Cellulose Anionic Hydrogels Based on Cellulose Nanofibers As Natural Stimulants for Seed Germination and Seedling Growth

Nanocellulose-hydrogel hybrids: A review on synthesis and applications in agriculture, food packaging and water remediation

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NC-HHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

Effect of a sodium carboxymethyl cellulose composite hydrogel on tobacco growth and development under drought stress

In order to promote the growth and development of tobacco and reduce the adverse effects of drought on tobacco, acrylamide/sodium carboxymethyl cellulose/modified biochar hydrogel (AM/CMC/MB) was prepared by crosslinking polymerization reaction. The structural characteristics of the hydrogel were comprehensively analysed using Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Additionally, the water absorption capacity of the hydrogel was quantitatively evaluated. Furthermore, this study investigated the efficacy of AM/CMC/MB hydrogel in promoting the growth and development of potted tobacco seedlings under drought stress conditions. The results showed that the equilibrium solubility of AM/CMC/MB hydrogel was increased by 74.83 % and the diffusion process of water molecules followed the non-Fickian diffusion law compared with commercially available water retention agents. The openness of stomata of tobacco seedlings and the SPAD values were improved. The MDA (Malondialdehyde) content of tobacco seedlings was reduced by 47.50 %, CAT (Antioxidant enzymes catalase) and POD (Peroxidase) activities were increased by 198.15 % and 198.23 %, respectively. The total amount of metabolites detected after drought in tobacco seedlings supplemented with hydrogel AM/CMC/MB was increased by 50.33 % as compared to the control. This study provides a basis for the use of AM/CMC/MB as a water retention agent for tobacco growth and development.

The Effect of the Conformation Process on the Physicochemical Properties of Carboxymethylcellulose-Starch Hydrogels

This study discusses the preparation of biopolymeric hydrogels (a biomaterial) via different techniques, such as casting and extrusion, to compare the effects of the process and the use of citric acid as a crosslinker on the morphology, physicochemical properties, and degree of swelling of the hydrogel. Casting is widely used for its low cost and space-saving nature, but upscaling is problematic. Extrusion offers a way to produce materials in large quantities; these materials can undergo mechanical and thermal energy, which can significantly alter their properties. The samples obtained by extrusion had porous surfaces, which are critical for the water penetration and swelling of superabsorbent hydrogels. In contrast, the hydrogels produced by casting did not form pores, resulting in a lower degree of swelling. Extrusion increased the degree of swelling threefold due to the formation of pores, influencing water absorption and diffusion dynamics, especially in samples with higher starch content, where crosslinking occurred more effectively.

Self-assembly of differently charged trimesic based lithocholic amphiphiles and their assessment on antimicrobial and biostimulant properties

Biosurfactant based biostimulants plays a vital role in agriculture filed by enhancing the soil quality, promote plant growth, and eliminate plant pathogens, and increasing nutrient uptake. This manuscript describes the synthesis of trimesic based lithocholic ester functionalized amphiphiles (TMLCEA) with oppositely charged head groups using thiol-yne click chemistry, which is an effective and simple approach. The trimesic based lithocholic ester functionalized zwitterionic penicillamine (TMLCEPA), cationic cysteamine·HCl (TMLCECy), and anionic thiomalic acid (TMLCETM) exhibited hierarchically self-assembled microstructures from below to above the CMC. In below the CMC, TMLCEPA, TMLCECy, and TMLCETM showed a bundle of petals, flower-like morphology, and grass seed-like patterns respectively. The morphology of self-assembly was studied by FE-SEM, DLS, OPM, contact angle, and zeta potential measurements. Among these amphiphiles, TMLCECy exhibited potential antimicrobial activity at above the CMC. The biostimulant effect of different concentration of TMLCEA treated with maize and green gram seeds were evaluated under in vitro condition, wherein TMLCECy showed improved seed germination and seedling parameters at 750 µL/mL as compared to TMLCEPA, TMLCETM and untreated amphiphiles as control. Molecular docking and molecular dynamic simulations show that TMLCEPA and TMLCETM showed higher binding affinity for dengue methyltransferase protein. The result of the present study opens up new avenues for bile acid-based amphiphiles as bio-based and cost-effective biostimulants for sustainable agriculture.

Preparation of TEMPO-Oxidized Cellulose Hydrogels Modified with β-Cyclodextrin and κ-Carrageenan for Potential Adsorption Applications

Cellulose-based materials are promising adsorbents for pollutants and other classes of compounds. Here, we report the preparation of hydrogels via chemical cross-linking of microcrystalline cellulose oxidized by the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO). The cross-linking process was carried out in the presence of modifiers such as β-cyclodextrin in order to insert hydrophobic cavities or κ-carrageenan due to the presence of negative charges along the molecular chains. Fourier transform infrared spectroscopy (FTIR) characterization evidenced the modification of cellulose chains. Swelling tests showed that all hydrogels reached the swelling equilibrium in the first 10 min of contact, while N2 adsorption isotherms allowed to evaluate surface areas ranging from 211 to 697 m2/g. Adsorption studies using methylene blue showed the key role of negative charges present in polymer chains favoring interactions with this cationic dye, as hydrogels modified with κ-carrageenan were found to have a high adsorption performance. The kinetic analysis of the adsorption process also suggests contributions from chemical interactions, which may involve electron transfer or electron pairing, as the data from all hydrogels showed high-quality fitting with the pseudo-second-order model.

