Search Results (441)

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

Background: Various thiolactones are known as biologically active compounds, capable of stimulating the development of several human diseases and quorum sensing of Gram–positive bacteria. The enzymatic hydrolysis of thiolactones represents a promising approach to preventing their action. Methods: Thirteen enzymes, including various lactonases and serine hydrolases were studied in this work using several substrates including the homocysteine thiolactone (HTL), and its derivatives the N–acetylhomocysteine thiolactone (C₂–HTL) and the isobutyryl–homocystein thiolactone (i–but–HTL). The potential interactions of the ligands with the surface of enzymes molecules were predicted in silico using computational modeling and checked in wet experiments in vitro. Results: Based on the data obtained several enzymes were selected with localization of the thiolactones near their active sites, indicating the possibility of effective catalysis. The lactonase (AiiA), metallo-β-lactamase (NDM-1) and the organophosphate hydrolase with hexahistidine tag (His₆–OPH) were among them. Determination of catalytic characteristics of enzymes in the hydrolytic reactions with the HTL and the C₂–HTL revealed the maximal value of catalytic efficiency constant for the NDM-1 in the hydrolysis of the HTL (826 M⁻¹ s⁻¹). The maximal activity in the hydrolysis of C₂–HTL was established for AiiA (137 M⁻¹ s⁻¹). The polyaspartic (PLD₅₀) and the polyglutamic (PLE₅₀) acids were used to obtain polyelectrolyte complexes with enzymes. The further combination of these complexes with the clotrimazole and polymyxin B possessing antimicrobial properties resulted in notable improvement of their action in relation to Staphylococcus cells. Conclusions: It was revealed that the antimicrobial activity of the polymyxin B is enhanced by 9–10 times against bacteria and yeast when combined with the His₆–OPH polyelectrolyte complexes. The antimicrobial activity of clotrimazole was increased by ~7 times against Candida tropicalis cells in the case of the AiiA/PLE₅₀/Clotrimazole combination. These results make the obtained biology attractive and promising for their further advancement to practical application. Full article

Background/Objectives: Paediatric patients continue to lack access to age-appropriate oral medicines for their treatment and have to depend on the off-label use of medicines approved for adults, which compromises dosing accuracy and exposes children to unpleasant bitterness. Building on previous proof-of-concept work with flucloxacillin sodium, this study investigated the effects of fatty-acid chain length on the formation, stability, dissolution, and sensory acceptability of diclofenac sodium (DS)–Eudragit® EPO (EE)–fatty acid (FA) polyelectrolyte complexes (PECs). Four saturated fatty acids, lauric (C12), myristic (C14), palmitic (C16), and stearic acid (C18), were evaluated at stoichiometric equimolar DS:EE:FA ratio (1:1:1). Methods: PEC microparticles were prepared by solvent evaporation. A stability-indicating RP-HPLC assay was developed and validated according to ICH guidelines to quantify DS content. Drug content and stability were monitored over 3 months at ambient storage. In vitro dissolution was performed in pH 5.5 medium at 37 °C. Taste acceptability and willingness to take again was assessed with 25 healthy adult volunteers using 11-point scale. Results: All PECs retained >90% of expected drug content after 3 months. Compared with neat DS, PECs markedly suppressed early drug release (32–39% vs. 94% at 2 min) but achieved >87% cumulative drug release in 60 min. Sensory evaluation showed significant differences across samples (p < 0.001): neat DS was least acceptable (20.8% willing to take again), while DS-EE-PA was most acceptable (92%), followed by DS-EE-SA and DS-EE-MA. DS-EE-LA was least favoured among PECs. Conclusions: Fatty-acid chain length influenced PEC formation and taste acceptability, but not the PEC stability and drug dissolution profile. Palmitic acid (DS-EE-PA) offered the best overall profile and represents a promising candidate for further development of paediatric-appropriate diclofenac formulations. Full article

