Engineering Nitric Oxide-Releasing Antimicrobial Dental Coating for Targeted Gingival Therapy

Abstract

Bacterial biofilms play a central role in the development and progression of periodontitis, a chronic inflammatory condition that affects the oral cavity. One solution to current treatment constraints is using nitric oxide (NO)─with inherent antimicrobial properties. In this study, an antimicrobial coating is developed from the NO donor S-nitroso-N-acetylpenicillamine (SNAP) embedded within polyethylene glycol (PEG) to prevent periodontitis. The SNAP-PEG coating design enabled a controlled NO release, achieving tunable NO levels for more than 24 h. Testing the SNAP-PEG composite on dental floss showed its effectiveness as a uniform and bioactive coating. The coating exhibited antibacterial properties against Streptococcus mutans and Escherichia coli, with inhibition zones measuring up to 7.50 ± 0.28 and 14.80 ± 0.46 mm², respectively. Furthermore, SNAP-PEG coating materials were found to be stable when stored at room temperature, with 93.65% of SNAP remaining after 28 d. The coatings were biocompatible against HGF and hFOB 1.19 cells through a 24 h controlled release study. This study presents a facile method to utilize controlled NO release with dental antimicrobial coatings comprising SNAP-PEG. This coating can be easily applied to various substrates, providing a user-friendly approach for targeted self-care in managing gingival infections associated with periodontitis.

Keywords: antimicrobial coating; biofilm; dental pathogens; nitric oxide; periodontitis.

Figure 1

Schematic representation of NO-releasing dental floss for advanced care of the subgingival region. (A) NO-releasing floss is fabricated using a SNAP-PEG mixture coating. Various amounts of SNAP can be loaded into the mixture to enhance the tunability of NO release on the surface. (B) The versatility of the SNAP-PEG mixture is shown as solutions when heated to 60 °C and as a solid substrate at room temperature (23 °C). (C) Delivery of drugs using SNAP-PEG-coated dental floss involves a gradual transfer of SNAP from the floss onto the surfaces of teeth and the gingiva within the subgingival region during the flossing process. This results in the deposition of the coating into the periodontal pocket, enabling the sustained release of NO over an extended period.

Figure 2

(A) UV–vis spectroscopy absorption data were used to determine the concentration of each weight percent formulation incorporated (N = 5). (B) Determination of uniformity of the SNAP-PEG-coated NO-releasing floss to illustrate the uniformity in the fabrication (N = 16). An indirect drug efficiency study (C) drug delivery efficiency of SNAP-PEG-coated floss in depositing the coating between the teeth of a tooth model. (D) SEM Images show the morphology of the 1 wt % SNAP-PEG coating on floss before and after deposition of the coating in a tooth model. The scale bars represent 500 μm.

Figure 3

(A) Representative instantaneous NO release profiles of each weight percent of SNAP-PEG coating over a 30 h period (B) average NO flux recorded from 1, 5, and 10 wt % of SNAP-PEG coated dental floss at varying time points (0, 2, 6, and 30 h) reported as the mean ± SD determined using nitric oxide analyzer (N = 3). (C) The total nitrite concentration was used to estimate the NO-release in aqueous solution reported as the mean ± SD (N = 4). (D) Storage stability analysis of NO-releasing SNAP-PEG-coated floss over 28 days at room temperature (N = 3).

Figure 4

In vitro evaluation of NO-releasing SNAP-PEG coatings. (A) NO-releasing dental floss with inherent broad-spectrum antimicrobial properties can help in the prevention of periodontal infections. (B) Zone of inhibition studies were performed with S. mutans and E. coli. Final data are shown as mean ± SD (N = 5). Statistical significance is presented as ****(p <.0001). (C) Representational images of the zone of inhibition on agar plates for S. mutans and E. coli with the labels I–IV being the PEG control (I), 1 wt % (II), 5 wt % (III), and 10 wt % (IV) (D). Relative cell viability toward hFOB 1.19 and HGF cell lines. Data are presented as the mean percent viability normalized against untreated cells ± SD (N = 3).