Chitosan functionalization with a series of sulfur-containing α-amino acids for the development of drug-binding abilities

Multifunctional nanoparticles based on marine polysaccharides for apremilast delivery to inflammatory macrophages: Preparation, targeting ability, and uptake mechanism

Hydrophobic drug encapsulation inside targeted nanoparticles can enhance accumulation in inflamed sites, limit toxicity to healthy tissue, and improve pharmacokinetics compared to free drug dosing. This study reports a functionalized marine polysaccharide nanoparticle with a controlled release, targeting abilities, and in-situ imaging properties. Carbon dots functionalized Enteromorpha polysaccharide/Mannose/Methionine functionalized Chitosan (CDs.EP/Man/Meth.Cs) NPs could deliver apremilast to inflammatory macrophages and Caco-2 intestinal cells as an in vitro model for application in oral drug delivery to cure IBD. The nanoparticles were simply a polyelectrolyte complex between cationic functionalized chitosan and anionic polysaccharide of Enteromorpha prolifera. Functionalized polysaccharides and the prepared NPs were well characterized. The functionalized nanoparticles could overcome the limitation of poor drug bioavailability and showed a high loading capacity of (45 %) with a controlled release of about (74.5 %). Confocal laser scanning imaging showed higher cellular uptake of the modified nanoparticles than that of the unmodified nanoparticles in LPS-activated RAW 264.7 macrophages and Caco-2 cells. The effect of functionalization on the cellular uptake targetability was assessed using spectrofluorometric measurements after mannose competition. Anti-inflammatory activity of apremilast-loaded NPs is more elevated than the free drug. These results suggest the feasibility of using functionalized EP/Cs nanoparticles in IBD oral drug delivery.

Adsorption dynamics of phenol by crab shell chitosan

The performance of crab shell chitosan (600 µm) as prospective adsorbent for phenol removal was studied in dynamics mode. The chitosan adsorbent had specific surface area of 191 m2/g and showed the surface characteristics linked to amine/amide groups. The effects of operating conditions on phenol adsorption at different concentrations (100 and 200 mg/L), flow rates (2.17 and 2.90 mL/min) and bed heights (1.75 and 3.5 cm) were evaluated. Results showed that the maximum phenol adsorption capacity by the crab shell chitosan was recorded at 190 mg/g. Thomas, Yoon–Nelson and Adam–Bohart models displayed good correlation with experimental data, hence best described the dynamics breakthrough of phenol removal. External and internal diffusion were the rate controlling mechanism, while the entire system was predominated by a simultaneous steady state process of intraparticle diffusion and ionic interactions. The crab shell chitosan shows a promising potential as adsorbent for wastewater treatment.

Methylene Blue Adsorption onto Neem Leave/Chitosan Aggregates: Isotherm, Kinetics and Thermodynamics Studies

The work was aimed at evaluating the adsorptive properties of neem leave/chitosan aggregates for methylene blue removal. The adsorbent was screened to form coarse (CCANL, 600 µm), medium (MCANL, 300 µm) and fine (FCANL, 150 µm) neem leave/chitosan particles. The samples were characterized for pH, water binding capacity (WBC), surface chemistry by Fourier transform infrared spectroscopy, surface morphology by scanning electron microscope and textural properties by Brunauer-Emmett-Teller method. CCANL, MCANL and FCANL possessed specific surface area of 255, 258 and 242 m2/g, respectively. The effects of initial concentration, adsorbent dosage, contact time, pH and temperature were studied. CCANL, MCANL and FCANL demonstrated adsorption capacity of 102, 92.5 and 105 mg/g, respectively, in which ionic interaction and mesopore filling were the possible adsorption mechanisms. The equilibrium data were well fitted by Redlich-Peterson model, suggesting a monolayer adsorption onto a heterogeneous surface of adsorbent. The kinetics data were best described by pseudo-second-order and intraparticle diffusion models, for which the film diffusion, intraparticle diffusion and surface adsorption could co-exist as the controlling steps in adsorption. Adsorption of methylene blue onto chitosan composites was spontaneous, endothermic and demonstrated increased randomness at solid-solution interface.