Search Results (239)

Background/Objectives: Tuberculosis treatment remains challenging due to the limited stability and side effects of conventional rifampicin formulations. This study aimed to synthesize and optimize mucoadhesive chitosan–gellan gum nanoparticles for improved rifampicin delivery. The novelty of this work was the introduction of ethanol into the synthesis process, which improved the solubility of rifampicin and contributed to the formation of nanoparticles with the desired physicochemical characteristics. Methods: Rifampicin-loaded chitosan–gellan gum nanoparticles were produced using the polyelectrolyte complex coacervation method. The polymer ratios, drug-to-polymer ratio, temperature and ethanol volume were the main factors that were optimized using the Taguchi method. The physicochemical properties, such as TGA, DSC and FTIR spectroscopy, were investigated. In addition, drug release, mucoadhesive properties and mycobacterial activity against the H37Rv strain of Mycobacterium tuberculosis were examined. Results: Optimization using the Taguchi method produced nanoparticles with a narrow particle distribution (PDI: 0.212 ± 0.021), a satisfactory average size (153 ± 3 nm) and stability against aggregation (zeta potential: 22.94 ± 1.30 mV). A study of the degree of rifampicin release from nanoparticles showed that the drug release is influenced by pH and has a prolonged effect. Drug-loaded nanoparticles exhibited increased mucoadhesion compared with the pure drug. The minimum inhibitory concentration of rifampicin in chitosan–gellan gum nanoparticles for the suppression of the H37RV strain of Mycobacterium tuberculosis was determined. Spectroscopic and thermal analyses confirmed the incorporation of rifampicin in the polymer matrix. Conclusions: The developed chitosan–gellan gum nanoparticles represent a promising mucoadhesive delivery system for rifampicin. The incorporation of ethanol and the use of Taguchi optimization provide an effective strategy for controlling nanoparticle properties and improving drug delivery performance. Full article

Currently, gold nanoparticles are increasingly used in targeted drug delivery nanostructures. However, their intrinsic catalytic activity is often overlooked when using them as a carrier. In this study, the interaction between the sotalol drug from the beta-blocker family and gold nanoparticles was investigated using capillary electrophoresis and high-performance liquid chromatography. Both methods showed that sotalol undergoes catalytic oxidation on the surface of citrate-stabilized gold nanoparticles into three products. Together with a cleavage of the isopropyl group from the nitrogen atom, the oxidation at the hydroxyl group occurs with the formation of a ketone. Analysis of electropherograms showed 100% conversion of sotalol after 48 h of incubation at a surface coverage of 1.2 × 10¹⁹ molecules per m². To examine the role of reactive oxygen species, the experiments were performed in oxygen-saturated and oxygen-deficient gold nanoparticle dispersions. The effects of radical scavenger additives and pH of nanoparticle dispersion were also assessed. The influence of surface ligands on sotalol conversion was studied using gold nanoparticles coated with thiols, surfactants, and polyelectrolytes. Based on comprehensive data, the mechanism of gold-nanoparticle-assisted multicenter oxidation of sotalol is proposed. Full article

Sodium alginate (SA)-modified shellac nanoparticles were developed as pH-responsive carriers for cinnamon essential oil (CEO) encapsulation in aquatic product preservation. Three polyelectrolytes (SA, chitosan (CS), gelatin (Gel)) were evaluated at concentrations of 0.025–0.3% (w/v). Under pH conditions simulating spoilage (6.0–7.5), SA-SNPs exhibited superior stability with minimal changes in particle size, PDI, and zeta potential, while CS and Gel systems aggregated near their pKa values. At 0.1% SA, CEO-loaded nanoparticles (SA-SCNPs) showed excellent properties: small size (160 nm), high encapsulation efficiency (90%), and pH-triggered release (77.76% at pH 7.0 via Ritger–Peppas kinetics, n = 0.58). FT-IR confirmed ionic and hydrogen bonding between the SA and shellac. SA-SCNPs enhanced antibacterial efficacy against Shewanella putrefaciens and Pseudomonas fluorescens and maintained stability under ionic strength (300 mmol/L NaCl) and temperature variations (−18 °C to 25 °C), attributed to SA’s cryo-resistance and steric effects. This system offers a smart delivery platform for aquatic preservation. Full article

