糖尿病為現代社會常見的慢性病，且為我國第五大死因(民國101年)。糖尿病的主要症狀之一為高血糖，因此，監控血糖值為診斷、治療糖尿病的重要依據。本研究利用以水熱法自製的奈米片狀四氧化三鈷(Co3O4 nanosheet)催化劑，催化還原葡萄糖氧化酶(glucose oxidase, EC 1.1.3.4)與葡萄糖反應時生之過氧化氫，產生與葡萄糖濃度成正比之還原電流，發展電化學葡萄糖生化感測器，並探討其反應機構包含自由基生成反應的可能性。
　　在偵測相同濃度的葡萄糖時，以自製奈米片狀似氧化三鈷所得之還原電流強度為市售四氧化三鈷奈米顆粒之九倍。此葡萄糖生化感測器的最佳化組成如下：70%四氧化三鈷催化劑混合30%導電碳膠、1.0μL之0.5% 小牛血清蛋白水溶液、5.0μL之戊二醛水溶液以及3.0U的葡萄糖氧化酶。最佳操作條件為使用125mM Tris-HCl pH7.4緩衝溶液，旋轉電極轉速為625rpm，偵測電位為125mV下進行葡萄糖之量測。此葡萄糖生化感測在最佳化條件操作時所得的分析特性如下：線性範圍為20μM – 1500μM，靈敏度為7.252 μA /mM，偵測極限為12.51μM (S/N=3)，反應時間為40秒，標準偏差(RDS, n=20)為1.37%。另外，在魯米諾、氧化鈷、過氧化氫和TEMPO的化學發光反應中證實了本生化感測器反應機構含有自由基生成的可能性。

Diabetes mellitus is one of the leading causes of death and disability in modern world. Hyperglycemia is the major symptom of diabetes. Thus, monitoring of blood glucose is critical for diagnoses of diabetes and diabetes care. 
　　This study fabricated a glucose biosensor based on the home-made Co3O4 nanosheet catalyst. The Co3O4 nanosheet electrocatalytic reduces H2O2 which generated the biocatalytic reaction of glucose oxidase (GOx, EC 1.1.3.4). Meanwhile a response current which is proportional to the concentration of glucose is recorded by a potentiostat. This study also proposed the possible mechanism of formation of radical in the scheme of GOx/Co3O4 nanosheet glucose biosensor. 
　　The optimized GOx/Co3O4 nanosheet based glucose biosensor consist of the mixture of 70 % Co3O4 and 30 % conductive carbon ink (w/w %), 1.0 μL of 0.5 % bovine serum albumin aqueous solution, 5.0 μL of 0.5 % glutaraldehyde aqueous solution, and 3.0 units of GOx. The optimized operation conditions are in 125mM tris-HCl buffer solution at pH 7.4, The rotating speed of rotation disk electrode is 625 rpm and the applied potential is 125mV vs. Ag/AgCl (3.0M KCl). The analytical performances of the biosensor are listed in following: the linear range is 20 μM – 1500 μM, the sensitivity is 7.252 μA /mM, detection limit is 12.51μM (n=3), and the response time (t90) is 40 sec. The relative standard derivation is 1.37% (n=20). A chemiluminescence experiment was also demonstrated that the radical formation maybe possible in the scheme of GOx/Co3O4 nanosheet based glucose biosensor.

