Prediction of directional solidification in freeze casting of biomaterial scaffolds using physics-informed neural networks.

Freeze casting, a manufacturing technique widely applied in biomedical fields for fabricating biomaterial scaffolds, poses challenges for predicting directional solidification due to its highly nonlinear behavior and complex interplay of process parameters. Conventional numerical methods, such as computational fluid dynamics (CFD), require adequate and accurate boundary condition knowledge, limiting their utility in real-world transient solidification applications due to technical limitations. In this study, we address this challenge by developing a physics-informed neural networks (PINNs) model to predict directional solidification in freeze-casting processes. The PINNs model integrates physical constraints with neural network predictions, requiring significantly fewer predetermined boundary conditions compared to CFD. Through a comparison with CFD simulations, the PINNs model demonstrates comparable accuracy in predicting temperature distribution and solidification patterns. This promising model achieves such a performance with only 5000 data points in space and time, equivalent to 250,000 timesteps, showcasing its ability to predict solidification dynamics with high accuracy. The study's major contributions lie in providing insights into solidification patterns during freeze-casting scaffold fabrication, facilitating the design of biomaterial scaffolds with finely tuned microstructures essential for various tissue engineering applications. Furthermore, the reduced computational demands of the PINNs model offer potential cost and time savings in scaffold fabrication, promising advancements in biomedical engineering research and development.

PVA-based formulations as a design-technology platform for orally disintegrating film matrices.

In the majority of pharmaceutical applications, polymers are employed extensively in a diverse range of pharmaceutical products, serving as indispensable components of contemporary solid oral dosage forms. A comprehensive understanding of the properties of polymers and selection the appropriate methods of characterization is essential for the design and development of novel drug delivery systems and manufacturing processes. Orally disintegrating film (ODF) formulations are considered to be a potential substitute to traditional oral dosage forms and an alternative method of drug administration for children and uncooperative adult patients, including those with swallowing difficulties. A multitude of pharmaceutical formulations with varying mechanical and biopharmaceutical properties have emerged from the modification of the original polymeric bulk. Here we propose different formulation approaches, i.e. solvent casting (SC), 3D printing (3DP), electrospinning (ES), and lyophilization (LP) that enabled us to adjust the disintegration time and the release profile of poorly water soluble haloperidol (HAL, BCS class II) from PVA (polyvinyl alcohol) based polymer films while maintaining similar hydrogel composition. In this study, the solubility of haloperidol in aqueous solution was improved by the addition of lactic acid. The prepared films were evaluated for their morphology (SEM, micro-CT), physicochemical and biopharmaceutical properties. TMDSC, TGA and PXRD were employed for extensive thermal and structural analysis of fabricated materials and their stability. These results allowed us to establish correlations between preparation technology, structural characteristics and properties of PVA films and to adapt the suitable manufacturing technique of the ODFs to achieve appropriate HAL dissolution behaviour.

Effect of bioceramic inclusions on gel-cast aliphatic polymer membranes for bone tissue engineering applications: An in vitro study.

BACKGROUND: Polylactic acid (PLA) has been extensively used in tissue engineering. However, poor mechanical properties and low cell affinity have limited its pertinence in load bearing bone tissue regeneration (BTR) devices. OBJECTIVE: Augmenting PLA with ß-Tricalcium Phosphate (ß-TCP), a calcium phosphate-based ceramic, could potentially improve its mechanical properties and enhance its osteogenic potential. METHODS: Gels of PLA and ß-TCP were prepared of different % w/w ratios through polymer dissolution in acetone, after which polymer-ceramic membranes were synthesized using the gel casting workflow and subjected to characterization. RESULTS: Gel-cast polymer-ceramic constructs were associated with significantly higher osteogenic capacity and calcium deposition in differentiated osteoblasts compared to pure polymer counterparts. Immunocytochemistry revealed cell spreading over the gel-cast membrane surfaces, characterized by trapezoidal morphology, distinct rounded nuclei, and well-aligned actin filaments. However, groups with higher ceramic loading expressed significantly higher levels of osteogenic markers relative to pure PLA membranes. Rule of mixtures and finite element models indicated an increase in theoretical mechanical strength with an increase in ß-TCP concentration. CONCLUSION: This study potentiates the use of PLA/ß-TCP composites in load bearing BTR applications and the ability to be used as customized patient-specific shape memory membranes in guided bone regeneration.

