Acid Grafting Research Articles

Chemoselective modification of chitosan with arginine and hydroxyproline: Development of antibacterial composite films for wound healing applications

This study explored the enhancement of chitosan for wound dressing applications through selective functionalization with arginine and hydroxyproline amino acids, combined with polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) in composite films. The research employed chemoselective amino acid grafting followed by solution casting to fabricate the composite materials. Fourier transform infrared (FTIR) analysis verified successful chitosan modification through the presence of a carbamate bond at 1719 cm−1 and an amide bond shift from 1660 to 1680 cm−1, with nuclear magnetic resonance (NMR) analysis providing additional confirmation. The composite films demonstrated exceptional properties, achieving maximum tensile strength of approximately 55 MPa and swelling ratio of about 400 %. Statistical analysis revealed significant variations in mechanical and swelling properties across formulations (p < 0.05), with analysis of variance (ANOVA) showing a between-group sum of squares of 122,980.519 for tensile strength and 352,306.333 for swelling. Duncan's multiple range test identified distinct groupings for tensile strength (5.67–119.67 MPa) and swelling ratios (320.33–565.33 %), demonstrating the impact of composition on material properties. Thermal stability analysis (25–600 °C) revealed a multi-step degradation process, confirming successful modification and composite formation. The amino acid-modified chitosan composites showed remarkable antibacterial enhancement, exhibiting 60 % greater activity against both Gram-positive and Gram-negative bacteria compared to unmodified chitosan. These findings demonstrate the potential of selectively functionalized chitosan composite films for advanced wound dressing applications, combining enhanced antibacterial efficacy with robust mechanical and thermal properties. Future research directions include formulation optimization and in vivo validation of clinical efficacy.

Effects of preheat treatment and syringic acid binding on the physicochemical, antioxidant, and antibacterial properties of black soybean protein isolate before and after in vitro digestion.

This study investigated the effects of preheat treatment (70-100 °C) and syringic acid (SA) grafting on the antioxidant, antibacterial, and physicochemical properties of black soybean protein isolate (BSPI) before and after in vitro digestion. The results revealed that both preheat treatment and SA grafting increased the digestibility and the absolute zeta potential value of BSPI. However, as the preheating temperature increased, the antioxidant ability of BSPI decreased, which was improved by SA grafting. During in vitro digestion, the absolute zeta potential and antioxidant activities of preheated BSPI and preheated BSPI-SA complex followed the order: intestine>gastric>before digestion. Compared with before digestion, preheated BSPI with its SA complex after in vitro digestion exhibited excellent antibacterial activities. Importantly, the preheated BSPI-SA complex enhanced the SA recovery rate during digestion and SA stability, with the highest recovery rate observed for the SA-grafted BSPI with preheat treatment at 100°C (BSPI100-SA). The principal component analysis sufficiently distinguished preheated BSPI and preheated BSPI-SA complexes. There were partitions between BSPI and BSPI-SA treated at different preheating temperatures. This study contributes to expanding the potential applications of BSPI with its SA complex in food products and offers guidance for designing SA delivery systems. PRACTICAL APPLICATION: Preheated BSPI-SA complexes could serve as functional ingredients in food or health products. Besides, preheated BSPI has application potential as a carrier for SA delivery.

Beyond the boundaries of organics biosorption: Reusable and cost-effective millet-straw-based carboxylate-functionalized mesoporous MCM-41

