Preparation and Properties of Crosslinked Quaternized Chitosan-Based Hydrogel Films Ionically Bonded with Acetylsalicylic Acid for Biomedical Materials.

The aim of the current study is to develop chitosan-based biomaterials which can sustainably release acetylsalicylic acid while presenting significant biological activity. Herein, an innovative ionic bonding strategy between hydroxypropyl trimethyl ammonium chloride chitosan (HACC) and acetylsalicylic acid (AA) was proposed, skillfully utilizing the electrostatic attraction of the ionic bond to achieve the controlled release of drugs. Based on this point, six crosslinked -[(2-hydroxy-3-trimethylammonium)propyl]chitosan acetylsalicylic acid salt (CHACAA) hydrogel films with varying acetylsalicylic acid contents were prepared by a crosslinking reaction.

Synthesis and characterization of novel carboxymethyl inulin derivatives bearing cationic Schiff bases with antioxidant potential.

This study aimed to enhance the antioxidant activity of carboxymethyl inulin (CMI) by chemical modification. Therefore, a series of cationic Schiff bases bearing heteroatoms were synthesized and incorporated into CMI via ion exchange reactions, ultimately preparing 10 novel CMI derivatives (CMID). Their structures were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy.

Low molecular weight chitosan based GSH-responsive self-assembled cationic micelle with enhanced anti-tumor effect by combining oxidative damage and chemotherapy.

A novel cationic lipoic acid grafted low molecular weight chitosan (LCNE-LA) conjugate was constructed and further self-assembled into GSH-responsive cationic nanocarrier to achieve better antitumor effect by combining encapsulated chemotherapy and oxidative damage induced by ROS. The resultant LCNE-LA cationic micelle exhibited favorable physicochemical properties (low CMC, small size, positively zeta potential and good stability), excellent biosafety and desired redox sensitivity. Next, doxorubicin (Dox) was embedded into hydrophobic core to form stable Dox/LCNE-LA micelle that had superior loading capacity.

A novel chitosan antioxidant bearing sulfhydryl group: Synthesis, characterization and activity assessment.

To improve the antioxidant activity, sulfhydryl groups (-SH) were introduced into chitosan. Acylated chitosan derivatives, chitosan cationic salt derivatives, hydroxypropyl trimethylammonium chloride chitosan quaternary ammonium salt (HACC) derivatives and N,N,N-trimethyl chitosan iodine (TMC) derivatives were obtained. The chitosan derivatives were characterized by FTIR and H NMR to confirm the successful synthesis.

Improvement of the Antioxidant and Antitumor Activities of Benzimidazole-Chitosan Quaternary Ammonium Salt on Drug Delivery Nanogels.

The present study focused on the design and preparation of acid-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for a controlled, slow-release of Doxorubicin HCl (DOX.HCl). The BIMIXHAC was crosslinked with sodium tripolyphosphate (TPP) using the ion crosslinking method.

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.

pH-responsive nanogels with enhanced antioxidant and antitumor activities on drug delivery and smart drug release.

pH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method.

Phenolic Acid Functional Quaternized Chitooligosaccharide Derivatives: Preparation, Characterization, Antioxidant, Antibacterial, and Antifungal Activity.

As a promising biological material, chitooligosaccharide (COS) has attracted increasing attention because of its unique biological activities. In this study, fourteen novel phenolic acid functional COS derivatives were successfully prepared using two facile methods. The structures of derivatives were characterized by FT-IR and H NMR spectra.

Enhanced biological activities of coumarin-functionalized polysaccharide derivatives: Chemical modification and activity assessment.

Natural polysaccharides are abundant and renewable resource, but their applications are hampered by limited biological activity. Chemical modification can overcome these drawbacks by altering their structure. Three series of polysaccharide derivatives with coumarins were synthesized to obtain polysaccharide derivatives with enhanced biological activity.

Self-assembled low molecular weight chitosan-based cationic micelle for improved water solubility, stability and sustained release of α-tocopherol.

