Starch-based Hydrogels Research Articles

Adsorption behavior and mechanism of lead by starch/tobermorite composite hydrogel.

Tobermorite (TOB) is a synthetic inorganic mineral material with a montmorillonite-like layered structure that removes heavy metals from water, and its incorporation into starch-based hydrogels can optimize the stability and adsorption properties of the hydrogels; it can also significantly reduce the storage pressure of fly ash (FA) and reduce environmental pollution. This study utilized starch/tobemolite/acrylic acid (LR/TOB/AA) as the raw material, successfully synthesizing a starch-tobemolite composite hydrogel (LR-TOB/AA) using aqueous solution polymerization. The hydrogel exhibits excellent water absorption and retention capabilities, as well as a significant adsorption effect on Pb(II). The influence of adsorption duration, starting concentration, temperature, and hydrogel incorporation on Pb(II) adsorption was examined by intermittent adsorption experiments. The maximal adsorption capacity of Pb(II) was 900.25 mg/g, surpassing the majority of reported hydrogel adsorbents, as determined by Langmuir isothermal adsorption model fitting. Following five adsorption-desorption cycles, the hydrogel's adsorption of Pb(II) persisted above 90 %.

A multifunctional and tough lotus root starch-based bio-photonic hydrogel for stretchable fabric pattern color change and water rewriting.

Photonic crystal hydrogels (PCHs) are innovative materials that translate imperceptible deformations and humidity changes into visible colors, broadening the applications of photonics in bioengineering and smart materials. To overcome poor mechanical properties of traditional PCHs limited by weak intermolecular forces, we designed a PCH with a dual-network framework comprising N-isopropylacrylamide-co-acrylamide (NIPAM-co-AM) and biomass lotus root starch (LR). Since LR is rich in hydroxyl groups, it can undergo molecular linkage entanglement with the NIPAM-co-AM hydrogel matrix, forming hydrogen bonds that significantly enhance the mechanical properties of the PCH. We have prepared PCH films capable of conveying multidimensional information about the extent and distribution of transient deformation by encapsulating magnetic photonic crystal microspheres (MPCMs) within a hydrogel matrix. The PCH films were found to have ultrafast response time (< 10 s), full-color tunable range, high spatial resolution, excellent mechanical toughness (tensile up to 0.17 MPa) and sensitivity (2.52 nm %-1), and were able to sense relative humidity (RH) from 11 % to 98 %. Equipped with a dynamically reconfigurable lattice, this dual-responsive (tensile/humidity) PCH not only facilitates the creation of water-rewritable photonic films but also holds promise for integration into structural color elastic fabrics, thereby presenting novel prospects for smart textile applications.

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.

Starch/ionic liquid/hydrophobic association hydrogel with high stretchability, fatigue resistance, self-recovery and conductivity for sensitive wireless wearable sensors

Conductive hydrogels have been widely used in wearable electronics due to their flexible, conductive and adjustable properties. With ever-growing demand for sustainable and biocompatible sensing materials, biopolymer-based hydrogels have drawn significant attention. Among them, starch-based hydrogels have a great potential for wearable electronics. However, it remains challenging to develop multifunctional starch-based hydrogels with high stretchability, good conductivity, excellent durability and high sensitivity. Herein, amylopectin and ionic liquid were introduced into a hydrophobic association hydrogel to endow it with versatility. Benefiting from the synergistic effect of amylopectin and ionic liquid, the hydrogel exhibited excellent mechanical properties (the elongation of 2540 % with a Young's modulus of 12.0 kPa and a toughness of 1.3 MJ·m−3), self-recovery, good electrical properties (a conductivity of 1.8 S·m−1 and electrical self-healing), high sensitivity (gauge factor up to 26.85) and excellent durability (5850 cycles). The above properties of the hydrogel were closely correlated to its internal structure from hydrophobic association, H-bonding and electrostatic interaction, and can be regulated by changing the component contents. A wireless wearable sensor based on the hydrogel realized accurate and stable monitoring of joint motions and expression changes. This work demonstrates a kind of promising biopolymer-based materials as candidates for high-performance flexible wearable sensors.

Effects of the Amylose/Amylopectin Ratio of Starch on Borax-Crosslinked Hydrogels.