Lignin-based cryogels for advancing sustainable crop production via enhanced nutrient accessibility and growth efficiency

Sustainable lignin-based materials are becoming increasingly valuable in agriculture, where climate change and nutrient deficiencies threaten crop productivity. We developed lignin-derived cryogels using waste biomass to improve soil nutrients, seed germination, water retention, and photosynthetic pigment levels. These cryogels were synthesized with gum Arabic (GA), keratin (K), and N-vinylpyrrolidone at lignin concentrations of 0.02 wt% (LbC1), and 0.1 wt% (LbC2), along with a control (NLC), through low-temperature polymerization at -20 °C. The cryogels exhibited high thermal stability and water retention, exceeding 170 %, due to their network structure. Functional groups like carboxyl and hydroxyl enhanced nutrient assimilation, accelerating germination and plant growth, with keratin providing bioavailable amino acids through microbial degradation. After 5 days, the cryogel treatments significantly improved early germination rates (100 %, 100 %, and 99 % for wheat, maize, and rapeseed, respectively), while boosting chlorophyll (a, b, and total), sugar, and soluble protein levels. Treated plants showed increased leaf numbers, plant height, and root length, with a 98.4 % improvement in water uptake compared to controls, mitigating the effect of soil salinity. LbC1 and LbC2 also notably increased chlorophyll pigments, soluble sugars, and total protein across all crops compared to the NLC. Additionally, the cryogel exhibited a 33 % biodegradation rate after 130 days in soil, confirming their environmental compatibility. In conclusion, the developed lignin-based cryogels represent a sustainable, effective solution to enhance nutrient availability and resilience in agriculture, repurposing industrial lignin waste to address climate-driven challenges in crop production.

Facilitating Seed Iron Uptake through Amine-Epoxide Microgels: A Novel Approach to Enhance Cucumber (Cucumis sativus) Germination

Enhancing the initial stages of plant growth by using polymeric gels for seed priming presents a significant challenge. This study aimed to investigate a microgel derived from polyetheramine-poly(propylene oxide) (PPO) and a bisepoxide (referred to as micro-PPO) as a promising alternative to optimize the seed germination process. The micro-PPO integrated with an iron micronutrient showed a positive impact on seed germination compared with control (Fe solutions) in which the root length yield improved up to 39%. Therefore, the element map by synchrotron-based X-ray fluorescence shows that the Fe intensities in the seed primers with the micro-PPO-Fe gel are about 3-fold higher than those in the control group, leading to a gradual distribution of Fe species through most internal embryo tissues. The use of micro-PPO for seed priming underscores their potential for industrial applications due to the nontoxicity results in zebrafish assays and environmentally friendly synthesis of the water-dispersible monomers employed.

Agriculture 4.0: Polymer Hydrogels as Delivery Agents of Active Ingredients

The evolution from conventional to modern agricultural practices, characterized by Agriculture 4.0 principles such as the application of innovative materials, smart water, and nutrition management, addresses the present-day challenges of food supply. In this context, polymer hydrogels have become a promising material for enhancing agricultural productivity due to their ability to retain and then release water, which can help alleviate the need for frequent irrigation in dryland environments. Furthermore, the controlled release of fertilizers by the hydrogels decreases chemical overdosing risks and the environmental impact associated with the use of agrochemicals. The potential of polymer hydrogels in sustainable agriculture and farming and their impact on soil quality is revealed by their ability to deliver nutritional and protective active ingredients. Thus, the impact of hydrogels on plant growth, development, and yield was discussed. The question of which hydrogels are more suitable for agriculture-natural or synthetic-is debatable, as both have their merits and drawbacks. An analysis of polymer hydrogel life cycles in terms of their initial material has shown the advantage of bio-based hydrogels, such as cellulose, lignin, starch, alginate, chitosan, and their derivatives and hybrids, aligning with sustainable practices and reducing dependence on non-renewable resources.