Cutaneous wound healing is a complex biological process often impaired by bacterial infections, especially by Staphylococcus aureus. To address this, alginate (ALG)/chitosan (CS) polyelectrolyte multilayer (PEM) films incorporating alginate-coated silver nanoparticles (ALG–AgNPs) were fabricated by layer-by-layer self-assembly. The films exhibited a porous, layered morphology with homogeneous distribution of ALG–AgNPs, hydrophilic surfaces (contact angle ≈ 55°), a high swelling degree (~175%), and a water vapor transmission rate of 1830 g m⁻²·day⁻¹. Thermal analyses showed similar degradation profiles up to 600 °C, with the ALG–AgNP film displaying lower moisture loss and higher dehydration temperature, consistent with enhanced ionic and coordination crosslinking (–NH₃⁺/–COO⁻ and Ag–O–C bonds). The release of Ag⁺ in PBS (pH 7.4) was ~3% after 24 h, following a Korsmeyer–Peppas mechanism (R² = 0.97, n < 0.5), and degradation, with ~40% mass loss in 6 days, indicated gradual matrix disintegration. Cytocompatibility studies revealed >80% viability for fibroblasts, keratinocytes, macrophages, and <2% hemolysis of red blood cells. Immune assays showed a tendency towards reduced TNF-α and IL-1β and regulated IL-6/IL-8 release. Antibacterial evaluations demonstrated a 5-log reduction in planktonic bacterial viability and >2-log reduction in adhesion, and an 11 ± 1 mm inhibition zone for S. aureus. These results demonstrate that ALG/CS–AgNP PEM films combine biocompatibility, antibacterial efficacy, controlled degradation, and structural stability, making them promising multifunctional scaffolds for the regeneration of infected skin wounds. Full article

Polysaccharide-based nanocarriers offer a novel delivery system for improving the stability, controlled release, and biological functionality of plant-derived bioactive materials. Olive leaf extract (OLE), rich in polyphenolic compounds with antioxidant and other bioactive properties, is limited by low stability and bioavailability. In this study, OLE-loaded alginate–chitosan nanoparticles were prepared using ionotropic gelation–polyelectrolyte complexation (IG-PEC) method, and their physicochemical properties, cytotoxic behavior, and potential prebiotic effects were evaluated. The resulting nanoparticles (232–237 nm) exhibited uniform spherical morphology, negative zeta potentials, and improved colloidal stability. Free OLE demonstrated concentration-dependent and selective cytotoxicity toward A549 and MCF-7 cancer cells, while exhibiting lower toxicity toward normal fibroblasts. In contrast, unloaded and OLE-loaded nanoparticles (1X, 2X) showed low cytotoxicity, suggesting superior biocompatibility of the polysaccharide nanocarrier. Notably, cultures supplemented with OLE-loaded nanoparticles showed a trend toward higher probiotic growth compared to free OLE, indicating a potential prebiotic effect and improved microbial tolerance to polyphenols during extended exposure. These findings highlight the advantages of polysaccharide-based nanoencapsulation for both stabilizing bioactive materials and supporting favorable microbial responses. The developed OLE nanocarriers may serve as a promising platform for nutraceutical, biomedical, and functional food applications. Full article

Monogenean parasite infestation in fish leads to economic losses in aquaculture, representing a veterinary challenge and an environmental concern. The common administration procedures of anthelmintics to treat monogeneans in fish have low efficiency and diverse drawbacks. In this study, we produced a nanoparticle using chitosan and alginate, biodegradable and biocompatible polysaccharides, as an oral drug delivery material of albendazole anthelmintic for parasite-infected fingerlings of Nile tilapia. The molecular interaction between the biopolymers was optimized and characterized by titration calorimetry. Freeze-drying of nanoparticles resulted in a fine powder with a particle size in the order of 400 nm. The nanoparticles provided 98% encapsulation of albendazole and sustained delivery with predominantly Fickian diffusion. The palatability of the nanoparticle formulation facilitated the oral administration of albendazole. The treatment of 100% prevalence of monogeneans was effective with a six-day dosage providing a total of 915 mg/kg b.w. of drug, resulting in total parasite clearance after 10 days from the treatment beginning, evidenced by microscopy analysis, and no mortality occurred. Therefore, molecular interactions between biofriendly polyelectrolytes yielded albendazole-carrying nanoparticles for high-efficiency parasite treatment in fish farming. Full article

