticky components mixed with soil or clay. Global research on propolis has focused on studying the biological and pharmacological properties and chemical composition of stingless bee propolis from Brazil, Indonesia, and other regions. However, studies of stingless bee propolis produced in Mexico are scarce. This study aimed to determine the chemical composition of the geopropolis of Scaptotrigona mexicana collected in the Totonacapan region and to evaluate its antioxidant and antibacterial activities. The phenolic contents of the ethanolic extract of the collected propolis ranged from 2.45 ± 0.03 mg GAE/g to 3.48 ± 0.56 mg GAE/g of dry extract. The total flavonoid content ranged from 0.69 ± 0.03 mg QE/g to 0.84 ± 0.009 mg QE/g of dry extract. The antioxidant activity of the ethanolic extracts was assessed via DPPH, ABTS, and FRAP assays. The minimum inhibitory concentration values exhibited by the ethanolic extract (>512 g/mL) for Gram-negative bacteria (Pseudomonas aerugunosa and Phorphyromonas gingivalis) were higher than those of Gram-positive bacteria. The stingless bee propolis extract showed the highest antibacterial activity against Streptococcus mutans (256 g/mL). Five known compounds, taraxeryl acetate (1), lupeol (3), cicloart-23-en-3β,25-diol (5), mangiferoic acid (6), and 5-(11’Z-heptadecenyl)-resorcinol (7), and two irresoluble mixtures of 3-O-acetyl-α-(2a) and 3-O-acetyl-β-amyrins (2b), and α- (4a) and -amyrins (4b), were identified by nuclear magnetic resonance spectroscopy and mass spectrometry. Additionally, 39 volatile compounds were identified via headspace-solid phase microextraction using the hyphenated gas chromatography coupled to mass spectrometry time-of-flight. The main volatile compounds detected include trans-α-bergamotene (8.15%), hexanal (7.17%), 2-heptanone (7.60%), and α-copaene (7.09%). Full article

Indigo leaves from various plant species are sources of dyes/pigments, not fully exploited for making sustainable textiles. Blue indigo vat dye extracted from indigo leaves yields high wash color fastness but fades slowly with light, and is not easily used for direct printing. Indigo leaves can be used to produce textiles of various color shades, while light-resistant Mayan-inspired hybrid pigments have not yet been used for textile coloring. Using blue indigo dyes from three plant species, with exhaustion dyeing, intense wash-resistant blue-colored textiles are produced, and in the case of Indigofera Persicaria tinctoria, textiles have antibacterial activity against S. epidermis and E. coli. A 100% natural Mayan-inspired blue indigo pigment, made from sepiolite clay and natural indigo dye, was used both in powdered and paste forms to perform pigment textile dyeing by pad cure process, and direct screen printing on textiles. A water-based bio-binder was used efficiently for both padding and printing. Bio-based Na Alginate thickener allowed to produce prints with good color-fastness on both polyester and cotton fabrics, while bio-based glycerin produced excellent print color fastness on polyester only: wash fastness (5/5), dry and wet rub fastness (5/5) and light fastness (7/8). Full article

Clay minerals are actively used to obtain a bioactive composite. Kaolinite, as a representative of clay minerals, possesses unique properties essential for the creation of biocomposite materials. This mineral, characterized by its distinctive layered structure, is chemically inert, highly stable, thermally resistant, eco-friendly, biocompatible, and non-toxic. Kaolinite, which plays the role of a carrier in this work, has such properties and can be the basis for biologically active composites. Antibacterial composites, namely, kaolinite/chlorhexidine and kaolinite/triclosan, were synthesized by impregnation of calcined and non-calcined samples of natural kaolinite with the antibacterial agents chlorhexidine and triclosan. The structure, morphology, elemental composition, and mineralogical characteristics of the natural and synthesized kaolinite/chlorhexidine (KAO/CHX) and kaolinite/triclosan (KAO/TCS) composites were investigated by methods of analysis such as X-ray diffraction, FTIR (Fourier-transform infrared) spectroscopy, and scanning electron microscopy. The calcined kaolinite/chlorhexidine composite at 500 °C (KAO_500°C/CHX) exhibited a higher content of antiseptics compared to the non-calcined kaolinite composite. The antibacterial activities of the kaolinite/chlorhexidine and kaolinite/triclosan composites were investigated against Gram-positive Staphylococcus epidermidis and Gram-negative Klebsiella pneumoniae and Escherichia coli strains by the well diffusion method and dilution method. The highest zone of inhibition was observed against Staphylococcus epidermidis (30.00 ± 0.00 mm and 30.67 ± 0.58 mm) by applying KAO/TCS and KAO_500°C/TCS via the well diffusion method. The minimum bactericidal concentration of the kaolinite/TCS composite was 15.63 μg/mL for Staphylococcus epidermidis and Klebsiella pneumoniae. Full article

