Preparation, characterization and antioxidant properties of curcumin encapsulated chitosan/lignosulfonate micelles

Novel self-assembled micelles of dual-modified dextrin with pH responsiveness via grafted octenyl succinic anhydride and cysteamine for curcumin delivery

In this study, a novel dextrin-based micelle (OSAD-SH), dual-modified with octenyl succinic anhydride (OSA) and cysteamine, was developed to address the acid instability issues of micelle modified only by OSA and designed for curcumin delivery. Three amphiphilic OSAD-SH polymers with different free sulfhydryl content were first synthesized. The study demonstrated that OSAD-SH micelles exhibited strong self-assembly properties, appearing as spheres with diameters ranging from 92.41 to 194.20 nm. Blank micelles showed good dilution resistance, as well as stability against acid, thermal, and ionic strength. The curcumin encapsulated by the micelles was in an amorphous state. In vitro release experiment demonstrated that curcumin released from OSAD-SH micelles exhibited pH responsiveness. The Ritger-Peppas model effectively predicted the release behavior of curcumin, which followed a super case-II transport. The OSAD-SH micelle will be a promising nanocarrier for improving the physicochemical properties of curcumin in food fields.

Lignin nanoparticle as a vehicle to load, release, and improve the stability and antioxidant activity of curcumin: Comparison between dropping and pouring regimes

Curcumin (Cur) was loaded in lignin nanoparticles (LNP) via an antisolvent method by pouring (P-) and dropping (D-) regimes, respectively, and Cur-loaded LNP (Cur/LNP) were comparatively characterized. The results indicated that P-Cur/LNP (62-92 nm) was much smaller than D-Cur/LNP (134-139 nm). For both regimes, their maximum loading efficiencies were comparable (91 ± 3%), while dropping regime (236.2 mg/g) demonstrated a higher loading capacity than pouring regime (174.6 mg/g). In both regimes, Cur was loaded in an amorphous form via the hydrophobic, hydrogen-bonding, and π-π interactions with lignin matrix and it demonstrated a controlled release in in vitro digestion test. In comparison, Cur in D-Cur/LNP showed higher stabilities against photodegradation, thermal treatment, and 30-d storage than that in P-Cur/LNP, while P-Cur/LNP concluded a higher antioxidant activity than D-Cur/LNP. The present findings attested that LNP was a valuable tool to stabilize and controlled release of lipophilic phytochemicals as well as improve their bioactivities.

Lignin self-assembly phenomena and valorization strategies for pulping, biorefining, and materials development: Part 1. The physical chemistry of lignin self-assembly

Physical chemistry aspects are emphasized in this comprehensive review of self-assembly phenomena involving lignin in various forms. Attention to this topic is justified by the very high availability, low cost, and renewable nature of lignin, together with opportunities to manufacture diverse products, for instance, polymers/resins, bioplastics, carbon fibers, bio-asphalt, sunscreen components, hydrophobic layers, and microcapsules. The colloidal lignin material, nanoparticles, and microstructures that can be formed as a result of changes in solvent properties, pH, or other adjustments to a suspending medium have been shown to depend on many factors. Such factors are examined in this work based on the concepts of self-assembly, which can be defined as an organizing principle dependent on specific attributes of the starting entities themselves. As a means to promote such concepts and to facilitate further development of nano-scale lignin products, this article draws upon evidence from a wide range of studies. These include investigations of many different plant sources of lignin, processes of delignification, solvent systems, anti-solvent systems or other means of achieving phase separation, and diverse means of achieving colloidal stability (if desired) of resulting self-assembled lignin structures. Knowledge of the self-organization behavior of lignin can provide significant structural information to optimize the use of lignin in value-added applications. Examples include chemical conditions and preparation procedures in which lignin-related compounds of particles organize themselves as spheres, hollow spheres, surface-bound layers, and a variety of other structures. Published articles show that such processes can be influenced by the selection of lignin type, pulping or extraction processes, functional groups such as phenolic, carboxyl, and sulfonate, chemical derivatization reactions, solvent applications, aqueous conditions, and physical processes, such as agitation. Precipitation from non-aqueous solutions represents a key focus of lignin self-assembly research. The review also considers stabilization mechanisms of self-assembled lignin-related structures.

Fabrication of polysaccharide-coated oleanolic acid-curcumin-coassembled nanoparticles (OA/Cur NPs): Enhancement of colloidal stability and water solubility

Natural terpenoid carriers, such as oleanolic acid (OA), can enhance the water solubility and stability of hydrophobic compounds such as curcumin (Cur). However, improving the colloidal stability of nanoparticle emulsions and resolving the redispersion problem of freeze-dried nanoparticle powders remain significant challenges. In this study, we fabricated coassembled oleanolic acid-curcumin nanoparticles (OA/Cur NPs) and applied a polysaccharide surface coating method to improve their colloidal stability and water solubility. The results showed that the optimal ratio of Cur/OA for preparing OA/Cur NPs was 4:10, resulting in a high encapsulation efficiency (EE) of Cur (75.2%). Additionally, TEM, contact angle tests, Turbiscan TOWER optical stability analysis of the polysaccharide-coated OA/Cur NP emulsions and redispersion tests of their lyophilized powders verified the advantages of carboxymethyl chitosan/β-cyclodextrin (CMC/β-CD) coating over other polysaccharides. This study indicated that polysaccharide coating is an effective method for enhancing the colloidal stability, water solubility, and redispersibility of OA/Cur NPs.

Fabrication and characterization of polydopamine-mediated zein-based nanoparticle for delivery of bioactive molecules

In this study, a combination of whey protein (hydrophilic coating) and polydopamine (crosslinking agent) was used to improve the stability and functionality of quercetin-loaded zein nanoparticles. There are two key benefits of the core-shell nanoparticles formed. First, the ability of the polydopamine to bind to both zein and whey protein facilitates the formation of a stable core-shell structure, thereby protecting quercetin from any pro-oxidants in the aqueous surroundings. Second, neutral and hydrophilic whey proteins were used for the surface coating of the nanoparticles to further enhance the sustained and slow release of quercetin, facilitating its sustained release into the body at a slow and steady rate. The results of this study will promote the innovative development of precise nutritional delivery systems for zein and provide a theoretical basis for the design and development of dietary supplements based on hydrophobic food nutrient molecules.

Ultrasmall magnolol/ebselen nanomicelles for preventing renal ischemia/reperfusion injury

Renal ischemia/reperfusion injury (RIRI) is an inevitable complication following kidney transplantation surgery, accompanied by the generation of a large amount of free radicals. A cascade of events including oxidative stress, extreme inflammation, cellular apoptosis, and thrombosis disrupts the microenvironment of renal cells and the hematological system, ultimately leading to the development of acute kidney injury (AKI). The current research primarily focuses on reducing inflammation and mitigating damage to renal cells through antioxidative approaches. However, studies on simultaneously modulating the renal hematologic system remain unreported. Herein, potent and novel drug-loaded nanomicelles can be efficiently self-assembled with magnolol (MG) and ebselen (EBS) by π-π conjugation, hydrophobic action and the surfactant properties of Tween-80. The ultrasmall MG/EBS nanomicelles (average particle size: 10-25 nm) not only fully preserve the activity of both drugs, but also greatly enhance drug utilization (encapsulation rates: MG: 90.1%; EBS: 49.3%) and reduce drug toxicity. Furthermore, EBS, as a glutathione peroxidase mimic and NO catalyst, combines with the multifunctional MG to scavenge free radicals and hydroperoxides, significantly inhibiting inflammation and thrombosis while effectively preventing apoptosis of vascular endothelial cells and renal tubular epithelial cells. This study provides a new strategy and theoretical foundation for the simultaneous regulation of kidney cells and blood microenvironment stability.

Fatty acid-modified chitosan and nanoencapsulation of essential oils: A snapshot of applications

Chitosan (CS) and its modification with fatty acid (FA) in addition to the nanoencapsulation with essential oils (EOs) have emerged as promising approaches with diverse applications, particularly in food and fruit preservation. This review aims to curate data on the prospects of CS modified with FA as nanostructures, serving as carriers for EOs and its application in the preservation of fruits. A narrative review with no restricted period was used for the general overview of CS and strategies for its modification with FA. Report on CS modified with FA and nanoencapsulation with EO and their applications were appraised. The prospects of CS modified with FA and EO nanoencapsulation in food and fruit preservation were outlined. Most chitosan-fatty acid (CS-FA) studies have found relevance in water, medical and pharmaceutical industries, with few studies on food preservation. CS-FA formulation with EOs shows substantial potential in preserving fruits and will significantly impact the food industry in the future by extending the shelf life of fruits and reducing food waste.

