3D printable fungi-based Chitin nanofiber/CNC hydrogels: implication for fabrication of functional cryogels

Abstract

Fungal-derived chitin nanofibers represent a naturally abundant and renewable material with considerable mechanical strength, making them a promising candidate for advanced material applications. However, their application in 3D printing remains in the early stages of research, as pure fungal chitin hydrogels exhibit poor printability that limits their use in additive manufacturing. In our study, we address this challenge by incorporating cellulose nanocrystals (CNCs) into the chitin-based hydrogels. The addition of CNCs effectively fine-tunes the rheological properties of the chitin-based hydrogels, enabling stable extrusion-based 3D printing while preserving the structural integrity of the material. This approach allowed us to formulate a range of high-fidelity printing inks by hybridizing these bio-based nanomaterials, ultimately creating sustainable aerogels that are ideal for divers applications. Moreover, while CNC aerogels often suffer from insufficient mechanical strength and poor handling characteristics, hybridizing them with chitin nanofibers results in robust, well-structured aerogels. Compression tests confirmed that the mechanical strength of these aerogels is predominantly dictated by chitin network, with CNCs contributing significantly to improved printability and enhanced structural uniformity. To further expand the functional properties of these hybrid aerogels, we incorporated multi-wall carbon nanotubes (MWCNTs) to impart electrical conductivity, thereby enabling their use in electromagnetic interference (EMI) shielding applications. Electrical conductivity measurements demonstrated excellent charge transport capabilities, resulting in a total EMI shielding effectiveness of 34 dB over the X-band frequency range (8–12 GHz). Overall, this study highlights the tremendous potential of fungal-derived, 3D printable chitin aerogels as sustainable, lightweight substrates, offering an eco-friendly alternative to conventional synthetic composites for applications ranging from wound dressings to EMI shielding devices.