In this study, we prepared highly porous citric acid-functionalized mesoporous MCM-41 (C-MCM-41) molecular sieve adsorbent from millet straw agricultural residue, which was used for the effective remediation of wastewater contaminated with methylene blue (MB) and ciprofloxacin (CIP). The two-step synthesis process involved extracting highly pure silica from millet straw as a precursor for the ordered mesoporous silica MCM-41. The MCM-41 was synthesized via surfactant-mediated pore design before calcination, followed by citric acid grafting to improve surface functionality and enhance adsorption efficiency. Characterization techniques including XRD, SEM, HRTEM, FTIR, and zeta potential analysis confirmed the mesophase structure, honeycomb pore architecture, functional groups incorporation, and a more electronegative surface, respectively, due to the incorporated carboxyl moieties. Nitrogen adsorption-desorption studies showed a high surface area, which reduced slightly after functionalization. Adsorption of MB and CIP on the C-MCM-41 was superior to the unmodified MCM-41, and the Langmuir isotherm and pseudo-second-order models fitted the equilibrium and kinetic data, respectively. Reuse and cost analysis revealed that C-MCM-41 maintained over 90 % efficiency after four adsorption-desorption cycles and offers a sustainable and cost-effective alternative to conventional adsorbents, demonstrating higher efficiency in treating real wastewater. SynopsisSustainable and cost-effective silica was sourced from biomass and employed for the synthesis of reusable citric acid-functionalized ordered mesoporous silica which was used for the effective treatment of antibiotics contaminated wastewater

Magnetic graphene oxide grafted boronic acid-decorated metal-organic frameworks for selective enrichment of cis-diol-containing nucleosides

In this study, a novel magnetic graphene oxide grafted boronic acid-decorated metal-organic frameworks (Fe3O4@GO@BA-MOF) composite was developed for the selective enrichment of cis-diol-containing nucleosides. It is noteworthy that the amino-functionalized Fe3O4 was prepared by polyethyleneimine (PEI) as modifier, resulting in excellent durability and stability of magnetic nanoparticles under different environment, as well as introducing rich active functional groups for post-modification. GO with large surface area and abundant multi-active group was covalently bonded on amino-rich Fe3O4 as interlayer to facilitate the growth of BA-MOF with high boronic acid grafting density for selective capture of nucleosides. Due to the multi-interactions, especially the boronate affinity as well as the synergistic effect, the Fe3O4@GO@BA-MOF composite exhibited superior selectivity and adsorption capacity to nucleosides. Under the optimal conditions, an efficient magnetic solid-phase extraction-high-performance liquid chromatography technique was established using Fe3O4@GO@BA-MOF composite for the purpose of extracting and detecting nucleosides in urine, with recoveries ranging from 90.69 % to 110.36 %, relative standard deviations below 8.5 % and detection limits ranging from 0.004 to 0.010 μg mL−1. This study offers a new approach for preparation of high grafting density of boronic acid-decorated magnetic MOF, which is promising in selective enrichment of cis-diol-containing compounds in biological analysis.

Coagulopathy-independent injectable catechol-functionalized chitosan shape-memory material to treat non-compressible hemorrhage

Uncontrolled non-compressible hemorrhage, which is often accompanied by coagulopathy, is a major cause of mortality following traumatic injuries in civilian and military populations. In this study, coagulopathy-independent injectable catechol-modified chitosan (CS-HCA) hemostatic materials featuring rapid shape recovery were fabricated by combining controlled sodium tripolyphosphate-crosslinking with hydrocaffeic acid (HCA) grafting. CS-HCA exhibited robust mechanical strength and rapid blood-triggered shape recovery. Furthermore, CS-HCA demonstrated superior blood-clotting ability, enhanced blood cell adhesion and activation, and greater protein adsorption than commercial hemostatic gauze and Celox. CS-HCA showed enhanced procoagulant and hemostatic capacities in a lethal liver-perforation wound model in rabbits, particularly in heparinized rabbits. CS-HCA is suitable for mass manufacturing and shows promise as a clinically translatable hemostat.

Enhancing silica scaling resistance of high-pressure reverse osmosis membranes through surface grafting with various sulfonic acid monomers

Silica scaling is a major challenge in the application of high-pressure reverse osmosis (RO) membranes. In this work, we modified commercially available RO membranes by grafting different sulfonic acid monomers onto their surface using redox polymerization. We systematically studied the effects of various sulfonic acid monomers on membrane performance. Due to the different grafting abilities of sulfonic acid monomers on the membrane, the modified membranes exhibited different physicochemical properties. Simulated silica scaling experiments revealed that the initial permeate flux and sulfonic acid grafting rate of the membrane played crucial roles in its antifouling performance. Molecular dynamics (MD) simulation indicated that the adsorption of silica scale on the membrane was positively correlated with the grafting degree of sulfonic acid monomers. The membrane modified with 3-sulfopropyl potassium methacrylate (SPM) demonstrated a 14 % higher initial flux than the pristine membrane and the highest sulfonic acid grafting rate, resulting in the lowest flux decay rate. Additionally, the SPM modified membrane outperformed the pristine membrane against composite foulants with organic matters and silica. Our research demonstrated that the redox grafting polymerization of sulfonic acid monomers can simultaneously improve the flux and silica scaling resistance of RO membranes without compromising salt rejection. This provides a scalable strategy for preparing RO membranes with enhanced resistance to silica scaling.

