scholarly journals Utilizing direct-initiation of thiols for photoinitiator-free stereolithographic 3D printing of mechanically stable scaffolds

2021 ◽  
Vol 7 (2) ◽  
pp. 847-850
Author(s):  
Klaus Kreuels ◽  
David Bosma ◽  
Nadine Nottrodt ◽  
Arnold Gillner
Keyword(s):  
Computer Aided Design ◽  
Biomedical Applications ◽  
Bulk Material ◽  
3D Cell Culture ◽  
Freeform Fabrication ◽  
Direct Initiation ◽  
Custom Made ◽  
Unit Cells ◽  
3D Printed ◽  
Living Tissues

Abstract The automated production of artificial biological structures for biomedical applications continues to gather interest. Different fields of science are combined to find solutions for the arising multidimensional problems. Additive manufacturing in combination with material science provides one solution for the biological issues around 3D cell culture and construction of living tissues. Here, we present the photoinitiator-free stereolithographic fabrication of thiol-ene polymers with microarchitectures in the range of tens of microns for scaffolds up to the millimeter scale. Scaffolds composed of cubic unit cells were designed using computer-aided design (CAD) and subsequently 3D printed with a custom-made laser stereolithography setup. The process parameters were determined step by step with increasing complexity and number of parameters. Gained insights were applied to the fabrication of 3D printed test specimens. The quality of the 3D printed parts was evaluated by measuring the porosity and optical microscopy images. Furthermore, the mechanical properties of the scaffold structures were characterized using compression testing and compared with the bulk material revealing a lower capacity to bear load but higher flexibility. In this study, we demonstrate the advantages of combining the high-precision, freeform fabrication of stereolithography with a biocompatible material for the fabrication of complex microarchitectures for biomedical applications

scholarly journals Custom-made artificial eyes using 3D printing for dogs: A preliminary study

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242274
Author(s):  
So-Young Park ◽  
Jeong-Hee An ◽  
Hyun Kwon ◽  
Seo-Young Choi ◽  
Ka-Young Lim ◽  
...  
Keyword(s):  
3D Printing ◽  
Computer Aided Design ◽  
Companion Animals ◽  
Manufacturing Cost ◽  
Artificial Eye ◽  
Custom Made ◽  
3D Printed ◽  
Preliminary Study ◽  
Ocular Implant

Various incurable eye diseases in companion animals often result in phthisis bulbi and eye removal surgery. Currently, the evisceration method using silicone balls is useful in animals; however, it is not available to those with impaired cornea or severe ocular atrophy. Moreover, ocular implant and prostheses are not widely used because of the diversity in animal size and eye shape, and high manufacturing cost. Here, we produced low-cost and customized artificial eyes, including implant and prosthesis, using computer-aided design and three-dimensional (3D) printing technique. For 3D modeling, the size of the artificial eyes was optimized using B-mode ultrasonography. The design was exported to STL files, and then printed using polycaprolactone (PCL) for prosthesis and mixture of PCL and hydroxyapatite (HA) for ocular implant. The 3D printed artificial eyes could be produced in less than one and half hour. The prosthesis was painted using oil colors and biocompatible resin. Two types of eye removal surgery, including evisceration and enucleation, were performed using two beagle dogs, as a preliminary study. After the surgery, the dogs were clinically evaluated for 6 months and then histopathological evaluation of the implant was done. Ocular implant was biocompatible and host tissue ingrowth was induced after in vivo application. The custom-made prosthesis was cosmetically excellent. Although long-term clinical follow-up might be required, the use of 3D printed-customized artificial eyes may be beneficial for animals that need personalized artificial eye surgery.

Design and Biological Simulation of 3D Printed Lattices for Biomedical Applications

2019 ◽  
Author(s):  
Paul F. Egan
Keyword(s):  
Sensitivity Analysis ◽  
Biomedical Applications ◽  
Volume Ratio ◽  
Computational Design ◽  
Tissue Growth ◽  
Analytical Relationship ◽  
Biological Growth ◽  
Trade Offs ◽  
Unit Cells ◽  
3D Printed

