Colloid Stability of Lipid/Polyelectrolyte Decorated Latex

Abstract

The colloid stability of supramolecular assemblies composed of the synthetic cationic lipid dioctadecyldimethylammonium bromide (DODAB) on carboxymethyl cellulose (CMC) supported on polystyrene amidine (PSA) microspheres was evaluated via turbidimetry kinetics, dynamic light scattering for particle sizing, zeta-potential analysis, and determination of DODAB adsorption on CMC-covered particles. At 0.1 g L(-1) CMC and 2 x 10(11) PSA particles/mL, CMC did not induce significant particle flocculation, and a vast majority of CMC-covered single particles were present in the dispersion so that this was the condition chosen for determining DODAB concentration (C) effects on particle size and zeta potentials. At 0.35 mM DODAB, charge neutralization, maximal size, and visible precipitation indicated extensive flocculation and minimal colloid stability for the DODAB/CMC/PSA assembly. At 0.1 g L(-1) CMC, isotherms of high affinity for DODAB adsorption on CMC-covered particles presented a plateau at a limiting adsorption of 700 x 10(17) DODAB molecules adsorbed per square meter PSA which was well above bilayer deposition on a smooth particle surface. The polyelectrolyte layer on hydrophobic particles was swelled and fluffy (ca. 11-nm hydrodynamic thickness), and maximal adsorption of DODAB lipid onto this layer produced a compressed composite cationic film with 20 mV of zeta potential and about 10-nm mean thickness. The assembly of cationic lipid/CMC layer/polymeric particle was stable only well above charge neutralization of the polyelectrolyte by the cationic lipid, at relatively large lipid concentrations (at and above 1 mM DODAB) with charge neutralization leading to extensive particle aggregation.

Cationic nanoparticles for delivery of amphotericin B: preparation, characterization and activity in vitro

“…In the presence of CMC, there are two regions of colloid stability for cationic or anionic assemblies characterized by small sizes: regions I and III, and one region of instability: region II, characterized by aggregation and large sizes (Figure 1 ). Charged particles covered by oppositely charged polyelectrolytes exhibited similar profiles for the colloid stability as a function of polyelectrolyte concentration [ 36 , 37 ].…”

The Versatile Dioctadecyldimethylammonium Bromide

“…DODAB remarkable interactive capability with opposite charges of silica particles [20][21][22][23], silicon wafers [24], polymeric particles [25][26][27][28][29][30][31]; polymer films [32][33][34], drugs [35][36][37][38][39][40][41][42][43][44][45], nucleic acids [31,46], oligonucleotides [47][48][49], proteins [30,[50][51][52][53][54], peptides [9,[55][56][57], polyelectrolytes [8,9,36,58,59] and many other important surfaces, biological cells, molecules and nanostructures [60][61][62]…”

“…Aiming at the production of nanoparticles (NPs) for drug delivery, DODAB has been very useful to harmonize oppositely charged polysaccharides such as carboxymethylcellulose [58] or hyaluronic acid [86] with hydrophobic drugs such as amphotericin B [36], indomethacin [45], and tocoferol (vitamin E) [86]. Carboxymethylcellulose/DODAB/indomethacin NPs were prepared by direct injection of DODAB/indomethacin ethanol solution into a carboxymethylcellulose water solution [45].…”

Biomimetic Systems in Nanomedicine

“…188 BF preparation, characterization and biomedical applications have been often reviewed in the literature over the last 5 years. [189][190][191][192][193][194] Applications for cationic BF include the incorporation and delivery of drugs, [195][196][197] incorporation of antigens, 95 oligonucleotides, 198,199 peptides, 200 polysaccharides, [201][202] coverage of drug particles, 196,203 and activity against pathogenic microorganisms. [174][175][176][177][178]204 Charged BF can be stabilized in aqueous solution as nanostructures both electrostatically by using a dispersion medium prepared at a low ionic strength (usually at 1 mM NaCl) and/or sterically by interaction with hydrophilic polymers 100,205 or PEGylated lipids.…”