New amphiphilic low molecular weight chitosan-graft-nicotinic acid bearing decyl groups (LCND) was synthesized by two-step reaction and spontaneously assembled into cationic micelle by ultra-sonication method to improve water solubility and photostability properties of α-tocopherol. The chemical structure of LCND was characterized and physical properties of cationic micelle were evaluated. Results displayed that cationic micelle exhibited strong self-assemble ability with nanoscale spherical morphology and showed best loading ability with loading content of 18.

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.

Preparation of imidazole acids grafted chitosan with enhanced antioxidant, antibacterial and antitumor activities.

Herein, imidazole acids grafted chitosan derivatives were synthesized, including HACC, HACC derivatives, TMC, TMC derivatives, amidated chitosan and amidated chitosan bearing imidazolium salts. The prepared chitosan derivatives were characterized by FT-IR and H NMR. The tests evaluated the biological antioxidant, antibacterial, and cytotoxic activities of chitosan derivatives.

Preparation, Anticoagulant and Antioxidant Properties of Glucosamine-Heparin Salt.

Excessive inorganic ions in vivo may lead to electrolyte disorders and induce damage to the human body. Therefore, preparation of enhanced bioactivity compounds, composed of activated organic cations and organic anions, is of great interest among researchers. In this work, glucosamine-heparin salt (GHS) was primarily synthesized with positively charged glucosamine hydrochloride (GAH) and negatively charged heparin sodium (Heps) by ion exchange method.

Synthesis, Characterization, and the Antioxidant Activity of Phenolic Acid Chitooligosaccharide Derivatives.

A series of phenolic acid chitooligosaccharide (COS) derivatives synthesized by two mild and green methods were illuminated in this paper. Seven phenolic acids were selected to combine two kinds of COS derivatives: the phenolic acid chitooligosaccharide salt derivatives and the phenolic-acid-acylated chitooligosaccharide derivatives. The structures of the derivatives were characterized by FT-IR and H NMR spectra.

Preparation of Doxorubicin-Loaded Carboxymethyl-β-Cyclodextrin/Chitosan Nanoparticles with Antioxidant, Antitumor Activities and pH-Sensitive Release.

In this study, chitosan nanoparticles (HF-CD NPs) were synthesized by an ionic gelation method using negatively charged carboxymethyl-β-cyclodextrin and positively charged 2-hydroxypropyltrimethyl ammonium chloride chitosan bearing folic acid. The surface morphology of HF-CD NPs was spherical or oval, and they possessed relatively small particle size (192 ± 8 nm) and positive zeta potential (+20 ± 2 mV). Meanwhile, doxorubicin (Dox) was selected as model drug to investigate the prepared nanoparticles' potential to serve as a drug delivery carrier.

Enhanced antifungal and antioxidant activities of new chitosan derivatives modified with Schiff base bearing benzenoid/heterocyclic moieties.

In this work, chitosan derivatives modified with Schiff base bearing benzenoid/heterocyclic moieties were successfully prepared via amidation reaction. Specific structural characterization was implemented using FTIR and H NMR, and the DS of chitosan derivatives were quantitatively calculated by ratio of hydrogen proton integral. Meanwhile, the antifungal activity against two common plant pathogenic fungi (Fusarium oxysporum f.

Antimicrobial and Antioxidant Activities of -2-Hydroxypropyltrimethyl Ammonium Chitosan Derivatives Bearing Amino Acid Schiff Bases.

-2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC), a cationic quaternary ammonium salt polymer exhibiting good solubility in water, is widely used because of its low toxicity and good biocompatibility. Herein, through ion exchange reaction, we prepared -2-hydroxypropyltrimethyl ammonium chitosan derivatives bearing amino acid Schiff bases with good biological activities. The accuracy of the structures was verified by FT-IR and H NMR.

The influence of bioactive glyoxylate bearing Schiff base on antifungal and antioxidant activities to chitosan quaternary ammonium salts.

In this study, to investigate the influence of glyoxylate bearing Schiff base on bioactivity to chitosan quaternary ammonium salts, different chitosan derivatives were synthesized by ion exchange of glyoxylate bearing Schiff base with chitosan quaternary ammonium salts (TMCI and HACC). For this purpose, glyoxylate was prepared by Schiff base reaction of glyoxylic acid and amino heterocycles and it was further ionization to substitute iodide ions and chloride ions. After structural characterization by FTIR and H NMR, the antifungal and antioxidant activities were measured.

