Biomaterials Science 2018-01-24

Liquid Crystalline Precursor Incorporating Chlorhexidine Acetate and Sliver Nanoparticles for Root Canal Disinfection

Tengyi Zheng, Xintian Huang, Jintian Chen, Disang Feng, Liling Mei, Ying Huang, Guilan Quan, Chune Zhu, Vikramjeet Singh, Hao Ran, Xin Pan, Chuanyu Wu, Chuanbin Wu

文献索引：10.1039/C7BM00764G

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摘要

Lyotropic liquid crystal (LLC) has received increasing attention as a drug delivery system. However, LLC is not comprehensively demonstrated as an intra-canal disinfectant. In this study, a novel intra-canal disinfectant based on glycerol monooleate (GMO) LLC precursor incorporating chlorhexidine (CHX) and silver nanoparticles (Ag-NP) were designed and evaluated. The LLC precursor with excellent fluidity could be able to deeply penetrate into the complex tiny collateral branch root canals. The transformation of cubic LLC in root canals upon contacting with water displays a thorough and long-lasting disinfection against multidrug-resistant bacteria to avoid endodontic reinfection and follow-up visits. The LLC precursor was optimized by its phase behaviour, rheological behaviour and drug release profiles. The GMO-ethanol (8/2) formulation containing 0.5% CHX and 0.02% Ag-NPs was selected for further studies. No changes in phase transition and rheological behaviour were observed in the presence of CHX and Ag-NP within the investigated dose range (CHX ≤ 0.5%, Ag-NP ≤ 0.02%, w/w). The low viscosity of the precursor presented excellent injectability and flowabilities. Additional in vitro release test displayed that the release behaviours were influenced by CHX and Ag-NP contents; allow the optimized precursor to obtain a 28-days release profile. CHX-Ag-NP containing LLC precursor exhibited an excellent and sustained sterilization effect on Enterococcus faecalis for more than one month with a bacterial inactivation rate ≥ 98.5%, which was far more than the minimum clinical requirement (7 days). Furthermore, no in vitro toxicity was observed in the cytotoxicity evaluation. The character of LLC as an intra-canal disinfectant was comprehensively demonstrated in this study, and CHX-Ag-NP-containing LLC precursor was proved to be a promising intra-canal disinfectant.