3D Matter Made to Order

What do molecules have to do with your smartphone display? Quite a lot. Organic light-emitting diodes (OLEDs) enable the bright and vibrant images we see every day.

In the latest episode of our “Explain Like I’m Five” series, Lisa Janz, Cluster Doctoral Researcher at Karlsruhe Institute of Technology (KIT), explains how OLEDs work and why molecular design is key to their performance. She shows how organic molecules convert electrical energy into light and why blue emitters are particularly challenging. Their higher energy makes them more prone to degradation. In her research, Lisa develops new luminescent molecules for OLEDs, using computational methods and advanced 3D printing techniques to integrate promising materials into devices. Her goal is more energy-efficient, durable displays with brilliant colors.

Watch the video here.

A new Cluster publication in Advanced Materials introduces a strategy for forming soft hydrogels more reliably. Doctoral Researchers Julian A. Serna, Michelle J. Iwohn, and Maike Schliephake, together with PI Pavel Levkin, temporarily “protect” thiols with S-nitrosothiols to prevent thiol-maleimide reactions from starting before polymer components are fully mixed.

This controlled delay enables homogeneous mixing before crosslinking is triggered on demand, resulting in more uniform hydrogels with tunable stiffness across a range relevant for biological tissues. The approach also supported 3D cell encapsulation in a cell-adhesive system, with cytocompatibility depending on formulation and cell type. As S-nitrosothiols can release nitric oxide-related species, the method could also enable future materials combining controlled network formation with local biochemical signaling.

© Serna, Iwohn, Seifermann, Heißler, Schliephake, Dopp, Muhle-Goll, Levkin, Advanced Materials (2026), CC BY 4.0

In a new Cluster publication in the Journal of the American Chemical Society, Postdoctoral Researcher Linh Duy Thai and PI Christopher Barner-Kowollik present a light-controlled thiol–yne photoclick reaction that works without added catalysts.

The team uses a spirothiopyran photoswitch as a photoactivatable thiol source. Upon irradiation, the molecule switches into a reactive form that enables thiol–yne click chemistry with activated alkynes. In the dark, the reaction remains switched off, providing precise temporal control.

The reaction proceeds under mild, oxygen-tolerant conditions and was demonstrated for postpolymerization modification and photopolymerization. This catalyst-free approach opens new possibilities for light-driven 3D printing and the controlled design of functional photomaterials.

© Thai, Kirschhöfer, Roth, Barner-Kowollik, Journal of the American Chemical Society (2026), CC BY 4.0

On August 11–12, 2026, the Cluster hosted its 3D Printing Summer Workshop at the ZEISS Innovation Hub. The two-day program is tailored to young women between 13 and 19 years of age and aims to give school students with an interest in STEM an insight into how 3D printing works.

During the workshop, participants followed the complete workflow of 3D printing from their first idea and initial design sketch through CAD modelling to the fabrication of their final 3D-printed object.

We would like to thank all participants for two exciting days and for their enthusiasm and creativity. Our special thanks go to the ZEISS Innovation Hub as well as to Carl Roth for their support of this year’s summer program.

A new Cluster publication from the lab of Principal Investigator Daniela Duarte Campos, featuring the work of Cluster Doctoral Researcher Alexandre Taoum and Mario Wisbar, Cluster Postdoctoral Researcher Freiderike Dehli, as well as Cluster Alumnus Ole Thaden, demonstrates that human-derived low-serum FBS alternatives can support the maintenance and differentiation of stromal cell phenotypes.

The use of animal-free serum alternatives represents an important step toward clinically relevant systems. The authors demonstrate that human-derived serum alternatives are worth exploring in corneal bioprinting and regenerative ophthalmology.

© Taoum, A., Oster, J.S., Thaden, O. et al., Sci Rep 16, 18874 (2026), CC BY 4.0

A new Cluster publication from the lab of Principal Investigator Daniela Duarte Campos, featuring the work of Cluster Postdoctoral Researcher Friederike Dehli, presents a new class of photocrosslinkable, hydrazone-based bioinks developed from two modified polymers.

The authors’ modular approach leads to distinct material properties of photocrosslinked hydrogels when exchanging hydrazide substituents. The developed materials are processable with droplet-based printing and sustain cell spreading in 3D cell culture of human fibroblasts. Embedded cells display notable differences in morphology, suggesting that the materials provide unique mechanical cues that result in varied cellular responses. The versatility and adjustability of this system establish it as a unique tool with broad potential applications, particularly in mechanobiology, where precise control over matrix properties is essential for investigating cell-matrix interactions.

© Friederike Dehli et al 2026 Biofabrication 18 025042, CC BY 4.0