Fickian Diffusion Research Articles

Novel Injectable, Self-Healing, Long-Effective Bacteriostatic, and Healed-Promoting Hydrogel Wound Dressing and Controlled Drug Delivery Mechanisms.

Multivalent ion cross-linking has been used to form hydrogels between sodium alginate (SA) and hyaluronic acid (HA) in previous studies. However, more stable and robust covalent cross-linking is rarely reported. Herein, we present a facile approach to fabricate a SA and HA hydrogel for wound dressings with injectable, good biocompatibility, and high ductility. HA was first reacted with ethylenediamine to graft an amino group. Then, it was cross-linked with oxidized SA with dialdehyde to form hydrogel networks. The dressing can effectively promote cell migration and wound healing. To increase the antibacterial property of the dressing, we successfully loaded tetracycline hydrochloride into the hydrogel as a model drug. The drug can be released slowly in the alkaline environment of chronic wounds, and the hydrogel releases drugs again in the more acidic environment with wound healing, achieving a long-term antibacterial effect. In addition, one-dimensional partial differential equations based on Fickian diffusion with time-varying diffusion coefficients and hydrogel thicknesses were used to model the entire complex drug release process and to predict drug release.

RSM optimized chitosan based composite hydrogel for sustained drug delivery applications

Hybrid hydrogels with good biocompatibility have practical applications in the field of drug delivery. However, it remains challenging to formulate the hybrid hydrogels for sustained drug release by regulating their pore size and degradation rates. Herein, a hybrid chitosan-alginate hydrogel (superabsorbent) was synthesized using maleic acid as a cross-linker and acrylamide as a grafting agent. The composite hydrogel exhibited a good swelling percentage of 1246% (at pH 10), analysed using response surface methodology (RSM). The hybrid hydrogel system was hemocompatible as well as biocompatible and utilized for drug delivery applications. Pantoprazole sodium was taken as a model drug and it was loaded in the superabsorbent using the swelling diffusion method. The composite hydrogel showed excellent encapsulation efficiency for pantoprazole sodium (99.74%). The intermolecular interactions between hydrogel and drug were examined using different analytical techniques including XRD (X-Ray Diffraction), FTIR (Fourier transform infrared), SEM (Scanning electron microscope), thermal analysis and EDX (Energy dispersive X-ray) mapping. The swelling percentage of the drug loaded hydrogel under simulated gastrointestinal conditions was recorded as 917.80% (at stomach pH 1.2) and 756.95% (at intestinal pH 7.4) where protonation/deprotonation of the drug in the hydrogel matrix played an important role. In vitro drug release from the drug-loaded hydrogel was sustained up to 10 days and correlated with its swelling tendency, displaying higher release profiles at pH 1.2 (99.69%) than at pH 7.4 (72.16%). The pore volume of hydrogel was tuned varying the cross-linker amount during synthesis. BET (Brunauer-Emmett-Teller) results revealed that the pore volume of the hydrogel varied between 0.01775–0.01327 cm3/g for the cross-linker amount between 0.18–0.26 g, respectively. The impact of various factors including amount of cross-linker, pore volume, and drug loading percentage on drug release at pH 1.2 and 7.4 was studied statistically as well as experimentally and these factors significantly controlled the drug release percentage. The drug release from the hydrogel followed the Makoid-Banakar model with Fickian diffusion mechanism. The synthesized composite chitosan-alginate hydrogel could be a promising candidate for its utilization as a sustained drug delivery system.

A chitosan-α-naphthaldehyde hydrogel film containing pineapple leaf fibers for wound dressing applications.

