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In this study, to improve the flame‐retardant properties of ramie fabrics (RFs), a polyelectrolyte complex (PEC) was prepared in a one‐step process using biobased guar gum (GG), polyethyleneimine (PEI), and ammonium polyphosphate (APP) and deposited on the surface of the RF to construct an intumescent flame‐retardant coating. Fabrics treated with PEC coatings exhibited excellent flame‐retardant properties. Specifically, the cone calorimeter test results revealed that an increase in sample weight of only 13.23 wt% resulted in significant reductions in the peak heat release rate (pHRR), total heat release (THR), and fire growth rate (FGR) of 91.37%, 65.12%, and 95.28%, respectively. Additionally, the limiting oxygen index (LOI) increased from 19.4% to 33.5%, and the fabrics self‐extinguished immediately after the ignition source was removed during the UL‐94 test. Scanning electron microscopy (SEM) of the char residue revealed expansion bubbles on the surface, suggesting that the PEC coating provides flame retardancy through a synergistic effect involving both the gas phase and the condensed phase. This study provides a simple and convenient solution for realizing green and efficient flame‐retardant coatings on RF. [ABSTRACT FROM AUTHOR]

Chitosan and pectin form biocompatible polyelectrolyte complex hydrogels. This study investigates the impact of cellulose nanowhiskers (CNW) and NaCl on hydrogel's properties, particularly in mechanical behavior. Swelling tests revealed deswelling under physiological conditions. Thermal analysis indicated enhanced crosslinking with CNW, correlating with mechanical, rheological, and nanoindentation findings. Hydrogels with 10% CNW exhibited higher elastic modulus in compression tests. Rheological studies showed comparable values to skin, promising for wound dressing applications. Nanoindentation highlighted CNWs' surface effect on adhesive modulus. Degradation tests over 21 days demonstrated higher degradation in NaCl-containing hydrogels. Overall, NaCl influenced polymer matrix interactions, while CNW incorporation enhanced hydrogel performance. This study distinguishes between surface and bulk properties of hydrogels, underscoring the potential of CNW in biomaterial applications. [ABSTRACT FROM AUTHOR]

In this work, three carboxymethyl starches (CMS) were obtained by the two-step reaction process of carboxymethylation with different degrees of substitution (0.16, 0.33, and 0.36). From these samples, (bio)polyelectrolyte complexes ((bio)PECs) were obtained with chitosan (Chit) by the mixing of individual solutions of polymers (0.25 wt.%) at different volume ratios. The effect of the biopolymer and ionized groups of z ratios, pH, and degree of substitution of CMS in the formation of PEC were evaluated by turbidimetry and dynamic light scattering. The results showed that increasing the amount of CMS samples (ratio of z) led to an increase in the efficiency of the formation of (bio)PEC using CMS with a high DS value. Using the turbidimetry method for the chitosan and CMS mixtures, it was observed that the formation of (bio)PEC is divided into four transition zones delimited by pH transition points, and the stoichiometric complexation (z = 1) is achieved at a pH that displayed morphological changes "pHmorph", which is a single point for Chit:CMS 1, and for Chit:CMS 2 and Chit:CMS 3, this is a range of 4.9–6.4 and 4.3–6.4, respectively. Analysis of the structural properties of the structures of (bio)PECs by dynamic light scattering was characterized by monomodal distribution, and the main observed effect was associated with an increase in the value of Davg with an increase in the ratio of Chit:CMS. [ABSTRACT FROM AUTHOR]

AbstractRecently, there has been a great interest in the development of innovative wound dressing materials based on natural bioactives, as they can accelerate the healing process and address the issues related to traditional wound dressings. The current study focuses on developing a novel derivative of guar gum (GG) and gallic acid (GA) using a simple, free radical-mediated polymerization reaction aimed at enhancing the antioxidant properties of GG. Multiple spectroscopic investigations were performed to validate the GA–GG conjugate. NMR and FTIR confirmed GA integration, UV spectroscopy indicated changes in electronic transition, DSC analysis suggested a reduction in crystallinity, and XRD revealed structural modifications. SEM revealed a porous structure that reflected its polymerized nature. Due to inadequate mechanical strength and film-forming ability of the synthesized GA–GG conjugate, polyelectrolyte complexation method using chitosan was explored to form a polyelectrolyte complex (PEC) film. The film exhibited a high swelling rate, excellent antioxidant properties, and was both hemocompatible and exhibited improved antimicrobial properties. In vitro, in ovo, and in vivo characterizations were performed to compare the performance of these biocomposite films to those of their counterparts. It promoted angiogenesis in the chick yolk sac membrane and demonstrated good cytocompatibility in cell proliferation studies on the viability of the L929 mouse fibroblast cell line. In vivo wound healing efficacy of the PEC film in wound closure was 94.5% as compared to the untreated disease control group (p < 0.001). This work highlights the development of an innovative GA–GG conjugate/chitosan PEC-based film with significant potential for wound healing applications. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Increasing demand for packaging has motivated research into sustainable materials to prevent continued plastic pollution. Materials based on polysaccharide polyelectrolyte complexes (PPCs) are emerging as a viable solution for packaging applications. We employed ball milling, a well‐established technology, for the preparation of PPC materials to create an innovative one‐step process capable of producing highly concentrated and homogeneous PPC particle precursor dispersions. We fabricated carboxymethyl cellulose (CMC) and chitosan (CS)–based PPC solutions exhibiting high‐solid loading and investigated the potential of PPC solutions made from ball milling as alternative barriers for packaging. PPC‐coated paperboard exhibited improved Cobb test performance and outstanding grease resistance as compared to pristine paper. The results certified that a single‐step process via ball milling can produce high‐solid content PPC solutions useful for creating bio‐based coatings with excellent barrier performance. [ABSTRACT FROM AUTHOR]

Artificial light harvesting, a process that involves converting sunlight into chemical potential energy, is considered to be a promising part of the overall solution to address urgent global energy challenges. Conjugated polyelectrolyte complexes (CPECs) are particularly attractive for this purpose due to their extended electronic states, tunable assembly thermodynamics, and sensitivity to their local environment. Importantly, ionically assembled complexes of conjugated polyelectrolytes can act as efficient donor-acceptor pairs for electronic energy transfer (EET). However, to be of use in material applications, we must understand how modifying the chemical structure of the CPE backbone alters the EET rate beyond spectral overlap considerations. In this report we investigate the dependence of the EET efficiency and rate on the electronic structure and excitonic wave function of the CPE backbone. To do so, we synthesized a series of alternating copolymers where the electronic states are systematically altered by introducing comonomers with electron withdrawing and electron-rich character while keeping the linear ionic charge density nearly fixed. We find evidence that the excitonic coupling may be significantly affected by the exciton delocalization radius, in accordance with analytical models based on the line-dipole approximation and quantum chemistry calculations. Our results imply that care should be taken when selecting CPE components for optimal CPEC EET. These results have implications for using CPECs as key components in water-based light-harvesting materials, either as standalone assemblies or as adsorbates on nanoparticles and thin films.

