Search Results (168)

This study developed a sustainable and cost-effective method for producing alginate-encapsulated activated carbon hydrogel beads from almond shell waste biomass, aimed at the efficient removal of methylene blue (MB) dye from aqueous solutions. The activated carbons were developed by heating biomass to different temperatures (500, 600, and 700 °C) and then mixing them with a calcium alginate matrix biopolymer to make composite hydrogel beads labeled AC500@Alg, AC600@Alg, and AC700@Alg. Zeta potential measurement, SEM, EDS, and FTIR analyses were carried out to evaluate the structural, morphological, chemical, and surface properties of the beads. Adsorption experiments showed that raising the activation temperature greatly improved porosity, surface carbon content, and adsorption performance. Among the adsorbent beads, AC700@Alg hydrogel beads had the best ability to adsorb MB, with a maximum Langmuir monolayer capacity of 316.46 mg/g. The pH of the solution and the charge on the surface had a great effect on the adsorption process. The best removal was achieved at alkaline pH due to the electrostatic attractions. The pseudo-second-order model best explained the kinetic data, which meant that surface interactions controlled the adsorption process. Thermodynamic analysis verified that MB adsorption was spontaneous and endothermic. Also, AC700@Alg beads were reusable, keeping their removal efficiency at over 80% after four cycles of adsorption and desorption. These results show that alginate-encapsulated activated carbon made from agricultural waste could be a good, eco-friendly, and reusable adsorbent for cleaning up wastewater. Full article

To address the poor solubility, instability, and low oral bioavailability of quercetin (Q), Q-loaded nanoparticles (Q@DDZ) were fabricated using deamidated zein peptide (DDZ) via a pH-driven method. As a food-grade hydrophilic colloid, DDZ effectively improves the colloidal stability of the delivery system. Deamidation increased hydrophilic amino acids and surface negative charge. DDZ bound Q via static quenching with a higher binding constant (K_a = 2.25 × 10³ L/mol) and more binding sites (n = 1.7561) than zein, along with stronger hydrogen bonding and hydrophobic interactions. Q@DDZ exhibited higher encapsulation efficiency (45.36–87.32%) and loading capacity (1.82–12.27%) than Q@zein, with a smaller particle size and better dispersibility. At 50.0 μg/mL Q, Q@DDZ showed 41.06% (DPPH) and 46.62% (ABTS) higher scavenging rates than free Q. It displayed excellent stability under acidic, high ionic strength, and thermal conditions (80 °C, 180 min). In simulated digestion, Q@DDZ delayed Q release in the oral and gastric phases and prolonged intestinal release, which indicated potentially improved bioavailability. This study provides mechanistic insights into deamidation-modified plant protein delivery systems for hydrophobic bioactives, offering new perspectives for the development of functional biopolymer gel materials. Full article

This comprehensive review aims to cover the surface tribology and triboelectric properties of additively manufactured (AM) natural biopolymers, including cellulose, chitosan (CS) and silk fibroin (SF), in biomedical interface engineering. While these sustainable materials exhibit innate biocompatibility and tribopositivity, their baseline triboelectric performance demands targeted surface engineering. We synthesize key physical mechanisms governing charge generation, emphasizing how controlled surface roughness, hierarchical porosity and nanoscale architectures maximize contact electrification. Furthermore, distinct dielectric and polarity modulation strategies are evaluated across the biopolymer families: cellulose relies heavily on chemical functionalization to overcome weak native polarity; chitosan utilizes ionic coordination and fillers to elevate its relatively low charge density; and silk fibroin achieves exceptional power outputs via highly porous three-dimensional nanocomposite aerogels. AM technologies afford unprecedented spatial control over these biointerfaces but introduce severe processing constraints. Techniques such as those based on extrusion impose strict shear-thinning rheology and rapid crosslinking for cellulose and chitosan, while SF frequently suffers from crystallization-induced nozzle clogging, necessitating photocurable derivatives. Full article