In recent decades, polysaccharide-based hydrogels have gained significant attention due to their natural biocompatibility, biodegradability, and non-toxicity. The potential for using polysaccharides to synthesize hydrogels is due to their ability to support cell proliferation, which is important for practical applications, particularly in the biomedical field. In this study, we have synthesized a chitosan-α-naphthal hydrogel film using a cost-effective one-step synthesis approach. The prepared hydrogel film exhibited high encapsulation efficiency for antibacterial drugs such as ciprofloxacin and lomefloxacin, with the ability to release the antibiotics in a controlled manner over an extended period and prevent long-term bacterial infections. Moreover, the Korsmeyer and Peppas power law, based on Fickian diffusion, was employed to model the entire complex drug release process and predict the drug release behavior. The hydrogel film also shows pH-induced swelling ability due to the presence of an imine bond in the hydrogel network, which is degradable at acidic pH. The incorporated therapeutic agents having antibacterial activity were effective against Gram-negative (Escherichia coli DH5α) and Gram-positive (Staphylococcus aureus subsp. aureus) bacterial strains. A wound dressing material should possess mechanical strength, but the prepared hydrogel film has low mechanical strength. To increase the mechanical strength, we have infused pineapple leaf fibers (PLFs) in the film network, resulting in a mechanical strength of 1.12 ± 0.89 MPa. In addition to its mechanical strength, significant cell viability against human embryonic kidney (HEK-293) cells was observed from in vitro cell culture experiments for this PLF-hydrogel film. As a result, the prepared therapeutic agent-loaded hydrogel film under study meets the requirements to be considered for use as a wound dressing material.

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as an insulin carrier in silk fibroin hydrogels for transdermal delivery via iontophoresis.

In this study, silk fibroin (SF) was utilized as the starting material to fabricate physically crosslinked hydrogels. Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) was synthesized and characterized as a drug carrier, with insulin as the model drug. PEDOT:PSS, with a high electrical conductivity of 1666 ± 49 S cm-1, interacted with insulin molecules via electrostatic interaction by replacing the dopant PSS molecules. Insulin-loaded PEDOT:PSS embedded in the SF hydrogel resulted in an increase in the degree of swelling, pore size, and mesh size of the hydrogel. In the in vitro release and release-permeation experiments, the amounts of insulin release and release-permeation were investigated using a modified Franz diffusion cell, under the effects of SF concentrations, electric fields, and pH values. The amounts of insulin release and release-permeation from the pristine SF hydrogel and the PEDOT:PSS/SF hydrogel followed the power laws with the scaling exponents close to 0.5, indicating the Fickian diffusion or the concentration gradient. Under electric fields, with or without PEDOT:PSS used as the drug carrier, the insulin amount and diffusion coefficient were shown to increase with the increasing electric field due to the electro-repulsive forces between the cathode and insulin molecules and SF chains, electroosmosis, and SF matrix swelling. The SF hydrogel and PEDOT:PSS as the drug carrier are demonstrated herein as new components in the transdermal delivery system for the iontophoretically controlled insulin basal release applicable to diabetes patients.

Design and Characterization of Fast-Dissolving Oral Film of Apixaban.

Following the COVID-19 pandemic, microvascular and macrovascular thrombotic problems emerged that required anticoagulants. Apixaban (RN) is a factor Xa inhibitor that treats deep vein thrombosis and the two forms of artery diseases (coronary artery disease and peripheral artery disease). The study objective was to create fast-disintegrating Apixaban Oral Thin Films (OTF) with the help of various super disintegrants to shorten disintegration time and enhance drug release in order to assist patients who have difficulty in swallowing conventional dosage forms and increase bioavailability. OTF was created using the solvent casting method. A 22 factorial design was employed in Design-Expert® software to develop an ideal formula. The optimized film formula pH, drug content, disintegration time, folding endurance, and dissolution rate were estimated, and the film was subjected to a short-term stability study. The optimized formula exhibited a cumulative drug release of 93.47% in 60 sec. The drug's in vitro release pattern shows first-order kinetics and fickian diffusion was the mechanism of drug release. These findings supported that Apixaban OTFs offer a quick release of the medication from the administration site into the systemic circulation.

Enhanced water permeation through the terahertz-induced phase and diffusion transition in metal-organic framework membranes.