Alginate [ALG] and chitosan [CS] are biomaterials of importance in drug-delivery because of their ability to form ionically-crosslinked nanosystems and polyelectrolyte-complexes under mild conditions. Here, a modified ionic-polyelectrolyte-pre-gelation method, with a controlled addition of reagents and sonication throughout the process, is reported to produce ALG¬¬-CS-based NPs. A mathematical study of the effects of the factors with influence in the process on the properties of NPs has been performed using a two-phase-design-of-experiment-based procedure, something never done to our knowledge. The concentration of ALG, CS and CaCl₂ and the ratio ALG:CS have significant influence on polydispersity (PDI), surface-charge (ZP) and encapsulation efficiency (EE%) of NPs. Moreover, CS flow rate has a significant effect over PDI and EE%. Thus, the values of ALG, CS and CaCl₂ concentration (mg/mL), ALG:CS (mL:mL) and CS flow rate (mL/min) to obtain the minimum-expected PDI (0.168) or the optimized EE% (86.7) are {0.30, 0.79, 1.00, 2.50:1.00, 0.86} or {0.30, 1.00, 1.00, 2.50:1.00, 2.00}, with ALG:CaCl₂ (mL:mL) and CaCl₂ flow rate (mL/min) fixed at 2.50:0.31 and 1.25. Although most of the conditions yielded highly-negative particles (minimum-expected of −67.8 mV using 0.69, 0.30 and 0.13 mg/mL of ALG, CS and CaCl₂ and ALG:CS of 2.50:0.59 mL:mL), varying the mass ratio of ALG:CS allowed for the generation of positively-charged particles (up to +21.1 mV with 0.30, 1.00 and 0.61 mg/mL of ALG, CS and CaCl₂ and ALG:CS of 2.50:1.00 mL:mL). In both cases, ALG:CaCl₂ (mL:mL), CaCl₂ and CS flow rates (mL/min) were fixed at 2.50:0.31, 1.25 and 1.25. The model for the NPs size depends only on CS and CaCl₂ concentrations, with the minimum- or maximum-expected (160 or 635 nm) at 0.30 and 1.00 or 1.00 and 0.30 of CS and CaCl₂, although the method allows a wide range of sizes (144.0–1965.0 nm). Full article

Polyelectrolyte-based complexes have attracted attention, as the interaction of the oppositely charged components results in nanoparticle formation through an easy but highly efficient method, avoiding the use of strong solvents, extreme temperatures, and toxic chemicals. Sodium oleate (NaOL) is a widely used surfactant in the pharmaceutical industry due to its availability, eco-friendliness, and low cost. In the present study, the neutral-cationic block copolymer poly(oligo(ethylene glycol) methyl ether methacrylate)–b–quaternized poly(2-(dimethylamino) ethyl methacrylate) (POEGMA-b-Q(PDMAEMA)) is mixed with the anionic surfactant sodium oleate for the formation of nanoscale polyelectrolyte complexes through electrostatic interactions. Different weight ratios of copolymer to surfactant are studied. Then, the co-solvent protocol was implemented, and curcumin is successfully loaded in the formed particles for drug delivery applications. The size and morphology of the macromolecular complexes are examined via Dynamic Light Scattering (DLS) and Cryogenic Transmission Electron Microscopy (cryo-TEM). The methods that we have used have indicated that the polymer–surfactant complexes form spherical complexes, worm-like and vesicle-like structures. When curcumin was introduced, encapsulation was effectively achieved into micelles, giving rise to vesicle-like shapes. The success of curcumin encapsulation is confirmed by Ultraviolet–Visible absorption (UV–Vis) and fluorescence (FS) spectroscopy. POEGMA-b-Q(PDMAEMA)–sodium oleate polyelectrolyte complexes revealed promising attributes as efficient drug carrier systems for pharmaceutical formulations. Full article

