Microfluidics

Microfluidics is the science of controlling and analyzing small volumes of fluids in networks of microscale channels. Flows at this scale are typically laminar and dominated by viscous and surface forces, enabling precise timing, mixing, and sample handling. The field integrates physics, chemistry, and engineering to create compact devices that perform laboratory tasks on a chip.

Devices and fabrication: Microfluidic devices use substrates such as PDMS, glass, or thermoplastics. Fabrication methods include soft lithography, photolithography, embossing, and injection molding. Core approaches include continuous-flow microfluidics and droplet-based microfluidics, where reactions occur in tiny droplets.

Techniques and operations: On-chip mixing, separation, gradient generation, and droplet generation are common. Digital microfluidics uses electrical fields to move droplets on an array. Applications include point-of-care diagnostics, nucleic acid amplification, high-throughput screening, single-cell analysis, organ-on-a-chip, and chemical synthesis.

Impact and challenges: Microfluidics aims to reduce reagent use, enable portable assays, and integrate workflows. Challenges include clogging, biofouling, device variability, and the need for robust integration with sensors and data systems. The field continues to explore new materials, manufacturing, and hybrid systems with optics and electronics.