The aim of this review is to analyze natural substances exhibiting antibacterial and antifungal activity against skin pathogens, along with their exemplary applications in cosmetic products. Growing concerns related to increasing infection rates and pathogen resistance have prompted the search for alternative therapeutic methods. This article discusses various natural products, derived from plants, animals, and minerals, with antimicrobial potential. Special attention is given to the antimicrobial efficacy of natural substances derived from Allium L., Salvia L., Lavandula L., Origanum L., Melaleuca alternifolia, Aloe vera, Black Cumin, and Trigonella L. in improving treatment outcomes, either alone or in combination with conventional medications. In addition, the presented natural products, such as propolis, honey, cosmetic mud, and clays, can serve as viable alternatives or complementary treatments for mild skin infections and may help prevent recurrence. The promising potential of these natural products encourages further research into discovering new antimicrobial agents. However, the lack of standardization of natural preparations can result in inconsistent therapeutic effects and unforeseen side effects. This review significantly contributes to the pharmaceutical and cosmetic industries by emphasizing the potential of natural products and highlighting the need for further research and regulatory measures to ensure their safe and effective integration with existing therapies. Full article

Silver nanoparticles are one of the most commonly used forms of silver (Ag) in nanotechnology applications due to their antibacterial properties and electrical and thermal resistance. The increasing production and use of products containing nanoparticles has led to their release into and contamination of soil and water. This review summarizes the literature on the fate, behavior (adsorption/desorption, precipitation/oxidative dissolution, transformation), and transport/mobility of Ag forms in soils (Ag⁺ ions and Ag nanoparticles—AgNPs). The behavior of Ag⁺/AgNPs in soil is a complex process. It depends on many factors, including the characteristics of the Ag forms (ions, nanoparticle size, ligand type used for coating, surface charge, initial Ag concentration), the soil properties (organic matter and clay mineral content, textural properties, point of zero charge, cation exchange capacity, surface functional groups), and the solute properties (pH–Eh, ionic strength, cation type, oxygen content). The binding of Ag⁺ and AgNPs is significantly positively correlated with Al/Fe/Mn oxide and SOM content and depends on the surface charge of the minerals and CEC, which controls adsorption processes. Very important parameters to consider are the pH and Eh of the solution, which determine the durability of the ligands, the aggregation rate and the oxidation process of AgNPs, as well as the presence of sulfide and chloride and the Cl/Ag ratio, which determine the stability/mobility of Ag. Since AgNPs can be oxidized to Ag⁺ ions during their life cycle, it is necessary to consider the behavior of both forms of Ag in soils. Understanding the transport and behavior of Ag in soil is essential for the environmental risk assessment and management of wastes containing Ag. Full article

Polymers of natural origin, such as representatives of various polysaccharides (e.g., cellulose, dextran, hyaluronic acid, gellan gum, etc.), and their derivatives, have a long tradition in biomedical applications. Among them, the use of chitosan as a safe, biocompatible, and environmentally friendly heteropolysaccharide has been particularly intensively researched over the last two decades. The potential of using chitosan for medical purposes is reflected in its unique cationic nature, viscosity-increasing and gel-forming ability, non-toxicity in living cells, antimicrobial activity, mucoadhesiveness, biodegradability, as well as the possibility of chemical modification. The intuitive use of clay minerals in the treatment of superficial wounds has been known in traditional medicine for thousands of years. To improve efficacy and overcome the ubiquitous bacterial resistance, the beneficial properties of chitosan have been utilized for the preparation of chitosan–clay mineral bionanocomposites. The focus of this review is on composites containing chitosan with montmorillonite and halloysite as representatives of clay minerals. This review highlights the antibacterial efficacy of chitosan–clay mineral bionanocomposites in drug delivery and in the treatment of topical skin infections and wound healing. Finally, an overview of the preparation, characterization, and possible future perspectives related to the use of these advancing composites for biomedical applications is presented. Full article

Edible films based on biopolymers are used to protect food from adverse environmental factors. However, their ample use may be hindered by some challenges to their mechanical and antimicrobial properties. Despite this, in most cases, increasing their mechanical properties and antibacterial activity remains a relevant challenge. To solve this problem, a possible option is to fill the biopolymer matrix of films with a functional filler that combines high reinforcing and antibacterial properties. In this work, biocomposite films based on a mixture of chitosan and cassava starch were filled with a hybrid filler in the form of bentonite clay particles loaded with ginger essential oil (GEO) in their structure with varied concentrations. For this purpose, GEO components were intercalated into bentonite clay interlayer space using a mechanical capture approach without using surface-active and toxic agents. The structure and loading efficiency of the essential oil in the obtained hybrid filler were analyzed by lyophilization and laser analysis of dispersions, ATR-FTIR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The filled biocomposite films were analyzed using ATR-FTIR spectroscopy, optical and scanning electron spectroscopy, energy dispersive spectroscopy, mechanical analysis under tension, and the disk diffusion method for antibacterial activity. The results demonstrated that the tensile strength, Young’s modulus, elongation at the break, and the antibacterial effect of the films increased by 40%, 19%, 44%, and 23%, respectively, compared to unfilled film when the filler concentration was 0.5–1 wt.%. Full article