Recently, interest in multifunctional materials has increased; therefore, we developed a system that combines biocompatibility, gradient changing, and antibacterial properties. We aim to combine these properties in the development of a biomimetic system based on hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, HA) by incorporating silver nanoparticles (Ag NPs) into HA matrices, leveraging their antimicrobial effects, while also exploring their role as drug-release triggers (which absorb infrared (IR) light of 808–960 nm, convert it to heat energy to induce localized heating, and cause a structural leak for drug release) to unmodified HA, which cannot be activated by IR in significant amounts. Limited diffusion aggregation is used to form HA (enhanced with glycine or produced with different outer electrolytes) by diffusing calcium phosphates through Na₂HPO₄-agar. The composite is then packed with tetracycline and a deposition of polyelectrolytes (PE). The combination of polydiallyldimethylammonium chloride (PDADMAC) and heparin forms a robust PE. Infrared light (808 nm, 1.4 mW/cm²) was utilized as energy source for non-invasive and on-demand drug release. Physical and chemical characterization of HA was carried out. Glycine did not affect the p-factor of the resulting rings, which is equal to ca. 1.00. NIR increased release rates 2.1-fold (k = 39.21 compared to 18.22). High glycine concentrations reduce HA crystallinity (94 to 30%), result in a 12.5% increased drug-loading capacity, and increase solubility (5× control). NIR reduced the Korsmeyer–Peppas release exponent (n) from 0.42 (Fickian) to 0.11 (PE-coated HA-Ag), confirming the photothermal disruption of diffusion barriers due to the presence of silver nanoparticle peaks in the composition. Full article

The thermal and optical properties of aqueous dispersions of magnetite nanoparticles were studied by dual-beam thermal-lens spectrometry. Surface-modified magnetite nanoparticles with an average crystal size of 7.5 nm were synthesized by a simple, one-stage method of coprecipitation followed by surface functionalization. For this purpose, the most popular and promising modifiers based on surfactants, polyelectrolytes, biopolymers and organic acids were used. The effect of the concentration of nanoparticles (in the range from 0.01 to 5 mg/L) and the nature of the surface modifier on the thermal diffusivity of the dispersion was studied. It was found that at concentrations of 0.4–0.6 mg/L, the dispersions exhibit heat-accumulating properties, which may be promising in the development of a magnetically controlled heat-conducting liquid. Thermal lens spectrometry in the steady-state measurement mode was used to reveal the processes of deposition and adsorption of magnetite nanoparticles on the surface of a quartz cell, leading to an apparent increase in thermal diffusivity by more than 30%. The paper touches upon the issues of accuracy and precision of temperature diffusion measurements, processing, and presentation of measurement results of time-resolved transient and steady-state signals for dispersed systems. The ratio of the change in the steady-state thermal-lens signals to the change in concentration regarding the concentration (dϑ/dc vs. c) provides a way to identify a systematic error at a low level (less than 5%) of thermal-lens measurements caused by a high concentration (or optical absorption) of the object. Various options for signal normalization (in terms of power, absorbance, and pure-solvent signal) are considered, and their advantages and disadvantages are discussed. An approach to using thermal diffusivity as a function of the steady-state signal of the sample is proposed. This approach allows for a comparative thermal-lens analysis of objects with different optical and thermal properties. Full article

Counteracting neurodegenerative diseases (NDs) presents a multifaceted challenge in the aging societies of Western countries. Each year, millions of people worldwide are affected by such ailments as Parkinson’s disease (PD), Alzheimer’s disease (AD), Huntington’s disease (HD), multiple sclerosis (MS), spinal cord injury, ischemic stroke, motor neuron disease, spinal muscular atrophy, spinocerebellar ataxia, and amyotrophic lateral sclerosis (ALS). Advancements in modern biomaterial technologies present substantial opportunities for the field of regenerative medicine. Nevertheless, limitations arise from the requirement that biomaterial design be tailored to the specific biological parameters of the target cell types with which they are intended to interact. Such an opportunity creates nanomaterials involving nanoparticles. The surface chemistry of nanoparticles, especially when functionalized with bioactive agents, enhances biocompatibility and facilitates interactions with nervous cells. Herein, we review contemporary strategies in the application of biomaterials for nerve regeneration, with particular emphasis on nanomaterials and biocompatible polyelectrolyte layers, which the authors identify as having the most significant potential to drive transformative advances in regenerative medicine in the near future. Full article