Curcumin-loaded food-grade nano-silica hybrid material exhibiting improved photodynamic effect and its application for the preservation of small yellow croaker (Larimichthys polyactis)

Two types of curcumin-loaded food-grade nano-silica (F-SiO2) hybrid materials were successfully synthesized using the rotary evaporation method (F-SiO2@Cur) and the adsorption method (Cur@F-SiO2). The microstructure and spectral analyses confirmed that the curcumin in F-SiO2@Cur was loaded within the nanopores in a non-aggregate form rather than being adsorbed onto the surface (Cur@F-SiO2). Additionally, F-SiO2@Cur exhibited remarkable water solubility (1510 ± 50.33 µg/mL) and photostability (a photodegradation ratio of only 59.22 %). Importantly, F-SiO2@Cur obtained a higher capacity for the generation of singlet oxygen (1O2) compared to control groups. Consequently, F-SiO2@Cur-mediated photodynamic inactivation (PDI) group attained the highest score in sensory evaluation and the best color protection effect in PDI experiment of small yellow croaker (Larimichthys polyactis) at 4 °C. Moreover, F-SiO2@Cur could effectively controlled total volatile basic nitrogen (TVB-N) content, pH, and total viable count (TVC), thereby prolonging the shelf life. Therefore, F-SiO2@Cur-mediated PDI is an effective fresh-keeping technology for aquatic products.

Curcumin-loaded scaffolds in bone regeneration

In recent years, there has been a notable surge in the development of engineered bone scaffolds intended for the repair of bone defects. While autografts and allografts have traditionally served as the primary methods in bone tissue engineering, their inherent limitations have spurred the exploration of novel avenues in biomedical implant development. The emergence of bone scaffolds not only facilitates bone reconstruction but also offers a platform for the targeted delivery of therapeutic agents. There exists a pervasive interest in leveraging various drugs, proteins, growth factors, and biomolecules with osteogenic properties to augment bone formation, as the enduring side effects associated with current clinical modalities necessitate the pursuit of safer alternatives. Curcumin, the principal bioactive compound found in turmeric, has demonstrated notable efficacy in regulating the proliferation and differentiation of bone cells while promoting bone formation. Nevertheless, its utility is hindered by restricted water solubility and poor bioavailability. Strategies aimed at enhancing the solubility, stability, and bioavailability of curcumin, including formulation techniques such as liposomes and nanoparticles or its complexation with metals, have been explored. This investigation is dedicated to exploring the impact of curcumin on the proliferation, differentiation, and migration of osteocytes, osteoblasts, and osteoclasts.

Micellar delivery systems of bioactive compounds for precision nutrition

Rapid changes in lifestyle and the increasingly hectic pace of life have led to a rise in chronic diseases, such as obesity, inflammatory bowel disease, liver disease, and cancer, posing significant threats to public health. In response to these challenges, precision nutrition (PN) has emerged as a secure and effective intervention aiming at human health and well-being. Bioactive compounds (bioactives), including carotenoids, polyphenols, vitamins, and polyunsaturated fatty acids, exhibit a range of beneficial properties, e.g., antioxidant and anti-inflammatory effects. These properties make them promising candidates for preventing or treating chronic diseases and promoting human health. However, bioactives might have different challenges when incorporated into food matrices and oral administration, including low water solubility, poor physiochemical stability, and low absorption efficiency. This limits them to achieve the health benefits in the body. Numerous strategies have been developed and utilized to encapsulate and deliver bioactives. Micellar delivery systems, due to their unique core-shell structure, play a pivotal role in improving the stability, solubility, and bioavailability of these bioactives. Moreover, through innovative design strategies, micellar delivery systems can be tailored to offer targeted and controlled release, thus maximizing the potential of bioactives in PN applications. This chapter reveals details about the preparation methods and properties of micelles and highlights the strategies to modulate the properties of polymeric micelles. Afterwards, the application of polymeric micelles in the delivery of bioactives and the corresponding PN, including controlled release, organ-targeting ability, and nutritional intervention for chronic disease are summarized.

Fabrication of lignosulfonate-derived porous carbon via pH-tunable self-assembly strategy for efficient atrazine removal

Herein, a straightforward protocol was developed for the one-pot synthesis of N-doped lignosulfonate-derived carbons (NLDCs) with a tunable porous structure using natural amino acids-templated self-assembly strategy. Specifically, histidine was employed as a template reagent, leading to the preparation of 10-NLDC-21 with remarkable characteristics, including the large specific surface area (SBET = 1844.5 m2/g), pore volume (Vmes = 1.22 cm3/g) and efficient adsorption for atrazine (ATZ) removal. The adsorption behavior of ATZ by NLDCs followed the Langmuir and pseudo-second-order models, suggesting a monolayer chemisorption nature of ATZ adsorption with the maximum adsorption capacity reached up to 265.77 mg/g. Furthermore, NLDCs exhibited excellent environmental adaptability and recycling performance. The robust affinity could be attributed to multi-interactions including pore filling, electrostatic attraction, hydrogen bonding and π-π stacking between the adsorbents and ATZ molecules. This approach offers a practical method for exploring innovative bio-carbon materials for sewage treatment.

Enhanced bioavailability of curcumin amorphous nanocomposite prepared by a green process using modified starch

Curcumin (Cur), a bioactive compound extracted from plants, has attracted widespread attention due to its multiple pharmacological activities. However, the low bioavailability due to the inherent limitations in water solubility, chemical stability, and permeability poses great challenges for realizing its clinical potentials. In the current study, octenyl succinic anhydride-modified starch (OSA-S), a renewable and biodegradable biopolymer, was employed to fabricate Cur amorphous composite nanoparticles (Cur/OSA-S NPs) through a solvent-free pH-driven method with the aim to enhance Cur's bioavailability by improving its solubility and stability. Cur/OSA-S NPs, with mean sizes of about 128.9 ± 8.6 nm, encapsulation efficiencies of about 90.0 %, and the drug loading capacities around 51.0 ± 0.2 %, were successfully prepared. Cur was found to be dispersed within the composite nanoparticles in amorphous state as confirmed by the XRD and DSC characterizations. In addition, Cur/OSA-S NPs offers excellent storage, thermal and light stability, excellent re-dispersibility, and approximately 92 times better solubility than the original Cur. Furthermore, studies of dissolution and the parallel artificial membrane permeability assay (PAMPA) confirmed enhanced dissolution rates and in vitro permeabilities of Cur/OSA-S NPs. Cancer cell viability and uptake experiments revealed that Cur/OSA-S NPs possessed more potent inhibitory effects on cancer cell proliferation compared to the raw Cur. The results obtained from the current study demonstrated the effectiveness of OSA-S for manufacturing Cur amorphous composite nanoparticles with enhanced solubility, stability, and permeability, which might be valuable for further development of Cur based products for treatment of various diseases.

Polysaccharide-Based Micro/Nanomotors for Active Ingredient Delivery in Food

Micro/nanomotors (MNMs) are miniature devices that can generate energy through chemical reactions or physical processes, utilizing this energy for movement. By virtue of their small size, self-propulsion, precise positioning within a small range, and ability to access microenvironments, MNMs have been applied in various fields including sensing, biomedical applications, and pollutant adsorption. However, the development of food-grade MNMs and their application in food delivery systems have been scarcely reported. Currently, there are various issues with the decomposition, oxidation, or inability to maintain the activity of some nutrients or bioactive substances, such as the limited application of curcumin (Cur) in food. Compared to traditional delivery systems, MNMs can adjust the transport speed and direction as needed, effectively protecting bioactive substances during delivery and achieving efficient transportation. Therefore, this study utilizes polysaccharides as the substrate, employing a simple, rapid, and pollution-free template method to prepare polysaccharide-based microtubes (PMTs) and polysaccharide-based micro/nanomotors (PMNMs). PMNMs can achieve multifunctional propulsion by modifying ferrosoferric oxide (Fe3O4), platinum (Pt), and glucose oxidase (GOx). Fe-PMNMs and Pt-PMNMs exhibit excellent photothermal conversion performance, showing promise for applications in photothermal therapy. Moreover, PMNMs can effectively deliver curcumin, achieving the effective delivery of nutrients and exerting the anti-inflammatory performance of the system.

