Utilization of nanoparticle labels for signal amplification in ultrasensitive electrochemical affinity biosensors: A review

•Basic principle of ultrasensitive electrochemical affinity biosensors for the detection of DNA and proteins.•Applications of nanoparticles for signal amplification in electrochemical affinity biosensors.•Principles of signal amplification strategies involving nanoparticles.•Critical assess the potential drawback associated with each sensing strategy.•Future perspectives for signal simplification in biosensors based on nanoparticles. Nanoparticles with desirable properties not exhibited by the bulk material can be readily synthesized because of rapid technological developments in the fields of materials science and nanotechnology. In particular their highly attractive electrochemical properties and electrocatalytic activity have facilitated achievement of the high level of signal amplification needed for the development of ultrasensitive electrochemical affinity biosensors for the detection of proteins and DNA. This review article explains the basic principles of nanoparticle based electrochemical biosensors, highlights the recent advances in the development of nanoparticle based signal amplification strategies, and provides a critical assessment of the likely drawbacks associated with each strategy. Finally, future perspectives for achieving advanced signal simplification in nanoparticles based biosensors are considered.