Abstract There is great potential for using 3D printed designs fabricated via additive manufacturing processes for diverse biomedical applications. 3D printing offers capabilities for customizing designs for each new fabrication that could leverage automated design processes for personalized patient care, but there are challenges in developing accurate and efficient assessment methods. Here, we conduct a sensitivity analysis for a biological growth simulation for evaluating 3D printed lattices for regenerating bone and then use these simulations to identify performance trends. Four design topologies were compared by generating varied unit cells. Biological growth was modeled in a voxel environment by simulating the advancement of a tissue front by calculating its local curvature. Designs were generated with properties suitable for bone tissue engineering, namely 50% porosity and microscale pores. The sensitivity analysis determined trade-offs between prediction consistency and computation time, suggesting calculating curvature within a radius of 7.5 voxels is sufficient for most cases. Topologies were compared in bulk with design variations. All topologies had similar tissue growth rates for a given surface-volume ratio, but with differing unit cell sizes. These findings inform future optimization for selecting unit cells based on volume requirements and other criteria, such as mechanical stiffness. A fitted analytical relationship predicted tissue growth rate based on a design’s surface-volume ratio, which enables design evaluation without computationally expensive simulations. Lattices were 3D printed with biocompatible materials as proof-of-concepts, demonstrating the feasibility of the approach for future computational design methods for personalized medicine.

scholarly journals Design Data and Finite Element Analysis of 3D Printed Poly(ε-Caprolactone)-Based Lattice Scaffolds: Influence of Type of Unit Cell, Porosity, and Nozzle Diameter on the Mechanical Behavior

Eng ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 9-23
Author(s):  
Riccardo Sala ◽  
Stefano Regondi ◽  
Raffaele Pugliese
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Computer Aided Design ◽  
Unit Cell ◽  
Critical Parameters ◽  
Lattice Structures ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Custom Made ◽  
3D Printed

Material extrusion additive manufacturing (MEAM) is an advanced manufacturing method that produces parts via layer-wise addition of material. The potential of MEAM to prototype lattice structures is remarkable, but restrictions imposed by manufacturing processes lead to practical limits on the form and dimension of structures that can be produced. For this reason, such structures are mainly manufactured by selective laser melting. Here, the capabilities of fused filament fabrication (FFF) to produce custom-made lattice structures are explored by combining the 3D printing process, including computer-aided design (CAD), with the finite element method (FEM). First, we generated four types of 3D CAD scaffold models with different geometries (reticular, triangular, hexagonal, and wavy microstructures) and tunable unit cell sizes (1–5 mm), and then, we printed them using two nozzle diameters (i.e., 0.4 and 0.8 mm) in order to assess the printability limitation. The mechanical behavior of the above-mentioned lattice scaffolds was studied using FEM, combining compressive modulus (linear and nonlinear) and shear modulus. Using this approach, it was possible to print functional 3D polymer lattice structures with some discrepancies between nozzle diameters, which allowed us to elucidate critical parameters of printing in order to obtain printed that lattices (1) fully comply with FFF guidelines, (2) are capable of bearing different compressive loads, (3) possess tunable porosity, and (3) overcome surface quality and accuracy issues. In addition, these findings allowed us to develop 3D printed wrist brace orthosis made up of lattice structures, minimally invasive (4 mm of thick), lightweight (<20 g), and breathable (porosity >80%), to be used for the rehabilitation of patients with neuromuscular disease, rheumatoid arthritis, and beyond. Altogether, our findings addressed multiple challenges associated with the development of polymeric lattice scaffolds with FFF, offering a new tool for designing specific devices with tunable mechanical behavior and porosity.

Bone tissue engineering in the greater omentum with computer-aided design/computer-aided manufacturing scaffolds is enhanced by a periosteum transplant

2020 ◽  
Author(s):  
Hendrik Naujokat ◽  
Klaas Loger ◽  
Juliane Schulz ◽  
Yahya Açil ◽  
Jörg Wiltfang
Keyword(s):  
Bone Formation ◽  
Bone Tissue ◽  
Computer Aided Design ◽  
Bone Tissue Regeneration ◽  
Histological Evaluation ◽  
Greater Omentum ◽  
Collagen Membrane ◽  
Computer Aided ◽  
3D Printed ◽  
The Impact