Characterization of carboxylated cellulose nanofibrils and oligosaccharides from Kraft pulp fibers and their potential elicitor effect on the gene expression of Capsicum annuum

Biomass-derived oligo- and polysaccharides may act as elicitors, i.e., bioactive molecules that trigger plant immune responses. This is particularly important to increase the resistance of plants to abiotic and biotic stresses. In this study, cellulose nanofibrils (CNF) gels were obtained by TEMPO-mediated oxidation of unbleached and bleached kraft pulps. The molecular structures were characterized with ESI and MALDI MS. Analysis of the fine sequences was achieved by MS and MS/MS of the water-soluble oligosaccharides obtained by acid hydrolysis of the CNF gels. The analysis revealed the presence of two families: one corresponding to homoglucuronic acid sequences and the other composed by alternating glucose and glucuronic acid units. The CNF gels, alone or with the addition of the water-soluble oligosaccharides, were tested on Chili pepper (Capsicum annuum). Based on the characterization of the gene expression with Next Generation Sequencing (NGS) of the C. annuum's total messenger RNA, the differences in growth of the C. annuum seeds correlated well with the downregulation of the pathways regulating photosynthesis. A downregulation of the response to abiotic factors was detected, suggesting that these gels would improve the resistance of the C. annuum plants to abiotic stress due to, e.g., water deprivation and cold temperatures.

Increasing the efficiency of agricultural fertilizers using cellulose nanofibrils: A review

Developing new agricultural products, such as new fertilizers with high use efficiency and less negative impact on the environment, is required in sustainable agriculture. In this vein, controlled-release fertilizers (CRFs) have been designed to decrease nutrient waste and increase nutrients' availability to plants. Various CRFs have been developed based on petroleum-derived polymers with many advantages over conventional fertilizers. Although, their use is limited due to their adverse effects on the soil and environment. To overcome these issues, CRFs based on biopolymers represent a new generation of fertilizers developed by encapsulating nutrients with cellulose nanofibrils (CNFs). CNFs and the hydrogels based on CNFs have great potential to be applied as CRFs matrix as they are biodegradable, minimize environmental pollution, and exhibit a great controlled-release potential and water/nutrient retention capacity. In order to gain a better understanding of the potential benefits of these new fertilizers in agricultural systems, this review summarizes the recent advances in CNFs in CRFs, the coating methods, hydrogel preparation techniques, and their impact on plant growth and soil. By examining these factors in depth, a better understanding can be gained on how these novel fertilizers can help improve agricultural productivity and sustainability.

One-pot and one-step preparation of "living" cellulose nanofiber hydrogel with active double-bond via chemical vapor deposition

Due to the existence of water, it is still a challenge to conduct chemical modification on cellulose nanofiber (CNF) hydrogels with active double bonds. A simple one-pot and one-step method for constructing "living" CNF hydrogel with double bond was created at room temperature. The chemical vapor deposition (CVD) of methacryloyl chloride (MACl) was used to introduce physical-trapped, chemical-anchored and functional double bonds into TEMPO-oxidized cellulose nanofiber (TOCN) hydrogels. TOCN hydrogel could be fabricated within just 0.5 h, the minimum dosage of MACl could be reduced to 3.22 mg/g (MACl/TOCN hydrogel). Furthermore, the CVD methods showed high efficiency for mass production and recyclability. Moreover, the chemical "living" reactivity of the introduced double bonds were verified by the freezing and UV crosslinking, radical polymerization and thiol-ene click reaction. Compared with pure TOCN hydrogel, the obtained functionalized TOCN hydrogel exhibited remarkable improvements in mechanical properties, with enhancements of 12.34 times and 2.04 times, as well as an increase in hydrophobicity by 2.14 times and a fluorescence performance improvement of 2.93 times.

Emerging Frontiers in Nanotechnology for Precision Agriculture: Advancements, Hurdles and Prospects

This review article provides an extensive overview of the emerging frontiers of nanotechnology in precision agriculture, highlighting recent advancements, hurdles, and prospects. The benefits of nanotechnology in this field include the development of advanced nanomaterials for enhanced seed germination and micronutrient supply, along with the alleviation of biotic and abiotic stress. Further, nanotechnology-based fertilizers and pesticides can be delivered in lower dosages, which reduces environmental impacts and human health hazards. Another significant advantage lies in introducing cutting-edge nanodiagnostic systems and nanobiosensors that monitor soil quality parameters, plant diseases, and stress, all of which are critical for precision agriculture. Additionally, this technology has demonstrated potential in reducing agro-waste, synthesizing high-value products, and using methods and devices for tagging, monitoring, and tracking agroproducts. Alongside these developments, cloud computing and smartphone-based biosensors have emerged as crucial data collection and analysis tools. Finally, this review delves into the economic, legal, social, and risk implications of nanotechnology in agriculture, which must be thoroughly examined for the technology’s widespread adoption.

