Continuous Glucose Monitor (CGM) Sensor Fabrication

CGM sensor fabrication represents a technological leap from disposable test strips, requiring sensors to function accurately within the body for weeks. Key fabrication pillars include:

1. Geometry: A split between Planar (screen-printed on flexible polymer, e.g., Abbott) and Wire-based (Pt-Ir wire with dip-coatings, e.g., Dexcom) architectures.

2. Chemistry: The shift from oxygen-dependent 1st-gen sensors to "Wired Enzyme" technology (Osmium redox polymers) allows for operation in hypoxic subcutaneous tissue and eliminates oxygen interference.

3. Membrane Engineering: The application of multi-layer membranes is critical. These layers limit glucose flux to ensure linearity, block electrochemical interferents (like acetaminophen), and mitigate the Foreign Body Response to maintain sensitivity over time.

4. Factory Calibration: Advances in manufacturing precision have eliminated the need for user fingerstick calibration by ensuring uniform membrane thickness and electrode surface area across batches.