Herein, we simultaneously prepared borax-crosslinked starch-based hydrogels with enhanced mechanical properties and self-healing ability via a simple one-pot method. The focus of this work is to study the effects of the amylose/amylopectin ratio of starch on the grafting reactions and the performance of the resulting borax-crosslinked hydrogels. An increase in the amylose/ amylopectin ratio increased the gel fraction and grafting ratio but decreased the swelling ratio and pore diameter. Compared with hydrogels prepared from low-amylose starches, hydrogels prepared from high-amylose starches showed pronouncedly increased network strength, and the maximum storage modulus increased by 8.54 times because unbranched amylose offered more hydroxyl groups to form dynamic borate ester bonds with borate ions and intermolecular hydrogen bonds, leading to an enhanced crosslink density. In addition, all the hydrogels exhibited a uniformly interconnected network structure. Furthermore, owing to the dynamic borate ester bonds and hydrogen bonds, the hydrogel exhibited excellent recovery behavior under continuous step strain, and it also showed thermal responsiveness.

Optimizing modified natural rubber in starch-based hydrogels: A cost-effective approach for high-performance sustainable slow-release fertilizer coatings

Effective compatibility between natural rubber (NR) and cassava starch (CSt) is crucial for enhancing the water swelling and retention properties of CSt/NR-based hydrogels. In this study, NR was modified by grafting glycidyl methacrylate (NR-g-GMA, NRG) at 3, 6, and 9 parts per hundred rubber (phr) for blending with CSt. Subsequently, CSt was grafted with acrylamide (AM), crosslinked with N,N′ − methylene-bis-acrylamide (MBA), and interpenetrated with NRG to produce CSt-g-PAM/NRG hydrogels. The resulting CSt-g-PAM/NRGx (x = phr of GMA) hydrogels were characterized using FTIR, XRD, TGA, tensile testing, and water swelling measurements. Results revealed that CSt-g-PAM/NRG3 exhibited the highest equilibrium water swelling at 3300 %, surpassing CSt-g-PAM/NR (1430 %) and demonstrated the highest mechanical strength (0.92 MPa), desirable biodegradability (69 % at 30 days), and good water retention. These properties are attributed to the superior compatibility and stronger interactions between NRG and the CSt-g-PAM networks. Additionally, the WUHNRG3 (urea coated with CSt-g-PAM/NRG3 and wax layers) fertilizer demonstrated good biosafety, an acceptable slow-release rate (50.26 % at 30 days), and effectively promoted the growth of chili plants at a reasonable cost. This study demonstrates that modifying NR with optimal GMA content provides an effective CSt-g-PAM/NRG coating membrane, suitable for sustainable slow-release fertilizers and green agricultural practices.

Synthesis and Adsorption of Alginate and Starch-Based Hydrogels for Cationic Dye from Aqueous Solution: Thermodynamic and Isotherm Modeling Non-linear

Synthesis and Adsorption of Alginate and Starch-Based Hydrogels for Cationic Dye from Aqueous Solution: Thermodynamic and Isotherm Modeling Non-linear

A Comprehensive Review on Starch-Based Hydrogels: From Tradition to Innovation, Opportunities, and Drawbacks.

Natural hydrogels based on renewable and inexpensive sources, such as starch, represent an interesting group of biopolymeric materials with a growing range of applications in the biomedical, cosmeceutical, and food sectors. Starch-based hydrogels have traditionally been produced using different processes based on chemical or physical methods. However, the long processing times, high energy consumption, and safety issues related to the synthesis of these materials, mostly causing severe environmental damage, have been identified as the main limitations for their further exploitation. Therefore, the main scientific challenge for research groups is the development of reliable and sustainable processing methods to reduce the environmental footprint, as well as investigating new low-cost sources of starches and individuating appropriate formulations to produce stable hydrogel-based products. In the last decade, the possibility of physically modifying natural polysaccharides, such as starches, using green or sustainable processing methods has mostly been based on nonthermal technologies including high-pressure processing (HPP). It has been demonstrated that the latter exerts an important role in improving the physicochemical and techno-functional properties of starches. However, as for surveys in the literature, research activities have been devoted to understanding the effects of physical pre-treatments via high-pressure processing (HPP) on starch structural modifications, more so than elucidating its role and capacity for the rapid formation of stable and highly structured starch-based hydrogels with promising functionality and stability, utilizing more sustainable and eco-friendly processing conditions. Therefore, the present review addresses the recent advancements in knowledge on the production of sustainable starch-based hydrogels utilizing HPP as an innovative and clean-label preparation method. Additionally, this manuscript has the ambition to give an updated overview of starch-based hydrogels considering the different types of structures available, and the recent applications are proposed as well to critically analyze the main perspectives and technological challenges for the future exploitation of these novel structures.

