دانلود رایگان ترجمه مقاله چاپ سه بعدی و چاپ های زیستی سه بعدی در اطفال (نشریه MDPI 2017)

چاپ سه بعدی و چاپ های زیستی سه بعدی در اطفال

3D Printing and 3D Bioprinting in Pediatrics

Abstract

Additive manufacturing, commonly referred to as 3D printing, is a technology that builds three-dimensional structures and components layer by layer. Bioprinting is the use of 3D printing technology to fabricate tissue constructs for regenerative medicine from cell-laden bio-inks. 3D printing and bioprinting have huge potential in revolutionizing the field of tissue engineering and regenerative medicine. This paper reviews the application of 3D printing and bioprinting in the field of pediatrics.

1 Introduction

3D printing or additive manufacturing (AM) is a process of fabricating three dimensional solid objects from a 3D model or digital file. Additive manufacturing consists of several techniques to build 3D objects layer by layer, which are grouped under seven categories by American Society for Testing and Materials (ASTM) Committee F42 on Additive Manufacturing Technologies, as shown in Table 1 [1]. The description of each process is also given in the table.

Bioprinting is defined as the use of 3D printing technology with materials that incorporate viable living cells, e.g., to produce tissue for reconstructive surgery [2]. Biopolymers or cell-laden hydrogels are arranged spatially in a 3D dimensional pattern and built layer by layer into a tissue or organ. The three main bioprinting techniques are laser-assisted bioprinting, inkjet bioprinting, and extrusion bioprinting [3,4], as shown in Figure 1. Laser-assisted bioprinting focuses laser pulses on to the donor slide, thus creating high pressure to propel droplets of cell-laden hydrogel on to the collector slide. Inkjet printing ejects droplets of biopolymer or cell-laden hydrogels through a nozzle by either thermal energy application (electrically heating to produce vapor bubbles that forces droplets to come out through the nozzle) or a piezoelectric actuator (actuation of piezoelectric crystals by applying electrical energy at high frequencies). Extrusion or robotic dispensing bioprinters extrude biopolymers or cell-laden hydrogels through the nozzle by applying air pressure (pneumatic) or mechanical systems (piston or screw). The pros and cons of these three types of bioprinting processes are given in Table 2. Though bioprinting is a potential technology for tissue engineering and regenerative medicine, there are many ethical, legal, and social concerns which are to be overcome before it can be successfully put into clinical use [4,5].

Material selection is key for the successful application of AM and bioprinting techniques. The choice of material depends on the intended application. For the fabrication of 3D organ models for surgical planning, the resolution of the to-be printed model determines the AM technique to be used and hence, the material. If one of the Vat Polymerization processes such as SLA were used, then the material would be a photopolymer. Here, the resolution required determines the process and the materials, as their intended use is for surgery planning and training. However, the selection of materials becomes a critical step when it comes to tissue or organ printing. For the bioprinting of soft tissues such as skin, natural polymer-based hydrogels such as collagen, gelatin, and chitosan are used. On the other hand, for hard tissues such as bone, materials with better mechanical properties are preferred to meet the functional tissue requirement. Hence, synthetic polymers such as Polycaprolactone (PCL) and naturally occurring minerals such as hydroxyapatite (HA) are used for bone tissue engineering [6–8].