Freshwater scarcity is a pressing global concern, and water desalination has emerged as a promising solution. Metal-organic framework (MOF) membranes have demonstrated exceptional potential in this regard. However, previous efforts to improve the permeability of MOFs have primarily focused on chemical modifications and synthesis rather than exploring physical methods. Using molecular dynamics simulations, we propose that the use of terahertz waves at a specific frequency of 7.5 ± 1.0 THz significantly enhances water permeability across MOF membranes, up to 27-fold, while maintaining effective ion rejection capabilities throughout the process. The mechanism behind this enhancement involves the resonance between the terahertz wave and the hydrogen bond vibrations of water within the MOF. This resonance amplifies the rotational kinetic energy of water molecules, disrupting the hydrogen bonds and causing a phase transition from quasi 1D square ice to a gas-like phase. Additionally, the diffusion behavior shifts from Fickian diffusion to sub-diffusion, resulting in improved water permeation across the MOF membrane. This study highlights the potential of terahertz waves as a physical tool to enhance the permeability of MOFs in water desalination, providing new avenues for efficient water treatment and resource sustainability.

FericipXT-coated PEGylated rutile TiO2 nanoparticles in drug delivery: in vitro assessment of imatinib release.

This study presents a facile synthesis strategy for magnetic field-responsive PEGylated iron-supplement-coated rutile titanium dioxide (TiO2) nanoparticles (NPs) for stimulus-responsive drug delivery. Imatinib, an anticancer drug, was successfully loaded into NPs, and its in vitro release was investigated under different pH conditions. XRD analysis confirmed the successful synthesis of PEGylated iron supplement-coated rutile titania NPs. HR-TEM studies revealed an increased NP size due to the coating, PEGylation, and drug loading, which was corroborated by FTIR spectra, confirming the drug loading into the NPs. DLS provided a hydrodynamic diameter of 642.2 nm and polydispersity index of 0.277 for PEGylated NPs, indicating their enhanced biodistribution and narrow size distribution. PEGylated NPs exhibited a negative zeta potential of -32.89 mV, indicating high stability. In vitro drug-release studies demonstrated controlled release with maximum efficiency under acidic conditions. Hemolysis assay confirmed the safety and biocompatibility of PEGylated NPs. All drug-loaded nanoformulations followed the Peppas-Sahlin model, suggesting Fickian diffusion and Case II relaxation mechanism of drug release. These NPs have the potential for the targeted delivery and controlled release of chemotherapeutics, thereby minimizing side effects.

Mathematical modeling of vancomycin release from Poly-L-Lactic Acid-Coated implants.

This study aimed to develop a mathematical model to predict the release profile and antibacterial efficacy of a vancomycin delivery system integrated with poly(L-lactic acid)-coated bone implants specifically designed for bone plates. Using Fickian diffusion principles within an ANSYS-CFX computational fluid dynamic model, we validated the model against our in vitro vancomycin release and agar diffusion studies, as well as previously published in vivo data, confirming the reliability of the model. The model predictions demonstrated the effectiveness of the system in inhibiting bacterial growth in surrounding tissue with no observed toxicity, with a peak vancomycin concentration of 0.95 mg/ml at 6 hours, followed by a decrease to levels that remained effective for antibacterial activity. Furthermore, a sensitivity analysis revealed that the model is particularly sensitive to the half-life of vancomycin, with a maximum sensitivity index of 0.8, indicating its greater impact on the prediction accuracy than the diffusion coefficient, which has a maximum sensitivity index of 0.5. Therefore, precise input of vancomycin's half-life is critical for accurate predictions. These findings offer substantial support for the efficacy of the local delivery system as a promising therapeutic approach against implant-associated infections.

Modeling of Release Mechanism of Sage (Salvia fruticosa Miller) Phenolics Encapsulated in Alginate Capsule: Physicochemical Properties