Chapter 1 Introduction	1
1-1 Biosensors : Definition, Application and Fabrication	1
1-1-1 Definition of Biosensor	1
1-1-2 Transducers	2
1-1-3 Biological Recognition Elements	3
1-1-4 Immobilization of Biological Recognition Element	3
1-2 Electrochemical Biosensors	6
1-2-1 Potentiometry	6
1-2-2 Voltammetry	7
1-2-3 Amperometry and Chronoamperometry	9
1-2-4 Application of Electrochemical biosensors	9
1-3 Modified Electrodes	10
1-3-1 Applications of Modified Electrodes	10
1-4 Diabetes Mellitus	13
1-4-1 Diabetes in the World	13
1-4-2 Causes and Classification of Diabetes	13
1-4-3 Diagnosis of Diabetes	17
1-5 Glucose Biosensors	18
1-6 Application of Co3O4	22
1-7 Preparation of Co3O4 nanomaterials	22
1-8 The Aim of this Study	25
Chapter 2 : Experimental	26
2-1 Instruments	26
2-2 Materials	27
2-3 Procedure	28
2-3-1 Home-made Co3O4 Nanosheet	28
2-3-2 Fabrication of GOx /Co3O4 Nanosheet Based Modified Electrode	28
2-4 Characterization of Home-made Co3O4 nanosheet	29
2-4-1 X-ray Diffration Patten of Co3O4 nanosheet	29
2-4-2 FTIR Spectrum of Co3O4 nanosheet	29
2-4-3 Scanning Electronic Microscope Image of Co3O4 nanosheet	29
2-4-4 Electrocatalytic Behaviors of Co3O4 nanosheet	30
2-5 Optimization of GOx/Co3O4 nanosheet based Glucose Sensor	30
2-5-1 Optimization of Buffer pH Value	30
2-5-2 Optimization of Applied Potential	30
2-5-3 Optimization of Rotating Speed of RDE	31
2-5-4 Optimization of Buffer Solution Types.	31
2-5-5 Optimization of Buffer Solution Concentration.	31
2-5-6 Optimization of Ratio of Co3O4 nanosheet in Catalyst Layer	31
2-5-7 Optimization of Glucose Oxidase Units on Glucose Biosensor	31
2-5-8 Optimization of BSA/Glutaraldehyde Ratio	32
2-6 Analytical Performance of GOx/Co3O4 nanosheet based Glucose Biosensor	32
Chapter 3 Results and Disscussion	33
3-1 Charactization of Co3O4 Nanosheet	33
3-1-1 Powder X-ray Diffraction Pattern and Fourier transform infrared spectrum of home-made Co3O4 nanosheet	33
3-1-2 Scanning Electronic Microscopy Image	35
3-1-3 Electrocacalysis of Hydrogen Peroxide and Dissolved Oxygen by Co3O4.	38
3-2 Proposed Mechanism of GOx/Co3O4 Nanosheet Based Glucose Biosensor	43
3-3 Optimization of the Biosensor	48
3-3-1 Optimization of pH	48
3-3-2 Applied Potential	50
3-3-3 Rotating Speed of RDE	51
3-3-4 Type of Buffer Solution	53
3-3-5 Concentration of Buffer Solution	55
3-3-6 Co3O4/Ink Ratio	57
3-3-7 Unit of Glucose oxidase	59
3-3-8 Ratio of BSA/Glutaraldehyde	60
3-4 Analytical Performance of GOx/Co3O4 Nanosheet Based Biosensor	63
3-5 Conclusions	68
Chapter 4 References	69

Fig 1-1 Basic construction of biosensors  2
Fig 1-2 Techniques of immobilization enzymes  6
Fig 3-1 XRD patterns of Co3O4 nanosheet  34
Fig 3-2 FTIR spectrum of Co3O4 nanosheet  35
Fig 3-3 FEG-SEM images of home-made Co3O4  37
Fig 3-4 The sensitivity to H2O2 and O2 of home-mede Co3O4 nanosheet  39
Fig 3-5 The catalytic ability of home-made Co3O¬4 nanosheet  40
Fig 3-6 The effect of calcination temperature to catalytic ability of home-made Co3O4 nanosheet modified electrode   41
Fig 3-7 The comparison of different origins of Co3O4 catalytic ability  42
Fig 3-8 The pH dependency of Co3O4 nanosheet based modified electrode  44
Fig 3-9 The chemiluminescence response of luminol in tris-HCl buffer solution
 at pH 7.4  46
Fig 3-10 The chemiluminescence response of luminol in tris-HCl buffer solution
        at pH 9.0  47
Fig 3-11 Optimization of acidity of solution  49
Fig 3-12 Optimization of applied potential  51
Fig 3-13 Optimization of speed of rotating disk electrode  53
Fig 3-14 Optimization of type of buffer solution  54
Fig 3-15 The conductivity of different type of buffer solution  55
Fig 3-16 Optimization of buffer concentration  56
Fig 3-17 The conductivity of different concentration of tris-HCl at pH 7.4  57
Fig 3-18 Optimization of Co3O4/Ink ratio  58
Fig 3-19 Optimization of units of GOx  60
Fig 3-20 Optimization of cross-linking reagent  62
Fig 3-21 The linear range of GOx/Co3O4 nanosheet based glucose biosensor  64
Fig 3-22 Relative standard derivation of GOx/Co3O4 nanosheet based
glucose biosensor  65


Table 1-1 Some commonly used transducers based on different principles  2
Table 1-2 Examples of covalent bonding immobilization of enzymes  5
Table 1-3 The criteria for the diagnosis of diabetes by American Diabetes Association  18
Table 3-1 The optimized condition of GOx/Co3O4 nanosheet based biosensor  63
Table 3-2 The analytical performance of GOx/Co3O4 nanosheet based biosensor  64
Table 3-3 The interference of coexisting species in blood  66
Table 3-4 Comparison of the glucose biosensors  67

(1) 	Newman, J. D.; Turner, A. P. F. Home blood glucose biosensors: a commercial perspective. Biosens. Bioelectron. 2005, 20, 2435–2453.