Recent Advances in Nano-Enabled Seed Treatment Strategies for Sustainable Agriculture: Challenges, Risk Assessment, and Future Perspectives

Agro seeds are vulnerable to environmental stressors, adversely affecting seed vigor, crop growth, and crop productivity. Different agrochemical-based seed treatments enhance seed germination, but they can also cause damage to the environment; therefore, sustainable technologies such as nano-based agrochemicals are urgently needed. Nanoagrochemicals can reduce the dose-dependent toxicity of seed treatment, thereby improving seed viability and ensuring the controlled release of nanoagrochemical active ingredients However, the applications of nanoagrochemicals to plants in the field raise concerns about nanomaterial safety, exposure levels, and toxicological implications to the environment and human health. In the present comprehensive review, the development, scope, challenges, and risk assessments of nanoagrochemicals on seed treatment are discussed. Moreover, the implementation obstacles for nanoagrochemicals use in seed treatments, their commercialization potential, and the need for policy regulations to assess possible risks are also discussed. Based on our knowledge, this is the first time that we have presented legendary literature to readers in order to help them gain a deeper understanding of upcoming nanotechnologies that may enable the development of future generation seed treatment agrochemical formulations, their scope, and potential risks associated with seed treatment.

Agricultural Applications of Superabsorbent Polymer Hydrogels

This review presents data from the past five years on the use of polymeric superabsorbent hydrogels in agriculture as water and nutrient storage and retention materials, as well as additives that improve soil properties. The use of synthetic and natural polymeric hydrogels for these purposes is considered. Although natural polymers, such as various polysaccharides, have undoubted advantages related to their biocompatibility, biodegradability, and low cost, they are inferior to synthetic polymers in terms of water absorption and water retention properties. In this regard, the most promising are semi-synthetic polymeric superabsorbents based on natural polymers modified with additives or grafted chains of synthetic polymers, which can combine the advantages of natural and synthetic polymeric hydrogels without their disadvantages. Such semi-synthetic polymers are of great interest for agricultural applications, especially in dry regions, also because they can be used to create systems for the slow release of nutrients into the soil, which are necessary to increase crop yields using environmentally friendly technologies.

Environmentally friendly hydrogel: A review of classification, preparation and application in agriculture

Superabsorbent hydrogel (SH) is three-dimensional (3D) cross-linked hydrophilic polymer that can absorb and retain large quantities of water or other aqueous solutions. SH is made of water-affinity monomers and is widely used in biomedicine, wastewater treatment, hygiene and slow-release fertilizers (SRFs). This article focused on the preparation methods of SH, superabsorbent hydrogel composite and the application of SH in agriculture. By selecting various synthetic technologies and cross-linking agents, a series of chemical cross-linking or physical networks can be designed and tailored to meet specific applications. In view of the excellent characteristics of water absorption, biodegradability, water retention and slow-release capacity, SH occupies a dominant position in the SRFs market. In this work, the agricultural application of SH in double coated SRFs and nutrients carriers is also discussed. Some mechanisms related to the nutrient release were analyzed by mathematical models. In addition, some agronomic benefits of using superabsorbent hydrogels in improving water absorption, water holding capacity and increasing crop yields were also discussed. Although SH has certain shortcomings, from the perspective of long-term development, it will further show great potential in sustainable agriculture.

Potential of chitosan/carbon nanoparticles and chitosan/lignocellulose nanofiber composite as growth media for peatland paddy seeds

Indonesia has committed to restoring degraded peatlands by revegetating them with paddy plants using paludiculture systems. Nanofertilizers derived from chitosan and oil palm biomass can be used to enhance paddy growth. This study analyzed the potential growth media of chitosan nanocomposite films for paddy seeds grown in tropical peatland. Chitosan nanocomposites were synthesized by reinforcing chitosan with activated carbon nanoparticles (ACNPs), nonactivated carbon nanoparticles (n-ACNPs), and lignocellulose nanofibers (LCNFs). All carbon nanoparticles were reversibly aggregated, whereas LCNFs did not have a tendency to aggregate but were entangled. The highest specific surface area and pore volume are on EFB ACNPs, followed by OPT LCNFs and EFB n-ACNPs. Both nanocomposites' tensile strength and elastic modulus value were reduced with an average of 45.77% and 34.00%, respectively, because of the lack of nano- and micro-aggregates formation, good dispersion, and incompatibility. In a germination test, chitosan nanocomposites provided the best growth patterns for the Dendang paddy variety, whereas, in a greenhouse test, the nanocomposites had the best growth patterns for the Indragiri paddy variety. Chitosan/empty fruit bunch ACNP nanocomposites grown in a germinator had the highest growth normality (100.00%), highest maximum growth potential (100.00%), and highest height average (11.27 cm). In the greenhouse test, chitosan/oil palm trunk n-ACNPs achieved the highest growth natality (16.44%) and growth rate (65.74%). All chitosan nanocomposites had a synergetic biofertilizing effect on fungi and mycorrhiza. Chitosan nanocomposites can be used as a growth regulator for peatland paddy varieties and can accelerate peatland restoration in tropical areas.