Medicinal and chemosensing applications of chitosan based material: A review

Chitosan (CTS), has emerged as a highly intriguing biopolymer with widespread applications, drawing significant attention in various fields ranging from medicinal to chemosensing. Key characteristics of chitosan include solubility, biocompatibility, biodegradability and reactivity, making it versatile in numerous sectors. Several derivatives have been documented for their diverse therapeutic properties, such as antibacterial, antifungal, anti-diabetic, anti-inflammatory, anticancer and antioxidant activities. Furthermore, these compounds serve as highly sensitive and selective chemosensor for the detection of various analytes such as heavy metal ions, anions and various other species in agricultural, environmental and biological matrixes. CTS derivatives interacting with these species and give analytical signals. In this review, we embark on an exploration of the latest advancements in CTS-based materials, emphasizing their noteworthy contributions to medicinal chemistry spanning the years from 2021 to 2023. The intrinsic biological and physiological properties of CTS make it an ideal platform for designing materials that interact seamlessly with biological systems. The review also explores the utilization of chitosan-based materials for the development of colorimetric and fluorimetric chemosensors capable of detecting metal ions, anions and various other species, contributing to advancements in environmental monitoring, healthcare diagnostics, and industrial processes.

Exploring the link between pyrethroids exposure and dopaminergic degeneration through morphometric, immunofluorescence, and in-silico approaches: the therapeutic role of chitosan-encapsulated curcumin nanoparticles

Introduction: The synthetic pyrethroid derivative fenpropathrin (FNE), a commonly used insecticide, has been associated with various toxic effects in mammals, particularly neurotoxicity. The study addressed the hallmarks of the pathophysiology of Parkinson's disease upon oral exposure to fenpropathrin (FNE), mainly the alteration of dopaminergic markers, oxidative stress, and molecular docking in rat models. In addition, the protective effect of curcumin-encapsulated chitosan nanoparticles (CRM-Chs-NPs) was also assessed. Methods: In a 60-day trial, 40 male Sprague Dawley rats were divided into 4 groups: Control, CRM-Chs-NPs (curcumin-encapsulated chitosan nanoparticles), FNE (15 mg/kg bw), and FNE + CRM-Chs-NPs. Results: FNE exposure induced reactive oxygen species generation, ATP production disruption, activation of inflammatory and apoptotic pathways, mitochondrial function and dynamics impairment, neurotransmitter level perturbation, and mitophagy promotion in rat brains. Molecular docking analysis revealed that FNE interacts with key binding sites of dopamine synthesis and transport proteins. On the other hand, CRM-Chs-NPs mitigated FNE's toxic effects by enhancing mitochondrial dynamics, antioxidant activity, and ATP production and promoting anti-inflammatory and antiapoptotic responses. Conclusion: In summary, FNE appears to induce dopaminergic degeneration through various mechanisms, and CRM-Chs-NPs emerged as a potential therapeutic intervention for protecting the nervous tissue microenvironment.

Development and performance evaluation of self-assembled pH-responsive curcumin-bacterial exopolysaccharide micellar conjugates as bioactive delivery system

The present study reports the synthesis of micellar conjugates, wherein curcumin (Cur), a bioactive compound with poor bioavailability, was covalently bonded to a bacterial exopolysaccharide (EPS). These conjugates were synthesized by utilizing succinic acid that linked Cur to the pyranosyl moiety of the EPS. The Cur-EPS conjugates appeared as spherical micelles in aqueous solution and were found to have an average hydrodynamic diameter of 254 ± 2.7 nm. The micellar conjugates showed superior stability than Cur as evident from their negative surface charge (-27 ± 1.8 mV) and low polydispersity index (PDI) (0.33 ± 0.04). The in vitro studies on release kinetics helped elucidate the pH-responsive characteristics of the Cur-EPS conjugate, as 87.50 ± 1.45 % of Cur was released at an acidic pH of 5.6, in contrast to 30.15 ± 2.61 % at systemic pH of 7.4 at 150 h. The conjugates were hemocompatible and exhibited cytotoxic effect against the osteosarcoma cell line (MG-63) after 48 h treatment. They also demonstrated superior antibacterial, antibiofilm, and antioxidant activities in comparison to free Cur. Therefore, the Cur-EPS conjugates have potential pharmaceutical applications as therapeutic biomaterial that can be applied as a drug delivery system.

Oral Curcumin-Thioketal-Inulin Conjugate Micelles against Radiation-Induced Enteritis

Radiation-induced enteritis is an unavoidable complication associated with pelvic tumor radiotherapy, significantly influencing the prognosis of cancer patients. The limited availability of commercial gastrointestinal radioprotectors in clinical settings poses a substantial challenge in preventing radiation enteritis. Despite the inherent radioprotective characteristics of Cur in vitro, its poor solubility in water, instability, and low bioavailability lead to inferior therapeutic effects in vivo. Herein, we developed novel ROS-responsive micelles (CTI) from inulin and curcumin, aimed at mitigating radiation enteritis. CTI micelles had excellent solubility and stability. Importantly, CTI improved the cytotoxicity and bioavailability of curcumin, thereby showing enhanced effectiveness in neutralizing ROS induced by radiation, safeguarding against DNA damage, and reducing radiation-induced cellular mortality. Moreover, in a radiation enteritis mice model, CTI not only alleviated severe radiation-induced intestinal injury but also improved redox-related indicators and reduced inflammatory cytokine expression. Furthermore, CTI effectively increased gut microbiota abundance and maintained gut homeostasis. In conclusion, CTI could be a promising candidate for the clinical management of radiation enteritis. Our study provides a new perspective for radioprotection using natural antioxidants.

Effect of subcritical water temperature on the chain conformation and immune activity of ginger polysaccharides

In this study, the ginger polysaccharides extracted from hot water (HW-G) were modified with subcritical water (SW-G) to effectively regulate their immune activity, and the relationship between polysaccharide chain conformation and immune activity at different subcritical water temperatures was investigated. The results indicated that, compared with HW-G, the xylose and mannose were degraded at high temperatures. The molecular weight of ginger polysaccharide decreased from 1.083 × 106 g/mol to 3.113 × 105 g/mol after subcritical water modification (100-160 °C). The chain conformation transitioned from rigid rod chain to semi-rigid chain and eventually to random coil. The degree of relaxation of the polysaccharide chains showed a continuous increase trend. Additionally, ginger polysaccharide modified by subcritical water at 130 °C was found to promote the proliferation and phagocytosis of 264.7 cells more obviously and signally increase the secretion levels of NO, IL-6, TNF-α and IL-1β. When the subcritical water temperature exceeds 130 °C, the activity of ginger polysaccharide begins to decline rapidly. These findings demonstrate a close correlation between polysaccharide chain conformation and immunomodulatory activity, confirming the feasibility of the subcritical water temperature effect as a means of immune activity regulation, which opens up a new approach to obtaining highly active polysaccharides.

Effect of particle size of sesbania gum on its modification, structure and performances

Sesbania gum (SG), as an environmentally friendly and resourceful natural polymer, has attracted a lot of attention due to its favorable properties. The size distribution of SG powders was broadened owing to the growth. Therefore, it inevitably resulted in the differences in reaction activity, structure and properties of different SG particles. The results showed that small SG particles exhibited higher reaction activity in cross-linking, carboxymethylation and oxidation than its large counterparts. Compared with those of large SG particles, the sedimentation volume of small SG particles could be reduced by 1.1 mL, while their substitution degree of carboxymethyl groups and aldehyde content could be increased by 0.0824 and 18.11 %, respectively. The swelling capacity, freeze-thaw stability, acid and alkali resistance of small SG particles were greater than those of large SG particles, but their retrogradation was weaker than that of large counterparts. The crystalline degree of small SG particles consisting of more long molecular chains could be reduced by 9.8 % compared to large SG particles. The DSC curve of small SG particles was significantly different from that of large SG particles, while the difference in TGA curves between small particles and large particles was relatively small. The enthalpy change of small SG particle was reduced by 48.4 J/g compared to large SG particles. The peak viscosity, final viscosity, breakdown and setback of tapioca starch were obviously influenced by the addition of small SG particles. And their emulsification stability was also better than large SG particles.

