Chemical and Technological Aspects of Magnetic Particles for Cancer Liquid Biopsy Applications

Recent progress in molecular diagnostics has been strongly influenced by advances in magnetic bead (MB) chemistry. Synthetic strategies for MB fabrication play a critical role in defining their size, physicochemical properties, and nano- or microscale architectures, which ultimately determine their analytical performance. The efficiency of MBs in liquid biopsy depends on the architecture of their components, including magnetic core, surface functionalization, as well as the integration of recognition ligands. This review highlights the recent developments in MB design for the selective capture, identification, and quantification of cancer biomarkers in liquid biopsy applications. It also summarizes the advantages and limitations of commercially available MB platforms and critically evaluates emerging systems reported in the literature. By comparing current technologies, this review discusses major advances as well as remaining translational bottlenecks, providing guidance for the rational design of next-generation MBs for liquid biopsy. The latter is an emerging technology increasingly used in precision oncology for molecular profiling to support cancer diagnosis, prognosis, and the selection of personalized treatments.