Hydroxyethyl Cellulose Research Articles

Flexible Topical Hydrogel Patch Loaded with Antimicrobial Drug for Accelerated Wound Healing.

A hydrogel topical patch of neomycin was developed by using sodium alginate (SA) and hydroxyethylcellulose (HEC) as polymers. Free radical polymerization in an aqueous medium was initiated by using acrylic acid (AA) and N,N'-methylenebisacrylamide (MBA). Prepared hydrogels were characterized for pH sensitivity and sol-gel analysis. In addition, the effect of reactant contents on the developed formulation was evaluated by swelling behavior. SEM assay showed the rough structure of the hydrogel-based polymeric matrix, which directly enhances the ability to uptake fluid. FTIR spectra revealed the formation of a new polymeric network between reactant contents. TGA and DSC verified that fabricated polymeric patches were more thermodynamically stable than pure components. Gel fractions increased with increases in polymer, monomer, and cross-linker contents. The swelling study showed the pH-dependent swelling behavior of patches at pH 5.5, 6.5, and 7.4. The release pattern of the drug followed zero-order kinetics, with diffusion-controlled drug release patterns according to the Korsmeyer-Peppas (KP) model. Ex vivo studies across excised rabbit skin verified the drug retention in the skin layers. The hydrogel patch effectively healed the wounds produced on the rabbit skin, whereas the formulation showed no sign of irritation on intact skin. Therefore, neomycin hydrogel patches can be a potential candidate for controlled delivery for efficient wound healing.

Multifunctional cellulose-based biomaterials for dental applications: A sustainable approach to oral health and regeneration

Cellulose-based biomaterials, versatile and abundant biopolymers, present significant potential for generating sustainable, multifunctional dental materials. This work reports on recent advances in cellulose-based materials for dental applications. Their unique properties and modern processing techniques were presented. Nanocellulose, cellulose composites, carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC), and bacterial cellulose (BC) are discussed. The article provides a holistic view of these eco-friendly alternatives to traditional dental materials. Various dental applications that have benefitted from cellulose-based materials were presented, including dental restoration, bone tissue regeneration, wound dressings, dental adhesives, and dental implants. The unique characteristics of these materials enable controlled drug delivery, antibacterial activity, and bioactivity. This leads to better therapeutic outcomes and better dental health. The challenges and limitations associated with the application of cellulose-based materials in dentistry were discussed. Potential directions for future research to overcome these obstacles were provided. The significance of a multidisciplinary approach and a sustainability-focused mindset are emphasized, underscoring the potential of cellulose-based materials to drive innovation in the dental sector, especially considering sustainable environmental technologies. It resonates with the broader goal of evolving and boosting technologies toward more environmentally friendly practises through materials innovation.

Combining microfluidics and coaxial 3D-bioprinting for the manufacturing of diabetic wound healing dressings

Diabetic foot ulcers (DFUs) are a crucial complication of diabetes, as in a diabetic wound, each step of the physiological healing process is affected. This entails a more easily infectable wound, and delayed tissue regeneration due to the inflammation that occurs, leading to a drastic decrease in the overall patient's quality of life. As a strategy to manage DFUs, skin alternatives and wound dressings are currently receiving a lot of attention as they keep the wound environment “under control”, while providing bioactive compounds that help to manage infection and inflammation and promote tissue repair. This has been made possible thanks to the advent of emerging technologies such as 3D Bioprinting to produce skin resembling constructs or microfluidics (MFs) that allows the manufacture of nanoparticles (NPs) that act as drug carriers, in a prompt and less expensive way.In the present proof-of-concept study, the possibility of combining two novel and appealing techniques in the manufacturing of wound dressings has been demonstrated for first time. The novelty of this work consists in the combination of liposomes (LPs) encapsulating the active pharmaceutical ingredient (API) into a hydrogel that is further printed into a three-dimensional scaffold for wound dressing; to the knowledge of the authors this has never been done before.A grid-shaped scaffold has been produced through the coaxial 3D bioprinting technique which has allowed to combine, in one single filament, two different bioinks. The inner core of the filament is a nanocomposite hydrogel consisting of hydroxyethyl cellulose (HEC) and PEGylated LPs encapsulated with thyme oil (TO) manufactured via MFs for the first time. The outer shell of the filament, instead, is represented by a hybrid hydrogel composed of sodium alginate/cellulose nanocrystals (SA/CNC) and enriched with free TO. This provides a combination of two different release ratios of the API, a bulk release for the first 24 h thanks to the free TO in the shell of the filament and a sustained release for up to 10 days provided from the API inside the LPs. Confocal Microscopy verified the actual presence of the LPs inside the scaffold after printing and evaluation using the zone of inhibition test proved the antibacterial activity of the manufactured scaffolds against both Gram-positive and Gram-negative bacteria.

