Effect of pH-sensitive nanoparticles on inhibiting oral biofilms.

Dental caries is a biofilm-related preventable infectious disease caused by interactions between the oral bacteria and the host's dietary sugars. As the microenvironments in cariogenic biofilms are often acidic, pH-sensitive drug delivery systems have become innovative materials for dental caries prevention in recent years. In the present study, poly(DMAEMA-co-HEMA) was used as a pH-sensitive carrier to synthesize a chlorhexidine (CHX)-loaded nanomaterial (p(DH)@CHX). In vitro, p(DH)@CHX exhibited good pH sensitivity and a sustained and high CHX release rate in the acidic environment. It also exhibited lower cytotoxicity against human oral keratinocytes (HOKs) compared to free CHX. Besides, compared with free CHX, p(DH)@CHX showed the same antibacterial effects on S. mutans biofilms. In addition, it had no effect on eradicating healthy saliva-derived biofilm, while free CHX exhibited an inhibitory effect. Furthermore, the 16s rDNA sequencing results showed that p(DH)@CHX had the potential to alter oral microbiota composition and possibly reduce caries risk. In conclusion, the present study presents an alternative option to design an intelligent material to prevent and treat dental caries.

Advances in Treponema denticola and oral diseases / 口腔疾病防治

@#Treponema denticola is an important pathogenic Treponema pathogen in the human oral cavity. Early studies have found that Treponema denticola is closely related to the occurrence and development of periodontal diseases. With the development of technical methods in recent years, many studies have shown that Treponema denticola not only can participate in periodontal diseases through a variety of mechanisms but also can play an important role in the development of various oral diseases. Treponema denticola is detected in high concentrations in peri-apical diseases and peri-implant diseases, and its surface protein is also prevalent in oral tumor samples. This paper reviews the research progress of Treponema denticola in periodontal diseases, pulp peri-apical diseases, peri-implant diseases and oral tumors, and summarizes the relevant mechanisms. For example, Treponema denticola can cause immune regulation disorder, destroy the epithelial barrier, induce bone absorption, promote the occurrence and development of inflammation through a variety of surface proteins, including chymotrypsin-like protease complex (CTLP), major outer sheath protein (Mosp), Td92, and LOS. It can also escape complement-mediated killing effects through surface FhbB lipoproteins and promote the occurrence and development of oral tumors by regulating the tumor microenvironment. These theories provide a theoretical basis for further understanding the development of oral diseases, controlling the infection of Treponema denticola, and exploring more effective treatment strategies.

[Microbial degradation of polyurethane plastics].

Plastic pollution has become a global environmental issue, making it necessary to explore the environmental disposal technology for plastic waste. Recently, we and other researchers have individually found microorganisms or enzymes from nature that can degrade synthetic plastic. These findings indicated that the capability of these microorganisms or enzymes to degrade plastic could be used for the disposal of plastic waste. Polyurethane (PUR) was one of the most used general plastic and its plastic waste occupied 30% of the total volume of different plastic waste. This review tried to provide a comprehensive summary of the researches on microbial degradation of PUR plastic in the past 70 years since its invention, and focused on the PUR-degrading fungi, bacteria, genes or enzymes, degradation products and the corresponding biological disposal technologies. We finally proposed the key scientific challenges on the development of high efficient biological disposal for PUR waste in the perspective researches.