Table 13.
Biomaterial passport: Molluscan shell.
| Scientific Name | Molluscan Shells |
|---|---|
| Chemical structure, MW | Mostly composed of CaCO3, MW: 100.1 g/mol [377]. |
| Physicochemical properties | Molluscan shells are stable, exhibiting a high degree of morphological and crystallographic ordering [378] resulting in high values of the elastic modulus and bending strength (up to 82 GPa and 267 MPa, respectively) [379,380]. Importantly, the quality of the shell and its physical properties depend on environmental conditions [381]. High temperature treatment of shells leads to the conversion of CaCO3 to calcium oxide (CaO) [382] or it can be converted to hydroxyapatite by the hydrothermal method [383]. |
| Molluscan shell extraction/Physical form after extraction | In general, molluscan shells are collected as aquaculture industry waste byproduct and are further processed [384]. Physical forms of shells include shell fragments and powders [384]. |
| Biomaterials properties (biocompatibility, biodegradability, toxicity, immune responses) | Molluscan shell derived materials are considered to be biocompatible [385]. The nacre was reported to be biocompatible, biodegradable and exhibit osteogenic properties [386]. Furthermore, it showed limited cytotoxicity [387] and did not elicit immune responses [388]. The nacre exhibits outstanding mechanical properties which are species dependent (Pincfada: tensile strength of 140–170 MPa, Young’s modulus of 60–70 GPa; Hydnum rufescens: tensile strength of 180 ± 20 MPa; Pinctada margaritifera: tensile strength of 220 ± 60 MPa) [386]. |
| Market situation (world market reports) | The variety of molluscan shells applications (poultry food, pet nutrition liming agents) created a market of potentially increasing demand [389]. The development of shell valorisation methods will be crucial for the market stabilization [384]. |
| Patents | Currently, about several hundreds of patents related to various application of molluscan shells (building material component, bone graft material, decontaminants) or nacre itself (composites, cosmetic ingredients) exist. |
| For search, use: https://patents.google.com/ | |
| Selected examples: | |
| CN101971982A. Oyster shell powder containing hydrogen and manufacture method thereof | |
| CN106866807A. The preparation method of pearl protein, the pearl protein prepared by the method and its application | |
| WO2008017962A8. Microcapsules with improved shells | |
| KR101357078B1. Process for seperation of cutoffs having anti-inflamentary or osteoarthritis inhibition effects using oyster shells | |
| KR101771055B1. Composition comprising water-soluble pearl powder for skin whitening, anti-inflammation and anti-aging | |
| UDS 5968772. Pearl protein (nacrein) and process for producing the same | |
| US4312099A. Process for shucking a mollusk | |
| US8067078B1. Nacre composites, methods of synthesis, and methods of use | |
| US 6251438. Method of preparing active substances from nacre, products obtained which can be used in particular as medicaments | |
| FR2777190B1. Extraction process, identification of the active ingredients contained in the internal and external shell of sea molluscs, their use in people-based thera, diagnosis and cosmetic preparations | |
| FR2799125B1. Process for the preparation of a composition by extraction of nacre, comprising the complete components of the nacre, composition obtained by this process and its use in pharmacy and cosmetics. | |
| FR2899478A1. Process for extracting nacre molecules, compositions and use | |
| US8162241B2. Apparatus and method for collecting and crushing seashells on a beach | |
| US4939814A.Cultured mussel cleaning machine | |
| WO1997015398A1.Method for producing a lime product from mussel- and/or seashells |