(2) 	Yoo, E.-H.; Lee, S.-Y. Glucose Biosensors: An Overview of Use in Clinical Practice. Sensors 2010, 10, 4558–4576.
(3) 	Buerk, D. G. Biosensors: Theory and Applications; CRC Press, 1995.
(4) 	Thevenot, D. R.; Toth, K.; Durst, R. A.; Wilson, G. S. Electrochemical biosensors: recommended definitions and classification. Pure Appl. Chem. 1999, 71, 2333–2348.
(5) 	Skoog, D. A.; Holler, F. J.; Crouch, S. R. Principles of instrumental analysis.; Thomson Brooks/Cole: Belmont, CA, 2007.
(6) 	Eggins, B. R. Chemical sensors and biosensors; J. Wiley: Chichester; Hoboken, NJ, 2002.
(7) 	Allen, B. L.; Kichambare, P. D.; Star, A. Carbon Nanotube Field-Effect-Transistor-Based Biosensors. Adv. Mater. 2007, 19, 1439–1451.
(8) 	Spillman, W. B. Fiber Optic Biosensors. In Fiber Optic Sensors; Udd, E.; Jr, W. B. S., Eds.; John Wiley & Sons, Inc., 2011; pp. 451–490.
(9) 	Lange, K.; Rapp, B. E.; Rapp, M. Surface acoustic wave biosensors: a review. Anal. Bioanal. Chem. 2008, 391, 1509–1519.
(10) 	Lin, M. S.; Leu, H. J. A Fe3O4-Based Chemical Sensor for Cathodic Determination of Hydrogen Peroxide. Electroanalysis 2005, 17, 2068–2073.
(11) 	Homola, J. Present and future of surface plasmon resonance biosensors. Anal. Bioanal. Chem. 2003, 377, 528–539.
(12) 	Lakard, B.; Herlem, G.; Lakard, S.; Antoniou, A.; Fahys, B. Urea potentiometric biosensor based on modified electrodes with urease immobilized on polyethylenimine films. Biosens. Bioelectron. 2004, 19, 1641–1647.
(13) 	Jorgenson, R. C.; Yee, S. S. A fiber-optic chemical sensor based on surface plasmon resonance. Sens. Actuators B Chem. 1993, 12, 213–220.
(14) 	Ronkainen, N. J.; Halsall, H. B.; Heineman, W. R. Electrochemical biosensors. Chem. Soc. Rev. 2010, 39, 1747.
(15) 	Chambers, J. P.; Arulanandam, B. P.; Matta, L. L.; Weis, A.; Valdes, J. J. Biosensor recognition elements; DTIC Document, 2008.
(16) 	Guisan, J. M. Immobilization of Enzymes and Cells; 3rd ed. 2013 edition.; Humana Press: New York, 2013.
(17) 	Wang, J.; Wang, L.; Di, J.; Tu, Y. Electrodeposition of gold nanoparticles on indium/tin oxide electrode for fabrication of a disposable hydrogen peroxide biosensor. Talanta 2009, 77, 1454–1459.
(18) 	Ekanayake, E. M. I. M.; Preethichandra, D. M. G.; Kaneto, K. Polypyrrole nanotube array sensor for enhanced adsorption of glucose oxidase in glucose biosensors. Biosens. Bioelectron. 2007, 23, 107–113.