The study examined the possibility of intercalation of montmorillonite with neomycin in an aqueous drug solution and the factors influencing the effectiveness of this process, such as the ion exchange capacity and process conditions, including the time and temperature of incubation with the drug. X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermal analysis (DSC/TG), and Zeta potential measurement were used to confirm drug intercalation as well as to investigate the nature of clay–drug interactions. The obtained conjugates with the most favorable physicochemical properties were also tested for antibacterial response against Gram-negative bacteria (Escherichia coli) to confirm that the bactericidal properties of neomycin were retained after intercalation and UV–VIS spectrophotometry was used to examine the kinetics of drug release from the carrier. The results of the conducted research clearly indicate the successful intercalation of neomycin in montmorillonite and indicate the influence of process parameters on the properties of not only the conjugates themselves but also the properties of the intercalated drug, particularly its bactericidal activity. Ultimately, a temperature of 50 °C was found to be optimal for effective drug intercalation and the conjugates obtained within 2 h showed the highest antibacterial activity, indicating the highest potential of the thus-obtained montmorillonite conjugates as neomycin carriers. Full article

Carvacrol and thymol are broad-spectrum natural antimicrobial agents. To reduce their volatility and improve their antimicrobial performance, synergistic systems were prepared loading the active molecules in zinc-modified clays. Montmorillonite (MMT) and zeolite (ZEO) were modified with zinc ions (ZnMMT and ZnZEO), with well-known antimicrobial properties, and then with carvacrol or thymol, reaching the 26 ± 3% and 33 ± 2% w/w of loading, respectively. The resulting hybrid materials were characterized by FT-IR, XPS, XRD, TGA, and GC-MS to evaluate carvacrol/thymol release in simulating food matrices. Antimicrobial assays carried out using spoiler and pathogenic bacterial strains showed that the antimicrobial activity of both thymol and carvacrol was largely preserved once they were loaded into Zn-modified clays. However, MMT hybrids showed an antibacterial activity significantly higher than ZEO hybrids at 50 mg/mL of thymol and carvacrol. For this reason, deeper antimicrobial evaluations were carried out only for ZnMMT composites. ZnMMT loaded with thymol or carvacrol produced inhibition zones against most of the target strains, also at 3.12 mg/mL, while the positive controls represented by the single molecule thymol or carvacrol were not active. The hybrid materials can be useful for applications in which the antimicrobial activity of natural molecules need to be displayed over time as requested for the control of microbial pathogens and spoilage bacteria in different applications, such as active packaging, biomaterials, and medical devices. Full article

Natural clay minerals are among the most versatile materials used in the biomedical field. Palygorskite has found various applications in this field, from the treatment of diarrheal diseases in the past to materials with antibacterial properties and platforms carrying bioactive compounds used in the treatment of diseases, cosmetic and healthcare products in the present. In this study, a possible delivery method of some bioactive asymmetric β-diketonic compounds is presented. Palygorskite modified with amphionic groups (P) and copper ions (PCu) was used as a platform to load bioactive curcumin derivatives (1 and 2). By varying the copper ions, the amounts of charged active compounds were monitored. Studies have shown that the hybrid materials resulting from the loading of 1 and 2 compounds on palygorskite with 30% copper ions (PCu₃₀) can be used as delivery methods for these asymmetric curcumin derivatives, while palygorskite with 50% copper ions(PCu₅₀) loaded with the same type of bioactive compounds has antibacterial properties. Full article

The continuous discharge of organic dyes into freshwater resources poses a long-term hazard to aquatic life. The advanced oxidation Fenton process is a combo of adsorption and degradation of pollutants to detoxify toxic effluents, such as anti-bacterial drugs, antibiotics, and organic dyes. In this work, an activated attapulgite clay-loaded iron-oxide (A-ATP@Fe₃O₄) was produced using a two-step reaction, in which attapulgite serves as an enrichment matrix and Fe₃O₄ functions as the active degrading component. The maximum adsorption capacity (q_t) was determined by assessing the effect of temperature, pH H₂O₂, and adsorbent. The results showed that the A-ATP@Fe₃O₄ achieves the highest removal rate of 99.6% under optimum conditions: 40 °C, pH = 3, H₂O₂ 25 mM, and 0.1 g dosage of the composite. The dye removal procedure achieved adsorption and degradation equilibrium in 120 and 30 min, respectively, by following the same processes as the advanced oxidation approach. Catalytic activity, kinetics, and specified surface characteristics suggest that A-ATP@Fe₃O₄ is one of the most promising candidates for advanced oxidation-enrooted removal of organic dyes. Full article