Morphologically transformable peptide nanocarriers coloaded with doxorubicin and curcumin inhibit the growth and metastasis of hepatocellular carcinoma

In tumor treatment, the highly disordered vascular system and lack of accumulation of chemotherapeutic drugs in tumors severely limit the therapeutic role of nanocarriers. Smaller drug-containing nanoparticles (NPs) can better penetrate the tumor but are easily removed, which severely limits the tumor-killing properties of the drug. The chemotherapeutic medication doxorubicin (DOX) is highly toxic to the heart, but this toxicity can be effectively mitigated and the combined anticancer effect can be enhanced by clinically incorporating curcumin (CUR) as part of the dual therapy. We designed a small-molecule peptide, Pep1, containing a targeting peptide (CREKA) and a pH-responsive moiety. These NPs can target the blood vessels in tumor microthrombi and undergo a morphological shift in the tumor microenvironment. This process enhances the penetration and accumulation of drugs, ultimately improving the effectiveness of cancer treatment. In vitro and in vivo experiments demonstrated that this morphological transformation allowed rapid and effective drug release into tumors, the effective inhibition of tumor angiogenesis, and the promotion of tumor cell apoptosis, thus effectively killing tumor cells. Our findings provide a novel and simple approach to nhibit the growth and metastasis of hepatocellular carcinoma.

Effect of Hydrophobic Chain Length in Amphiphilic Chitosan Conjugates on Intracellular Drug Delivery and Smart Drug Release of Redox-Responsive Micelle

Three redox-sensitive nanocarriers were rationally designed based on amphiphilic low molecular weight chitosan-cystamine-octylamine/dodecylamin/cetylamine (LC-Cys-OA, LC-Cys-DA, LC-Cys-CA) conjugates containing disulfide linkage for maximizing therapeutic effect by regulating hydrophobic interaction. The resultant spherical micelles had the characteristics of low CMC, suitable size, excellent biosafety and desired stability. The drug-loaded micelles were fabricated by embedding doxorubicin (Dox) into the hydrophobic cores. The effect of hydrophobic chain lengths of amphiphilic conjugates on encapsulation capacity, redox sensitivity, trigger-release behavior, cellular uptake efficacy, antitumor effect and antimigratory activity of Dox-loaded micelles was systematically investigated. Studies found that Dox-loaded LC-Cys-CA micelle had superior loading capacity and enhanced redox sensitivity compared with the other two micelles. Release assay indicated that the three Dox-loaded micelles maintained sufficiently stability in normal blood circulation but rapidly disintegrated in tumor cells. More importantly, the LC-Cys-CA micelle with a longer hydrophobic chain length exhibited a higher accumulative Dox release percentage than the other two micelles. Additionally, an increase in hydrophobic chain lengths of amphiphilic conjugates improved cellular uptake efficiency, antitumor effect and antimigration activity of Dox-loaded micelles, which could be explained by enhanced loading ability and redox sensitivity. Our research was expected to provide a viable platform for achieving a desired therapeutic efficacy via the alteration of hydrophobic interaction.

Zwitterionic dendrimer self-assembled nanodrugs with high drug loading for enhanced anti-tumor ability

Zwitterionic dendrimers have been used to construct many nanomedicines due to their ability to achieve controlled drug release, but their low drug loading content limits their application in nanodrug delivery. To solve this problem, the surface of second generation polypropylimine (G2 PPI) was modified with mercapturized paclitaxel (PTX-SH) and zwitterionic groups to prepare zwitterionic prodrug molecule (PPIMPC), and then zwitterionic dendrimer self-assembled nanodrugs (PPIMPC-DOX micelles) were prepared by incorporating doxorubicin (DOX) into the micelles. The DOX loading and paclitaxel (PTX) loading in PPIMPC-DOX micelles was 6.7% and 26.2%, respectively, and the total drug loading of PPIMPC-DOX was high to 32.9%. In addition, PPIMPC-DOX micelles showed enhanced cytotoxicity due to improved cell uptake of DOX. More importantly, the inhibition rate of tumor was much higher than free DOX. The zwitterionic property and high drug loading of PPIMPC-DOX micelles enhanced anti-tumor ability of chemotherapeutic drugs. The method of preparation of zwitterionic and high drug loading of nanodrugs shows good application prospects in the future.

Stabilization of capsanthin in physically-connected hydrogels: Rheology property, self-recovering performance and syringe/screw-3D printing

This work presented a facile way of stabilizing capsanthin by physically-connected soft hydrogels via utilizing specially-structured polysaccharides, and investigated rheological properties, self-recovering mechanism and 3D printability. The functionalized hydrogels demonstrated excellent color quality including redness, yellowness index and hue with great storage stability and visual perception. The soft hydrogels fabricated with properly sequenced polyglyceryl fatty acid esters, β-cyclodextrin, chitosan, and low-content capsanthin possessed outstanding extrudability, appropriate yield stress, reasonable mechanical strength, rational elasticity and structure sustainability. Furthermore, the self-recovering properties based on hydrogen bonds, host-guest interactions and electrostatic interactions were revealed and verified by structural, zeta potential, micro-morphological, zeta potential, thixotropic, creep-recovery, and macroscopic/microscopic characterizations. Along with excellent antioxidant performance, the subsequent 3D printing onto bread with complex models elucidated the high geometry accuracy and great sensory characters. The sequenced physically-connected hydrogels incorporated with capsanthin can provide new insights on stabilizing hydrophobic biomaterials and developing the 3D printed exquisite, innovative food.

pH-sensitive biosystem based on laponite RD/chitosan/polyvinyl alcohol hydrogels for controlled delivery of curcumin to breast cancer cells

In this study, a pH-responsive hydrogels based on laponite rapid dispersion (Lap®)/chitosan (CS)/polyvinyl alcohol (PVA) designed and was used for controlled delivery of the anticancer drug curcumin (CUR). First, it was accomplished by dissolving CUR in Lap® dispersion under the influence of the pH of the environment. Then, in the presence of Lap®CUR cross-linking was incorporated between CS and PVA polymers. The structural features of Lap®CUR/CS@PVA hydrogels are characterized using FT-IR, XRD, SEM/EDS, TEM, TGA, Zeta potential, and XPS. The in vitro drug release profiles confirmed a pH-responsive controlled release of CUR in acidic pH for all hydrogels. During 12 h, the cumulative release of CUR from Lap®CUR/0.1CS@PVA hydrogel was 27.9% and 12.3%, at pH 5.5 and 7.4, respectively. While during three days the release rate reached 48.5% and 18.5%. The CUR release kinetic from hydrogels also suggests that the kinetic data well fitted to the Korsmeyer-Peppas, diffusion-controlled and Fickian diffusion. Furthermore, in vitro cytotoxicity and DAPI staining study clearly illustrated that Lap®CUR/0.1CS@PVA hydrogel had lower cytotoxicity than CUR against MDA-MB 231 cancer cells, which confirmed the controlled release of drug through hydrogels. Meanwhile, in vitro hemolysis, antioxidant and antibacterial tests revealed that the prepared hydrogels have good blood compatibility, excellent antioxidant properties, and antibacterial activity. Based on the obtained results, the designed hydrogels could be potentially applied as pH-controlled drug delivery systems for cancer therapy.

Wood structure-inspired injectable lignin-based nanogels as blood-vessel-embolic sustained drug-releasing stent for interventional therapies on liver cancer

An embolic reagent with easy injection, well-controlled target embolization, and sustained release of chemotherapy drugs is urgently needed for successful trans-arterial chemo-embolization (TACE) treatment. However, the development of a highly effective embolic reagent is still challenged. Here, inspired and guided by the structural supporting properties and defense mechanisms of wood cell walls, an ideal lignin-based embolic nanogel (DOX-pN-KL) was explored. Based on the mechanical support of branched lignin and the π-π stacking force between the lignin aromatic ring with anti-tumor drug doxorubicin (DOX), DOX-pN-KL showed the highest mechanical strength among the reported thermosensitive embolization nanogel and performed high drug-loading and favorable sustained-release. Moreover, further TACE treatment and tumor microenvironment evaluation of VX2 tumor-bearing rabbits showed that this nanogel can completely block all levels of vessels in long term and continuously release DOX, thus having effective inhibition on tumor growth and metastasis. DOX-pN-KL is expected to be a promising alternative reagent for interventional therapy.

