Preparation and characterization of konjac glucomannan–poly(acrylic acid) IPN hydrogels for controlled release

Alkaline-Responsive, Self-Healable, and Conductive Copolymer Composites with Enhanced Mechanical Properties Tailored for Wearable Tech

Despite significant advancements, current self-healing materials often suffer from a compromise between mechanical robustness and functional performance, particularly in terms of conductivity and responsiveness to environmental stimuli. Addressing this issue, the research introduces a self-healable and conductive copolymer, poly(ionic liquid-co-acrylic acid) (PIL-co-PAA), synthesized through free radical polymerization, and further optimized by incorporating thermoplastic polyurethane (TPU). This combination leverages the unique properties of each component, especially ion-dipole interactions and hydrogen bonds, resulting in a material that exhibits exceptional self-healing abilities and demonstrates enhanced mechanical properties and electrical conductivity. Moreover, the PIL-co-PAA/TPU films showcase alkaline-responsive behavior, a feature that broadens their applicability in dynamic environments. Through systematic characterization, including thermogravimetric analysis, tensile testing, and electrical properties measurements, the mechanisms behind the improved performance and functionality of these films are elucidated. The conductivities and ultimate tensile strength (σuts) of the PIL-co-PAA/TPU films regain 80% under 8 h healing process. To extend the applications for wearable devices, the self-healing properties of commercial cotton fabrics coated with the self-healable PIL-co-PAA are also investigated, demonstrating both self-healing and electrical properties. This study advances the understanding of self-healable conductive polymers and opens new avenues for their application in wearable technology.

Konjac glucomannan: A comprehensive review of its extraction, health benefits, and pharmaceutical applications

Konjac glucomannan (KG) is a dietary fiber hydrocolloid derived from Amorphophallus konjac tubers and is widely utilized as a food additive and dietary supplement. As a health-conscious choice, purified KG, along with konjac flour and KG-infused diets, have gained widespread acceptance in Asian and European markets. An overview of the chemical composition and structure of KG is given in this review, along with thorough explanations of the processes used in its extraction, production, and purification. KG has been shown to promote health by reducing glucose, cholesterol, triglyceride levels, and blood pressure, thereby offering significant weight loss advantages. Furthermore, this review delves into the extensive health benefits and pharmaceutical applications of KG and its derivatives, emphasizing its prebiotic, anti-inflammatory, and antitumor activities. This study highlights how these natural polysaccharides can positively influence health, underscoring their potential in various biomedical applications.

Crosslinking and Swelling Properties of pH-Responsive Poly(Ethylene Glycol)/Poly(Acrylic Acid) Interpenetrating Polymer Network Hydrogels

This study investigates the crosslinking dynamics and swelling properties of pH-responsive poly(ethylene glycol) (PEG)/poly(acrylic acid) (PAA) interpenetrating polymer network (IPN) hydrogels. These hydrogels feature denser crosslinked networks compared to PEG single network (SN) hydrogels. Fabrication involved a two-step UV curing process: First, forming PEG-SN hydrogels using poly(ethylene glycol) diacrylate (PEGDA) through UV-induced free radical polymerization and crosslinking reactions, then immersing them in PAA solutions with two different molar ratios of acrylic acid (AA) monomer and poly(ethylene glycol) dimethacrylate (PEGDMA) crosslinker. A subsequent UV curing step created PAA networks within the pre-fabricated PEG hydrogels. The incorporation of AA with ionizable functional groups imparted pH sensitivity to the hydrogels, allowing the swelling ratio to respond to environmental pH changes. Rheological analysis showed that PEG/PAA IPN hydrogels had a higher storage modulus (G') than PEG-SN hydrogels, with PEG/PAA-IPN5 exhibiting the highest modulus. Thermal analysis via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated increased thermal stability for PEG/PAA-IPN5 compared to PEG/PAA-IPN1, due to higher crosslinking density from increased PEGDMA content. Consistent with the storage modulus trend, PEG/PAA-IPN hydrogels demonstrated superior mechanical properties compared to PEG-SN hydrogels. The tighter network structure led to reduced water uptake and a higher gel modulus in swollen IPN hydrogels, attributed to the increased density of active network strands. Below the pKa (4.3) of acrylic acid, hydrogen bonds between PEG and PAA chains caused the IPN hydrogels to contract. Above the pKa, ionization of PAA chains induced electrostatic repulsion and osmotic forces, increasing water absorption. Adjusting the crosslinking density of the PAA network enabled fine-tuning of the IPN hydrogels' properties, allowing comprehensive comparison of single network and IPN characteristics.