Agarose hydrogel composite supports microgreen cultivation with enhanced porosity and continuous water supply under terrestrial and microgravitational conditions

Hydrogels are attractive soilless media for plant cultivation with strong water and nutrient retention. However, pristine hydrogels contain mostly ultra-micro pores and lack air-filled porosity for root zone aeration. Herein we report a porous hydrogel composite comprising an agarose network and porous growing mix particle (GMP) fillers. The agarose backbone allowed the composite to sustain a 12-d growth cycle for red cabbage microgreens without the need for watering or crew interaction. Moreover, the GMP induced greater total pore volume and increased the prevalence of pores >30 μm by 8-fold. Further investigation suggested that the nutrients from GMP accounted for a 54 % increase in microgreen yield over pristine hydrogel, while the porous structure introduced by GMP improved the yield by another 44 %. Increased air-filled porosity accelerated the water transport and loss of hydrogel but maintained favorable water potential levels for plant extraction. Finally, the hydrogel composite supported microgreen growth satisfyingly under simulated microgravity despite some morphological changes. Results of this study reveal a novel growth substrate that is lightweight, convenient, and water-efficient, while effectively sustaining plant growth for multiple applications including indoor farming and space farming.

Selenium-agarose hybrid hydrogel as a recyclable natural substrate for selenium-enriched cultivation of mung bean sprouts

Selenium (Se) is an essential trace element for human beings and animals. Traditional plant Se enrichment technology suffers from selenium pollution. Herein, environmentally friendly Se-agarose (Se-Agar) hybrid hydrogels are prepared by simply mixing agar with different Se species including selenocarrageenan (SeCA), selenite and Se yeast under heating and stirring for 0.5 h without any other reagent. Such Se-Agar hybrid hydrogels with excellent biocompatibility were used as natural substrates for the cultivation of Se-enriched mung bean sprouts. Compared with Se yeast, SeCA and selenite show a better Se enrichment effect on mung bean sprouts. Furthermore, the growth indices including plant weight and plant height of mung bean sprouts were investigated with different concentrations and sources of Se. Notably, the Se-Agar hybrid hydrogels could be easily regenerated and reused for multiple cycles. The results indicated that Se-Agar hybrid hydrogels as recyclable natural substrates offer a simple, sustainable and affordable strategy for plant Se enrichment.

Preparation and applications of chitosan and cellulose composite materials

Chitosan is a natural fiber, chemically cellulose-like biopolymer, which is processed from chitin. Its use as a natural polymer is getting more attention because it is non-toxic, renewable, and biocompatible. However, its poor mechanical and thermal strength, particle size, and surface area restrict its industrial use. Consequently, to improve these properties, cellulose and/or inorganic nanoparticles have been used. This review discusses the recent progress of chitosan and cellulose composite materials, their preparation, and their applications in different industrial sectors. It also discusses the modification of chitosan and cellulose composite materials to allow their use on a large scale. Finally, the recent development of chitosan composite materials for drug delivery, food packaging, protective coatings, and wastewater treatment are discussed. The challenges and perspectives for future research are also considered. This review suggests that chitosan and cellulose nano-composite are promising, low-cost products for environmental remediation involving a simple production process.

Regenerated Cellulose Products for Agricultural and Their Potential: A Review

Cellulose is one of the most abundant natural polymers with excellent biocompatibility, non-toxicity, flexibility, and renewable source. Regenerated cellulose (RC) products result from the dissolution-regeneration process risen from solvent and anti-solvent reagents, respectively. The regeneration process changes the cellulose chain conformation from cellulose I to cellulose II, leads the structure to have more amorphous regions with improved crystallinity, and inclines towards extensive modification on the RC products such as hydrogel, aerogel, cryogel, xerogel, fibers, membrane, and thin film. Recently, RC products are accentuated to be used in the agriculture field to develop future sustainable agriculture as alternatives to conventional agriculture systems. However, different solvent types and production techniques have great influences on the end properties of RC products. Besides, the fabrication of RC products from solely RC lacks excellent mechanical characteristics. Thus, the flexibility of RC has allowed it to be homogenously blended with other materials to enhance the final products' properties. This review will summarize the properties and preparation of potential RC-based products that reflect its application to replace soil the plantation medium, govern the release of the fertilizer, provide protection on crops and act as biosensors.

A Smart Design Strategy for Super-Elastic Hydrogel with Long-Term Moisture, Extreme Temperature Resistance, and Non-Flammability

Elastic hydrogel is a promising material category for designing biological muscles, repairable building materials, flexible electronic devices, and vulcanized rubber substitutes, which is required to have a long life, good self-healing performance and extreme temperature tolerance. Herein, a super-elastic mineral hydrogel is developed with long-lasting moisture, based on dynamic physical crosslinking between hydrated calcium ion clusters and amide groups of polyacrylamide (PAM). The complex hydrogel exhibits a super stretchability of 13 600% at room temperature, and can maintain the super flexibility in a wide temperature range of -40-50 °C or for a long period of 28 days. Particularly, the soft material cannot be ignited under an open flame at 400-500 °C, because of coupling dual flame retardant mechanisms containing the endothermic effect of liquid water evaporation and the barrier effect of calcium mineral salt on oxygen. In conclusion, the novel complex hydrogel with excellent tensile property, stability in extreme temperature or long operating time, and flame retardancy may become a promising candidate in the fields of agriculture, food, construction, medicine, and machinery.

