fig1

Figure 1. Electrochemical biosensor technologies based on different sensing principles. (A) Amperometric detection of metabolites using enzyme-functionalized electrodes; (B) Voltammetric sensing of proteins or nucleic acids via electrodes modified with antibodies or oligonucleotides. Detection strategies include multistep sandwich formats, binding-induced conformational switches, or proximity-based affinity recognition; (C) Representative architectures of ion-selective electrodes for potentiometric biosensing; (D) Conceptual illustration of conductometric sensing, where changes in electrical conductivity upon target interaction are used for analyte quantification. Reproduced with permission^[44]. Copyright 2022, MDPI; (E) Impedimetric biosensing of analytes at varying concentrations, with Nyquist plots illustrating the system’s electrochemical behavior. The inset shows the randles equivalent circuit, comprising R_s, R_ct, C_dl, and W. Reproduced with permission^[45]. Copyright 2014, American Society for Microbiology. WE: Working electrode; AC: alternating current; R_s: solution resistance; R_ct: charge-transfer resistance; C_dl: double-layer capacitance; W: Warburg impedance.