A Concise Review of the Control and Assessment of Magnetic Affinity Particle Assembly for Live Cell Analyses: State of the Art and Challenges.

Magnetic particles have gained prominence in biomedical analyses due to their unique properties, originating from the high surface area-to-volume ratio, ease of functionalization, and their ability to respond to an external magnetic field. Despite its impact in affinity-based biosensing, magnetic particle cluster formation is a largely underrepresented topic at the border of materials sciences, engineering, and biology. This mini-review examines the recent literature demonstrating novel assays based on the assembly of magnetic affinity particles and target live cells, fostering biomedical analyses. It highlights the biosensing opportunities of lab-on-a-chip characterization methods for immunomagnetic clusters and novel approaches for improving affinity capture. It critically discusses the specific means for the on-off control of particle-based immune clusters towards rapid, quantitative tools in live cell detection and analysis of their relevance for biomedical applications involving rare cells in patient samples, such as circulating tumor cells (CTC) and sepsis-related microorganisms. The review aims at encouraging research in magnetic affinity clustering control for biosensing and provides an inter-disciplinary perspective on this high-impact field.