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This study aimed to develop of a rapid and effective method to occlude dentinal tubules using carboxymethyl chitosan and lysozyme (CMC/LYZ) nanogels with encapsulated amorphous calcium phosphate (ACP) based on the transformation of ACP to HAP. In this work, CMC/LYZ was used to stabilize ACP and form CMC/LYZ-ACP nanogels, and then the nanogel-encapsulated ACP was applied to exposed dentinal tubule surfaces. The morphology of the nanogels was examined by transmission electron microscopy (TEM). Distribution and quantity of elements in CMC/LYZ-ACP nanogels were determined by element mapping and energy dispersive X-Ray spectroscopy (EDX). Scanning electron microscopy (SEM) images, XRD measurements and nanoindentation were applied to check the efficacy of tubular occlusion. TEM revealed that CMC/LYZ-ACP nanogels were spherical dense gel particles with size approximately 50-500 nm. Element mapping and EDX indicated that C, N, O, Ca, P, and S in the microspheres are thoroughly represented. SEM images shows that the thickness of the coating layer was approximately 1-2 μm and the depth to which the mineralized substance enters the dentinal tubule was approximately 4-8 μm. XRD measurements and nanoindentation indicated that the occluding mineralized substance observed were similar to nature dentin. CMC can form spherical dense nanogels loaded with ACP under the participation of lysozyme. The CMC/LYZ-ACP nanogels could increase the dentinal tubule occluding effectiveness. These results indicated that finding and developing novel nanomaterials of CMC/LYZ-ACP would be an effective strategy for the treatment of dentin hypersensitivity.

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Over the past few decades, nano-sized semiconductor powders for use as photocatalytic degradation of organic pollutants have attracted attention due to many advantages. In this research, a new composite material WO3-ZnO/molecular sieves (MS) was synthesized by precipitation method and hydrothermal method. The degradation activities of the WO3-ZnO/MS composite material were evaluated through photodegradation of methylene blue (MB). It was found that the degradation rate of MB increased with an increase in the time, and the composite material was effective for the decolorization of MB. The decolorization rate of MB increased with an increase in the material dosage. The decolorization rate of MB decreased with an increase in the initial concentration. The temperature affected the adsorption capacity of the composite material but the temperature had little effect on photodegradation. The results also indicated that MB was not easily decomposed under strong acid condition, while more easily under weakly acidic and alkaline conditions. Our results will serve as a foundation for future applications of photocatalytic degradation.