Harnessing the antibacterial properties of chitosan to tackle dental biofilms

Description

INTRODUCTION
Dental biofilms are constituted by a community of microorganism that attach to the teeth surface resulting in the onset of dental diseases that to date are a global health concern. One of the main cariogenic bacterial species forming biofilms is Streptococcus mutans1. Carbohydrates are metabolized by the biofilm bacteria and produce acids responsible for the demineralization of the hard tissue of the teeth. Chitosan (CS), a natural biodegradable and biocompatible polysaccharide, has been reported to have good antibacterial effects due to
its positive charge. Fluoride has been used extensively as an anti-caries agent as it protects dental hard tissue from acid and inhibits bacterial growth of cariogenic species. We aim at combining these two strategies for the development of a novel agent able to reduce biofilm formation and demineralization.
MATERIALS & METHODS
Chitosan (CS) was degraded using hydrochloric acid into low molecular weight chitosan (CS3H) then modified with lysine (CS3H Lys). Fluoride was incorporated into the polymer by dialysis (CS3H Lys NaF). Polymers were characterised by NMR, FTIR, SEM and fluoro selective electrode was used to quantify the flouride. Streptococcus mutans biofilms were grown in biofilm medium (BM) containing 0.5 M sucrose in 5% CO2 at 37°C for 24h. The biofilm formation was quantified by staining with 0.1% crystal violet. The inhibition of acid demineralisation was determined using vanadomolybdate to measure the dissolution of phosphate by acid attack and measured at 450 nm.
RESULTS & DISCUSSION
The antibacterial and anti-biofilm activity of chitosan (CS) and modified chitosan (CS3H, CS3H Lys and CS3H Lys NaF) were determined against dental cariogenic bacteria S. mutans using both biofilm and planktonic methods to investigate the reduction of viable cells elicited by the polymers. The biofilm method showed that the modified chitosan (CS3H Lys and CS3H Lys NaF) reduced the S. mutans biofilm formation when compared with the original chitosan. The IC50 values of chitosan polymers against S. mutans biofilms were 121.8, 87.91, 21.24, 63.77 μg/ml, respectively. This study showed that addition the fluoride into polymer could protect demineralisation from acid attack. The percentage reduction of phosphate released were 0.72 ± 3.70, 4.68 ± 4.99, 28.79 ± 2.40, 33.76 ± 3.26, respectively.
CONCLUSION
These results show a good antibiofilm activity against S. mutans of CS3H Lys and the potential of CS3H Lys NaF to protect the teeth against demineralisation. A combination of these polymers can be used in the development of novel oral health products to control the formation of dental biofilms and stop the development of further dental diseases.
ACKNOWLEDGEMENTS
We would like to thank RISET-Pro, Ministry of Research, Technology and Higher Education of Republic Indonesia (World Bank Loan No.8245-ID) for the funding.
REFERENCES
[1] Hasibul, K et al., Molecular Medicine Reports, 17: 843-851, 2017.
[2] Cheung, R.C et al., Marine Drugs, 13(8):5156-5186, 2015.

Period	9 Jan 2019
Event title	RSC Biomaterials Chemistry Annual Conference 2019
Event type	Conference
Location	Liverpool, United KingdomShow on map