Carbonized Polymer Dot-Tannic Acid Nanoglue: Tissue Reinforcement with Concurrent Fluorescent Tracking, Insulin Delivery, and Reactive Oxygen Species Regulation for Normal and Diabetic Wound Healing.

Nanotizing biosealant components offer a multitude of chemical functionalities for superior adhesion-cohesion, delivering unique properties for comprehensive wound healing that are otherwise impossible to achieve using commercial variants. For the first time, a two-step controlled hydrothermal pyrolysis is reported to nanotize dopamine, phloroglucinol, and glutaraldehyde into carbon dot (CD) to be subsequently converted into carbonized polymer dot (CPD) with gelatin as a co-substrate. Chemical crosslinking of CD with gelatin through Schiff base formation before the second pyrolysis step ensures a complex yet porous polymeric network. The retention of chemical functionalities indigenous to CD substrates and gelatin along with the preservation of CD photoluminescence in CPD for optical tracking is achieved. A unique nanoformulation is created with the CPD through tannic acid (TA) grafting evolving CPD-TA nanoglue demonstrating ≈1.32MPa strength in lap shear tests conducted on porcine skin, surpassing traditional bioadhesives. CPD-TA nanoglue uploaded insulin as chosen cargo disbursal at the wound site for healing normal and in vitro diabetic wound models using HEKa cells with extraordinary biocompatibility. Most importantly, CPD-TA can generate reactive oxygen species (ROS) and scavenge simultaneously under ambient conditions (23W white LED or dark) for on-demand sterilization or aiding wound recovery through ROS scavenging.

Therapeutic efficacy of Strobilanthes urticifolia-infused pectin/polyacrylic acid hydrogel for targeted hepatorenal fibrosis mitigation: A multifaceted biomaterial approach.

Pectin/polyacrylic acid (PPAA) hydrogel is a unique and versatile biomaterial with applications in drug delivery, wound healing, tissue engineering, and agriculture, owing to its tailored properties and multifunctional attributes. This study aims to harness the therapeutic potential of Strobilanthes urticifolia extract within a PPAA hydrogel matrix to attenuate liver and kidney fibrosis through targeted and sustained delivery of biologically active substances. PPAA hydrogel was prepared by free radical polymerization, followed by its porosity and swelling determination. The results depicted the porous nature of PPAA hydrogel and improved swelling properties at pH 7.4, confirming its drug delivery promise. The polyphenolic-enriched S. urticifolia extracts of leaf and flower were loaded onto PPAA hydrogel, and the loading efficiency was 87% (leaf) and 62.5% (flower). Moreover, slow-release studies showed controlled and prolonged release of polyphenols for 7 days. The polyphenolic-enriched hydrogel's microstructure was characterized using SEM, FTIR, and thermogravimetric analysis (TGA). SEM results revealed a highly porous structure of polyphenol enriched PPAA hydrogel, while FTIR analysis confirmed the presence of functional groups such as OH group of carboxylic acid, aliphatic CH2 stretching due to acrylic acid grafting with pectin, CO stretching due to acid linkage with pectin, CH of aromatic ring, and CH of carboxylate salt in PPAA hydrogel. TGA of PPAA hydrogel showed its stability up to 488°C. Additionally, the S. urticifolia extract loaded PPAA hydrogel displayed significant antibacterial properties and minimum inhibitory concentrations against both Gram-positive and Gram-negative bacteria. In vivo studies carried out on rats demonstrated that polyphenolic enriched PPAA hydrogel significantly attenuates liver and kidney fibrosis. Therefore, it is concluded from the present study that loading of polyphenolic enriched extract from leaves and flower of S. urticifolia enhanced the biomedical applications of PPAA hydrogel. RESEARCH HIGHLIGHTS: The PPAA hydrogel developed in this study exhibits a highly porous structure and improved swelling properties at physiological pH (7.4), making it an excellent candidate for drug delivery systems. S. urticifolia extracts, rich in polyphenols, were successfully incorporated into the PPAA hydrogel with high loading efficiencies of 87% for leaf and 62.5% for flower extracts. Loading of polyphenolic enriched extracts of S. urticifolia onto PPAA enhanced its biological activities such as antibacterial, hepatoprotective, and reno-protective activities as depicted by in vitro and in vivo studies.

