Starch Hydrogels Research Articles

Synthesis of PVA/corn starch hydrogel polymer electrolytes for supercapacitors

Synthesis of PVA/corn starch hydrogel polymer electrolytes for supercapacitors

Removal-Free and Multicellular Suspension Bath-Based 3D Bioprinting.

Suspension bath-based 3D bioprinting (SUB3BP) is effective in creating engineered vascular structures. The transfer of oxygen and nutrients via engineered vascular networks is necessary for tissue or organ survival and integration following transplantation. Existing SUB3BP techniques face challenges in fabricating hierarchical structures with multicellular organization, including issues related to suspension bath removal, restricted material choices, and low accuracy. A next-generation SUB3BP technique that is removal-free and multicellular is presented. A simple, storable, stable, and scalable starch hydrogel design leverages the diverse spectrum of hydrogels available for use in SUB3BP. Starch granules (8.1µm) create vascular structures with minimal surface roughness (2.5µm) that simulate more natural vessel walls compared to prior research. The development of cells and organoids, as well as the bioprinting of multicellular skin models with vasculature, demonstrates that starch suspension baths eliminate the removal process and have the potential for fabricating artificial tissue with a hierarchical structure and multicellular distribution.

Development of Slow-Release Fertilizers with Function of Water Retention Using Eco-Friendly Starch Hydrogels

Over the past two decades, the development and commercialization of slow-release fertilizers (SRFs) have significantly advanced, with the primary aim of mitigating environmental issues associated with excessive fertilizer use. A range of methodologies, including chemical and physical reactions, incorporation into carriers with porous and layered structures, and coating techniques, have been explored and refined. On the other hand, global challenges such as drought and desertification further underscore the need for SRFs that not only control nutrient release but also improve soil moisture retention. This paper reviews the development and application of eco-friendly starch hydrogels as fertilizer carriers and water retention for SRFs, particularly starch-based superabsorbent polymers (SAPs) produced through grafting copolymerization with acrylamide. This review explores both scientific issues, such as the microstructures and releasing mechanisms of SAPs, and technical development, involving copolymerization technologies, multi-initialization processes, methods of loading fertilizer into hydrogel, etc. Starch, as both a biodegradable and renewable carbohydrate polymer, offers distinct advantages due to its excellent chemical stability and high reactivity. The fabrication techniques of SAPs have been developed from traditional batch polymerization in aqueous solutions to more efficient, solvent-free reactive extrusion. The benefits of SRFs based on SAPs encompass enhanced soil aeration, the prevention of soil deterioration, the minimization of water evaporation, environmental pollution control, reduction in plant mortality, and prolonged nutrient retention within soil. In this review, we summarize the current progress, identify limitations in existing technologies, and propose future research directions to further enhance the performance of starch-based SRFs.

Development and evaluation of a novel margarine using starch hydrogel combined edible wax oleogel bigels

With heightened health awareness and regulatory guidelines, consumer preferences have shifted towards low/no saturated fat food products. Bigel has emerged as a viable solution for replacing saturated fat. In this study, a system based on bigel was developed using a potato starch-based hydrogel and a walnut oil/candelilla wax-based oleogel, and its quality characteristics including sensory properties, texture, rheology, crystal structure, solid fat content (SFC), and distribution uniformity of bigel were evaluated. The results indicated that the optimum ratio of oleogel (oil/wax=25) to hydrogel (distilled water/starch=30) for the prepared bigel-based margarine was 2:1 (w/w). The melting point of the bigel-based margarine ranged from 36.23±1.966 °C to 44.53±0.503 °C, with good plasticity, hardness, good thixotropy recovery and viscosity properties. The content of SFC was lower than 4%, the major crystal types were β and β' polycrystalline and possessed a good homogeneity. Generally, the preparation of nutritious and healthy margarine based on bigel is practicable. This research may provide a theoretical basis and also focus on the practical development and application of novel lower-temperature spreadable margarines.

