Engineers 3-D print shape-shifting smart gel

  • Engineers have invented a “4D printing” method for a smart gel that could lead to the development of “living” structures in human organs and tissues, soft robots and targeted drug delivery.
  • The 4D printing approach here involves printing a 3D object with a hydrogel (water-containing gel) that changes shape over time when temperatures change.
  • This is fast, scalable, high-resolution 3D printing of hydrogels, which remain solid and retain their shape despite containing water. Hydrogels are everywhere in our lives, including in Jell-O, contact lenses, diapers and the human body.
  • The smart gel could provide structural rigidity in organs such as the lungs, and can contain small molecules like water or drugs to be transported in the body and released.
  • It could also create a new area of soft robotics, and enable new applications in flexible sensors and actuators, biomedical devices and platforms or scaffolds for cells to grow.
  • The engineers used a lithography-based technique that’s fast, inexpensive and can print a wide range of materials into a 3D shape.
  • It involves printing layers of a special resin to build a 3D object. The resin consists of the hydrogel, a chemical that acts as a binder, another chemical that facilitates bonding when light hits it and a dye that controls light penetration.
  • The engineers learned how to precisely control hydrogel growth and shrinkage.
  • In temperatures below 32 degrees Celsius (about 90 degrees Fahrenheit), the hydrogel absorbs more water and swells in size. When temperatures exceed 32 degrees Celsius, the hydrogel begins to expel water and shrinks.
  • The objects they can create with the hydrogel range from the width of a human hair to several millimeters long.
  • The engineers also found that they can grow one area of a 3D-printed object creating and programming motion by changing temperatures.
  • If we have full control of the shape, then we can program its function, the power of 3D printing of shape-shifting material. You can apply this principle almost everywhere.



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