This paper describes a novel technology - an electric field isolator (EFI) - that can be used for achieving isolated and electrophoretic manipulation of charged biomolecules inside a selected microscopic location. The EFI is a ground ring-shaped electrode ( RE) surrounding a centre electrode (CE), which is comprised of a functional unit. When the CE is powered, the ground RE can inhibit the electric field from spreading to the neighbouring functional units. Therefore, the electrophoretic movement of the charged molecules in an electric field, which is based on the principle similar to that of electrophoresis, can be isolated inside a selected location. The ground RE causing this phenomenon is referred to as the EFI. In this paper, we clearly show the functionality of the EFI with mathematical and experimental studies.