Obtaining and characterization of natural extracts from mango (Mangifera Indica) peel and its effect on the rheological behavior in new mango kernel starch hydrogels

Hydrogels based on natural polymers have aroused interest from the scientific community. The aim of this investigation was to obtain natural extracts from mango peels and to evaluate their addition (1, 3, and 5%) on the rheological behavior of mango starch hydrogels. The total phenolic content, antioxidant activities, and phenolic acid profile of the natural extracts were evaluated. The viscoelastic and thixotropic behavior of hydrogels with the addition of natural extracts was evaluated. The total phenol content and antioxidant activity of the extracts increased significantly (p<0.05) with the variation of the ethanol-water ratio; the phenolic acid profile showed the contain of p-coumaric, ellagic, ferulic, chlorogenic acids, epicatechein, catechin, querecetin, and mangiferin. The viscoelastic behavior of the hydrogels showed that the storage modulus G′ is larger than the loss modulus G′′ indicating a viscoelastic solid behavior. The addition of extract improved the thermal stability of the hydrogels. 1% of the extracts increase viscoelastic and thixotropic properties, while concentrations of 3 to 5% decreased. The recovery percentage (%Re) decreases at concentrations from 0% to 1% of natural extracts, however, at concentrations from 3% to 5% increased.

Effect of microwave irradiation and conventional heating on high pressure modified white finger millet starch hydrogel properties

High pressure modified (200 MPa and 400 MPa for 10 min) white finger millet starch hydrogels were prepared with three starch concentrations (12 %, 15 % and 18 % (w/v)), by conventional heat treatment (75 °C for 12 min) and microwave treatment (50 s at 900 W, surface temperature 75 °C). The prepared hydrogels were compared to native white finger starch hydrogels for understanding the effect of modification as well as the gel synthesis method. Effect of the storage period on physical stability was evaluated for ten days by evaluating weight loss, water activity, and color. The whiteness index of the prepared hydrogel intensified during the storage period, and water activity was reduced (0.99–0.976). While stored at 4 °C, the hydrogel weight decreased due to moisture migration. The results emphasize that treatment conditions, starch modification, and concentration significantly affected water absorption. The maximum gel strength was identified for conventional heat-induced 400 MPa high-pressure modified hydrogel stored for ten days. 1H NMR relaxation time showed microwave-induced gel synthesis had a shorter relaxation time. The gel microstructure helped to correlate the swelling and gel strength increment in the modified gel sample, as it had a higher wall thickness and a smaller pore size than heat-induced hydrogels. These findings help to conclude high pressure modified white finger millet starch hydrogel synthesised by microwave irradiation can be alternative to conventional heat gelatinisation method.

Insights in the adsorption of eco-friendly starch hydrogel

Insights in the adsorption of eco-friendly starch hydrogel

Separation studies of 60Co (II) and 134Cs (I) radionuclides from aqueous solution using starch-grafted citric acid-acrylamide/magnesia hydrogel

Abstract In this study, three starch hydrogels composite prepared using different ratios of starch, citric acid, acrylamide, and MgO nanoparticles (referred to as St1-g-(CA-AM), St2-g-(CA-AM), and St3-g-(CA-AM) MgO). These materials were assessed using FT-IR, SEM, and EDX. The adsorption of 134Cs(I) and 60Co (II) onto these materials studied using radiometric analysis. The investigation focused on how temperature, contact duration, initial metal ion concentration, and pH of the solution affected the sorption efficiency. It is found that a pH value of 7 optimized the adsorption reaction, reaching equilibrium after 40 minutes. The kinetics of the adsorption followed a pseudo-second order model. The Langmuir model adequately explained the sorption mechanism, supported by the analysis of isotherm models. The monolayer adsorption capacities for 60Co (II) and 134Cs (I) were 113.38 and 100.2 mg g−1, respectively. The thermodynamic study indicated that the sorption process is both endothermic and spontaneous.

High specific surface area carbon aerogel derived from starch for methylene blue adsorption and supercapacitors

Starch based carbon aerogel has attracted significant attention due to the wide source, environmental friendliness and low price of raw materials. Here, starch based carbon aerogel was fabricated by graft reaction and cross-linking reaction of starch. The network structure of starch hydrogel was optimized through graft and cross-linking reaction. After freeze drying and high temperature carbonization, the obtained carbon aerogel that carbonized at 800 °C showed a specific surface area of 1508 m2·g−1 without activation which is far higher than that of other unactivated carbon aerogels. The starch based carbon aerogel carbonized at 800 °C exhibited superior methylene blue adsorption ability with a maximum adsorption capacity of 963.5 mg·g−1 as a result of its rich surface functional groups, high specific surface area, and reasonable pore size distribution. Furthermore, the carbon aerogel carbonized at 700 °C exhibited excellent electrochemical performance with a specific capacitance of 180.1 F·g−1 at a current density of 1 A·g−1as electrode materials for supercapacitors. Overall, this work provides a new method to prepare high performance starch based carbon aerogel.

