Xi’an Jiaotong University: Chinese Researchers Create New Hydrogel 3D Printing System

In the recently published ‘Hydrogel 3D printing with the capacitor edge effect,’ authors Jikun Wang, Tongqing Lu, Meng Yang, Danqi Sun, Yukun Xia and Tiejun Wang further explore the use of hydrogels with progressive fabrication techniques, and outline their new method for overcoming current challenges.

While hydrogels are often central to bioprinting today, these structures are also used in many other applications like manufacturing diapers, contact lenses, and drug delivery. The medical field is of course benefiting from their continued use, however, in tissue engineering. Hydrogels have also branched off into numerous different categories such as functional, responsive, double-network, tough, along with those included in soft sensors, actuators, and ionic devices.

The authors put the issue at hand very clearly here: as hydrogels become more advanced, so should the techniques being used to create them. In this study, they detail a new way to pattern liquids with the capacitor edge effect, offering a method they expect to be applied for creating comprehensive hydrogel 3D printing systems. They go into detail regarding techniques for rapid prototyping of:

  • Hydrogel scaffolds
  • Hydrogel composites that are temperature-sensitive
  • Ionic high-integrity hydrogel display device

The principles of PLEEC: An asymmetric capacitor is separated by a dielectric layer.

In using the capacitor edge effect (PLEEC), hydrogels can be created with many different properties, and cross-linking is possible too with a variety of mechanisms and materials.

“The asymmetric design of the capacitor makes it possible to build a real 3D object rather than merely 2D patterns within two electrodes,” state the researchers. “We build a 3D printing system based on the new method and demonstrate a series of printed hydrogel structures including a hydrogel scaffold, a hydrogel composite, and hydrogel ionic devices.”

Essentially, capacitors store electrical charges. Here, the authors study and compare both symmetric and asymmetric capacitors—with the end goal of producing the asymmetric forms to both ‘trap and control liquids in an open space.’ Their 3D printing system for hydrogels is made up of seven parts:

  1. Mechanical module
  2. PLEEC panel
  3. Solution-adding unit
  4. Curing platform
  5. Curing unit
  6. Power supply
  7. Control module

The researchers use an Arduino Mega 2560 R3 to control the system, with three 42-stepper motors controlled by Leadshine DM542 to actuate the three sliding rails. They also use a high-voltage power supply (Trek 610E), applied at 3000 V at 1 kHz.

Polymerization can be achieved through heat curing, UV curing, or ion-exchange curing, and hydrogels are easily patterned into different composites. The researchers state that this method of curing allows for ‘excellent integrity and bonding.’

Hydrogel 3D printing system with PLEEC. (Photo credit: Jikun Wang, Xi’an Jiaotong University.)

“The precision of our printing technique can be further improved if a dielectric layer with higher permittivity is used or if the apparatus is immersed in an environment with higher electrical breakdown strength,” concluded the researchers. “The activation voltage can also be markedly decreased if a more advanced technique is used to fabricate a much thinner layer. If the pixel size can be further decreased to micrometer scale or smaller, this printing technique has great potential to print very complex and precise hydrogel structures such as artificial tissues, soft metamaterials, soft electronics, and soft robotics.”

3D printing hydrogels is popular in many research labs today as bioprinting continues to reach new heights. While tissue engineering is a very real science that is already helping many patients today as they receive 3D printed implants and medical professionals rely on 3D printed medical models and surgical guides, the ultimate goal is in actually 3D printing human organs. Currently though, hydrogels can be used in a wide range of applications. Find out more about use of the capacitator edge effect here.

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[Source / Images: ‘Hydrogel 3D printing with the capacitor edge effect’]

Hebrew University and Yissum Developing Novel Technology Platform for 3D Printing Personalized Medicine

Yissum, which is the Hebrew University of Jerusalem‘s technology transfer company and handles the patenting and commercialization of any inventions produced there, has had a hand in many unique 3D printing innovations, such as Nano Dimension’s conductive nano-inks and a process to generate hybrid machine elements. Last year, the company, which was founded in 1964 and has licensed over 900 technologies and registered over 10,000 patents covering 2,800 inventions, introduced a novel technology platform for 3D printing personalized food, and has now moved on to 3D printing personalized medicine.

The company, which is only the third of its kind, builds a bridge between academic research and its worldwide community of entrepreneurs, investors, and industry. It’s responsible for spinning more than 135 total companies. Yissum recently announced a novel technology platform for fabricating 3D printed drug capsules, and presented it today at the university’s 2nd annual 3D Printing and Beyond conference, which is sponsored by Yissum, the university, and the Jerusalem Development Authority.

Professor Shlomo Magdassi, head of the university’s 3D and Functional Printing Center and a member of the Center for Nanoscience and Nanotechnology and Institute of Chemistry, worked with Dr. Ofra Benny, a researcher at the university’s Institute for Drug Research, to develop the innovative drug 3D printing technology platform.

“Professor Magdassi and Dr. Benny’s research is an excellent example of the  kind of interdisciplinary transformational inventions that originate  from the Hebrew University,” said Dr. Yaron Daniely, CEO and President of Yissum. “This technology is bringing us closer to a future in which the medical field can offer personalized, patient-centered care.”

The technology is based on custom 3D printed hydrogels with delayed release characteristics, and allows for a complex design of drug delivery systems that is not currently available in the more traditional pharmaceutical manufacturing techniques.

Dr. Magdassi already has plenty of experience with 3D printed hydrogels and other unique 3D printable materials. 3D hydrogels are hydrophilic polymeric networks that are cross-linked by either chemical covalent bonds, physical interactions, or a combination. Because of these crosslinks between polymer chains and their hydrophilic nature, hydrogels can actually swell up to a hundred times, or even a thousand, of their dried mass without needing to be dissolved in water, and they are an ideal material for biomedical applications.

Yissum’s company mission is to take transformational technologies and innovations and convert them into commercial solutions that address the most urgent challenges in our world, in order to benefit society. I’d say this new 3D printing platform fits the bill – the approach makes it possible to 3D print customized medications out of hydrogel objects that can change shape, expand, and even activate on a delayed schedule.

The novel new 3D printing platform can not only achieve complex release profiles and structures of drugs, but it can also personalize prescription medicines, so doctors can more accurately tailor the dosage levels and exposure of medications for different patients. Thanks to 3D printing, medication may not have to be one-size-fits-all.

Professor Magdassi and Dr. Benny presented their work at the 3D Printing and Beyond conference today, which Professor Magdassi helps organize with Dr. Michael Layani. The conference brings together a range of researchers and industry leaders from around the world to discuss and learn more about the latest advances in defense-related technologies, electronics, and pharmaceuticals, in addition to 3D printed innovations like automotive parts and food.

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