The development of nontraditional luminogens (NTLs) with enhanced and red‐shifted emissions has attracted rapidly increasing attention. Here, a new strategy is provided for preparing NTLs with enhanced and red‐shifted emissions based on polyelectrolyte complexes (PECs) formed by an anionic polyelectrolyte sodium alginate (SA) and a cationic polyelectrolyte polyethyleneimine (PEI). The direct blending of SA and PEI leads to enhanced emissions but no red‐shift in emission wavelengths in the solution and dried films. After soaking in HCl solutions (pH≤2.0), SA‐PEI PEC films are obtained. The SA‐PEI PEC wet and dried films show maximum emissions at ≈ 370 and 470 nm as well as a significantly red‐shifted emission at 550 nm. The SA‐PEI PEC dried films maintain high quantum yields under a wide range of excitation wavelengths and the quantum yield is as high as 29.4% under 470 nm excitation. Furthermore, the films emit nearly white fluorescence under the irradiation of 290 or 370 nm UV light. The enhanced and red‐shifted emission is attributed to the formation of the compact luminescent clusters with more extended through‐space conjugation and rigidified conformations through ionic bonding between NH+ groups and COO− groups and the enhanced hydrogen bonding. [ABSTRACT FROM AUTHOR]

In the realm of oil–water separation technologies, membrane-based separation emerges as an efficacious approach. Nevertheless, crafting a hydrophilic membrane capable of effectively segregating herbal volatile oil remains a formidable challenge. Our study introduces a facile in situ assembly strategy for fabricating a double-crosslinked composite coating comprising phytate (PA)-polyethyleneimine (PEI) polyelectrolyte complexes and PA-Fe3⁺ assemblies. The PA within the PA-PEI/Fe3⁺ coatings form a double cross-linking layer through interactions with amine groups and metal ions, thereby enhancing interfacial interactions and structural integrity of the membranes. Consequently, the resultant PVDF/PA-PEI/Fe3⁺ membranes exhibit improved coating stability, pronounced hydrophilicity, and exceptional antifouling capabilities, rendering them highly suitable for the separation of diverse herbal volatile oil-in-water emulsions. Furthermore, they possess the capability for reuse with an average retention ratio exceeding 90% and a pure water flux reaching up to 3200 L·m⁻2·h⁻1. Additionally, they demonstrate long-term stability and resistance to corrosion. With a simplistic yet efficient preparation process, the PVDF/PA-PEI/Fe3⁺ membrane holds significant potential for the extraction of oils from herbal volatile oil-in-water emulsions. [ABSTRACT FROM AUTHOR]

The relevance of active research lies in the need to develop new technologies to improve drug delivery methods for the effective treatment of wound healing. Additionally, the potential application of organogels in other areas of biomedicine, such as creating medical patches with controlled drug delivery, indicates a wide range of possibilities for using this technology. This study focuses on developing controlled drug delivery systems using organogels as carriers for ceftriaxone and ofloxacin. By selecting optimal formulations, organogels were created to immobilize the drugs, facilitating their effective and sustained release. The swelling behavior of the hydrogels was studied, showing a swelling coefficient between 16 and 32%, indicating their ability to absorb liquid relative to their weight. Drug release studies demonstrated that ceftriaxone was released 1.8 times slower than ofloxacin, ensuring a more controlled delivery. Microbiological tests confirmed that the organogels containing ofloxacin exhibited antimicrobial activity against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. However, it was a challenge to estimate activity for the model antibiotic ceftriaxone due to bacterial resistance to it. Organogel poly(vinyl alcohol) (PVA)-DMSO–alginate modifications with surfactant cetylpyridinium bromide led to the formation of a polyelectrolyte complex on the interphase, allowing further enhanced the prolonged release of the drugs. The research identified that the optimal compositions for sustained drug release were organogels with compositions PVA (10%)-PVP (1%) DMSO (50%) and PVA (10%)-DMSO (50%) formulations, illustrating the transparent nature of these organogels making them suitable for ophthalmological application. Various organogels compositions (PVA-DMSO, PVA-poly(vinylpyrrolidone)-DMSO, PVA-DMSO–alginate, PVA-DMSO-PLGA, PVA-DMSO–drug–surfactant) loaded with ceftriaxone, ofloxacin, and surfactant were prepared and characterized, highlighting their potential use in antibiotic patches for wound healing. These organogels illustrate promising results for localized treatment of infections in wounds, cuts, burns, and other skin lesions. [ABSTRACT FROM AUTHOR]

Dry socket, also known as alveolar osteitis, presents significant challenges in oral surgery because of severe pain and delayed wound healing. This study aims to address these challenges by developing and evaluating a lidocaine-loaded polyelectrolyte complex thermoresponsive gel (LG) designed to enhance wound healing and provide effective pain management in oral wounds. The thermoresponsive gel transitions from a liquid to a gel at body temperature, ensuring sustained contact with the wound site and prolonged release of lidocaine. The in vitro assessments, including cytotoxicity and wound scratch assays, demonstrated the biocompatibility and therapeutic potential of the LG formulation. Following this, palatal wounds were induced in rats, with healing monitored over a 14-days period. Histological analyses were conducted to assess tissue regeneration and inflammation. The results indicated that the LG formulation significantly improved wound closure rates, reduced inflammation, and accelerated epithelialization compared with control groups, primarily because of the high content of hyaluronic acid (HA). The synergistic effects of HA combined with the thermoresponsive properties of the gel facilitated faster healing. These findings suggest that LG is a promising therapeutic option for enhancing oral wound healing and effectively managing pain, particularly in conditions such as dry socket. [ABSTRACT FROM AUTHOR]

