Synthesis, characterization, and properties of cashew gum graft poly(acrylamide)/magnetite nanocomposites

Hybrid nanocomposite of kappa-carrageenan and magnetite as adsorbent material for water purification

A novel polysaccharide based hydrogel; kappa-carrageenan grafted with N-hydroxyethylacrylamide (κC-g-PHEAA) was synthesized via microwave assisted free radical polymerization process. A hybrid nanocomposite has also been made by incorporation of Fe₃O₄ nanoparticles into the κC-g-PHEAA network. The materials were characterized by FTIR, TGA, XRD, SEM, BET and VSM techniques. The nanocomposite exhibited super-paramagnetic behavior. The κC-g-PHEAA and κC-g-PHEAA/Fe₃O₄ presented significant adsorption capacity towards cationic dyes, methylene blue (MB) and rhodamine 6G (R6G); and metal ions, Cu(II) and Hg(II) from aqueous solution. The magnetite nanoparticles enhance the adsorption characteristics of the hydrogel and enables easy separation of the adsorbent with an external magnetic field. Adsorption process is observed to follow both Langmuir and Freundlich isotherm models for R6G and Freundlich isotherm model for MB, Cu(II) and Hg(II). The adsorption was found to be a pseudo first order process for MB and pseudo second order process for R6G, Cu(II) and Hg(II). Thermodynamic studies have shown the adsorption of dyes and metal ions to be spontaneous and endothermic in nature. The desorption studies revealed the efficient recovery of adsorbate species. The study indicates that the synthesized adsorbents have potential applications for the removal of dyes and metal ions from wastewater.

Self-assembling cashew gum-graft-polylactide copolymer nanoparticles as a potential amphotericin B delivery matrix

Amphotericin B is an antibiotic used in the treatment of fungal disease and leishmania; however, it exhibits side effects to patients, hindering its wider application. Therefore, nanocarriers have been investigated as delivery systems for amphotericin B (AMB) in order to decrease its toxicity, besides increase bioavailability and solubility. Amphiphilic copolymers are interesting materials to encapsulate hydrophobic drugs such as AMB, hence copolymers of cashew gum (CG) and l-lactide (LA) were synthesized using two different CG:LA molar ratios (1:1 and 1:10). Data obtained revealed that copolymer nanoparticles present similar figures for particle sizes and zeta potentials; however, particle size of encapsulated AMB increases if compared to unloaded nanoparticles. The 1:10 nanoparticle sample has better stability although higher polydispersity index (PDI) if compared to 1:1 sample. High amphotericin (AMB) encapsulation efficiencies and low hemolysis were obtained. AMB loaded copolymers show lower aggregation pattern than commercial AMB solution. AMB loaded nanoparticles show antifungal activities against four C. albicans strains. It can be inferred that cashew gum/polylactide copolymers have potential as nanocarrier systems for AMB.

Potential anticancer activity of protocatechuic acid loaded in montmorillonite/Fe3O4 nanocomposites stabilized by seaweed Kappaphycus alvarezii

Superparamagnetic magnetite nanocomposites (Fe₃O₄-NCs) were successfully synthesized, which comprised of montmorillonite (MMT) as matrix support, Kappaphycus alvarezii (SW) as bio-stabilizer and Fe₃O₄ as filler in the composites to form MMT/SW/Fe₃O₄-NCs. Nanocomposite with 0.5 g Fe₃O₄ (MMT/SW/0.5Fe₃O₄) was selected for anticancer activity study because it revealed high crystallinity, particle size of 7.2 ± 1.7 nm with majority of spherical shape, and M_s = 5.85 emu/g with negligible coercivity. Drug loading and release studies were carried out using protocatechuic acid (PCA) as the model for anticancer drug, which showed 19% and 87% of PCA release in pH 7.4 and 4.8, respectively. Monolayer anticancer assay showed that PCA-loaded MMT/SW/Fe₃O₄ (MMT/SW/Fe₃O₄-PCA) had selectivity towards HCT116 (colorectal cancer cell line). Although MMT/SW/Fe₃O₄-PCA (0.64 mg/mL) showed higher IC₅₀ than PCA (0.148 mg/mL) and MMT/SW/Fe₃O₄ (0.306 mg/mL, MMT/SW/Fe₃O₄-PCA showed more effective killing towards tumour spheroid model generated from HCT116. The IC₅₀ for MMT/SW/Fe₃O₄-PCA, MMT/SW/Fe₃O₄ and PCA were 0.132, 0.23 and 0.55 mg/mL, respectively. This suggests the improved penetration efficiency and drug release of MMT/SW/Fe₃O₄-PCA towards HCT116 spheroids. Moreover, concentration that lower than 2 mg/mL MMT/SW/Fe₃O₄-PCA did not result any hemolysis in human blood, which suggests them to be ideal for intravenous injection. This study highlights the potential of MMT/SW/Fe₃O₄-NCs as drug delivery agent.