Combined Blip and Staircase Response of Ascorbic Acid-Stabilized Copper Single Nanoparticle Collision by Electrocatalytic Glucose Oxidation

Electrochemical Detection and Analysis of Various Current Responses of a Single Ag Nanoparticle Collision in an Alkaline Electrolyte Solution

A single silver (Ag) nanoparticle (NP) collision was observed and analyzed in an alkaline solution using the electrocatalytic amplification (EA) method. Previously, the observation of a single Ag NP collision was only possible through limited methods based on a self-oxidation of Ag NPs or a blocking strategy. However, it is difficult to characterize the electrocatalytic activity of Ag NPs at a single NP level using a method based on the self-oxidation of Ag NPs. When using a blocking strategy, size analysis is difficult owing to the edge effect in the current signal. The fast oxidative dissolution of Ag NPs has been a problem for observing the staircase response of a single Ag NP collision signal using the EA method. In alkaline electrolyte conditions, Ag oxides are stable, and the oxidative dissolution of Ag NPs is sluggish. Therefore, in this study, the enhanced magnitude and frequency of the current response for single Ag NP collisions were obtained using the EA method in an alkaline electrolyte solution. The peak height and frequency of single Ag NP collisions were analyzed and compared with the theoretical estimation.

Observation of Single Nanoparticle Collisions with Green Synthesized Pt, Au, and Ag Nanoparticles Using Electrocatalytic Signal Amplification Method

This work describes the tailored design, green synthesis and characterization of noble metal (Pt, Ag and Au) nanoparticles (NPs) using Sapinduss Mukkorossi fruit extract (SMFE) and its signal NP collision signal response, based on the principle of the electrocatatlytic amplication (EA) method. Here, the SMFE can act as both the reducing and the capping agent for the fabrication of noble nanometals. The SMFE-capped NPs was available for the observation of a single NP collision signal. Two general types of current response were observed: a staircase current response for the Pt or Au NPs, and a blip/spike current response for Ag NPs. These results demonstrated that the eco-friendly synthesized SMFE-capped NPs maintained their electrocatalytic activity, therefore they can be used for the single NP experiments and place an arena for future biosensing applications.

Various Current Responses of Single Silver Nanoparticle Collisions on a Gold Ultramicroelectrode Depending on the Collision Conditions

Collisions of silver nanoparticles (NPs) with a more electrocatalytic gold or platinum ultramicroelectrode (UME) surface have been observed by using an electrochemical method. Depending on the applied potential to the UME, the current response to the collision of Ag NPs on the UME resulted in various shape changes. A staircase decrease, a blip decrease, and a blip increase of the hydrazine oxidation current were obtained at an applied potential of 0.33, 0.80, and 1.3 V, respectively. Different collision behaviors of Ag NPs on the UME surface were suggested for each shape of current response. Ag NP attachment, which hindered the diffusion flux to the UME, caused a staircase decrease of the electrocatalytic current. Instantaneous blocking of the hydrazine oxidation by Ag NP collision and, following recovery of the current by means of oxidation of Ag NP, caused a blip decrease of the electrocatalytic current. The formation of a higher oxidation state of Ag on the Ag NP and its electrocatalytic hydrazine oxidation resulted in a blip increase of the electrocatalytic current. The analysis of the current response of a single NP collision experiment can be a useful tool to understand the various behaviors of NPs on the electrode surface.