Zeolitic imidazolate framework-8 (ZIF-8) is one of the most extensively studied metal–organic frameworks due to its high surface area, tunable porosity, chemical stability, and intrinsic antimicrobial activity. Recent research has focused on engineering ZIF-8 through metal doping and surface functionalization to enhance its physicochemical performance and expand its applications in food safety and environmental systems. Metal-doped ZIF-8 incorporating Cu²⁺, Fe²⁺/Fe³⁺, Ag⁺, or Mn²⁺ improves reactive oxygen species generation, enables controlled metal-ion release, and promotes synergistic bactericidal mechanisms against both Gram-positive and Gram-negative pathogens. In parallel, surface modification using biopolymers such as hyaluronic acid, chitosan, alginate, and polyethylene glycol enhances colloidal stability, reduces cytotoxicity, modulates surface charge, and improves adhesion to food-contact surfaces, thereby enhancing coating stability and sustained antimicrobial activity. These combined strategies support the development of multifunctional nanoplatforms with improved dispersibility, controlled release behavior, and compatibility with food packaging, sanitization, and water treatment applications. From a sustainability perspective, ZIF-8-based systems offer the potential to reduce reliance on conventional chemical disinfectants, minimize chemical residues, and enable the integration of biodegradable polymer matrices for safer and more environmentally responsible antimicrobial solutions. This review summarizes recent advances in synthesis strategies, structure–property relationships, antimicrobial and antibiofilm mechanisms, and environmental safety considerations. Key challenges, including scalability, regulatory acceptance, stability, and long-term ecotoxicological impact, are discussed, along with perspectives on stimuli-responsive systems, essential oil encapsulation, and smart antimicrobial coatings. Full article

Developing efficient and durable electrocatalysts for the alkaline hydrogen evolution reaction (HER) remains challenging due to intrinsically sluggish reaction kinetics and the limited long-term stability of many non-noble metal catalysts under continuous operation. Herein, a nickel-doped polypyrrole/chitosan composite electrode on stainless steel (PPy/Chi/Ni) was fabricated via electrodeposition as a low-cost and scalable method. Benefiting from the combined effects of Ni incorporation and the conductive polymer–biopolymer composite framework, the optimized PPy/Chi/Ni electrode exhibits enhanced HER activity in alkaline environment, delivering a low overpotential of η₁₀ = 78 mV at a current density of 10 mA·cm⁻² and a reduced Tafel slope of 93 mV·dec⁻¹, indicative of accelerated reaction kinetics. Structural and morphological characterizations by XRD, FTIR, and FESEM indicate the formation of the composite structure. FESEM images suggest that the deposited layer forms a relatively uniform coating on the stainless steel substrate. EIS further reveals improved interfacial charge-transfer characteristics upon Ni doping. Additionally, long-term stability tests confirm the structural integrity of the composite electrode and its electrochemical stability under HER conditions by demonstrating stable HER performance for 15 h with only a 22 mV potential change at a constant current density. By providing a conductive interface and numerous catalytic sites, the Ni-doped electrocatalyst coating activates the stainless steel substrate, leading to a 79% reduction in overpotential compared to bare stainless steel and thereby significantly improving its HER performance. Full article

Biobased hybrid semiconducting composites are attracting significant attention as sustainable alternatives to traditional inorganic photocatalysts for environmental remediation and energy-related applications. Recent research progress in biobased hybrid photocatalytic systems is critically reviewed to outline their design strategies, photocatalytic mechanisms, and environmental applications. These composites integrate bioderived polymers with metal oxide semiconductors, forming hybrid architectures that improve interfacial contact at the molecular level, enhance charge transfer efficiency, and impart higher structural flexibility. The polymer matrix not only provides mechanical adaptability and functional surface groups, but also serves as an environmentally friendly support that can modulate surface electronic states and influence the photoinduced electron–hole dynamics in the inorganic phase. By controlling the molecular interactions between the polymer chains and metal oxide surfaces, these hybrids can mitigate key limitations of conventional metal oxides, such as rapid electron–hole recombination and restricted visible-light absorption. This review first summarizes the fundamental electronic and structural properties of widely employed metal oxide semiconductors and highlights their intrinsic limitations in photocatalytic processes. It then examines the role of biopolymers from the perspective of molecular structure, charge transport pathways, and interfacial interaction mechanisms with the inorganic component. Various synthesis strategies—including sol–gel, hydrothermal, in situ nanoparticle generation, green synthesis, and surface functionalization—are discussed, with emphasis on their ability to tune the nanoscale morphology and interfacial chemistry of the hybrids. Applications of these biohybrid systems in dye degradation, pharmaceutical pollutant removal, heavy metal reduction, and antimicrobial photocatalysis are analyzed alongside mechanistic insights into charge separation efficiency and band alignment at the molecular interface. Furthermore, challenges related to long-term stability, reproducibility, scalability, and performance in real wastewater matrices are also addressed. Overall, this review provides a thorough discussion on the design principles, photocatalytic mechanism, and environmental applications of biobased hybrid semiconductors, while emphasizing future opportunities for the development of efficient and sustainable photocatalytic systems. Full article