Alginate capsules are promising delivery systems for encapsulation and release of phenolics since they can be fabricated from food‐grade biopolymers using mild processes. On the other hand, knowing the release kinetic of the phenolic in the capsules is critical for capsule fabrication and product quality improvement This study is aimed at mathematically modeling the transfer of encapsulated sage (Salvia fruticosa Miller) phenolics in alginate particles to water and to determine some physicochemical properties of capsules containing different concentrations of phenolics. The water activity values (aw) of the capsule varied between 0.9976 and 0.9990. Sphericity factors of 1 (37.5 ppm), 2 (75 ppm), 3 (150 ppm), 4 (300 ppm), and control (0 ppm) samples were determined as 0.042, 0.044, 0.043, 0.273, and 0.039, respectively. The yellowness (+b ∗) value of the samples increased significantly as the added sage extract concentration increased. While the phenolic content of the samples was determined between 0.174 and 1.1831 mg/kg GAE, the antioxidant activity values were determined between 0.9602 and 6.6930. To understand the mechanism of phenolic release from the capsules, six different mathematical models were used (First Order, Higuchi, Korsmeyer-Peppas, Hixson and Crowell, The Peppas-Sahlin, and Gompertz). The highest R2 (0.9952‐0.9979) and the lowest RMSE (1.0171‐1.7032) values were calculated in The Peppas‐Sahlin among the six models. The Peppas‐Sahlin model kinetic parameters indicated the dominance of Fickian diffusion and the minor effect of relaxation process in the mechanism of phenolic release.

Controlled delivery of 5-fluorouracil from monodisperse chitosan microspheres prepared by emulsion crosslinking.

This work aims to determine the optimal conditions for emulsion cross-linking of chitosan (CHS) with various molecular weights using glutaraldehyde as a cross-linking agent to produce 5-fluorouracil-loaded CHS microspheres (5-FU/CHS). Their drug loading and encapsulation efficiencies are found to be in the range of 3.87-12.35% and 20.13-70.45%, respectively. The dynamic light scattering results show that 5-FU/CHS microspheres are micron-sized with a uniform size distribution, and the scanning electron microscopy results show that they are spherical. The results of thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy demonstrate that 5-FU is successfully incorporated into the microspheres. The in vitro release tests show that 5-FU/CHS have a prolonged, pH-responsive release pattern of 5-FU, and the cumulative release rate under acidic condition is much larger than that under neutral conditions. The drug release kinetic analysis further demonstrates that the release of 5-FU can be well described by the Fickian diffusion model.

All-atom molecular dynamics simulation of solvent diffusion in an unentangled polystyrene film.

The diffusion behavior of low molecular weight solvents within an unentangled polystyrene film below and above its glass transition temperature is investigated. The diffusion behavior in the glassy state exhibits a distinct behavior known as case II or class II diffusion, noticeably diverging from conventional Fickian diffusion observed above the glass transition temperature of the polymer film. In the context of case II diffusion, the primary experimental observation entails the emergence of a well-defined concentration front moving at a constant speed, delineating a swollen, rubbery region from a glassy region within the polymer system. Despite the prevalence of this phenomenon in experimental settings, simulating case II diffusion has posed a significant challenge, primarily due to the computationally intensive nature of the diffusion process. To address this, we have developed an all-atom molecular dynamics simulation approach for the observation of case II diffusion in glassy polymers. This method aims to unravel the intricacies of the diffusion process, providing valuable insights into the dynamic interactions between solvents and the polymer matrix.

Thermosensitive Chitosan Hydrogels: A Potential Strategy for Prolonged Iron Dextran Parenteral Supplementation.

Iron deficiency anemia (IDA) presents a global health challenge, impacting crucial development stages in humans and other mammals. Pigs, having physiological and metabolic similarities with humans, are a valuable model for studying and preventing anemia. Commonly, a commercial iron dextran formulation (CIDF) with iron dextran particles (IDPs) is intramuscularly administered for IDA prevention in pigs, yet its rapid metabolism limits preventive efficacy. This study aimed to develop and evaluate chitosan thermosensitive hydrogels (CTHs) as a novel parenteral iron supplementation strategy, promoting IDPs' prolonged release and mitigating their rapid metabolism. These CTHs, loaded with IDPs (0.1, 0.2, and 0.4 g of theoretical iron/g of chitosan), were characterized for IM iron supplementation. Exhibiting thermosensitivity, these formulations facilitated IM injection at ~4 °C, and its significant increasing viscosity at 25-37 °C physically entrapped the IDPs within the chitosan's hydrophobic gel without chemical bonding. In vitro studies showed CIDF released all the iron in 6 h, while CTH0.4 had a 40% release in 72 h, mainly through Fickian diffusion. The controlled release of CTHs was attributed to the physical entrapment of IDPs within the CTHs' gel, which acts as a diffusion barrier. CTHs would be an effective hydrogel prototype for prolonged-release parenteral iron supplementation.

