Antibacterial Assay Research Articles

Studies on the Bioactive Components and Antibacterial Activities of Kigelia Africana

Objective: Nature has been a source of medicinal agents for thousands of years and an impressive number of modern drugs have been isolated from natural sources. K. africana is a plant which various part have been used as antibacterial agents, antiprotozoal agents, antineoplastic agents, CNS stimulants e.t.c. Method: Fresh leaves and stem bark of K. africana were collected from Egugwu Agbaja Izzi LGA, Ebonyi State. The plant was washed, soaked, filtered and air-dried to get the aqueous extract. Semi quantitative phytochemical identification, Gas chromatography/Mass spectrometry as well as antibacterial assays of the extracts against C. freundii, E. coli, K. pneumonia and S. aureus by agar well diffusion method were carried out. The aqueous extracts were re-extracted to obtain an ethanolic fraction. Result: The aqueous extract of the leaf had more inhibitory effects than that of the stem bark on the test organisms. The aqueous extract had more inhibitory effects against S. aureus, K. pneumonia and C. freundii as compared to E. coli. The ethanolic fraction had a very significant (P˂0.05) inhibitory effect against all the test organism. Phytochemical analysis of the crude extracts showed the presence of glycosides, tannins, carbohydrate resin and reducing sugar in all extract while saponin and flavonoid was noted only in the aqueous extract of K. africana stem bark. The GC/MS revealed the presence of acetic acid, hydroxy-ethyl ester e.t.c in the leaf aqueous extract whereas phenol, 3-methoxy-2,4,6-trimethyl was revealed in the stem bark. Conclusion: This study revealed that aqueous extract of K. africana contains high amount of phyoconstituents and it may be responsible for its good antibacterial activity.

Development and evaluation of biodegradable alginate beads loaded with sorafenib for cancer treatment

The study focused on fabricating and characterizing sorafenib-loaded calcium alginate beads for potential cancer therapy application. The beads were synthesized via ionotropic gelation using calcium chloride as a crosslinker. Successful sorafenib encapsulation was confirmed through various analytical techniques, including FTIR, XRD, SEM, and UV-Vis spectroscopy. FTIR analysis showed shifts in characteristic bands, indicating effective drug loading. XRD patterns revealed both amorphous and crystalline characteristics, with peaks corresponding to the drug and polymer. SEM images depicted spherical beads with surface roughness. UV-Vis spectrum analysis demonstrated high encapsulation efficiencies ranging from 99.48 % to 99.82 %, depending on the sorafenib concentration. Biodegradation studies suggested the beads' potential for drug delivery, showing gradual weight and shape loss. Antioxidant assays indicated superior scavenging activity, while antibacterial assays showed good activity against Bacillus species. Cytotoxicity studies revealed specific toxicity against MCF7 breast cancer cells. Drug release data fitted well with the first-order model, indicating controlled release properties. These findings highlight the potential of sorafenib-loaded calcium alginate beads as an effective delivery system for cancer therapy.

Green synthesis of copper oxide nanoparticles via Moringa peregrina extract incorporated in graphene oxide: evaluation of antibacterial and anticancer efficacy.

This research investigated the physicochemical properties and biological activities of green-synthesized copper oxide nanoparticles (CuO NPs) via Moringa peregrina extract, graphene oxide (GO), and their composite (CuO-GO). SEM revealed the morphology and structure, indicating polygonal CuO NPs, thin wrinkled sheets of GO, and a combination of CuO NPs and GO in the nanocomposite. EDS confirmed the elemental composition and distribution. XRD analysis confirmed the crystalline monoclinic structure of CuO NPs and GO, as well as their composite, CuO-GO, with characteristic peaks. DLS analysis exhibited distinct size distributions, with CuO NPs showing the narrowest range. BET surface area analysis revealed mesoporous structures for all materials, with the nanocomposite showing enhanced surface area and pore volume. Anticancer assays on MCF-7 and normal NIH/3T3 cells demonstrated CuO-GO's superior cytotoxicity against cancer cells, with minimal effects on normal cells, suggesting selective cytotoxicity. Moreover, antibacterial assays against Pseudomonas aeruginosa and Staphylococcus aureus indicated CuO-GO's potent inhibitory activity. The composite's synergistic effects were evidenced by its lower minimum inhibitory concentration (MIC) compared to individual components. In conclusion, this study elucidated the promising biomedical applications of CuO NPs, GO, and their nanocomposite, particularly in cancer treatment and antibacterial therapies, showcasing their potential as multifunctional nanomaterials.