Humic acid and grafting as sustainable agronomic practices for increased growth and secondary metabolism in cucumber subjected to salt stress

Salinity stress poses a significant treat to crop yields and product quality worldwide. Application of a humic acid bio stimulant and grafting onto tolerant rootstocks can both be considered sustainable agronomic practices that can effectively ameliorate the negative effects of salinity stress. This study aimed to assess the above mentioned ameliorative effects of both practices on cucumber plants subjected to saline environments. To attain this goal a factorial experiment was carried out in the form of a completely randomized design with three replications. The three factors considered were (a) three different salinity levels (0, 5, and 10 dS m−1 of NaCl), (b) foliar application of humic acid at three levels (0, 100, and 200 mg L−1), and (c) both grafted and ungrafted plants. Vegetative traits including plant height, fresh and dry weight and number of leaf exhibited a significant decrease under increasing salinity stress. However, the application of humic acid at both levels mitigated these effects compared to control plants. The reduction in relative water content (RWC) of the leaf caused by salinity, was compensated by the application of humic acid and grafting. Thus, the highest RWC (86.65%) was observed in grafting plants with 0 dS m−1 of NaCl and 20 mg L−1 of humic acid. Electrolyte leakage (EL) increased under salinity stress, but the application of humic acid and grafting improved this trait and the lowest amount of EL (26.95%) was in grafting plants with 0 dS m−1 of NaCl and 20 mg L−1 of humic acid. The highest amount of catalase (0.53 mmol H2O2 g−1 fw min−1) and peroxidase (12.290 mmol H2O2 g−1 fw min−1) enzymes were observed in the treatment of 10 dS m−1 of NaCl and 200 mg L−1 humic acid. The highest amount of total phenol (1.99 mg g−1 FW), total flavonoid (0.486 mg g−1 FW), total soluble carbohydrate (30.80 mg g−1 FW), soluble protein (34.56 mg g−1 FW), proline (3.86 µg g−1 FW) was in grafting plants with 0 dS m−1 of NaCl and 200 mg L−1 of humic acid. Phenolic acids and phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) enzymes increased with increasing salinity and humic acid levels. Contrary to humic acid, salt stress increased the sodium (Na+) and chlorine (Cl−) and decreased the amount of potassium (K+) and calcium (Ca2+) in the root and leaf of ungrafted cucumber. However, the application 200 mg L−1 humic acid appeared to mitigate these effects, thereby suggesting a potential role in moderating physiological processes and improving growth of cucumber plants subjected to salinity stress. According to the obtained results, spraying of humic acid (200 mg L−1) and the use of salt resistant rootstocks are recommended to increase tolerance to salt stress in cucumber. These results, for the first time, clearly demonstrated that fig leaf gourd a new highly salt-tolerant rootstock, enhances salt tolerance and improves yield and quality of grafted cucumber plants by reducing sodium transport to the shoot and increasing the amount of compatible osmolytes.

Surface Functionalization of Bamboo via Photo-Grafting Tannic Acid for Enhanced Silver Ion Loading Properties.

