(E-186) Detection of Cobalt Ions in Aqueous Solution for Health Applications

Introduction:: As per the Mayo Clinic, about 7.2 million individuals had undergone knee or hip replacements in 2014, and this number has been increasing steadily over the years.¹ Harvard Health reports that nearly 1 million Americans alone receive knee or hip replacements every year.² While such replacements can help relieve mobility issues and pain,³ they may also lead to new problems such as the release of metal ions into the body and a foreign body response.⁴ Metal ions can cause issues such as extreme weight loss, cardiac damage, thyroid damage, and harm to neurological function.^4,5 Presently, there are no efficient and rapid techniques available to monitor these ion levels over time since the existing method involves blood draws and lab-based instrumentation, which are not easily accessible.


Materials and Methods:: Materials required include cobalt chloride hexahydrate, diethylenetriamine pentaacetate (DTPA), a plate reader/ spectrophotometer, and deionized water. The cobalt salt is added to deionized water. Once the solution is well mixed, diethylenetriamine pentaacetate is added to cause the cobalt to fall out of solution. This causes a color change that is detectable using a spectrometer.


Results, Conclusions, and Discussions:: In Figure 1, we can see that there is a clear difference in the absorbance value around 510 nm between the urine with a known concentration of cobalt and the urine with a known concentration of cobalt + DTPA. This means we will be able to use DTPA as a binding agent to determine the amount of cobalt in urine. This may be extended to calculated the concentration of cobalt in other aqueous biofluids (e.g., saliva, sweat). Joint replacements and related issues affect millions of Americans every year. Developing a rapid and accurate method for detecting metal ions in urine could significantly enhance patient outcomes by enabling healthcare providers to monitor implant conditions consistently and non-invasively.

Moreover, this new assay could be applied to other use cases such as detecting heavy metals in water at problematic sites like Flint, Michigan in 2014; Jackson, Mississippi in 2021; and Hoosick Falls, New York in 2016. Thus, the device can provide individuals worldwide with an opportunity to test the safety of their drinking water. The future of this project and ultimate goal is to create a portable device to quickly determine the cobalt concentration in aqueous solution in the field or at the point of care. This will ultimately determine the amount of cobalt ions in the urine or drinking water and enable more rapid responses to address issues.


Acknowledgements (Optional): : Funding was provided by Clemson University’s Creative Inquiry Program and a VentureWell program grant.


References (Optional): : 1. “Orthopedic Surgery.” Mayo Clinic, Mayo Foundation for Medical Education and Research, https://www.mayoclinic.org/medical-professionals/orthopedic-surgery/news/first-nationwide-prevalence-study-of-hip-and-knee-arthroplasty-shows-7-2-million-americans-living-with-implants/mac-20431170.6

2. Robert H. Shmerling, MD. “How Long Will My Hip or Knee Replacement Last?” Harvard Health, 2021, https://www.health.harvard.edu/blog/how-long-will-my-hip-or-knee-replacement-last-2018071914272.7

3. Maradit Kremers, Hilal, et al. “Prevalence of Total Hip and Knee Replacement in the United States.” The Journal of Bone and Joint Surgery. 2015

4. K. Pelclova, et al. “Severe Cobalt Intoxication Following Hip Replacement” Clinical Toxicology (Philadelphia, Pa.), 2012.

5. Rehman K., et al., “Prevalence of Exposure of Heavy Metals…” Journal of Cellular Biochemistry, 2018