DES-YOLO: a novel model for real-time detection of casting surface defects.

Surface defect inspection methods have proven effective in addressing casting quality control tasks. However, traditional inspection methods often struggle to achieve high-precision detection of surface defects in castings with similar characteristics and minor scales. The study introduces DES-YOLO, a novel real-time method for detecting castings' surface defects. In the DES-YOLO model, we incorporate the DSC-Darknet backbone network and global attention mechanism (GAM) module to enhance the identification of defect target features. These additions are essential for overcoming the challenge posed by the high similarity among defect characteristics, such as shrinkage holes and slag holes, which can result in decreased detection accuracy. An enhanced pyramid pooling module is also introduced to improve feature representation for small defective parts through multi-layer pooling. We integrate Slim-Neck and SIoU bounding box regression loss functions for real-time detection in actual production scenarios. These functions reduce memory overhead and enable real-time detection of surface defects in castings. Experimental findings demonstrate that the DES-YOLO model achieves a mean average precision (mAP) of 92.6% on the CSD-DET dataset and a single-image inference speed of 3.9 milliseconds. The proposed method proves capable of swiftly and accurately accomplishing real-time detection of surface defects in castings.

Comparison of oven drying and freeze drying methods for the production of fast melt films containing quetiapine fumarate.

BACKGROUND: Quetiapine fumarate (QTP) is commonly prescribed for schizophrenic patient, typically available in tablet or oral suspension form, presenting challenges such as administration difficulties, fear of choking and distaste for its bitter taste. Fast melt films (FMF) offer an alternative dosage form with a simple development process, ease of administration and rapid drug absorption and action onset. OBJECTIVE: This study aims to prepare FMF with different formulations using solvent casting methods and to compare the effects of different drying methods, including oven drying and freeze drying, on the properties of the films. METHODS: Various formulations were created by manipulating polymer types (starch, hydroxypropyl methylcellulose (HPMC) and guar gum) at different concentrations, along with fixed concentrations of QTP and other excipients. Characterisation tests including surface morphology, weight, thickness, pH, tensile strength, elongation length, Young's modulus, folding endurance and disintegration time were conducted. The optimal FMF formulation was identified and further evaluated for moisture and drug content, dissolution behaviour, accelerated stability, X-ray diffraction (XRD), and palatability. RESULTS: FMF containing 10 mg guar gum/film developed using oven drying emerged as the optimum choice, exhibiting desirable film appearance, ultra-thin thickness (0.453 ± 0.002 mm), appropriate pH for oral intake (pH 5.0), optimal moisture content of 11.810%, rapid disintegration (52.67 ± 1.53 seconds), high flexibility (folding endurance > 300 times) and lower Young's modulus (1.308 ± 0.214). CONCLUSION: Oven drying method has been proven to be favourable for developing FMF containing QTP, meeting all testing criteria and providing an alternative option for QTP prescription.

Treating a case of diabetic stump ulceration after Chopart's amputation with total contact casting.

Chopart's amputation is a limb length-preserving amputation that retains function but often suffers from stump ulcerations. We report a case of a 68-year-old male patient with poorly controlled type 2 diabetes mellitus and peripheral arterial disease who underwent left Chopart's amputation, presenting subsequently with nonhealing ulcers at the Chopart stump and heel for >1 year. Total contact casting was initiated, resulting in rapid wound healing without further interventions. This case highlights total contact casting's effectiveness in managing ulcerations post-Chopart's amputation, potentially preventing revision amputations, and extending its usefulness to complex foot anatomy in patients with diabetes and peripheral arterial disease.