Mechanics Design in Cellulose-Enabled High-Performance Functional Materials

The abundance of cellulose found in natural resources such as wood, and the wide spectrum of structural diversity of cellulose nanomaterials in the form of micro-nano-sized particles and fibers, have sparked a tremendous interest to utilize cellulose's intriguing mechanical properties in designing high-performance functional materials, where cellulose's structure-mechanics relationships are pivotal. In this progress report, multiscale mechanics understanding of cellulose, including the key role of hydrogen bonding, the dependence of structural interfaces on the spatial hydrogen bond density, the effect of nanofiber size and orientation on the fracture toughness, are discussed along with recent development on enabling experimental design techniques such as structural alteration, manipulation of anisotropy, interface and topology engineering. Progress in these fronts renders cellulose a prospect of being effectuated in an array of emerging sustainable applications and being fabricated into high-performance structural materials that are both strong and tough.

Activated-carbon-filled agarose hydrogel as a natural medium for seed germination and seedling growth

An activated-carbon-filled agarose (Agar-AC) hydrogel containing various concentrations of activated carbon (AC) was successfully fabricated through a simple solvent cast technique. Compared to pure agarose hydrogels, Agar-AC hydrogels exhibited excellent mechanical properties, good thermal stability and a highly developed pore structure. The Agar-AC hydrogels also showed a certain degree of improvement in water retention performance, while their swelling ratio decreased with the addition of AC. The incorporation of AC did not influence the crystallinity of the agarose hydrogel, and no chemical modification occurred according to XRD and FTIR. In rapeseed seed germination experiments, the growth indexes of rapeseed, including the germination percentage, root length, stem length, fresh weight and dry weight, were enhanced by the incorporation of a suitable amount of AC. These results indicated that AC has great potential to enhance the properties of agarose hydrogels and improve seed germination and plant growth, which implies that Agar-AC hydrogels can be used as natural materials for agricultural applications.

Nanotechnology Potential in Seed Priming for Sustainable Agriculture

Our agriculture is threatened by climate change and the depletion of resources and biodiversity. A new agriculture revolution is needed in order to increase the production of crops and ensure the quality and safety of food, in a sustainable way. Nanotechnology can contribute to the sustainability of agriculture. Seed nano-priming is an efficient process that can change seed metabolism and signaling pathways, affecting not only germination and seedling establishment but also the entire plant lifecycle. Studies have shown various benefits of using seed nano-priming, such as improved plant growth and development, increased productivity, and a better nutritional quality of food. Nano-priming modulates biochemical pathways and the balance between reactive oxygen species and plant growth hormones, resulting in the promotion of stress and diseases resistance outcoming in the reduction of pesticides and fertilizers. The present review provides an overview of advances in the field, showing the challenges and possibilities concerning the use of nanotechnology in seed nano-priming, as a contribution to sustainable agricultural practices.

Plant-based nanocellulose: A review of routine and recent preparation methods with current progress in its applications as rheology modifier and 3D bioprinting

"Nanocellulose" have captivated the topical sphere of sturdily escalating market for sustainable materials. The review focuses on the comprehensive understanding of the distinct surface chemistry and functionalities pertaining to the renovation of macro-cellulose at nanodimensional scale to provide an intuition of their processing-structure-function prospective. The abundant availability, cost effectiveness and diverse properties associated with plant-based resources have great economical perspective for developing sustainable cellulose nanomaterials. Hence, emphasis has been given on nanocellulose types obtained from plant-based sources. An overarching goal is to provide the recent advancement in the preparation routes of nanocellulose. Considering the excellent shear thinning/thixotropic/gel-like behavior, the review provids an assemblage of publications specifically dealing with its application as rheology modifier with emphasis on its use as bioink for 3D bioprinting for various biomedical applications. Altogether, this review has been oriented in a way to collocate a collective data starting from the historical perspective of cellulose discovery to modern cellulosic chemistry and its renovation as nanocellulose with recent technological hype for broad spanning applications.

