Digital light processing 3D printing of hydrogels: a minireview

Abstract

The rapid development of three-dimensional (3D) printing hydrogel materials into sophisticated constructs has led to considerable progress in the fields of tissue engineering, soft actuators/robots, flexible electronics, etc. Notably, digital...

Recent progress in fabrications and applications of functional hydrogel films

“…DLP printing employs a layer‐by‐layer polymerization process, in which hydrogel thin layers can be fabricated in less than 1 min. More importantly, spatiotemporal light control in the DLP allows controlling the degree of curing, consequently the material properties gradient along in‐plane and through‐plane directions in a pixelated manner 72–78 . For example, grayscale photo‐printing uses omnidirectional light control to introduce material heterogeneity into a photo curable materials and allows the production of hydrogels with varied properties using the single vat of resin (Figure 3A).…”

“…More importantly, spatiotemporal light control in the DLP allows controlling the degree of curing, consequently the material properties gradient along inplane and through-plane directions in a pixelated manner. [72][73][74][75][76][77][78] For example, grayscale photo-printing uses omnidirectional light control to introduce material heterogeneity into a photo curable materials and allows the production of hydrogels with varied properties using the single vat of resin (Figure 3A). 79 Extrusion-based 3D printing is a widely used printing technology for hydrogel materials, which involves a structure-forming step based on the extrusion of ink and subsequent structure fixation.…”

Vat photopolymerization 3D printed microfluidic devices for organ-on-a-chip applications

“…188 Ding et al recently reviewed a wider array of light crosslinkable hydrogels that are compatible with DLP-SLA 3D printing systems. 189 While most of these resins are highly biocompatible, their ability to make the small, enclosed microfluidic channels and thin membranes common in OoC applications is less well understood and has not been as widely reported. Some of the smallest such features using a biomaterial based resin are those of Grigoryan et al, which demonstrated 150 μm thick membrane-like fin elements used in their perfusable 3D static mixer and 200 μm channels as part of their distal lung subunit.…”

“…188 Ding et al recently reviewed a wider array of light crosslinkable hydrogels that are compatible with DLP–SLA 3D printing systems. 189…”

Comprehensive performance of a low-cost spring-assisted mechanism for digital light processing

“…For example, SLA uses a laser, and digital light processing (DLP) uses a projector. DLP can be further divided according to the modeling direction of the build plate: constrained surface (i.e., bottom-up) [5] and free surface (i.e., top-down) [6]. Free-surface DLP covers the build plate with the photosensitive liquid resin for curing and molding, which are then stacked step by step in layers using a lifting platform.…”