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The technology of arranging particles by ultrasound has matured. In recent years, this technology has been used as a basis for arranging particles in a photocurable resin for stereolithography (SL). In order to process the resin doped with particles to obtain a variety of particle arrangement patterns, most of the previous work chose to use different polygonal containers to obtain single-layer fiber angles. In this adjustment mode, the selectivity of the fiber angle is very poor, usually 45°, 90° and other common angles. In this work, we designed and manufactured a new ultrasound-assisted 3D printing platform that can flexibly adjust the thickness of the sandwich and the rotation angle of the sandwich. We will introduce the basic working principle and matching usage of the device, and show some basic print samples.

Extrusion-based printing technology has a promising development in the field of tissue engineering scaffold. Researchers package cells/particles in biomaterials and then extrude them through a nozzle and solidify to get a scaffold. This method can achieve uniform distribution of cells/particles in biomaterials or the addition of particles in biomaterials to enhance the mechanical properties of the scaffold. Sodium alginate is a kind of polysaccharide biomaterial which has a wide range of applications in the field of bioprinting. However, the diameter of the nozzle determines the accuracy of the cells/particles position in the alginate scaffold. A method of ultrasonic-assisted 3D bioprinting a composite of alginate and particles is proposed. The acoustic pressure can concentrate cells/particles to the center of the nozzle, which can achieve a more precise positioning than the diameter of the nozzle, and facilitate the purpose of depositing specific cells/particles to the determined location of the biomaterial.

Extrusion-based bioprinting is one of the most common biomanufacturing methods. The bioink composed of biomaterials and living cells is extruded into cylindrical filaments. The filaments are deposited on the substrate and stacked layer by layer to form a three-dimensional structure. During the extrusion process, the ink tends to accumulate at the nozzle, which clogs the nozzle and increases extrusion pressure, resulting in the decrease of cell survival rate. Here, we propose a method of using ultrasound to manipulate cells to assist the bioprinting process, which can alleviate nozzle clogging. The ceramic piezoelectric plate(PZT) is used to drive the nozzle to generate structural resonance, and the ultrasonic standing wave generated by the vibration make the cells/particles in the ink gather at the center of the nozzle, thereby reducing the risk of clogging of the nozzle. In this paper, we first analyze the mechanism of the standing wave generated in the cylindrical elastic nozzle and drive the cells to move under the PZT drive, and then use the finite element software to simulate the standing wave drive process. The results show that this method can be solved by a simple and low-cost device. The results indicate that this method has the possibility of using simple and low-cost equipment to solve the problem of nozzle clogging in bioprinting.