Preparation of a photocurable hydrogel with adjustable mechanical properties for 3D printing

Abstract

Purpose This paper aims to show a series of hydrogels with adjustable mechanical properties, which can be cured quickly with visible light. The hydrogel is prepared conveniently with hydroxyethyl acrylate, cross-linker, gelatin and photoinitiator, and can be printed into certain 3D patterns with the direct ink write (DIW) 3D printer designed and developed by the research group. Design/methodology/approach In this paper, the authors designed a composite sensitization initiation system that is suitable for hydrogels. The concentration of photoinitiator, gelatin and cross-linker was studied to optimize the curing efficiency and adjust the mechanical properties. A DIW 3D printer was designed for the printing of hydrogel. Pre-gel solution was loaded into printer for printing into established models. The models were made and sliced with software. Findings The hydrogels can be cured efficiently with 405-nm visible light. While adding various content of gelatin and cross-linker, the mechanical properties of hydrogels show from soft and fragile (elastic modulus of 121.18 kPa and work of tension of 218.11 kJ·m−3) to rigid and tough (elastic modulus of 505.15 kPa and work of tension of 969.00 kJ·m−3). The hydrogels have high capacity of water absorption. With the DIW 3D printer, pre-gel hydrogel solution can be printed into objects with certain dimension. Originality/value In this work, a composite sensitization initiation system was designed, and fast curing hydrogels with adjustable mechanical properties had been prepared conveniently, which has high equilibrium water content and 3D printability with the DIW 3D printer.

Three-Dimensional Printing Strategies for Enhanced Hydrogel Applications

“…A pivotal area of focus is on the mechanical properties and structural integrity of hydrogels, with a significant body of work [2,22,23,49,56,57,59,60,62,65,[71][72][73][74]80] emphasizing the evaluation of tensile strength, compressive strength, elasticity, toughness, and viscoelastic properties. This emphasis is crucial for applications where mechanical integrity is paramount, such as tissue engineering scaffolds [119,121,122,129] and soft robotics [63].…”

“…The field is advancing through novel crosslinking methods [15,18,19] and the incorporation of functional materials [69][70][71], aiming to strike a balance between strength, biocompatibility, and biodegradability. Enhanced bioprinting techniques [74][75][76] and the integration of bioactive molecules [60,72,73] are paving the way for more intricate and functional tissue constructs. The development of smart and responsive hydrogels [77][78][79] heralds new prospects for medical devices and drug delivery systems.…”

Recent progress in the development of conductive hydrogels and the application in 3D printed wearable sensors

“…After printing, in order to enhance the robustness of the model and prevent deformation caused by flow, further curing crosslinking will be carried out in different ways, such as photocuring, thermal-curing and pH response. 181,182 Compared with the first one, the thixotropy requirement of the second method is not so high. However, initiators related to crosslinking conditions need to be added.…”