The effectiveness of obstetric gel application in shortening labor duration and preserving vaginal perineal integrity: prospective observational study

Aim: The aim of this study to determine the effects of obstetric gel application on labor outcomes.
 Materials and Method: This nonrandomized controlled study was carried out between January 2019 and June 2019 in a tertiary-care hospital. Nulliparous pregnant women with low risk, vertex position, between the ages of 16-40 years, with an estimated fetal weight of 2500-4000 grams and a gestational week between 37-41 weeks were included in the study. Using an applicator, 3-5 ml of a hydroxyethyl cellulose gel was applied to the vaginal canal of the study group (n=142) at the first stage of labor (before 5 cm cervical opening). The procedure was repeated every two hours until the birth of the baby. The control group (n=191) received standard antenatal care. 
 Results: The need for episiotomy was significantly lower in the study group compared to the control group (n=72 (50.7%) vs. n=175 (91.6%)) (Z=18.902, p

Enhancing dry mix mortar strength with natural fillers and polymers

Dry mix mortars are becoming more and more popular in the world’s building materials market. Therefore, the issue of increasing the technological and mechanical properties of stucco mixes is relevant. The aim of the paper is modification of lightweight dry stucco mixes with fine limestone and perlite as well as with hydroxyethyl methyl cellulose and dispersible polymer. In order to investigate the different mixes, an 18-point experiment was designed. Density, compressive strengths and crack resistance of dry plaster mixes were studied using requirements of standard. Mathematical models were obtained for the compositions as a result of processing the experimental data. The regularities of the fillers’ and additives’ influence on the properties of the mixes were established, depending on their amount and combination. It was observed that methyl hydroxyethyl cellulose improves the crack resistance and compression strength, and contributes to a slight decrease in density. The crack resistance of plaster mortars changes more than 1.5 times, the most crack-resistant compositions have an average amount of porous fillers.

Detailed physicochemical study and thermodynamic aspects of the interaction between nonionic cellulose derivative hydroxyethyl cellulose and anionic surfactant sodium N-dodecanoyl sarcosinate in aqueous media

BackgroundThe scheme of this work was to study the interaction between hydroxyethyl cellulose (HEC), a non-ionic, water soluble biopolymer and sodium N-dodecanoyl sarcosinate (SDDS), a novel, environmentally friendly amino acid-based anionic surfactant in aqueous medium. The study of this type of interaction is relatively less complicated compared to that between a polymer and a surfactant with opposite charges. MethodsThe critical micelle concentration (CMC) of HEC-induced SDDS has been determined by various physicochemical methods such as tensiometry, conductometry, fluorimetry and microcalorimetry. Several thermodynamic and surface parameters related to the binding of SDDS with HEC have been assessed. The aggregation number (Nagg) of SDDS micelles in the presence of non-ionic HEC polymer has been measured by the steady-state fluorescence method. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate have been measured by the dynamic light scattering method. The interaction study has further been amplified by detecting the change in the surface morphology of the polymer due to surfactant binding using Field Emission Scanning Electron Microscopy (FESEM) and high resolution transmission electron microscopy (HR-TEM) imaging in solvent-free state, as well as visualization of the HEC-SDDS micelle in the solution phase using fluorescence microscopy technique. Significant findingsFrom a physicochemical point of view, hydrophobic synergism seems to be important for understanding the interaction pattern of HEC-SDDS combination. In each scenario, the CMC of SDDS decreases with an increase in weight percentage of HEC. The aggregation number (Nagg) of SDDS micelles is also found to decrease with an increase in weight percentage of HEC in the medium. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate, these two parameters have been found to be strongly dependent on the amphiphile concentration. Finally, investigations of the surface morphologies by taking Field Emission Scanning Electron Microscopy (FESEM), high resolution transmission electron microscopy (HR-TEM) and fluorescence microscopy techniques assist the experimental data.