Celery cellulose hydrogel as carriers for controlled release of short-chain fatty acid by ultrasound

The feasibility of using celery cellulose hydrogels as carriers was explored for controlled release of short-chain fatty acids (SCFAs) triggered by ultrasound. The hydrogels were prepared with the phase inversion method and further characterized using FT-IR, SEM and XRD techniques. At the optimal cellulose concentration (8.33 and 6.25 mg/mL), the hydrogels (F₄ and F₅) exhibited the swelling ratio of 185%, and Young's modulus of the F₄ and F₅ was lower than that of others. The hydrogels were loaded with SCFAs owing to its hydrophilicity and swelling properties, and the maximum loading capacity of SCFAs achieved nearly 80%. Interestingly, the loaded SCFAs within hydrogel carrier could be readily released if an ultrasound trigger is exerted. Our results indicate that the ultrasound-triggered strategy for the SCFAs delivery system could provide a promising basis to achieve on-demand, reproducible, repeated, and tunable dosing of bioactive molecules.

Facile preparation of biomass lignin-based hydroxyethyl cellulose super-absorbent hydrogel for dye pollutant removal

The severe preparation process, poor swelling properties and mechanical properties of traditional cellulose and polyvinyl alcohol (PVA) composite hydrogels heavily limited their practical applications. To solve these issues, we use long-chain hydroxyethyl celluloses (HECs) as framework backbones, short-chain PVAs as branched chains, lignin molecules as extended crosslinkers and epichlorohydrin molecules as crosslinkers to prepare the lignin-based hydroxyethyl cellulose-PVA (LCP) super-absorbent hydrogels in the alkaline aqueous solution under mild reaction conditions, demonstrating high swelling ratio of up to 1220 g/g. The LCP hydrogels could take up large amounts of positively charged dyes rhodamine 6G, crystal violet and methylene blue with uptakes of 153, 184 and 196 mg/g, respectively. The LCP super-absorbent hydrogels also present excellent water retention, biodegradability and excellent swelling properties, which are very promising for applications in the fields of commercial diapers, soil water retention and seed cultivation in agriculture, and dye pollutant removal.

How rheological behaviors of concentrated starch affect graft copolymerization of acrylamide and resultant hydrogel

Corn starches with different amylose/amylopectin ratios were used to explore the effect of rheological behaviors of concentrated system on the graft copolymerization of acrylamide and resultant hydrogels, which sheds a light on their reactive extrusion process. The viscoelastic moduli of starch melts increased with increasing amylose content (AC), leading to a decreased extent of micro-mixing detected by a reduced rheokinetic rate. With increasing AC, the graft efficiency was decreased but with almost similar monomer conversion (about 87.5%) and nearly equivalent graft content. XRD and SAXS spectra revealed that the extent of retrogradation of the starches were increased and two-phase separation was enhanced for hydrogels with increasing AC. Interestingly, microscopic analysis showed the superabsorbent hydrogel from the starch with AC of 50% exhibited a gridding membrane porous structure, resulting in a higher water absorbent capacity of 550 g/g. This was attributed to the moderate crosslinking and the slightly greater graft content.

Synthesis and response of pineapple peel carboxymethyl cellulose-g-poly (acrylic acid-co-acrylamide)/graphene oxide hydrogels

Developing biomaterials derived from the renewable resources is an effective and sustainable approach to address environmental and resource issues. Herein, hydrogels were synthesized by grafting copolymerization of acrylic acid and acrylamide onto pineapple peel carboxymethyl cellulose with incorporation of graphene oxide (GO). The structure, swelling, and multiple responses to salt, pH and organic solvents were investigated. The incorporation of GO resulted in a higher cross-linking density of the network and thus decreased the swelling ability. Expansion of the hydrogels occurred at high pH, whereas shrinkage occurred at low pH or in salt solutions and organic solvents/water mixtures, exhibiting multiple responses to pH, salt and organic solvents. Moreover, the hydrogels showed a selective adsorption behavior to various dyes and the incorporation of GO enhanced the adsorption performance. The above results may allude several potential applications of the hydrogels, such as adsorption, smart actuators and drug release fields.

Ecotoxicological Properties of Tulipalin A-Based Superabsorbents versus Conventional Superabsorbent Hydrogels

The Phytotoxicological Aspects of a Novel Superabsorbent/Hydrogels: poly(acrylamide-co-sodium 4-hydroxy-2-methylenebutanoate), prepared from renewable monomer Tulipalin A, on the growth and development of monocotyledonous Avena sativa and dicotyledonous Raphanus sativus, was investigated and compared with the effect of borate-crosslinked poly(vinyl alcohol), poly(acrylamide), and poly(acrylamide-co-sodium acrylate) conventional hydrogels. Tulipalin A-based superabsorbent hydrogels revealed superior properties in terms of the combination of the tested properties. The results confirmed excellent suitability of Tulipalin A-based hydrogels for application as reservoirs of water during plant stress condition. Values of fresh matter (yield) and shoot height of the examined plants growing in soil amended with these hydrogels were ca 10% higher than those of plants growing in soil without hydrogels. Reference borate-crosslinked PVA hydrogels (containing increasing amount of borax cross-linker) revealed harmful effect on plants. The negative effect was observed on most of the investigated properties, increasing with content of the hydrogel in soil and concentration of the borax in it.

