Biography:Liang Ma, Associate Professor, School of Mechanical Engineering, Zhejiang University. Dr. Ma received a double bachelor degree in both Materials Science & Engineering and Bioinformatics in 2005 with Zhejiang University and doctor's degree in Mechanical Engineering Department of University of Washington at Seattle in 2012. He joined the team of Chinese academician of Engineering Prof. Huayong Yang at School of Mechanical Engineering, Zhejiang University in 2016 to carry out research on 3D bioprinting, including the development of high-precision multi-material 3D bioprinting system and its biomedical applications, especially in liver and tumor in vitro models for drug screening and microfluidic based bioprinting. He has published more than 40 high-impact SCI papers such as Biomaterials, Biofabrication, Small Methods, Engineering, Advanced Healthcare Materials. He now serves as the deputy director of the editorial office of SCI journal Bio-Design and Manufacturing.
The combination of microfluidic system and micro-extrusion based 3D bioprinting give us a new way to address the existing problems. Such a breakthrough technology, supply a bright prospect for constructing in vitro tissue models. They enable i) a precise manipulate the volume of bioink for a high resolution, ii) extrusion of multiple material from same nozzle, iii) possible to print graded scaffold with multiple material, iv) to print multilayer hollow tissue, v) the utilization of material with low printability but good biomimicry.
Microfluidic bioprinting has been applied extensively to construct in vitro biomimetic tissue model. Coaxial nozzle is employed to develop vascularized tissue, tubular urological tissues and other tubular tissue, supply a new approach for in vitro tissue vascularization. The use of microfluidic system could control the accuracy position of cells and arrange fibroblasts in alginate fiber, to obtain a co-culture model, thus receiving a high cell viability organoid tissue. The microfluidic system with two or more inlet and snake-like channel are used to fabric alginate microfiber with homogenous distribution cells, or print multi-material with concentration gradient thus can be utilized for generating heterogeneous organs/tissues.In order to create gradient tissue such as the liver acinus and brain microenvironment. A micro-extrusion based micromixer was developed. With this method, we have constructed a model to realize the concentration gradient characteristics of hepatic acinus in vitro. Suitable biological hydrogel materials were selected and the microfluidic mixer was designed and optimized to achieve the continuous concentration gradient variations of the hydrogel. Through this study, we used hydrogel to successfully reproduce the concentration and diffusion functions of hepatic acinus in vitro, which provided an effective platform for further study of drug-liver interaction.