An evaluation of antibacterial properties and cytotoxicity of UV-curable biocompatible films containing hydroxyethyl cellulose and silver nanoparticles

The present study aimed to develop biocompatible film materials with antibacterial and anticancer properties that can be cured with UV rays depending on the thiol-en click reaction mechanism. The synthesized m-Ag NPs were added to formulations containing acrylate functionality HEC, pentaerythritol tetrarkis(3-mercaptopropionate), and photoinitiator at different rates (0, 20, 40, and 60 parts per hundred (phr)). The antibacterial activity of the films was evaluated against S. aureus, P. aeruginosa and E. coli by the disk diffusion test. The antibacterial effect of the films did not form an inhibition zone for the control formulation (Cm-Ag0 ) against bacteria whereas the antibacterial property increased as the Ag NPs content increased in formulations containing m-Ag NPs. The strongest resistance film against the three bacterial species was observed in the Cm-Ag60 formulation with 60 phr silver content, and the inhibition zones for S. aureus, P. aeruginosa, and E. coli were measured as 16.5 ± 0.7, 16.5 ± 2.1, and 16 ± 1.4, respectively. The cytotoxicity of the films against healthy cells and breast cancer cell (MCF-7) lines was investigated with MTT, and it was observed that all films did not cause any inhibition in the structure of the living cell but killed the cells at a high rate in the MCF-7 line. It was mainly observed that the Cm-Ag60 formulation showed 95.576 % cell inhibition against MCF-7. According to these results, it has been predicted that the prepared films will play a vital role in the next generation of cancer treatments.

Stabilization of low-cost phase change materials for thermal energy storage applications

Sodium sulfate decahydrate (Na2SO4.10H2O, SSD), a low-cost phase change material (PCM), can store thermal energy. However, phase separation and unstable energy storage capacity (ESC) limit its use. To address these concerns, eight polymer additives-sodium polyacrylate (SPA), carboxymethyl cellulose (CMC), Fumed silica (SiO2), potassium polyacrylate (PPA), cellulose nanofiber (CNF), hydroxyethyl cellulose (HEC), dextran sulfate sodium (DSS), and poly(sodium 4-styrenesulfonate) (PSS)-were used to explore several stabilization mechanisms. The ESC of PCMs deteriorated when thickeners, SPA, PPA, and CNF, were added. DSS-modified PCMs exhibited greater stability up to 150 cycles. Rheology measurements indicated that DSS did not impact SSD viscosity significantly during stabilization. Dynamic light scattering showed that DSS reduces SSD particle size and electrostatically suspends salt particles in a stable homogeneous solution, avoiding phase separation. This study proposes a promising method to improve the thermal stability of salt hydrate PCMs by utilizing polyelectrolyte-salt hydrate mixture for thermal energy storage applications.

