Metamaterials are featured by artificial composite structures with exotic properties, which process promising application potentials in various areas. However, the manufacturing of metamaterials faces great challenges due to the structural complexity, accuracy requirement, and small scale. Additive manufacturing (AM), as a layer-by-layer technique, shows intrinsic advantages in the fabrication of metamaterials. This paper extensively reviews the current state on how and to what extent AM techniques are adopted for metamaterials fabrication, in which the metamaterials are mainly classified into mechanical, acoustic and electromagnetic types. More importantly, the challenges and research opportunities are discussed for AM fabrication of metamaterials, with focus on high precision, multi-structural and multi-material, topology optimization, support structure, anisotropy and heterogeneity, residual stresses and application realization. It is expected that with further innovative solutions being developed to bridge the research gaps, the industries will become more confident to adopt metamaterials in devices and systems for critical applications.

DNA detection with high sensitivity and specificity has tremendous potential as molecular diagnostic agents. Graphene and graphene-based nanomaterials, such as graphene nanopore, graphene nanoribbon, graphene oxide, and reduced graphene oxide, graphene-nanoparticle composites, were demonstrated to have unique properties, which have attracted increasing interest towards the application of DNA detection with improved performance. This article comprehensively reviews the most recent trends in DNA detection based on graphene and graphene-related nanomaterials. Based on the current understanding, this review attempts to identify the future directions in which the field is likely to thrive, and stimulate more significant research in this subject.

This paper reviews the research progress of conductive hydrogel 3D printing for flexible electronics, with emphasis on 3D printing methods, classification and materials synthesis methods, and application fields.

The automobile industry is recognized as one of the most influential sectors shaping global economies, societies, and individual lifestyles. Therefore, fierce competition among different companies is continuously undergoing, and special attention is focused on innovations to improve competitiveness. In the past several years, additive manufacturing (AM) has emerged as an innovative technology in applications in the automobile industry with significant advantages over traditional techniques. As a result, increasing efforts have been paid to combining AM technology with the development of the automobile industry. Currently, many automobile players are optimizing their industrial layout by incorporating innovative AM techniques, and meanwhile, a lot of research progress has been achieved in order to meet the market demand. This article aims at presenting a timely review to conclude the recent advances in the application of AM techniques in the automobile industry, focusing on the available AM techniques, printable materials, and industry applications, based on which the advantages and disadvantages of each technique and material system are discussed in order to reveal the current application situation. The current research gaps and challenges are also outlined to indicate future research opportunities. Hopefully, this work can be useful to related researchers as well as game players in the industry of this field.

This work provides a comprehensive overview of recent advancements in mild aqueous Mg-ion batteries, covering their significant components such as electrolytes, cathode materials, intercalation anode materials, Mg metal anodes, and the full cell.