In this study, Silver-Platinum (Pt-Ag) bimetallic nanoparticles were synthesized by the biogenic reduction method using plant extracts. This reduction method offers a highly innovative model for obtaining nanostructures using fewer chemicals. According to this method, a structure with an ideal size of 2.31 nm was obtained according to the Transmission Electron Microscopy (TEM) result. The Pt-Ag bimetallic nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), and Ultraviolet-Visible (UV-VIS) spectroscopy. For the electrochemical activity of the obtained nanoparticles in the dopamine sensor, electrochemical measurements were made with the Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) methods. According to the results of the CV measurements taken, the limit of detection (LOD) was 0.03 µM and the limit of quantification (LOQ) was 0.11 µM. To investigate the antibacterial properties of the obtained Pt-Ag NPs, their antibacterial effects onEscherichia coli(E. coli) andStaphylococcus aureus(S. aureus) bacteria were investigated. In this study, it was observed that Pt-Ag NPs, which were successfully synthesized by biogenic synthesis using plant extract, exhibited high electrocatalytic performance and good antibacterial properties in the determination of dopamine (DA).