Circulating tumor cells: Biosensors in precision oncology

The detection and analysis of circulating tumor cells (CTCs) have emerged as a crucial aspect of precision oncology, offering insights into tumor dynamics, treatment response, and metastatic potential. This review explores innovative biosensing technologies designed for the sensitive and specific identification of CTCs in the bloodstream. We discuss various biosensor platforms, including optical, electrochemical, and microfluidic systems, emphasizing their mechanisms, performance, and clinical applications. By integrating advancements in nanotechnology and biomolecular engineering, these biosensors have significantly enhanced CTC capture and characterization, facilitating personalized therapeutic strategies. Importantly, the role of CTCs extends beyond diagnostic capabilities; they also serve as valuable tools in drug delivery systems. CTCs can be engineered to enhance the targeted delivery of therapeutics, providing a means for chemotherapy and immunotherapy to be more directly focused on tumor sites, thereby improving efficacy and reducing systemic toxicity. This dual function of CTCs underscores their significance in the development of innovative cancer therapies. Furthermore, we address the challenges and future directions in biosensor development, including the need for automation, real-time monitoring, and multimodal approaches. Ultimately, this work highlights the transformative potential of biosensors in advancing precision oncology, providing a pathway toward improved patient outcomes through tailored cancer therapies.