3D printing alias additive manufacturing can transform 3D virtual models created by computer-aided design (CAD) into physical 3D objects in a layer-by-layer manner dispensing with conventional molding or machining. Since the incipiency, significant advancements have been achieved in understanding the process of 3D printing and the relationship of component, structure, property and application of the created objects. Because hydrogels are one of the most feasible classes of ink materials for 3D printing and this field has been rapidly advancing, this Review focuses on hydrogel designs and development of advanced hydrogel-based biomaterial inks and bioinks for 3D printing. It covers 3D printing techniques including laser printing (stereolithography, two-photon polymerization), extrusion printing (3D plotting, direct ink writing), inkjet printing, 3D bioprinting, 4D printing and 4D bioprinting. It provides a comprehensive overview and discussion of the tailorability of material, mechanical, physical, chemical and biological properties of hydrogels to enable advanced hydrogel designs for 3D printing. The range of hydrogel-forming polymers covered encompasses biopolymers, synthetic polymers, polymer blends, nanocomposites, functional polymers, and cell-laden systems. The representative biomedical applications selected demonstrate how hydrogel-based 3D printing is being exploited in tissue engineering, regenerative medicine, cancer research, in vitro disease modeling, high-throughput drug screening, surgical preparation, soft robotics and flexible wearable electronics. Incomparable by thermoplastics, thermosets, ceramics and metals, hydrogel-based 3D printing is playing a pivotal role in the design and creation of advanced functional (bio)systems in a customizable way. An outlook on future directions of hydrogel-based 3D printing is presented.

3D printing of hydrogels: Rational design strategies and emerging biomedical applications

Recent advances in surface-modified cellulose nanofibrils

Phase entropy as a function of lithium filling in the layered oxide S = KB ln(Ω) , Boltzman configuration entropy With Ω the configuration multiplicity (number of ways the inserted lithium cations could be arranged in the host lattice). Under the reasonable assumption of indistinguishable lithium cations, the configuration multiplicity of N lithium cations into the host material with Ns effective total number of sites follows the combinatorial equation below: Notes by MIT Student (and MZB)

Lithium Ion Batteries

Recent advances in chitin based materials constructed via physical methods

Chitosan-based hydrogel beads: Preparations, modifications and applications in food and agriculture sectors - A review.

Cellulose, lignin and lignocellulose are important bioresources in the nature. Their effective and environmentally friendly utilization not only reduces dependence on fossil resources but also protects the environment. Recently, a class of novel eco-friendly solvents, ionic liquids, is employed to dissolve and process these bioresources. In this mini-review, we summarized the recent advances of processing and valorization of cellulose, lignin and lignocellulose in ionic liquids. It is expected that this up-to-date survey provides a comprehensive information of this field, and accelerates the development and utilization of the renewable plant biomass resources.

Processing and valorization of cellulose, lignin and lignocellulose using ionic liquids

Pullulan dialdehyde crosslinked gelatin hydrogels with high strength for biomedical applications.

Dissolution and regeneration of collagen fibers using ionic liquid

Heat sealable soluble soybean polysaccharide/gelatin blend edible films for food packaging applications

Efficient removal of anionic dye (Congo red) by dialdehyde microfibrillated cellulose/chitosan composite film with significantly improved stability in dye solution.

Xuejing Zheng

Papers

Processing and valorization of cellulose, lignin and lignocellulose using ionic liquids

Pullulan dialdehyde crosslinked gelatin hydrogels with high strength for biomedical applications.

Dissolution and regeneration of collagen fibers using ionic liquid

Heat sealable soluble soybean polysaccharide/gelatin blend edible films for food packaging applications

Efficient removal of anionic dye (Congo red) by dialdehyde microfibrillated cellulose/chitosan composite film with significantly improved stability in dye solution.