FTIR, Raman spectroscopy and HT-XRD in compatibility study between naproxen and excipients

Detection of incompatibility between an active pharmaceutical ingredient (API) and excipients, including the selection of the most biopharmaceutical advantageous excipients is extremely important in the pre-formulation process of developing a solid dosage form technology. Therefore, having fast and reliable methods for identifying incompatibility is fundamental in pharmaceutical technology. For this purpose, combined Fourier transform infrared (FTIR) and Raman spectroscopy as well as high-temperature X-ray diffraction (HT-XRD) were used as a new approach for incompatibility detection, whereas differential scanning calorimetry (DSC) was applied as a reference method. In addition, to facilitate the interpretation of FTIR and Raman data, a multivariate analysis was used – hierarchical cluster analysis (HCA). The tests were carried out in mixtures of naproxen (NPX) with eight selected polymer excipients, mixed at a 1:1 ratio. The results of spectroscopic analyses have shown the physical incompatibility of NPX with methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), hydroxyethylcellulose (HEC), sodium starch glycolate (SSG) and sodium carboxymethylcellulose (CMC). HT-XRD studies performed when these mixtures were heated to 156 °C and then cooled to 25 °C showed a decrease in naproxen crystallinity in these mixtures. Furthermore, the results obtained with spectroscopic methods were confirmed by DSC tests and an intrinsic dissolution rate study.

Inserting Bi atoms on the [WO6] framework: Photochromic WO3/Bi2WO6 nanoparticles enable visual sunlight UV sensing

Photochromic tungsten oxide (WO3) offers incredible prospects for protecting human health by visually sensing ultraviolet (UV) radiation exposure from sunlight. Heterojunction engineering can improve the charge carrier separation efficiency in the photochromic procedure to implement this possibility, but it suffers from the finiteness of crystal phase interfacial contact and/or the complexity of synthetic protocols. Here, the construction of an atomic-scale crystal/amorphous WO3/Bi2WO6 nanoparticle results from introducing Bi atoms on the [WO6] framework to form [Bi2O2] components for in-situs incorporating Bi2WO6 into the WO3 matrix. The absence of well-defined interfaces in WO3/Bi2WO6 type II heterostructures ensures an efficient photoexcited electrons transfer from Bi2WO6 to WO3; abundant WO6 units serve as the sites for rapid capture and consumption of photogenerated electrons to facilitate electron-hole separation. Complexing the efficient photochromic products with hydroxyethyl cellulose, the WO3/Bi2WO6-based photochromic films (PCFs) and a colorimetric card indicating different UV intensities are developed. The invisible UV rays are converted into visible color changes; thus, the UV radiation intensity can be estimated from the dark change in the colored PCFs. This work presents a way to elevate the carrier utilization efficiency in WO3 and delivers candidates for exploring efficient and cost-effective UV radiation sensors.

Development of Polymer Membrane using Chitosan/ Hydroxyethyl Cellulose for Controlled Release of Bioactive Agent

The present work describes the fabrication of a polymer membrane using chitosan and hydroxyethyl cellulose by the solvent casting evaporation method. The membranes were loaded with curcumin which is taken as a model bioactive agent for controlled drug delivery applications. The developed membranes were characterized by different techniques such as FTIR, DSC, TGA, XRD and SEM. Curcumin-loaded membranes were tested in in vitro drug release studies in a phosphate buffer solution of pH 7.4 at 37 oC to see how quickly they swelled. The drug-encapsulated membranes have a high release rate of roughly 90% for up to 16 hours. The developed membranes follow a non-Fickian diffusion mechanism with values of ‘n’ ranging from 0.506 to 0.624. The results suggest that our developed membranes warrant further development for drug delivery applications.

Cytotoxicity and Antibacterial Efficacy of Betaine- and Choline-Substituted Polymers.

Cationic charge has been widely used to increase polymer adsorption and flocculation of dispersions or to provide antimicrobial activity. In this work, cationization of hydroxyethyl cellulose (HEC) and polyvinyl alcohol (PVA) was achieved by covalently coupling betaine hydrochloride and choline chloride to the polymer backbones through carbonyl diimidazole (CDI) activation. Two approaches for activation were investigated. CDI in excess was used to activate the polymers' hydroxyls followed by carbonate formation with choline chloride, or CDI was used to activate betaine hydrochloride, followed by ester formation with the polymers' hydroxyls. The first approach led to a more significant cross-linking of PVA, but not of HEC, and the second approach successfully formed ester bonds. Cationic, nitrogen-bearing materials with varying degrees of substitution were obtained in moderate to high yields. These materials were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, polyelectrolyte titration, and kaolin flocculation. Their dose-dependent effect on the growth of Staphylococcus aureus and Pseudomonas aeruginosa, and L929 mouse fibroblasts, was investigated. Significant differences were found between the choline- and betaine-containing polymers, and especially, the choline carbonate esters of HEC strongly inhibited the growth of S. aureus in vitro but were also cytotoxic to fibroblasts. Fibroblast cytotoxicity was also observed for betaine esters of PVA but not for those of HEC. The materials could potentially be used as antimicrobial agents for instance by coating surfaces, but more investigations into the interaction between cells and polysaccharides are necessary to clarify why and how bacterial and human cells are inhibited or killed by these derivatives, especially those containing choline.