Effect of active carbonyl-carboxyl ratio on dynamic Schiff base crosslinking and its modulation of high-performance oxidized starch-chitosan hydrogel by hot extrusion 3D printing

The quest to develop 3D starch-based printing hydrogels for the controlled release of active substances with excellent mechanical and printing properties has gained significant attention. This work introduced a facile method based on crosslinking via Schiff base reaction for preparing bicomponent hydrogels. The method involved the utilization of customizable oxidized starch (OS) and chitosan (CS), enabling superior printing performance through the precise control of various active carbonyl-carboxyl ratios (ACR, 2:1, 1:1, and 2:3, respectively) of OS. OS-CS hydrogel (OSC) with an ACR level of 2:1 (OS-2-y%CS) underwent rearrangement during printing environment, fostering increased Schiff base reaction with a higher crosslinking degree and robust high structural recovery (>95 %). However, with decreasing ACR levels (from 2:1 to 2:3), the printing performance and mechanical strength of printed OSC (POSC) declined due to lower Schiff base bonds and increased phase separation. Compared with printed OS, POS-2-2%CS exhibited a remarkable 1250.52 % increase in tensile strength and a substantial 2424.71 % boost in compressive strength, enhanced shape fidelity and notable self-healing properties. Moreover, POS-2-2%CS exhibited stable diffusive drug release, showing potential application in the pH-responsive release of active substances. Overall, controlling the active carbonyl-carboxyl ratios provided an efficient and manageable approach for preparing high-performance 3D-printed hydrogels.

Synthesis and Characterization of Triticale Starch-Based Hydrogel for pH Responsive Controlled Diffusion.

Considering the FAO perspectives for agriculture toward 2030, many natural sources will be no longer profitable for the synthesis of many biomaterials. Triticale (X Triticosecale Wittmack) is a cereal crop synthesized to withstand those marginal conditions; however, it is primarily used as fodder worldwide. We reported for the first time the synthesis of a natural anionic hydrogel with gastrointestinal pH stimulus-response as a new alternative of smart material, based on Eronga triticale starch as sustainable biomass, using citrate (pK a ∼3.1, 4.7, and 6.4) as cross-linking agent. The scanning electron microscopy and X-ray diffraction exhibited A and B-type starch granules, and semicrystallinity A-type. The presence of the anionic sensing group (COOH) was verified by infrared spectroscopy, the interactions by hydrogen bonds between starch and glycerol and esterification between starch and citric acid were identified by 1H NMR spectra, and through thermal analysis hydrogels exhibited four endothermic curves (179-319 °C, ∼0.711-39 kJ/mol E a). The results showed that the slight addition of glycerol increases the thermal stability, but a higher amount of glycerol decreases the intermolecular forces affecting the thermal stability contrary, the mechanical properties could be benefited. The rheological analyses showed viscoelastic tendency (G' > G″) with high stability (Tanδ < 1) in frequency, time, and strain sweeps. Gastrointestinal pH sensitivity (∼2-7.8) was verified (α ≤ 0.01) following Fick's diffusive parameters, which resulted in a tendency to gradually release BSA with increasing pH ∼3-7 by anomalous and case-II diffusion, showing greater release at pH ∼7.8/3.5 h (80-96%). We aim to expand the biomaterials area focusing on triticale starch due to its limited reported investigations, low-cost, green modification, and its rheological performance as plastic.

Highly Tough, Freeze-Resistant, Sensitive, and Recyclable Starch-based Multifunctional Hydrogel Flexible Wearable Sensor for Human Motion Monitoring

Highly Tough, Freeze-Resistant, Sensitive, and Recyclable Starch-based Multifunctional Hydrogel Flexible Wearable Sensor for Human Motion Monitoring

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.

Green, tough, and heat-resistant: A GDL-induced strategy for starch-alginate hydrogels

Hydrogels fabricated by non-covalent interaction garnered significant attention for their eco-friendly and robust mechanical attributes, and are often used in food, medicine and other fields. Although starch-alginate hydrogels exhibit high adhesion and are environmentally sustainable, their applications are limited due to their low elasticity and hardness. Addressing this challenge, we introduce a solvent-induced strategy using glucolactone (GDL) to fabricate hydrogels with enhanced strength and thermal resilience. Utilizing corn starch with varying amylose contents, sodium alginate and calcium carbonate to prepare a double network structure. This GDL-induced hydrogel outperforms most previous starch-based hydrogels in mechanical robustness and thermal stability. Typical starch-alginate hydrogel had a homogeneous network structure and exhibited a high tensile stress of 407.57 KPa, and a high enthalpy value of 1857.67 J/g. This investigation furnishes a facile yet effective method for the synthesis of hydrogels with superior mechanical and thermal properties, thereby broadening the design landscape for starch-based hydrogels.