Accuracy of conventional versus additive cast-fabrication in implant prosthodontics: A systematic review and meta-analysis of in vitro studies.

PURPOSE: Additive cast-fabrication has yet to be used as commonly in implant prosthodontics as conventional methods. This review aimed to investigate the accuracy of additive cast-fabrication in implant prosthodontics. STUDY SELECTION: The study protocol was registered in the PROSPERO database (CRD42022374972). Reporting was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, following the Cochrane Handbook. Two-arm interventional studies that matched the PICO were included (Population: dental typodonts with implants, Intervention: additive cast-fabrication, Comparator: conventional cast-fabrication, Outcome: positional deviations). A systematic search was conducted in three databases: PubMed (MEDLINE), EMBASE, and the Cochrane Library (CENTRAL). RESULTS: Seven papers were included in the analysis of horizontal, vertical, and root mean square (RMS) deviations. No significant differences were observed between groups. The overall vertical mean deviation of the intervention group was -4.15 µm [-24.88; 16.57], and the pooled mean absolute deviation was 22.43 µm [8.33; 36.54]. In the control group, these values were 19.67 µm [-32.71; 72.04] and 24.62 µm [0.00; 59.42], respectively. The overall horizontal mean deviation in the intervention group was 21.29 µm [-77.10; 119.68], and the pooled mean absolute deviation was 26.96 µm [0.00; 70.81]. In the control group, the overall mean was 1.45 µm [-32.26; 35.15] and the pooled mean absolute deviation was 25.05 µm [9.08; 41.01]. The mean RMS was only slightly larger in the intervention group, with the value of 14.74 µm [-107.26; 136.74]. CONCLUSIONS: Additive cast-fabrication is as accurate as the conventional method for the position of implant analogs.

Migration and retention of human osteosarcoma cells in bioceramic graft with open channel architecture designed for bone tissue engineering.

The microstructure of a porous bioceramic bone graft, especially the pore architecture, plays a crucial role in the performance of the graft. Conventional bioceramic grafts typically feature a random, closed-pore structure, limiting biological activity to the periphery of the graft. This can lead to delay in full integration with the host site. Bioceramic forms with open through pores can perform better because their inner regions are accessible for natural bone remodeling. This study explores the influence of open through pores in a bioceramic graft on the migration and retention of the local cellsin vitro, which will correlate to the rate of healingin vivo.Hydroxyapatite ceramic forms with aligned channels were fabricated using slip casting technique, employing sacrificial fibers. The sorption characteristics across the graft were evaluated using human osteosarcoma cell line. Seven-day cultures showed viable cells within the channels, confirmed by live/dead assay, scanning electron microscope analysis, and cytoskeletal staining, indicating successful cell colonization. The channel architecture effectively enhances cell migration and retention throughout its entire structure, suggesting potential applications in bone tissue engineering based on the results obtained.

A novel nonlinear pressurization method for counter-gravity casting of cross-sectional mutation structures.

In order to ensure the filling integrity of complex counter-gravity casting and improve metallurgical quality, it is necessary to shorten the filling time while avoiding air entrainments. To address this contradiction, a novel nonlinear pressurization method was proposed in this study. Through systematically analyzing the relationship between critical gating velocity and stable filling height, a criterion for iterative calculation of nonlinear pressurization curve was established, and an empirical expression between nonlinear pressurizing speed and the filling height was obtained. Based on the empirical expression, a nonlinear pressurization curve can be designed according to the casting structures and initial pressurizing speeds. The above nonlinear pressure curve design method was validated through water filling experiments. It was proved that the nonlinear pressure curve can shorten the filling time while avoiding air entrainments. It provides important processing control method for improving the low-pressure casting performance of complex castings.

Rapid Tissue Perfusion Using Sacrificial Percolation of Anisotropic Networks.