Preparation of Self-Assembled, Curcumin-Loaded Nano-Micelles Using Quarternized Chitosan-Vanillin Imine (QCS-Vani Imine) Conjugate and Evaluation of Synergistic Anticancer Effect with Cisplatin

Nano-micelles are self-assembling colloidal dispersions applied to enhance the anticancer efficacy of chemotherapeutic agents. In this study, the conjugate of quarternized chitosan and vanillin imine (QCS-Vani imine) was synthesized using the reaction of a Schiff base characterized by proton-NMR (1HNMR), UV-Vis spectroscopy, and FT-IR. The critical micelle concentration (CMC), particle size, and zeta potential of the resulting product were determined. The QCS-Vani imine conjugate was used as a carrier for the development of curcumin-loaded nano-micelles, and their entrapment efficiency (%EE), drug-loading capacity (%LC) and in vitro release were investigated using HPLC analysis. Moreover, the nano-micelles containing curcumin were combined with various concentrations of cisplatin and evaluated for a possible anticancer synergistic effect. The anticancer activity was evaluated against lung cancer A549 and mouse fibroblast L929 cell lines. The percent yield (%) of the QCS-Vani imine conjugate was 93.18%. The curcumin-loaded QCS-Vani imine nano-micelles were characterized and found to have a spherical shape (by TEM) with size < 200 nm (by DLS) with high %EE up to 67.61% and %LC up to 6.15 ± 0.41%. The loaded lyophilized powder of the nano-micelles was more stable at 4 °C than at room temperature during 120 days of storage. pH-sensitive release properties were observed to have a higher curcumin release at pH 5.5 (cancer environment) than at pH 7.4 (systemic environment). Curcumin-loaded QCS-Vani imine nano-micelles showed higher cytotoxicity and selectivity toward lung cancer A549 cell lines and exhibited lower toxicity toward the normal cell (H9C2) than pure curcumin. Moreover, the curcumin-loaded QCS-Vani imine nano-micelles exhibited an enhanced property of inducing cell cycle arrest during the S-phase against A549 cells and showed prominently induced apoptosis in lung cancer cells compared to that with curcumin. The co-treatment of cisplatin with curcumin-loaded QCS-Vani imine nano-micelles presented an enhanced anticancer effect, showing 8.66 ± 0.88 μM as the IC50 value, in comparison to the treatment with cisplatin alone (14.22 ± 1.01 μM). These findings suggest that the developed QCS-Vani imine nano-micelle is a potential drug delivery system and could be a promising approach for treating lung cancer in combination with cisplatin.

Simple Non-Equilibrium Atmospheric Plasma Post-Treatment Strategy for Surface Coating of Digital Light Processed 3D-Printed Vanillin-Based Schiff-Base Thermosets

A simple non-equilibrium atmospheric plasma post-treatment strategy was developed for the surface coating of three-dimensional (3D) structures produced by digital light processing 3D printing. The influence of non-equilibrium atmospheric plasma on the chemical and physical properties of vanillin-derived Schiff-base thermosets and the dip-coating process was investigated and compared to the influence of traditional post-treatment with UV-light. As a comparison, thermosets without post-treatment were also subjected to the coating procedure. The results document that UV post-treatment can induce the completion of the curing of the printed thermosets if complete curing is not reached during printing. Conversely, the plasma post-treatment does not contribute to the curing of the thermoset but causes some opening of the imine bonds and the regeneration of aldehyde functions. As a consequence, no great differences are observed between the not post-treated and plasma post-treated samples in terms of mechanical, thermal, and solvent-resistant properties. In contrast to the UV post-treatment, the plasma post-treatment of the thermosets induces a noticeable increase of the thermoset hydrophilicity ascribed to the reformation of amines on the thermoset surface. The successful coating process and the greatest uniformity of the lignosulfonate coating on the surface of plasma post-treated samples are considered to be due to the presence of these amines and aldehydes. The investigation of the UV shielding properties and antioxidant activities documents the increase of both properties with the increasing amount and uniformity of the formed coating. Interestingly, evident antioxidant properties are also shown by the noncoated thermosets, which are deduced to their chemical structures.

Precursor template-induced egg white-derived peptides self-assembly for the enhancement of curcumin: Structure, environmental stability, and bioavailability

Natural multicomponent peptides with abundant bioactivity, varied sizes, and tunable interaction potential are available for rational designing novel self-assembled delivery carriers. Herein, we exploited zein-hyaluronic acid nanoparticles (Z-HA NPs) with a predetermined ordered structure as precursor templates to induce the self-assembly of egg white-derived peptides (EWDP) to generate stable spherical architectures for the enhancement of curcumin (Cur). The resulting Z-EWDP-HA NPs encapsulated hydrophobic Cur through robust hydrogen bonding and hydrophobic interactions with high encapsulation efficiency (97.38% at pH 7.0). The NPs presented superior Cur aqueous solubility, redispersibility, and photothermal stability. More importantly, the self-assembled EWDP could exert synergistic antioxidant activity with Cur and enhance the bioaccessibility of Cur. Meanwhile, the favorable biocompatibility and membrane affinity of EWDP further prolonged residence and time-controlled release feature of Cur in the small intestine. Precursor template-induced multicomponent peptides' self-assembly provides an efficient and controllable strategy for co-enhanced bioactivity and self-assembly capacity of peptides, which could dramatically broaden the functionalization of multicomponent peptides hydrolyzed from natural food proteins.

Liposomes Co-Delivering Curcumin and Colistin to Overcome Colistin Resistance in Bacterial Infections

Antibiotic colistin is the last line of defense against multidrug-resistant (MDR) Gram-negative bacterial infections. Emergence of colistin resistance in microbes is a critical challenge. Herein, curcumin is discovered, for the first time, to reverse the resistance phenotype of colistin-resistant bacteria via a checkerboard assay. For the co-delivery of curcumin and colistin, negatively charged poly(ethylene glycol)-functionalized liposomes encapsulating both drugs (Lipo-cc) are prepared. Killing kinetics and live/dead assays confirm the antibacterial activity of Lipo-cc against colistin-resistant bacteria, which is more potent than that of the free curcumin and colistin combination. Mechanistical studies reveal that Lipo-cc restores the affinity of colistin for the bacterial membrane and improves the uptake of curcumin, which leads to reduced efflux pump activity, achieving a synergistic effect of colistin and curcumin. At the effective antibacterial dose, Lipo-cc does not exhibit any toxicity. The therapeutic efficacy of Lipo-cc is further demonstrated in an intestinal bacterial infection model induced with colistin-resistant Escherichia coli. Lipo-cc reduces the bacterial burden with over 6-log reduction and alleviated inflammation caused by infection. Importantly, unlike colistin, Lipo-cc does not affect the homeostasis of the intestinal flora. Taken together, Lipo-cc successfully overcame colistin resistance, indicating its potential for the treatment of colistin-resistant bacterial infections.

Redox-sensitive self-assembled micelles based on low molecular weight chitosan-lipoic acid conjugates for the delivery of doxorubicin: Effect of substitution degree of lipoic acid

Amphiphilic low molecular weight chitosan-lipoic acid (LC-LA) conjugates with different degrees of substitution (DS) of LA were synthesized by N, N'‑carbonyldiimidazole (CDI) catalysis to self-assemble into redox-sensitive micelles. Critical micelle concentration (CMC), size, zeta potential, biocompatibility and redox-sensitive behavior of blank micelles were investigated. The results indicated that blank micelles with low CMC, nanoscale size and positive zeta potential showed excellent biocompatibility and redox-sensitive behavior. Doxorubicin (Dox) loaded micelles were prepared by encapsulating Dox into blank micelles. The loading ability, trigger-release behavior, antitumor activity and cellular uptake of Dox loaded micelles were studied. The results demonstrated that Dox loaded micelles with superior loading ability exhibited redox-trigger behavior, strong antitumor activity and increased cellular uptake efficiency against A549 cell. Besides, the effect of DS of LA on above properties was estimated. An increase in DS of LA reduced the CMC and cumulative release amount of Dox, but improved the loading efficiency, antitumor activity, and cellular uptake of Dox loaded micelles, which resulted from stronger interaction of hydrophobic groups in micelles with the DS of LA increased. Overall, self-assembled LC-LA micelles with good biosecurity and redox-sensitive behavior hold promising application prospects in Dox delivery and improving cancer therapeutic effect of Dox.

