Preparation and Characterization of Alginate Hydrogel Fibers Reinforced by Cotton for Biomedical Applications

Current trend on preparation, characterization and biomedical applications of natural polysaccharide-based nanomaterial reinforcement hydrogels: A review

The tunable properties of hydrogels have led to their widespread use in various biomedical applications such as wound treatment, drug delivery, contact lenses, tissue engineering and 3D bioprinting. Among these applications, natural polysaccharide-based hydrogels, which are fabricated from materials like agarose, alginate, chitosan, hyaluronic acid, cellulose, pectin and chondroitin sulfate, stand out as preferred choices due to their biocompatibility and advantageous fabrication characteristics. Despite the inherent biocompatibility, polysaccharide-based hydrogels on their own tend to be weak in physiochemical and mechanical properties. Therefore, further reinforcement in the hydrogel is necessary to enhance its suitability for specific applications, ensuring optimal performance in diverse settings. Integrating nanomaterials into hydrogels has proven effective in improving the overall network and performance of the hydrogel. This approach also addresses the limitations associated with pure hydrogels. Next, an overview of recent trends in the fabrication and applications of hydrogels was presented. The characterization of hydrogels was further discussed, focusing specifically on the reinforcement achieved with various hydrogel materials used so far. Finally, a few challenges associated with hydrogels by using polysaccharide-based nanomaterial were also presented.

Optimization of the novel jute retting process to enhance the fiber quality for textile applications

This study introduces an innovative chemical retting approach, systematically optimized via Grey relational analysis, to achieve jute fibers that exhibit desirable characteristics of softness, high tensile strength, and suitability for spinning, with a particular focus on their application in the apparel industry. In this study, the effect of alkali treatment (alkali concentration, temperature and duration of retting) on jute fiber's chemical composition and mechanical characteristics was investigated. Jute fibers were treated at three concentrations (5 %, 10 %, 15 %) of alkali, at three different temperature (30 °C, 60 °C, & 90 °C) and for three different retting duration (12 h, 24 h, & 36 h). The surface morphology and crystallinity of fibers were analyzed using optical microscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The fiber linear density and mechanical characteristics were also tested. The multi-response optimization of all the factors and the responses was investigated using the Grey relational analysis. The results showed that the fiber surface morphology and crystallinity increase with an increase in alkali concentration, retting time, and temperature. Chemical retting treatment also improved the fiber linear density and tensile strength. The finest fibers which were obtained in this research had a linear density of 2.18 Tex with a tenacity of 53.02 cN/tex and elongation of 4.54 %. The spinnable jute fibers were achieved after this treatment with excellent characteristics.

Functional Materials Made by Combining Hydrogels (Cross-Linked Polyacrylamides) and Conducting Polymers (Polyanilines)-A Critical Review

Hydrogels made of cross-linked polyacrlyamides (cPAM) and conducting materials made of polyanilines (PANIs) are both the most widely used materials in each category. This is due to their accessible monomers, easy synthesis and excellent properties. Therefore, the combination of these materials produces composites which show enhanced properties and also synergy between the cPAM properties (e.g., elasticity) and those of PANIs (e.g., conductivity). The most common way to produce the composites is to form the gel by radical polymerization (usually by redox initiators) then incorporate the PANIs into the network by oxidative polymerization of anilines. It is often claimed that the product is a semi-interpenetrated network (s-IPN) made of linear PANIs penetrating the cPAM network. However, there is evidence that the nanopores of the hydrogel become filled with PANIs nanoparticles, producing a composite. On the other hand, swelling the cPAM in true solutions of PANIs macromolecules renders s-IPN with different properties. Technological applications of the composites have been developed, such as photothermal (PTA)/electromechanical actuators, supercapacitors, movement/pressure sensors, etc. PTA devices rely on the absorption of electromagnetic radiation (light, microwaves, radiofrequency) by PANIs, which heats up the composite, triggering the phase transition of a thermosensitive cPAM. Therefore, the synergy of properties of both polymers is beneficial.

Synthesis and characterization of natural fibers reinforced alginate hydrogel fibers loaded with diclofenac sodium for wound dressings

Hydrogels which become increasingly important in the biomedical field are composed of a three-dimensional hydrophilic network. Pure hydrogels are usually weak and brittle; therefore, reinforcements are assimilated into the hydrogel structure to improve the mechanical strength of the hydrogels. However, even if mechanical properties are enhanced, drapability remains an issue. In that regard, natural fiber-reinforced composite hydrogel fibers for wound dressing application are investigated in this study. Kapok and hemp fibers were used as reinforcement to improve the strength of hydrogel fibers. The properties of the prepared composite hydrogel fibers were studied with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimeter (DSC). The effect of alginate concentration and fiber weight percent on the mechanical characteristics and water absorbency was studied. Diclofenac sodium drug was loaded in the hydrogel fibers and investigated the drug release as well as antibacterial characteristics. Both fibers' reinforcement enhanced the strength of the alginate hydrogel fiber, but hemp reinforcement showed better mechanical properties. Kapok reinforcement resulted in a maximum tensile strength of 174 cN (1.24 % elongation) and 432 % exudate absorbency, while hemp reinforcement resulted in 185 cN (1.48 % elongation) and 435 % exudate absorbency. Statistical analysis revealed significant effects of sodium alginate concentration on tensile strength (p-value 0.042) and exudate absorbency (p-value 0.020) and of reinforcement (wt%) on exudate absorbency (p-value 0.043). Therefore, these composite hydrogel fibers with improved mechanical properties are capable of drug release and exhibit antibacterial effectiveness, making them a promising option for use as wound dressings.