Tissue engineering has long sought to rapidly generate perfusable vascularized tissues with vessel sizes spanning those seen in humans. Current techniques such as biological 3D printing (top-down) and cellular self-assembly (bottom-up) are resource intensive and have not overcome the inherent tradeoff between vessel resolution and assembly time, limiting their utility and scalability for engineering tissues. We present a flexible and scalable technique termed SPAN - Sacrificial Percolation of Anisotropic Networks, where a network of perfusable channels is created throughout a tissue in minutes, irrespective of its size. Conduits with length scales spanning arterioles to capillaries are generated using pipettable alginate fibers that interconnect above a percolation density threshold and are then degraded within constructs of arbitrary size and shape. SPAN is readily used within common tissue engineering processes, can be used to generate endothelial cell-lined vasculature in a multi-cell type construct, and paves the way for rapid assembly of perfusable tissues.

Cassava bagasse starch and oregano essential oil as a potential active food packaging material: A physicochemical, thermal, mechanical, antioxidant, and antimicrobial study.

This research evaluates the use of cassava bagasse starch and oregano essential oil (OEO) in an active film. For comparison, films of cassava starch (CS) and cassava bagasse starch (BS) were prepared with OEO at 1, 2, and 3 %. Physical, thermal, mechanical, antioxidant, and antimicrobial properties were determined. BS films presented higher thickness, WVP, ΔE, modulus of elasticity, and maximum stress, but lower strain at break compared to CS films. Adding OEO into the films increased their thickness, moisture, solubility, WVP and strain at break. However, maximum stress, modulus of elasticity, and T dmax decreased. The CS films added with 3 % of OEO showed higher WVP (6.32 × 10-14 kg m/m2.s.Pa), intermediate solubility of 39 % and low maximum stress (0.19 MPa) while the BS film with 3 % of OEO presented 5.73 × 10-14 kg m/m2.s.Pa, 30 % and 0.39 MPa, respectively. The increase from 1 % to 3 % of OEO increased the total phenolic compound content and antioxidant activity of the films by 1.3-fold and 3.7-fold, respectively. The incorporation of 3 % OEO in the films inhibited the growth of S. aureus and E. coli. Therefore, BS and OEO films offer a promising solution as biodegradable active food packaging, providing a more sustainable alternative to traditional non-biodegradable plastic packaging.

Club Foot with Contralateral Congenital Amniotic Band Syndrome Amputation Successfully Treated with Ponseti Method: Case Report.

Introduction: Constriction amniotic band syndrome (CABS) is a rare condition associated with the fibrous amniotic bands that restrict and ensnare the fetus in utero resulting in malformations at birth in one per around 15,000 live births. CABS associated with clubfoot, historically required extensive soft-tissue release due to its propensity for relapse. Case Report: A 2-day-old Caucasian male infant born at 27 weeks gestation through emergency cesarean section due to concern for placental abruption and premature rupture of membranes in the setting of a prenatal history significant for oligohydramnios. The patient presented with non-viable tissue in the right leg requiring amputation with a left-sided clubfoot deformity. Following amputation of the right leg, the clubfoot was corrected with Ponseti method of serial casting and Achilles tenotomy. Three-week post-tenotomy and 6 months of age, a custom fit prosthesis of the right leg allowed for the application of a left abduction foot orthosis which maintained the correction. Conclusion: This case study supports recent literature that CABS-associated clubfoot can be corrected with the Ponseti method. While a contralateral amputation can prevent the use of a traditional bilateral abduction foot orthosis, a custom fitted prosthesis can allow for its use and prevention of a relapse of deformity.

Early Biological Response to Poly(ε-Caprolactone)/Alumina-Toughened Zirconia Composites Obtained by 3D Printing for Peri-Implant Application.