Fluorescent Probes with Förster Resonance Energy Transfer Function for Monitoring the Gelation and Formation of Nanoparticles Based on Chitosan Copolymers

Nanogel-forming polymers such as chitosan and alginic acid have a number of practical applications in the fields of drug delivery, food technology and agrotechnology as biocompatible, biodegradable polymers. Unlike bulk macrogel formation, which is followed by visually or easily detectable changes and physical parameters, such as viscosity or turbidity, the formation of nanogels is not followed by such changes and is therefore very difficult to track. The counterflow extrusion method (or analogues) enables gel nanoparticle formation for certain polymers, including chitosan and its derivatives. DLS or TEM, which are typically used for their characterization, only allow for the study of the already-formed nanoparticles. Alternatively, one might introduce a fluorescent dye into the gel-forming polymer, with the purpose of monitoring the effect of its microenvironment on the fluorescence spectra. But apparently, this approach does not provide a sufficiently specific signal, as the microenvironment may be affected by a big number of various factors (such as pH changes) including but not limited to gel formation per se. Here, we propose a new approach, based on the FRET effect, which we believe is much more specific and enables the elucidation of nanogel formation process in real time. Tryptophan-Pyrene is suggested as one of the donor-acceptor pairs, yielding the FRET effect when the two compounds are in close proximity to one another. We covalently attached Pyrene (the acceptor) to the chitosan (or PEG-chitosan) polymeric chain. The amount of introduced Pyrene was low enough to produce no significant effect on the properties of the resulting gel nanoparticles, but high enough to detect the FRET effect upon its interaction with Trp. When the Pyr-modified chitosan and Trp are both present in the solution, no FRET effect is observed. But as soon as the gel formation is initiated using the counterflow extrusion method, the FRET effect is easily detectable, manifested in a sharp increase in the fluorescence intensity of the pyrene acceptor and reflecting the gel formation process in real time. Apparently, the gel formation promotes the Trp-Pyr stacking interaction, which is deemed necessary for the FRET effect, and which does not occur in the solution. Further, we observed a similar FRET effect when the chitosan gel formation is a result of the covalent crosslinking of chitosan chains with genipin. Interestingly, using ovalbumin, having numerous Trp exposed on the protein surface instead of individual Trp yields a FRET effect similar to Trp. In all cases, we were able to detect the pH-, concentration- and temperature-dependent behaviors of the polymers as well as the kinetics of the gel formation for both nanogels and macrogels. These findings indicate a broad applicability of FRET-based analysis in biomedical practice, ranging from the optimization of gel formation to the encapsulation of therapeutic agents to food and biomedical technologies.

Modified porous starches loading curcumin and improving the free radical scavenging ability and release properties of curcumin

Maize porous starch-curcumin microspheres were prepared by encapsulating curcumin into cross-linked porous starch and oxidized porous starch to investigate the effect of modified porous starch in embedding and protecting curcumin. The morphology and physicochemical properties of microspheres were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, Zeta/DLS, Thermal stability, and antioxidant activity; the release of curcumin was evaluated with a simulated gastric-intestine model. The FT-IR results revealed that curcumin was amorphously encapsulated in the composite and hydrogen bond formation between starch and curcumin was one of the major driving forces for encapsulation. Microspheres increased the initial decomposition temperature of curcumin, which has a protective effect on curcumin. Modification improved the encapsulation efficiency and the scavenging free radical ability of porous starch. The release mechanism of curcumin from microspheres fits first-order and Higuchi models well in gastric and intestinal models, respectively, indicating that encapsulation of curcumin within different porous starches microspheres enables controlled release of curcumin. To recapitulate, two different modified porous starch microspheres improved the drug loading, slow release and free radical scavenging effects of curcumin. Among them, the cross-linked porous starch microspheres had higher encapsulation and slow release ability for curcumin than the oxidized porous starch microspheres. It provides theoretical significance and data basis for the encapsulation of active substances by modified porous starch.

Polymeric Micelles Formulation of Combretastatin Derivatives with Enhanced Solubility, Cytostatic Activity and Selectivity against Cancer Cells

Combretastatin derivatives is a promising class of antitumor agents, tubulin assembly inhibitors. However, due to poor solubility and insufficient selectivity to tumor cells, we believe, their therapeutic potential has not been fully realized yet. This paper describes polymeric micelles based on chitosan (a polycation that causes pH and thermosensitivity of micelles) and fatty acids (stearic, lipoic, oleic and mercaptoundecanoic), which were used as a carrier for a range of combretastatin derivatives and reference organic compounds, demonstrating otherwise impossible delivery to tumor cells, at the same time substantially reduced penetration into normal cells. Polymers containing sulfur atoms in hydrophobic tails form micelles with a zeta potential of about 30 mV, which increases to 40-45 mV when cytostatics are loaded. Polymers with tails of oleic and stearic acids form poorly charged micelles. The use of polymeric 400 nm micelles provides the dissolution of hydrophobic potential drug molecules. Micelles could significantly increase the selectivity of cytostatics against tumors, which has been shown using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, Fourier transform infrared (FTIR) spectroscopy, flow cytometry and fluorescence microscopy. Atomic force microscopy presented the difference between the unloaded micelles and those loaded with the drug: the size of the former was 30 nm on average, while the latter had a "disc-like" shape and a size of about 450 nm. The loading of drugs into the core of micelles was confirmed by UV and fluorescence spectroscopy methods; shifts of absorption and emission maxima into the long-wavelength region by tens of nm was observed. With FTIR spectroscopy, a high interaction efficiency of micelles with the drug on cells was demonstrated, but at the same time, selective absorption was observed: micellar cytostatics penetrate into A549 cancer cells 1.5-2 times better than the simple form of the drugs. Moreover, in normal HEK293T, the penetration of the drug is reduced. The proposed mechanism for reducing the accumulation of drugs in normal cells is the adsorption of micelles on the cell surface and the preservation of cytostatics to penetrate inside the cells. At the same time, in cancer cells, due to the structural features of the micelles, they penetrate inside, merging with the membrane and releasing the drug by pH- and glutathione-sensitive mechanisms. From a methodological point of view, we have proposed a powerful approach to the observation of micelles using a flow cytometer, which, in addition, allows us to quantify the cells that have absorbed/adsorbed cytostatic fluorophore and distinguish between specific and non-specific binding. Thus, we present polymeric micelles as drug delivery systems in tumors using the example of combretastatin derivatives and model fluorophore-cytostatic rhodamine 6G.

Biological characterization of microwave based synthesized ZnO and Ce doped ZnO nanoflowers impeded chitosan matrix with enhanced antioxidant and anti-diabetic properties

The chitosan matrix was used as a substrate for ZnO nanoflowers (ZnO/CH) and Ce-doped ZnO nanoflowers (Ce-ZnO/CH) by microwave-induced hydrothermal synthesis processes. The obtained hybrid structures were assessed as enhanced antioxidant and antidiabetic agents considering the synergetic effect of the different components. The integration of chitosan and cerium induced significantly the biological activity of ZnO flower-like particles. Ce-doped ZnO nano-flowers show higher activities than both ZnO nanoflowers and ZnO/CH composite reflecting the strong effect of surface electrons that were formed by the doping process as compared to the high interactive interface of the chitosan substrate. As an antioxidant the synthetic Ce-ZnO/CH composite achieved remarkable scavenging efficiencies for DPPH (92.4 ± 1.33 %), nitric oxide (95.2 ± 1.81 %), ABTS (90.4 ± 1.64 %), and superoxide (52.8 ± 1.22 %) radicals which are significantly higher values than Ascorbic acid as standard and the commercially used ZnO nanoparticles. Also, its antidiabetic efficiency enhanced greatly achieving strong inhibition effects on porcine α-amylase (93.6 ± 1.66 %), crude α-amylase (88.7 ± 1.82 %), pancreatic α-glucosidase (98.7 ± 1.26 %), crude intestinal α-glucosidase (96.8 ± 1.16 %), and amyloglucosidase (97.2 ± 1.72 %) enzymes. The recognized inhibition percentages are notably higher than the determined percentages using miglitol drug and slightly higher than acarbose. This recommends the Ce-ZnO/CH composite as a potential antidiabetic and antioxidant agent compared with the high cost and the reported side effects of the commonly used chemical drug.