Physicochemical characterization of novel okra mucilage/hyaluronic acid-based oral disintegrating films for functional food applications

Oral disintegrating films (ODFs) offer a patient-friendly approach with enhanced convenience and rapid onset of action over various health benefits. ODFs are fabricated for geriatric, pediatric, and individuals facing swallowing challenges. The present work aims to fabricate and characterize ODFs mainly composed of okra mucilage (OM), hyaluronic acid (HA), vitamin-C-loaded bioactive glass nanoparticles (VBG NPs), and clove essential oil. A bio-inspired method was employed to synthesize VBG NPs using fructose template. The nutrient analysis of OM depicted that it is a rich source of protein, carbohydrates, magnesium, and flavonoids (quercetin), accounting for its antioxidant activity. The physicochemical characteristics of the ODFs studied using contact angle measurement, surface pH, opacity, and in vitro disintegration time revealed that ODFs disintegrated rapidly in simulated saliva. The neutral surface pH of ODFs indicates their non-irritant behaviour to the oral mucosa. VBG NPs and essential oil (EO) addition enhance the thermal and mechanical properties. Further, EO infusion in the film matrix resulted in the porous and antibacterial nature of the functional film as revealed by FE-SEM micrographs and antibacterial disk diffusion assay respectively. The obtained novel nutrient-rich ODF is hemocompatible with a hemolysis rate (HR%) <5 % and suitable for functional food applications.

Enhanced osteogenesis and antibacterial activity of dual-functional PEEK implants via biomimetic polydopamine modification with chondroitin sulfate and levofloxacin

Polyetheretherketone (PEEK) implants have emerged as a clinically favored alternative to titanium alloy implants for cranial bone substitutes due to their excellent mechanical properties and biocompatibility. However, the biological inertness of PEEK has hindered its clinical application. To address this issue, we developed a dual-functional surface modification method aimed at enhancing both osteogenesis and antibacterial activity, which was achieved through the sustained release of chondroitin sulfate (CS) and levofloxacin (LVFX) from a biomimetic polydopamine (PDA) coating on the PEEK surface. CS was introduced to promote cell adhesion and osteogenic differentiation. Meanwhile, incorporation of antibiotic LVFX was essential to prevent infections, which are a critical concern in bone defect repairing. To our delight, experiment results demonstrated that the SPKD/CS-LVFX specimen exhibited enhanced hydrophilicity and sustained drug release profiles. Furthermore, in vitro experiments showed that cell growth and adhesion, cell viability, and osteogenic differentiation of mouse calvaria-derived osteoblast precursor (MC3T3-E1) cells were significantly improved on the SPKD/CS-LVFX coating. Antibacterial assays also confirmed that the SPKD/CS-LVFX specimen effectively inhibited the growth of Escherichia coli and Staphylococcus aureus, attributable to the antibiotic LVFX released from the PDA coating. To sum up, this dual-functional PEEK implant showed a promising potential for clinical application in bone defects repairing, providing excellent osteogenic and antibacterial properties through a synergistic approach.

Characteristics and functional analysis of a novel mannose receptor in Penaeus vannamei

The mannose receptor (MR) plays a key role in the innate immune system as a pattern recognition receptor. Here, a novel type of mannose receptor, named PvMR2, was identified from Penaeus vannamei (P. vannamei). The PvMR2 coding sequence (CDS) obtained was 988 base pairs in length, encoding a protein consisting of 328 amino acids. This protein includes a signal peptide and two classical C-type lectin domains (CTLD). Quantitative real-time PCR showed that PvMR2 was distributed in all detected tissues, with the highest levels in the intestines and stomach. Following a bacterial challenge with Vibrio anguillarum (V. anguillarum), PvMR2 showed significant up-regulation in both the intestines and stomach of shrimp. To validate the function of PvMR2, recombinant proteins were extracted and purified using a His-tag. The resulting rPvMR2 demonstrated binding capability with lipopolysaccharides (LPS) and peptidoglycan (PGN) in a dose-dependent manner, affirming its binding affinity. The purified rPvMR2 demonstrated calcium-independent binding activity towards both Gram-positive bacteria (V. anguilliarum and Vibrio parahaemolyticus) and Gram-negative bacteria (Escherichia coli and Aeromonas Veronii). Antibacterial assays confirmed that rPvMR2 inhibits bacterial growth. Intestinal adhesion and adhesion inhibition experiments confirmed that the rPvMR2 can be used to reduce the adhesion capacity of harmful bacteria in the gut. Phagocytosis experiments have shown that rPvMR2 promotes phagocytosis in hemocytes and protects the host from external infection. Treatment with recombinant PvMR2 significantly bolstered bacterial clearance within the hemolymph and markedly augmented shrimp survival post-infection with V. anguillarum. These results suggest that PvMR2 has agglutination, growth inhibition, adhesion inhibition, clearance promotion, and phagocytosis effects on harmful bacteria, and plays a crucial role in the antimicrobial immune response of P. vannamei.

