biosensor

Biosensors are analytical devices that combine a biological recognition element with a transducer to detect a target and generate a signal that can be measured and analyzed. They convert a biological interaction into a quantitative or semi-quantitative readout, enabling rapid, on-site measurements with minimal sample preparation.

Components typically include a biorecognition element, such as an enzyme, antibody, nucleic acid, or whole cell, which selectively binds or reacts with the analyte; a transducer that converts the interaction into an electrical, optical, or mass-based signal; and a signal processing system that displays or records the result.

Principle of operation involves the target interaction producing a detectable change—electrical current, voltage, impedance, light, or mass—that the transducer converts into a measurable signal proportional to the analyte concentration. Calibration and appropriate controls are used to interpret results.

Transduction types encompass electrochemical (amperometric, potentiometric, conductometric), optical (colorimetric, fluorescence, luminescence, surface plasmon resonance), and mass-sensitive approaches (piezoelectric, quartz crystal microbalance). Common recognition elements include enzymes (for example, glucose oxidase), antibodies, aptamers, nucleic acids, and whole cells.

Applications span medical diagnostics (such as glucose monitoring and infectious disease detection), environmental monitoring for pollutants, food safety testing, and industrial process control. Benefits include speed, small size, low sample volumes, and potential for point-of-care use; challenges include stability, fouling, selectivity, drift, and production costs.

Ongoing research aims to integrate biosensors with microfluidics and nanomaterials, pursue label-free and multiplexed sensing, and develop wearable or wireless platforms for continuous monitoring.