Hollow TiO2modified reduced graphene oxide microspheres encapsulating hemoglobin for a mediator-free biosensor.
Hollow TiO2modified reduced graphene oxide microspheres (hollow TiO2-rGO microspheres or H-TiO2-rGO MS) have been synthesized and then be used to immobilize hemoglobin (Hb) to fabricate a mediator-free biosensor. The morphology and structure of hollow TiO2-rGO microspheres were characterized by scanning electron microscopy, transmission electronic microscopy and X-ray diffraction. Results of spectroscopy and electrochemistry tests revealed that hollow TiO2-rGO microsphere is an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. The hollow TiO2-rGO microspheres with special structure and component enhance the immobilization efficiency of proteins and facilitate the direct electron transfer, which result in the better H2O2detection performance-the wide linear range of 0.1-360μM for H2O2(sensitivity of 417.6 μA mM-1cm-2) and the extremely low detection limit of 10nM for H2O2. Moreover, the hollow microsphere can provide a protective microenvironment for Hb to make the as-prepared biosensor improve long-term stability. The as-prepared biosensor retains 95.4% of the initial response to H2O2after 60-d storage. Hence, this work suggests that if can be fabricated a mediator-free biosensor, hollow TiO2-rGO microspheres will find wide potential applications in environmental analysis and biomedical detection.
School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, PR China. Electronic address: liuhui@sust.edu.cn.
Hui
H
Liu
School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, PR China.
Kai
K
Guo
School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, PR China.
Congyue
C
Duan
School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, PR China.
Xiaonan
X
Dong
School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, PR China.
Jiaojiao
J
Gao
D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D055664:Electrochemical Techniques / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis*; D055767:Immobilized Proteins / Q000737:chemistry; D057230:Limit of Detection; D008863:Microspheres; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
D006454:Hemoglobins; D055767:Immobilized Proteins; D010087:Oxides; C009495:titanium dioxide; D006108:Graphite; D006861:Hydrogen Peroxide; D014025:Titanium
Biosensor; Direct electrochemistry; Graphene; Hollow microsphere; Long-term stability