(19) 	Sassolas, A.; Blum, L. J.; Leca-Bouvier, B. D. Immobilization strategies to develop enzymatic biosensors. Biotechnol. Adv. 2012, 30, 489–511.
(20) 	Wang, J.; Lin, M. S. Mixed plant tissue carbon paste bioelectrode. Anal. Chem. 1988, 60, 1545–1548.
(21) 	Lin, M. S.; Shih, W. C. Chromium hexacyanoferrate based glucose biosensor. Anal. Chim. Acta 1999, 381, 183–189.
(22) 	Wilchek, M.; Miron, T. Oriented versus random protein immobilization. J. Biochem. Biophys. Methods 2003, 55, 67–70.
(23) 	Delvaux, M.; Demoustier-Champagne, S. Immobilisation of glucose oxidase within metallic nanotubes arrays for application to enzyme biosensors. Biosens. Bioelectron. 2003, 18, 943–951.
(24) 	Mateo, C.; Palomo, J. M.; van Langen, L. M.; van Rantwijk, F.; Sheldon, R. A. A new, mild cross-linking methodology to prepare cross-linked enzyme aggregates. Biotechnol. Bioeng. 2004, 86, 273–276.
(25) 	Carlsson, J.; Axen, R.; Unge, T. Reversible, Covalent Immobilization of Enzymes by Thiol-Disulphide Interchange. Eur. J. Biochem. 1975, 59, 567–572.
(26) 	Grieshaber, D.; MacKenzie, R.; Voros, J.; Reimhult, E. Electrochemical Biosensors - Sensor Principles and Architectures. Sensors 2008, 8, 1400–1458.
(27) 	Hauser, P. C.; Chiang, D. W. L.; Wright, G. A. A potassium-ion selective electrode with valinomycin based poly(vinyl chloride) membrane and a poly(vinyl ferrocene) solid contact. Anal. Chim. Acta 1995, 302, 241–248.
(28) 	Dong, S.; Sun, Z.; Lu, Z. Chloride chemical sensor based on an organic conducting polypyrrole polymer. The Analyst 1988, 113, 1525.
(29) 	Janata, J. Historical review. Twenty years of ion-selective field-effect transistors. The Analyst 1994, 119, 2275.
(30) 	Bergveld, P. Thirty years of ISFETOLOGY: What happened in the past 30 years and what may happen in the next 30 years. Sens. Actuators B Chem. 2003, 88, 1–20.
(31) 	Laoire, C. O.; Mukerjee, S.; Abraham, K. M.; Plichta, E. J.; Hendrickson, M. A. Elucidating the Mechanism of Oxygen Reduction for Lithium-Air Battery Applications. J. Phys. Chem. C 2009, 113, 20127–20134.
(32) 	Bard, A. J.; Faulkner, L. R. Electrochemical methods: fundamentals and applications; Wiley: New York, 2001.
(33) 	Skoog, D. A.; Skoog, D. A. Fundamentals of analytical chemistry.; Thomson-Brooks/Cole: Belmont, CA, 2004.
(34) 	Wang, J.; Rivas, G.; Cai, X.; Palecek, E.; Nielsen, P.; Shiraishi, H.; Dontha, N.; Luo, D.; Parrado, C.; Chicharro, M.; et al. DNA electrochemical biosensors for environmental monitoring. A review. Anal. Chim. Acta 1997, 347, 1–8.
(35) 	Chiti, G.; Marrazza, G.; Mascini, M. Electrochemical DNA biosensor for environmental monitoring. Anal. Chim. Acta 2001, 427, 155–164.
(36) 	Kerman, K.; Kobayashi, M.; Tamiya, E. Recent trends in electrochemical DNA biosensor technology. Meas. Sci. Technol. 2004, 15, R1.
(37) 	Ghindilis, A. L.; Atanasov, P.; Wilkins, M.; Wilkins, E. Immunosensors: electrochemical sensing and other engineering approaches. Biosens. Bioelectron. 1998, 13, 113–131.
(38) 	Ricci, F.; Volpe, G.; Micheli, L.; Palleschi, G. A review on novel developments and applications of immunosensors in food analysis. Anal. Chim. Acta 2007, 605, 111–129.
