The advancement of liquid biopsy techniques promises to revolutionize cancer diagnostics and therapy monitoring, by offering a minimally invasive approach to track tumor progression and treatment efficacy. One central issue preventing advancements are innovations in sensor technology, necessary to enable the detection of molecular and cellular biomarkers with sufficient precision. Over the past decade, atomic-scale quantum sensors have emerged as powerful detectors, offering the ability to perform precise measurements of temperature, pressure, and magnetic fields on the single cell scale. These sensors, based on the interaction of spin qubits with their environment, have the unique capability to amplify and exploit environmental interactions for highly accurate detection, making them ideal for complex biological applications. In this context, we present an advanced quantum sensing platform specifically tailored for liquid biopsy applications in cancer therapy monitoring. This platform integrates the capabilities of optical microscopy with magnetic resonance imaging (MRI) techniques, utilizing nitrogen-vacancy (NV) centers in diamond as quantum sensors by converting magnetic resonance signals into optical signals, which are subsequently captured by a high-speed camera. Our platform offers a novel approach, promising quantitative analysis of single cancer cells from liquid samples with unprecedented accuracy. Unlike traditional MRI, our method captures signals over a wide field of view directly in real space. Each camera pixel records a magnetic resonance spectrum, providing detailed multicomponent information about the sample, such as molecular concentration, diffusion, and relaxation behavior, which are critical for understanding the tumor’s microenvironment. Our quantum sensing technology holds significant potential for enhancing the sensitivity of liquid biopsies. By capturing detailed molecular information from blood or other body fluids, it will enable in-depth analysis of Circulating Tumor Cells (CTCs), circulating tumor DNA (ctDNA), exosomes, and other biomarkers.

Citation Format: Karl D. Briegel, Robin D. Allert, Dominik B. Bucher, Julia D. Draeger, Nick R v. Grafenstein, Linyan Nie. Towards magnetic resonance microscopy for liquid biopsy in cancer therapy monitoring [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B033.