The direct deposition of highly concentrated polyelectrolyte complexes based on poly(ethyleneimine) (PEI) and poly(sodium methacrylate) (PMANa) onto inorganic sand microparticles (F100 and F200) resulted in the formation of versatile core-shell composites with fast removal properties in dynamic conditions toward anionic charged pollutants. Herein, in situ-generated nonstoichiometric PEI/PMANa polyelectrolyte complexes were directly precipitated as a soft organic shell onto solid sand microparticles at a 5% mass ratio (organic/inorganic part = 5%, w/w%). The sorption of an anionic model pollutant (Indigo Carmine (IC)) onto the composite particles in dynamic conditions depended on the inorganic core size, the flow rate, the bed type (fixed or fluidized) and the initial dye concentration. The maximum sorption capacity, after 10 cycles of sorption/desorption of IC onto F100@P5% and F200@P5%, was between 16 and 18 mg IC/mL composite. The newly synthesized core-shell composites could immobilize IC at a high flow rate (8 mL/min), either from concentrated (C_IC = 60 mg/L) or very diluted (C_IC = 0.2 mg/L) IC aqueous solution, demonstrating that this type of material could be promising in water treatment or efficient in solid-phase extraction (concentration factor of 2000). Full article

A novel glucose biosensor is developed based on a tilted fiber Bragg grating (TFBG) functionalized with a pH-responsive polyelectrolyte multilayer membrane, onto which glucose oxidase (GOD) is immobilized. The sensing film is constructed via layer-by-layer self-assembly of poly(ethylenimine) (PEI) and poly(acrylic acid) (PAA), which undergoes reversible swelling and refractive index (RI) changes in response to local pH variations. These changes are transduced into measurable shifts in the resonance wavelengths of TFBG cladding modes. The catalytic action of GOD oxidizes glucose to gluconic acid, thereby modulating the interfacial pH and actuating the polyelectrolyte membrane. With an optimized (PEI/PAA)₄(PEI/GOD)₁ structure, the biosensor achieves highly sensitive glucose detection, featuring a wide measurement range (10⁻⁸ to 10⁻² M), a low detection limit of 27.7 nM, and a fast response time of ~60 s. It also demonstrates excellent specificity and robust performance in complex biological matrices such as rabbit serum and artificial urine, with recovery rates of 93–102%, highlighting its strong potential for point-of-care testing applications. This platform offers significant advantages in stability, temperature insensitivity, and miniaturization, making it well-suited for clinical glucose monitoring and disease management. Full article

Cardiac hypertrophy is a critical contributor to cardiac dysfunction and the development of heart failure, yet effective therapeutic strategies remain limited. Propylene glycol alginate sulfate sodium (PSS) is a marine sulfated polysaccharide drug used in the treatment of cardiovascular diseases and has shown cardiac function benefits. Here, we designed a pH-responsive PSS-loaded nanoparticle drug delivery system. It was self-assembled by negatively charged PSS with positively charged trimethyl chitosan glycocholic acid (TMC-GA) via electrostatic interaction, and further stabilized the nanoparticles with Hydroxypropyl methylcellulose phthalate (HP55) excipients. The prepared TMC-GA/HP55@PSS nanoparticles were spherical, with a mean particle size of 361.5 ± 1.26 nm, zeta potential of −30.3 ± 0.9 mV, and encapsulation efficiency of 92.52 ± 2.4%. In vitro release study demonstrated the pH-responsive property of TMC-GA/HP55@PSS under intestinal conditions and facilitated nanoparticles absorption in the intestinal epithelium. In vitro experiments confirmed the biocompatibility of PSS and its ability to improve myocardial cell hypertrophy. In vivo, both PSS and its nanoparticles significantly ameliorated pressure overload–induced cardiac hypertrophy in mice, with TMC-GA/HP55@PSS exhibiting better cardioprotective efficacy. This study is the first to integrate pH-responsiveness and bile acid transport-mediated uptake into PSS nanocarrier systems. The findings provide valuable data and enlightenment for designing novel formulations and expanding the clinical applications of PSS. 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

A polyelectrolyte (PE) chain in the vicinity of an oppositely charged surface can exhibit a discontinuous transition from the adsorbed to the desorbed state once the electrostatic attractive interactions are not strong enough to overcome the entropic losses caused by the PE-surface adsorption. In the context of PE–protein interactions, the heterogeneity of the charge distribution and the effects of a low dielectric permittivity underneath the surface are crucial. Studies of the combined effects of these two properties are very sparse, especially in the spherical geometry; we thus fill this gap here. We study the adsorption of PE chains onto spherical particles with heterogeneously charged surfaces, with the main focus on the critical-adsorption conditions and the effects of a low-dielectric core. Metropolis Monte Carlo simulations are employed, with the PE exploring the phase-space around the binding particle in the canonical ensemble. Two adsorption–desorption transitions are observed when the particle possesses a net charge of the same sign as that of the PE, resulting in nonmonotonic behavior of the critical charge density required for the PE–particle electrostatically driven adsorption. An increased affinity between the PEs and low-dielectric particles with variable heterogeneous charge distributions is observed, in contrast to the behavior detected for homogeneous low-dielectric particles. This higher affinity occurs when the Debye screening length in the solution becomes comparable to the dimensions of a patch of the opposite sign to the PE. A number of real-life applications of the considered PE–particle system is presented in the discussion, in particular regarding the properties of the complex formation between various PEs and globular proteins featuring a dipolar-type distribution of electric charges on their surfaces, such as insulin and bovine serum albumin. Full article

