title: Integrated Nanozymes with Nanoscale Proximity for in Vivo Neurochemical Monitoring in Living Brains.
abstract: Nanozymes, the nanostructures with enzymatic activities, have attracted considerable attention because, in comparison with natural enzymes, they offer the possibility of lowered cost, improved stability, and excellent recyclability. However, the specificity and catalytic activity of current nanozymes are still far lower than that of their natural counterparts, which in turn has limited their use such as in bioanalysis. To address these challenges, herein we report the design and development of integrated nanozymes (INAzymes) by simultaneously embedding two cascade catalysts (i.e., a molecular catalyst hemin and a natural enzyme glucose oxidase, GOx) inside zeolitic imidazolate framework (ZIF-8) nanostructures. Such integrated design endowed the INAzymes with major advantage in improved catalytic efficiency as the first enzymatic reaction occurred in close (nanoscale) proximity to the second enzyme, so products of the first reaction can be used immediately as substrates for the second reaction, thus overcoming the problems of diffusion-limited kinetics and product instability. The considerable high catalytic activity and stability enabled the INAzymes to efficiently draw a colorimetric detection of glucose with good sensitivity and selectivity. When facilitated with in vivo microdialysis, the INAzyme was successfully used for facile colorimetric visualization of cerebral glucose in the brain of living rats. Moreover, when further combined with microfluidic technology, an integrative INAzyme-based online in vivo analytical platform was constructed. The promising application of the platform was successfully illustrated by continuously monitoring the dynamic changes of striatum glucose in living rats' brain following ischemia/reperfusion. This study developed a useful approach to not only functional nanomaterial design but also advanced platforms developments for diverse targets monitoring.
authors.affiliation: College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University , Nanjing, Jiangsu 210093, China.|Collaborative Innovation Center of Chemistry for Life Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Hanjun
authors.initials: H
authors.lastname: Cheng
authors.affiliation: College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School , Nanjing, Jiangsu 210008, China.
authors.forename: Jian
authors.initials: J
authors.lastname: He
authors.affiliation: College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School , Nanjing, Jiangsu 210008, China.
authors.forename: Zhengyang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Xuejin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University , Nanjing, Jiangsu 210093, China.|Department of Biomedical Engineering, Emory University , Atlanta, Georgia 30322, United States.
authors.forename: Shuming
authors.initials: S
authors.lastname: Nie
authors.affiliation: College of Engineering and Applied Sciences, Nanjing National Laboratory of Microstructures, Nanjing University , Nanjing, Jiangsu 210093, China.|Collaborative Innovation Center of Chemistry for Life Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wei
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002384:Catalysis; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D006427:Hemin / Q000737:chemistry / Q000378:metabolism; D049329:Nanostructures / Q000737:chemistry*; D051381:Rats; D013053:Spectrophotometry; D017641:Zeolites / Q000737:chemistry
chemical_list: D017641:Zeolites; D006427:Hemin; D005949:Glucose Oxidase; D005947:Glucose