Light responsive hydrogels enable fast and precise control of soft materials

Tampere University

Researchers at Tampere University have demonstrated that light can be used to precisely reshape soft materials without mechanical contact. They have developed light responsive hydrogel thin films that enable programmable surfaces with high sensitivity, rapid response, precise spatial control and reversibility. The technology opens new possibilities for tunable devices in photonics, sensing and biomedicine.

Until now, responses in hydrogel films have typically been limited to timescales of tens of seconds and spatial resolutions of tens of micrometres – about the thickness of a fine human hair – restricting practical applications. In contrast, the Smart Photonic Materials research group has achieved control on sub‑second timescales and sub‑micron resolution, marking a significant advance in speed and precision. 

Light-responsive hydrogels are particularly attractive for mimicking dynamic microstructures found in nature. The materials absorb and release water when exposed to light, enabling accurate and remote actuation in lightweight structures. Such properties are well suited for applications including soft micro‑robots, remote drug delivery systems and active cell culture platforms. 

The researchers’ approach provides a general platform for creating dynamic, programmable surfaces that combine fast response, high spatial control and full reversibility in a soft material. 

“The fast response additionally allows creation of ‘living surfaces’, where protrusions are constantly moving and capable of transporting objects on the surface,” says lead author Doctoral Researcher Matias Paatelainen from Tampere University.  

According to Paatelainen, the innovation could enable simpler and more adaptive optical devices, smart sensing surfaces and biomedical platforms that more closely resemble natural biological behaviour. 

“These materials bring us one step closer to mimicking the dynamism of biological microenvironments, offering cyclic mechanical stimulation to cells at heartbeat-like frequencies. There is still a long way to go, but we see strong potential for creating adaptive, dynamic cell culture and reconfigurable microfluidic platforms and beyond, all driven remotely with light,” adds Professor Arri Priimägi from Tampere University. 

The findings also point toward future light‑responsive cell culture platforms capable of simulating mechanical cues associated with physiological processes such as breathing and heartbeat. Development of these features continues within the GelCell project, funded by Novo Nordisk.