Magnetic Nanoparticles to Detect Cancer

Printer-friendly versionPDF version

Better known for web searches, Google has recently begun devoting resources to the search for cancer cells as a form of early-stage disease detection. The proposed technology involves an ingestible capsule filled with superparamagnetic iron-oxide nanoparticles (SPIONs) bound to one or multiple antibodies through covalent binding, physical adsorption, or a variety of other methods [1]. The attraction of the antibodies to specific ligands or proteins on the surface of cancerous cells allows for active targeting of diseased cells. Protective patches around the capsules, developed by Google’s collaborator Entrega, would serve to protect the SPIONs and antibodies from the digestive enzymes of the small intestine before they are absorbed through the walls of the intestine. An additional component of the technology includes a magnetized band, which would localize the magnetic nanoparticles to a specific area of the body [2]. Once the antibodies on the nanoparticles detect and bind to the cancer, a new type of MRI developed for nanoparticles called Magnetic Particle Imaging (MPI) would show the extent of the cancer growth. MPI creates positive contrast images in which nanoparticles show up brighter than surrounding tissue (rather than darker), making them easier to see [3]. The positive contrast is created by the reduction of the T1 relaxation time (the time it takes a particle to recover its equilibrium after exposure to a magnetic field) caused by the small molecular weight of the nanoparticles and unpaired electrons in their outer spins [4]. The movement of the nanoparticles during the MPI can also indicate when they have come in contact with cancer, as they will move through the sensor’s magnetic field differently than when unattached to a cell [5]. SPION’s are easier to excrete and safer for patients with Chronic Kidney Disease (CKD) who are unable to use MRIs.

The combined nanoparticles and sensory equipment could allow doctors to become aware of diseases such as cancer at very early stages and take preventative action. This technology is also applicable to viral and bacterial diseases, as antibodies can be engineered to target a wide variety of protein markers [1].

​Artist depiction of the interaction between nanoparticles in the body and magnetic wristband designed to localize nanoparticles.



  1. Montenegro, Jose-Maria, Valeria Grazu, Alyona Sukhanova, Seema Agarwal, Jesus M. De La Fuente, Igor Nabiev, Andreas Greiner, and Wolfgang J. Parak. "Controlled Antibody/(bio-) Conjugation of Inorganic Nanoparticles for Targeted Delivery." Advanced Drug Delivery Reviews 65.5 (2013): 677-88. Web.
  2. Drahl, Carmen. "Google’s Nanoparticle Diagnostic Vision." Chemical and Engineering News, 24 Nov. 2014. Web. 29 May 2015.
  3. Saritas, Emine U., Patrick W. Goodwill, Laura R. Croft, Justin J. Konkle, Kuan Lu, Bo Zheng, and Steven M. Conolly. "Magnetic Particle Imaging (MPI) for NMR and MRI Researchers." Journal of Magnetic Resonance 229 (2013): 116-26. Web.
  4. "MRI Database : Positive Contrast." MRI. Magnetic Resonance - Technology Information Portal, 2003. Web. 29 May 2015.
  5. Kelion, L., & Gallagher, J. (2014). Google is developing cancer and heart attack detector. BBC News Technology
  6. Wells, K., & Hamblin, J. (2015) Why is google making human skin? The Atlantic 



Development Stage: 

Key Words: 


Benefit Summary: 

Compared to an annual screening, SPIONs bound to antibodies create a more accurate, safer method for tracking a patient’s health. With this, Google aims to shift medicine from being about reactive responses to illnesses to being one of constant preventative measure against illness [6].  Such an early reaction time could drastically improve survival rates of cancer patients, given that cancer is much easier to combat in its early stages.         


Risk Summary: 

There are many underlying risks in releasing a foreign substance into the body. The human body naturally attacks any unnatural objects, and Google has not specified how it would prevent toxicity issues. In addition, there also remains the concern of the phenomenon of over-diagnosis as a result of this technology. That is, if slight signs are detected very early, or if they are false positives, then it could lead to treatment that was invasive, unnecessary, and potentially more problematic—an overactive rather than cautions response [5].


Risk Characterization: 

Risk Assessment: