Chapter 3
3D Printing of Functionally Graded Films by Controlling
Process Parameters
Alessandra Bonfanti, Loris Domenicale, and Atul Bhaskar
Abstract
Scaffolds are often used in bioengineering to replace damaged tissues. They promote cell ingrowth and
provide mechanical support until cells regenerate. Such scaffolds are often made using the additive
manufacturing process, given its ability to create complex shapes, affordability, and the potential for
patient-specific solutions. The success of the implant is closely related to the match of the scaffold
mechanical properties to those of the host tissue. Many biological tissues show properties that vary in
space. Therefore, the aim is to manufacture materials with variable properties, commonly referred to as
functionally graded materials. Here we present a novel technique used to manufacture porous films with
functionally graded properties using 3D printers. Such an approach exploits the control of a process
parameter, without any hardware modification. The mechanical properties of the manufactured films
have been experimentally tested and analytically characterized.
Key words Additive manufacturing, Functionally graded material, Graded films, G-code, Process
parameter, Extrusion rate
1 Introduction
After decades of development of medical implants made of dense
materials, porous scaffolds have brought excitement to the area as
they afford improved mechanical performance and they promote
cell ingrowth [1, 2, 3]. Scaffolds are used in tissue engineering to
mimic the extracellular matrix of the body allowing regeneration of
damaged or diseased tissues [4–6]. The success of cell culture
depends on the internal architecture (e.g., pore size) of the scaffolds [7–9]. In case of the regeneration of multiple tissues (e.g.,
bone, cartilage), different cell types are necessary. Each of them
operates under different in vivo conditions, and, therefore, different scaffold geometries and porosity are required to promote cell
growth [10, 11]. Such scaffolds with spatially varying architecture
are commonly referred to as functionally graded scaffolds
[12]. While reproducing the spatial gradation of properties
Alberto Rainer and Lorenzo Moroni (eds.), Computer-Aided Tissue Engineering: Methods and Protocols,
Methods in Molecular Biology, vol. 2147, https://doi.org/10.1007/978-1-0716-0611-7_3,
© Springer Science+Business Media, LLC, part of Springer Nature 2021
31
3D Printing of Functionally Graded Films by Controlling
Process Parameters
Alessandra Bonfanti, Loris Domenicale, and Atul Bhaskar
Abstract
Scaffolds are often used in bioengineering to replace damaged tissues. They promote cell ingrowth and
provide mechanical support until cells regenerate. Such scaffolds are often made using the additive
manufacturing process, given its ability to create complex shapes, affordability, and the potential for
patient-specific solutions. The success of the implant is closely related to the match of the scaffold
mechanical properties to those of the host tissue. Many biological tissues show properties that vary in
space. Therefore, the aim is to manufacture materials with variable properties, commonly referred to as
functionally graded materials. Here we present a novel technique used to manufacture porous films with
functionally graded properties using 3D printers. Such an approach exploits the control of a process
parameter, without any hardware modification. The mechanical properties of the manufactured films
have been experimentally tested and analytically characterized.
Key words Additive manufacturing, Functionally graded material, Graded films, G-code, Process
parameter, Extrusion rate
1 Introduction
After decades of development of medical implants made of dense
materials, porous scaffolds have brought excitement to the area as
they afford improved mechanical performance and they promote
cell ingrowth [1, 2, 3]. Scaffolds are used in tissue engineering to
mimic the extracellular matrix of the body allowing regeneration of
damaged or diseased tissues [4–6]. The success of cell culture
depends on the internal architecture (e.g., pore size) of the scaffolds [7–9]. In case of the regeneration of multiple tissues (e.g.,
bone, cartilage), different cell types are necessary. Each of them
operates under different in vivo conditions, and, therefore, different scaffold geometries and porosity are required to promote cell
growth [10, 11]. Such scaffolds with spatially varying architecture
are commonly referred to as functionally graded scaffolds
[12]. While reproducing the spatial gradation of properties
Alberto Rainer and Lorenzo Moroni (eds.), Computer-Aided Tissue Engineering: Methods and Protocols,
Methods in Molecular Biology, vol. 2147, https://doi.org/10.1007/978-1-0716-0611-7_3,
© Springer Science+Business Media, LLC, part of Springer Nature 2021
31