Microfluidic Quaking-Induced Conversion (Micro-QuIC) for Rapid On-Site Amplification and Detection of Misfolded Proteins

Abstract

Protein misfolding diseases, such as prion diseases, Alzheimer's, and Parkinson's, share a common molecular mechanism involving the misfolding and aggregation of specific proteins. There is an urgent need for point-of-care (POC) diagnostic technologies that can accurately detect these misfolded proteins, facilitating early diagnosis and intervention. Here, we introduce the Microfluidic Quaking Induced Conversion (Micro-QuIC), a novel acoustofluidic platform for the rapid and sensitive detection of protein misfolding diseases. We demonstrate the utility of our technology using chronic wasting disease (CWD) as a model system, as samples from wild white-tailed deer are readily accessible, and CWD shares similarities with human protein misfolding diseases. Acoustofluidic mixing enables homogeneous mixing of reagents in a high-Reynolds-number regime, significantly accelerating the turnaround time for CWD diagnosis. Our Micro-QuIC assay amplifies prions by an order of magnitude faster than the current gold standard, real-time quaking-induced conversion (RT-QuIC). Furthermore, we integrated Micro-QuIC with a gold nanoparticle-based, naked-eye detection method, which enables visual discrimination between CWD positive and negative samples without the need for a bulky fluorescence detection module. This integration creates a rapid, POC testing platform capable of detecting misfolded proteins associated with a variety of protein misfolding diseases.

Visual detection of misfolded alpha-synuclein and prions via capillary-based quaking-induced conversion assay (Cap-QuIC)

“…Since the Cap-QuIC method leverages simple capillary action, it can be potentially integrated into microfluidic systems to enhance point-of-care technologies for a host of proteinopathies. One such microfluidic system utilizes acoustic agitation to amplify and detect misfolded proteins 53 . The current form of the Cap-QuIC protocol should be done in a BSL-2 setting.…”