SEU's Research Results published on German Applied Chemistry

Recently, Prof. Zhang Yuanjian's research team (https://Zhang.team) from School of Chemistry and Chemical Engineering of Southeast University and Jiangsu Province Carbon-rich Material & Device Engineering Laboratory has achieved significant progress in the regulation of nano-enzyme molecular activity center. Prof. Shen Yanfei’s research team from School of Medicine, Southeast University has achieved important progress in the clinical diagnosis of electrochemiluminescence. The research results were published in Angew. Chem. Int. Ed. (German Applied Chemistry), the top journal in the field of chemistry, with the title of "Fe-N-C Nanozyme with Both Accelerated and Inhibited Biocatalytic Activities Capable of Accessing Drug-Drug Interaction” and “Facile Preparation of WO3-x Dots with Remarkably Low Toxicity and Uncompromised Activity as Coreactants for Clinic Electrochemiluminescent Diagnosis" respectively.

The natural evolution for tens of thousands of years have endowed the natural enzymes with high activity and high substrate selectivity; however, it costs too much to isolate/purify them and they are easily deactivated under extreme conditions. To this end, the nanozyme emerges as a new generation of artificial simulated enzyme featuring not only physical and chemical properties of nanomaterials but also enzymatic catalytic functions. Since 2007 when the nano-iron oxide was first discovered to have the enzyme-like activity, more and more nanozymes have been applied to such important fields as biosensing and tumor therapy, etc. Similar to the brake and throttle of a car, it is of great significance to simulate the inhibitory effect of natural enzymes and develop more advanced biological functions of nanozymes,the same to the improvement of nanozyme activity in traditional research. Nevertheless, the lack of similar molecular activity center of natural enzymes in common nanozymes makes this research full of challenges.

In response to this problem, the team proposed simulating the higher biological functions of natural enzymes through the nanozyme Fe-Nx active molecular center, and found that the low-temperature carbonized Fe-N-C exhibited a very competitive P450-like enzyme catalytic activity. Moreover, the content and configuration of its Fe-Nx active sites together dominate the catalytic process of P450-like enzymes while indicating different electron transport pathways in comparison with the common electrochemical catalytic process. In view of the fact that P450 enzymes are involved in about 50% of the body’s endogenous and exogenous drug metabolism, and taking multiple drugs at the same time may affect the metabolism of P450 enzyme, causing adverse drug reactions or even death. This study further adopted Fe-N-C to simulate the metabolism of dihydropyridine antihypertensive drugs (1,4-DHP) by P450 enzymes. Under the joint effect of common antibacterial drugs, antibiotics or grapefruit juice, Fe-N-C exhibits similar inhibitory behavior to P450 enzymes. The mechanism study showed that the activation of oxygen molecules by the Fe-Nx active center and the different modes of function of these drugs/foods played a key role.

This study has provided a new insight for exploring the more advanced biological functions of nanozymes and also revealed that Fe-N-C will have broad application prospects in drug-drug interactions such as drug screening and drug dosage guidance, etc. in place of expensive P450 enzymes to a certain extent.

The first author of this paper is Xu Kun, a master student of Southeast University with Prof. Zhang Yuanjian as the sole corresponding author. This work was funded by the National Natural Science Foundation of China, Jiangsu Innovative and Entrepreneurial Team, and Jiangsu Provincial Science and Technology Department, etc.

Paper's link: https://doi.org/10.1002/anie.202003949

Electrochemiluminescence (ECL) detection is widely used in clinical testing because of its advantages of high sensitivity, low cost and simple equipment. Ruthenium terpyridine (Ru(bpy)32+) and its derivatives are the most commonly-used ECL emitters in clinical testing. However, as the only commercial co-reactant for Ru(bpy)32+ luminophore, tripropylamine (TPrA) still has the problems of high biological toxicity and strong background signal. Therefore, the exploration of ECL co-reactants with better performance has always been a challenge in the field of electrochemiluminescence diagnosis.

In response to the abovementioned problems, the research team developed a new green co-reactant for tungsten oxide (WO3-x) nanodots with the animal toxicity about 300 times lower than TPRA while the ECL efficiency in combination with Ru(bpy)32+ comparable with TPRA benchmark system. On this basis, this study further constructed a circulating tumor cell sensor for detecting the whole blood samples, which has overcome the shortcoming that the clinical commercial cytometer can only analyze the serum samples. It is worth mentioning that in the synthesis of WO3-x nanodots, this study proposed WS2 powder as the precursor that can be prepared by combining ultrasonic stripping and chemical conversion, thus overcoming such problems as instable reaction precursor, expensive reaction equipment, complicated synthesis process, poor electron transport performance, etc. in previous synthesis. The WO3-x nanodots as prepared feature the advantages of no ligand, sound water solubility and easy regulation of oxygen defects, etc.

This study will not only promote the application of WO3-x nanodots in clinical diagnosis, but also open up a new approach for the synthesis of WO3-x nanodots with unique structure and excellent performance.

PhD students Pan Deng, Fang Zhengzou and Yang Erli from SEU are the co-first authors of this paper with Prof. Shen Yanfei as the sole corresponding author. This study has been sponsored by National Natural Science Foundation of China, Jiangsu Provincial Department of Science and Technology and the Research Funds for the Central Universities.

Paper's link : https://doi.org/10.1002/anie.202007451