Effects of different oil fractions and tannic acid concentrations on konjac glucomannan-stabilized emulsions

Polysaccharide-stabilized emulsions have received extensive attention, but emulsifying activity of polysaccharides is poor. In this study, konjac glucomannan (KGM) and tannic acid (TA) complex (KGM-TA) was prepared via non-covalent binding to increase the polysaccharide interfacial stability. The emulsifying stabilities of KGM-TA complex-stabilized emulsions were analyzed under different TA concentrations and oil fractions. The results indicated that hydrogen bonds and hydrophobic bonds were the main binding forces for KGM-TA complex, which were closely related to TA concentrations. The interfacial tension of KGM-TA complex decreased from 20.0 mN/m to 13.4 mN/m with TA concentration increasing from 0 % to 0.3 %, indicating that TA improved the interfacial activity of KGM. Meanwhile, the contact angle of KGM-TA complex was closer to 90° with the increasing TA concentrations. The emulsifying stability of KGM-TA complex-stabilized emulsions increased in an oil mass fraction-dependent manner, reaching the maximum at 75 % oil mass fraction. Moreover, the droplet sizes of KGM-TA complex-stabilized high-internal-phase emulsions (HIPEs) decreased from 82.7 μm to 44.7 μm with TA concentration increasing from 0 to 0.3 %. Therefore, high TA concentrations were conducive to the improvement of the emulsifying stability of KGM-TA complex-stabilized HIPEs. High oil mass fraction promoted the interfacial contact of adjacent droplets, thus enhancing the non-covalent binding of KGM molecules at the interfaces with TA as bridges. Additionally, the high TA concentrations increased the gel network density in the aqueous phase, thus enhancing the emulsifying stability of emulsions. Our findings reveal the mechanisms by which polysaccharide-polyphenol complex stabilized HIPEs. Therefore, this study provides theoretical basis and references for the developments of polysaccharide emulsifier with high emulsifying capability and high-stability emulsions.

Rapidly degradable konjac glucomannan hydrogels cross-linked with olsalazine for colonic drug release

BACKGROUND

Polysaccharide hydrogel is one of the most important materials for the colon target drug release system. However, the degradation time of polysaccharide hydrogel is much longer than the retention time in the colon. The drugs are expelled from the body before being released.

OBJECTIVE

In order to match the degradation of drug carriers and their retention time in the colon, a rapidly degradable konjac glucomannan (KGM) hydrogel was designed for colon target drug release.

METHODS

A crosslinker containing azo bond, olsalazine, was used to prepare the rapidly degradable KGM hydrogel. The degradation and drug release of the hydrogels with different crosslinking densities in the normal buffer and the human fecal medium were studied to evaluate the efficiency of colon drug release.

RESULTS

More than 50% of the KGM hydrogel by weight was degraded and more than 60% of the 5-fluorouracil (5-Fu) was released within 48 h in 5% w/v human fecal medium.

CONCLUSION

The drug was released more rapidly in a simulated colon environment than in a normal buffer. Furthermore, the drug release was controlled by the degradation of the hydrogel. The KGM hydrogel containing azo crosslinker has great potential for colon drug release.

