2023 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2023): Applications: Biomedical
Program Organizers: Joseph Beaman, University of Texas at Austin
Wednesday 1:10 PM
August 16, 2023
Room: 408
Location: Hilton Austin
Session Chair: Fay Claybrook, Loughborough University; Mazher Mohammed, Loughborough University
1:10 PM
Additive Manufacturing of Person Specific Diabetic Foot Insoles with Adjustable Cushioning Properties using TPMS Lattice Structures: Fay Claybrook1; Mazher Mohammed1; Darren Southee1; 1Loughborough University
Complications associated with diabetes are numerous, including foot problems which can lead to amputations. Nerves loose sensation and raised blood sugar can damage the circulation, making healing slower. Current management involves the use of foam diabetic foot insoles (DFI) to provide cushioning, however load bearing capacity is limited, and designs often do not provide a comfortable or efficacious fit. This study aspires to resolve problems using digital fabrication workflows. We explore the potential of 3D scanning of anatomical data, parametric modelling, and additive manufacturing to create a patient specific DFI. We demonstrate that patient scanning data provides means to create a custom fitting insole template, improving overall fit. We also demonstrate use of triply periodic minimal surface (TPMS) structures, fabricated in Thermoplastic Polyurethane, as cushioning structures, whereby unique lattice designs allow regionally tailored mechanical loading properties of the insole concept. The final insole realises a superior alternative to tradition DFI.
1:30 PM
Assembly-free Hybrid Printing of Microfluidic Devices for Biosensing: Yipu Du1; Julius Reitemeier2; Qiang Jiang1; Yuxuan Liao1; Paul Bohn1; Yanliang Zhang1; 1University of Notre Dame; 2Univerisity of Notre Dame
The advent of 3D printing has facilitated the creation of microfluidic devices that are accessible and cost-effective. However, producing complex microfluidic devices with integrated structural and functional electronic components remains a challenge, often requiring complicated post-fabrication assembly steps. Here, we introduce a hybrid printing method that streamlines the production of multicomponent microfluidic devices with embedded channels and electrodes at microscale resolution without post-fabrication assembly. Using this approach, we successfully fabricated microfluidic sensors comprising microscale interdigitated electrode arrays for the amperometric sensing of lactate in sweat. The amperometric sensors demonstrated a sensitive response with a limit of detection of 442 nM and a linear dynamic range of 1 - 10 mM, which are performance characteristics relevant to physiological levels of lactate in sweat. The proposed hybrid printing method is straightforward, versatile, and cost-effective, making it suitable for a wide range of point-of-use monitoring and sensing applications.
1:50 PM
Evaluation of the Performance of 3D Printed Cutting Guides for Canine Caudal Maxillectomy: Aidan Chambers1; Marine Traverson1; Satyanarayana Konala1; Shelby Neal1; Ola Harrysson1; 1North Carolina State University
Canine caudal maxillectomy is a surgical procedure commonly performed on dogs to remove cancerous tumors in the caudal portion of the maxilla. However, the procedure is associated with significant risks such as major hemorrhage and high recurrence rates due to incomplete resection of the cancerous bone. To address these issues, cutting guides were designed and printed in resin using SLA and surgery was performed by three groups: an experienced surgeon (SG), a novice surgical resident (NG), and a surgeon performing a freehand procedure (SF). Each group performed five cuts on cadaveric heads, and the accuracy of the cuts was evaluated. The highest absolute mean linear deviation recorded in SF, NG, and SG groups were 5.46±4.28 mm, 3.19±1.64 mm, and 1.98±0.81 mm, respectively, and occurred at the orbit osteotomy. However, the procedure duration was found to be significantly longer for guided surgery (p < 0.001).
