Hydrogels That Grow Like Living Tissues

A team of researchers in Singapore and the US have created hydrogels that grow like biological tissues.

AsianScientist (Dec. 27, 2017) – Scientists from Nanyang Technological University, Singapore (NTU Singapore) and Carnegie Mellon University (CMU) have found a way to direct the growth of hydrogel, a jelly-like substance, to mimic plant or animal tissue structure and shapes. They published their findings in the journal Proceedings of the National Academy of Sciences.

In nature, plant or animal tissues are formed as new biomass is added to existing structures. The resulting shapes of the structures arise as a consequence of different parts of those tissues growing at different rates.

In this study, the team of researchers led by NTU President-designate Professor Subra Suresh and CMU’s Professor Jimmy K. Hsia mimicked the behavior of biological tissues in nature, demonstrating that by manipulating the oxygen concentration within hydrogels, the pattern and growth rate of hydrogels could be controlled. The team found that higher oxygen concentrations slowed down the cross-linking of chemicals in the hydrogel, which could be used to inhibit growth at specific areas.

Mechanical constraints such as soft wire, or a glass substrate which chemically binds with the gel, can also be used to manipulate the self-assembly and formation of hydrogels into complex structures, allowing the researchers to create hydrogels in complex three-dimensional (3D) shapes. Such complex organ structures are essential for performing specialized body functions. For example, the small intestines of humans are covered with microscopic folds known as villi, which increase the gut’s surface area for more efficient absorption of food nutrients.

The researchers explained that their technique differs from previous methods which create 3D structures by printing or removing layers of materials. Instead, their method relies on continuous polymerization of monomers inside the porous hydrogel, similar to the process of continuous enlargement and proliferation of living cells in organic tissues. The team has filed patents for their technology at CMU and NTU.

“Greater control of the growth and self-assembly of hydrogels into complex structures offers a range of possibilities in medical and robotics fields. One field that stands to benefit is tissue engineering, where the goal is to replace damaged biological tissues, such as in knee repairs or in creating artificial livers,” said Suresh.

The article can be found at: Huang et al. (2017) Controlled Molecular Self-assembly of Complex Three-dimensional Structures in Soft Materials.


Source: Nanyang Technological University.
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