Magnetic Nanoparticles for the Microfluidic Separation of Pathogens from Blood


The use of magnetic nanoparticles for the separation of pathogens from blood offers a novel treatment for bacterial sepsis. The technology is suited to accommodate a variety of liquids (buffers, albumin, beverages, etc.), thus extending possible applications.

Problem Addressed

Bacteremia—the presence of bacteria in the bloodstream—is most often resolved by the host immune system. However, if left unchecked, bacteremia can lead to serious complications including sepsis, a highly lethal systemic response often triggered by the release of endotoxins from bacteria. Common treatments for sepsis include antibiotics, intravenous fluids, and vasoactive medications to increase blood flow to major organs. However, the mortality rate of sepsis (28-50%) remains quite high. The use of functionalized nanoparticles to rapidly and selectively bind and separate pathogens from blood is a novel and efficient alternative to conventional sepsis treatments.


Magnetic nanoparticles are composed of a core magnetic material (e.g., iron oxide) attached via a polymer spacer (e.g., polyethylene glycol) to ligands that are capable of binding specific pathogens. Ligands include zinc-coordinated bis(dipicolylamine) (bis-Zn-DPA), which selectively and rapidly (within five minutes) binds Gram-negative and Gram-positive bacteria in addition to endotoxins. The mixture is injected into a microfluidic system in which magnets along the flow path attract the nanoparticles that are bound to contaminants, thus restricting their flow to the outlet. The system achieves a near complete removal of bacteria from blood with a shorter incubation time and at a higher flow rate than existing methods. 


  • Generic separation technique can be used on many target contaminants
  • Highly selective separation—nanoparticles do not bind mammalian cells
  • Rapid incubation and separation—minimizes the time blood spends outside the body, reducing risk of coagulation and contamination
  • Synthetic ligands are stable, inexpensive, and straightforward to synthesize
  • Compatible with existing clinical blood-modifying technologies (e.g., hemodialysis)