Strategy with tt-farnesol, myricetin and compound 1771 associated with nanoparticle carries is effective to preventing cariogenic biofilms formed by Streptococcus mutans and Candida albicans in vitro

The development of effective therapies for the control of oral biofilm is a challenge. Topical agents used to treat and/or prevent oral diseases caused by biofilms, generally, are not maintained in the mouth for a sufficient time to they exercise their maximum therapeutic potential. Thus, nanoparticle carries (NPC) have been developed to adhere on hydroxyapatite, pellicle, and exopolysaccharides. NPCs has pH sensitive elements for releasing drugs controlled at acidic niches of pathogenic biofilms. The tt-farnesol and myricetin can be successfully carried and released by NPCs, decreasing biomass of Streptococcus mutans biofilm. Compound 1771 is a new drug for controlling the synthesis of lipoteichoic acids - cell wall protein from Gram-positive bacteria - responsible for microbial co-aggregation. The biofilm of S. mutans and Candida albicans is extremely pathogenic, leading to the development of severe carious lesions in a short period in vivo. Therefore, the objective were investigate whether the compound 1771 can be carried by NPC and also the treatment containing the association of the three drugs (NPC-farnesol-myricetin1771) can prevent mono-species biofilm formed by S. mutans with surface treated since the beginning of formation (prevention regimen) and multi-species formed by S. mutans and C. albicans under prevention regimen and control regimen (the biofilm was treated after stablished on the surface) in vitro. Thus, it was necessary to synthesize a nanoparticle and check the interaction with compound 1771 and characterize it, later testing the solutions against cariogenic biofilms. The tests for NPC-1771 characterization included size, zeta potential, absorbance, fluorescence, gel permeation chromatography and nuclear magnetic resonance. The polymer created was formed by two blocks, block 1 (corona) being responsible for adhering to exopolysaccharides and pellicle for being cationic nanoparticle and carrying the drugs: myricetin and compound 1771; and block 2 (core) is responsible for carrying insoluble drugs such as tt-farnesol, in addition to being pH sensitive, releasing them mainly as the pH drops. Absorbance and fluorescence tests confirmed the strong interaction between NPC and compound 1771. The other tests characterized the NPC's zeta-potential and size from +23 mV to 32 mV and from 48.3 to 75 d.nm pre/post drug association, respectively. The microbiological tests were made using minimum antimicrobial concentration using planktonic cultures. Two treatment regimens were prepared using biofilms formed on hydroxyapatite discs with pellicle. The pH of the culture medium, biomass of biofilms and population was monitored. Confocal and scanning electron microscopes were performed to characterize the three-dimensional structure. Lower concentrations of the drugs carried inhibited the planktonic bacterial growth but did not inhibit the fungus growth and the NPC free did not affect both microorganisms. The association of the drugs carried prevents the formation of biofilms by inhibiting the pH drop, microbial population and the production of extracellular matrix, consequently, biomass. The best efficacy occurred in the treatments NPC-farnesol-1771 and NPC-farnesol-myricetin-1771 in the prevention regimen. No treatments control biofilm formation in the control regimen. Therefore, the association of drugs, especially tt-farnesol and compound 1771 associated to NPC prevented the biofilm formation on hydroxyapatite surface. (AU)