Formulation of double nanoemulsions based on pH-sensitive carboxymethyl cellulose /Starch copper doped carbon quantum dots for quercetin controlled release

Nanocomposite Hydrogels are versatile and adaptable in drug delivery, suitable for various administrations. They offer prolonged and regulated drug release which makes them valuable in targeting cancer treatments. This study used the water/oil/water approach to construct a drug nanocarrier. It encapsulated hazelnut oil, serving as a protective and organic membrane that enveloped the nanocarrier and regulated drug release. Quercetin (QC), a potent flavonoid with potential therapeutic applications, faces challenges due to its hydrophobic nature and poor solubility. This approach presents a novel approach to enhance QC's solubility and stability by integrating it with copper carbon quantum dots (Cu-CQDs) into a pH-sensitive carboxymethyl cellulose (CMC) and starch-based hydrogel nanocomposite. This system aims to improve QC delivery while minimizing adverse effects. The nanocomposite exhibited exceptional drug loading and encapsulation efficiencies of 47.00 % ± 0.45 and 86.25 % ± 0.75, respectively, ranking among the top-reported values for similar systems. Fourier-transform infrared spectroscopy (FTIR) was used to examine molecular interactions. X-ray diffraction (XRD) assessment demonstrated the presence of components beneficial for drug solubility enhancement at 2Θ = 17–24°, where QC's crystalline peaks are absent from the CMC/Starch/Cu-CQDs@QC XRD pattern. A particle size of 151.57 ± 37 nm is optimized for selectively targeting cancer cells, minimizing interaction with healthy cells, as revealed through DLS assessment. Morphological characteristics analyzed by FE-SEM support this observation as well. Zeta potential measurement (+38.8 mV) highlights nanocarrier stability. CMC/Starch/Cu-CQDs@QC displayed remarkable cytotoxicity against cancerous cells, reducing U87-MG cell viability to 48 % while maintaining high cell viability (92 %) for normal L929 cells. These results emphasize the promise of this nanocomposite as a QC drug delivery system by indicating improved anticancer efficacy with fewer adverse effects.

Hydrothermal extraction of antioxidants from Camellia sinensis fruit husks: Experimental design in the development of enriched gels

The phenolic and saccharidic fractions from Camellia sinensis seed husks were extracted under selected conditions of hydrothermal treatment and further concentrated with membranes and nonionic polymeric resins. The fraction extracted heating up to 160 °C contained 30 % oligomers, being concentrated by ultrafiltration up to 1.4 times. The waste solids were further processed up to 220 °C to extract an additional phenolic fraction. Both the permeate from ultrafiltration membranes and the extract obtained in the second hydrothermal stage were concentrated by nanofiltration and by resin adsorption (SP-700). The refined extracts after elution in ethanol contained 75 % and 50 % phenolics, respectively and exhibited antiradical properties comparable to synthetic antioxidants. The xylooligosaccharide (XOS) and the phenolic (Ph) containing fractions were used to formulate starch-based hydrogels and a Box-Behnken experimental design was used to optimize the relative content of each fraction and the gelling temperature to maximize the rheological and color parameters of the hydrogels. Evaluating the multiple response of the effect of the formulation conditions on the viscoelastic behavior through tan δ and the luminosity of the gels through L*, the maximum values were observed for gels prepared in the absence of XOS and 29.8% of E160 at 63.5 °C.

Optimization of processing conditions of starch-based hydrogels produced by high-pressure processing (HPP) using response surface methodology

Introduction: This study aimed to determine the optimal processing conditions to produce stable starch-based hydrogels by high-pressure processing (HPP) via response surface methodology.Methods: The experiments were carried out with different starch suspensions, namely rice, corn, wheat, and tapioca starch, at a concentration in the range of 10%–40% w/w, processed at a pressure level of 600 MPa and holding times between 5 min and 15 min. Gel formation was assessed by determining the gelatinization extent and structuring level of the samples.Results and discussion: The results demonstrated that starch/water ratio and holding time had a significant impact on gel formation in HPP treatments. Various degrees of gelatinization were observed in the treated samples due to the water absorption capacity of the starch and the molecular interactions between water and starch occurring during gelatinization. Moreover, a highly structured hydrogel formed at starch concentrations higher than 25% (w/w), whereas when starch concentration was less than 20% (w/w) lower-structured hydrogels formed, as confirmed by the values of the efficiency index measured. Completely gelatinized, highly structured, and stable HPP hydrogels were obtained from starch solutions treated at the optimized processing conditions.

