The aim of this paper is to propose an extension of the high-gain observed-based control design obtained in Ahmed-Ali et al. (2023) to the case of sampled-data systems by considering a Zero-Order-Hold (ZOH) device at the input. Moreover the class of nonlinear PDE is also enlarged by adding a nonlinear term in the heat equation. The stability of the overall closed systems is analyzed by using a suitable Lyapunov function.