Non-toxic, Printable Starch Hydrogel Composite with Surface Functionalized Silver Nanoparticles Having Wide-Spectrum Antimicrobial Property

Non-toxic, Printable Starch Hydrogel Composite with Surface Functionalized Silver Nanoparticles Having Wide-Spectrum Antimicrobial Property

The Development of a Bacterial Nanocellulose/Cationic Starch Hydrogel for the Production of Sustainable 3D-Printed Packaging Foils.

Polymers have become an important part of everyday life, but most of the polymers currently used are petroleum-based. This poses an environmental problem, especially with respect to products that are quickly discarded. For this reason, current packaging development focuses on sustainable materials as an alternative to synthetic ones. Nanocellulose, a relatively new material derived from cellulose, has unique properties such as high strength, low density, high surface area, and good barrier properties, making it popular in various applications. Additionally, 3D printing technologies have become an important part of industrial and commercial processes, enabling the realization of innovative ideas and functionalities. The main aim of this research was to develop a hydrogel of bacterial nanocellulose with suitable rheological properties for the 3D printing of polymer foils. Three variations of bacterial nanocellulose hydrogel differing in ratios of bacterial nanocellulose to cationic starch were produced. The rheological studies confirmed the suitability of the hydrogels for 3D printing. Foils were successfully 3D-printed using a modified 3D printer. The physical-mechanical, surface, and optical properties of the foils were determined. All foils were homogeneous with adequate mechanical properties. The 3D-printed foils with the highest amount of cationic starch were the most homogeneous and transparent and, despite their rigidity, very strong. All foils were semi-transparent, had a non-glossy surface, and retained poor water wettability.

Synthesis of AgO/CuO/PVA/starch hydrogel by casting method and characterizations to safely overcome skin infections: A possible application in wound healing as a dressing

Wounds are frequently developing resistance to a conventional wound dressing. Therefore, bioactive and biodegradable hydrogel membranes that could serve as wound dressing could be a legitimate strategy for wound healing, Herein, a chemically cross-linking method was used to synthesize polyvinyl alcohol (PVA)/starch hydrogel, which was subsequently loaded, via the solution casting method, with Silver oxide/Copper oxide (AgO/CuO) nanocomposite (NC) tested at various concentrations (i.e., 0.1, 0.3, 0.5, and 0.7 g/L). The prepared hydrogels were physically characterized through standard techniques, including Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Fourier Transform Infrared Radiation (FTIR). The influence of the different AgO/CuO NC concentrations was analyzed through tensile strength, swelling behavior, moisture retention capability (MRC), gel fraction, and water vapor transport (WVT) analyses. The relative toxicity (patch test) of hydrogel membranes was also evaluated on the human skin. The antibacterial potential was investigated against common skin pathogens (i.e., Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Candida albicans) through the disc diffusion method (DDM). SEM images depicted AgO/CuO/PVA/starch hydrogel membranes as shiny, smooth, and dense. XRD analysis revealed the purity and crystallinity of these hydrogels. FTIR data determined the functional chemical groups and confirmed the successful preparation of AgO/CuO/PVA/starch hydrogels. The increased concentrations of AgO/CuO NC in PVA/starch hydrogel membrane has boosted the tensile strength, swelling behavior, and MRC of the hydrogel membranes, whereas the WVT and gel fraction were decreased. Also, the AgO/CuO/PVA/starch hydrogel exerted enhanced antimicrobial activity against all the tested skin pathogens and no toxicity was observed when applied to the human skin. Taken together, the prepared AgO/CuO/PVA/starch hydrogel is a promising approach for wound dressing due to its desirable mechanical properties, safety, and its excellent barrier against skin pathogen penetration and infection.

Utilizing Synchrotron-Based X-ray Micro-Computed Tomography to Visualize the Microscopic Structure of Starch Hydrogels In Situ.

This study aimed to visualize the microstructures of starch hydrogels using synchrotron-based X-ray micro-computed tomography (μCT). Waxy maize starch (WMS, 3.3% amylose, db), pea starch (PS, 40.3% amylose), and high-amylose maize starch (HMS, 63.6% amylose) were cooked at 95 and 140 °C to prepare starch hydrogels. WMS and HMS failed to form a gel after 95 °C cooking and storage, while PS developed a firm gel. At 140 °C cooking, HMS of a high amylose nature was fully gelatinized and generated a rigid gel with the highest strength. Both scanning electron microscopy (SEM) and μCT revealed the unique structural features of various starch hydrogels/pastes prepared at different temperatures, which were greatly affected by the degree of swelling and dispersity of the starches. As a nondestructive method, μCT showed certain advantages over SEM, including minimal shrinkage of the hydrogels, relatively simple sample preparation, and allowing for three-dimensional reconstruction of the hydrogel microstructure. This study indicated that synchrotron-based μCT could be a useful technique in visualizing biopolymer-based hydrogels.

