Fungicidal nanoparticles of low toxicity from cationic lipid and polyelectrolytes

L.D. Melo, A.M. Carmona-Ribeiro
Universidade de São Paulo, BR

Keywords: dioctadecyldimethylammonium bromide, bilayer fragments, carboxymethylcellulose, polydiallyldimethylammonium chloride, particles from self-assembly, activity against Candida albicans

Summary:

The assembly of the cationic lipid dioctadecyldimethylammonium bromide (DODAB) and polyelectrolytes such as carboxymethylcellulose (CMC) and polydiallyldimethylammonium chloride (PDDA) produced bactericidal nanoparticles in complete absence of antibiotics. In this work, these nanoparticles are evaluated regarding their activity against Candida albicans and toxicity against mammalian red blood cells. At 0.1 and 0.5 mM DODAB, 0.1 and 0.5 mg/mL CMC, 0.1 and 0.5 mg/mL PDDA, small (SP) and large stable particles (LP), respectively, are obtained. SP and LP exhibit 107 and 240 nm mean diameter, respectively, and 40 and 46 mV of zeta-potential, respectively. At 0.5 µg/mL PDDA (alone or on particles), fungus viability from plating is zero. Under similar experimental conditions, DODAB alone or DODAB/CMC assemblies do not kill the fungus. Therefore, the active layer in the DODAB/CMC/PDDA assembly is the outermost PDDA layer. Particle size barely affects activity: very similar PDDA doses are required for SP or LP. Each element from the assembly and the assembly itself display low hemolytic activity (0 -5 % hemolysis) at concentrations well above the minimal fungicidal concentration. The bactericidal, fungicidal and nontoxic particles may find interesting applications in antimicrobial chemotherapy.