Chakraborty Anupam, Parveen Saida, Chanda Dipak Kr, Aditya Gautam
Department of Zoology, University of Calcutta 35 Ballygunge Circular Road Kolkata 700019 India
Department of Zoology, The University of Burdwan Golapbag Burdwan 713104 India
RSC Adv. 2020 Aug 11;10(49):29543-29554. doi: 10.1039/d0ra04271d. eCollection 2020 Aug 5.
The shell of the freshwater mussel (Mollusca: Bivalvia) is a composite biological material linked with multifunctional roles in sustaining ecosystem services. Apart from providing mechanical strength and support, the shell is an important site for adherence and growth of multiple types of algae and periphyton. Variations in the shell architecture are observed in the mussels both within a species and among different species. Considering the prospective utility of the shell of the freshwater mussels as a biological material, an assessment of the shell characteristics was accomplished using and as model species. The calcium carbonate (CaCO) content of the shells, physical features and mechanical strength were assessed along with the morphometric analysis. The CaCO content of the shell (upto 95% to 96% of the shell weight) of both the mussels was positively correlated with the shell length, suggesting increased deposition of CaCO in shells with the growth of the species. The cross sectioned views of FE-SEM images of the shells exhibited distinct layered structure with external periostracum and inner nacreous layer varying distinctly. In the growing region, the growth line was prominent in the mussel shells revealed through the FESEM images. In addition XRD, FTIR and EDS studies on the mussel shells confirmed the existence of both aragonite and calcite forms of the calcium carbonate crystals with the incidence of various functional groups. The mechanical strength of the mussel shells was explored through nanoindentation experiments, revealed significant strength at the nanoparticle level of the shells. It was apparent from the results that the shell of the freshwater mussel and qualify as a biological material with prospective multiple applications for human well-being and sustaining environmental quality.
淡水贻贝（软体动物：双壳纲）的外壳是一种复合生物材料，在维持生态系统服务方面具有多种功能。除了提供机械强度和支撑外，外壳还是多种藻类和周丛生物附着和生长的重要场所。在贻贝物种内部和不同物种之间都观察到外壳结构的变化。考虑到淡水贻贝壳作为生物材料的潜在用途，以[具体物种1]和[具体物种2]为模型物种对壳的特性进行了评估。对壳的碳酸钙（CaCO₃）含量、物理特征和机械强度以及形态分析进行了评估。两种贻贝壳的碳酸钙含量（高达壳重的95%至96%）与壳长呈正相关，表明随着物种生长，壳中碳酸钙的沉积增加。壳的场发射扫描电子显微镜（FE-SEM）图像的横截面视图显示出明显的分层结构，外部角质层和内部珍珠层明显不同。在生长区域，通过FESEM图像可以看出贻贝壳中的生长线很突出。此外，对贻贝壳的X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和能谱分析（EDS）研究证实了碳酸钙晶体的文石和方解石形式的存在以及各种官能团的存在。通过纳米压痕实验探索了贻贝壳的机械强度，结果表明壳在纳米颗粒水平具有显著强度。结果表明，淡水贻贝[具体物种1]和[具体物种2]的壳可作为一种生物材料，对人类福祉和维持环境质量具有潜在的多种应用。
