期刊
SENSORS AND ACTUATORS B-CHEMICAL
卷 285, 期 -, 页码 445-452出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.snb.2019.01.074
关键词
Direct electron transfer; Enzymatic biosensor; Nitric oxide reductase; Nitric oxide; Multiwalled carbon nanotubes; Room temperature ionic liquid
资金
- FCT/MCTES [SFRH/BD/52502/2014, PTDC/BB-BQB/0129/2014]
- FSE
- Associate Laboratory Research Unit for Green Chemistry - Technologies and Processes Clean - LAQV - FCT/MEC [UID/QUI/50006/2019]
- ERDF [POCI-01-0145-FEDER-007265]
- REQUIMTE project entitled NOR-based biosensor for nitric oxide detection in biological and environmental samples
- European Union (FEDER funds through COMPETE)
- Fundacao para a Ciencia e Tecnologia-FCT [PTDC/ASP-PES/29547/2017]
- FCT/MEC
- FEDER
- Fundação para a Ciência e a Tecnologia [PTDC/ASP-PES/29547/2017] Funding Source: FCT
Nitric oxide (NO) has a crucial role in signaling and cellular physiology in humans. Herein, a novel third-generation biosensor based on the Marinobacter hydrocarbonoclasticus metalloenzyme (nitric oxide reductase (NOR)), responsible for the NO reduction in the denitrifying processes, was developed through the direct adsorption of a new nanocomposite (multiwalled carbon nanotubes (MWCNTs)/1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4)/NOR) onto a pyrolytic graphite electrode (PGE) surface. The NOR direct electron transfer behavior (formal potential of -0.255 +/- 0.003 V vs. Ag/AgCl) and electrocatalysis towards NO reduction (-0.68 +/- 0.03 V vs. Ag/AgCl) of the PGE/[MWCNTs/BMIMBF4/NOR] biosensor were investigated in phosphate buffer at pH 6.0. Large enzyme loading (2.04 x 10(-10) mol/cm(2)), acceptable electron transfer rate between NOR and the PGE surface (k(s) = 0.35 s(-1)), and high affinity for NO (K-m = 2.17 mu mol L-1) were observed with this biosensor composition. A linear response to NO concentration (0.23-4.76 mu mol L-1) was perceived with high sensitivity (0.429 mu A/mu mol L-1), a detection limit of 0.07 mu mol L-1, appropriate repeatability (9.1% relative standard deviations (RSD)), reproducibility (6.0-11% RSD) and 80-102% recoveries. The biosensor was stable during 1 month retaining 79-116% of its initial response. These data confirmed that NOR incorporated in the MWCNTs/BMIMBF4 nanocomposite can efficiently maintain its bioactivity paving a new and effective way for NO biosensing.
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