3D bioprinting for cell culture and tissue fabrication

Bio-Design and Manufacturing (2018) 1:45–61 https://doi.org/10.1007/s42242-018-0006-1 REVIEW 3D bioprinting for cell culture and tissue fabrication Honglei Jian1 · Meiyue Wang1 · Shengtao Wang1 · Anhe Wang1 · Shuo Bai1 Received: 9 January 2018 / Accepted: 27 January 2018 / Published online: 26 February 2018 © Zhejiang University Press 2018 Abstract Three-dimensional (3D) bioprinting is a computer-assisted technology which precisely controls spatial position of biomaterials, growth factors and living cells, offering unprecedented possibility to bridge the gap between structurally mimic tissue constructs and functional tissues or organoids. We briefly focus on diverse bioinks used in the recent progresses of biofabrication and 3D bioprinting of various tissue architectures including blood vessel, bone, cartilage, skin, heart, liver and nerve systems. This paper provides readers a guideline with the conjunction between bioinks and the targeted tissue or organ types in structuration and final functionalization of these tissue analogues. The challenges and perspectives in 3D bioprinting field are also illustrated. Keywords 3D bioprinting · Bioink · Cell culture · Tissue fabrication · Organoid Introduction Three-dimensional (3D) bioprinting, a computer-assisted technology, is able to precisely control spatial position of biomaterials, growth factors and living cells with an ultimate goal of creating functional tissues and organs [1,2]. 3D bioprinting is becoming more and more popular in tissue fabrication because of its capacity of using customized structures and autologous cells to directly produce complex and biomimetic tissue architectures [3,4]. During printing process, the biomaterials made for living cells that behave much like a liquid allowing to “print” into a desired shape, are called bioinks. 3D bioprinting technology offers unprecedented possibility to bridge the gap between structurally mimic tissue constructs and functional tissues or organoids [5–7]. According to the employed printing mechanisms, the bioprinting techniques for tissue fabrication are classified into three main types: extrusion-, droplet- and laser- based bioprinting process [8]. In general, extrusion-based bioprinting, perhaps the most widespread method for fabrication, Honglei Jian and Meiyue Wang have contributed equally to this work. B Shuo Bai 1 State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China depends on mechanical-, pneumatic- or solenoid-driven micro-extrusion to create continuous strands of bioink [9]. In droplet-based bioprinting, various kinds of energy sources covering thermal, piezoelectric, electrostatic, hydrodynamic, acoustic and microvalve are employed to generate droplets of bioink [10]. In the case of laser-based bioprinting, laser energy is utilized for high-precision deposition of bioinks [11]. These bioprinting processes have their respective printing features and requirements of suitable inks [12], which are summarized in Table 1. With regard to the fabrication of a desired tissue or organoid, the consideration about the suitable bioink features is far beyond the choice of a suitable bioprinting process. When a biomaterial is printed onto the substrate (i.e., the receiving surface), it needs to undergo a fast phase transition to preserve the shape and resolution, and thereafter maintain cell viability and proliferation during post-printing incubation [13], which is one of the most important features distinguishing injectable and printable hydrogel material [14,15]. The structural and functional diversity of tissue fabrication leads to a wide development of bioink. The major bioink material used in tissue biofabrication and 3D bioprinting is hydrogel matrix and usually nature-derived. It is because of that high-water content of hydrogel, up to 1000 times of their original weight in aqueous media [16], enables well penetration of oxygen, nutrients, growth factors and other water-soluble components, thereby making them very suitable for tissue or organoid fabrication [17]. 123 46 Bio-Design and Manufacturing (2018) 1:45–61 Table 1 Types and features of bioprinting techniques [8,12] Types of bioprinting Extrusion-based Requirements of bioink Viscosity < 6 × 107 mPa s, shear Viscosity < 15 mPa s, rheopectic Viscosity < 300 mPa s, viscoelasticity, thinning, thixotropic behavior, low behavior, nonfibrous nature, intermediate adhesion, low surface surface tension and adhesion, rapid medium surface tension, rapid tension, absorption of laser kinetic gelation, shape retention gelation energy, rapid gelation Requirements of substrate Wettability, high surface roughness Wettability, high surface roughness, induces viscous forces Wettability, high surface roughness, induces viscous forces Printing speed Slow Medium Fast Cell density High, spheroids < 106 cells/mL < 108 cells/mL Post-printing cell viability ∼ 80% > 85% 95% Cost Medium Low High Recent advances in bioink materials for constructing 3D cell environments have greatly promoted the development of tissue engineering. The printability of the biomaterials heavily relies on their inherent mechanical properties such as rheological properties [18–20], bioactive moieties [21,22] and degradation behavior. For instance, the rheological properties of a bioink have a direct influence on printability, compatibility, shear stress yielded by cell encapsulation, as well as structural integrity and resolution of 3D printed construct [23]. The gelation process of a bioink matrix has a crucial role in both the resolution and cell viability [24]. Furthermore, the mechanical properties and degradation behavior not only affect cell growth, proliferation and differentiation, but also long-term biocompatibility in the fabricated tissues [25–28]. Although 3D bioprinting has made some attractive progress in tissue fabrication, this technique has not yet been used to make a lab-to-clinic translation. This paper reviews the recent progresses in 3D bioprinting from the perspective of tissue and organoid biofabrication. When planning for bioprinting, one should first consider the microenvironment characteristics and cell types of the targeted tissue or organ, and thereafter choose suitable bioink materials and a rational printing strategy. Therefore, we briefly focus on the diverse bioinks used for biofabrication of tissues and organoid including blood vessel, bone, cartilage, skin, heart, liver and nerve. The paper provides readers a guideline with the conjunction between bioinks and the targeted tissue or organ types in structuration and final functionalization of these tissue analogues. The challenges and perspectives in 3D bioprinting field are also illustrated. Bioprinting of blood vessel The vascular networks exist in almost all organs of the human body, playing crucial roles in nutrient transport and 123 Droplet-based Las (...truncated)