Effects of geographical variation on the phytochemicals gallic acid, corilagin, and ellagic acid, as well as medicinal properties of Emblica officinalis Gaertn (Fruit)

Geographical variation can significantly influence the abundance and distribution of phytochemicals within the raw drug, which in turn may affect its medicinal efficacy and potential health benefits. Understanding these variations is crucial for optimizing cultivation practices and harnessing the full therapeutic potential of herbal raw drug. Owing to the lack of availability of the comprehensive study on the effects of geographical variation on phytochemicals & micronutrient content and antioxidant & antibacterial potential of Emblica officinalis (EO), in the current study, EO fruit samples from different terrestrial regions of India were analyzed to identify variations in certain phytochemicals and nutrients content. A broad study including the identification, substantiation and phytochemical analysis of EO has been performed via a validated HPLC method. The complete profiling of various volatile metabolites present in the sample has been done by GC-MS/MS technique. The observed range of phytochemicals present in different EO samples using validated HPLC-DAD method are 4.38 to 69.41 mg/g for Gallic acid, 0.50 to 5.54 mg/g for Corilagin and 3.92 to 15.34 mg/g for ellagic acid. The total phenolic content (TPC) and total flavonoid content (TFC) for different samples of EO ranged from 52.86–175.47 mg GAE/g of wt. and 1.28–13.88 mg QCE/g of wt. respectively. ICP-OES analysis depicts substantial amount of various essential micronutrients such as Fe, Cu, Mn and Zn. In antibacterial assay, methanolic extracts of EO obtained from Pune zone exhibited promising activity against S. aureus, S. typhi and MRSA strains with inhibition zones of 28, 23 and 28 mm, respectively. Further, the antioxidant, antidiabetic and anti-inflammatory activities of EO on the basis of analyzed phytochemicals have also been evaluated through molecular docking study.

In vitro and in vivo evaluation of the layer-by-layer vancomycin with poly(ε-caprolactone) nanosphere-coated Schanz pins for prolonged release

In this research, the effect of layer-by-layer (spray and dip) coating followed by annealing of vancomycin (VCM) and poly(ε-caprolactone) nanospheres (PCLnp) on Schanz pins for prolonged antibacterial activity was investigated. Nanospheres were prepared using the high-pressure homogenizer method and characterized by both functional groups and particle size. The in vitro release profile revealed that after 28 days, the cumulative release of VCM from the VCM-PCLnp coated pins was 753.68 ± 0.19 μg. The coated pins released VCM at a concentration greater than the minimum inhibitory concentration (MIC) and sustained this release for 28 days. Irritation, hemolysis, sensitization, and cytotoxicity assays confirmed that VCM-PCLnp coated pins were highly biocompatible. Additionally, antibacterial assays against methicillin-resistant Staphylococcus aureus (MRSA) revealed prolonged antibacterial resistance. Specifically, the assays demonstrated effective inhibition of Staphylococcus aureus (S. aureus), including the methicillin-resistant strain. This approach involves coating the implants with antibiotics and polymeric nanospheres using a layer-by-layer (dip and spray) method to prolong their antibacterial activity. The results of this study show great promise for successfully treating implant-associated infections. Consequently, we recommend this method for coating other medical devices.

