Cancer has been one of the most serious diseases, resulting in more than 10 million deaths every year. Fiber-optic sensors have great potential for diagnosing and treating cancer due to their flexibility, precise positioning, real-time monitoring, and minimally invasive characteristics. Compared to traditional central laboratory examination, fiber-optic biosensors can provide high sensitivity, miniaturization, and versatility, which feature the point-of-care diagnostic capability. Herein, we focus on recent advances in fiber-optic biosensors for cancer theranostics. It is primarily concerned with advancements in the design of various fiber sensing approaches, fiber cancer sensing, and therapy sensors. With fiber-optic biosensors, cancer marker detection, cancerous cell differentiation, ex vivo tumor model validation, and in vivo tumor detection can be achieved. And the medical fiber also can be used to provide photothermal therapy, photodynamic therapy, and combination therapy for solid tumors. Additionally, cancer sensing and therapy can be integrated into the fiber, which demonstrates the multiplexing capabilities of fiber-optic biosensors. Lastly, we systematically summarize the fiber biosensor applications from in vitro to in vivo, and conclude with the challenges in development and prospects.

The illegal water injection into meat not only breaks the market equity, but also deteriorates the meat quality and produces harmful substances. In this work, we proposed a fiber Bragg grating (FBG) sensor that enabled fast, quantitative, and in-situ detection of the moisture content of water-injected meat. The FBG was written in the erbium-ytterbium (Er/Yb) co-doped fiber, which could perform the self-photothermal effect by injecting the near infrared laser into the fiber. As the heated fiber sensor probe was inserted into the meat sample, the temperature decreased due to the heat dissipation mediated by moisture. The intracore Bragg grating could monitor the temperature loss by recording the Bragg wavelength shift, which reflected the water content quantitatively. The results revealed that the sensor could complete the detection within 15s. The sensor’s sensitivity to detect changes in the pork water content was theoretically calculated to be 0.090847%. The proposed sensor is expected to provide a novel approach for examination of the meat moisture.