Facile synthesis, characterization, antioxidant activity, and antibacterial activity of carboxymethyl inulin salt derivatives.

A series of novel carboxymethyl inulin derivatives bearing thiosemicarbazide salts, aminoguanidine salts, and aniline salts were prepared via a facile method and employed to evaluate in vitro antioxidant activity and antibacterial activity. Their structures were characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The characterization results confirmed the successful synthesis of carboxymethyl inulin salt derivatives.

New synthetic adriamycin-incorporated chitosan nanoparticles with enhanced antioxidant, antitumor activities and pH-sensitive drug release.

In this paper, adriamycin-incorporated chitosan nanoparticles were synthesized by ionic gelation using negatively charged carboxymethyl chitosan and positively charged 2-hydroxypropyltrimethyl ammonium chloride chitosan. The method was efficient to obtain nanoparticles with low polydispersity index and small hydrodynamic diameter. And high zeta potential value indicated that nanoparticles had good stability.

Synthesis, Characterization, and Evaluation of Nanoparticles Loading Adriamycin Based on 2-Hydroxypropyltrimethyl Ammonium Chloride Chitosan Grafting Folic Acid.

Chitosan nanoparticles have been considered as potential candidates for drug loading/release in drug delivery systems. In this paper, nanoparticles (HACAFNP) loading adriamycin based on 2-hydroxypropyltrimethyl ammonium chloride chitosan grafting folic acid (HACF) were synthesized. The surface morphology of the novel nanoparticles was spherical or oval, and the nanoparticles exhibited a relatively small hydrodynamic diameter (85.

Novel 2-Hydroxypropyltrimethyl Ammonium Chitosan Derivatives: Synthesis, Characterization, Moisture Absorption and Retention Properties.

Recent years have seen a steady increase in interest and demand for the use of humectants based on biodegradable natural polymers in many fields. The aim of this paper is to investigate the moisture absorption and retention properties of 2-hydroxypropyltrimethyl ammonium chitosan derivatives which were modified by anionic compounds via ion exchange. FTIR, H NMR, and C NMR spectroscopy were used to demonstrate the specific structures of chitosan derivatives.

Determination of chitosan content with Schiff base method and HPLC.

Tremendous awareness of determination of chitosan content accurately is increasing, due to it has great significance to the quality control of chitosan. In this article, two kinds of chitosan-Schiff base derivatives (BCSB and PCSB) were synthesized by the different average degrees of deacetylation (DD) of chitosan with benzaldehyde or propanal, respectively. The total mass of Schiff base derivative product was dried and obtained without washing and loss.

Modification of carboxymethyl inulin with heterocyclic compounds: Synthesis, characterization, antioxidant and antifungal activities.

A series of novel inulin derivatives were designed and synthesized by the introduction of amino heterocyclic moieties onto carboxymethyl inulin with the aid of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide. The target products were prepared via three - step chemical synthesis, and structures were identified by FTIR and H NMR spectroscopy. Antioxidant activities of inulin derivatives including DPPH - radical scavenging assay, superoxide - radical scavenging assay, hydroxyl - radical scavenging assay, and reducing power were estimated.

Modification of Hydroxypropyltrimethyl Ammonium Chitosan with Organic Acid: Synthesis, Characterization, and Antioxidant Activity.

A novel and green method for the preparation of chitosan derivatives bearing organic acids was reported in this paper. In order to improve the antioxidant activity of chitosan, eight different hydroxypropyltrimethyl ammonium chitosan derivatives were successfully designed and synthesized via introducing of organic acids onto chitosan by mild and non-toxic ion exchange. The data of Fourier Transform Infrared (FTIR), C Nuclear Magnetic Resonance (NMR), H NMR, and elemental analysis for chitosan derivatives indicated the successful conjugation of organic acid salt with hydroxypropyltrimethyl ammonium chloride chitosan (HACC).