Synthesis and Antibacterial Activity of Capsaicin Derivatives Containing Phenolic Hydroxyl Groups

AbstractBacterial infections tend to cause a series of cytopathic reactions and have become a major threat to human life. Among them, phenolic compounds are widely used as a natural antibacterial derivative for antifouling and antibacterial applications. In this study, four phenolic hydroxyacrylamide monomers have been successfully prepared using capsaicinoid derivatives as inspiration (named as OHABA, PHABA, AHMA, and AMTHBA, respectively) and the chemical structures were confirmed by FT‐IR, 1H‐NMR, 13C‐NMR. The minimum inhibitory concentration (MIC) assay and plate antibacterial assay were measured to explore the antibacterial properties of the monomer. The results showed that four capsaicin derivatives exhibited antibacterial activity, and the antibacterial properties of the four monomers from strong to weak were PHABA, OHABA, AHMA and AMTHBA. The best antibacterial activity was PHABA (MIC for E. coli: 1.6 mg/mL, bacteriostasis rate: 82.46 %, MIC for S. aureus: 1.6 mg/mL, bacteriostasis rate: 69.58 %). Both the cluster effect of monomers and the spatial distribution of phenolic hydroxyl groups in the structure of derivatives affect the antibacterial properties.

Alginate Cryogels for Rapid Hemostasis and Toluidine Blue-Mediated Photodynamic Inactivation of Bacteria.

The development of new wound dressings with fast hemostatic and bactericidal properties for prehospital care is critical. Antibacterial photodynamic therapy (aPDT) has attracted attention due to its broad-spectrum antibacterial activity and minimal bacterial resistance. However, photosensitizers used in aPDT often face issues such as poor water solubility, short-lived singlet oxygen (1O2), and limited 1O2 diffusion range. In this study, sodium alginate was covalently modified with the photosensitizer toluidine blue O (TBO) and phenylboronic acid (PBA). The modified alginate was then cross-linked with Ca(II) ions and lyophilized to form a cryogel, named SA@Ca(II)@TBO@PBA (SCTP). This cryogel functions as an antibacterial photodynamic wound dressing. The chemical immobilization of TBO and PBA enhanced the cryogel's targeting ability. PBA formed reversible covalent bonds with diol groups on bacterial cell surfaces, allowing the cryogel to capture bacteria effectively and enhance aPDT. The bactericidal efficiency of the cryogel was tested through in vitro antibacterial assays, and its hemostatic properties were confirmed in vivo. The results indicate that this cryogel has excellent hemostatic and antibacterial capabilities, showing great promise as a wound dressing for clinical applications.

Study on the characteristics of novel fiber extracted from Foxtail palm fruits – A steps towards the sustainable development

This study explores the properties of fibers extracted from the fruits of the Foxtail palm (FPF) and assesses their potential for advancing sustainable development. Antibacterial assays demonstrated that these fibers significantly inhibit the growth of gram-negative bacteria, including Pseudomonas aeruginosa and Salmonella enterica, with inhibition zones of 24 mm and 30 mm, respectively. X-ray diffraction analysis revealed a predominantly crystalline structure, which is crucial for use as reinforcing materials, showing distinct peaks at 20° and 30° diffraction angles that signify the presence of cellulose I. Fourier-transform infrared spectroscopy confirmed the fibers’ complex composition of cellulose, hemicellulose, and lignin, indicated by the presence of hydroxyl, carbonyl, and aliphatic functional groups. Scanning electron microscopy analysis showed a rough and irregular surface texture adorned with numerous microfibrils and cavities, which are beneficial for mechanical interlocking with polymer matrices. The densely arranged cellulose microfibrils, approximately 210 µm in diameter, lend the fibers high tensile strength and stiffness. Although some surface imperfections were observed, the inherent porosity of the fibers facilitates resin absorption, enhancing their reinforcement capabilities in composite materials.

Bioinspired green synthesis of copper, nickel, and hybrid nanoparticles using Myristica Fragrans seeds: Biomedical applications and beyond