Preparation and Application of Double Network Interpenetrating Colon Targeting Hydrogel Based on Konjac Glucomannan and N-Isopropylacrylamide

Konjac glucomannan (KGM) can be degraded by colon-specific enzymes in the colonic environment, making it one of the materials for treating colonic diseases, which has attracted more and more attention. However, during drug administration, especially in the gastric environment and due to its easy swelling, the structure of KGM is usually destroyed and the drug is released, thereby reducing the bioavailability of the drug. To solve this problem, the easy swelling and drug release properties of KGM hydrogels are avoided by creating interpenetrating polymer network hydrogels. In this study, N-isopropylacrylamide (NIPAM) is first formed into a hydrogel framework under the action of a cross-linking agent to stabilize the gel shape before the gel is heated under alkaline conditions to make KGM molecules wrap around the NIPAM framework. The structure of the IPN(KGM/NIPAM) gel was confirmed using Fourier transform infrared spectroscopy (FT-IR) and x-ray diffractometer (XRD). In the stomach and small intestine, it was found that the release rate and swelling rate of the gel were 30% and 100%, which were lower than 60% and 180% of KGM gel. The experimental results showed that this double network hydrogel has a good colon-directed release profile and fine drug carrier ability. This provides a new idea for the development of konjac glucomannan colon-targeting hydrogel.

Effect of konjac glucomannan with different viscosities on the quality of surimi-wheat dough and noodles

It was investigated that the rheology, starch-gluten-surimi network, thermal properties, and water distribution of surimi-wheat dough, and texture characteristics, cooking properties, and microscopic characteristics of the surimi-wheat noodles with konjac glucomannan (KGM) of different viscosities in different concentrations. The results showed that the storage (G'), loss (G″), and complex (G⁎) moduli of dough increased with adding KGM. With the increase of KGM viscosity, the reduction in the free sulfhydryl (SH) content to 0.84 μmol/g and the increase in the free water content to 8.25 % led to significantly improved enthalpy and the microstructure density. The hardness and tensile length of noodles were substantially increased by adding 3 % KGM. In addition, the KGM enhanced the starch-gluten-surimi network and improved the cooking qualities and textural properties of noodles. More importantly, the application of KGM in the wheat flour composite system also showed better performance. Thus, the introduction of KGM into the surimi-wheat dough had a significant effect on the optimization of the macro- and micro-characteristics of dough and noodles.

Physically Crosslinked Hydrogels Based on Poly (Vinyl Alcohol) and Fish Gelatin for Wound Dressing Application: Fabrication and Characterization

We developed the interpenetrating double network composite hydrogel based on poly (vinyl alcohol) (PVA) and fish gelatin (FG) via thermal treatment and repeated freeze-thawing. A function of salicylic acid was incorporated into the hydrogel to improve its antibacterial properties. The color values, water contents, water evaporation rate, and swelling behavior were investigated. The drug-loading performance of the composite hydrogel was demonstrated by loading salicylic acid in various hydrogel systems. Moreover, the cumulative dissolution percentage of salicylic acid and the antibacterial activity of composite hydrogel were carried out. The results revealed that as FG concentration increased from 0% to 3.75% (w/v), gels changed from white to slight yellow and the swelling ratio increased from 54% to 83% (within 8 h). The presence of FG decreased the water content of gels which ranged from 86% to 89% and also decreased water evaporation rate. All gels presented the swelling index within 0.5-1.0, indicating a non-Fickian diffusion mechanism. The drug sustained dissolution behavior of pure PVA and composite hydrogel showed the same trend. Besides, the presence of the obvious bacteriostatic zones means that drug-loaded composite hydrogels have an effective antibacterial property. These results demonstrated that PVA/FG-based interpenetrating hydrogel is an appropriate biomaterial for drug-carrying wound dressing application.

