MagnetoCrisprZyme sensor for quantification of circulating microRNA in primary care settings

Background Breast cancer is the most common cancer in the UK, with about 1 in every 8 women being diagnosed this disease during their lifetime. Current screening and follow-up technologies, but also next-generation tools currently approaching the clinic (e.g.

GRAIL technology), can synergistically benefit from liquid biopsies performed at the point-of-care (e.g. at a GP practice).

Point-of-care (POC) diagnostics could allow a paradigm shift in the way screening and monitoring are currently performed, complementing centralized tests, improving patient monitoring and providing personalized biomarkers baselines. Circulating micro RNAs (cmiRNA) represent a promising source of biomarkers for breast cancer detection.

Current techniques employed for the quantitative detection of cmiRNA all require specialized equipment and trained personnel, due to complexity in isolating nucleic acids, performing the analysis and interpreting the outcomes.

These disadvantages lead to high costs and requirement for centralized facilities, preventing the deployment of these tests at the POC.

Aims In this project we aim at developing a POC-compatible nanosensor for the detection of breast cancer-specific cmiRNA with minimal operational burden, in a manner that can be readily scaled at affordable costs, eventually enabling the use of the developed sensor in primary care settings, complementing centralized tests by enabling frequent testing towards personalized biomarkers monitoring.

Methods Building on Prof Stevens' experience in the development of ultrasensitive POC sensors, we will employ nanotechnology and bioconjugation techniques to develop a POC diagnostic test with performance comparable to benchtop analyzers.

The first component of the test will be magnetic nanoparticles functionalized with Cas enzymes: these will act as "selective sponges", capturing and pre-concentrating target cmiRNA directly from patient sample (simplifying the requirements for sample isolation and removing the need for enzymatic sample pre-amplification).

After sample capture and concentration, we will combine a cas-mediated cleavage reaction (triggered by the capture of the target RNA) with a nanozyme-powered lateral flow immunoassay, enabling simple, colorimetric detection of the target cmiRNA.

How the results of this research will be used Within this project, we will focus on demonstrating the feasibility of our platform in detecting miR-21 in breast cancer patients samples.

The proof-of-concept data generated will then support follow-up grants aiming at detecting larger panels of circulating RNAs associated to early detection of breast cancer relapse using the platform here developed, and assessing the scalability of the sensor.