Nanotechnology focuses on materials at the molecular and atomic levels, with sizes ranging from 0.1 to 100 nm. This study explores the synthesis and characterization of copper oxide (CuO), nickel oxide (NiO), and hybrid nanoparticles using an aqueous seed extract from Myristica fragrans. The nanomaterials underwent comprehensive characterization employing various techniques: UV analysis, FTIR spectroscopy, XRD, TGA, EDX and SEM. We explored their biological applications through antioxidant and antibacterial assays. UV analysis determined the optical absorption spectra values for CuO, NiO and hybrid nanoparticles. FTIR analysis confirmed functional groups in the plant extract responsible for capping and reducing the reaction medium. XRD and SEM analysis demonstrated the crystalline nature and morphology of the nanoparticles. CuO nanoparticles exhibited polyhedral morphology, while NiO nanoparticles were primarily spherical with some agglomeration. The CuO-NiO hybrid nanoparticles showed a wurtzite morphology with significant agglomeration and larger mean size than CuO and NiO nanoparticles. EDX indicated higher quantities of Cu and Ni. XRD spectra revealed the average particle sizes of nanoparticles. TGA indicated the thermal stability of the nanoparticles, with hybrid nanoparticles being the most stable. The nanoparticles exhibited excellent antioxidant activity, with hybrid nanoparticles showing the highest values in measuring total antioxidant capacity, total reducing power (TRP), ABTS assay, and DPPH-free radical scavenging assay at 400 μg/mg. Antibacterial assays against multidrug-resistant bacterial strains demonstrated that antibiotics-coated hybrid nanoparticles exhibited potent antibacterial properties against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. In conclusion, CuO, NiO, and CuO-NiO hybrid nanoparticles mediated by Myristica fragrans showcase promising characteristics for various applications, especially in biomedical and clinical settings. The nanoparticles eco-friendly synthesis and biocompatible nature make them attractive candidates for future research and development.

Molecular Docking, Acute Toxicity and Antibacterial Study of Debilon and Phorbasterone-B Extracted from Rhodophyta

Introduction: Natural compounds obtained from marine algae, especially Rhodophyta are now being investigated for various biological activities. However, the antimicrobial activity and toxicity profile of compounds present in these algae isunderexplored. Objective: This study procured two compounds, Debilon and Phorbasterone-B, from Rhodophyta to analyze their in silico and in vitro potential against pathogenic bacterial strains and their acute toxicity. Methods: Debilon and Phorbasterone-B were extracted from Rhodophyta by a previously reported method and were further subsequently exploited computationally for their physicochemical properties, prediction of biological activity and molecular docking against bacterial proteins, toxicity, and experimentally for antibacterial potential against pathogenic strains of Vibrio cholera, Salmonella typhi, Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. Results: Docking studies proved that these molecules possess a chemical affinity for the bacterial proteins and can inhibit the growth of these microorganisms, as confirmed by antibacterial assay. Whereas the prediction analysis and toxicity studies showed that the friendliness of these molecules to the human body is enormous. Conclusion: From this study, it has been proved that DN and PB are perfect candidates for inhibiting these bacterial strains.

Waste-derived Ca and Zn-based bimetallic (Ca/Zn) nanorods encapsulated chitosan-based haemostatic dressing bandage: A step towards waste to bandages

Controlling loss of blood during militant war, traumatic injury, and surgical procedures is the greatest challenge nowadays, which leads to death, thereby the necessity of hemostatic bandages. The present work focuses on the synthesis of waste-derived (WD)-Ca incorporated Zn nanorods encapsulated with chitosan polymers (CZC) to control the loss of blood as well as bacterial infection. The as-prepared CZC bandage was tested against various biochemical tests such as PBS absorption, hemolysis, adsorption of protein, platelets aggregation/adhesion, blood clotting ability, and antibacterial test assay. The data suggested that the CZC bandage has high biocompatibility, exceptional PBS absorption ability (∼1402%), platelets aggregation (∼65%) within 10 min of exposure, protein a loading ability (∼37 mg/cm2), and ∼84% blood clotting within a 1 min of exposure. Moreover, the CZC bandage effectively kills/inhibits both E. Coli and S. aureus bacteria. Therefore, the prepared CZC bandage in this study is simple, economically viable, and sustainable development.