Proanthocyanidin-crosslinked collagen/konjac glucomannan hydrogel with improved mechanical properties and MRI trackable biodegradation for potential tissue engineering scaffolds

Collagen (Col) has been intensively exploited as a biomaterial for its excellent biocompatibility, biodegradation and bioactivity. However, the poor mechanical properties and rapid biodegradation of reconstituted collagen hydrogels have always been the bottlenecks for their further development especially for vascular tissue engineering. Herein, based on the self-assembly characteristics of collagen, a ternary hydrogel scaffold, comprising rigid collagen molecules, flexible konjac glucomannan (KGM) chains and biocompatible crosslinkers of proanthocyanidin (PA), has been designed to achieve a synergistic interaction for essentially optimizing the mechanical properties of the so-obtained Col/KGM/PA hydrogel, which possesses not only substantially improved strength but also good elasticity. PA endows these scaffolds with controllable biodegradation and anti-calcification and antioxidant activities. TEM discovered the co-existence of two types of fibrils with distinctly different arrangement patterns, explaining the contribution of KGM macromolecules to elasticity generation. The in vivo variations of Col/KGM/PA implants are visualized in real-time by magnetic resonance imaging (MRI). Moreover, a quantitative technique of MRI T₂-mapping combined with histology is designed to visualize the in vivo biodegradation mechanism of layer-by-layer erosion for these hydrogels. Simultaneously, three different relationships between the respective processes of in vivo degradation and in vivo dehydration of these controlled hydrogel implants were clearly revealed by this technique. Such a designed Col/KGM/PA composite hydrogel realizes the essential integration of good biocompatibility, controllable biodegradation and improved mechanical properties for developing a desired scaffold material for tissue engineering applications.

Construction and evaluation of fibrillar composite hydrogel of collagen/konjac glucomannan for potential biomedical applications

Konjac glucomannan (KGM) is recognized as a safe material for its health-promoting benefits and thus widely used in various fields including pharmaceutical industry. In recent decades, the combination of collagen and KGM attracts more attentions for biomedical purpose, especially the hybrid films of collagen–KGM or collagen–KGM–polysaccharide. In this study, to further and deeply develop the intrinsic values of both collagen and KGM as biomaterials, a novel kind of composite hydrogel comprising collagen and KGM at a certain ratio was fabricated under mild conditions via fibrillogenesis process of the aqueous blends of collagen and KGM that experienced deacetylation simultaneously. The chemical composition, microcosmic architectures, swelling behavior, biodegradation and dynamic mechanic properties of such resulted composite hydrogels were systematically investigated. Biologic experiments, including cell culture in vitro and hypodermic implantation in vivo, were also conducted on these collagen/KGM composite hydrogels to evaluate their biologic performances. The relevant results prove that, based on collagen self-assembly behavior, this synthesis strategy is efficient to construct a composite hydrogel of collagen/KGM with improved mechanical properties, biodegradability, excellent biocompatibility and bioactivity, which are promising for potential biomedical applications such as tissue engineering and regenerative medicine.

Preparation and characterisation of a novel hydrogel based on Auricularia polytricha β-glucan and its bio-release property for vitamin B12 delivery

BACKGROUND

This study investigates a novel hydrogel synthesis method and its bio-release property. This hydrogel, with a three-dimensional network structure based on Auricularia polytricha β-glucan, was characterised by means of Fourier transform infrared spectroscopy, ¹ H NMR and scanning electron microscopy. Vitamin B₁₂ (VB₁₂ , cobalamin) as a hydrophilic functional food component was entrapped into these hydrogels. The in vitro release profile of VB₁₂ was established in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).

RESULTS

The results showed that the hydrogel had medium pore size from 30 to 300 µm, and the swelling ratio increased with the degree of substitution. The hydrogel demonstrated good stability in SGF and bio-release capability in SIF for VB₁₂ . The accumulated release rate is about 80% in SIF and below 20% in SGF, which indicated the significant different release property in stomach and intestine.

CONCLUSION

The Auricularia polytricha β-glucan-based hydrogel has a good swelling ratio, pepsin stability and pancrelipase-catalysed biodegradation property. The bio-release rate is significantly different in SIF and SGF, which indicated that this hydrogel could be a good intestinal target carrier of VB₁₂ . © 2017 Society of Chemical Industry.

A Review on Konjac Glucomannan Gels: Microstructure and Application

Konjac glucomannan (KGM) has attracted extensive attention because of its biodegradable, non-toxic, harmless, and biocompatible features. Its gelation performance is one of its most significant characteristics and enables wide applications of KGM gels in food, chemical, pharmaceutical, materials, and other fields. Herein, different preparation methods of KGM gels and their microstructures were reviewed. In addition, KGM applications have been theoretically modeled for future uses.

