Recent progress in nanoscale optical sensor technologies for early cancer detection and diagnosis

Abstract Timely and accurate diagnosis of cancer is critical for enhancing patient survival. Nevertheless, traditional diagnostic methods, such as medical imaging, histopathology, and molecular analyses, are usually invasive, time-consuming, and insufficiently sensitive at an early disease stage. Optical biosensor technologies are therefore considered potential alternatives in this context because of their capability to offer fast, label-free, and high-sensitivity detection of cancer biomarkers. In this review, we present the recent developments in major optical biosensing platforms, including surface plasmon resonance (SPR), fluorescence-based sensing, Raman and surface-enhanced Raman scattering (SERS), optical fiber, photonic crystal, and interferometric sensors. The use of functional nanomaterials to improve the detection of clinically relevant biomarkers, including proteins, circulating tumor cells, circulating tumor DNA, microRNAs, and exosomes, is addressed: gold and silver nanoparticles, graphene, quantum dots, and metal oxides. In addition, novel sensor architectures, including lab-on-a-chip, wearable, and implantable devices, and AI-assisted analytical strategies have been explored in the context of their applicability in precision oncology. Essential issues related to biocompatibility, scalability, and regulatory translation are also discussed. In general, it is possible to note that this review indicates that optical biosensor technologies have increasing potential to help facilitate reliable, early, and clinically translatable cancer diagnostics.