Hydroxyethyl cellulose functionalised with maleimide groups as a new excipient with enhanced mucoadhesive properties

Hydroxyethylcellulose (HEC) is a non-ionic water-soluble polymer with poor mucoadhesive properties. The mucoadhesive properties of hydroxyethylcellulose can be improved by modifying it through conjugation with molecules containing maleimide groups. Maleimide groups interact with the thiol groups present in cysteine domains in the mucin via Michael addition reaction under physiological conditions to form a strong mucoadhesive bond. This will prolong the residence time of a dosage form containing this modified polymer and drug on mucosal surfaces. In this study HEC was modified by reaction with 4-bromophenyl maleimide in varying molar ratios and the successful synthesis was confirmed using 1H NMR and FTIR spectroscopies. The safety of the newly synthesised polymer derivatives was assessed with in vivo planaria assays and in vitro MTT assay utilising Caco-2 cell line. The synthesized maleimide-functionalised HEC solutions were sprayed onto blank tablets to develop a model dosage form. The physical properties and mucoadhesive behavior of these tablets were evaluated using a tensile test with sheep buccal mucosa. The maleimide-functionalised HEC exhibited superior mucoadhesive properties compared to unmodified HEC.

Miniature and high-performance optical fiber relative humidity sensor based on Fabry-Perot structure interacting with hydroxyethyl cellulose

A miniature Fabry-Perot fiber-optic sensor is demonstrated for high-performance relative humidity (RH) detection. This sensor is constructed by fusing a single-mode fiber to a small section of capillary coating the end with a hydroxyethyl cellulose film (HEC). The effects of capillary length and hydroxyethyl cellulose concentration on the RH response are investigated to obtain the preferential condition with capillary length of 102 μm and HEC concentration of 0.03 g/ml. A testing RH sensitivity of 1.24 nm/%RH can be achieved in the range of 48%RH to 60%RH. Simultaneously, small hysteresis errors are demonstrated in the tests with increasing and decreasing RH values. The dynamic measurements reveal a response time of 1.61 s and a recovery time of 2.1 s. The high sensitivity, good stability and simple fabrication process of the sensor make it promising for practical applications of relative humidity sensors.

An ultrafast water absorption composite cryogel containing Iron-doped bioactive glass with rapid hemostatic ability for non-compressible and coagulopathic bleeding

Traditional hemostatic materials have limited hemostatic effect on non-compressible wound, that is likely to develop into coagulopathy and leads to high mortality. As a powerful hemostatic material, in addition to having the function of forming solid physical barriers and effectively activating coagulation factors to rapidly control hemostasis, it should also has the ability to bypass the coagulation pathway to handle the bleeding of coagulopathic patients. In this work, we designed a QCOC composite cryogel by gelation of quaternized chitosan (QCS) and hydroxyethyl cellulose oxide (OHEC) at low temperature. Meanwhile, iron-doped bioactive glass (FeBG) as an active substance was introduced into the QCOC composite cryogel to promote erythrocyte aggregation by ion dissolution and activate intrinsic and extrinsic pathways. QCOC/FeBG composite cryogel had interconnected macroporous structure, ultrafast water absorption performance (reaching water absorption saturation in 4 s) and good shape memory properties (restoring to its original shape in 1 s). Additionally, the composite cryogel showed excellent antibacterial properties against S. aureus and E. coli as well as good cell biocompatibility. Furthermore, the QCOC/FeBG composite cryogel showed excellent hemostatic performance in the model of liver non-compressible hemorrhage with coagulation disorders, and the hemostasis time and blood loss were 60.87 ± 2.09 s and 366.38 ± 32.69 mg respectively, which were much lower than commercial gelatin sponge (196.62 ± 19.02 s and 1439.37 ± 165.27 mg). These results proved that QCOC/FeBG composite cryogel has excellent hemostatic properties, antibacterial properties, portability and usability, indicating a great potential as a timely hemostatic material in daily civil and military hemostasis.

