The use of additive manufacturing (AM) has moved well beyond prototyping and has been established as a highly versatile manufacturing method with demonstrated potential to completely transform traditional manufacturing in the future. In this paper, a comprehensive review and critical analyses of the recent advances and achievements in the field of different AM processes for polymers, their composites and nanocomposites, elastomers and multi materials, shape memory polymers and thermo-responsive materials are presented. Moreover, their applications in different fields such as bio-medical, electronics, textiles, and aerospace industries are also discussed. We conclude the article with an account of further research needs and future perspectives of AM process with polymeric materials.

Graphene is a two dimensional one atom thick allotrope of carbon that displays unusual crystal structure, electronic characteristics, charge transport behavior, optical clarity, physical & mechanical properties, thermal conductivity and much more that is yet to be discovered. Consequently, it has generated unprecedented excitement in the scientific community; and is of great interest to wide ranging industries including semiconductor, optoelectronics and printed electronics. Graphene is considered to be a next-generation conducting material with a remarkable band-gap structure, and has the potential to replace traditional electrode materials in optoelectronic devices. It has also been identified as one of the most promising materials for post-silicon electronics. For many such applications, modulation of the electrical and optical properties, together with tuning the band gap and the resulting work function of zero band gap graphene are critical in achieving the desired properties and outcome. In understanding the importance, a number of strategies including various functionalization, doping and hybridization have recently been identified and explored to successfully alter the work function of graphene. In this review we primarily highlight the different ways of surface modification, which have been used to specifically modify the band gap of graphene and its work function. This article focuses on the most recent perspectives, current trends and gives some indication of future challenges and possibilities.

Nanocellulosic materials, such as cellulose nanocrystals, cellulose nanofibers, and bacterial nanocellulose, that display high surface area, mechanical strength, biodegradability, and tunable surface chemistry have attracted great attention over the last decade for biomedical applications. Simultaneously, 3D printing is revolutionizing the field of biomedical engineering, which enables the fast and on-demand printing of customizable scaffolds, tissues, and organs. Nanocellulosic materials hold tremendous potential for 3D bioprinting due to their printability, their shear thinning behavior, their ability to live cell support and owing to their excellent biocompatibility. The amalgamation of nanocellulose-based feedstocks and 3D bioprinting is therefore of critical interest for the development of advanced functional 3D hydrogels. In this context, this review briefly discusses the most recent key developments and challenges in 3D bioprinting nanocellulose-based hydrogel constructs that have been successfully tested for mammalian cell viability and used in tissue engineering applications.

Intrinsically disordered proteins have dramatically changed the structure–function paradigm of proteins in the 21^st century. Resilin is a native elastic insect protein, which features intrinsically disordered structure, unusual multi-stimuli responsiveness and outstanding resilience. Advances in computational techniques, polypeptide synthesis methods and modular protein engineering routines have led to the development of novel resilin-like polypeptides (RLPs) including modular RLPs, expanding their applications in tissue engineering, drug delivery, bioimaging, biosensors, catalysis and bioelectronics. However, how the responsive behaviour of RLPs is encoded in the amino acid sequence level remains elusive. This review summarises the milestones of RLPs, and discusses the development of modular RLP-based biomaterials, their current applications, challenges and future perspectives. A perspective of future research is that sequence and responsiveness profiling of RLPs can provide a new platform for the design and development of new modular RLP-based biomaterials with programmable structure, properties and functions.

Plastic waste pollution, including non-biodegradable landfills, leaching of toxic chemicals into soil and waterways, and emission of toxic gases into the atmosphere, is significantly affecting our environment. Conventional plastic waste recycling approaches generally produce lower value materials compared to the original plastic or recover inefficient heat energy. Lately, upcycling or the valorization approach has emerged as a sustainable solution to transform plastic waste into value-added products. In this review, we present an overview of recent advancements in plastic waste upcycling, such as vitrimerization, nanocomposite fabrication, additive manufacturing, catalytic transformation, and industrial biotechnology, envisaged with technical challenges, future developments, and new circular economy opportunities.

Electrically conductive hydrogels (ECHs), an emerging class of biomaterials, have garnered tremendous attention due to their potential for a wide variety of biomedical applications, from tissue-engineered scaffolds to smart bioelectronics. Along with the development of new hydrogel systems, 3D printing of such ECHs is one of the most advanced approaches towards rapid fabrication of future biomedical implants and devices with versatile designs and tuneable functionalities. In this review, an overview of the state-of-the-art 3D printed ECHs comprising conductive polymers (polythiophene, polyaniline and polypyrrole) and/or conductive fillers (graphene, MXenes and liquid metals) is provided, with an insight into mechanisms of electrical conductivity and design considerations for tuneable physiochemical properties and biocompatibility. Recent advances in the formulation of 3D printable bioinks and their practical applications are discussed; current challenges and limitations of 3D printing of ECHs are identified; new 3D printing-based hybrid methods for selective deposition and fabrication of controlled nanostructures are highlighted; and finally, future directions are proposed.