Dual-material 3D printed metamaterials with tunable mechanical properties for patient-specific tissue-mimicking phantoms

Three dimensional (3D) printing allows additive manufacturing of patient specific scaffolds with varying pore size and geometry. Such porous scaffolds, made of 3D-printable bone-like calcium phosphate cement (CPC), are suitable for bone augmentation due to their benefit for osteogenesis. Their pores allow blood-, bone- and stem cells to migrate, colonize and finally integrate into the adjacent tissue. Furthermore, the pore size affects the scaffold’s stability. Since scaffolds in maxillofacial surgery have to withstand high forces within the jaw, adequate mechanical properties are of high clinical importance. Although many studies have investigated CPC for bone augmentation, the ideal porosity for specific indications has not been defined yet. We investigated 3D printed CPC cubes with increasing pore sizes and different printing orientations regarding cell migration and mechanical properties in comparison to commercially available bone substitutes. Furthermore, by investigating clinical cases, the scaffolds’ designs were adapted to resemble the in vivo conditions as accurately as possible. Our findings suggest that the pore size of CPC scaffolds for bone augmentation in maxillofacial surgery necessarily needs to be adapted to the surgical site. Scaffolds for sites that are not exposed to high forces, such as the sinus floor, should be printed with a pore size of 750 µm to benefit from enhanced cell infiltration. In contrast, for areas exposed to high pressures, such as the lateral mandible, scaffolds should be manufactured with a pore size of 490 µm to guarantee adequate cell migration and in order to withstand the high forces during the chewing process.

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Tissue Engineering Scaffolds Fabricated in Dissolvable 3D-Printed Molds for Patient-Specific Craniofacial Bone Regeneration

Journal of Functional Biomaterials ◽

10.3390/jfb9030046 ◽

2018 ◽

Vol 9 (3) ◽

pp. 46 ◽

Cited By ~ 4

Author(s):

Angela de la Lastra ◽

Katherine Hixon ◽

Lavanya Aryan ◽

Amanda Banks ◽

Alexander Lin ◽

...

Keyword(s):

Bone Grafting ◽

Complex Geometry ◽

Dry Weight ◽

Patient Specific ◽

Tissue Engineering Scaffolds ◽

Defect Site ◽

3D Printed ◽

Hydrogel Swelling ◽

Specific Tissue ◽

Craniofacial Defects

The current gold standard treatment for oral clefts is autologous bone grafting. This treatment, however, presents another wound site for the patient, greater discomfort, and pediatric patients have less bone mass for bone grafting. A potential alternative treatment is the use of tissue engineered scaffolds. Hydrogels are well characterized nanoporous scaffolds and cryogels are mechanically durable, macroporous, sponge-like scaffolds. However, there has been limited research on these scaffolds for cleft craniofacial defects. 3D-printed molds can be combined with cryogel/hydrogel fabrication to create patient-specific tissue engineered scaffolds. By combining 3D-printing technology and scaffold fabrication, we were able to create scaffolds with the geometry of three cleft craniofacial defects. The scaffolds were then characterized to assess the effect of the mold on their physical properties. While the scaffolds were able to completely fill the mold, creating the desired geometry, the overall volumes were smaller than expected. The cryogels possessed porosities ranging from 79.7% to 87.2% and high interconnectivity. Additionally, the cryogels swelled from 400% to almost 1500% of their original dry weight while the hydrogel swelling did not reach 500%, demonstrating the ability to fill a defect site. Overall, despite the complex geometry, the cryogel scaffolds displayed ideal properties for bone reconstruction.

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Metallographic and Fractographic Evaluation of 3D-Printed Titanium Samples to Eliminate Unsatisfactory Mechanical Properties

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.270.212 ◽

2017 ◽

Vol 270 ◽

pp. 212-217

Author(s):

Michaela Fousová ◽

Tereza Stejskalova ◽

Dalibor Vojtěch

Keyword(s):

Mechanical Properties ◽

Titanium Alloy ◽

3D Printing ◽

Process Parameters ◽

Patient Specific ◽

Medical Implants ◽

Laser Melting ◽

Patient Specific Implants ◽

3D Printed ◽

Set Up

Czech company ProSpon spol. s r.o. has introduced 3D printing technology in its production in 2015. This company operates in the field of development, manufacture and distribution of medical implants and instruments for orthopedics, traumatology and surgery. Therefore, the current intention is to employ Selective Laser Melting (SLM) technology for production of complex and patient-specific implants from titanium alloy Ti-6Al-4V. Nevertheless, first series of produced test specimens suffered from very low plasticity insufficient for the intended application. The reduction in elongation was almost 7fold compared to conventionally used wrought standard. From that reason, specimens were subjected to fractographic evaluation of fracture surfaces, but also metallographic evaluation. The main cause of the identified problem turned out to be porosity originating from inappropriate set-up of the machine. After the adjustment of process parameters new series of specimens were prepared in which the porosity was already significantly lower. Consequently, mechanical properties reached higher and better values.

