In this work, a simple, selective and stable strategy for encapsulation of triangular ruthenium nanoplates (RuNPs) through o-Phenylenediamine (oPD) polymerization on graphene modified screen-printed carbon electrode (SPEGPH) was demonstrated. o-Phenylenediamine polymer (PoPD) film provided a suitable microenvironment for RuNPs immobilization. Synthesis of RuNPs was characterized by transmission electron microscope (TEM) and electrochemical methods including cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Encapsulation or incorporation of RuNPs through PoPD were carried out following three different strategies and the resulting platforms were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The electrocatalytic performance of RuNPs-PoPD-GPH platform was demonstrated using the NADH oxidation as model electrochemical reaction. The incorporation of 18 +/- 3 nm RuNPs onto PoPD decreased the NADH oxidation potential by ca. 350 +/- 5 mV in comparison to bare SPEGPH as well as a remarkable enhance of sensitivity to NADH detection. Therefore, RuNPs have provided electron transfer with a strong catalytic effect for NADH oxidation representing a promising application in sensors. (C) 2019 Elsevier Ltd. All rights reserved.