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

Abstract

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.

Keywords: Ag nanoparticle; Au nanoparticle; Pt nanoparticle; biosynthesis; collision; single nanoparticle.

Figure 1

UV–visible spectra of (a) Au NPs and (b) Ag NPs synthesized using SMFE.

Figure 2

Transmission electron microscopy (TEM) images, size distribution and DLS measurement of (a) Pt NPs, (b) Au NPs and (c) Ag NPs synthesized using the SMFE.

Figure 3

Cyclic voltammogram of hydrazine oxidation at (a) Au UME and Pt UME, (b) C-Fiber UME and Au UME, and (c) Ag UME and Au UME in 50 mM phosphate buffer (PBS) (pH 7.4) containing 15 mM hydrazine at 50 mV/s of scan rate.

Figure 4

CA curves for single Pt NPs collisions at the Au UME in pH 7.4 buffer solution (15 mM hydrazine) containing various concentrations of Pt NPs (i) 0, (ii) 0.86, (iii) 1.70, (iv) 2.60, and (v) 3.40 nM at 0 V of applied potential. Data acquisition time is 50 ms.

Figure 5

CA curves for single Au NPs collisions at the C-Fiber UME in pH 7.4 buffer solution (15 mM hydrazine) containing various concentrations of Au NPs (i) 0, (ii) 0.011, (iii) 0.023, (iv) 0.034, and (v) 0.045 pM at an applied potential of 0.25 V. Data acquisition time is 50 ms.

Figure 6

CA curves for single Ag NPs collisions at the Au UME in pH 7.4 buffer solution (15 mM hydrazine) containing various concentrations of Ag NPs (i) 0, (ii) 1.80, (iii) 3.60, (iv) 5.40, and (v) 7.20 pM at an applied potential of 0.7 V. Data acquisition time is 50 ms.