A green porous solid carbon source supports denitrification in low C/N salinity wastewater

A green porous composite, the nitrate removal rate of which could reach 98.8% on the first day of denitrification.

Konjac glucomannan, a promising polysaccharide of Amorphophallus konjac K. Koch in health care

In recent year, konjac glucomannan (KGM) has attracted more attention due to its non-harmful and non-toxic properties, good biocompatibility, biodegradability and hydrophilic ability. Moreover, KGM and their derivatives have several importances in the multidirectional research areas such as nutritional, biotechnological and fine chemical fields. In the previous article, we have reviewed the nutritional aspects of KGM covering the various aspects of functional foods, food additives and their derivatives. This review aims at highlighting the diverse biomedical research conducted on KGM in the past ten years, covering therapies for anti-obesity, regulation in lipid metabolism, laxative effect, anti-diabetic, anti-inflammatory, prebiotic to wound dressing applications. Moreover, this review deals with global health aspects of KGM and the disparate health related factors associated with diseases and their control measures.

Preparation and characterization of a novel superabsorbent of konjac glucomannan-poly(acrylic acid) with trimethylolpropane trimethacrylate cross-linker

A novel superabsorbent was prepared by the solution polymerization of partially neutralized acrylic acid onto konjac glucomannan using potassium persulfate as a free radical initiator and trimethylolpropane trimethacrylate as a crosslinking agent.

Two natural glucomannan polymers, from Konjac and Bletilla, as bioactive materials for pharmaceutical applications

Next-generation biomaterials are expected to possess both desirable mechanical features and unique biological functions. Recently, two plant-derived glucomannans (GMs)-Konjac glucomannan (KGM) and the polysaccharide of Bletilla striata (BSP)-have emerged as new sources for development of biomaterials. They have been fabricated into drug delivery vehicles and wound healing dressings in varying shapes and sizes, and demonstrated strong gelling properties, high biocompatibility and remarkable convenience for processing and modification. Notably, they demonstrate bioactivities such as response to enzymes produced in special biological niches and/or affinity for carbohydrate receptors on specific cells. All these mechanical and biological advantages suggest these two GMs have great potential for future development and broader application in various biomedical and pharmaceutical fields.

Synthesis and characterization of well-defined PAA–PEG multi-responsive hydrogels by ATRP and click chemistry

Well-defined multi-responsive PAA–PEG hydrogels exhibit a unique swelling property at different pH and Ca²⁺ secondary crosslinking, and can potentially be used as stimuli responsive biomaterials.

Preparation and In Vitro Evaluation of Carboxymethyl Konjac Glucomannan Coated 5-Aminosalicylic Acid Tablets for Colonic Delivery

Konjac Glucomannan(KGM) was denatured by Carboxylmethylation to prepare Carboxymethyl konjac glucomannan(CMKGM) as coating material of 5-aminosalicylic acid(5-ASA) tablets. The 5-ASA release properties of the tablets were measured in vitro in the gastrointestinal tract simulation environment and in buffer solutions with β-mannase of pH 6.8 at 37 ± 0.5 degrees. The properties of the CMKGM were analyzed by FTIR spectra, viscosity measurement and swelling measurement. The integrality of the 5-ASA was investigated by ultraviolet spectrometry. The viscosity and swelling showed that CMKGM has lower swelling and lower viscosity compared to KGM. 5-ASA was released least in stimulating gastric environment and in pH 6.8 phosphate buffers,while the preparation was fast released in pH 6.8 phosphate buffers with β-mannase. The preparation was released 14% after 4 hours in pH 6.8 phosphate buffers , at the same time the preparation in pH 6.8 phosphate buffers with 0.2u ml-1 β-mannase was released 97% in 12 hours.The results suggested that CMKGM may be a useful carrier of 5 –ASA for colon-specific delivery. It has a potential use for advanced controlled release.