Dual Cross-Linked Chitosan-Based Films with pH-Sensitive Coloration and Drug Release Kinetics for Smart Wound Dressings.

In this study, we developed dual-cross-linked hydrogel films based on carboxyethyl chitosan (CECS) and sodium alginate (SA), utilizing dialdehyde β-cyclodextrin (DA-βCD) and gluconic acid δ-lactone (GDL) as cross-linkers. Designed as smart wound dressings, the films exhibit pH sensitivity due to the incorporation of carboxyethylated phenol red-grafted chitosan (CS-PR-AA), which allows them to change color from orange to purple in response to pH variations. FT-IR and TGA analyses confirmed the formation of imine bonds and polyelectrolyte complexes, indicating successful cross-linking.

Advanced chitosan hybrid dye labels for dynamic monitoring of shrimp and milk freshness.

This study presents the development of intelligent screen-printed labels for real-time food freshness monitoring. Using chitosan grafted with rosolic acid (RA) and immobilized on montmorillonite (MMT) through cationic exchange, a hybrid dye was synthesized and applied in screen-printing inks. The hybrid structure was characterized by XRD, TGA, and UV-vis, confirming improved thermal stability and maintained halochromic properties.

Development of a pH-responsive intelligent label using low molecular weight chitosan grafted with phenol red for food packaging applications.

In this study, we successfully developed a screen-printed pH-responsive intelligent label using low molecular weight chitosan grafted with phenol red (LCPR) as a colorant for screen printing ink. The LCPR was synthesized via a Mannich reaction, and its successful grafting was confirmed through FT-IR, UV-vis, and NMR spectroscopy. The LCPR exhibited lower crystallinity and thermal stability compared to low molecular weight chitosan (LC) and demonstrated zwitterionic behavior.

Facile construction of magnetic solid-phase extraction of polyaniline blend poly(amidoamine) dendrimers modified graphene oxide quantum dots for efficient adsorption of polycyclic aromatic hydrocarbons in environmental water.

An efficient magneto-adsorbent composed of polyaniline blend poly(amidoamine) dendrimers modified graphene oxide quantum dots and magnetic FeO particles (FeO@PANI-PSS/PAMAM-QGO) for magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water was synthesized. FeO@PANI-PSS/PAMAM-QGO exhibited exceptional adsorption property for most PAHs analytes. The nanocomposite sorbent demonstrated a ferromagnetic behavior of 17.

A Ratiometric Fluorescence Amplification Using Copper Nanoclusters with -Phenylenediamine Sensor for Determination of Mercury (II) in Natural Water.

A simple and rapid method for determining mercury (II) has been developed using L-cysteine-capped copper nanocluster (CuNCs) with -phenylenediamine (OPD) as the sensor. The characteristic fluorescence peak of the synthesized CuNCs was observed at 460 nm. The fluorescence properties of CuNCs were strongly influenced by the addition of mercury (II).

New Chitosan-Grafted Thymol Coated on Gold Nanoparticles for Control of Cariogenic Bacteria in the Oral Cavity.

Chitosan-grafted thymol (CST) coated on gold nanoparticles has been synthesized and characterized for the design of antimicrobial materials. CST was synthesized via adapting the Mannich reaction, and it acted as the capping agent for the synthesis of gold nanoparticles (AuNPs). The grafting of thymol onto the side chain of chitosan has provided a degree of substitution value (%DS) of 10.

Synthesis of chitosan-based polymeric dyes as colorimetric pH-sensing materials: Potential for food and biomedical applications.

pH-sensitive polymeric dyes were fabricated by grafting phenol red (PR) and rosolic acid (RA) onto chitosan (CS) by a facile method. Successful grafting was confirmed by H NMR, FT-IR, UV-vis, XRD, and elemental analysis. The polymeric dyes exhibited no cell toxicity.

Cationic starch intercalated montmorillonite nanocomposites as natural based adsorbent for dye removal.

Cationic starch intercalated montmorillonite (Mt-CST) adsorbent was developed for the removal of basic dyes, namely, Basic Blue (BB66) and Basic Yellow (BY1) from aqueous solution. Cationic starches (CST) containing ammonium groups with the degree of substitution of 0.16 (CST1) and 0.

Silver loaded hydroxyethylacryl chitosan/sodium alginate hydrogel films for controlled drug release wound dressings.

Wound dressings composed of hydroxyethylacryl chitosan (HC) and sodium alginate (SA) were developed with antibacterial activity by loading Ag particles. The formation of Ag particle in the HC/SA films was achieved by an immersion method through in situ chemical reduction of AgNO solution and confirmed by FTIR, SEM-EDS, XRD and XRF techniques. The effect of Ag loading in the Ca-crosslinked HC/SA films with different crosslinking density was studied on swelling behavior, mechanical properties, cytotoxicity, antibacterial activity and drug release behavior.