The liquid-liquid phase separation of biopolymers in living cells contains multiple interactions and occurs in a dynamic environment. Resolving the regulation mechanism is still a challenge. In this work, we designed a series of peptides (XXLY)6SSSGSS and studied their complexation and coacervation behavior with single-stranded oligonucleotides. The "X" and "Y" are varied to combine known amounts of charged and non-charged amino acids, together with the introduction of secondary structures and pH responsiveness. Results show that the electrostatic interaction, which is described as charge density, controls both the strength of complexation and the degree of chain relaxation, and thus determines the growth and size of the coacervates. The hydrophobic interaction is prominent when the charges are neutralized. Interestingly, the secondary structures of peptides exhibit profound effect on the morphology of the phases, such as solid phase to liquid phase transition. Our study gains insight into the phase separation under physiological conditions. It is also helpful to create coacervates with desirable structures and functions. [ABSTRACT FROM AUTHOR]

This study investigated the use of cellulose nanocrystals (CNC)/chitosan (Chit) polyelectrolyte complex as a stabilizing agent for Pickering emulsions. We demonstrated that chitosan reduces the surface charge of CNC improving the emulsification process. An optimal stabilizing complex containing 1% chitosan results in emulsions with minimal zeta potential (3.2 ± 0.3 mV), droplet size (2.8 ± 0.8 μm), and creaming index (19.8 ± 1.0%) values, along with high stability during storage, a change in pH, and high centrifugal forces (up to 2000 g). The study also showed that the maximum neutralized surface charge of the CNC in the CNC-Chit complex allows for effective adsorption on the surface of sunflower oil droplets, producing a denser stabilizing layer with a smaller droplet size. Additionally, chitosan addition is linked to improved stability and higher viscosity, with little dependence on ionic strength and temperature. Potentiometric titration revealed that compared with sulfated CNCs, five times less chitosan is needed to neutralize the negative surface charge of acetylated CNC. The wettability of a hydrophilic surface depends on the surface charge of the complex, and the wettability and adhesion performance increase with increasing chitosan content. Additionally, we showed that tuning the stabilizer composition can change the bioaccessibility of lipophilic compounds during oral administration. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this research, hydrogels based on chitosan, pectin, and salt (NaCl) were synthesized through the formation of polyelectrolyte complexes (PECs). The synthesis parameters, including pH, salinity, and polymer concentration, were varied to explore their influence. Weight and texture analysis revealed differences in hydrogel morphology. Swelling behavior studies showed hydrogels synthesized at pH 4 exhibiting higher swelling capacities. Additionally, the presence of salt affected the formation process. Thermal characterization showed a first decomposition step occurring around 180–224 °C. Morphological testing using SEM highlighted differences in pore size and distribution, notably when salt was included in the formulation (pore wall diameter without NaCl, 2.2 ± 1.1 um, with NaCl, 4.7 ± 1.2 um). Physico-chemical tests, including Zeta potential, FTIR, and XRD, provided insights into interactions within the hydrogels: hydrogen bonds and electrostatic interactions. Moreover, antibacterial tests demonstrated efficacy against Escherichia coli and Staphylococcus aureus, with varying inhibition degrees correlated with NaCl content (halo for E. coli without NaCl, 8 and 10 mm; with NaCl, 10 and 15 mm). Further assessments, including water vapor transmission rate (WVTR) and lidocaine release assays, highlighted hydrogel potential for wound dressing applications, with suitable moisture retention properties and controlled drug release capabilities. The release percentage achieved by the hydrogel with 0.15 M NaCl was higher than without salt (111.1% ± 9.5% and 31.16% ± 15.13%, respectively). Preliminary in vivo wound healing studies showed promising results. Overall, our findings emphasize the tunable properties of these hydrogels and their potential for wound dressings. [ABSTRACT FROM AUTHOR]

The present study aimed to fabricate innovative fibrous materials with various biological activities from poly(3-hydroxybutyrate), sodium hyaluronate (HA), chitosan (Ch), Melissa officinalis (MO), Hypericum perforatum (HP) extract, or a combination of both extracts. Electrospinning or electrospinning followed by dip coating and the subsequent formation of a polyelectrolyte complex were the methods used to prepare these materials. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR) were applied for investigating the morphology of materials, their thermal characteristics, and their surface chemical composition. The composition and design of the mats had an influence on the in vitro release behavior of the main bioactive compounds present in the MO and HP extracts incorporated in the materials. It was found that as-created materials comprising a combination of both extracts and a Ch/HA complex exerted higher antioxidant activity than that of (non-)coated MO-containing mats and Ch/HA-coated mats containing HP. The novel materials manifested antibacterial efficacy towards the pathogenic bacteria S. aureus and E. coli, as evidenced by the performed microbiological screening. Furthermore, the mats possessed a great growth inhibitory effect on HeLa cancer cells but had a less pronounced effect on the growth of normal mouse BALB/3T3 fibroblasts. The loading of both extracts in the mats and the formation of coating led to the enhancement of the in vitro anticancer and antibacterial activities of the materials. Thus, the novel materials have potential for use in local cancer therapy as well as for use as wound dressings. [ABSTRACT FROM AUTHOR]

Local anesthesia is essential in dental practices, particularly for managing pain in tooth socket wounds, yet improving drug delivery systems remains a significant challenge. This study explored the physicochemical characteristics of lidocaine hydrochloride (LH) incorporated into a polyelectrolyte complex and poloxamer thermosensitivity hydrogel, assessing its local anesthetic efficacy in mouse models and its onset and duration of action as topical anesthetics in clinical trials. The thermoresponsive hydrogel exhibited a rapid phase transition within 1–3 minutes and demonstrated pseudo-plastic flow behavior. Its release kinetics followed Korsmeyer-Peppas, with 50% of biodegradation occurring over 48 h. In mouse models, certain thermogels showed superior anesthetic effects, with rapid onset and prolonged action, as evidenced by heat tolerance in tail-flick and hot plate models. In clinical trials, the LH-loaded thermoresponsive hydrogel provided rapid numbness onset, with anesthesia (Ton) beginning at an average of 46.5 ± 22.5 seconds and lasting effectively (Teff) for 202.5 ± 41.0 seconds, ranging from 120 to 240 seconds, indicating sustained release. These results highlight the promising properties of these formulations: rapid onset, prolonged duration, mucoadhesion, biodegradability, and high anesthesia effectiveness. This study demonstrates the potential for advancing local anesthesia across various medical fields, emphasizing the synergy between material science and clinical applications to improve patient care and safety. [ABSTRACT FROM AUTHOR]