Valorizing recycled paper through chitosan and glyoxal-chitosan treatments: Synergistic effects on mechanical and physical properties

The present study investigates the efficacy of chitosan and glyoxal-crosslinked chitosan (Chi-Gly) as reinforcing agents for enhancing the mechanical, physical, and functional properties of recycled paper. The research aims to evaluate the comparative performance of these two forms of chitosan in imparting strength characteristics and improved functionality to recycled paper substrates. Chitosan and Chi-Gly solutions prepared via glyoxal crosslinking were incorporated into recycled pulp suspensions at varying dosages. Laboratory handsheets were fabricated, and their properties were systematically evaluated through mechanical testing, morphological analysis, wettability measurements, and antibacterial assays. The results demonstrated significant improvements in the tensile index, burst index, and bending resistance for the chitosan and Chi-Gly treated papers, with the Chi-Gly exhibiting superior reinforcement. Notably, the Chi-Gly treated paper exhibited a higher wet tensile index and lower water absorption capacity than the control. SEM analysis revealed a denser, more cohesive fiber network facilitated by chitosan and Chi-Gly, aiding the reinforcement. The treated papers exhibited reduced hydrophobicity and pronounced antibacterial activity against E. coli (a gram-negative bacterium) and S. aureus (a gram-positive bacterium), with the Chi-Gly treatment outperforming chitosan. Notably, the treatments improved the functional properties without negatively impacting optical brightness. The findings highlight the synergistic effects of glyoxal crosslinking on chitosan’s reinforcing ability and the potential of these biopolymers as sustainable and multifunctional additives for the recycled paper industry.

Terbium (III) and salicylamide doped nickel ferrite (NiFe2O4) nanoparticles synthesized from Olea europaea L. plant extracts via eco-friendly green synthesis approach and co-precipitation method

An eco-friendly and cost-effective NiFe2O4 nanoparticles and its derivatives NiFe2O4:salicylamide, NiFe2O4:salicylamide:Tb3+ and NiFe2O4:salicylamide:Tb3+:Olea europaea L. extracts have been successfully synthesized using a simple and refluxed-assisted chemical co-precipitation method and green route approach followed by thermal treatment steps. In this report, the structural, morphological, optical characteristics and biological activities of the nanoparticles were characterized by using XRD, SEM, FTIR, UV-Vis, PL, BET analysis, antibacterial assays and antioxidant activities. The results from XRD revealed that NiFe2O4 has a crystalline structure and EDX elemental mapping confirmed the uniform distributed of all the elements in the matrix. The incorporation of salicylamide, Tb3+ and Olea europaea L. extracts into NiFe2O significantly enriched the luminescence intensities and changed the emission colour coordinates. Colour tunability was achieved with luminescence ranging from bright blue emission to reddish orange light, which makes nanoparticles important candidates for solid-state lighting technologies. Combining olive leaf extracts with NiFe2O4 nanoparticles provided effective antioxidant and antibacterial activity by reducing and stabilizing of nanoparticles. Moreover, all experimental results reveal new ideas for the design and optimization of multifunctional nanomaterials with higher sensitivity and pave the way for the production of new functional nanomaterials.

New degradable PCL/thiazole composite for biological applications; characterization and spectroscopic studies

Polycaprolactone (PCL) is a biodegradable polymer widely used for medical implants and devices due to its biocompatibility, processability, and tunable degradation behavior. This study explores the incorporation of a thiazole-based antimicrobial compound into PCL at varying concentrations to develop new composite materials with both biodegradability and antibacterial function. Samples were solution cast and characterized using techniques like X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, antibacterial assays, and computational density functional theory (DFT) modeling. XRD showed up to 54 % crystallinity at the highest 0.03 g dye loading, indicating the thiazole impacted ordering and lamellar packing. FTIR and DFT calculations demonstrated multiple possible intermolecular bonding modes between the compounds. UV–vis spectra revealed the superimposed absorptions of the PCL matrix and emergent thiazole chromophore. Antibacterial tests exhibited marked growth inhibition of both gram-positive and gram-negative bacteria proportional to the thiazole concentration. The customizable PCL-thiazole blends offer biocompatible materials with functional antibacterial behavior for specialized applications in biomedicine.

