English: Based on the bioreceptor, biosensors are classified as enzymatic biosensors (most common biosensor class), immunosensors (possess high specificity and sensitivity and are specifically useful in diagnosis), aptamer or nucleic acid-based biosensors (possess high specificity for microbial strains and nucleic acid-containing analyte), and microbial or whole-cell biosensors. The second classification is made on the basis of the transducer and sensors are categorized as electrochemical (which is further grouped as potentiometric, amperometric, impedance and conductometric), electronic biosensor, thermal biosensor, optical, and mass-based or gravimetric. Another classification includes bioreceptor-analyte combinations, which are limited. Some classifications are made depending on the detection system (optical, electrical, electronic, thermal, mechanical, and magnetic) and the technology (nano, surface plasmon resonance (SPR), biosensors-on-chip (lab-on-chip), electrometers, and deployable).