Polymer gels have shown application potential in minimizing gas channeling during CO2 enhanced oil recovery and storage processes, but the pumping pressure of preformed gels was too high, and the in‐situ cross‐linking in reservoirs was uncontrollable. Here we developed polyelectrolyte complex gels through the columbic attraction between sodium carboxymethyl cellulose (NaCMC) and protonated polyethyleneimine (PEI+) by CO2 in the presence of water. Without CO2, the viscosity of polymer complex solution is relatively low; after streaming CO2, the viscosity of the NaCMC‐PEI+ mixture aqueous solution increases significantly, forming a gel. It was also found that the complex solution shows an evolution of "sol–gel‐separated phase" as the polymer concentration increases, which could be attributed to the enhanced electrostatic attraction between CMC− and PEI+. The viscosity of the gel decreases upon increasing salinity owing to the reduced charge repulsion by the introduced inorganic salt. The CMC−‐PEI+ complex can retain its gel behavior until 60°C, after which the complex collapses. The uptake tests show that 11.34 mg CO2 can be absorbed by each gram of gel composed of 0.9 wt% NaCMC and 0.15 wt% PEI at room temperature and ambient pressure. This work provides an inexpensive route to control gas leakoff and improve CO2 absorption. [ABSTRACT FROM AUTHOR]

Herein, a novel 3D printable ink designed for the fabrication of interpenetrating polymer network (IPN) hydrogels is introduced, ingeniously integrating a polyelectrolyte complex (PEC) of hyaluronic acid (HA) and chitosan (CS) with a photo‐crosslinkable P(OEGMA‐co‐EGDEMA) polymer. Initially, the carboxyl group of HA is modified with a photo‐labile ortho‐nitrobenzyl group, preventing premature PEC formation during 3D ink formulation. Subsequent UV illumination via digital light processing (DLP) simultaneously triggers the photo‐deprotection of the carboxyl group of HA and the photopolymerization of OEGMA crosslinked hydrogel, together creating a PEC‐integrated IPN hydrogel. Comprehensive characterizations, including NMR, IR, UV/Vis, TGA, DSC, SEM, and mechanical tests are conducted to evaluate the structural, morphological, and rheological properties of these hydrogels. Furthermore, adjustments to the composition of the 3D ink enable the production of hydrogels with a spectrum of mechanical strength and elastic modulus ranging from 1 to 10 kPa. The resultant PEC‐IPN hydrogels display excellent flexibility, compressive strength, high strain tolerance, pH responsiveness, and thermal stability. In essence, the approach seamlessly merges natural polyelectrolytes with technological innovation to refine 3D ink production. This method could mark a pivotal advancement in the realm of 3D materials, unlocking numerous prospective applications. [ABSTRACT FROM AUTHOR]

Introduction: Vinorelbine tartrate is used as a first-line treatment in conjunction with conventional treatments, especially advanced disease including cancer patients. Objectives: The objective of the study was to develop a polyelectrolyte complex carrier system for Vinorelbine tartarate used for the treatment of Cancer. Materials and Methods: Polyelectrolyte Complex (PEC) was prepared using entrapment method using gum Kondagogu and chitosan as polymers. Materials and Methods: Vinorelbine tartarate was best complexed with gum Kondagogu and chitosan. Various formulations were developed by changing the gum Kondagogu and chitosan ratios and optimized. The optimized formulations were further characterized for their complex formation, loading efficiency, entrapment efficiency, particle size, FTIR studies, in vitro release, swelling studies. Results: At Gumkondagogu concentrations exceeding 80%, the highest output of PEC was noted. In comparison to phosphate buffer (pH 6.8), the PEC revealed a reduction in the discharge of vinorelbine tartarate in 0.1 N HCl. Increased medication release and swelling were caused by increasing the Kondagogu gum concentration in PEC. Due to chitosan's greater degree of swelling in an acidic medium, PEC 1:3 ("Gumkondagogu: chitosan") having a greater amount of chitosan demonstrated 98% release in just 4.5 hr. Conclusion: The observation made in the present investigation conclusively proves that the novel hydrogels prepared from gum Kondagogu/chitosan holds a great potential as a natural polymer based delivery device for controlled delivery of drug like Vinorelbine tartarate for the reason to reduce dosing frequency. [ABSTRACT FROM AUTHOR]

Polyelectrolyte complexes of chitosan (ChTS) with κ-carrageenan (CARR) have been obtained and characterized as potential adsorbents of fluorescein (FLC) nanomarker in aqueous media at different pH values. The binding of FLC to ChTS and the κ-CARR–ChTS complex has been studied by spectroscopic methods. The efficiency and mechanism of fluorone dye adsorption on the synthesized complexes have been investigated by analyzing equilibrium adsorption isotherms. The isotherm of FLC adsorption on particles of the polyelectrolyte complex has been adequately described within the framework of the Freundlich model. Data on fluorescence quenching have been used to determine the effective Stern–Volmer constants of FLC with ChTS and the κ-CARR–ChTS complex and to show that the nanomarker is bound to biopolymers via different interaction mechanisms. [ABSTRACT FROM AUTHOR]

Surface treatment is one of the most effective ways to impart flame retardancy to fabrics, woods, etc. Especially, water-soluble polyelectrolyte complex (PEC) coating deposition is one of the most environmentally benign and facile technologies. However, durability, especially washing durability, remains a challenge for almost all PEC coated materials. In an effort to keep the desirable flame retardancy of cotton despite multiple washings, in this work, perfluorodecyltrichlorosilane modified polyethylenimine (PEI) was prepared to coat onto the ammonium polyphosphate (APP) based PEC coating. The extra 2 wt% fluorinated PEI has not only retained the high LOI value (28.5%) of 10 wt% PEC-coated cotton, but also endowed this coated cotton with high water contact angle of 117°. Also, the treated cotton displayed excellent antifouling performance to milk, coffee, honey, cola and ink. Notably, it still preserved self-extinguishing behavior on a vertical flame test and high LOI value of 26.5%, after vigorously stirring in water at 40 °C for 20 times. This facile and efficient method could provide a new strategy for durable flame-retardant cotton fabric against humid and pollutant conditions. [ABSTRACT FROM AUTHOR]

Polyelectrolytes represent a unique class of polymers abundant in ionizable functional groups. In a solution, ionized polyelectrolytes can intricately bond with oppositely charged counterparts, giving rise to a fascinating phenomenon known as a polyelectrolyte complex. These complexes arise from the interaction between oppositely charged entities, such as polymers, drugs, and combinations thereof. The polyelectrolyte complexes are highly appealing in cancer management, play an indispensable role in chemotherapy, crafting biodegradable, biocompatible 3D membranes, microcapsules, and nano-sized formulations. These versatile complexes are pivotal in designing controlled and targeted release drug delivery systems. The present review emphasizes on classification of polyelectrolyte complex along with their formation mechanisms. This review comprehensively explores the applications of polyelectrolyte complex, highlighting their efficacy in targeted drug delivery strategies for combating different forms of cancer. The innovative use of polyelectrolyte complex presents a potential breakthrough in cancer therapeutics, demonstrating their role in enhancing treatment precision and effectiveness. [ABSTRACT FROM AUTHOR]

