Electrochemical immunosensors: Critical survey of different architectures and transduction strategies

• Different types of electrochemical immunosensors are described.
• Their inherent advantages and limitations in analysis are discussed.
• Signal amplification strategies are discussed.
• Adaptability to multiplexed formats, fluidics and paper-based approaches is discussed.
• Perspectives in POC analysis and commercialization opportunities are discussed.

This review describes the most popular architectures and transduction strategies that have been proposed for the development of electrochemical immunosensors. Relative published work has been classified into four main categories: i) enzyme-labelled immunosensors, ii) metal nanoparticle- and quantum dot-labelled immunosensors, iii) capacitive and (faradic) impedimetric immunosensors, and iv) magnetoimmunosensors. The principle of operation, analytical features, various signal amplification strategies as well as the adaptability of the afore-mentioned types of immunosensors to multiplexed formats, (micro) fluidic platforms and paper-based approaches are critically discussed. Perspectives in point-of-care analysis and commercialization opportunities are also discussed.