A pH-Responsive Psyllium-Hyaluronic acid and Collagen based Hydrogel for Oral Insulin Delivery

Diabetes mellitus is a chronic and heritable condition which grows adverse with date and eventually accelerates numerous difficulties such as end-stage renal disease, cardiac infections and vision problems. Objective: To highlight protein-based hydrogels as a contemporary focus in insulin delivery through the oral cavity. Methods: Novel hydrogels were formed in this study by using biomaterials (Psyllium, Hyaluronic acid and Collagen). The hydrogels were synthesized through a methodical process involving the combination of psyllium ispaghol husk, hyaluronic acid, and collagen for targeted insulin delivery. Initially, 1g of psyllium ispaghol husk was uniformly mixed with 200ml of distilled water. After achieving a homogeneous swelling, hyaluronic acid and collagen were added to the mixture. The synthesis of hydrogels was achieved by allowing the mixture to incubate at 38°C O/N. Physical characterization was done using FTIR analysis which indicates different bonding patterns. Results: Swelling ratio and drugs kinetics of hydrogels reveal maximum swelling and drug release at alkaline pH while minimum at acidic pH. Swelling kinetics shows that hydrogels followed less Fickian diffusion. These points favour the delivery of insulin in the intestine while escaping the acidic medium of stomach. Zone of inhibition around the hydrogels illustrated its antimicrobial activity. Finally, its administration to mice indicates the delivery of insulin by the decrease in glucose level measured by glucometer. Conclusions: Based on the diverse analyses conducted, it can be inferred that utilizing biomaterial-based hydrogels holds significant promise for effective insulin delivery through the oral route, especially beneficial for diabetic patients.

Targeted co-delivery of FOXM1 aptamer and DOX by nucleolin aptamer-functionalized pH-responsive biocompatible nanodelivery system to enhance therapeutic efficacy against breast cancer: in vitro and in vivo.

Targeted nanodelivery systems offer a promising approach to cancer treatment, including the most common cancer in women, breast cancer. In this study, a targeted, pH-responsive, and biocompatible nanodelivery system based on nucleolin aptamer-functionalized biogenic titanium dioxide nanoparticles (TNP) was developed for targeted co-delivery of FOXM1 aptamer and doxorubicin (DOX) to improve breast cancer therapy. The developed targeted nanodelivery system exhibited almost spherical morphology with 124.89 ± 12.97 nm in diameter and zeta potential value of - 23.78 ± 3.66 mV. FOXM1 aptamer and DOX were loaded into the nanodelivery system with an efficiency of 100% and 97%, respectively. Moreover, the targeted nanodelivery system demonstrated excellent stability in serum and a pH-responsive sustained drug release profile over a period of 240 h following Higuchi kinetic and Fickian diffusion mechanism. The in vitro cytotoxicity experiments demonstrated that the targeted nanodelivery system provided selective internalization and strong growth inhibition effects of about 45 and 51% against nucleolin-positive 4T1 and MCF-7 breast cancer cell lines. It is noteworthy that these phenomena were not observed in nucleolin-negative cells (CHO). The preclinical studies revealed that a single-dose intravenous injection of the targeted nanodelivery system into 4T1-bearing mice inhibited tumor growth by 1.7- and 1.4-fold more efficiently than the free drug and the non-targeted nanodelivery system, respectively. Our results suggested that the developed innovative targeted pH-responsive biocompatible nanodelivery system could serve as a prospectively potential platform to improve breast cancer treatment.