Sono-synthesis and characterization of next-generation antimicrobial ZnO/TiO2 and Fe3O4/TiO2 bi-nanocomposites, for antibacterial and antifungal applications

Ultrasonic-assisted synthesis of ZnO/TiO₂ and Fe₃O₄/TiO₂ bi-oxide nanocomposites at low frequencies (60 kHz) with their characterizations and antibacterial/antifungal applications are investigated in this study. Using nanotechnology as the next-generation solution, this research explored the potential of metal oxide nanoparticles as effective antibacterial agents. Nanomaterials were synthesized via a novel and facile method (sono-synthesis) and characterized using various techniques (XRD, SEM, FTIR, zeta potential analysis, Raman spectroscopy, and XPS), revealing nanoscale sizes of 25 nm for ZnO/TiO₂ and 31 nm for Fe₃O₄/TiO₂. Structural analysis demonstrated the distinct crystalline phases of the synthesized nanomaterials: TiO₂ with anatase structure (25 %), hexagonal wurtzite structure for ZnO, and Fe₃O₄ with inverse spinel structure, formed in nano-dimensions (19–31 nm) with a near-spherical shape. Antibacterial and antifungal assays highlighted the efficacy of both bi-nanocomposites against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, along with their potent activity against Candida albicans and non-albicans Candida. Moreover, principal component analysis (PCA) was used to identify potential relationships between the physicochemical properties (zeta potential, size, conductivity, and concentration) of all nanomaterials tested and their zone of inhibition (ZOI) against all bacterial species tested. Overall, this study emphasizes the novelty of employing a simple and efficient sono-synthetic route to synthesize ZnO/TiO₂ and Fe₃O₄/TiO₂ bi-nanocomposites and investigate their significant antibacterial and antifungal activities. Additionally, it identifies the potential relationships between the physicochemical properties of the nanomaterials tested and their antimicrobial activity. This approach provides a robust framework for future applications of bi-nanocomposites in combating microbial infections.

Nano-Reactors Based on Ovotransferrin Organic Skeleton through a Ferroptosis-like Strategy Efficiently Enhance Antibacterial Activity.

The issue of bacterial resistance is an escalating problem due to the misuse of antibiotics worldwide. This study introduces a new antibacterial mechanism, the ferroptosis-like death (FLD) of bacteria, and an approach to creating green antibacterial nano-reactors. This innovative method leverages natural iron-containing ovotransferrin (OVT) assembled into an organic skeleton to encapsulate low-concentration adriamycin (ADM) for synthesizing eco-friendly nano-reactors. FLD utilizes the Fenton reaction of reactive oxygen species and ferrous ions to continuously produce ·OH, which can attack the bacterial cell membrane and destroy the cell structure to achieve bacteriostasis. The OVT@ADM nano-reactors are nearly spherical, with an average diameter of 247.23 nm and uniform particle sizing. Vitro simulations showed that Fe3+ in OVT@ADM was reduced to Fe2+ by glutathione in the bacterial periplasmic space, which made the structure of OVT loose, leading to a sustained slow release of ADM from OVT@ADM. The H2O2 continuously produced by ADM oxidized Fe2+ through the Fenton reaction to produce ·OH and Fe3+. The results of the antibacterial assay showed that OVT@ADM had a satisfactory antibacterial effect against S. aureus, and the inhibition rate was as high as 99.3%. The cytotoxicity results showed that the mitigation strategy significantly reduced the cytotoxicity caused by ADM. Based on the FLD mechanism, OVT@ADM nano-reactors were evaluated and applied to bacteriostasis. Therefore, the novel antibacterial mechanism and OVT@ADM by the green synthesis method have good application prospects.

Nanocellulose/Nanoporous Silicon Composite Films as a Drug Delivery System.

Nanocellulose (NC) is a promising material for drug delivery due to its high surface area-to-volume ratio, biocompatibility, biodegradability, and versatility in various formats (nanoparticles, hydrogels, microspheres, membranes, and films). In this study, nanocellulose films were derived from "Bolaina blanca" (Guazuma crinita) and combined with nanoporous silicon microparticles (nPSi) in concentrations ranging from 0.1% to 1.0% (w/v), using polyvinyl alcohol (PVA) as a binding agent to create NC/nPSi composite films for drug delivery systems. The physicochemical properties of the samples were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The mechanical properties and drug release capabilities were also evaluated using methylene blue (MB) as an antibacterial drug model. Antibacterial assays were conducted against S. aureus and E. coli bacteria. The results show that NC/nPSi composites with 1% nPSi increased the T50% by 10 °C and enhanced mechanical properties, such as a 70% increase in the elastic modulus and a 372% increase in elongation, compared to NC films. Additionally, MB released from NC/nPSi composites effectively inhibited the growth of both bacteria. It was also observed that the diffusion coefficients were inversely proportional to the % nPSi. These findings suggest that this novel NC/nPSi-based material can serve as an effective controlled drug release system.