Poly(organo)phosphazenes (PPZs) are increasingly recognized as versatile biomaterials for drug delivery applications in nanomedicine. Their unique hybrid structure—featuring an inorganic backbone and highly tunable organic side chains—confers exceptional biocompatibility and adaptability. Through precise synthetic methodologies, PPZs can be engineered to exhibit a wide spectrum of functional properties, including the formation of multifunctional nanostructures tailored for specific therapeutic needs. These attributes enable PPZs to address several critical challenges associated with conventional drug delivery systems, such as poor pharmacokinetics and pharmacodynamics. By modulating solubility profiles, enhancing drug stability, enabling targeted delivery, and supporting controlled release, PPZs offer a robust platform for improving therapeutic efficacy and patient outcomes. This review explores the fundamental chemistry, biopharmaceutical characteristics, and biomedical applications of PPZs, particularly emphasizing their role in zero-dimensional nanotherapeutic systems, including various nanoparticle formulations. PPZ-based nanotherapeutics are further examined based on their drug-loading mechanisms, which include electrostatic complexation in polyelectrolytic systems, self-assembly in amphiphilic constructs, and covalent conjugation with active pharmaceutical agents. Together, these strategies underscore the potential of PPZs as a next-generation material for advanced drug delivery platforms. Full article

Protein–polyelectrolyte nanostructures assembled via electrostatic interactions offer versatile applications in biomedicine, tissue engineering, and food science. However, several open questions remain regarding their intermolecular interactions and the influence of external conditions—such as temperature and pH—on their assembly, stability, and responsiveness. This study explores the formation and stability of networks between poly(acrylic acid) (PAA) and lysozyme (LYZ) at the nanoscale upon thermal treatment, using a combination of experimental and simulation measures. Experimental techniques of static and dynamic light scattering (SLS and DLS), Fourier transform infrared spectroscopy (FTIR), and circular dichroism (CD) are combined with all-atom molecular dynamics simulations. Model systems consisting of multiple PAA and LYZ molecules explore collective assembly and complexation in aqueous solution. Experimental results indicate that electrostatic complexation occurs between PAA and LYZ at pH values below LYZ’s isoelectric point. This leads to the formation of nanoparticles (NPs) with radii ranging from 100 to 200 nm, most pronounced at a PAA/LYZ mass ratio of 0.1. These complexes disassemble at pH 12, where both LYZ and PAA are negatively charged. However, when complexes are thermally treated (TT), they remain stable, which is consistent with earlier findings. Atomistic simulations demonstrate that thermal treatment induces partially reversible structural changes, revealing key microscopic features involved in the stabilization of the formed network. Although electrostatic interactions dominate under all pH and temperature conditions, thermally induced conformational changes reorganize the binding pattern, resulting in an increased number of contacts between LYZ and PAA upon thermal treatment. The altered hydration associated with conformational rearrangements emerges as a key contributor to the stability of the thermally treated complexes, particularly under conditions of strong electrostatic repulsion at pH 12. Moreover, enhanced polymer chain associations within the network are observed, which play a crucial role in complex stabilization. These insights contribute to the rational design of protein–polyelectrolyte materials, revealing the origins of association under thermally induced structural rearrangements. Full article

Conductive hydrogels demonstrate substantial potential for flexible wearable sensors in motion monitoring, owing to their unique physicochemical properties; however, current implementations still confront persistent challenges in long-term stability, sensitivity, response speed, and detection limits under complex dynamic conditions, which material innovations are urgently required to resolve. Consequently, this paper comprehensively reviews the recent advancements in conductive hydrogel-based flexible wearable sensors for sports applications. The paper examines the conductivity, self-adhesion, self-repair, and biocompatibility of conductive hydrogels, along with detailed analyses of their working principles in resistance, capacitance, piezoelectric, and battery-based sensing mechanisms. Additionally, the paper summarizes innovative strategies to enhance sensor performance through polymer blending, polyelectrolyte doping, inorganic salt doping, and nanomaterial integration. Furthermore, the paper highlights the latest applications of conductive hydrogel flexible wearable sensors in human motion monitoring, electrophysiological signal detection, and electrochemical biosignal monitoring. Finally, the paper provides an in-depth discussion of the advantages and limitations of existing technologies, offering valuable insights and new perspectives for future research directions. Full article

