Blood, air and water are not only most abundant but also the most important fluids on the earth. Each adult human carries almost a gallon of blood every moment. This paper concerns with the treatment of the blood and discusses in particular the blood cell separation (fluids engineering) and the safe elevation of the body temperature (thermal engineering). Unlike air and water the blood is a biological fluid. Therefore it comes with the complexity of blood composition and disorder of the blood affecting human life and health. This study presents applications of electro-magnetic field on nanomagnetic particles that attach to the blood cells in creating complex fluid dynamic cell separation from the whole blood and creating complex thermal heating, magnetic hyperthermia, for potential use in cancer treatment. In general, biological cells are weak paramagnetic or diamagnetic. Therefore nano-microtechnologies are developed to attach the nanoparticles to the selected cells and to enhance the magnetic susceptibility of the cells to interact with an applied magnetic field. The paper demonstrates that nano to micron size magnetic particles are tagged to the biological cells.