Synthesis and Biological Activity Evaluations of Green ZnO-Decorated Acid-Activated Bentonite-Mediated Curcumin Extract (ZnO@CU/BE) as Antioxidant and Antidiabetic Agents

Green ZnO-decorated acid-activated bentonite-mediated curcumin extract (ZnO@CU/BE) was prepared as a multifunctional antioxidant and antidiabetic agent based on the extract of curcumin, which was used as a reducing and capping reagent. ZnO@CU/BE showed notably enhanced antioxidant properties against nitric oxide (88.6 ± 1.58%), 1,1-diphenyl-2-picrylhydrazil (90.2 ± 1.76%), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (87.3 ± 1.61%), and superoxide (39.5 ± 1.12%) radicals. These percentages are higher than the reported values of ascorbic acid as a standard and the integrated components of the structure (CU, BE/CU, and ZnO). This signifies the impact of the bentonite substrate on enhancing the solubility, stability, dispersion, and release rate of the intercalated curcumin-based phytochemicals, in addition to enhancing the exposure interface of ZnO nanoparticles. Therefore, effective antidiabetic properties were observed, with significant inhibition effects on porcine pancreatic α-amylase (76.8 ± 1.87%), murine pancreatic α-amylase (56.5 ± 1.67%), pancreatic α-glucosidase (96.5 ± 1.07%), murine intestinal α-glucosidase (92.5 ± 1.10%), and amyloglucosidase (93.7 ± 1.55%) enzymes. These values are higher than those determined using commercial miglitol and are close to the values measured using acarbose. Hence, the structure can be applied as an antioxidant and antidiabetic agent.

Smart pH- and Temperature-Sensitive Micelles Based on Chitosan Grafted with Fatty Acids to Increase the Efficiency and Selectivity of Doxorubicin and Its Adjuvant Regarding the Tumor Cells

The main factors that determine the low effectiveness of chemotherapy are the low target bioavailability of antitumor drugs and the efflux process. In attempts to overcome this problem, several approaches are proposed here. Firstly, the development of polymeric micellar systems based on chitosan grafted by fatty acids (different types to optimize their properties), which, on the one hand, increase the solubility and bioavailability of cytostatics and, on the other hand, effectively interact with tumor cells due to the polycationic properties of chitosan, allowing for more effective penetration of cytostatic drugs into the cells. Secondly, the use of adjuvants-synergists of cytostatics (such as eugenol) included in the same micellar formulation-that selectively enhance the accumulation and retention of cytostatics in the tumor cells. pH- and temperature-sensitive polymeric micelles developed show high entrapment efficiency for both cytostatics and eugenol (EG) >60% and release the drug in a prolonged manner for 40 h in a weakly acidic medium corresponding to the microenvironment of tumors. In a slightly alkaline environment, the drug circulates longer (more than 60 h). The thermal sensitivity of micelles is realized due to an increase in the molecular mobility of chitosan, which undergoes a phase transition at 32-37 °C. The effect of the cytostatic drug doxorubicin (Dox) on cancerous A549 cells and model healthy cells of human embryonic renal epithelium (HEK293T) was studied by FTIR spectroscopy and fluorescence microscopy. Micellar Dox penetrates into cancer cells 2-3 times more efficiently when using EG adjuvant, which inhibits efflux, as demonstrated by a significant increase in the ratio of intra- and extracellular concentrations of the cytostatic. However, here it is worth remembering about healthy cells that they should not be damaged: according to changes in the FTIR and fluorescence spectra, the penetration of Dox into HEK293T when using micelles in combination with EG is reduced by 20-30% compared to a simple cytostatic. Thus, experimental developments of combined micellar cytostatic drugs have been proposed to increase the effectiveness of cancer treatment and overcome multiple drug resistance.

Synthesis and Characterization of Green Zinc-Metal-Pillared Bentonite Mediated Curcumin Extract (Zn@CN/BE) as an Enhanced Antioxidant and Anti-Diabetes Agent

Green zinc-metal-pillared bentonite mediated curcumin extract (Zn@CN/BE) was synthesized and characterized as a low-cost and multifunctional (curcumin-based phytochemicals, zinc-capped curcumin, zinc/curcumin complexes, and zinc-pillared bentonite) antioxidant and antidiabetic agent with enhanced activity. The activities of the Zn@CN/BE structure were assessed in comparison with curcumin and ZnO as individual components and in the presence of miglitol and acarbose commercial drugs as controls. The structure validated remarkable antioxidant activities against the common oxidizing radicals (nitric oxide (94.7 ± 1.83%), DPPH (96.4 ± 1.63%), ABTS (92.8 ± 1.33%), and superoxide (62.3 ± 1.63 %)) and inhibition activities against the main oxidizing enzymes (porcine α-amylase (89.3 ± 1.13%), murine α-amylase (70.8 ± 1.54%), pancreatic α-Glucosidase (99.3 ± 1.23%), intestinal α-Glucosidase (97.7 ± 1.24%), and amyloglucosidase (98.4 ± 1.64%)). The reported activities are higher than the activities of individual components and the studied ascorbic acid as well as the commercial drugs. This enhancement effect was assigned to the impact of the zinc pillaring process within the curcumin/bentonite host, which induced the stability, dispersions, and interactive interface of the essential active compounds in addition to the solubility and release rate of the intercalated curcumin extract. This paper recommends the application of the Zn@CN/BE structure as an enhanced, low-cost, biocompatible, safe, and simply produced antioxidant and antidiabetic agent.

Evaluation of Low-Toxic Hybrid Sol-Gel Coatings with Organic pH-Sensitive Inhibitors for Corrosion Protection of AA2024 Aluminium Alloy

Today’s environmental needs require the reduction of the weight of vehicles, thus reducing fuel consumption and associated emissions. For this reason, the use of light alloys is being studied, which, due to their reactivity, must be protected before use. In this work, the effectiveness of a hybrid sol-gel coating doped with various organic environmentally friendly corrosion inhibitors applied to an AA2024 lightweight aluminium alloy is evaluated. Some of the inhibitors tested are pH indicators, acting as both corrosion inhibitors and optical sensors for the surface of the alloy. Samples are subjected to a corrosion test in a simulated saline environment and characterised before and after the test. The experimental results regarding their best inhibitor performance for their potential application in the transport industry are evaluated.

Self-assembled emulsion gel based on modified chitosan and gelatin: Anti-inflammatory and improving cellular uptake of lipid-soluble actives

To obtain a green carrier for intestinal targeted delivery, an emulsion gel was designed by the self-assembly between gelatin and Pickering emulsion based on gallic acid modified-chitosan nanoparticles (GCS NPs). The emulsion gels loaded with garlic essential oil (Geo) and curcumin (Cur) were abbreviated as GOEG and GCEG, respectively. Meanwhile, the sodium alginate bead loaded with Geo (GOEGS₃) and the bead loaded with Cur (GCEGS) were prepared as controls. Results demonstrated that the emulsion gels significantly improved the bioaccessibility of Geo and Cur, showing great intestinal targeting delivery properties comparable to that of sodium alginate beads. Moreover, Caco-2 cell experiments indicated that GOEG and GCEG displayed good biocompatibility and enhanced cellular uptake of Geo and Cur. The emulsion gels also exhibited excellent anti-inflammatory properties in the lipopolysaccharide-induced cell model, exhibiting great potential for clinical application. This work provides some references for the preparation of multifunctional emulsion gels with excellent delivery performance by a green method.