Aim: This study aimed to evaluate two different vascularized bone flap scaffolds and the impact of two barrier membranes for the reconstruction of critical-size bone defects. Materials & methods: 3D-printed scaffolds of biodegradable calcium phosphate and bioinert titanium were loaded with rhBMP-2 bone marrow aspirate, wrapped by a collagen membrane or a periosteum transplant and implanted into the greater omentum of miniature pigs. Results: Histological evaluation demonstrated significant bone formation within the first 8 weeks in both scaffolds. The periosteum transplant led to enhanced bone formation and a homogenous distribution in the scaffolds. The omentum tissue grew out a robust vascular supply. Conclusion: Endocultivation using 3D-printed scaffolds in the greater omentum is a very promising approach in defect-specific bone tissue regeneration.

scholarly journals 3D Printed Clamps for In Vitro Tensile Tests of Human Gracilis and the Superficial Third of Quadriceps Tendons

2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Biomechanical Properties ◽  
Testing Procedure ◽  
Laboratory Equipment ◽  
Fused Deposition ◽  
Custom Made ◽  
3D Printed

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.

scholarly journals Recurrent contracted sockets treated with personalized, three-dimensionally printed conformers and buccal grafts

2021 ◽  
pp. 112067212110000
Author(s):  
Annabel LW Groot ◽  
Jelmer S Remmers ◽  
Roel JHM Kloos ◽  
Peerooz Saeed ◽  
Dyonne T Hartong
Keyword(s):  
Three Dimensional ◽  
Case Series ◽  
Secondary Outcome ◽  
Retrospective Case ◽  
Upper Eyelid ◽  
Ocular Prosthesis ◽  
Buccal Mucosal Graft ◽  
Custom Made ◽  
3D Printed

Purpose: Recurrent contracted sockets are complex situations where previous surgeries have failed, disabling the wear of an ocular prosthesis. A combined method of surgery and long-term fixation using custom-made, three-dimensional (3D) printed conformers is evaluated. Methods: Retrospective case series of nine patients with recurrent excessive socket contraction and inability to wear a prosthesis, caused by chemical burns ( n = 3), fireworks ( n = 3), trauma ( n = 2) and enucleation and radiotherapy at childhood due to optic nerve glioma ( n = 1) with three average previous socket surgeries (range 2–6). Treatment consisted of a buccal mucosal graft and personalized 3D-printed conformer designed to be fixated to the periosteum and tarsal plates for minimal 2 months. Primary outcome was the retention of an ocular prosthesis. Secondary outcome was the need for additional surgeries. Results: Outcomes were measured at final follow-up between 7 and 36 months postoperatively (mean 20 months). Eight cases were able to wear an ocular prosthesis after 2 months. Three cases initially treated for only the upper or only the lower fornix needed subsequent surgery for the opposite fornix for functional reasons. Two cases had later surgery for cosmetic improvement of upper eyelid position. Despite pre-existing lid abnormalities (scar, entropion, lash deficiency), cosmetic outcome was judged highly acceptable in six cases because of symmetric contour and volume, and reasonably acceptable in the remaining two. Conclusions: Buccal mucosal transplant fixated with a personalized 3D-designed conformer enables retention of a well-fitted ocular prosthesis in previously failed socket surgeries. Initial treatment of both upper and lower fornices is recommended to avoid subsequent surgeries for functional reasons.

scholarly journals An Innovative and Cost-Advantage CAD Solution for Cubitus Varus Surgical Planning in Children

2021 ◽  
Vol 11 (9) ◽  
pp. 4057
Author(s):  
Leonardo Frizziero ◽  
Gian Maria Santi ◽  
Christian Leon-Cardenas ◽  
Giampiero Donnici ◽  
Alfredo Liverani ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Low Cost ◽  
Cost Effective ◽  
Varus Deformity ◽  
Patient Specific ◽  
Cubitus Varus ◽  
Surgical Guide ◽  
Traditional Procedure ◽  
Custom Made ◽  
Patient Specific Instruments

