Diatom frustules, considered as novel bio-functional materials, display a diversity of patterns and unique micro-and nanostructures which may be useful in many areas of application. Existing devices directly use the original structure of the biosilica frustules, limiting their function and structural scale. Current research into the shapes, materials and structural properties of frustules are considered; a series of frustule processing methods including structure processing, material modification, bonding and assembly techniques are reviewed and discussed. The aim is to improve the function of diatom frustules allowing them to meet the design requirements of different types of micro devices. In addition, the importance of the comprehensive use of diatom processing methods in device research is discussed using biosensors and solar cells as examples, and the potential of bio-manufacturing technology based on diatom frustules is examined. Nature presents a wide range of functional structures. Particularly at the micro-and nanoscale, the complexity and functionality of biological structures are far greater than those of equivalent artificial devices, making these biological structures an appropriate subject for biotechnology and bio-manufacturing [1,2]. In our previous studies, we have reported bio-limited forming [3] and bio-replication forming [4,5] methods for manufacturing functional particles or surface morphology from biological structures. Micro devices with highly desirable structure and characteristics could be produced from biological micro-or nanostructures. Single-celled diatoms are widely distributed in rivers, lakes and other water bodies, and have a fast (exponential) reproductive rate. The cell wall of a diatom known as the frustule, has a transparent structure composed of amorphous silica [6]. The frustule has good mechanical strength [7,8], a variety of three-dimensional (3D) shapes [9,10], multi-level nanopores and microstructures [11,12], large surface area and unique optical properties [13][14][15], making it a potential novel functional material for bio-manufacturing. Studies on theoretical understanding, manufacturing methods and functionalization of diatom frustules are ongoing. In the last two centuries, the importance of diatom frustules in the field of micro-and nanotechnology has become increasingly evident. The potential of frustules has been extensively explored by academics and for commercial application. The resulting new theories and techniques have found wide application, leading to the formation of a new interdisciplinary area of research called diatom-based bio-nanotechnology (or diatom nanotechnology) [16][17][18][19][20][21]. The potential for diatoms in device applications, such as high-sensitivity gas sensors [22], drug delivery devices [23], biocarriers for biosensors [24][25][26][27], micro-filters [12,28], solar cells, battery electrodes and electroluminescent display devices [19] has been examined. However, the direct