The improvement of the mucosal sealing around the implant represents a challenge, one that prompted research into novel materials. To this purpose, a printable poly(ε-caprolactone) (PCL)-based composite loaded with alumina-toughened zirconia (ATZ) at increasing rates of 10, 20, and 40 wt.% was prepared, using a solvent casting method with chloroform. Disks were produced by 3D printing; surface roughness, free energy and optical contact angle were measured. Oral fibroblasts (PF) and epithelial cell (SG) tests were utilized to determine the biocompatibility of the materials through cell viability assay and adhesion and spreading evaluations. The highest level of ATZ resulted in an increase in the average roughness (Sa), while the maximum height (Sz) was higher for all composites than that of the unmixed PCL, regardless of their ATZ content. Surface free energy was significantly lower on PCL/ATZ 80/20 and PCL/ATZ 60/40, compared to PCL and PCL/ATZ 90/10. The contact angle was inversely related to the quantity of ATZ in the material. PF grew without variations among the different specimens at 1 and 3 days. After 7 days, PF grew significantly less on PCL/ATZ 60/40 and PCL/ATZ 80/20 compared to unmixed PCL and PCL 90/10. Conversely, ATZ affected and improved the growth of SG. By increasing the filler amount, PF cell adhesion and spreading augmented, while PCL/ATZ 80/20 was the best for SG adhesion. Overall, PCL/ATZ 80/20 emerged as the best composite for both cell types; hence, it is a promising candidate for the manufacture of custom made transmucosal dental implant components.

Optimization Design of Submerged-Entry-Nozzle Structure Using NSGA-II Genetic Algorithm in Ultra-Large Beam-Blank Continuous-Casting Molds.

To achieve uniform cooling and effective homogenization control in ultra-large beam-blank molds necessitates the optimization of submerged-entry-nozzle (SEN) structures. This study employed computational fluid dynamic (CFD) modeling to investigate the impact of two-port and three-port SEN configurations on fluid flow characteristics, free-surface velocities, temperature fields, and solidification behaviors. Subsequently, integrating numerical simulations with the non-dominated sorting genetic algorithm II (NSGA-II) and metallurgical quality-control expertise facilitated the multi-objective optimization of a three-port SEN structure suitable for beam-blank molds. The optimized parameters enabled the three-port SEN to deliver molten steel to the meniscus at an appropriate velocity while mitigating harmful effects such as SEN port backflow, excessive surface temperature differences, and shell thickness reduction due to fluid flow. The results indicated that the three-port SEN enhanced the molten-steel flow pattern and mitigated localized shell thinning compared with the two-port SEN. Additionally, the optimized design (op2) of the three-port SEN exhibited reduced boundary layer separation and superior fluid dynamics performance over the initial three-port SEN configuration.

Simulation Model of a Steelmaking-Continuous Casting Process Based on Dynamic-Operation Rules.

The steelmaking-continuous casting process (SCCP) is a complex manufacturing process which exhibits the distinct features of process manufacturing. The SCCP involves a variety of production elements, such as multiple process routes, a wide array of smelting and auxiliary devices, and a variety of raw and auxiliary materials. The production-simulation of SCCP holds a natural advantage in being able to accurately depict the intricate production behavior involved, and this serves as a crucial tool for optimizing the production operation of the SCCP. This paper thoroughly considers the various production elements involved in the SCCP, such as the fluctuation of the converter smelting cycle, fluctuation of heat weight, and ladle operation. Based on the Plant Simulation software platform, a dynamic simulation model of the SCCP is established and detailed descriptions are provided regarding the design of an SCCP using dynamic-operation rules. Additionally, a dynamic operational control program for the SCCP is developed using the SimTalk language, one which ensures the continuous operation of the caster in the SCCP, using the discrete simulation platform. The effectiveness of the proposed dynamic simulation model is verified by the total completion time of the production plan, the transfer time of the heat among the different processes, and the frequency of ladle turnover. The simulation's results indicate that the dynamic simulation model has a satisfactory effect in simulating the actual production process. On this basis, the application effects of different schedules are compared and analyzed. Compared with a heuristic schedule, the optimized schedule based on the "furnace-machine coordinating" mode reduces the weighted value of total completion time by 8.7 min, reduces the weighted value of transfer waiting time by 45.5 min, and the number of rescheduling times is also reduced, demonstrating a better application effect and verifying the optimizing effect of the "furnace-machine coordinating" mode on the schedule.