One of the main sources of microplastic pollution in aquatic ecosystems is municipal wastewater, and preserving the ecological security of water depends on its effective removal. In this study, a potential multi-functionalized nanocomposite (NH₂-MIL-101(Fe)/CS/GO), which consists of an iron-based metal–organic framework (NH₂-MIL-101(Fe)) integrated with chitosan (CS) as a biopolymer matrix and graphene oxide (GO) as a conductive support, was exploited to enhance microplastic removal via different adsorptive hydrophilic/hydrophobic interactions. According to adsorption tests, the removal efficiencies of NH₂-MIL-101(Fe)/CS/GO for polyethylene terephthalate (PET) and polystyrene (PS) microplastics (25–30 μm) were 93.8% and 89.7%, respectively, at pH 6.2 and for 40 min of contact time. Adsorption isotherms were well fitted to both the Langmuir and the Freundlich models, and the maximum adsorption capacities of PET and PS were 321.4 and 255.1 mg·g⁻¹, respectively. The removal efficiency reached 92.5% after six cycles. The proposed MOF-based CS/GO nanocomposite provides an efficient and durable method of controlling microplastic contamination in urban wastewater. The developed multi-functionalized nanocomposite offers excellent electrostatic and hydrophobic synergy through a large surface area and π–π interactions for GO, positively charged CS, and a very high surface area with tunable porosity for the amino–MIL-101 (Fe) moiety. The proposed MOF-based nanocomposite provides an effective and persistent method of reducing microplastic contamination in constructed wetlands and water/wastewater treatment plants. Full article

Among the most structurally diverse biomacromolecules, polysaccharides have attracted increased attention as nanocarriers for precision medicine due to their inherent biocompatibility and versatility in functionalization. Molecular features, such as monomer composition, glycosidic linkages, charge density, and chemical modification, essentially determine the nanoscale assembly process of these biopolymers, as well as their biological compatibility. This review highlights the role of these properties in the assembly process of polysaccharide-based nanocarriers leading to a variety of self-assembled nanostructures, such as polyelectrolyte complexes, protein–polysaccharide complexes, amphiphilic micelles, vesicles, hybrid systems, and nanogels, which are extensively discussed throughout the review. This review also focuses on the structure–property–function relationships of nanocarriers as applied to the rapidly developing area of precision medicine, emphasizing the problems of sustainability and reproducibility. By combining the principles of molecular engineering, supramolecular assembly, and measurable properties, this work aims to present a unified view of the molecular engineering of polysaccharide-based nanocarriers for enhanced translation potential, as well as to outline a coherent framework for the rational development of next-generation polysaccharide-based nanocarriers with improved clinical relevance. Full article

Cellulose nanocrystals (CNCs) are highly desirable nanomaterials for reinforcing biopolymer films. Coconut husks are generated in massive quantities after harvesting and processing, leading to waste management issues. This study isolated and characterized CNCs from young (y-CNCs) and mature (m-CNCs) coconut husks via acid hydrolysis (32% H₂SO₄, 50 °C, 5 h), comparing them with commercial CNCs (c-CNCs) to evaluate their performance in gelatin-based films. TEM confirmed rod-shaped morphology for all CNCs. Notably, m-CNCs exhibited a smaller particle size (199 nm), a higher surface charge (−46.8 mV), and superior crystallinity (63.98%), demonstrating properties comparable to c-CNCs. FTIR and XRD confirmed characteristic cellulose functional groups and crystalline structure, while TGA demonstrated excellent thermal stability above 300 °C for all samples. Incorporation of CNCs into gelatin films significantly improved tensile strength (from 15.63 to 24.93 MPa) and reduced water vapor permeability (from 2.65 to 2.43 × 10⁻¹⁰ g m m⁻² s⁻¹ Pa⁻¹; p < 0.05). These findings demonstrate how coconut husk residues can be upcycled into high-value nanomaterials fostering economic growth with innovation in sustainable manufacturing. This research also promotes responsible waste utilization, highlighting the benefits of biodegradability and a reduced carbon footprint for sustainable food packaging applications. Full article

