Question

Many drugs under development are delivered by nanoparticles in the bloodstream. To monitor changes in the nanoparticles, investigators can retrieve them from the blood by using a device with electrodes that apply oscillating electric fields. The nanoparticles, which are electrically conducting, are strongly attracted to the nearest electrode, while blood cells, which are poor conductors, experience only a weak force toward the nearest electrode, and suspended ions in the blood experience no net force. Explain why the conducting nanoparticles are strongly attracted to the electrodes while other components of the blood are not.

Answer 1

Answer:

This is because the technology relies on designing a chip that can work in the high salt concentration of blood plasma. The chip’s ability to pull the nanoparticles out of plasma is based on differences in the material properties between the nanoparticles and plasma components. When the chip’s electrodes apply an oscillating electric field, the positive and negative charges inside the nanoparticles reorient themselves at a different speed than the charges in the surrounding plasma. This momentary imbalance in the charges creates an attractive force between the nanoparticles and the electrodes. As the electric field oscillates, the nanoparticles are continually pulled towards the electrodes, leaving the rest of the plasma behind. Also, the electric field is designed to oscillate at just the right frequency: 15,000 times per second.

Explanation:

Read more about nanoparticles here;

https://www.iflscience.com/health-and-medicine/researchers-use-electrical-field-remove-nanoparticles-human-blood/

The plasma is placed into contact with platinum electrodes covered in a hydrogel layer. An alternating electrical current is generated, which temporarily causes the positive and negative changes within the nanoparticles to become imbalanced. This means that the nanoparticles are now attracted towards the electrodes; they travel towards them, while leaving the blood plasma components behind. The plasma is then washed out of the environment.

This attractive force effect – called dielectrophoresis – is not quite the same as electromagnetism. It is only possible because the nanoparticles in this case are made of non-magnetic materials that respond to this type of alternating electrical current, meaning that some types of nanoparticles won’t be able to be retrieved in this way. However, the device used to generate the current is in itself a breakthrough: It is roughly the size of a dime, and can withstand the extremely high salt concentrations present in blood plasma. Most significantly, its actions leaves the plasma completely intact.