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3D printed three-dimensional metallic microlattices with controlled and tunable mechanical properties

Additive Manufacturing ◽

10.1016/j.addma.2021.101856 ◽

2021 ◽

Vol 39 ◽

pp. 101856

Author(s):

Mohammad Sadeq Saleh ◽

Chunshan Hu ◽

Jacob Brenneman ◽

Al Muntasar Al Mutairi ◽

Rahul Panat

Keyword(s):

Mechanical Properties ◽

Three Dimensional ◽

3D Printed ◽

Tunable Mechanical Properties

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DLP 3D printing of Dexamethasoneincorporated PEGDA-based photopolymers: compressive properties and drug release

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2020-3105 ◽

2020 ◽

Vol 6 (3) ◽

pp. 406-409

Author(s):

Robert Mau ◽

Thomas Reske ◽

Thomas Eickner ◽

Niels Grabow ◽

Hermann Seitz

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Drug Release ◽

Drug Loading ◽

Patient Specific ◽

Burst Release ◽

Compressive Properties ◽

Drug Load ◽

Polyethylene Glycol Diacrylate ◽

3D Printed

AbstractPhotopolymerizing, high-resolution 3D printing methods such as Stereolithography (SLA) or Digital Light Processing (DLP) are very promising for the manufacturing of drug-incorporated, patient specific implants. However, a drug-load may be limited by adequately solubility of the active pharmaceutical ingredient (API) in the photopolymer. Furthermore, a drug-load may affect the mechanical properties of the material negatively. Here, we investigate the DLP 3D printing of drugincorporated photopolymers. Polyethylene glycol diacrylate (PEGDA, Mn = 700 g/mol) is used as matrix polymer and Dexamethasone (DEX) is used for drug-loading (10 g/L and 20 g/L). Compressive properties, drug release and drug stability of 3D printed test samples were analyzed. DEX was found to be sparingly soluble in the PEGDA-based photopolymer. Not all drug particles can be dissolved at a concentration of 20 g/L and a slurry-like suspension is formed. Drug-incorporated photopolymers of 10 g/L (solution) and 20 g/L (suspension) were processed successfully via DLP. The higher the drug-load, the lower the compressive strength. Mechanical properties can be improved via a post-curing in a UV light curing box. Drug-incorporated 3D printed test samples show burst-release of DEX. The post-curing process does not affect drug release. DEX degrades in 3D-printed test samples significantly (~ 30 %) over a several days time period.

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Incorporating Aminated Nanodiamonds to Improve the Mechanical Properties of 3D-Printed Resin-Based Biomedical Appliances

Nanomaterials ◽

10.3390/nano10050827 ◽

2020 ◽

Vol 10 (5) ◽

pp. 827 ◽

Cited By ~ 3

Author(s):

Utkarsh Mangal ◽

Ji-Young Seo ◽

Jaehun Yu ◽

Jae-Sung Kwon ◽

Sung-Hwan Choi

Keyword(s):

Mechanical Properties ◽

Wear Resistance ◽

Contact Angles ◽

Patient Specific ◽

Water Contact ◽

3D Printed ◽

Printed Materials ◽

Biological Environment ◽

Pmma Resin ◽

Important Objective

The creation of clinically patient-specific 3D-printed biomedical appliances that can withstand the physical stresses of the complex biological environment is an important objective. To that end, this study aimed to evaluate the efficacy of aminated nanodiamonds (A-NDs) as nanofillers in biological-grade acrylate-based 3D-printed materials. Solution-based mixing was used to incorporate 0.1 wt% purified nanodiamond (NDs) and A-NDs into UV-polymerized poly(methyl methacrylate) (PMMA). The ND and A-ND nanocomposites showed significantly lower water contact angles (p < 0.001) and solubilities (p < 0.05) compared to those of the control. Both nanocomposites showed markedly improved mechanical properties, with the A-ND-containing nanocomposite showing a statistically significant increase in the flexural strength (p < 0.001), elastic modulus (p < 0.01), and impact strength (p < 0.001) compared to the control and ND-containing groups. The Vickers hardness and wear-resistance values of the A-ND-incorporated material were significantly higher (p < 0.001) than those of the control and were comparable to the values observed for the ND-containing group. In addition, trueness analysis was used to verify that 3D-printed orthodontic brackets prepared with the A-ND- and ND-nanocomposites exhibited no significant differences in accuracy. Hence, we conclude that the successful incorporation of 0.1 wt% A-ND in UV-polymerized PMMA resin significantly improves the mechanical properties of the resin for the additive manufacturing of precisive 3D-printed biomedical appliances.

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Modelling and manufacturing of 3D-printed, patient-specific, and anthropomorphic gastric phantoms: a pilot study

Scientific Reports ◽

10.1038/s41598-020-74110-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Jinhee Kwon ◽

Joonmyeong Choi ◽

Sangwook Lee ◽

Minkyeong Kim ◽

Yoon Kyung Park ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Patient Specific ◽

Registration Accuracy ◽

Shape Accuracy ◽

Shape Registration ◽

Interventional Devices ◽

Accuracy Difference ◽

3D Printed ◽

The Mean

Abstract Interventional devices including intragastric balloons are widely used to treat obesity. This study aims to develop 3D-printed, patient-specific, and anthropomorphic gastric phantoms with mechanical properties similar to those of human stomach. Using computed tomography gastrography (CTG) images of three patients, gastric phantoms were modelled through shape registration to align the stomach shapes of three different phases. Shape accuracies of the original gastric models versus the 3D-printed phantoms were compared using landmark distances. The mechanical properties (elongation and tensile strength), number of silicone coatings (0, 2, and 8 times), and specimen hardness (50, 60, and 70 Shore A) of three materials (Agilus, Elastic, and Flexa) were evaluated. Registration accuracy was significantly lower between the arterial and portal phases (3.16 ± 0.80 mm) than that between the portal and delayed phases (8.92 ± 0.96 mm). The mean shape accuracy difference was less than 10 mm. The mean elongations and tensile strengths of the Agilus, Elastic, and Flexa were 264%, 145%, and 146% and 1.14, 1.59, and 2.15 MPa, respectively, and their mechanical properties differed significantly (all p < 0.05). Elongation and tensile strength assessments, CTG image registration and 3D printing resulted in highly realistic and patient-specific gastric phantoms with reasonable shape accuracies.

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