The dual anti‐caries effect of carboxymethyl chitosan nanogel loaded with chimeric lysin ClyR and amorphous calcium phosphate

In this study, we evaluated the anti‐biofilm and anti‐demineralization abilities of a novel material, CMC‐ClyR‐ACP nanogel, designed by loading the chimeric lysin ClyR and amorphous calcium phosphate (ACP) into a nanocarrier material carboxymethyl chitosan (CMC), in a demineralization model. Dynamic light scattering, transmission electron microscopy, and Fourier transmission infrared spectroscopy showed that CMC‐ClyR‐ACP nanogel was synthesized successfully. Enamel samples prepared from premolars were divided into five groups according to their treatments with: (i) double distilled water ddH2O, (ii) CMC‐ACP, (iii) CMC‐ClyR‐ACP, (iv) ClyR, or (v) 0.12% chlorhexidine. Streptococcus mutans was allowed to form biofilms on the teeth for two days before treatment procedures were carried out from day 3 to day 6. The relative biofilm viability analyzed by Cell Counting Kit‐8 showed that it was significantly lower (at 55.7%) for CMC‐ClyR‐ACP than seen for ddH2O (89.9%), which was consistent with result of confocal laser scanning microscopy. The percentage surface hardness loss of CMC‐ClyR‐ACP (29.2%) was significantly lower than that of CMC‐ACP (51.0%) and ClyR (58.7%) alone, and there was no significant difference between CMC‐ClyR‐ACP and chlorhexidine (26.9%), which was confirmed by scanning electron microscopy. Therefore, CMC‐ClyR‐ACP nanogel may be an effective strategy for the control of enamel demineralization.