Cancer diagnosis and longitudinal monitoring increasingly depend on biosensing technologies capable of detecting low-abundance, heterogeneous, and dynamic biomarkers in complex biological samples. Hydrogel-based biosensors offer a distinctive materials platform for this purpose because their hydrated, porous, tunable, and biomolecule-compatible networks can integrate molecular recognition, antifouling protection, nanomaterial-assisted signal amplification, and three-dimensional biological interfaces within a single sensing architecture. Across cancer-focused applications, hydrogels have been engineered to detect nucleic acids, soluble protein markers, tumor-associated enzymes, extracellular vesicles, circulating tumor cells, metabolic products, redox signals, and tumor microenvironmental cues in matrices such as serum, plasma, saliva, urine, sweat, blood, cell lysates, and three-dimensional cancer models. Their functional value extends beyond passive immobilization: hydrogels can serve as programmable recognition networks, gated reservoirs, conductive interfaces, optical and plasmonic scaffolds, degradable enzyme-responsive matrices, and cell-compatible microenvironments. These attributes support sensitive biomarker detection, multiplexed profiling, portable and smartphone-assisted formats, wearable or minimally invasive systems, and dynamic monitoring of tumor behavior and treatment response. Nevertheless, the field remains uneven in translational maturity, with many platforms still requiring broader clinical validation, standardized benchmarking, manufacturable device designs, reproducible fabrication, and practical assessment of assay complexity, storage stability, and patient-sample performance. This review positions biomarker-responsive hydrogels as a convergence point between advanced materials engineering and clinically oriented cancer biosensing, with particular promise for liquid biopsy, decentralized diagnostics, and tumor-state-resolved monitoring.
Omidian et al. (Thu,) studied this question.