Photo-grafting is a gentle, simple, and precise approach to incorporating specific functional molecules for the surface functionalization of substrates. In this work, ultraviolet (UV)-induced tannic acid (TA) grafting onto the surface of bamboo was proposed as a viable strategy for functionalizing bamboo. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) clearly indicated that TA was successfully introduced to the bamboo's surface. The optimal conditions for the grafting reaction were determined to be 15 mM Methyl-2-benzoylbenzoate (BB), 30 mM TA, 20 min, and a pH = 8. Under these conditions, the amount of TA grafted onto the bamboo's surface was measured to be 19.98 μg/cm2. Results from Inductively Coupled Plasma (ICP) and Energy Dispersive Spectrometer (EDS) analyses showed that the silver ion loading capacity of tannic acid-grafted bamboo was significantly improved compared to that of raw bamboo and tannic acid-impregnated bamboo. Furthermore, the presence of TA grafted on the bamboo's surface exhibited a positive correlation with the loading of silver ions, indicating that grafted TA plays an important role in the surface functionalization of bamboo. We believe that photo-grafted TA may help generate multifunctional bamboo with diverse properties.

Economic and environmentally friendly anionic flocculant synthesized by starch-acrylic acid-itaconic acid grafting and efficient treatment of cationic dye wastewater

Starch-based flocculants are environmentally friendly and high-performance products, potentially applied in wastewater treatment with low operation cost and ecological risk. In this study, we successfully synthesized a ternary anionic copolymer of starch-acrylic acid-itaconic acid (SAI) through graft copolymerization. The synthesis conditions were optimized based on flocculation efficiency against cationic crystal violet (CV), and subsequent applicability was conducted under various environmental conditions. The results indicate that SAI exhibited outstanding decolorization efficiency under wide scopes of pH, temperature, and ionic strength. Most importantly, SAI achieved a remarkable decolorization rate of 91.2 % for 100 mg/L CV dye at a low concentration of 25 mg/L, accounting for one-fourth of the cost operated with commercial polyacrylamide. Compared to binary flocculants, SAI demonstrates superior flocculation performance too. The flocculation mechanism is primarily attributed to the combined effects of charge neutralization, bridging, and sweeping. SAI flocculants possess characteristics of high efficiency, environmental friendliness, and cost-effectiveness, thus presenting broad prospects for the treatment of dye wastewater.

Novel Formulations of Humic acid, Lignin, and Lignite Grafted Hydrogels for the Slow Release of Thiamethoxam

Novel Formulations of Humic acid, Lignin, and Lignite Grafted Hydrogels for the Slow Release of Thiamethoxam

Cover Picture: Novel Formulations of Humic acid, Lignin, and Lignite Grafted Hydrogels for the Slow Release of Thiamethoxam (ChemistrySelect 26/2024)

Cover Picture: Novel Formulations of Humic acid, Lignin, and Lignite Grafted Hydrogels for the Slow Release of Thiamethoxam (ChemistrySelect 26/2024)

Effects of chitosan-gentianic acid derivatives on the quality and shelf life of seabass (Lateolabrax maculatus) during refrigerated storage

Chitosan is a natural polymer material with antibacterial, biodegradable and biocompatibility. At present, the research is mainly to enhance the antibacterial and antioxidant activity of chitosan by grafting with phenolic acids to further expand its application in food. In this study, the effect of chitosan-g-gentisic acid graft copolymer (CS-g-GA) on the shelf life of refrigerated seabass (Lateolabrax maculatus) was investigated. The results of microbial analysis demonstrated that GA and CS-g-GA treatment could effectively inhibit the growth of microorganisms. In addition, physicochemical analysis showed that GA and CS-g-GA treatment could reduce the increase of pH value, thiobarbituric acid reactive substances (TBARS), total volatile base nitrogen (TVB-N) and K-value, delay water loss, maintain texture and color, and postpone the decrease of sensory score. Compared with the control sample, CS-g-GA could keep the quality of Lateolabrax japonicus and extend its shelf-life for another 9 days. In summary, CS-g-GA has good application and development prospects for the preservation of seabass.