The level of environmental pollution is increasing year by year. Solving this problem requires the development and application of new effective technologies and materials for wastewater treatment and processing of accumulated waste. One of the alternative directions is membrane technologies, in particular, the development of biodegradable nanocomposite membranes. Anionic polyelectrolyte – Na-carboxymethyl cellulose with molecular weight Mw ~ 90000 and cationic polyelectrolyte – low molecular weight chitosan were used to create these membranes. Polymeric membranes were formed by mixing aqueous solutions of chitosan hydrochloride and Na-carboxymethylcellulose in different ratios. Analysis of X-ray diffractograms of polyelectrolyte complexes showed that with a gradual increase in the content of cationic polyelectrolyte from 5 % to 17 %, the structure of polyelectrolyte complexes changes dramatically. Whereas, the diffractograms of polyelectrolyte complexes with chitosan content from 29 % to 84 % are similar. The effectiveness of the obtained membranes was tested on a barometric device at different pressures. It was established that membranes based on polyelectrolyte complexes with a stoichiometric ratio of anionic and cationic polyelectrolytes turned out to be the most productive. The degree of water purification was checked by indicators of color selectivity. The obtained results allow us to conclude that with an increase in the duration of purification, the selectivity increases

Pervaporation is considered the most promising technology for dehydration of bioalcohols, attracting increasing attention as a renewable energy source. In this regard, the development of stable and effective membranes is required. In this study, highly efficient membranes for the enhanced pervaporation dehydration of ethanol were developed by modification of sodium alginate (SA) with a polyethylenimine (PEI) forming polyelectrolyte complex (PEC) and graphene oxide (GO). The effect of modifications with GO or/and PEI on the structure, physicochemical, and transport characteristics of dense membranes was studied. The formation of a PEC by ionic cross-linking and its interaction with GO led to changes in membrane structure, confirmed by spectroscopic and microscopic methods. The physicochemical properties of membranes were investigated by a thermogravimetric analysis, a differential scanning calorimetry, and measurements of contact angles. The theoretical consideration using computational methods showed favorable hydrogen bonding interactions between GO, PEI, and water, which caused improved membrane performance. To increase permeability, supported membranes without treatment and cross-linked were developed by the deposition of a thin dense layer from the optimal PEC/GO (2.5%) composite onto a developed porous substrate from polyacrylonitrile. The cross-linked supported membrane demonstrated more than two times increased permeation flux, higher selectivity (above 99.7 wt.% water in the permeate) and stability for separating diluted mixtures compared to the dense pristine SA membrane. [ABSTRACT FROM AUTHOR]

Weak bonds usually make macromolecules stronger; therefore, they are often used to enhance the mechanical strength of polymers. Not enough studies have been reported on the use of weak bonds in flame retardants. A water-soluble polyelectrolyte complex composed of polyethyleneimine (PEI), sodium tripolyphosphate (STPP) and melamine (MEL) was designed and utilized to treat bio-based polyamide 56 (PA56) by a simple three-step process. It was found that weak bonds cross-linked the three compounds to a 3D network structure with MEL on the surface of the coating under mild conditions. The thermal stability and flame retardancy of PA56 fabrics were improved by the controlled coating without losing their mechanical properties. After washing 50 times, PA56 still kept good flame retardancy. The cross-linking network structure of the flame retardant enhanced both the thermal stability and durability of the fabric. STPP acted as a catalyst for the breakage of the PA56 molecular chain, PEI facilitated the char formation and MEL released non-combustible gases. The synergistic effect of all compounds was exploited by using weak bonds. This simple method of developing structures with 3D cross-linking using weak bonds provides a new strategy for the preparation of low-cost and environmentally friendly flame retardants. [ABSTRACT FROM AUTHOR]

The soft nap and deep pile that impart comfort and warmth to cotton fleece also amplify its flammability. Using ambient aqueous processing, an environmentally benign polyelectrolyte complex (PEC), consisting of poly(allylamine hydrochloride) and sodium hexametaphosphate, was deposited on cotton fleece. This treatment adds only 12.5% weight, reduces peak heat release by 68% and total heat release by 74%, and protects from fire via intumescence. Without treatment, fleece burns aggressively with long afterburn and afterglow times, leaving no residue. With the applied PEC, the fabric self-extinguishes within a few seconds and exhibits no afterglow. In addition, it withstands at least five simulated laundering cycles in alkaline detergent, maintaining a 57% reduction in fire growth capacity afterward. The original soft surface can be restored to the fleece by manual brushing. This simple and environmentally benign treatment provides an opportunity to effectively protect highly flammable textured cellulosic textiles in a safe way. [ABSTRACT FROM AUTHOR]

Thin polymer‐based coatings with high oxygen barrier at elevated humidity are needed for the protection of food and organic electronic devices. Polyelectrolyte‐based thin films (deposited via layer‐by‐layer assembly) perform well at ambient humidity, but their performance typically dwindles as humidity increases due to their hydrophilic nature. Retention of their high barrier can be achieved through the addition of chemical crosslinkers or the introduction of inorganic platelets that create a nanobrick wall structure. In this study, a nanobrick wall barrier prepared with two types of clay, with a thickness less than 200 nm, is shown to reduce the oxygen transmission rate (OTR) of 179 µm polyethylene terephthalate to less than 0.016 cm3 m−2 day−1 atm−1. At 90% relative humidity (RH), a quadlayer barrier consisting of polyethylenimine, boehmite clay, poly(acrylic acid), and vermiculite clay maintains nearly 90% of its barrier performance at 0% RH (OTR = 0.019 cm3 m−2 day−1 atm−1). This study demonstrates the potential of dual clay thin film nanocomposites to protect various consumer goods at high humidity. [ABSTRACT FROM AUTHOR]

