In recent years, the fusion of optofluidics with chip-based imaging methods has been the subject of research and development around the world. The ability to isolate analytes in a miniaturized setting, while detecting them with sensors, holds promise for life sciences research and medical diagnostics. But despite the advantage of requiring only trace sample volumes, barriers to this convergence remain. These challenges lie in both materials and system design — for example, how analytes are transported, which affects reading speed, and the use of chip materials with varying levels of absorption. A team of researchers at Vrije Universiteit Brussel (Free University of Brussels), used an optofluidic lab on a chip to obtain absorbance and fluorescence data on protein aggregation, a hallmark of several neurodegenerative diseases. The researchers’ device consisted of a silicon layer sandwiched between two glass layers, featuring a 375-µm internal width, a 32-mm-long microchannel, and a single-mode fiber delivering lasers at wavelengths of 637 nm and 450 nm. Inside the device, the researchers used a fiber-connected collimator to obtain readings of both absorbance and fluorescence. According to the research paper in the Journal of Optical Microsystems (www.doi.org/10.1117/1.JOM.5.1.014004), the readings compared favorably to the accuracy of results from a commercial microplate reader. The team used the system to observe two biological processes: the kinetics of protein aggregation, which is the rate of the formation of molecule clusters, and liquid-liquid phase separation, which is the formation of liquid droplets within an otherwise uniform solution. Heidi Ottevaere, chairwoman of the Applied Physics and Photonics Department at the university, explained that under certain circumstances, these condensates can turn into toxic fibrils. The researchers then used polystyrene beads to mimic absorption and propidium iodide to mimic fluorescence, and measured the protein G3BP1, which Ottevaere said plays a role in stress granule formation in neurodegenerative conditions. Such innovation aligns with this edition’s cover story by Andreu Llobera, who describes organ-on-a-chip (a subset of lab-on-a-chip) technologies applied in cell screening, cell sorting, and molecular diagnostics. These small but versatile devices — including micro-optics, waveguides, and on-chip light sources and detectors — are boosting specificity, sensitivity, accuracy, and the limits of detection. In his article here, Llobera discusses the evolution of materials used in constructing chip-based systems –– from polydimethylsiloxane to various polymers — and the experimentation carried out by companies active in this space. These efforts are expected to propel diagnostics to new frontiers of understanding while reducing reliance on animal-based studies. Enjoy the issue!