Optimization of method for cross-section hydrogels preparation using high-pressure freezing.

High-pressure water freeze fracturing is a method for preparing water-containing samples such as hydrogels for scanning electron microscopy (SEM), in which a sample is placed in a divisible pressure vessel, filled with water, sealed, frozen with liquid nitrogen and then vacuum dried after the vessel is divided. The pressure (∼200 MPa) generated by the phase transition from water to ice is expected to inhibit ice crystal formation that causes large deformation of microstructure in the sample. To maximize the useable sample size, where SEM observation is not affected by ice crystal growth, preparation conditions including the size of pressure vessel were examined in this work. Using pressure vessels 8.0 mm, 5.5 mm and 4.5 mm in diameter, agarose gel, gelatin gel, wheat starch hydrogel, wheat flour noodle and cellulose hydrogel were used to prepare SEM samples. With agarose gel, an area of 3.6 mm in diameter in the 5.5 mm vessel was achieved as the maximum size of the area observable without ice crystal growth. The observable size of other samples was comparable, except for gelatin gel. As a result, observation of the three-dimensional network structure of hydrogels could be performed over a wider range than with the conventional method without shredding or chemical treatment of the samples. Additionally, usability of agarose gel for sample support matrix in high-pressure water freeze fracturing was demonstrated.

Determination of Density of Starch Hydrogel Microspheres from Sedimentation Experiments Using Non-Stokes Drag Coefficient.

Sedimentation is an important property of colloidal systems that should be considered when designing pharmaceutical formulations. In pharmaceutical applications, sedimentation is normally described using Stokes' law, which assumes laminar flow of fluid. In this work we studied swelling and hydration of spherical cross-linked amorphous starch microspheres in pure water, solutions of sodium chloride, and in pH-adjusted aqueous solutions. We demonstrated that Reynolds numbers obtained in these experiments correspond to the transition regime between the laminar flow and the turbulent flow and, hence, expressions based on the non-Stokes drag coefficient should be used for calculations of sedimentation velocity from known density or for assessment of density from observed sedimentation velocity. The density of starch microparticles hydrated in water was about 1050 kg/m3, while densities obtained from experiment with other liquids were dependent on the liquids' densities. The data indicate that the swelling of the cross-linked starch microparticles as characterized by their densities is not sensitive to pH and salt concentration in the studied range of these parameters.

In vitro digestibility of rice and tapioca starch-based hydrogels produced by high-pressure processing (HPP)

The development of natural systems such as starch-based biopolymers and their applicability present a substantial challenge to the food industry, underscoring the critical need to extend the investigation to their digestibility. This study investigated the in vitro digestibility of rice and tapioca starch-based hydrogels, obtained by High-Pressure Processing (HPP) (600 MPa for 15 min) and by conventional thermal treatment (80 °C for 15 min) to assess the influence of HPP on starch digestibility as well as to identify the critical digestion steps. During in vitro digestion, disintegration, total hydrolysed starch, and starch nutritional fractions were determined. Results demonstrated that rice hydrogels underwent a higher disintegration extent and degree of starch hydrolysis with respect to tapioca hydrogels, being this more evident in HPP hydrogels. Both hydrogels were almost completely digested at the end of the digestion phases, with hydrolysed starch higher than 94% and 88% for rice and tapioca, respectively. HPP could represent a key technology to increase the digestibility of the resistant starch fraction of rice and tapioca starch hydrogels, increasing the potential applicability of these biopolymers.

Controlling the Porosity of Starch Hydrogels with Poly(Methyl Methacrylate) (PMMA) Beads

