Simultaneous SERS Sensing of Cysteine and Homocysteine in Blood Based on the CBT-Cys Click Reaction: Toward Precisive Diagnosis of Schizophrenia.

At present, there is a lack of sufficiently specific laboratory diagnostic indicators for schizophrenia. Serum homocysteine (Hcy) levels have been found to be related to schizophrenia. Cysteine (Cys) is a demethylation product in the metabolism of Hcy, and they always coexist with highly similar structures in vivo. There are few reports on the use of Cys as a diagnostic biomarker for schizophrenia in collaboration with Hcy, mainly because the rapid, economical, accurate, and high-throughput simultaneous detection of Cys and Hcy in serum is highly challenging. Herein, a click reaction-based surface-enhanced Raman spectroscopy (SERS) sensor was developed for simultaneous and selective detection of Cys and Hcy. Through the efficient and specific CBT-Cys click reaction between the probe containing cyan benzothiazole and Cys/Hcy, the tiny methylene difference between the molecular structures of Cys and Hcy was converted into the difference between the ring skeletons of the corresponding products that could be identified by plasmonic silver nanoparticle enhanced molecular fingerprint spectroscopy to realize discriminative detection. Furthermore, the SERS sensor was successfully applied to the detection in related patient serum samples, and it was found that the combined analysis of Cys and Hcy can improve the diagnostic accuracy of schizophrenia compared to a single indicator.

When AIE meets enzymes.

With the rapid development of physiopathology and the surge in demand for comprehension of micro-scale physiological events, AIE-based bio-probes are found superior in presenting precise and practical results in enzyme imaging and analysis with a high signal-to-noise ratio and non-destructive operation. By delivering enzyme-responding "light-up" fluorescence signals, the visual and real-time tracking of the distribution and activity of intracellular enzymes is accomplished with AIE-based bio-probes. In particular, by combining with modern nano-encapsulation technologies, AIE-based compounds can realize the simultaneous diagnosis and treatment of specific diseases that are difficult to deal with through traditional strategies. This review summarizes and generalizes the typical AIE-based bio-probes reported recently based on the AIE mechanisms of solubility changes, excited-state intramolecular proton transfer (ESIPT), electrostatic interactions, and hydrophobic interactions, expounding their great values in the bio-sensing and bio-medicine field. Advanced enzyme detection and estimation, cell identification, disease diagnosis, and controlled drug release are demonstrated with high confidence and reproducibility. Through the in-depth analysis of these bio-probes' design and working principles, currently existing drawbacks and further future directions are subsequently proposed to promote a more prosperous development of AIE-based enzyme probes.

Natural Flavonoid-Derived Enzyme Mimics DHKNase Balance the Two-Edged Reactive Oxygen Species Function for Wound Healing and Inflammatory Bowel Disease Therapy.

Rational regulation of reactive oxygen species (ROS) plays a vital importance in maintaining homeostasis of living biological systems. For ROS-related pathologies, chemotherapy technology derived from metal nanomaterials currently occupies a pivotal position. However, they suffer from inherent issues such as complicated synthesis, batch-to-batch variability, high cost, and potential biological toxicity caused by metal elements. Here, we reported for the first time that dual-action 3,5-dihydroxy-1-ketonaphthalene-structured small-molecule enzyme imitator (DHKNase) exhibited 2-edged ROS regulation, catering to the execution of physiology-beneficial ROS destiny among diverse pathologies in living systems. Based on this, DHKNase is validated to enable remarkable therapeutic effects in 2 classic disease models, including the pathogen-infected wound-healing model and the dextran sulfate sodium (DSS)-caused inflammatory bowel disease (IBD). This work provides a guiding landmark for developing novel natural small-molecule enzyme imitator and significantly expands their application potential in the biomedical field.