Abalone water-soluble matrix for self-healing biomineralization of tooth defects

Bottom-Up Assembling Hierarchical Enamel-Like Bulk Materials with Excellent Optical and Mechanical Properties for Tooth Restoration

Enamel has good optical and mechanical properties because of its multiscale hierarchical structure. Biomimetic construction of enamel-like 3D bulk materials at nano-, micro-, mesh- and macro-levels is a challenge. A novel facile, cost-effective, and easy large-scale bottom-up assembly strategy to align 1D hydroxyapatite (HA) nanowires bundles to 3D hierarchical enamel structure with the nanowires bundles layer-by-layer interweaving orientation, is reported. In the strategy, the surface of oleate templated ultralong HA nanowires with a large aspect ratio is functionalized with amphiphilic 10-methacryloyloxydecyl dihydrogen phosphate (MDP). Furtherly, the MDP functionalized HA nanowire bundles are assembled layer-by-layer with oriented fibers in a single layer and cross-locked between layers at a certain angle at mesoscale and macroscale in the viscous bisphenol A-glycidyl methacrylate (Bis-GMA) ethanol solution by shear force induced by simple agitation and high-speed centrifugation. Finally, the excessive Bis-GMA and ethanol are removed, and (Bis-GMA)-(MDP-HA nanowire bundle) matrix is densely packed under hot pressing and polymerized to form bulk enamel-like materials. The composite has superior optical properties and comparable comprehensive mechanic performances through a combination of strength, hardness, toughness, and friction. This method may open new avenues for controlling the nanowires assembly to develop hierarchical nanomaterials with superior properties for many different applications.

Nanohydroxyapatite/Peptide Composite Coatings on Pure Titanium Surfaces with Nanonetwork Structures Using Oyster Shells

Titanium and its alloys are extensively applied in artificial tooth roots because of their excellent corrosion resistance, high specific strength, and low elastic modulus. However, because of their biological inertness, their surface needs to be modified to improve the osteointegration of titanium implants. The preparation of biologically active calcium-phosphorus coatings on the surface of an implant is one effective method for enhancing the likelihood of bone integration. In this study, osteoinductive peptides were extracted from oyster shells by using acetic acid. Two peptide-containing hydroxyapatite (HA) composite coatings were then prepared: one coating was prepared by hydrothermally synthesizing an HA coating in the presence of peptides (HA/P/M), and the other coating was prepared by hydrothermally synthesizing HA and then immersing the hydrothermally synthesized HA in a peptide solution (HA/P/S). Characterization results indicated that the composite HA coatings containing oyster shell-based peptides were successfully prepared on the alkali-treated pure titanium surfaces. The HA/P/M and HA/P/S composite coatings were found to exhibit excellent hydrophilicity. Protein adsorption tests confirmed that the HA/P/M and HA/P/S coatings had an approximately 2.3 times higher concentration of adsorbed proteins than the pure HA coating.

Overview of structure, function and integrated utilization of marine shell

Marine shell resources have received great attention from researchers owing to their unique merits such as high hardness, good toughness, corrosion resistance, high adsorption, and bioactivity. Restricted by the level of comprehensive utilization technology, the utilization rate of shells is extremely low, resulting in serious waste and pollution. The research shows that the unique brick-mud structure of shells makes them have diverse and good functional characteristics, which guides them to have great utilization potential in different fields. Hence, this review highlights the constitutive relationship between microstructure-function-application of shells (e.g., gastropods, cephalopods, and amniotes), and the comprehensive applications and development ideas in the fields of biomedicine, adsorption enrichment, pHotocatalysis, marine carbon sink, and environmental deicer. It is worth mentioning that marine shells are currently well developed in three areas: bone repair, health care and medicinal value, and drug carrier, which together promote the progress of biomedical field. In addition, an in-depth summary of the application of marine shells in the adsorption and purification of various impurities such as crude oil, heavy metal ions and dyes at low-cost and high efficiency is presented. Finally, by integrating thoughts and approaches from different applications, we are committed to providing new pathways for the excavation and future high-value of shell resources, clarifying the existing development stages and bottlenecks, promoting the development of related technology industries, and achieving the synergistic win-win situation of economic and environmental benefits.