Dual pH/thermal-dependent coloring polymeric dye through Mannich reaction of chitosan: Synthesis and characterization.

A novel polymeric dye was synthesized by one-pot Mannich reaction of chitosan (CS) and phenolphthalein (PHP). The grafting onto side chain of CS derivatives was confirmed by UV-vis, FT-IR, H NMR techniques. The degree of substitution (DS) calculated by H NMR and elemental analysis was revealed to increase with increasing mole ratio of formaldehyde and PHP.

In vitro drug release profiles of pH-sensitive hydroxyethylacryl chitosan/sodium alginate hydrogels using paracetamol as a soluble model drug.

The aim of this study is to investigate in vitro drug release profiles of pH-sensitive hydrogels composed of hydroxyethylacryl chitosan (HC) and sodium alginate (SA). The hydrogels were crosslinked by dipping method using different ionic crosslinkers (e.g.

Effect of ring-opening polymerization condition on the characteristic and mechanical properties of hydroxyapatite/poly(ethylene glutarate) biomaterials.

Preparation of hydroxyapatite/poly(ethylene glutarate) (HAp/PEG) composites was carried out by ring-opening polymerization (ROP) of cyclic oligo(ethylene glutarate) in porous HAp scaffolds using various reaction temperatures and times. The content of ROP-PEG interpenetrated into the porous HAp scaffold was about 13-18 wt % with the values of number average molecular weight (overline_M{n}) and weight average molecular weight (overline_M{W}) of 2120-3630 and 2760-5250 g/mol, respectively. The increase in polymerization time and temperature brought about increase in molecular weight of ROP-PEG, but decrease in its content.

Preparation and characterization of hydroxyapatite/poly(ethylene adipate) hybrid composites.

Hydroxyapatite/poly(ethylene adipate) (HAp/PEA) composites were prepared by in situ ring-opening polymerization of cyclic oligo(ethylene adipate) (C-OEA) within the porous HAp templates. HAp was firstly prepared by a co-precipitation method using calcium hydroxide and phosphoric acid and then shaped as a rectangular porous template. PEA precursor was synthesized by bulk polymerization of dimethyl adipate and ethylene glycol in the presence of tetraisopropyl orthotitanate.

Poly(ethylene terephthalate)/hydroxyapatite biomaterials: preparation, characterization, and in vitro bioactivity.

Poly(ethylene terephthalate)/hydroxyapatite (PET/HAp) composites were prepared by mixing HAp powder with a mixture solution of cyclic oligo(ethylene terephthalate) (C-OET) and dibutyl tinoxide catalyst in dichrolomethane, and then shaping the precomposites in cylindrical pellets. The C-OET in the precomposites was ring-opening polymerized (ROP) to PET under vacuum at 250 degrees C for 24 h. The PET/HAp composites were formulated with HAp to PET ratios of 60:40 (H6P4) and 50:50 (H5P5).

Preparation of hydroxyapatite/poly(methyl methacrylate) and calcium silicate/poly(methyl methacrylate) interpenetrating hybrid composites.

Hydroxyapatite/poly(methyl methacrylate) (HAp/PMMA) and calcium silicate/poly(methyl methacrylate) (CS/PMMA) composites were prepared by interpenetrating bulk polymerization of methyl methacrylate (MMA) monomer in porous structures of HAp and CS. The porous HAp and CS templates were prepared by mixing their calcined powders with poly(vinyl alcohol) (PVA) solution, shaping by uniaxial pressing and then firing at 1,100 degrees C for HAp and 900 degrees C for CS. The templates were soaked in the solution mixture of MMA monomer and 0.

Preparation and characterization of hydroxyapatite/poly(ethylene glutarate) biomaterials.

Hydroxyapatite/poly(ethylene glutarate) (HAp/PEG) biomaterial composites were prepared by ring-opening polymerization (ROP) of cyclic oligo(ethylene glutarate) (C-PEG) in porous HAp scaffolds. The HAp/C-PEG precomposites were prepared by immersing the porous HAp scaffolds in the mixture solution of C-PEG and dibutyl tinoxide catalyst overnight and polymerizing at 200 degrees C for 24, 48, and 72 h under vacuum. The successful ROP of C-PEG in the porous HAp scaffolds was corroborated by the signals of hydroxyl end-group of PEG shown in the (1)H NMR spectrum of the ROP-products extracted from the composites.