The Influence of Thermomechanical Conditions on the Hot Ductility of Continuously Cast Microalloyed Steels.

Continuous casting is the most common method for producing steel into semi-finished shapes like billets or slabs. Throughout this process, steel experiences mechanical and thermal stresses, which influence its mechanical properties. During continuous casting, decreased formability in steel components leads to crack formation and failure. One reason for this phenomenon is the appearance of the soft ferrite phase during cooling. However, it is unclear under which conditions this ferrite is detrimental to the formability. In the present research, we investigated what microstructural changes decrease the formability of microalloyed steels during continuous casting. We studied the hot compression behaviour of microalloyed steel over temperatures ranging from 650 °C to 1100 °C and strain rates of 0.1 s-1 to 0.001 s-1 using a Gleeble 3800® (Dynamic Systems Inc, Poestenkill, NY, USA) device. We examined microstructural changes at various deformation conditions using microscopy. Furthermore, we implemented a physically-based model to describe the deformation of austenite and ferrite. The model describes the work hardening and dynamic restoration mechanisms, i.e., discontinuous dynamic recrystallisation in austenite and dynamic recovery in ferrite and austenite. The model considers the stress, strain, and strain rate distribution between phases by describing the dynamic phase transformation during the deformation in iso-work conditions. Increasing the strain rate below the transformation temperature improves hot ductility by reducing dynamic recovery and strain concentration in ferrite. Due to limited grain boundary sliding, the hot ductility improves at lower temperatures (<750 °C). In the single-phase domain, dynamic recrystallisation improves the hot ductility provided that fracture occurs at strains in which dynamic recrystallisation advances. However, at very low strain rates, the ductility decreases due to prolonged time for grain boundary sliding and crack propagation.

Effect of Casting Process and Thermal Exposure on Microstructure and Mechanical Properties of Al-Si-Cu-Ni Alloy.

This paper employed squeeze-casting (SC) technology to develop a novel Al-7Si-1.5Cu-1.2Ni-0.4Mg-0.3Mn-0.15Ti heat-resistant alloy, addressing the issue of low room/high temperature elongation in traditional gravity casting (GC). Initially, the effects of SC and GC processes on the microstructure and properties of the alloy were investigated, followed by an examination of the evolution of the microstructure and properties of the SC samples over thermal exposure time. The results indicate that the SC process significantly improves the alloy's microstructure. Compared to the GC alloy, the secondary dendrite arm spacing of the as-cast SC alloy is refined from 50.5 µm to 18.5 µm. Meanwhile, the size and roundness of the eutectic Si phase in the T6-treated SC alloy are optimized from 11.7 µm and 0.75 µm to 9.5 µm and 0.85 µm, respectively, and casting defects such as porosity are reduced. Consequently, the ultimate tensile strengths (UTSs) at room temperature and at 250 °C of the SC alloy are 5% and 4.9% higher than that of GC alloy, respectively, and its elongation at both temperatures shows significant improvement. After thermal exposure at 250 °C for 120 h, the morphology of the residual second phase at the grain boundaries in the SC alloy becomes more rounded, but the eutectic Si and nano-precipitates undergo significant coarsening, resulting in a 49% decrease in UTS.

Recent Advancements in Fabrication of Metal Matrix Composites: A Systematic Review.