Green Starch-Based Hydrogels with Excellent Injectability, Self-Healing, Adhesion, Photothermal Effect, and Antibacterial Activity for Promoting Wound Healing.

Hydrogel materials have proven valuable in wound healing, but improving the safety of these hydrogels is still challenging. Therefore, designing multifunctional natural polymeric-based hydrogels with excellent mechanical properties to replace toxic or potentially risky, refractory chemical polymer-based hydrogels such as polyacrylamide and polyethylene glycol is of particular significance. Here, a green starch-based hydrogel (Starch@Ca/CGC hydrogel) with injectability, self-healing, and instant adhesion was constructed by coordination interaction, electrostatic interaction, and intramolecular and intermolecular hydrogen bonds. Therein, natural bioactive small molecules gallic acid (GA) and carvacrol (CA) were coordinated with metal ions by the ultrasonic-triggered self-assembly and ionic cross-linking codriven strategy to prepare Cu-gallic acid-carvacrol nanospheres (CGC NPs), which conferred the hydrogel with near-infrared light (NIR)-controlled CA release and photothermal synergistic sterilization properties, as well as antioxidant and anti-infection capabilities. More importantly, the multifunctional hydrogel platforms could completely cover an irregular wound shape to prevent secondary injury and significantly accelerate wound healing under NIR with more skin appendages like hair follicles and blood vessels appearing. Therefore, it is expected that this starch-based hydrogel could serve as a competitive multifunctional dressing in the biomedical field, including bacteria-derived wound infection and other tissue repair.

Polyelectrolyte composite hydrogels based on a derivative of functional dietary fiber for long-term gastric retention and drug delivery

Gastric retention drug delivery is experiencing significant demand for hydrogels that exhibit in situ controllable forming in the stomach, resistance against severe gastric degradation, and exceptional biocompatibility. However, current studies lack comprehensive investigations on these requirements. In this study, resistant starch is chosen as a kind of novel dietary fiber with remarkable gastric retention effects compared to conventional natural polymers. To address its limited solubility, resistant starch was modified by carboxymethyl groups. Moreover, a semi-dissolution acidification sol–gel transition method was employed to enable in situ gelation under gastric acid conditions and fabricate physically crosslinked polyelectrolyte composite hydrogels (CMRS/CTS) based on carboxymethylated resistant starch and chitosan. This method obviates the need for toxic chemical crosslinkers and initiators, ensuring favorable biocompatibility. The influence of carboxymethyl substitution degree and the anion-to-cation ratio of the composite hydrogels on the mechanical, rheological, and swelling properties was thoroughly investigated. Compared to conventional carboxymethyl starch-based hydrogels, CMRS/CTS maintained a relatively intact structure even after immersion in simulated gastric fluid for 30 days owing to the enzymatic stability of the hydrogel. Upon drug loading, CMRS/CTS exhibited sustained and controlled drug release, facilitating prolonged therapeutic effects. Simultaneously achieving in situ gastric drug release, biocompatibility, resistance to degradation, and sustained release, CMRS/CTS represents a promising avenue for the development of long-term gastric retention hydrogels.

Physical properties comparison of hydrogel from cassava starch using two different non toxic crosslinkers

For the purpose of improving mechanical qualities, starch-based film hydrogel can be crosslinked. The choice of crosslinking agent is critical in adjusting hydrogel performance to fit the needs of specific applications. The present investigation examined the impact of two non-toxic crosslinking agents, namely citric acid and oxidized sucrose, on the mechanical and swelling properties of hydrogels. When compared to oxidized sucrose crosslinked hydrogels (OSH), citric acid crosslinked hydrogels (CAH) often offer a larger swelling; however, OSH without plasticizer is not included in this comparison. The OSH has the highest swelling value of 292% at pH 7, whereas the CAH has the highest swelling value of 116% at pH 7. Contrary to OSH film, which can only achieve 2.0 MPa, CAH film has a tensile strength of up to 3.75 MPa. Meanwhile, OSH film can achieve the greatest elongation of 54%.

Enhanced mechanical and electrical properties of starch-based hydrogels incorporating polyacrylic acid and MXene for advanced wearable sensors in sign language recognition

A PAA/Starch/MXene organohydrogel was developed for strain sensors with remarkable sensitivity, offering potential for widespread applications in wearable electronics.