2:10 PM
Fabrication of Thick Vascularized Tissues using Sacrificial Ink-assisted Embedded 3D Bioprinting: Bing Ren1; Yong Huang1; 1University of Florida
Engineering three-dimensional (3D) in vitro vascularized tissue models remains a great challenge. Herein, a strategy integrating the sacrificial ink-assisted embedded bioprinting with cellular self-assembly is proposed to create thick vascularized tissues with macro- and micro-vessels. Perfusable channel structures are fabricated by embeddedly printing a sacrificial ink in an endothelial cell-laden and gelatin microgel-based yield-stress composite matrix. The sacrificial ink is removed to form channels as engineered macro-vessels after printing is completed and the matrix is crosslinked; micro-vessels are formed by self-assembly of encapsulated endothelial cells in the matrix. This embedded bioprinting approach has been implemented to print a composite matrix-based human alveolar model with vascularized air and fluid channels that are seeded with alveolar epithelial cells and endothelial cells, respectively, as well as composite matrix-based thick structured meat with macro-vessels seeded with endothelial cells and micro-vessels assembled by endothelial cells.
2:30 PM
Improving Food 3D Printing Through Texture Modification of Designed Food Inks: Stefania Chirico-Scheele1; Gabriel Goncalves1; William Clearman1; Martin Binks1; Paul Egan1; 1Texas Tech University
Three-dimensional food printing is well-suited for producing foods with desired textural properties for consumers. However, it is difficult to fabricate desirable foods that print accurately and are nutritious. Here, we conduct texture measurements of designed food inks to determine printability and consumer appeal. Food ingredients include soy protein powder, strawberry powder, and cream cheese powder. The texture of food inks, specifically the firmness, was measured by compression testing, and resulted in firmness measurements of 206 g, 99 g, and 53 g, respectively. Strawberry and soy did not print accurately, but when combined homogenously in a 50 % / 50 % mixture, printing accuracy was improved while firmness reduced to 40 g. Consumer assessment experiments revealed that participants rated foods printed with the highest fidelity as the most desirable, which motivates the design of food inks to improve appeal through texture and printability modulation to support future delivery of personalized foods.
2:50 PM Break
3:20 PM
Materials Screening Methodology for Additive Manufacturing in Bioreactor Technology: Johann Schorzmann1; Hannes Gerstl1; Zhixin Tan1; Lys Sprenger1; Hsuan-Heng Lu2; Sarah Taumann1; Marco Wimmer1; Sahar Salehi-Müller1; Aldo R. Boccaccini2; Frank Döpper1; 1University of Bayreuth; 2Institute of Biomaterials, University of Erlangen-Nuremberg
Biofabrication is used to fabricate complex organs and mimic tissue structures from bio-inks (biopolymers enriched with living cells) using additive manufacturing (AM). Electroactive cells such as skeletal muscle function via electrical signals and therefore, their optimum in vitro functionality requires electrical stimulations. AM can be used to precisely fabricate a bioreactor for a dynamic culture of cells and bioengineered tissues with selective electrical conductivity and electrical stimulation of the cells. In this study, we focused on a material selection methodology for AM of bioreactors based on Reuter. Fulfilling all material requirements, biocompatibility, chemical stability, electrical conductivity, and sterilization, are the main criteria in the fabrication of bioreactor. But there is no standardized procedure for selecting materials in AM.Our study comprises four phases which deductively narrowed down the material selection (Phase I-IV: determination of material requirements; pre-selection of suitable materials; fine selection and assessment; evaluation/ validation of material properties).
3:40 PM
A Study of Additively Manufactured Ti-6Al-4V ELI Surface Roughness Coupons with Differing Processing Parameters: Lucas Becker1; 1AddUp Inc.
Additive manufacturing, particularly laser powder bed fusion (LPBF), allows for increased complexity and robustness of medical parts and implants. Bio-compatible materials like Ti-6Al-4V ELI play a key role in the creation of these and thus need to be studied for their as-printed and post-processed physical properties like surface roughness for adoption in real-life applications. In this study, surface roughness was investigated with respect to printing process parameters using a roller recoating system. In addition, surface roughness was analyzed across the build plate under different post-build thermal conditions. Some of the samples were post-processed to see how effective bead blasting is at improving the surface finish. This study implies that printing parameters and post processing conditions can be utilized to alter the surface finish of the LPBF processed parts.