Engineered wood products, such as oriented strand board (OSB), are widely used as the primary structural component in both residential and commercial lumber construction, primarily due to their renewability, aesthetic appeal, and excellent mechanical properties. Unfortunately, the inherent flammability of these wood-based composites poses an ongoing risk to society and the environment. In an effort to reduce its flammability, a polyelectrolyte complex (PEC) coating consisting of sodium polyborate (SPB) and polyethylenimine (PEI) was deposited on OSB using a simple two-dip process. This PEC treatment imparts self-extinguishing behavior to OSB and reduces the total heat release by 21% and total smoke release by 79%, while increasing the time to ignition by 18% relative to untreated OSB. Furthermore, the PEI/SPB coating adds little additional weight (5.8 wt%) to the oriented strand board, preserving visual aesthetics and maintaining mechanical properties. The main flame-retardant effect occurs by condensed phase action via a combination of intumescence and thermal barrier mechanisms. Improving the fire protection of OSB and other engineered wood materials through a simple and environmentally benign treatment will increase their potential as a largely renewable building material, promoting a sustainable bioeconomy. [ABSTRACT FROM AUTHOR]

An investigation was carried out on the feasibility of obtaining a reagent based on complex compounds for regulating the parameters of a drilling mud by introducing complex‑forming ferrous cations into a sodium lignosulfonate composition followed by additional modification with phosphonic compounds and obtaining a polyelectrolyte complex derived from anionic polyelectrolyte‑sodium lignosulfonate and modified cationic starch. The presence of functional groups in the sodium lignosulfonate sample studied capable of complexation was established by IR spectrometry. The determination of the optimal ratios of the starting components for the obtaining complex compounds using lignosulfonate, iron sulfate, and phosphonic compounds was carried by mathematical modelling with the Statistica 12 software package. The surface activity of the experimental samples was studied by a stalagmometric method (drop count method). The particle size distribution method using an SALD‑7101 laser analyzer was employed to study changes in the structure of the macromolecule of sodium lignosulfonate and a polyelectrolyte complex derived from sodium lignosulfonate and cationic starch. Obtaining a stable polyelectrolyte complex by selecting the optimal ratios of the anionic and cationic components involved measuring the dependence of the impedance of an electrochemical cell on the alternating currency frequency. The best mole ratio for preparation of the polyelectrolyte complex was 1:1. Feasibility was studied for using this lignosulfonate reagent based on complex compounds as a reagent for regulating the drilling mud parameters in the temperature range from 20° to 160-180°C. [ABSTRACT FROM AUTHOR]

Crystallisation inhibitors, such as sodium ferrocyanide (NaFeCN), are highly effective in mitigating NaCl-induced weathering in lime-based mortars; however, direct addition of NaFeCN in lime-mortars increases its susceptibility to leaching and rapid depletion, thus compromising long-term performance. Here, we present hydrogel-capsules for the controlled-release of NaFeCN within hydraulic mortars for the prolonged prevention of salt weathering. Capsules were prepared by complexing chitosan and calcium-alginate in different ratios containing different concentrations of NaFeCN. The release of NaFeCN from these capsules was measured in (1) simulated lime-mortar solution (2) from mortar specimens incorporated with calcium alginate (CA) and chitosan-calcium-alginate (Cs-CA) capsules using ultraviolet–visible light spectrophotometry and Inductive Coupled Plasma-Optical Emission Spectroscopy. Mortars containing Cs-CA capsules exhibited controlled-release of NaFeCN with four times lower effective diffusion coefficient, compared to incorporating NaFeCN directly in mortar. Conversely, mortar containing CA capsules (without chitosan) released NaFeCN rapidly. Thus, chitosan’s presence in CA is necessary for tuning NaFeCN release and the reason may be attributed to chitosan’s role in reducing CA’s permeability and chitosan’s electrostatic-attraction to ferrocyanide anions, slowing diffusion of the latter. In conclusion, using Cs-CA capsules can control the release of NaFeCN within mortar, providing a steady NaFeCN supply to prolong mortar’s resistance against salt damage.

Polyelectrolyte complexes (PECs) have emerged as promising vehicles for medical applications, attributable to their non-toxicity, non-immunogenicity, and ability for controlled drug release. Notably, their inherent mucoadhesive properties are being leveraged for sustained drug delivery across mucosal barriers, including vaginal, ocular, nasal, and buccal membranes. This study delves into the formulation and effects of chitosan-(poly)acrylic acid-based PEC for vaginal tablet applications. A comparative analysis of various polymer combinations was conducted, emphasizing the differential impacts of low versus high-molecular weight chitosan. Results highlighted that PECs augmented the flowability of powder mixtures and bolstered the tablets' physical properties. Moreover, PEC-enhanced formulations exhibited a pronounced increase in swelling efficiency, with swelling index values reaching up to 92.67 % ± 1.90, ensuring structural integrity during dissolution. In ex vivo mucoadhesion tests, tablets from PEC mixes demonstrated extended adhesion, surpassing 48 h for certain formulations. The optimized PEC formulation successfully achieved sustained drug release while retaining tablet adhesion for the duration of the release period.

The relevance of active research lies in the need to develop new technologies to improve drug delivery methods for the effective treatment of wound healing. Additionally, the potential application of organogels in other areas of biomedicine, such as creating medical patches with controlled drug delivery, indicates a wide range of possibilities for using this technology. This study focuses on developing controlled drug delivery systems using organogels as carriers for ceftriaxone and ofloxacin. By selecting optimal formulations, organogels were created to immobilize the drugs, facilitating their effective and sustained release. The swelling behavior of the hydrogels was studied, showing a swelling coefficient between 16 and 32%, indicating their ability to absorb liquid relative to their weight. Drug release studies demonstrated that ceftriaxone was released 1.8 times slower than ofloxacin, ensuring a more controlled delivery. Microbiological tests confirmed that the organogels containing ofloxacin exhibited antimicrobial activity against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. However, it was a challenge to estimate activity for the model antibiotic ceftriaxone due to bacterial resistance to it. Organogel poly(vinyl alcohol) (PVA)-DMSO–alginate modifications with surfactant cetylpyridinium bromide led to the formation of a polyelectrolyte complex on the interphase, allowing further enhanced the prolonged release of the drugs. The research identified that the optimal compositions for sustained drug release were organogels with compositions PVA (10%)-PVP (1%) DMSO (50%) and PVA (10%)-DMSO (50%) formulations, illustrating the transparent nature of these organogels making them suitable for ophthalmological application. Various organogels compositions (PVA-DMSO, PVA-poly(vinylpyrrolidone)-DMSO, PVA-DMSO–alginate, PVA-DMSO-PLGA, PVA-DMSO–drug–surfactant) loaded with ceftriaxone, ofloxacin, and surfactant were prepared and characterized, highlighting their potential use in antibiotic patches for wound healing. These organogels illustrate promising results for localized treatment of infections in wounds, cuts, burns, and other skin lesions.

