Complexation-induced resolution enhancement of 3D-printed hydrogel constructs

Abstract

Three-dimensional (3D) hydrogel printing enables production of volumetric architectures containing desired structures using programmed automation processes. Our study reports a unique method of resolution enhancement purely relying on post-printing treatment of hydrogel constructs. By immersing a 3D-printed patterned hydrogel consisting of a hydrophilic polyionic polymer network in a solution of polyions of the opposite net charge, shrinking can rapidly occur resulting in various degrees of reduced dimensions comparing to the original pattern. This phenomenon, caused by complex coacervation and water expulsion, enables us to reduce linear dimensions of printed constructs while maintaining cytocompatible conditions in a cell type-dependent manner. We anticipate our shrinking printing technology to find widespread applications in promoting the current 3D printing capacities for generating higher-resolution hydrogel-based structures without necessarily having to involve complex hardware upgrades or other printing parameter alterations.

An open-source handheld extruder loaded with pore-forming bioink for in situ wound dressing

“…The other aqueous phase was the PEO solution, which does not photocrosslink and subsequently forms a pore structure on removal. To prepare the GelMA solution, GelMA (high degree of methacryloyl substitution; conversion of amine groups: ~84%) was synthesized according to our previously reported protocol [ [21] , [22] , [23] ], and prepared at a final concentration of 10 wt% in phosphate-buffered saline (PBS; Thermo Fisher, USA) containing 0.5 wt% lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; Allevi, USA). PEO used had a molecular weight of 300,000 Da (Sigma-Aldrich, USA), and was prepared at a final concentration of 1.6 wt% in PBS.…”

Structural Innovations in Printed, Flexible, and Stretchable Electronics

“…[ 128 ] Special materials have been developed using shrinking polymer to obtain a sub‐micron resolution, and the assembly of various mesostructures with superior mechanical performance has also been proposed in various fabrication processes that can be translated and adapted for planar printing techniques. [ 129,130 ] Unlike the microfabrication‐based structures, most of the current printed structures are still lacking complementary mechanical studies that systematically summarize their behaviors. Due to the use of unconventional soft composite materials, mechanical studies based on rigid, nonviscoelastic materials cannot be generalized in these situations, and comprehensive studies focusing on the new materials are needed for gaining the insights necessary for guiding the development and improvement of printable structures.…”

3D printing of tissue engineering scaffolds: a focus on vascular regeneration

“…Transformation of the polymer from a planar structure to a 3D scaffold was created under a temperature field. Gong et al [ 185 ] fabricated vascular scaffolds with a certain diameter through 3D printing of hydrogels. Then the diameter of the scaffolds was reduced by complexation reaction, leading to resolution enhancement of the 3D printed constructs.…”