Formation and structure of chitosan–poly(sodium methacrylate) complex nanoparticles

A Comparison of Interpolyelectrolyte Complexes (IPECs) Made from Anionic Block Copolymer Micelles and PDADMAC or q-Chitosan as Polycation

Block copolymers synthesized via Atom Transfer Radical Polymerization from alkyl acrylate and t-butyl acrylate and the subsequent hydrolysis of the t-butyl acrylate to acrylic acid were systematically varied with respect to their hydrophobic part by the variation in the alkyl chain length and the degree of polymerisation in this block. Depending on the architecture of the hydrophobic part, they had a more or less pronounced tendency to form copolymer micelles in an aqueous solution. They were employed for the preparation of IPECs by mixing the copolymer aggregates with the polycations polydiallyldimethylammonium chloride (PDADMAC) or q-chit. The IPEC structure as a function of the composition was investigated by Static Light and Small Angle Neutron Scattering. For weakly-associated block copolymers (short alkyl chain), complexation with polycation led to the formation of globular complexes, while already existing micelles (long alkyl chain) grew further in mass. In general, aggregates became larger upon the addition of further polycation, but this growth was much more pronounced for PDADMAC compared to q-chit, thereby leading to the formation of clusters of aggregates. Accordingly, the structure of such IPECs with a hydrophobic block depended largely on the type of complexing polyelectrolyte, which allowed for controlling the structural organisation via the molecular architecture of the two oppositely charged polyelectrolytes.

Synthesis of biodegradable antimicrobial pH-sensitive silver nanocomposites reliant on chitosan and carrageenan derivatives for 5-fluorouracil drug delivery toward HCT116 cancer cells

The current research relies on a one-pot green biosynthesis of silver nanoparticles (SNPs) with various ratios of silver (Ag) in the existence of N, N, N-trimethyl chitosan chloride (TMC) and carboxymethyl kappa-carrageenan (CMKC), to investigate the effectiveness of the synthesized silver nanocomposites (SNCs) as pH sensitive biodegradable carrier for orally intestinal delivery of 5-fluorouracil (5-FU) drug. FTIR, XRD, TEM and FE-SEM/EDX methods were utilized to demonstrate the structure of the prepared polyelectrolyte complex PEC (TMC/CMKC) and SNCs (TMC/CMKC/Ag). The results showed that the 5-FU encapsulation effectiveness inside all of the prepared SNCs samples was improved by increasing the concentration of Ag, reaching 92.16 ± 0.57 % with 3 % Ag. In vitro release behavior of 5-FU loaded SNC 3 % (TMC/CMKC/Ag 3 %), displayed slow and sustained release reaching 96.3 ± 0.81 % up to 24 h into pH 7.4 medium. The successful release of 5-FU from the loaded SNC 3 % was confirmed through occurrence of strong cytotoxicity, with an IC₅₀ value of 31.15 μg/ml, and high % of apoptotic cells (30.66 %) within the treated HCT116 cells. Besides, SNC 3 % showed good biodegradability and antimicrobial properties against different bacterial strains. Overall, SNC 3 % can be suggested as an effective system for both controlled drug delivery and antibacterial action.