Activity-Structure Study on the Peptide Fraction of AG2: a Potent In Vitro Transfection Agent.

Gemini-based amphiphiles are candidates for biomedical applications. In fact, most of the gemini compounds described in the literature have been prepared to be used as new synthetic vectors in gene transfection. Our group carried out an activity-structure study starting from the structure of the gemini [AG2-C18/]2, which is an effective in vitro transfection reagent. We synthesized a series of novel amphiphilic amino acid derivatives of low molecular weight, named AGn-Cm (N), in which the same apolar region (m) of oleic or palmitic acid was maintained and the peptide region was modified by amino acid insertions, deletions, and substitutions. We also determined the transfection efficiency, critical micelle concentration, particle size, and ζ-potential for these derivatives. Amphiphiles AG10-C16 and AG10-C18 were more active at a lower N/P ratio than AG2-C18. These amphiphiles showed no activity when lysine was replaced by ornithine, and the activity of all derivatives increased when there were more ornithine residues and a W/O = 1 ratio in the peptide region. It can be said that for AG10-C16, these two structural requirements on the amino acid portion predominated over the type of aliphatic chain used.

A controlled antibiotic release system to prevent orthopedic-implant associated infections: An in vitro study.

A new device for local delivery of antibiotics is presented, with potential use as a drug-eluting fixation pin for orthopedic applications. The implant consists of a stainless steel hollow tubular reservoir packed with the desired antibiotic. Release takes place through several orifices previously drilled in the reservoir wall, a process that does not compromise the mechanical properties required for the implant. Depending on the antibiotic chosen and the number of orifices, the release profile can be tailored from a rapid release of the load (ca. 20h) to a combination of rapid initial release and slower, sustained release for a longer period of time (ca. 200h). An excellent bactericidal action is obtained, with 4-log reductions achieved in as little as 2h, and total bacterial eradication in 8h using 6-pinholed implants filled with cefazolin.