Facile preparation of cellulose/lignosulfonate derivatives composite films with high UV-shielding and gas barrier properties

Herein, a serial of full cellulose and lignosulfonate derivatives (LS), including sodium lignosulfonate (LSS), calcium lignosulfonate (LSC), lignosulfonic acid (LSA), composite films were generated through dissolving cellulose in reversible carbon dioxide (CO₂) ionic liquids solvent system (TMG/EG/DMSO/CO₂ solvent system), followed by a facile solution-gelation transition and absorption strategy. The findings indicated that LS aggregated and embedded inside the cellulose matrix via H-bond interaction. The cellulose/LS derivatives composite films showed good mechanical properties which the tensile strength reaches the maximum value of 94.7 MPa in MCC3LSS film. While for the MCC1LSS film, the breaking strain increases to 11.6 %. The outstanding UV shielding effect and high transmittance in the visible region of composite films were also achieved and the shielding performance of the whole UV region (200-400 nm) tended to 100 % for MCC5LSS film. In addition, thiol-ene click reaction was selected as model reaction to verify the UV-shielding performance. It was also found that the oxygen and water vapor barrier performances of composite films were evidently associated with the intense H-bond interaction and tortuous path effect. The OP and WVP of MCC5LSS film were 0 and 6 × 10^-3 g·μm/m²·day·kPa, respectively. These outstanding properties make them with great potential for packaging field.

Novel hierarchical carbon microspheres@layered double hydroxides@copper lignosulfonate architecture for polypropylene with enhanced flame retardant and mechanical performances

Due to the inherent defect of flammability of polypropylene (PP), a novel and highly efficient carbon microspheres@layered double hydroxides@copper lignosulfonate (CMSs@LDHs@CLS) flame retardant was designed and prepared, which was attributed to the strong electrostatic interaction between carbon microspheres (CMSs), layered double hydroxides (LDHs) and lignosulfonate as well as the chelation effect of lignosulfonate on copper ions, and then it was incorporated into the PP matrix. Significantly, CMSs@LDHs@CLS not only observably improved its dispersibility in PP matrix, but also simultaneously achieved excellent flame retardant properties for composites. With the addition of 20.0 % CMSs@LDHs@CLS, the limit oxygen index of CMSs@LDHs@CLS and PP composites (PP/CMSs@LDHs@CLS) reached 29.3 % and achieved the UL-94 V-0 rating. Cone calorimeter tests indicated that the peak heat release rate, total heat release and total smoke production of PP/CMSs@LDHs@CLS composites exhibited declines of 28.8 %, 29.2 % and 11.5 %, respectively, compared with those of PP/CMSs@LDHs composites. These advancements were attributed to the better dispersibility of CMSs@LDHs@CLS in PP matrix and illustrated that CMSs@LDHs@CLS observably reduced fire hazards of PP. The flame retardant property of CMSs@LDHs@CLS might relate to condensed phase flame retardant effect of char layer and catalytic charring of copper oxides.

Development of Computational In Silico Model for Nano Lipid Carrier Formulation of Curcumin

The oral delivery system is very important and plays a significant role in increasing the solubility of drugs, which eventually will increase their absorption by the digestive system and enhance the drug bioactivity. This study was conducted to synthesize a novel curcumin nano lipid carrier (NLC) and use it as a drug carrier with the help of computational molecular docking to investigate its solubility in different solid and liquid lipids to choose the optimum lipids candidate for the NLCs formulation and avoid the ordinary methods that consume more time, materials, cost, and efforts during laboratory experiments. The antiviral activity of the formed curcumin-NLC against SARS-CoV-2 (COVID-19) was assessed through a molecular docking study of curcumin's affinity towards the host cell receptors. The novel curcumin drug carrier was synthesized as NLC using a hot and high-pressure homogenization method. Twenty different compositions of the drug carrier (curcumin nano lipid) were synthesized and characterized using different physicochemical techniques such as UV-Vis, FTIR, DSC, XRD, particle size, the zeta potential, and AFM. The in vitro and ex vivo studies were also conducted to test the solubility and the permeability of the 20 curcumin-NLC formulations. The NLC as a drug carrier shows an enormous enhancement in the solubility and permeability of the drug.

Nanoparticles Based on Chondroitin Sulfate from Tuna Heads and Chitooligosaccharides for Enhanced Water Solubility and Sustained Release of Curcumin

This study aimed to separate chondroitin sulfate (CS) from the heads of skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares), by-products derived from canned tuna processing, via a biological process. The use of 1% w/w papain and an incubation time of 48 h resulted in a degree of hydrolysis of 93.75 ± 2.94% and a CS content of 59.53 ± 1.77 mg/100 g. The FTIR spectra of extracted CS products exhibited identical functional groups found in commercially available CS. The molecular weights of CS extracted from skipjack and yellowfin tuna heads were 11.0 kDa and 7.7 kDa, respectively. Subsequently, a CH:CS ratio of 3:2 for CS and chitooligosaccharides (CH) was chosen as the optimal ratio for the preparation of spherical nanoparticles, with %EE, mean particle size, PDI, and zeta potential values of 50.89 ± 0.66%, 128.90 ± 3.29 nm, 0.27 ± 0.04, and -12.47 ± 2.06, respectively. The CU content was enhanced to 127.21 ± 1.66 μg/mL. The release of CU from this particular nanosystem involved mainly a drug diffusion mechanism, with a burst release in the first 3 h followed by a sustained release of CU over 24 h. The DPPH and ABTS scavenging activity results confirmed the efficient encapsulation of CU into CHCS nanoparticles. This study will provide a theoretical basis for CS derived from tuna head cartilages to be used as a functional component with specific functional properties in food and biomedical applications.

Design of glucono-δ-lactone-induced pinto bean protein isolate/κ-carrageenan mixed gels with various microstructures: fabrication, characterization, and release behavior

BACKGROUND

Protein gels are used for different purposes, such as providing good texture, serving as fat replacers, and enhancing the nutritional and functional characteristics of foods. They can also deliver controlled release agents for sensitive drugs. The objective of this study was to investigate the impact of κ-carrageenan (kcr) concentration (0, 1.5, 3, and 4.5 mg g^-1 ) on the morphological and physicochemical properties and release behavior of glucono-δ-lactone (GDL)-induced pinto bean protein aggregate (PBA) gels.

RESULTS

When κ-carrageenan concentration increased from 0 to 1.5 and 3 mg.g^-1 , the firmness of the samples increased significantly, by 2.04 and 3.7 fold, respectively (P < 0.05). A compact and homogenous network with considerable strength and maximum water-holding capacity (97.52 ± 1.17%) was obtained with the addition of 3 mg g^-1 κ-carrageenan to the gel system. Further increasing the κ-carrageenan concentration to 4.5 mg g^-1 produced a coarse gel structure with higher storage modulus (G'), firmness (6.30-fold), thermal stability, and entrapment efficiency (85.6%). Depending on the κ-carrageenan concentration, various microstructures from protein continuous phase to κ-carrageenan continuous phase were observed. The release test indicated that 70.25% of the loaded curcumin was released in the simulated gastrointestinal tract for pure PBA gels. In contrast, for binary gels containing 4.5 mg g^-1 κ-carrageenan, curcumin was protected in the upper gastrointestinal tract, and 64.45% of loaded curcumin was delivered to the colon.

CONCLUSION

Our study showed that κ-carrageenan/PBA gels had high entrapment efficiency and could protect curcumin in the upper gastrointestinal tract. The hydrogels are therefore very valuable for colon-targeting delivery purposes. © 2022 Society of Chemical Industry.

Synthesis and Characterization of Thermally Stable Lignosulfonamides

Lignin, a highly aromatic macromolecule building plant cells, and cellulose are two of the most commonly occurring natural polymers. Lignosulfonate is a grade of technical lignin, obtained as a by-product in the paper and wood pulping industries, a result of the used lignin isolation method, i.e., sulfite process. In this work, sodium lignosulfonate is used as a starting material to manufacture sulfonamide derivatives of lignin in a two-step modification procedure. Since this direction of the lignin modification is rather rarely investigated and discussed, it makes a good starting point to expand the state of knowledge and explore the properties of lignosulfonamides. Materials obtained after modification underwent characterization by FTIR, SS-NMR, WAXD, SEM, and TGA. Spectroscopic measurements confirmed the incorporation of dihexylamine into the lignin structure and the formation of lignosulfonamide. The crystalline structure of the material was not affected by the modification procedure, as evidenced by the WAXD, with only minute morphological changes of the surface visible on the SEM imaging. The obtained materials were characterized by improved parameters of thermal stability in relation to the raw material. As-prepared sulfonamide lignin derivatives with a potential application as a filler in biopolymeric composites may become a new class of functional, value-added, sustainable additives.