This study investigates the development and characterization of bioactive films incorporating silver nanoparticles (AgNPs) into biocompatible polymers, namely alginate and chitosan, fabricated using two methods, spin-coating and drop-casting, and aiming to enhance their antimicrobial properties. Dynamic light scattering (DLS) and electrophoretic mobility (EM) of the film precursor solutions revealed significant changes in the nanoparticles’ size and Zeta potential (ZP), reflecting the influence of polymer coatings. Alginate contributed to high electrostatic stability due to its negative charge, while chitosan facilitated specific interactions with negatively charged surfaces. Raman spectroscopy revealed that spin-coating conditions did not successfully result in film formation, highlighting the need for further optimization. Therefore, subsequent characterization studies were conducted only for the films formed by drop-casting. Topographical and nanomechanical assessments of these drop-cast films, using atomic force microscopy (AFM) and force spectroscopy, demonstrated that AgNPs reduced adhesion and elasticity in alginate films, while increasing rigidity and adhesion in chitosan-based films. Antimicrobial tests confirmed the efficacy of AgNPs in both precursor solutions and polymer films, with chitosan-based films that retained structural integrity, which makes them suitable for prolonged applications, while alginate films displayed rapid gelation upon hydration, potentially advantageous in short-term applications. The findings underscore the potential of these biopolymer-AgNP composites in creating antimicrobial materials for food packaging, wound dressings, and other biomedical applications. However, challenges related to film deposition methods, such as spin-coating, require further optimization to improve film formation and reproducibility. Full article

Membrane bioreactors (MBRs) exhibit highly variable removal efficiencies for pharmaceutical metabolites and organic micropollutants, even under similar operating conditions. Diclofenac and carbamazepine, for instance, show elimination rates that differ markedly across installations and studies. The membrane’s separation parameters—pore size, diameter, or structure—and the chemical nature of its material do not fully explain these differences. Instead, processes at the sludge–membrane interface, particularly sorption and biofilm-related interactions, appear to dominate. Recent studies indicate that MBR performance depends largely on events at the membrane surface: microbial adhesion mechanisms, biofilm development, and community organization. Better pollutant removal stems from prolonged contact with the biofilm and transformation within this layer, not from mechanical filtration alone. Here, we examine membrane surface modification strategies using biopolymers (cellulose, chitosan, and alginate) and their effects on membrane–biofilm interactions. Research suggests that effective biopolymer coatings for MBRs must stabilize the hydration layer, maintain near-neutral surface charge, show moderate cross-linking density for durability and flexibility, and create controlled nanotopography that favors porous, active biofilms over compact sludge layers. This understanding supports the development of durable, low-energy MBR membranes with improved stability and more predictable micropollutant removal in real-world applications. Full article

With the increasingly stringent environmental regulations, the development of high-performance and eco-friendly shale inhibitors for water-sensitive formations has become an urgent priority. Chitosan, a renewable biopolymer derived from chitin, has inherent potential as a shale inhibitor but is limited by low water solubility and suboptimal inhibition efficiency. To overcome these limitations, cationic quaternary ammonium groups were grafted onto chitosan through etherification with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHA), yielding chitosan quaternary ammonium chloride (QASC). Systematic evaluation through linear swelling, rolling recovery, and bentonite inhibition tests revealed QASC’s superior performance. Notably, 1% QASC reduced bentonite swelling to 28.1% after 16 h, outperforming 5% KCl (48.2%) and 1% polyetheramine (41.1%). Remarkably, QASC achieved 88.4% shale recovery at 150 °C significantly exceeding the values for polyetheramine (52%) and pure water (13.2%). Mechanistic analysis revealed that QASC inhibits clay hydration through dual mechanisms: (1) electrostatic and hydrogen-bond mediated adsorption on clay surfaces, effectively neutralizing surface charges and diminishing hydration films; (2) intercalation into clay interlayers to create a physical barrier against water invasion. This synergistic combination ensures stable inhibitory performance under elevated temperatures. Given its enhanced biodegradability, QASC emerges as a sustainable alternative to conventional inhibitors, effectively addressing the dual challenges of technical performance and environmental compatibility in shale gas drilling operations. Full article

