Kinetic-dependent killing of oral pathogens with nitric oxide

Nitric oxide (no)-releasing silica nanoparticles were synthesized via the co-condensation of tetramethyl orthosilicate with aminosilanes and subsequent conversion of secondary amines to n-diazeniumdiolate no donors. a series of ∼150 nm no-releasing particles with different no totals and release kinetics (i.e.,half-lives) were achieved by altering both the identity and mol% composition of the aminosilane precursors. independent of identical 2 h no-release totals,enhanced antibacterial action was observed against the periodontopathogens aggregatibacter actinomycetemcomitans and porphyromonas gingivalis with extended no-release kinetics at ph 7.4. negligible bactericidal effect was observed against cariogenic streptococcus mutans at ph 7.4,even when using no-releasing silica particles with greater no-release totals. however,antibacterial activity was observed against s. mutans at lower ph (6.4). this result was attributed to more rapid proton-initiated decomposition of the n-diazeniumdiolate no donors and greater no-release payloads. the data suggest a differential sensitivity to no between cariogenic and periodontopathogenic bacteria with implications for the future development of no-releasing oral care therapeutics. © international & american associations for dental research.