Dry socket, also known as alveolar osteitis, presents significant challenges in oral surgery because of severe pain and delayed wound healing. This study aims to address these challenges by developing and evaluating a lidocaine-loaded polyelectrolyte complex thermoresponsive gel (LG) designed to enhance wound healing and provide effective pain management in oral wounds. The thermoresponsive gel transitions from a liquid to a gel at body temperature, ensuring sustained contact with the wound site and prolonged release of lidocaine. The in vitro assessments, including cytotoxicity and wound scratch assays, demonstrated the biocompatibility and therapeutic potential of the LG formulation. Following this, palatal wounds were induced in rats, with healing monitored over a 14-days period. Histological analyses were conducted to assess tissue regeneration and inflammation. The results indicated that the LG formulation significantly improved wound closure rates, reduced inflammation, and accelerated epithelialization compared with control groups, primarily because of the high content of hyaluronic acid (HA). The synergistic effects of HA combined with the thermoresponsive properties of the gel facilitated faster healing. These findings suggest that LG is a promising therapeutic option for enhancing oral wound healing and effectively managing pain, particularly in conditions such as dry socket.

The inclusion of tungsten disulphide nanotubes (WS2 NTs) in chitosan, plasticized with glycerol, facilitates the formation of a polyelectrolyte complex. The glycerol interrupts the intramolecular hydrogen bonding between chitosan chains allowing positively charged protonated amines of chitosan to form a complex with negatively charged oxygen ions chemisorbed to the tungsten atoms in defects. These interactions, with the unique mechanical and chemical properties of WS2 NTs, result in a chitosan film with superior properties relative to unfilled chitosan. Even at low WS2 NT loadings (≤1 wt%), the Young's modulus (E) increases by 59%, tensile strength (σ) by 40% and tensile toughness by 74%, compared to neat chitosan, without sacrificing ductility. Addition of highly dispersed WS2 NTs significantly improves the gas barrier properties of chitosan, with a 50% reduction in oxygen permeability, while the addition of both glycerol and WS2 NTs to chitosan effectively reduces the carbon dioxide permeability by 80% and the water vapor transmission rate by 90%. The intrinsic antimicrobial efficacy of chitosan against both Gram‐positive and Gram‐negative bacteria is enhanced on inclusion of WS2 NTs. Polyelectrolyte complexation of WS2 NTs and glycerol‐plasticized chitosan provides a cost‐effective, sustainable route to biodegradable films with desirable mechanical, gas barrier properties, and antimicrobial efficacy suitable for food packaging applications. [ABSTRACT FROM AUTHOR]

Flax fabric textile is of great interest as bio‐fiber reinforcement in composites, which has gained popularity due to the high demand for sustainable materials. Despite its sustainability, flax is inherently flammable. This study demonstrates a two‐step polyelectrolyte complex (PEC) coating that renders flax fabric self‐extinguishing. The PEC coating consists of polyethylenimine (PEI) and sodium hexametaphosphate (PSP), cured with a citric acid buffer. Sonication employed during the curing process improves the infiltration of the coating into the flax fibers and maintains the fabric's hand. When comparing non‐sonicated and sonicated flax samples, the latter achieves self‐extinguishing behavior and passes the vertical flame test. Pyrolysis‐combustion flow calorimetry reveals that this PEI/PSP coating (with sonication) reduces the peak heat release rate and total heat release by 40% and 67%, respectively. The intumescent mechanism is predominantly observed in the condensed phase, as suggested by differential scanning calorimetry and X‐ray photoelectron spectroscopy. The results demonstrate that the two‐step PEC treatment with sonication effectively reduces the flammability of flax fabric, making it a promising option for the development of functional fibers, particularly for bio‐composite reinforcement. [ABSTRACT FROM AUTHOR]

Selenium nanoparticles were obtained by reduction of sodium selenite in aqueous solutions of nonstoichiometric alginate-chitosan polyelectrolyte complexes. Amorphous red nanosized selenium, formed as a result of the reaction, was characterized by a maximum absorption at 256 nm. The process of formation and morphological characteristics of the nanoparticles were studied at different mass ratios of the components in the selenium-polysaccharide complex (in the range from 0.01 to 0.10). The morphological, dimensional, and spectral characteristics of the obtained selenium nanoparticles were determined by transmission electron microscopy (TEM) and UV spectroscopy. The sample of nanoselenium was shown to consist of single nanoparticles having mostly spherical and, to a lesser extent elongated, shape, with an average size of ~40 nm. Replacement of alginate (≤10%) with chitosan caused significant increase in stability of the selenium nanoparticles, preventing their aggregation and color change for three months. The biotoxicity of the synthesized nanoselenium was studied using Aliivibrio fischeri F1 bioluminescent assay. Selenium nanosamples were found to have no any inhibitory effect on bacterial bioluminescence and growth and thus have neither acute nor chronic biotoxicity. Sodium selenite used for comparison, on the contrary, decreased the bioluminescence intensity of A. fischeri F1 at concentrations greater than 100 mg/L. The half maximal effective concentrations (EC50) of Na2SeO3 were measured to be 420–820 mg/L at 15–60 min of incubation. Chronic biotoxicity of sodium selenite was manifested at concentrations greater than 30, and 300 mg/L and higher concentrations led to complete suppression of A. fischeri F1 growth and bioluminescence. Experimental study of the biological properties of the obtained selenium nanoparticles revealed increases in the seed germination and vigor of Madonna variety of pea (Pisum sativum L.) and of Kuzen variety of barley (Hordeum vulgare L.), as well as an increase in the dry matter mass of their roots and aerial parts. A high activity of the growth processes for the studied crops was noted at a nanoselenium concentration of 20 mg/L. [ABSTRACT FROM AUTHOR]

Water-insoluble photosensitizing (PS) systems active in the generation of singlet 1O2 oxygen are obtained by immobilizing fluorinated tetraphenylporphyrin (FTPP) from a solution in acetone on films of polyelectrolyte complexes based on sodium alginate (SA) and chitosan (CT), and on solid water-insoluble gels of alginate and chitosan. The obtained polymer PS systems are used to establish the intensity of the photoluminescence of singlet oxygen in D2O and the activity of the photocatalytic oxidation of tryptophan in water. It is shown that the photocatalytic activity in the tryptophan oxidation of fluorinated tetraphenylporphyrin immobilized on a SA–CT polyelectrolyte complex and alginate solid gel is higher than that of FTPP immobilized on chitosan solid gel. Spectral-luminescent properties of polysaccharide–FTPP systems and the surface structure of carriers are studied via atomic force microscopy to determine the mechanism of the increase in porphyrin activity when it is fixed on alginate-containing carriers. It is suggested that aspects of the supramolecular structure of solid gels are responsible for the increase in the photocatalytic activity of FTPP upon immobilization on alginate-containing polysaccharide systems. [ABSTRACT FROM AUTHOR]

