Lilian Barbassa

Background Cationic bilayers based on the inexpensive synthetic lipid dioctadecyldimethylammonium bromide (DODAB) have been useful as carriers for drug delivery, immunoadjuvants for vaccines and active antimicrobial agents. Methods Rifampicin (RIF) or isoniazid (ISO) interacted with DODAB bilayer fragments (BF) or large vesicles (LV). Dispersions were evaluated by dynamic light-scattering for zeta-average diameter (Dz) and zeta-potential (ζ) analysis; dialysis for determination of drug entrapment efficiency; plating and CFU counting for determination of cell viability of Mycobacterium smegmatis or tuberculosis, minimal bactericidal concentration (MBC) and synergism index for DODAB/drug combinations. Results DODAB alone killed micobacteria over a range of micromolar concentrations. RIF aggregates in water solution were solubilised by DODAB BF. RIF was incorporated in DODAB bilayers at high percentiles in contrast to the leaky behavior of ISO. Combination DODAB/RIF yielded MBCs of 2/2...

A vast territory for research is open from mimicking the behaviour of microorganisms to defend themselves from competitors. Antibiotics secreted by bacteria or fungi can be copied to yield efficient molecules which are active against infectious diseases. On the other hand, nanotechnology provides novel techniques to probe and manipulate single atoms and molecules. Nanoparticles are finding a large variety of biomedical and pharmaceutical applications, since their size scale can be similar to that of biological molecules (e.g. proteins, DNA) and structures (e.g. viruses and bacteria). They are currently being used in imaging (El-Sayed et al., 2005), biosensing (Medintz et al.,2005), biomolecules immobilization (Carmona-Ribeiro, 2010a), gene and drug delivery (Carmona-Ribeiro, 2003; CarmonaRibeiro, 2010b) and vaccines (O ́Hagan et al., 2000; Lincopan & Carmona-Ribeiro, 2009; Lincopan et al., 2009). They can also incorporate antimicrobial agents (antibiotics, metals, peptides, surfacta...