University of Wisconsin-Stout faculty have patented a new chemical probe to detect citrulline, an amino acid linked to autoimmune diseases and cancer.

Biochemistry professor Jennifer Grant and chemistry professor Dmitry Kadnikov of the University of Wisconsin-Stout Polytechnic have been granted a U.S. patent for a new method to detect citrulline. The amino acid is a known indicator of multiple sclerosis, rheumatoid arthritis, various neurological disorders, and cancer. The development follows more than a decade of collaborative research involving the two professors and numerous student researchers.

Overcoming Detection Challenges

Citrulline has historically been difficult to detect because the modification creating it adds only the weight of a single hydrogen atom to a protein. Previous chemical probes used for this purpose were often costly and cumbersome, leading many researchers to avoid the subject. Grant began exploring a more efficient process after observing the limitations of existing methods during her postdoctoral work 20 years ago.

A Two-Step Detection Process

The patented method functions in two distinct steps. First, a sensitive chemical probe attaches to the citrulline. Second, a chemical tag is added to the probe to facilitate detection. This tag is modular and can be customized based on a researcher's specific needs, such as using an antigen, a nanoparticle, or a fluorescent tag for imaging. Grant described the flexibility of the process as being similar to a factory using interchangeable parts.

Research and Development Timeline

The research team included several UW-Stout Polytechnic students, with alumni Dylan Meyer and Justin Olson co-authoring a 2017 paper in the journal Computational Biology and Chemistry that identified specific protein sites converted to citrulline. The formal patent application process began in 2020, with the patent being published in 2022 before receiving final approval this year.