Design of a novel tannic acid enriched hemostatic wound dressing based on electrospun polyamide-6/hydroxyethyl cellulose nanofibers

Recently, the use of scaffolds as wound dressings in skin tissue engineering with the aim of rapid healing and prevention of bleeding is growing quickly, materials and structures similar to the target tissue are used to improve its quality. In this research, polyamide6/hydroxyethyl cellulose (PA6/HEC) incorporated with TA (tannic acid) in different concentration (5, 10, 25%) has been used to produce nanofibers (NFs) by electrospinning method. Electrospun NFs were examined in terms of chemical and physical structure, swelling, degradation, moisture retention, thermal stability and mechanical properties. In addition, this study investigates cellular behavior, antibacterial, hemocompatibility and antioxidant properties. Among the NFs, PA/HEC/25%TA mat showed more favorable results. The produced scaffolds were non-toxic in the cell media, and increasing TA content improved cell growth and proliferation. The results of the hemostatic test showed that the presence of TA causes rapid blood coagulation, and TA has increased the antibacterial ability against pathogenic agents and antioxidant virtues. Therefore, the obtained results confirm the potential of NFs as a wound dressing.

Role of carbohydrate binding modules, CBM3A and CBM3B in stability and catalysis by a β-1,4 endoglucanase, AtGH9C-CBM3A-CBM3B from Acetivibrio thermocellus ATCC 27405

A recombinant β-1,4 endoglucanase, AtGH9C-CBM3A-CBM3B from Acetivibrio thermocellus ATCC27405 was explored for biochemical properties and the role of its associated CBMs in catalysis. The gene expressing full-length multi-modular β-1,4-endoglucanase (AtGH9C-CBM3A-CBM3B) and its truncated derivatives (AtGH9C-CBM3A, AtGH9C, CBM3A and CBM3B) were independently cloned and expressed in Escherichia coli BL21(DE3) cells and purified. AtGH9C-CBM3A-CBM3B showed maximal activity at 55 °C and pH 7.5. AtGH9C-CBM3A-CBM3B exhibited highest activity against carboxy methyl cellulose (58.8 U/mg) followed by lichenan (44.5 U/mg), β-glucan (36.2 U/mg) and hydroxy ethyl cellulose (17.9 U/mg). Catalytic module, AtGH9C showed insignificant activity against the substrates, signifying the essential requirement of CBMs in catalysis. AtGH9C-CBM3A-CBM3B displayed stability in pH range, 6.0–9.0 and thermostability up to 60 °C for 90 min with unfolding transition midpoint (Tm) of 65 °C. The generation of cellotetraose and other higher oligosaccharides by AtGH9C-CBM3A-CBM3B confirmed it as an endo-β-1,4-glucanase. AtGH9C activity was partially recovered by the addition of equimolar concentration of CBM3A, CBM3B or CBM3A + CBM3B by 47 %, 13 % or 50 %, respectively. Moreover, the associated CBMs imparted thermostability to the catalytic module, AtGH9C. These results showed that the physical association of AtGH9C with its associated CBMs and the cross-talk between CBMs are necessary for AtGH9C-CBM3A-CBM3B in effective cellulose catalysis.