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Abstract The inclusion of tungsten disulphide nanotubes (WS2 NTs) in chitosan, plasticized with glycerol, facilitates the formation of a polyelectrolyte complex. The glycerol interrupts the intramolecular hydrogen bonding between chitosan chains allowing positively charged protonated amines of chitosan to form a complex with negatively charged oxygen ions chemisorbed to the tungsten atoms in defects. These interactions, with the unique mechanical and chemical properties of WS2 NTs, result in a chitosan film with superior properties relative to unfilled chitosan. Even at low WS2 NT loadings (≤1 wt%), the Young's modulus (E) increases by 59%, tensile strength (σ) by 40% and tensile toughness by 74%, compared to neat chitosan, without sacrificing ductility. Addition of highly dispersed WS2 NTs significantly improves the gas barrier properties of chitosan, with a 50% reduction in oxygen permeability, while the addition of both glycerol and WS2 NTs to chitosan effectively reduces the carbon dioxide permeability by 80% and the water vapor transmission rate by 90%. The intrinsic antimicrobial efficacy of chitosan against both Gram‐positive and Gram‐negative bacteria is enhanced on inclusion of WS2 NTs. Polyelectrolyte complexation of WS2 NTs and glycerol‐plasticized chitosan provides a cost‐effective, sustainable route to biodegradable films with desirable mechanical, gas barrier properties, and antimicrobial efficacy suitable for food packaging applications.

Worldwide, 40 to 50% of women suffer from reproductive tract infections. Most of these infections are mixed infections, are recurrent and difficult to treat with antimicrobials or antifungals alone. For symptomatic relief of infections, oral antimicrobial therapy must be combined with topical therapy. The purpose of this work is to optimize and develop a polyelectrolyte complex (PEC) of chitosan/anion for the formulation of posaconazole- and probiotic-loaded vaginal hydrogel inserts with prolonged release and significant mucoadhesion. PECs were prepared using chitosan as cationic and carrageenan, pectin and polycarbophil as anionic polymers via a lyophilization technique. PEC formation was confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry, by observing changes in its surface, physical and thermal properties. The probiotic, Lactobacillus casei, was added to the PEC during the lyophilization process and the effect on the probiotic viability was studied. The PECs were further compressed along with posaconazole to form hydrogel inserts and optimized using a 32 full-factorial design. The hydrogel inserts were assessed for swelling behavior, drug release, in vitro mucoadhesion and in vitro antifungal activity. The chitosan–pectin hydrogel insert demonstrated excellent mucoadhesion (1.25 N), sustained drug release (88.2 ± 2.4% in 8 h) and a swelling index of 154.7%. The efficacy of hydrogel inserts was evaluated using in vitro study with a co-culture of Lactobacillus casei and Candida albicans. This study revealed an increase in Lactobacilli casei count and a significant drop in the viable count of Candida albicans (4-log reduction in 24 h), indicating the effectiveness of hydrogel inserts in alleviating the fungal infection. Overall, our study demonstrated the potential of the hydrogel insert for preventing vaginal infection and restoring normal vaginal microbiota. [ABSTRACT FROM AUTHOR]

The present work had evaluated the effect of cryogenic treatment (233 K) on the degradation of polymeric biomaterial using a numerical model. The study on effect of cryogenic temperature on mechanical properties of cell-seeded biomaterials is very limited. However, no study had reported material degradation evaluation. Different structures of silk-fibroin-poly-electrolyte complex (SFPEC) scaffolds had been designed by varying hole distance and hole diameter, with reference to existing literature. The size of scaffolds were maintained at 5 × 5 mm2. Current study evaluates the effect of cryogenic temperature on mechanical properties (corelated to degradation) of scaffold. Six parameters related to scaffold degradation: heat transfer, deformation gradient, stress, strain, strain tensor, and displacement gradient were analyzed for three different cooling rates (− 5 K/min, − 2 K/min, and − 1 K/min). Scaffold degradation had been evaluated in the presence of water and four different concentrations of cryoprotectant solution. Heat distribution at various points (points_base, point_wall and point_core) on the region of interest (ROI) was found similar for different cooling rates of the system. Thermal stress was found developing proportional to cooling rate, which leads to minimal variation in thermal stress over time. Strain tensor was found gradually decreasing due to attenuating response of deformation gradient. In addition to that, dipping down of cryogenic temperature had prohibited the movement of molecules in the crystalline structure which had restricting the displacement gradient. It was found that uniform distribution of desired heat at different cooling rates has the ability to minimize the responses of other scaffold degradation parameters. It was found that the rates of change in stress, strain, and strain tensor were minimal at different concentrations of cryoprotectant. The present study had predicted the degradation behavior of PEC scaffold under cryogenic temperature on the basis of explicit mechanical properties. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a chronic autoimmune disease which affects around 1% globally leading to joint inflammation and disability. Etorocoxib (ETR) is a potent COX-2 inhibitor traditionally used orally to alleviate RA induced inflammation, yet it causes hepatic side effects on prolonged use. This study aims for in silico optimization of ETR polyelectrolyte complex (PEC) utilizing chondroitin sulphate (CS) and chitosan (CH) for transdermal delivery to RA-inflamed joints with a synergistic anti-inflammatory action owing to CS. An artificial neural network (ANN) combined with 22 factorial design was used to optimize the PEC formula according to particle size (PS) and entrapment efficiency (%EE) by varying CS and CH concentrations. The optimum ETR PEC was incorporated in a gel and examined for its in vitro release, ex vivo permeation, in vivo inflammatory biomarkers, and histopathological evaluation in rats. The optimized formula (F3) with 0.1 CH% w/w and 0.5 CS %w/w showed a PS of 214.98 ± 17.24 nm, %EE 75.31 ± 1.67%, and enhanced in vitro release profile, ex vivo permeation and in vivo anti-inflammatory effect compared to ETR gel via suppressing the expression of IL-6, TNF-α, and TGF-β pro-inflammatory cytokines as well as the additional anti-inflammatory effect of CS. In conclusion, ETR-PEC gel holds promise as transdermal therapy for managing RA-induced inflammation. [ABSTRACT FROM AUTHOR]