Researchers from the University of Macau and their collaborators have developed a new digital microfluidic platform aimed at improving three-dimensional (3D) cell culture. The study, published in Microsystems & Nanoengineering in 2025 (DOI: 10.1038/s41378-025-01098-9), addresses challenges faced by traditional two-dimensional (2D) cell cultures, which often fail to replicate the complex environments found in real tissues.
The research team used a one-step micro-nano 3D printing process to fabricate microstructures directly onto microfluidic electrodes. This method allows for controlled droplet movement, efficient cell capture, and rapid formation of 3D cell spheroids. The chip demonstrated stable operation and maintained high cell viability for up to 72 hours.
The core innovation lies in merging digital microfluidics with integrated 3D microstructures using projection stereolithography. This technique enables the simultaneous printing of the dielectric layer, confinement fences, and micro-well arrays, simplifying production compared to conventional multi-step lithography processes.
Key parameters such as voltage, electrode geometry, and microstructure height were optimized to ensure reliable droplet actuation. The device supported standard digital microfluidic operations—including droplet transport, splitting, and merging—on both flat and 3D surfaces. Cell suspensions could be precisely guided into the chip’s micro-wells.
Once inside these structures, cells self-assembled into compact spheroids that exhibited enhanced interactions and organization similar to tissue found in living organisms. Viability tests confirmed that cells remained healthy over several days, while imaging showed dense multicellular architectures resembling those seen in vivo.
The researchers stated: "Integrating 3D microstructures directly into a digital microfluidic chip addresses a long-standing bottleneck in microfluidic cell culture." They added that their platform "combines precise droplet control with a biologically relevant 3D environment, while avoiding complex fabrication workflows." According to the team: "This balance between simplicity and functionality could help bring advanced 3D cell culture tools into broader use, particularly in laboratories that lack access to specialized microfabrication facilities."
Potential applications for this technology include drug screening—where realistic models can improve predictions of efficacy and toxicity—as well as cancer biology research, tissue engineering, and organ-on-chip development. The researchers plan future improvements such as lowering operating voltages and integrating sensing or multi-cell co-culture features to enable longer-term studies and more complex tissue models.
