Controlling human pathogenic bacteria is a worldwide problem due to increasing bacterial resistance. This has prompted a number of studies investigating
peptides isolated from marine animals as a possible alternative for control of human pathogen
infections. Clavanins are
antimicrobial peptides isolated from the marine tunicate Styela clava, showing 23
amino acid residues in length, cationic properties, and also high bactericidal activity. In spite of clear benefits from the use of
peptides, currently 95% of
peptide properties have limited
pharmaceutical applicability, such as low solubility and short half-life in the circulatory system. Here, nanobiotechnology was used to encapsulate
clavanin A in order to develop nanoantibiotics against bacterial
sepsis. Clavanin was nanostructured using
EUDRAGIT(®) L 100-55 and RS 30 D
solution (3:1 w:w). Atomic force, scanning electron microscopy and dynamic light scattering showed nanoparticles ranging from 120 to 372 nm in diameter, with a zeta potential of -7.16 mV and a polydispersity index of 0.123. Encapsulation rate of 98% was assessed by reversed-phase chromatography. In vitro bioassays showed that the nanostructured clavanin was partially able to control development of Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Furthermore, nanostructures did not show hemolytic activity. In vivo
sepsis bioassays were performed using C57BL6 mice strain inoculated with a polymicrobial
suspension. Assays led to 100% survival rate under sub-lethal
sepsis assays and 40% under lethal
sepsis assays in the presence of nanoformulated
clavanin A until the seventh day of the experiment. Data here reported indicated that nanostructured
clavanin A form shows improved antimicrobial activity and has the potential to be used to treat
polymicrobial infections.