**4. Types of nanoparticles used in electrosensing**

A nanoparticle has diameter approximately one lakh times smaller than that of a human hair strand. Nanomaterials, like in many other technological or scientific segments, have demonstrated their applicability and worthiness for electrochemical/biosensing applications. The astute use of such nanomaterials has resulted in clearly improved performance, with enhanced specificity, sensitivity, and extremely lowered limits of detection. Further, the high specific surface area of all nanoobjects allows for the immobilisation of an increased number of bioreceptor units (in biosensors) [37]. The direct functionalisation of nanomaterials (during their synthesis) or coating of nanomaterials with specific functional polymers results in nanomaterials equipped with desired functions without altering their specific properties [38]. The commonly used nanoparticles in electrosensing applications are of following types:

