Tooth Diversity Underpins Future Biomimetic Replications.

Although the evolution of tooth structure seems highly conserved, remarkable diversity exists among species due to different living environments and survival requirements. Along with the conservation, this diversity of evolution allows for the optimized structures and functions of teeth under various service conditions, providing valuable resources for the rational design of biomimetic materials. In this review, we survey the current knowledge about teeth from representative mammals and aquatic animals, including human teeth, herbivore and carnivore teeth, shark teeth, calcite teeth in sea urchins, magnetite teeth in chitons, and transparent teeth in dragonfish, to name a few. The highlight of tooth diversity in terms of compositions, structures, properties, and functions may stimulate further efforts in the synthesis of tooth-inspired materials with enhanced mechanical performance and broader property sets. The state-of-the-art syntheses of enamel mimetics and their properties are briefly covered. We envision that future development in this field will need to take the advantage of both conservation and diversity of teeth. Our own view on the opportunities and key challenges in this pathway is presented with a focus on the hierarchical and gradient structures, multifunctional design, and precise and scalable synthesis.

A functional analysis of the effects of the molecular weight of dextran on ε-polylysine-dextran conjugate created through the maillard reaction.

The present study mainly examines the effects of molecular weight of dextran on the reaction rate and functional characteristics between ε-polylysine (PL) and dextran. The reaction kinetics, grafting degree and gel permeation chromatography are employed to evaluate the reaction rate and extent of these lard reaction. We find low activation energy (Ea) values that indicate that dextran with high molecular weight (HMD) exhibits a higher reaction rate with PL than that that of dextran with middle molecular weight (MMD) and low molecular weight (LMD). As for the functional characteristics of the formed conjugate, the conjugate of PL-HMD possesses a higher emulsifying activity, and PL-LMD exhibits higher antimicrobial activity than other molecular weight of dextran. We observe that long heating time at high temperatures can induce the partial degradation of the formed conjugates, which is reflected in the decreasing of the emulsifying and antimicrobial activity of PL-dextran conjugates.