Background: Cannabidiol (CBD), a non-psychoactive compound derived from Cannabis sativa, exhibits therapeutic potential for various conditions, including inflammation, pain, and skin disorders, making it a promising candidate for the topical treatment of psoriasis. However, its poor water solubility and instability limit its therapeutic efficacy. This study focuses on the development and characterization of CBD-loaded nanoemulsions using argan oil as the lipid phase, with and without a chitosan coating, which serves as a stabilizing and functional biopolymer. Methods: Nanoemulsions (NE) and chitosan-stabilized nanoemulsions (CS-NE), both without CBD (serving as controls), and CBD-loaded variants (CBD-NE and CBD-CS-NE) were prepared and characterized for their physicochemical properties, including pH, droplet size, polydispersity index (PDI), zeta potential (ζ-potential), and viscosity at various shear rates and temperatures. Stability was assessed over time, and drug release behavior was investigated through in vitro diffusion and ex vivo skin permeation studies, followed by kinetic modeling. Safety was evaluated through in vitro cytotoxicity assays using HaCaT keratinocyte cells, as well as in vivo toxicity studies using Caenorhabditis elegans (C. elegans). Results: The chitosan-coated formulations exhibited enhanced physical stability, nanoscale droplet size, a positive surface charge, and increased viscosity. Release studies demonstrated that CBD-CS-NE enabled controlled and sustained drug release, with a strong correlation to the Higuchi model, indicating diffusion-controlled permeation. Cytotoxicity assays indicated that CBD-CS-NE was non-toxic to cultured cells, while in vivo testing with C. elegans revealed sensitivity to chitosan-coated systems. Conclusions: These findings highlight the potential of CBD-loaded argan oil nanoemulsions, particularly those stabilized with chitosan, as potential topical delivery systems for managing psoriasis. Full article

This study presents the fabrication of composite photoelectrodes containing halogenated phthalocyanines (F₁₆CuPc and MnPcCl) embedded in polymeric matrices of PEDOT:PSS (poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrenesulfonate)) and PLA (polylactic acid biopolymer). These composites were deposited on PET, palm leaf, and wheat bagasse recyclable substrates, and were morphologically characterized. The reflectance for F₁₆CuPc/PEDOT:PSS is less than 8.5%, and that for MnPcCl/PLA changes depending on the substrate, ranging between 10% and 40%. Additionally, in the case of F₁₆CuPc/PEDOT:PSS, the Kubelka–Munk band gap is 3.7 eV, and in the case of F₁₆CuPc/PEDOT:PSS, the band gap varied between 2.85 and 3.47 eV. The composites were evaluated as electrodes in bio-based sustainable devices, fabricated with commercially available paper towels used as an organic membrane separator. The palm-device showed the best performance throughout its charge and discharge cycle. The device improves its performance at high speeds and reaches its highest peak at 100 mV s⁻¹ with 3.14 × 10⁴ μA. On the other hand, the greatest thermal stability for the composites is for those deposited onto bagasse substrate, reaching up to 220 °C and 357 °C for F₁₆CuPc/PEDOT:PSS and MnPcCl/PLA, respectively. Also, these composites exhibit charge–discharge behavior when studied in bio-based sustainable devices and can be used as electrodes. Full article

The development of eco-friendly antimicrobial materials is essential for addressing antibiotic resistance, while reducing environmental impact. In this study, bio-derived anionic and cationic cellulose nanofibers (a-CNF and c-CNF) were employed as templating matrices for the in situ hydrothermal synthesis of cellulose/ZnO nanohybrids. Physicochemical characterization confirmed efficient cellulose functionalization and high-quality nanofibrillation, as well as the formation of uniformly dispersed ZnO nanoparticles (≈10–20 nm) strongly integrated within the cellulose network. The ZnO content was 30 and 20 wt. % for a-CNF/ZnO and c-CNF/ZnO, respectively. Antibacterial evaluation against Escherichia coli and Staphylococcus aureus revealed enhanced activity for both hybrids, with c-CNF/ZnO displaying the lowest MIC/MBC values (50/100 μg/mL). Antiviral assays revealed complete feline calicivirus inactivation at 100 μg/mL for c-CNF/ZnO, while moderate activity was observed against bovine coronavirus, highlighting the role of surface charge. Cytotoxicity assays on mammalian cells demonstrated high biocompatibility at antimicrobial concentrations. Life cycle assessment showed that c-CNF/ZnO exhibits a lower overall environmental burden than a-CNF/ZnO, with electricity demand being the main contributor, indicating clear opportunities for further reductions through process optimization and scale-up. Overall, these results demonstrate that CNF/ZnO nanohybrids effectively combine renewable biopolymers with ZnO antimicrobial functionality, offering a sustainable and safe platform for biomedical and environmental applications. Full article