Tumor Mutational Burden (TMB) is a critical biomarker used to determine patient eligibility for immunotherapy with immune checkpoint inhibitors. However, its gold-standard assessment via whole exome sequencing is limited by high costs, technical complexity, and lengthy processing times. To address these challenges, we investigated whether Ultra-High-Frequency (UHF) electromagnetic wave sensing could serve as an alternative method for evaluating TMB. We analyzed the dielectrophoresis crossover frequency spectrum and corresponding electromagnetic signature (EMS) of cancer cells using a lab-on-a-chip biosensor that integrates microfluidics with dielectrophoresis-based electro-manipulation. Across seven solid tumor cell lines exhibiting diverse TMB levels, EMS exhibited an upward shift correlated with higher TMB, suggesting a relationship between mutational load and electromagnetic behavior. To further explore this connection, we artificially increased the somatic variant burden by exposing cells to the mutagen N-ethyl-N-nitrosourea (ENU). EMS measurements reliably detected the induced increase in variant load in ENU-treated cells. Overall, these findings demonstrate that EMS can detect both intrinsic TMB differences and experimentally induced increases in mutational burden, enabling refined categorization of cancer cells. Although further validation is required, this work lays the foundation for developing complementary, rapid, and accessible tools to support cancer cell stratification and guide immunotherapy decision-making.

Cancer stem-like cells (CSCs) enrichment and characterization remain an analytical challenge, as conventional marker-based approaches are often time-consuming and can alter cellular properties. Here, we develop a complete label-free protocol for the enrichment and characterization of cellular states associated to stemness properties in colorectal cancer model, based on the coupling adjustment of sedimentation field-flow fractionation (SdFFF) and ultra-high-frequency dielectrophoresis (UHF-DEP). To this end, the operating conditions of SdFFF were adapted to a low conductivity dielectrophoresis buffer while maintaining the hyperlayer elution regime. Fractionated cellular subpopulation exhibits phenotypic differences in proliferative status, clonogenic potential, stem-cell related protein levels and UHF-DEP highlights significantly different high-frequency crossover distributions. Transcriptome sequencing revealed dysregulation of pathways associated with stemness, cell adhesion, membrane organization, calcium signaling and ion-channel activity, that can be linked to dielectric signatures. Overall, UHF-DEP coupling to SdFFF permit to enrich, characterize and quantify stem cell-like subpopulation within heterogeneous population of cancer cells.