Advances in Biomaterials for 3D Printing of Scaffolds and Tissues: Session II
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Biomaterials Committee
Program Organizers: Changxue Xu, Texas Tech University; Jun Yin, Zhejiang University; Zhengyi Zhang, Huazhong University of Science and Technology; Yifei Jin, University of Nevada Reno; Heqi Xu, Texas Tech University
Wednesday 2:00 PM
March 22, 2023
Room: Sapphire 410A
Location: Hilton
Session Chair: Heqi Xu, Zhejiang University
2:00 PM
Investigation of Cell Sedimentation and Cell Aggregation during 3D Bioprinting: Md Shahriar1; Heqi Xu1; Jiachen Liu1; Changxue Xu1; Dulce Martinez Salazar1; 1Texas Tech University
Bioink, as an essential element for 3D bioprinting, is composed of biological materials and living cells. When the buoyant force is not sufficient to balance the gravitational force, the suspended cells are driven by dominant gravitational force to sediment and finally accumulate at the bottom of the bioink reservoir. With cell accumulation at the bottom of the bioink reservoir, the interaction and aggregation of cells are facilitated. Due to the cell sedimentation and aggregation, the uniformity of the cell distribution within the bioink reservoir is reduced and the printing performance is significantly affected. This study investigates the cell sedimentation velocities of individual cells, small cell aggregates, and large cell aggregates at different printing time. In addition, the percentages of cells forming different types of cell aggregates and the cell concentrations in different regions of the bioink reservoir are characterized at different printing time, respectively.
2:20 PM
Processing and Properties of 3D Printed Bioabsorbable Polymer-Metal Composites (PLDL/Mg and PLDL/Zn) for Orthopaedic Applications: Cillian Thompson1; Guillermo Domínguez1; Jimena de la Vega1; Cristina Pascual-González2; Monica Echeverry-Rendón1; Carlos González3; Javier Llorca3; 1IMDEA Materials Institute; 2Rey Juan Carlos University; 3IMDEA Materials Institute & Technical University of Madrid
Filaments of 2.85 mm in diameter of poly-lactic acid reinforced with different weight fractions of µm-sized Mg or Zn particles were obtained by a double extrusion in method in which standard extrusion is followed by a precision extrusion in a filament-makermachine. The filaments had constant diameter, negligible porosity and a homogeneous reinforcement distribution. They were used to manufacture porous scaffolds by fused-filament fabrication. The mechanical properties, degradation rate and cytocompatibility of the 3D printed materials and scaffolds were measured following ISO standards. The influence of the metallic particles on the deformation and fracture mechanisms, the degradation processes in simulated body fluid and the material/cell interactions were analyzed. It was found that all the materials were suitable for orthopaedic applications and that the addition of metallic particles can be used to tailor the degration rate. In addition, it was possible to manufacture porous scaffolds with excellent dimensional accuracy by fused-filament fabrication.
2:40 PM
Investigation of Cellular Attachment and Morphology on a 3D-printed Curved Micropillar Substrate: Eduardo Pena1; Md Shahriar1; Changxue Xu1; 1Texas Tech University
Cells in the complex extracellular matrix are arranged in a three-dimensional configuration. Curving and folding of tissues are common architectural phenotypes that provide the unique advantage of enhanced surface area, cell viability, and cellular functionality. Most of the cell culture and tissue engineering studies involve 2D planar surfaces which do not represent the realistic complexity of the cellular microenvironment. Therefore, it is of great importance to develop 3D architectures including curvature featuring biocompatible materials that provide necessary physio-mechanical and chemical properties for cellular proliferation and differentiation. Recently, the two-photon polymerization technique has gained more and more attention as a high-precision 3D printing technology for various biomedical and tissue engineering applications. In this study, flat and curved micropillar substrates have been fabricated using the two-photon polymerization technique. The main objective of this research is to investigate the effect of the substrate shape (curved vs flat) on the cellular attachment and morphology.
3:00 PM
The Influence of Printing Orientation on the Mechanical Properties of 3D Printed Parts by Stereolithography (SLA) Process: Michael Melly1; Alyssa Napora1; Olivia Lowe1; Chao Gao2; Fariborz Tavangarian1; 1Pennsylvania State University Harrisburg; 2Norwegian University of Science and Technology
Additive manufacturing is one of the most promising techniques to manufacture various parts with complex geometry. It has been used in different industries to produce end user products. In 3D printing process, the part is made layer upon layer and the final geometry is formed. Without the post processing techniques, the obtained parts are anisotropic. Depends on the printing orientation, the mechanical properties can vary drastically from one printing orientation to another. In this study, we investigated the printing orientation and its effect on the mechanical properties of the part. The relation between the microstructure and mechanical properties and the involved mechanism has been investigated.
3:20 PM Cancelled
Improving Predictability of Additively Manufactured Ti-6Al-4V Lattices for Customised Orthopaedic Devices: Xue Cao1; 1University of Birmingham
Selective laser melting (SLM), as an additive manufacturing (AM) technology, enables manufacture of complex Ti-6Al-4V lattice structures that may promote osseointegration. However, due to rapid heating and cooling, the final quality of products significantly depends on the SLM process parameters, scanning strategies, build orientations and geometric features. Herein, the scanning strategy and process window were first optimised, by which lattices with extremely fine struts (150m) can be accurately fabricated (error below 0.1%). Surface roughness, 3-point bending, and in-vitro response of osteoblasts were assessed for individual lattice struts manufactured from 20 to 90 rotations using the optimised parameters (150W, 1125mm/s). The melt pool behaviour was also evaluated using an in-situ process monitoring system adding further understanding to SLM process predictability. Bringing these studies together a tool was developed to guide stakeholders in producing customised porous orthopaedic devices that enables key physiochemical properties to be controlled with the aim of maximising osseointegration.