Uncontrolled hemorrhage is a major global health issue, causing high mortality rates in both civilian and military settings. The risk of infection in bleeding wounds highlights the need for effective hemostatic materials. Natural polysaccharides are promising for developing hemostatic microgels, and silver nanoparticles (AgNPs) offer antimicrobial benefits. This study aimed to synthesize a novel powdered hemostatic material using spray drying, leveraging chitosan (CHI) and carboxymethylcellulose (CMC) combined with eco-friendly AgNPs that provide antimicrobial properties. AgNPs were synthesized via a green method using CMC as a reducing and stabilizing agent, then characterized by UV-Vis, TEM, FTIR, and DLS. CHI/CMC and CHI/CMC-AgNPs microgels were created using a scalable spray drying technique and then evaluated for their morphological, physical, thermal, swelling, hemostatic, and antimicrobial properties. Characterization showed that AgNPs had monodisperse sizes and a unique UV-Vis peak at 428 nm. CHI/CMC microgels had an irregular spherical shape, with AgNPs slightly increasing their size. CHI/CMC and CHI/CMC-10AgNPs (with 10% v/v AgNPs) demonstrated appropriate swelling capacity and hemocompatibility and reduced coagulation time by 20%. However, CHI/CMC-20AgNPs (with 20% v/v AgNPs) exhibited high hemolysis. Both CHI/CMC-10AgNPs and CHI/CMC-20AgNPs displayed antimicrobial activity. In conclusion, a novel powdered hemostatic micromaterial was successfully developed, exhibiting improved properties and efficacy as a next-generation hemostatic agent. Full article

Fire retardancy and thermal management improvements in epoxy resins can critically impact their use in electronics for IoT and 5G devices. This study proposes a facile method to improve the fire retardancy and thermal properties of epoxy resins (EPs) by incorporating boron nitride nanoparticles (BNNPs) with boron polyol complex (BPC) to form an ionanofluid and explores the synergistic effect of polyelectrolytes with BN. The modified multifunctional additive BPC–BNNPs were then used for the functional modification of epoxy resin. Our detailed tests and analyses on these materials confirm that by adding 0.2 wt% of BNNPs in the EP–BPC–BN complex achieved a V-0 rating in the UL-94 vertical burning test. The resultant composite demonstrated that the modification of BN with the polyol complex imparted a low smoke and char formation in the modified epoxy composites. The current study shows that EP–BPC–BN complex has great potential as a thermal interface material for the thermal management of electronics or similar applications. The presented EP–BPC–BN composite can also be utilised as a fire-retardant coating, adhesive, and binding agent in the aerospace, transportation, and building industries. Full article

Aqueous two-phase systems (ATPSs) based on two incompatible polymers have recently garnered considerable attention due to the promising characteristics of all-aqueous emulsions for a range of applications. Recent investigations have indicated strong potential for interfacial assemblies of oppositely charged components in the stabilization of these emulsions. The formation of these confined assemblies is likely to depend on the size of the ATPS-constituting polymers; however, the role of this parameter remains to be elucidated. The primary objective of this study was to examine the effect of polyethylene oxide (PEO) molecular weight on the aging processes of PEO/dextran emulsions that are stabilized by the interfacial association of oppositely charged silica particles and polycations. It has been demonstrated that the stability of emulsions containing one high-molecular-weight dextran is significantly enhanced by increasing the size of the PEO molecules. Furthermore, a compression-induced bijel formation was observed in the ATPS with the largest molecular weight PEO sample. The observations were explained by the impact of the rheology of the aqueous phases on the aggregation, adsorption, and network formation capabilities of polycation/silica assemblies. These findings may facilitate the design of stable all-aqueous emulsions with optimal molecular weights for the ATPS-forming polymers. Full article

Electrospun alginate nanofibers are emerging as versatile materials for biomedical, environmental, and packaging applications due to their biocompatibility, biodegradability, and functional tunability. However, the direct electrospinning of alginate remains a significant challenge, mainly due to its polyelectrolytic nature, rigid chain structure, and limited chain entanglement. This review provides a comprehensive analysis of recent strategies developed to overcome these limitations, including polymer blending, chemical modification, the addition of surfactants, multi-fluid techniques, and process optimization. We systematically discuss the integration of nanofibers with functional agents such as microorganisms, bioactive compounds, plant extracts, and nanoparticles, highlighting their potential in wound healing, active packaging, bioremediation, and controlled release systems. This review also examines the scalability of alginate electrospinning, summarizing recent patents, industrial solutions, and challenges related to the standardization of the process. Key knowledge gaps are identified, including the need for long-term stability studies, structure–function correlations, green processing approaches, and expansion into novel application domains beyond healthcare. Addressing these research directions will be crucial to unlocking the full potential of alginate nanofibers as sustainable, high-performance materials for industrial use. Full article