Toward Lab-In-Fiber Liquid Biopsy: Graphene-Oxide Functionalized Anti-Resonant Optical Fiber for Single-Device...

Metastatic spread in aggressive cancers is often initiated by circulating tumor cells (CTCs) before primary tumor detection. Current CTC analysis faces fundamental limitations due to extreme cell scarcity (≈10 cells mL^-1 blood) and reliance on large sample volumes (>7.5 mL). To address these challenges, an integrated graphene oxide-functionalized hollow-core anti-resonant fiber (HARF-GO) platform is developed that combines: 1) enhanced photon-matter interactions through optical confinement, enabling 700-fold signal amplification compared to microplate assays without requiring external photonic components, and 2) intrinsic microfluidic capabilities for continuous processing of microliter-scale samples. This "lab-in-fiber" system achieves exceptional sensitivity (2 CTCs/assay) using <1 mL serum within 1 h - performance parameters that fully meet clinical CTC analysis requirements. Notably, captured cells maintain 94% viability after gentle elution with high-ionic-strength buffer, enabling robust downstream molecular analysis. By seamlessly integrating cell capture, enrichment, optical detection, and viable cell recovery in a single device, the technology overcomes critical limitations of current liquid biopsy methods, providing new capabilities for both minimal residual disease monitoring and precision oncology applications.