AbstractStarch is a natural, biodegradable polymer that can be used to prepare hydrogels with various applications in food, pharmacy, medicine, agriculture, etc. In this study, a method of preparation using poly(methyl methacrylate) (PMMA) beads to control the porosity of starch hydrogels is proposed. The hydrogels are crosslinked with trisodium trimetaphosphate and dried in a vacuum oven. Results show that increasing the amount of PMMA beads result in higher porosity hydrogels ranging from ≈35% for hydrogels where no PMMA beads are used to ≈88% for hydrogels where the mass ratio of PMMA beads to starch is 10:1. Higher porosity hydrogels have a higher equilibrium water content and swelling degree, but lower mechanical properties. All hydrogels have a low solubility (&lt;≈5%) and a high gel fraction (&gt;≈90%) percentage. Upon degradation in α‐amylase at 37 °C, low porosity hydrogels (prepare with 0:1 and 1:10 PMMA beads:starch) degrade within 30 min, while high porosity hydrogels (prepare with 1:1 and 10:1 PMMA beads:starch) degrade within 3 weeks. The release of a dye that is incorporated into the hydrogel walls follows similar kinetics. Therefore, the use of PMMA beads is an efficient method to control starch hydrogel's porosity and properties.

Preparation and Application of Zwitterion Modified Starch Catalyzed by HRP‐ACAC Binary System

AbstractEnzymatic modification, compared with traditional starch (St) chemical modification methods, avoids using toxic solvents and toxic catalysts. The horseradish peroxidase (HRP), being the most commonly employed natural green initiator, has found extensive application in starch grafting modification as a substitute for chemical initiators. HRP‐catalyzed grafting of starch with vinyl zwitterionic monomers has not been reported. Here, modified starch (St‐PSBMA) is first synthesized by grafting zwitterionic sulfobetaine [2‐(Methacryloyloxy)ethyl]dimethyl‐(3‐sulfopropyl) (SBMA) onto starch by HRP/Acetylacetone(ACAC) binary initiation system catalyzed. The modified starch‐based hydrogel is then prepared by the repeated freeze‐thaw method. Compared with native starch‐based hydrogels, which bind water molecules only through hydrogen bonding, the ability of modified starch‐based hydrogels to bind water molecules is enhanced by ionic solvation. The modified starch hydrogels also have excellent antiprotein adsorption and antibacterial properties due to the presence of a strong hydration layer. The modified starch‐based hydrogel also has excellent sensitivity and stability when used as a sensor for detecting joint motion. The binary HRP initiating system, employed in this study instead of the traditional three‐component HRP initiating system, offers a novel and promising approach for grafting modification of starch without the need for strong oxidant hydrogen peroxide.

The Potent Antimicrobial Spectrum of Patchouli: Systematic Review of Its Antifungal, Antibacterial, and Antiviral Properties

ntention towards natural essential oils from medicinal plants has increased rapidly over the past decade as these oils have antimicrobial and antioxidant properties against various chronic diseases. One essential oil source with antimicrobial properties is the essential oil from Pogostemon cablin (Blanco) Benth. This review aims to provide information on using patchouli oil as an antimicrobial against bacterial, fungal, and viral pathogens in the last five years. There were 37 articles found in the PUBMED database by June 15, 2023. After searching, 6 of them were duplicates. A total of 2 papers were inaccessible, 4 were not research articles, and five were excluded because they were irrelevant to the scope of this study. This review shows that research related to patchouli as an antimicrobial in the last five years involves Pogostemon cablin leaf samples as silver nanoparticle bioreductors. Patchouli oil is used in membrane, nanocomposite film, and starch hydrogel manufacturing. Patchouli oil is a prestigious antimicrobial agent because it can fight numerous pathogenic microbes from bacteria, fungi, and viruses.

Ionic conductive soluble starch hydrogels for biocompatible and anti-freezing wearable sensors

Hydrogel sensors have been widely researched for their good biocompatibility and mechanical properties similar to those of human skin, enabling the monitoring and transmission of a wide range of signals, thus promoting the development of flexible wearable electronic devices. However, long-term direct contact between hydrogel sensors and human skin can cause bacterial infection phenomena, and endowing hydrogel materials with antimicrobial properties is an important challenge in sensing applications. Here, an antimicrobial hydrogel was researched and explored via a freeze–thaw method introducing soluble starch, polyhexamethylene biguanide hydrochloride, glycerin, lithium chloride, and polyvinyl alcohol. The hydrogel expressed remarkable frost resistance, water retention, fatigue resistance, stability, sensitivity, responsiveness, electrical conductivity. The hydrogel exhibited an inhibitory loop resistant to Escherichia coli and Bacillus subtilis and emerged an inhibitory stability over 7 days. Simultaneously, the hydrogel expressed biocompatibility without tissue contamination, inflammation and other adverse phenomena under the skin of mice for 14 days. Furthermore, the hydrogel could record the signals of deformation during the process of the human motion. Therefore, the simple strategy is promising for medical fields including human motion detection, physiological signal recording and medical health detection.