Amine-Anchored Nanoscale Covalent-Organic Framework for Detecting Kynurenine and Mitoxantrone from Biofluids and Environmental Water

Kynurenine (KYN) is a crucial biomarker, whereas mitoxantrone (MTX) is a cancer-treatment drug. Both are vital for biomedical research and enhanced disease management from a point of view. KYN, a body metabolite, plays a role in numerous diseases, and its detection can aid in developing therapeutic strategies for diseases such as cancer, inflammation, Alzheimer’s, and Parkinson’s. Conversely, monitoring MTX is essential to regulate its concentration in drinking water and within the human body, ensuring the safety of all living beings, including humans. To tackle these challenges, we developed an amine-rich, nanoscale porous covalent-organic framework (SNW-1@NH2 COF). This robust nano-COF efficiently detects KYN and MTX through a fluorescence turn-off mechanism. This is the first report of a COF to detect KYN and MTX. The SNW-1@NH2 COF can rapidly recognize KYN in human body fluids and MTX in human body fluids and environmental water samples. This recyclable sensor has exceptionally high sensitivity with limit of detection (LOD) values of 0.3 nM for KYN and 8.8 nM for MTX. Additionally, we introduced a chitosan and COF-coated robust paper strip device for user-friendly, real-world applications. The SNW-1@NH2@Chitosan@Paper strip composite provides a versatile platform for detecting KYN and MTX across a broad concentration range, from micromolar to nanomolar levels. Furthermore, the intra- and interday precision and reproducibility of the SNW-1@NH2 COF were thoroughly verified, demonstrating its reproducibility and consistency under many circumstances. Various analytical experiments and computational calculations were conducted to elucidate the underlying mechanisms enabling KYN and MTX nanomolar-level sensing.