Nanomaterials in Label-free Impedimetric Biosensor: Current Process and Future Perspectives

Today, the application of nanomaterials has been gaining prominence in the field of biosensing technologies as it offers more and more impact studies to improve the sensitivity, specificity, speed of response and cost effectiveness. Especially in electrochemical impedance spectroscopy technique, an outstanding electrical biotransducer, nanomaterials have been extensively used in almost all studies over the past decade. The nanostructures used in the construction of sensing devices vary in size, shape and physicochemical properties, such as nanoparticles, nanotubes, nanosheets, nanoelectrodes or nanochannels. The use of nanomaterials in impedimetric biosensor involves two key principles: (1) to develop a new sensing substrate via surface modification techniques with the aim of increasing the impedimetric response and (2) to develop a compatible sensing platform to facilitate the detection based on the resemblance in size between targets and signal transducers. Herein, the review shows the recent trends of using engineered nanomaterials in impedimetric biosensors as a factor of signal amplification. The detection events are diverse from biomolecular recognitions including enzymes, proteins, nucleic acids, etc. to whole cells monitoring. Additionally, the shortcomings of current techniques and future perspectives of impedimetric point-of-care devices are also included.