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Enzyme Catalysis Induced Polymer Growth in Nanochannels: A New Approach to Regulate Ion Transport and to Study Enzyme Kinetics in Nanospace
Author(s) -
Dai Huang,
Li Yuqing,
Fu Yingchun,
Li Yanbin
Publication year - 2018
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201700703
Subject(s) - horseradish peroxidase , chemistry , catalysis , enzyme kinetics , substrate (aquarium) , steric effects , kinetics , enzyme catalysis , immobilized enzyme , polymer , ion , michaelis–menten kinetics , chemical engineering , nanotechnology , combinatorial chemistry , enzyme , organic chemistry , active site , enzyme assay , materials science , oceanography , physics , engineering , quantum mechanics , geology
Abstract Method that could regulate the ion transport in nanochannel in an efficient and rapid manner is still a challenge. Here, we introduced enzyme‐catalysis‐induced polymer growth in nanochannels to develop a new method to regulate the ion transport and evaluate the enzyme catalysis kinetics in nano‐space. As a model enzyme, Horseradish peroxidase (HRP) was immobilized in the nanochannels through a volume‐controlled‐drying method. In the presence of H 2 O 2 , HRP catalyzed o ‐phenylenediamine ( o ‐PD) to trigger its polymer growth, in turn blocked the ion transport and led to the decrease of the ion current. Taking advantages of the high efficiency of enzyme catalysis and the nano‐confinement of nanochannels, the system readily achieved blocking ratios of ion current even reaching 99.6 % of the initial. Based on above concept, we developed a new method to evaluate the enzyme catalysis kinetics in nano‐confined space. By comparing with those in free state in solution and absorbed on planar surface, HRP confined in nanochannels presented similar apparent Michaelis constant ( K m ) values for the substrate H 2 O 2 but much higher K m values for the substrate o ‐PD, due to the steric hindrance and diffusion suppression. The enzyme‐catalysis‐induced polymerization in nanochannels might lead to new concept for the nano‐blocking/switching and provide a new platform for single molecule analysis and detection.