Citrus flavonoids-loaded chitosan derivatives-route nanofilm as drug delivery systems for cutaneous wound healing

This study focuses on creating new forms of biomimetic nanofiber composites by combining copolymerizing and electrospinning approaches in the field of nanomedicine. The process involved utilizing the melt polymerization of proline (Pr) and hydroxyl proline (Hyp) to synthesize polymers based on Pr (PPE) and Hyp (PHPE). These polymers were then used in a grafting copolymerization process with chitosan (CS) to produce PHPC (1560 ± 81.08 KDa). A novel electrospun nanofiber scaffold was then produced using PHPC and/or CS, hyaluronic acid, polyvinyl alcohol, and naringenin (NR) as a loading drug. Finally, Mouse Dermal Fibroblast (MDF) cells were introduced to the wound dressing and assessed their therapeutic potential for wound healing in rats. The scaffolds were characterized by FTIR, NMR, DSC, and SEM analysis, which confirmed the amino acid grafting, loading drug, and porous and nanofibrous structures (>225 nm). The results showed that the PHPC-based scaffolds were more effective for swelling/absorption of wound secretions, had more elasticity/elongation, faster drug release, more MDF-cytocompatibility, and antibacterial activity against multidrug-resistant S. aureus compared to CS-based scaffolds. The in vivo studies showed that NR in combination with MDF can accelerate cell migration/proliferation, and remodeling phases of wound healing in both PHPC/CS-based scaffolds. Moreover, PHPC-based scaffolds promote collagen content, and better wound contraction, epithelialization, and neovascularization than CS-based, showing potential as wound-dressing.

Cellulose-based biomass composite films for plastic replacement: Synergistic UV shielding, antibacterial and antioxidant properties

With the gradual increase in environmental awareness and the growing demand for food safety, sustainable and environmentally friendly cellulose-based materials have become a promising alternative to petroleum-based plastics. However, in practice, packaging materials prepared from cellulose-based materials still have some unsatisfactory properties, such as monofunctionality, low transparency, and lack of UV shielding, antibacterial or antioxidant properties. Herein, a novel synthetic strategy is proposed in this paper, specifically, tannic acid (TA), a green natural extract with antibacterial and antioxidant properties, is used as a plasticizer and cross-linker, and oxidized cellulose nanocellulose (TOCN) modified with folic acid (FA) grafting is blended with TA, and cellulose-based biomass thin films with ultraviolet (UV) shielding, antibacterial, and antioxidant properties have been successfully prepared by using a simple vacuum-assisted filtration. The experimental results showed that the films could completely block ultraviolet light at wavelengths of 200–400 nm while providing 81.47 % transparency in the visible spectrum, while the introduction of TA conferred excellent antibacterial and antioxidant capabilities with antioxidant activity of up to 95 %, and also resulted in films with excellent mechanical properties. Therefore, this work provides ideas for the design and manufacture of competitive biomass green packaging materials, laying the foundation for future applications in food packaging.

Combined effect of polyelectrolyte assisted interfacial polymerization and tannic acid protective surface modification to boost organic solvent nanofiltration performance

Organic solvent nanofiltration (OSN) is an effective technology for separating solute with molecular weight of 200–1000 Da (Da) from organic solvents. However, as the core of this technology, most of OSN membranes exhibit a low solvent permeance. Herein, a highly permeable OSN membrane was prepared via a poly (sodium 4-styrenesulfonate) (PSSNa)-assisted interfacial polymerization reaction using ultra-low content of aqueous monomer solution, followed by a protective modification using tannic acid (TA) grafting onto the nascent polyamide surface, and a post chemical crosslinking treatment as well as an activation treatment. PSSNa manipulates the diffusion and distribution of the m-Phenylenediamine monomers, leading to a looser and thinner polyamide layer. TA molecules successfully reacted with the remaining acyl chloride groups on the nascent polyamide layer surface and formed ester, thus preventing the surface from subsequent crosslinking reaction and also making the selective layer looser, which is beneficial for solvent permeation. Moreover, the TA modification makes the surface more hydrophilic, thus further helps to improve the solvent permeance of OSN membrane. The optimal membrane possesses an excellent ethanol permeance of 71.5 L m−2 h−1 MPa−1, an increment of 41.6 % as compared with the baseline OSN membrane, while keeping a rejection of 98.2 % for rhodamine B (RDB). Meanwhile, the surface of optimal membrane is ultra-smooth, with an average roughness of 4.4 nm, which is much beneficial for antifouling. Moreover, the OSN membrane possesses a brilliant durability performance, with only a 1.5 % decrease of the RDB rejection after being immersed in N, N-Dimethylformamide (DMF) at room temperature for 115 d, and only a further 0.3 % decrease of the RDB rejection after being further immersed in DMF at 80 °C for another 11 d, indicating its superior solvent resistance, which makes it a promising candidate for treating organic solutions from pharmaceutical and textile industries.