Metal matrix composites (MMCs) are essential materials in various industries due to superior properties, such as high strength-to-weight ratios, better corrosion resistance, improved wear resistance and adaptability, developed by continuous improvements in their fabrication methods. This helps to meet the growing demand for high-performance and sustainable products. The industries that stand to gain the most are automotive and aerospace, where MMCs are used for car parts, airplane frames, and jet engines that need to be strong and lightweight. Furthermore, MMCs are being extensively used in the biomedical industry for implants and medical equipment because of their suitable mechanical integrity and corrosion resistance. Applications in heavy construction, defense, and even space exploration are noteworthy. The advancements in fabrication of MMCs have revolutionized the composite industry with their improved mechanical, tribological, and metallurgical properties. This review article offers an introduction and thorough examination of the most recent advancements (mostly within the last five years) in fabrication methods of MMCs. The novelty and modernization in the traditional processes and advanced processes are covered, along with discussing the process parameters' effects on the microstructure and properties of the composites. The review focuses on features and prospective applications of MMCs that have been greatly improved and extended due to such advancements. The most recent methods for developing MMCs, including friction stir processing (FSP), ultrasonic-assisted stir casting, and additive manufacturing, are discussed. Artificial intelligence and machine learning interventions for composite manufacturing are also included in this review. This article aims to assist researchers and scholars and encourage them to conduct future research and pursue innovations to establish the field further.

Effect of the molar mass of chitosan and film casting solvents on the properties of chitosan films loaded with Mentha spicata essential oil for potential application as wound dressing.

Chitosan based films endowed with antibacterial features have witnessed remarkable progress as potential wound dressings. The current study aimed at appraising the effects of the molar mass of chitosan (MM) and the film casting acids on the properties of unplasticized chitosan films and plasticized MSO-embedded chitosan films in order to provide best suited film formulation as a potential candidate for wound dressing application. The prepared films were functionally characterized in terms of their qualitative assessment, thickness, density, swelling behavior, water vapor barrier, mechanical and antibacterial properties. Overall, all chitosan films displayed thickness lower than the human dermis even though thicker and denser films were produced with lactic acid. Assessment of the swelling behavior revealed that only high molar mass (HMM) chitosan films may be regarded as absorbent dressings. Moreover, unplasticized HMM lactate (HMM-LA) films furnished lower stiffness and higher percent strain break as compared to acetate films, due to the plasticizing effect of the remaining lactic acid as alluded by the FTIR analysis. Meanwhile, they provided suitable level of moisture and indicated substantial antibacterial activity against S. aureus and E. coli, the most commonly opportunistic bacteria found in infected skin wound. Plasticized chitosan films doped with MSO were significantly thicker and more permeable to water compared to unplasticized films. Furthermore, MSO significantly potentiate the antibacterial effect of chitosan-based films. Therefore, plasticized HMM-LA/MSO chitosan film flashing good swelling behavior, adequate WVTR and WVP, suitable mechanical properties and antibacterial performances substantiated to be a promising antibacterial dressing material for moderately exuding wounds.

A novel macroporous carboxymethyl chitosan/sodium alginate sponge dressing capable of rapid hemostasis and drug delivery.

Carboxymethyl chitosan (CMCS) and sodium alginate (SA), which are excellent polysaccharide-based hemostatic agents, are capable of forming polyelectrolyte complexes (PEC) through electrostatic interactions. However, CMCS/SA PEC sponges prepared by the conventional sol-gel process exhibited slow liquid absorption rate and poor mechanical properties post-swelling. In this work, a novel strategy involving freeze casting followed by acetic acid vapor treatment to induce electrostatic interactions was developed to fabricate novel PEC sponges with varying CMCS/SA mass ratios. Compared to sol-gel process sponge, the novel sponge exhibited a higher density of electrostatic interactions, resulting in denser pore walls that resist re-gelation and swelling according to FTIR, XRD, and SEM analyses. Additionally, the liquid absorption kinetics, as well as compression and tension tests, demonstrated that the novel sponge had significantly improved rapid blood absorption capacity and mechanical properties. Furthermore, in vitro coagulation and drug release studies showed that the novel sponge had a lower blood clotting index and clotting time, along with a slower drug release rate after loading with berberine hydrochloride, showcasing its potential as a rapid hemostatic dressing with controlled drug release capabilities.