Patient-specific scaffolds for tissue and organ regeneration are still limited by the difficulty of simultaneously shaping complex geometries, preserving hierarchical porosity, and guaranteeing sterility. Additive technologies represent a promising approach for addressing problems in tissue engineering, with the potential to develop personalized matrices for the growth of tissue and organ cells. The utilization of supercritical technologies, encompassing the processes of drying and sterilization within a supercritical fluid environment, has demonstrated significant opportunities for obtaining highly effective matrices for cell growth based on biocompatible materials. We present a comprehensive methodology for fabricating intricately structured, sterile aerogels based on alginate–chitosan polyelectrolyte complexes. The target three-dimensional macrostructure is achieved through (i) direct ink writing or (ii) heterophase printing, enabling the deposition of inks with diverse rheological profiles (viscosities ranging from 0.8 to 2500 Pa·s). A coupled supercritical carbon dioxide drying–sterilization regimen at 120 bar and 40 °C is employed to preserve the highly porous architecture of the printed constructs. The resulting aerogels exhibit 96 ± 2% porosity, a BET surface area of 108–238 m² g⁻¹, and complete sterility. The proposed integration of 3D printing and supercritical processing yields sterile, intricately structured aerogels with substantial potential for the fabrication of patient-specific scaffolds for tissue and organ regeneration. Full article

The low effectiveness of various brain cancer treatment methods is due to a number of significant challenges. Most of them are unable to penetrate the blood–brain barrier (BBB) when drugs are administered systemically through the bloodstream. Nanoscale particles play a special role among materials capable of binding drug molecules and successfully crossing the BBB. Biopolymeric nanoparticles (NPs) demonstrate excellent biocompatibility and have the remarkable ability to modify the environment surrounding tumor cells, thereby potentially improving cellular uptake of delivery agents. In our research, nanoscale polyelectrolyte complexes (PECs) ranging in size from 56 to 209 nm were synthesized by ionic interaction of the oppositely charged polysaccharides pectin and chitosan. The structural characteristics of these complexes were carefully characterized by infrared (FTIR) and Raman spectroscopy. The immobilization efficiency of antitumor drugs was comprehensively evaluated using UV spectrophotometry. The cytotoxicity of the NPs was evaluated in the U87-MG cell line. The preliminary data indicate a significant decrease in the metabolic activity of these tumor cells. Important details on the interaction of the NPs with an endothelial layer structurally similar to the BBB were obtained by simulating the BBB using a model based on human blood vessels. Our studies allowed us to establish a significant correlation between the kinetic parameters of drug immobilization and the ratio of biopolymer concentrations in the initial compositions, which provides valuable information for future optimization of drug delivery system design. Full article

Linear DNA constructs are used in gene delivery and therapy application due to their capacity of integration into the mammalian genome, offering stable transgene expression. Compared to circular plasmids, linear DNA also has the advantage that its dimension and steric hindrance are directly correlated to the length of the nucleotide chain. These considerations make linear DNA an effective choice for gene delivery pilot studies, where formulations and transfection efficiency calculations are studied considering the nucleic acid dimensions. Meanwhile, the development of DNA–chitosan nanoparticles (NPs) has gained significant interest for their potential in nucleic acid delivery, especially as non-viral gene delivery systems and for embedding linear DNA fragments, as well as gene delivery to the lung. This study explored an easy polyelectrolyte complexing preparation of linear DNA-loaded chitosan nanoparticles. Among the different formulations of nanoparticles prepared, the optimal one exhibited a size of approximately 290 nm, an encapsulation efficiency of 86% and a zeta potential of 25 mV. Additionally, this study examined how the concentration of DNA in solution influenced nanoparticle formation, encapsulation efficiency and particle size. In particular, transient transfection of the chitosan–linear DNA fragment complex, encoding for green fluorescent protein (GFP), was conducted in human pulmonary distal lung cells (NCI-H441 cells), demonstrating successful cellular internalization and protein expression. These studies highlight the potential of DNA–chitosan NPs in nucleic acid delivery, particularly for pulmonary applications. Future works will focus on formulating the achieved carrier into an inhalable dosage form to improve its translational application. Full article