Gelatin-polysaccharide composite scaffolds for 3D cell culture and tissue engineering: Towards natural therapeutics

Gelatin is a promising material as scaffold with therapeutic and regenerative characteristics due to its chemical similarities to the extracellular matrix (ECM) in the native tissues, biocompatibility, biodegradability, low antigenicity, cost-effectiveness, abundance, and accessible functional groups that allow facile chemical modifications with other biomaterials or biomolecules. Despite the advantages of gelatin, poor mechanical properties, sensitivity to enzymatic degradation, high viscosity, and reduced solubility in concentrated aqueous media have limited its applications and encouraged the development of gelatin-based composite hydrogels. The drawbacks of gelatin may be surmounted by synergistically combining it with a wide range of polysaccharides. The addition of polysaccharides to gelatin is advantageous in mimicking the ECM, which largely contains proteoglycans or glycoproteins. Moreover, gelatin-polysaccharide biomaterials benefit from mechanical resilience, high stability, low thermal expansion, improved hydrophilicity, biocompatibility, antimicrobial and anti-inflammatory properties, and wound healing potential. Here, we discuss how combining gelatin and polysaccharides provides a promising approach for developing superior therapeutic biomaterials. We review gelatin-polysaccharides scaffolds and their applications in cell culture and tissue engineering, providing an outlook for the future of this family of biomaterials as advanced natural therapeutics.

Na-Montmorillonite-Dispersed Sustainable Polymer Nanocomposite Hydrogel Films for Anticancer Drug Delivery

Nanocomposite hydrogels have found a wide scope in regenerative medicine, tissue engineering, and smart drug delivery applications. The present study reports the formulations of biocompatible nanocomposite hydrogel films using carboxymethyl cellulose-hydroxyethyl cellulose-acrylonitrile-linseed oil polyol (CHAP) plain hydrogel and Na-montmorillonite (NaMMT) dispersed CHAP nanocomposite hydrogel films (NaCHAP) using solution blending technique. The structural, morphological, and mechanical properties of resultant nanocomposite hydrogel films were further investigated to analyze the effects of polyol and NaMMT on the characteristic properties. The synergistic effect of polyol and nanofillers on the mechanical strength and sustained drug-release behavior of the resultant hydrogel films was studied, which revealed that the increased cross-link density of hydrogels enhanced the elastic modulus (up to 99%) and improved the drug retention time (up to 72 h at both pHs 7.4 and 4.0). The release rate of cisplatin in nanocomposite hydrogel films was found to be higher in CHAP-1 (83 and 69%) and CHAP-3 (79 and 64%) than NaCHAP-3 (77 and 57%) and NaCHAP-4 (73 and 54%) at both pHs 4.0 and 7.4, respectively. These data confirmed that the release rate of cisplatin in nanocomposite hydrogel films was pH-responsive and increased with decrease of pH. All nanocomposite hydrogel films have exhibited excellent pH sensitivity under buffer solution of various pHs (1.0, 4.0, 7.4, and 9.0). The in vitro biocompatibility and cytotoxicity tests of these films were also conducted using 3-(4,5-dimethylthiazole-2-yl-2,5-diphenyl tetrazolium bromide) assay of human embryonic kidney (HEK-293) and human breast cancer (MCF-7) cell lines up to 48 h, which shows their biocompatible nature. However, cisplatin-loaded nanocomposite hydrogel films effectively inhibited the growth of human breast MCF-7 cancer cells. These studies suggested that the proposed nanocomposite hydrogel films have shown promising application in therapeutics, especially for anticancer-targeted drug delivery.

Molybdenum Sulfide Induce Growth Enhancement Effect of Rice ( Oryza sativa L.) through Regulating the Synthesis of Chlorophyll and the Expression of Aquaporin Gene

Molybdenum sulfide (MoS₂) has been applied widely in industrial and environmental application, leading to increasing release into environment. So far, no studies have been investigated with regard to the potential effect of MoS₂ on plants. Herein, we studied the impact of MoS₂ on the growth, chlorophyll content, lipid peroxidation, antioxidase system, and aquaporins of rice for the first time. Results showed that MoS₂ did not significantly affect the germination of rice seeds, malonaldehyde (MDA) content, and the antioxidant enzyme activity. While the length and biomass of rice root and shoot, chlorophyll content index (CCI), and expression of aquaporin genes were significantly increased. Based on these results, we concluded that MoS₂ promoted rice growth through (i) the promotion of nitrogen source assimilation, (ii) the enhancement of photosynthesis, enzymatic-related biochemical reactions, and metabolic processes, subsequently, (iii) the acceleration of cell division and expansion, furthermore (iv) no abiotic stress and favorable condition of antioxidant enzyme system. These results provided an important insight into the further application of MoS₂ on agriculture and environment.