The study of CAD (computer aided design) modeling, design and manufacturing techniques has undergone a rapid growth over the past decades. In medicine, this development mainly concerned the dental and maxillofacial sectors. Significant progress has also been made in orthopedics with pre-operative CAD simulations, printing of bone models and production of patient-specific instruments. However, the traditional procedure that formulates the surgical plan based exclusively on two-dimensional images and interventions performed without the aid of specific instruments for the patient and is currently the most used surgical technique. The production of custom-made tools for the patient, in fact, is often expensive and its use is limited to a few hospitals. The purpose of this study is to show an innovative and cost-effective procedure aimed at prototyping a custom-made surgical guide for address the cubitus varus deformity on a pediatric patient. The cutting guides were obtained through an additive manufacturing process that starts from the 3D digital model of the patient’s bone and allows to design specific models using Creo Parametric. The result is a tool that adheres perfectly to the patient’s bone and guides the surgeon during the osteotomy procedure. The low cost of the methodology described makes it worth noticing by any health institution.

scholarly journals 3D-Printed Connector for Revision Limb Salvage Surgery in Long Bones Previously Using Customized Implants

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 707
Author(s):  
Jong-Woong Park ◽  
Hyun-Guy Kang ◽  
June-Hyuk Kim ◽  
Han-Soo Kim
Keyword(s):  
Limb Salvage ◽  
Salvage Surgery ◽  
Revisional Surgery ◽  
Limb Salvage Surgery ◽  
Musculoskeletal Tumor ◽  
Musculoskeletal Tumor Society ◽  
Proximal Ulna ◽  
Custom Made ◽  
Orthopedic Oncology ◽  
3D Printed

In orthopedic oncology, revisional surgery due to mechanical failure or local recurrence is not uncommon following limb salvage surgery using an endoprosthesis. However, due to the lack of clinical experience in limb salvage surgery using 3D-printed custom-made implants, there have been no reports of revision limb salvage surgery using a 3D-printed implant. Herein, we present two cases of representative revision limb salvage surgeries that utilized another 3D-printed custom-made implant while retaining the previous 3D-printed custom-made implant. A 3D-printed connector implant was used to connect the previous 3D-printed implant to the proximal ulna of a 40-year-old man and to the femur of a 69-year-old woman. The connector bodies for the two junctions of the previous implant and the remaining host bone were designed for the most functional position or angle by twisting or tilting. Using the previous 3D-printed implant as a taper, the 3D-printed connector was used to encase the outside of the previous implant. The gap between the previous implant and the new one was subsequently filled with bone cement. For both the upper and lower extremities, the 3D-printed connector showed stable reconstruction and excellent functional outcomes (Musculoskeletal Tumor Society scores of 87% and 100%, respectively) in the short-term follow-up. To retain the previous 3D-printed implant during revision limb salvage surgery, an additional 3D-printed implant may be a feasible surgical option.

A novel parameterized digital-mask generation method for projection stereolithography in tissue engineering

2018 ◽  
Vol 24 (6) ◽  
pp. 935-944 ◽  
Author(s):  
Mingke Li ◽  
Wangyu Liu
Keyword(s):  
Computer Aided Design ◽  
Boundary Region ◽  
Additive Manufacture ◽  
3D Scaffold ◽  
Content Type ◽  
Parameterized Design ◽  
High Efficient ◽  
Unit Cells ◽  
Conventional Methods ◽  
Projection Stereolithography

PurposeThe purpose of this paper is to present the novel parameterized digital-mask generation method which is aimed at enhancing bio-scaffold’s fabricating efficiency with digital micro-mirror device (DMD)-based systems.Design/methodology/approachA method to directly generate the digital masks of bio-scaffolds without modeling the entire 3D scaffold models is presented. In most of the conventional methods, it is inefficient to dynamically modify the size of the structural unit cells during design, because it relies more or less on commercial computer aided design (CAD) platforms. The method proposed in this paper can achieve high efficient parameterized design, and it is independent from any CAD platforms. The generated masks in binary bitmap format can be used by the DMD-based to achieve scaffold’s additive manufacture. In conventional methods, the Boolean operation of the external surface and the internal architectures would result in the damage of unit cells in boundary region. These damaged unit cells not only lose its original mechanical property but also cause numbers of gaps and isolated features that would reduce the geometric accuracy of the fabricated scaffolds; the proposed method in this paper provides an approach to tackle this defect.FindingsThe results show that the proposed method can improve the digital masks generation efficiency.Practical implicationsThe proposed method can serve as an effective supplement to the slicing method in additive manufacture. It also provides a way to design and fabricate scaffolds with heterogeneous architectures.Originality/valueThis paper gives supports to fabricate bio-scaffold with DMD-based systems.

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