Direct Ink Writing of Tubular Al<sub>2</sub>O<sub>3</sub> Membrane Support Using Agar-Based Ink in 3D-Printing

Direct ink writing was used for 3D printing of tubular Al2O3 membrane support. Agar-based ink mixtures were prepared as a paste with a proper viscoelastic behavior in achieving printing. Using agar only for mixing with Al2O3 slurry in preparing the ink mixtures showed the flow behavior resulting in failure to print the Al2O3 tube due to too low viscosity of the ink mixture—100 Pa at 40°C. However, the introduction of Hydroxyethyl cellulose (HEC) as thickener and Polyethylene glycol 1500 (PEG 1500) as lubricant helped improve the behavior of the ink mixtures to be more proper paste for printing. The amounts of HEC were varied from 0 to 2wt% of solid loading. At 2wt% HEC, the ink mixture was able to be printed highest, compared to the other ink mixtures. However, the 2wt% HEC-using ink mixtures possessed the highest sintering shrinkage at 12%, while its relative density was highest at 70%. The results indicated that it was possible to print the alumina membrane tube if its fidelity was improved further.

Delivery of soluble ethinylestradiol complex by pH‐responsive core‐shell composite hydrogel capsules

AbstractEthinylestradiol (EE) is a potent estrogen widely used to treat diseases such as breast cancer, prostate cancer, and menopausal syndrome. The poor aqueous solubility of EE leads to erratic oral absorption, resulting in suboptimal plasma levels. Developing a formulation to enhance the solubility of EE in the gastrointestinal tract would be beneficial to increase the bioavailability of EE. Thereafter, we prepare diethylenetriamine‐β‐cyclodextrin/ethinylestradiol (DETA‐β‐CD/EE) complex, aiming to increase the solubility of EE in water, and design and prepare core‐shell composite hydrogel capsules with aldocellulose and hydroxyethyl cellulose as the core and sodium alginate as the shell. The stability, swelling, drug release behavior and biocompatibility of the core‐shell hydrogel capsules are carefully investigated. And the results show that the prepared hydrogel capsules have the controlled and sustained release ability of soluble DETA‐β‐CD/EE, can achieve pH‐responding to intestinal fluid, and are non‐toxic to normal human cells.

Remediation of groundwater contaminated with trichloroethylene (TCE) using a long-lasting persulfate/biochar barrier

Groundwater contamination by chlorinated solvents causes potential threats to water resources and human health. Therefore, it is important to develop effective technologies to remediate contaminated groundwater. This study uses biodegradable hydrophilic polymers, hydroxypropyl methylcellulose (HPMC), hydroxyethyl cellulose (HEC) and polyvinyl pyrrolidone (PVP) as binders to manufacture persulfate (PS) tablets for the sustained release of persulfate to treat trichloroethylene (TCE) in groundwater. The release time for different tablets decreases in the order: HPMC (8–15 days) > HEC (7–8 days) > PVP (2–5 days). The efficiency with which persulfate is released is: HPMC (73–79%) > HEC (60–72%) > PVP (12–31%). HPMC is the optimal binder for the manufacture of persulfate tablets and persulfate is released from a tablet of HPMC/PS ratio (wt/wt) of 4/3 for 15 days at a release rate of 1127 mg/day. HPMC/PS/biochar (BC) ratios (wt/wt/wt) between 1/1/0.02 and 1/1/0.0333 are suitable for PS/BC tablets. PS/BC tablets release persulfate for 9–11 days at release rates of 1243 to 1073 mg/day. The addition of too much biochar weakens the structure of the tablets, which results in a rapid release of persulfate. TCE is oxidized by a PS tablet with an efficiency of 85% and a PS/BC tablet eliminates more TCE, with a removal efficiency of 100%, due to oxidation and adsorption during the 15 days of reaction. Oxidation is the predominant mechanism for TCE elimination by a PS/BC tablet. The adsorption of TCE by BC fits well with the pseudo-second-order kinetics and the pseudo-first-order kinetics, which describes the removal of TCE by PS and PS/BC tablets. The results of this study show that a PS/BC tablet can be used in a permeable reactive barrier for long-term passive remediation of groundwater.