Solid Dispersions: An Effective Technology for Improving Dissolution Kinetics of Poorly Soluble Drugs

Solid dispersions are one of the essential technologies for improving solubility and dissolution kinetics of drugs. They can be prepared in several ways and using different carriers. This technique is very suitable for class II BCS drugs, one of which is mefenamic acid. This paper is devoted to improving the solubility and dissolution rate of mefenamic acid by preparing solid dispersions using polyethylene glycol 4000, polyvinylpyrrolidone K30, and polysorbate 80 as carriers. Solid dispersions were prepared by kneading method, and dissolution was studied for two hours in phosphate buffer (pH=8). Experimental data of drug release from prepared solid dispersions were analysed according to different mathematical models. The results showed that the dissolution rate varied depending on the type and fraction of the carrier. However, mefenamic acid was released from all prepared formulations in accordance with the Higuchi model, and the release mechanism was better described by Fickian diffusion.

Water in Epoxy Coatings: Basic Principles of Interaction with Polymer Matrix and the Influence on Coating Life Cycle

This review describes the interaction of epoxy coatings with water, the kinetics of water uptake in epoxy resins, and the methods of studying the latter (gravimetric, IR (Infrared) and NMR (Nuclear magnetic resonance) spectroscopies). The analysis of experimental data requires using mathematical models which simulate the processes that occur during water uptake in a polymer matrix. This review classifies the numerous models applied for the study of water absorption into two large groups: Fickian and non-Fickian models. Fickian models involve the Fickian diffusion model and its development for the case of anomalous diffusion, as well as the models of Jacobs–Jones, Berens–Hopfenberg, and the time-varying diffusion coefficient model. The Carter–Kibler approach is provided as an example of a non-Fickian or Langmuir-type model. A critical analysis of the experimental methods is provided, including advantages and possible experimental errors. The methods used for processing experimental data are discussed as well as the effect of water on the exploitation properties and life cycle of epoxy coatings.

PH-responsive chitosan/poly (vinyl pyrrolidone) based hydrogel composites: Antibacterial properties and release kinetics of diclofenac sodium

Development of effective hydrogels based anti-inflammatory drug delivery materials remains great challenge. In this study, diclofenac sodium (DS) was successfully encapsulated into chitosan (CS)/poly (vinyl pyrrolidone) (PVP) with glutaraldehyde crosslinked hydrogels. The characteristics of the hydrogel composites were characterized by swelling behavior, FTIR spectroscopy, hydrophilicity, and porosity test, SEM-EDX, X-ray diffraction, thermal stability, and mechanical strength methods. pH-dependent drug (DS) release behavior and the antibacterial activity of the hydrogel composites were examined. Typically, the interaction of polymer precursors, crosslinker, and drug compound occurred via hydrogen bonding. The cross-sectional SEM images demonstrated the pore formation in hydrogel matrix. Mechanical properties of hydrogel improved from 8.9 to 13.1 MPa due to crosslinking process and DS encapsulation. Insertion of diclofenac sodium improved the hydrophilicity as shown in the lowering of contact angle to 55.47°. Hydrogel samples showed promising antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus with the zone of inhibition (ZoI) up to 21.8 ± 0.05 mm and 18.7 ± 0.09 mm, respectively. The controlled DS release from hydrogel composites at pH 4, 7 and 10 has maximum release amount of approximately around 10 %, 80 %, and 90 %, respectively. The kinetics and mechanism of drug release from hydrogels was followed Kosmeyer-Peppas and Higuchi models, indicating that the DS release from hydrogel was predominantly controlled by Fickian diffusion or swelling process. These results indicated that the pH-responsive hydrogels based on CS/PVP can be a promising candidate for drug delivery due to its high susceptibility to antibacterial activity.

Formulation Development of Mucoadhesive Tablets for Treatment of Hypertension using Losartan Potassium

Controlled-release losartan potassium incorporated bucccoadhesive tablets were prepared using guar gum and hydroxy propyl methylcellulose K4M (HPMC K4M). The polymers had demonstrated considerable influence for all reactions. Ethylcellulose, a naturally impermeable material, was employed as a backing layer. The direct compression approach was used to create nine distinct losartan potassium formulations. Drug and polymer compatibility was determined through preformulation research utilizing fourier transform infrared (FTIR) spectroscopy. Buccoadhesive tablets were evaluated by swelling, bioadhesive characteristics, pH and in-vitro drug dissolution. The bioadhesive strength of guar gum was found to be greater than that of HPMC K4M. The swelling effect provided by both polymers was adequate. All formulations were judged to have an adequate surface pH, with values falling between 7 and 5, suggesting no discomfort to the buccal cavity. Ex-vivo residence times ranging from 7.2 to >10 hours for all tablets tested demonstrated a high degree of adhesion. The improved formulation follows Fickian diffusion release process. The optimized formulation underwent a stability investigation in accordance with International Council for Harmonisation (ICH) criteria, and no significant changes were found.

