Multimodal sensing system based on phenylboric acid-COF/RhB ratio fluorescence: highly sensitive detection of ovarian cancer biomarker, smartphone-assisted field analysis and information encryption and anti-counterfeiting integration.

It is essential to develop an innovative technology with high sensitivity and real-time detection for the early diagnosis of ovarian cancer. The cross-disciplinary application of multifunctional materials represents a significant trend in contemporary sensing research. In this paper, a ratio-type fluorescence sensing platform RhB/TFBBPY-COF@PBA was constructed from the covalent organic framework (COF) co-functionalized by phenylboric acid and rhodamine B (RhB). Rapid, sensitive, and accurate detection was achieved of ovarian cancer biomarker, sialic acid (SA) with a wide linear range of 0.5-400 μM, and low limit of detection (LOD) of 0.53 μM. Furthermore, a simple and convenient smartphone-assisted colorimetric sensing mode was developed by analyzing changes in fluorescence RGB values, enabling on-site detection of SA without professional instrument with a LOD of 3.66 μM. In addition, the dynamic fluorescence response of the RhB/TFBBPY-COF@PBA composite probe to SA stimulation was still utilized to design optical anti-counterfeiting labels, enabling information encryption in anti-counterfeiting. This research overcomes the limitations associated with the single functionality of traditional sensing materials and establishes a new paradigm for the application of COF materials in the triad of disease diagnosis, on-site detection, and information security. It is significant for the integration and development of precision medicine and smart materials.