Unlocking Heavy Metal Remediation Potential: A Review of Cellulose–Silica Composites

This comprehensive review explores recent advancements in heavy metal remediation techniques, focusing on the utilization of cellulose–silica composites and tailored surface modification techniques. We examine the synthesis strategies and properties of cellulose–silica adsorbents, highlighting their enhanced adsorption capacities and structural robustness for removing heavy metal pollutants from aqueous environments. The review investigates various surface modification approaches, including thiol functionalization, amino acid grafting, and silane coupling agents, for optimizing the surface chemistry and morphology of cellulose–silica composites. Mechanistic insights into the adsorption processes and kinetics of modified adsorbents are discussed, along with considerations for optimizing adsorption performance under different environmental conditions. This review provides valuable perspectives on the development of effective adsorbent materials for sustainable heavy metal remediation applications.

Novel hydrocolloids synthesized by polyphenols grafted onto chitosan: A promising coating to inhibit PhIP formation during pan-frying of golden pompano fillets

Hydrocolloids synthesized by gallic acid (GA) and ferulic acid (FA) grafting onto chitosan (CS) were characterized, and their effects on PhIP formation in pan-fried golden pompano were investigated. Spectrograms including nuclear magnetic resonance, Fourier transform infrared spectroscopy and ultraviolet-visible confirmed that GA and FA were successfully grafted onto CS via covalent bonds, with grafting degree of 97.06 ± 2.56 mg GA/g and 93.56 ± 2.76 mg FA/g, respectively. The CS-g-GA and CS-g-FA exerted better solubility and antioxidant activities than CS. For the 8-min pan-fried golden pompano fillets, CS-g-GA and CS-g-FA (0.5 %, m/v) significantly reduced the PhIP formation by 61.71 % and 81.64 %, respectively. Chemical models revealed that CS-g-GA and CS-g-FA inhibited PhIP formation mainly by decreasing the phenylacetaldehyde contents from Maillard reaction and competing with creatinine to react with phenylacetaldehyde. Therefore, it was suggested that CS-g-phenolic acids emerge as novel coating for aquatic products during processing and inhibit heterocyclic amines generation.

Exploring the emulsification potential of chitosan modified with phenolic acids: Emulsifying properties, functional activities, and application in curcumin encapsulation

This study successfully grafted caffeic acid and 3,4-dihydroxybenzoic acid into chitosan through a coupling reaction, yielding grafting ratio of 8.93 % for caffeic acid grafted chitosan (CA-GC) and 9.15 % for 3,4-dihydroxybenzoic acid grafted chitosan (DHB-GC) at an optimal concentration of 4 mmol phenolic acids. The characterization of modified chitosans through ultraviolet visible spectrometer (UV–vis), Fourier transform infrared spectrometer (FTIR), proton nuclear magnetic resonance (1H NMR), and x-ray photoelectron spectrometer (XPS) confirmed the successful grafting of phenolic acids. In the subsequent step of emulsion preparation, confocal laser scanning microscope images confirmed the formation of O/W (oil-in-water) emulsions. The phenolic acid-grafted chitosans exhibited better emulsification properties compared to native chitosan, such as reduced droplet size, more uniform emulsion droplet distribution, increased ζ-potential, and enhanced emulsifying activity and stability. Moreover, the modified chitosans demonstrated increased antioxidant activities (evidenced by DPPH and β-carotene assays) and displayed greater antimicrobial effects against E. coli and S. aureus. Its efficacy in curcumin encapsulation was also notable, with improved encapsulation efficiency, sustained release rates, and enhanced storage and photostability. These findings hint at the potential of modified chitosans as an effective emulsifier.