Amine-Anchored Nanoscale\nCovalent-Organic Framework\nfor Detecting Kynurenine and Mitoxantrone from Biofluids and Environmental\nWater

Kynurenine (KYN) is a crucial biomarker, whereas mitoxantrone\n(MTX)\nis a cancer-treatment drug. Both are vital for biomedical research\nand enhanced disease management from a point of view. KYN, a body\nmetabolite, plays a role in numerous diseases, and its detection can\naid in developing therapeutic strategies for diseases such as cancer,\ninflammation, Alzheimer’s, and Parkinson’s. Conversely,\nmonitoring MTX is essential to regulate its concentration in drinking\nwater and within the human body, ensuring the safety of all living\nbeings, including humans. To tackle these challenges, we developed\nan amine-rich, nanoscale porous covalent-organic framework (<b>SNW-1@NH</b><sub><b>2</b></sub> COF). This robust nano-COF\nefficiently detects KYN and MTX through a fluorescence turn-off mechanism.\nThi<b>s</b> is the first report of a COF to detect KYN and MTX.\nThe <b>SNW-1@NH</b><sub><b>2</b></sub> COF can rapidly\nrecognize KYN in human body fluids and MTX in human body fluids and\nenvironmental water samples. This recyclable sensor has exceptionally\nhigh sensitivity with limit of detection (LOD) values of 0.3 nM for\nKYN and 8.8 nM for MTX. Additionally, we introduced a chitosan and\nCOF-coated robust paper strip device for user-friendly, real-world\napplications. The <b>SNW-1@NH</b><sub><b>2</b></sub><b>@Chitosan@Paper</b> strip composite provides a versatile platform\nfor detecting KYN and MTX across a broad concentration range, from\nmicromolar to nanomolar levels. Furthermore, the intra- and interday\nprecision and reproducibility of the <b>SNW-1@NH</b><sub><b>2</b></sub> COF were thoroughly verified, demonstrating its reproducibility\nand consistency under many circumstances. Various analytical experiments\nand computational calculations were conducted to elucidate the underlying\nmechanisms enabling KYN and MTX nanomolar-level sensing.