BAR-encapsulated nanoparticles for the inhibition and disruption of Porphyromonas gingivalis–Streptococcus gordonii biofilms

Abstract

BackgroundPorphyromonas gingivalis adherence to oral streptococci is a key point in the pathogenesis of periodontal diseases (Honda in Cell Host Microbe 10:423–425, 2011). Previous work in our groups has shown that a region of the streptococcal antigen denoted BAR (SspB Adherence Region) inhibits P. gingivalis/S. gordonii interaction and biofilm formation both in vitro and in a mouse model of periodontitis (Daep et al. in Infect Immun 74:5756–5762, 2006; Daep et al. in Infect immun 76:3273–3280, 2008; Daep et al. in Infect Immun 79:67–74, 2011). However, high localized concentration and prolonged exposure are needed for BAR to be an effective therapeutic in the oral cavity.MethodsTo address these challenges, we fabricated poly(lactic-co-glycolic acid) (PLGA) and methoxy-polyethylene glycol PLGA (mPEG-PLGA) nanoparticles (NPs) that encapsulate BAR peptide, and assessed the potency of BAR-encapsulated NPs to inhibit and disrupt in vitro two-species biofilms. In addition, the kinetics of BAR-encapsulated NPs were compared after different durations of exposure in a two-species biofilm model, against previously evaluated BAR-modified NPs and free BAR.ResultsBAR-encapsulated PLGA and mPEG-PLGA NPs potently inhibited biofilm formation (IC50 = 0.7 μM) and also disrupted established biofilms (IC50 = 1.3 μM) in a dose-dependent manner. In addition, BAR released during the first 2 h of administration potently inhibits biofilm formation, while a longer duration of 3 h is required to disrupt pre-existing biofilms.ConclusionsThese results suggest that BAR-encapsulated NPs provide a potent platform to inhibit (prevent) and disrupt (treat) P. gingivalis/S. gordonii biofilms, relative to free BAR.Electronic supplementary materialThe online version of this article (10.1186/s12951-018-0396-4) contains supplementary material, which is available to authorized users.

Rapid Release Polymeric Fibers for Inhibition of Porphyromonas gingivalis Adherence to Streptococcus gordonii

“…The fiber solution was subsequently vortexed, sonicated for 5 min, and dissolved for 1 h in a dark room. The quantity of extracted F-BAR was determined by measuring the fluorescence using a spectrophotometer (488/518 nm excitation/emission), relative to an F-BAR standard (Kalia et al, 2017;Mahmoud et al, 2018Mahmoud et al, , 2019. A standard curve of F-BAR was obtained by adding 0.1 mg F-BAR to 1 mL of 1:9 DMSO:TE, and serially diluting in 1:9 DMSO:TE.…”

“…The in vitro release of F-BAR from fibers was measured by gentle agitation of EFs in phosphate buffered saline (PBS, pH 7.4) at 37 • C. At fixed time points (1, 2, 4, 8, 12, and 24 h), samples were collected and the amount of F-BAR released from the EFs was quantified via fluorescence spectroscopy, against an F-BAR standard in PBS (Kalia et al, 2017;Tyo et al, 2017;Mahmoud et al, 2018).…”

“…GraphPad InStat (La Jolla, CA) was used for data analysis and differences were considered to be statistically significant when P ≤ 0.05. The percent inhibition of P. gingivalis adherence was calculated with the following formula: GR sample/GR control (Kalia et al, 2017;Mahmoud et al, 2018).…”

“…Established biofilms were administered BAR-EFs, free BAR or blank EFs at various concentrations in 1 mL PBS, and processed and analyzed as described above. The mean and standard deviation (SD) between samples were determined and the percent disruption of P. gingivalis adherence was calculated with the following formula: GR sample/GR control (Kalia et al, 2017;Mahmoud et al, 2018).…”

“…We previously showed that BAR-modified and BARencapsulated nanoparticles inhibit P. gingivalis biofilm formation (Kalia et al, 2017;Mahmoud et al, 2018Mahmoud et al, , 2019. These vehicles were envisioned to serve in formulations such as an oral gel, varnish or mouthwash that require two to three daily applications.…”