March 2, 2021

For a long time, tissue engineering has relied on geometrically static scaffolds that are seeded with cells in the lab to make new tissues and even organs.

Usually, the scaffold material is a biodegradable polymeric structure that is provided with cells, and if the cells receive the proper nutrients, then they develop into tissue as the base scaffold biodegrades. However, this model does not take into account the unusually dynamic morphological processes that form the basis of natural tissue growth.

Currently, scientists at the University of Illinois at Chicago (UIC) have designed new 4D hydrogels – 3D materials with the potential to change their shape over time in response to stimuli – that can transform multiple times. on demand or preprogrammed in response to external trigger signals.

A new study published by UIC scientists in the Advanced sciences journal, and led by Eben Alsberg, demonstrates that these new materials could help develop tissues that more closely mimic their natural counterparts, where natural materials are subjected to forces that induce movement during their development.

Hydrogels can be programmed or induced to undergo multiple controllable shape changes over time. This strategy creates experimental conditions to mimic or partially stimulate the various continuous shape changes that developing or scarring tissue undergo, and it can allow us to study morphogenesis and also help us design tissue architectures that more closely resemble to native tissues..

Eben Alsberg, corresponding study author and Richard and Loan Hill Professor of Biomedical Engineering, University of Illinois at Chicago

The new material was developed using different hydrogels that shrink or swell at varying rates and degrees in response to the concentration of calcium or the presence of water. By creating intricate layering patterns, the team can orient the conglomerate material to somehow bend as the layers shrink and / or swell.

The shape of these materials can be changed by adjusting, for example, the amount of calcium present.

Eben Alsberg, corresponding study author and Richard and Loan Hill Professor of Biomedical Engineering, University of Illinois at Chicago

Alsberg is also professor of orthopedics, pharmacology and mechanical and industrial engineering at UIC.

During the experiments, the researchers were able to transform the hydrogel into pockets similar in shape to alveoli, the small sac-like structures in the lungs where gas exchange occurs.

Alsberg hydrogels not only change their architecture multiple times, but are also highly cytocompatible, i.e. they can have cells integrated and cells stay alive, which various current 4D materials are incapable of. to do.

We really can’t wait to push the boundaries of what our unique hydrogel systems can do in terms of tissue engineering..

Aixiang Ding, co-first author of the study and postdoctoral research associate, University of Illinois at Chicago

Oju Jeon, professor and researcher at UIC, is also co-first author of the study. The other co-authors of the article are Rui Tang, Yu Bin Lee and Sang Jin Lee of UIC.

This study was funded by grants from the National Institute of Health’s National Institute of Arthritis and Musculoskeletal and Skin Diseases (R01AR069564, R01AR066193), the National Institute of Biomedical Imaging and Bioengineering (R01EB023907) and the National Heart, Lung and Blood Institute (T32HL134622) ).

Refer to the journalin this :

Ding, A., et al. (2021) Multistage and reversible 4D hydrogel actuators loaded with cells to mimic dynamic tissue morphogenesis. Advanced sciences. doi.org/10.1002/advs.202004616.

Source: https://www.uic.edu/