In this edition of our additive manufacturing research digest CrAMmed, academics from Asia, Europe, and the U.S. integrate additive manufacturing and 3D bioprinting to develop regenerative nose cartilage as well as complex presurgical tumor models.
Also, 3D printed metamaterials are explored to address aircraft noise pollution as well as to further laboratory chemical supplies.
3D printed surgical guides, implants, and bioinks
3D printed surgical guides have been used for the successful execution of several complex medical procedures. Recently, a team of Chinese researchers from the Tongji Medical College of Huazhong University of Science and Technology (HUST) 3D printed benign tumors models (macroadenoma) found in ten patients.
In the paper, “A small 3D printing model of macroadenomas for endoscopic endonasal surgery” published in Springer Link, the medical team found the models useful for understanding the complicated anatomy of the sphenoid sinus, the upper posterior wall of the nasal cavity as well as the tumor location. This is expected to help the patients get an accurate prognosis.
Xiaobing Jiang, of the department of neurosurgery at Union Hospital of Tongji Medical College, wrote, “An accurate model of the target tumor structure is a major prerequisite for a successful [pituitary adenoma] resection, especially for macroadenomas, as this may avoid disastrous complications.”
Also within the nasal region, researchers at Pohang University of Science and Technology (POSTECH) in South Korea, have developed customized 3D bioprinted nasal implants for cartilage tissue regeneration in rhinoplasties (aka nose jobs).
Hee-Gyeong Yi is the first author of the research paper “Three-dimensional printing of a patient-specific engineered nasal cartilage for augmentative rhinoplasty” published in SAGE Journals.
In Italy, a team from Istituto Ortopedico (Orthopedic Institute) have 3D bioprinted meniscus tissue which acts as a shock absorber between the shinbone and thighbone. The results can be found in the paper “Patient-specific meniscus prototype based on 3D bioprinting of human cell-laden scaffold” published in the Bone & Joint Journal.
Such 3D printed implants and scaffolds are created using specialized bioinks. Researchers from Zhejiang University (ZJU) in China, have reviewed the printability of current bioinks in a paper entitled “Trends on physical understanding of bioink printability” published in Springer Link.
The authors, Jun Yin, Dengke Zhao, and Jingyi Liu, based their review on a recent bioink study from Huang’s research group from the University of Florida. The ZJU researchers found concluded that “the printability of bioinks is largely ignored and still needs to be carefully examined to enable robotic bioprinting.”
Moreover, South Korea’s Severance Hospital has proposed a novel semi-automated method for fabricating 3D printed ocular prosthesis in the paper “Semi-automated fabrication of customized ocular prosthesis with three–dimensional printing and sublimation transfer printing technology” published in Nature.
James Pierce, a Graduate Assistant at the University of Nebraska, Ohama has published the study “Efficacy of Assistive Devices Produced with Additive Manufacturing”. In this, Pierce designed and 3D printed wrist splints for comparison against conventional medical assistive devices.
A 3D printed mute button
In metamaterials, mechanical engineers at Boston University (BU) are tackling noise pollution with 3D printing and acoustics. In the study “Ultra-open acoustic metamaterial silencer based on Fano-like interference” published in APS Physics, the engineers 3D printed ringlike structures (using ABS) composed of subwavelength unit-cell structures.
These structures were able to cancel 94% of the sound of loudspeakers playing at full volume. Reza Ghaffarivardavagh, a Ph.D. student in the Department of Mechanical Engineering and co-author of the study said, “Sound is made by very tiny disturbances in the air. So, our goal is to silence those tiny vibrations.”
“If we want the inside of a structure to be open air, then we have to keep in mind that this will be the pathway through which sound travels.”
Continuing the theme of advanced materials, Johanna Schwartz and Andrew J. Boydston from the Department of Chemistry at the University of Wisconsin-Madison have developed a single vat polymerization process to 3D print objects using multicomponent photoresins.
Published in Nature, “Multimaterial actinic spatial control 3D and 4D printing”, details that most multi-material 3D printing methods use separate reservoirs. With a “one-pot” approach, the chemists were able to control the polymerization of different resins which led to different textures in the final 3D printed object. This could lead to more complex medical devices.
Also in Chemistry, a team at the University College London (UCL) School of Pharmacy have developed a 3D printed a low-cost continuous flow system to be used with existing laboratory equipment. The process for this system is presented in the paper “Modular 3D Printed Compressed Air Driven Continuous-Flow Systems for Chemical Synthesis” published in ChemRxiv.
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Featured image shows the CrAMmed logo over Reza Ghaffarivardavagh (front center) holding two of the open, ringlike structures over his ears while Stephan Anderson (left), Xin Zhang (rear center), and Jacob Nikolajczyk (right) make a racket. Photo by Cydney Scott/Boston University.