Three‐dimensional (3D) printing, also called additive manufacturing (AM) or rapid prototyping (RP), is a layer by layer manufacturing method and now has been widely used in many areas such as organ printing, aerospace and industrial design. Now 3D printed microfluidics attract more and more interests for its rapid printing in the lab. In this review, we focused on the advances of 3D printed microfluidic chips especially the use in the chemistry and biology (vascularization and organs on chips). Based on the brief review of different 3D printing methods, we discussed how to choose the suitable 3D printing methods to print the desired microfluidics. We predict that microfluidics will be evolved from 2D chips to 3D cubes, printed hydrogel‐based microfluidics will be reported and widely used, sensors & actuators could be integrated in the microfluidics during printing, and rapid assembling chips with printed microfluidic modules will be popular in the near future.

In this study, 3D hydrogel-based vascular structures with multilevel fluidic channels (macro-channel for mechanical stimulation and microchannel for nutrient delivery and chemical stimulation) were fabricated by extrusion-based three-dimensional (3D) bioprinting, which could be integrated into organ-on-chip devices that would better simulate the microenvironment of blood vessels. In this approach, partially cross-linked hollow alginate filaments loading fibroblasts and smooth muscle cells were extruded through a coaxial nozzle and then printed along a rotated rod template, and endothelial cells were seeded into the inner wall. Because of the fusion of adjacent hollow filaments, two-level fluidic channels, including a macro-channel in the middle formed from the cylindrical template and a microchannel around the wall resulted from the hollow filaments were formed. By this method, different shapes of vessellike structures of millimeter diameter were printed. The structures printed using 4% alginate exhibited ultimate strength of 0.184 MPa, and L929 mouse fibroblasts encapsulated in the structures showed over 90% survival within 1 week. As a proof of concept, an envisioned load system of both mechanical and chemical stimulation was demonstrated. In addition, a vascular circulation flow system, a cerebral artery surgery simulator, and a cell coculture model were fabricated to demonstrate potential tissue engineering applications of these printed structures.

Hydrogel microspheroids are widely used in tissue engineering, such as injection therapy and 3D cell culture, and among which, heterogeneous microspheroids are drawing much attention as a promising tool to carry multiple cell types in separated phases. However, it is still a big challenge to fabricate heterogeneous microspheroids that can reconstruct built-up tissues' microarchitecture with excellent resolution and spatial organization in limited sizes. Here, a novel airflow-assisted 3D bioprinting method is reported, which can print versatile spiral microarchitectures inside the microspheroids, permitting one-step bioprinting of fascinating hydrogel structures, such as the spherical helix, rose, and saddle. A microfluidic nozzle is developed to improve the capability of intricate cell encapsulation with heterotypic contact. Complex structures, such as a rose, Tai chi pattern, and single cell line can be easily printed in spheroids. The theoretical model during printing is established and process parameters are systematically investigated. As a demonstration, a human multicellular organoid of spirally vascularized ossification is reconstructed with this method, which shows that it is a powerful tool to build mini tissues on microspheroids.

Here, we constructs a whole vascular system, from arteries and capillaries to veins with a high resolution 3D printing. A bulk breast tumor tissue with a functional vascular network was built. The interaction between tumors and vessels is investigated.

No abstract

No abstract

No abstract

No abstract