A “Nonsolvent Quenching” Strategy for 3D Printing of Polysaccharide Scaffolds with Immunoregulatory Accuracy

Abstract

3D printing enables the customized design of implant structures for accurately regulating host responses. However, polysaccharides, as a major biomaterial category with versatile immune activities, are typically "non-printable" due to the collapse of their filaments extruded during printing. This challenge renders their potential as immunomodulatory scaffolds underexploited. Here, inspired by the quench hardening in metal processing, a nonsolvent quenching (NSQ) strategy is innovatively designed for the 3D printing of polysaccharides. Through rapid solvent exchanging, NSQ instantly induces surface hardening to strengthen the polysaccharide filaments upon extrusion, requiring neither chemical modification nor physical blending that alters the material properties. Tested with five polysaccharides with varying physicochemical properties, NSQ prints predesigned structures at organ-relevant scales and a long shelf-life over 3 months. Glucomannan scaffolds, fabricated via NSQ with different grid spacings (1.5 and 2.5 cm), induce distinct host responses upon murine subcutaneous implantation-from specific carbohydrate receptor activation to differential immunocytes accumulation and tissue matrix remodeling-as mechanistically validated in wild-type and Tlr2 −/− knockout mice. Overall, NSQ as a facile and generic strategy is demonstrated to fabricate polysaccharide scaffolds with improved shape fidelity, thereby potentially unmasking their accurate immunomodulatory activities for future biomaterials design.

Tissue-engineered edible bird’s nests (TeeBN)

“…A Pr close to 1 indicates an optimal printing condition. At the same time, its value <1 and >1 suggests the collapse of printing structure and closure of the circle; contrarily, the printing ink is the over concentrated inducing irregular shape of the structure ( ) [ 15 ] . After testing 91 combinations, we eventually obtained four categories of conditions: printable, shapeless, congested, and non-printable ( Figure 2E ); the samples with a Pr around 1 in red rectangles and printing sample shown in Figure 2F .…”

“…The modulus of GelMA samples was analyzed by Discovery HR-2 rheometer (TA Instruments, New Castle, USA) following a previously described method [ 15 ] . For flow sweep, the rheology study was carried out at room temperature.…”

“…GelMA ink, with 0.25% (w/v) photoinitiator lithium phenyl-2, 4, 6-trimethyl-benzoyl phosphinate (LAP), was loaded into preheated cartridges (26°C) and printed at 4 mm/s through a 27 G, 410 μm conical needle to a cooled receiving platform (4°C). The final hydrogel scaffold was crosslinked under 405 nm blue light for 10 s. 3D models for grids and discs were processed with GeSiM Robotics version 1.16.0.3892 [ 15 ] .…”

Covalent Bond Interfacial Recognition of Polysaccharides/Silica Reinforced High Internal Phase Pickering Emulsions for 3D Printing

“…Although polysaccharides are well-suited as “soft” colloidal emulsifiers for stabilizing HIPPEs with biodegradability, most polysaccharides still lack sufficient intermolecular binding to resist postprint collapse during extrusion. Reinforcement of intermolecular binding interaction and interfacial film thickness are effective strategies to improve the viscoelastic properties and the long-term stability of polysaccharide-based HIPPEs. , Based on the molecular rearrangement and characteristics such as flexible molecular entanglement chains of carboxymethyl chitosan (CMCS), three layers of jammed networks that fixed the oil droplets enmeshed therein were formed, further developing self-supported gel-like HIPPEs under various conditions . The irreversible adsorption of rodlike chitin nanofibrils at the interface and highly interconnected fibrillar networks structure in the continuous phase were designed to promote HIPPEs suitable for 3DP effectively .…”

Differential Foreign Body Reactions between Branched and Linear Glucomannan Scaffolds

“…This study explores the importance of structural arrangement in triggering immune responses. Two natural polysaccharides, linear-chain KGM and branched-chain BSP, were selected due to their similarities in composition and molecular weight [25,26]. Modification by acetylation was performed to increase their biological activity and hydrophobicity to facilitate scaffold preparation.…”