Scientists at the University of Minnesota have developed a method to detect misfolded proteins more rapidly and sensitively. The technique could eventually allow clinicians to diagnose diseases that involve misfolded proteins more easily, including Alzheimer’s, Parkinson’s, and Creutzfeldt-Jakob disease. The approach involves an enhancement to an existing assay called Real-Time Quaking-Induced Conversion (RT-QuIC) assay. This assay involves adding a small sample containing misfolded proteins to a larger protein sample, and shaking the mixture for hours. This causes the misfolded proteins to increase in number, allowing their eventual detection. These researchers discovered that adding 50-nanometer silica nanoparticles to the mixture drastically increased the speed of the assay from 14 hours to approximately 4 hours, permitting lab technicians to potentially run multiple rounds of diagnostic assays each day.
Neurodegenerative diseases can involve the presence of misfolded proteins in the central nervous system. A reliable and rapid way to detect these proteins would be highly beneficial, but methods such as immunohistochemistry and enzyme-linked immunosorbent assays can be time-consuming and expensive, and the antibodies used in such assays may struggle to detect misfolded proteins specifically.
A more advanced approach is the RT-QuIC assay, which involves shaking the sample potentially containing the misfolded proteins with a larger sample of normal proteins. This causes the protein misfolding to spread throughout the sample, resulting in a larger sample of misfolded proteins to detect. However, this process is not rapid, taking as long as 14 hours, and making it difficult for lab technicians to even get it completed in one working day.
Happily, these University of Minnesota researchers have found a relatively simple way to enhance both the speed and sensitivity of the RT-QuIC assay. This involves including 50-nanometer silica nanoparticles in the reaction mixture. This not only decreased the reaction time to approximately four hours but also enhanced the sensitivity of the assay by ten-fold. The new assay, called Nano-QuIC (Nanoparticle-enhanced Quaking-Induced Conversion), also produced no false positive results in tests, highlighting its reliability.
“This paper mainly focuses on chronic wasting disease in deer, but ultimately our goal is to expand the technology for a broad spectrum of neurodegenerative diseases, Alzheimer’s and Parkinson’s being the two main targets,” said Sang-Hyun Oh, a researcher involved in the study. “Our vision is to develop ultra-sensitive, powerful diagnostic techniques for a variety of neurodegenerative diseases so that we can detect biomarkers early on, perhaps allowing more time for the deployment of therapeutic agents that can slow down the disease progression. We want to help improve the lives of millions of people affected by neurodegenerative diseases.”
Study in journal Nano Letters: Nanoparticle-Enhanced RT-QuIC (Nano-QuIC) Diagnostic Assay for Misfolded Proteins