Advanced materials for enamel remineralization

Dental caries, a chronic and irreversible disease caused by caries-causing bacteria, has been listed as one of the three major human diseases to be prevented and treated. Therefore, it is critical to effectively stop the development of enamel caries. Remineralization treatment can control the progression of caries by inhibiting and reversing enamel demineralization at an early stage. In this process, functional materials guide the deposition of minerals on the damaged enamel, and the structure and hardness of the enamel are then restored. These remineralization materials have great potential for clinical application. In this review, advanced materials for enamel remineralization were briefly summarized, furthermore, an outlook on the perspective of remineralization materials were addressed.

Green efficient ultrasonic-assisted extraction of abalone nacre water-soluble organic matrix for bioinspired enamel remineralization

Reconstructing enamel-like hydroxyapatite structures on damaged teeth remains a great challenge in the materials science and dentistry due to its highly ordered hierarchical microstructure. Inspired by the mineralization of mollusk nacre in nature, abalone nacre water-soluble organic matrix (WSM) was isolated successfully though an ultrasonic-assisted water extraction (UWE) strategy with nondestructive activity and high-quality extraction for simulating the process of tooth hard tissue mineralization. Results showed that the UWE strategy significantly increased the protein yield from 7.60% to 9.60% and improved the polysaccharide yield from 2.59% to 3.34%, respectively, indicating its excellent extraction efficiency of WSM. Noteworthily, the smallest averaged particle size (~155 nm) of WSM were obtained at an ultrasound time of 6 h, whereas the highest absolute values (~ -32 mV) of zeta potential was produced. Moreover, it was proved that WSM could induce the growth of enamel-like hydroxyapatite crystals to further facilitate biomimetic remineralization of the demineralized enamel and restore its continuous and smooth surface structure in vitro. Besides, the hardness (4.37 ± 0.07 GPa) and modulus of elasticity (84.80 ± 1.49 GPa) of the WSM-repaired enamel was similar to that of native enamel, indicating superior mechanical properties after repair. Herein, it provides a promising green, efficient strategy for the remineralization of damaged enamel and high value utilization of waste abalone shells.

Preparation and characterization of abalone shells derived biological mesoporous hydroxyapatite microspheres for drug delivery

The rapid growth of the abalone industry has brought a great burden to the environment because of their inedible shells. Aiming at environmental and resource sustainability, porous microspheres of carbonate-substituted hydroxyapatite (HAP) were prepared by a hydrothermal method using abalone shells; then, they were further used as a carrier for doxorubicin (DOX) in a drug delivery system. The porous HAP microspheres were approximately 6 μm in size with a considerable specific surface area and average pore size (128.6659 cm²/g and 9.064 nm, respectively), which ensured excellent drug-handling capacity (95.542%). In addition, the pH responsiveness of the drug release system was favorable for effective in vivo drug release in an acidic tumor microenvironment. Moreover, the drug-loaded microspheres could effectively induce apoptosis of MCF-7 cells but were less cytotoxic to MC3T3-E1 cells. Because of its good biocompatibility, high drug loading capacity and controlled drug release property, the porous microspheres prepared in this experiment have potential application value in drug delivery and tumor therapy; furthermore, they make full use of abalone shells, providing environmental sustainability.

Effect of different cooking methods on the content and bioaccessibility of iodine components in abalone (Haliotis discus hannai)

The present study aimed to evaluate the changes in total iodine and iodine species (iodide, iodate, 3-iodo-l-tyrosine, and 3,5-diiodo-l-tyrosine) content in abalone after different treatments (raw, semi-drying, steaming, grilling, and boiling) and in-vitro digestion using high-performance liquid chromatography-inductively coupled plasma-mass spectroscopy (HPLC-ICP-MS). The highest reduction in iodine content was found in boiled abalone (64.95%), followed by steamed (32.40%) and grilled (32.11%) abalones. There is no significant difference between iodine content of raw and semi-dried abalone. Absorption efficiency was determined by an in vitro digestion procedure using simulated gastro/intestinal solutions. Unlike total iodine content after cooking, absorption efficiency increased after cooking. Absorption efficiency of semi-dried abalone is the highest (28.53%), followed by boiled (23.85%), grilled (22.62%), steamed (21.51%), and raw (12.20%) abalones. Iodide was the major form of iodine present in the abalone after cooking and in vitro digestion. No iodate was observed, and the organic iodine content was very low.