PH-responsive bentonite nanoclay carriers control the release of benzothiazolinone to restrain bacterial wilt disease

Ralstonia solanacearum (R. solanacearum) is one of the most devastating pathogens in terms of losses in agricultural production. Bentonite (Bent) is a promising synergistic agent used in development of effective and environmentally friendly pesticides against plant disease. However, the synergistic mechanism of Bent nanoclays with benzothiazolinone (BIT) against R. solanacearum is unknown. In this work, acid-functionalized porous Bent and cetyltrimethylammonium bromide (CTAB) were employed as the core nanoclays, and BIT was loaded into the clay to form BIT-loaded CT-Bent (BIT@CT-Bent) for the control of bacterial wilt disease. BIT@CT-Bent exhibited pH-responsive release behavior that fit the Fickian diffusion model, rapidly releasing BIT in an acidic environment (pH = 5.5). The antibacterial effect of BIT@CT-Bent was approximately 4 times greater than that of the commercial product BIT, and its biotoxicity was much lower than that of BIT under the same conditions. Interestingly, R. solanacearum attracted BIT@CT-Bent into the nanocomposites and induced cytoplasmic leakage and changes in membrane permeability, indicating an efficient and synergistic bactericidal effect that rapidly reduced bacterial density. In addition, BIT@CT-Bent significantly inhibited R. solanacearum biofilm formation and swimming activity, by suppressing the expression of phcA, solR and vsrC. Indeed, exogenous application of BIT@CT-Bent significantly suppressed the virulence of R. solanacearum on tobacco plants, with control effect of 75.48%, 72.08% and 66.08% at 9, 11 and 13 days after inoculation, respectively. This study highlights the potential of using BIT@CT-Bent as an effective, eco-friendly bactericide to control bacterial wilt diseases and for the development of sustainable crop protection strategies.

Multivitamin complex-loaded electrospun polyvinyl alcohol core/shell structure fibers for transdermal delivery system: In-silico and experimental studies

Transdermal delivery systems offer a controlled and targeted environment for releasing drugs compared to other delivery systems. This study presents the fabrication of polyvinyl alcohol (PVA) fibers with a multivitamin complex (MV) using the electrospinning technique (ES). The research focuses on understanding how various fiber structures, such as core/shell, simple fibers, and ES parameters, affect the MC release mechanism and cell viability behavior.The vitamin complexes were uniformly encapsulated within the polymeric chains in all structure fibers. PVA simple fibers with and without the vitamin complex don't significantly differ in diameter size. However, the core/Shell fiber has a notable decrease in fiber diameter of 45 %.The fiber with a core/shell structure resulted in a slower release rate of the vitamin complex than simple fiber. According to the Korsmeyer-Peppas model, the release mechanism observed in our study for the simple fibers is classical Fickian diffusion. Instead, core/shell fibers indicate a more anomalous or non-Fickian behavior.The structural configurations of the fibers do not result in statistically significant differences in cell viability. This could be attributed to the identical nature of materials used, including the polymer and MV, across all cases.Finally, a computational chemistry study was used to examine the interaction between polyvinyl alcohol (PVA) and vitamins K3 and B3, like a model of MV. The analysis showed four strong hydrogen bonds between PVA and vitamin B3, whereas the interaction between PVA and vitamin K3 only had one hydrogen bond. Furthermore, the PVA and vitamin B3 interaction had higher energy and was more exothermic and spontaneous than the PVA-vitamin K3 interaction. On the other hand, the PVA-vitamin K4 interaction displayed higher reactivity due to its lower separation energy. In contrast, the PVA-vitamin B3 interaction was more stable.