Funcionalização de carbon dots com peptídeo antimicrobiano ecPis-4s

The methodology of carbon dots (CDs) preparation was performed by dehydration and oxidation reactions of cotton cellulose. The surface modification reaction of the CDs was carried out based on the concentration of superficial oxygenated functional groups. 50 mg of carbon dots were mixed with EDAC at 45 ºC under constant agitation. After 30 minutes of reaction, was added OxymaPure® and then a solution of the peptide. The materials obtained were characterized through different techniques, including Fourier Transform Infrared Spectroscopy (FTIR) (Figure 1) and zeta potential. After the functionalization with the peptide, the zeta potential of the CD nanoparticles changed from -50.5 mV to -23.4 mV, suggesting the consumption of some negatively charged functional groups, such as carboxy, at a pH below 6. The results of the antimicrobial activity, in vitro, showed that the functionalized nanoparticles are capable of inhibiting bacterial growth similary to ecPis-4s for Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). This outcome is directly related to the α-helix conformation of the peptide covalently attached to the surface of the CDs, as shown by the results obtained with circular dichroism in a membrane mimetic medium (Figure 2).