(39) 	Prodromidis, M. I.; Karayannis, M. I. Enzyme based amperometric biosensors for food analysis. Electroanalysis 2002, 14, 241.
(40) 	Lei, Y.; Chen, W.; Mulchandani, A. Microbial biosensors. Anal. Chim. Acta 2006, 568, 200–210.
(41) 	Acha, V.; Andrews, T.; Huang, Q.; Sardar, D. K.; Hornsby, P. J. Tissue-Based Biosensors. In Recognition Receptors in Biosensors; Zourob, M., Ed.; Springer New York, 2010; pp. 365–381.
(42) 	Clark, L. C.; Lyons, C. Electrode Systems for Continuous Monitoring in Cardiovascular Surgery. Ann. N. Y. Acad. Sci. 1962, 102, 29–45.
(43) 	Murray, R. W.; Ewing, A. G.; Durst, R. A. Chemically modified electrodes. Molecular design for electroanalysis. Anal. Chem. 1987, 59, 379A–390A.
(44) 	Schneider, T. W.; Buttry, D. A. Electrochemical quartz crystal microbalance studies of adsorption and desorption of self-assembled monolayers of alkyl thiols on gold. J. Am. Chem. Soc. 1993, 115, 12391–12397.
(45) 	Uosaki, K.; Sato, Y.; Kita, H. Electrochemical characteristics of a gold electrode modified with a self-assembled monolayer of ferrocenylalkanethiols. Langmuir 1991, 7, 1510–1514.
(46) 	Chidsey, C. E. D.; Bertozzi, C. R.; Putvinski, T. M.; Mujsce, A. M. Coadsorption of ferrocene-terminated and unsubstituted alkanethiols on gold: electroactive self-assembled monolayers. J. Am. Chem. Soc. 1990, 112, 4301–4306.
(47) 	Švancara, I.; Vytřas, K.; Kalcher, K.; Walcarius, A.; Wang, J. Carbon Paste Electrodes in Facts, Numbers, and Notes: A Review on the Occasion of the 50-Years Jubilee of Carbon Paste in Electrochemistry and Electroanalysis. Electroanalysis 2009, 21, 7–28.
(48) 	Gorton, L. Carbon paste electrodes modified with enzymes, tissues, and cells. Electroanalysis 1995, 7, 23–45.
(49) 	Forzani, E. S.; Rivas, G. A.; Solı́s, V. M. Kinetic behaviour of dopamine-polyphenol oxidase on electrodes of tetrathiafulvalenium tetracyanoquinodimethanide and tetracyanoquinodimethane species. J. Electroanal. Chem. 1999, 461, 174–183.
(50) 	Bonakdar, M.; Mottola, H. A. Electrocatalysis at chemically modified electrodes : Detection/determination of redox gaseous species in continuous-flow systems. Anal. Chim. Acta 1989, 224, 305–313.
(51) 	Kulys, J. The carbon paste electrode encrusted with a microreactor as glucose biosensor. Biosens. Bioelectron. 1999, 14, 473–479.
(52) 	Wang, J.; Pamidi, P. V. A.; Park, D. S. Screen-Printable Sol−Gel Enzyme-Containing Carbon Inks. Anal. Chem. 1996, 68, 2705–2708.
(53) 	Shih, W.-C.; Yang, M.-C.; Lin, M. S. Development of disposable lipid biosensor for the determination of total cholesterol. Biosens. Bioelectron. 2009, 24, 1679–1684.
(54) 	Wang, J. Sol–gel materials for electrochemical biosensors. Anal. Chim. Acta 1999, 399, 21–27.
(55) 	Itaya, K.; Ataka, T.; Toshima, S. Spectroelectrochemistry and electrochemical preparation method of Prussian blue modified electrodes. J. Am. Chem. Soc. 1982, 104, 4767–4772.
(56) 	Itaya, K.; Uchida, I.; Neff, V. D. Electrochemistry of polynuclear transition metal cyanides: Prussian blue and its analogues. Acc. Chem. Res. 1986, 19, 162–168.
(57) 	Sabouraud, G.; Sadki, S.; Brodie, N. The mechanisms of pyrrole electropolymerization. Chem. Soc. Rev. 2000, 29, 283–293.
(58) 	Garjonyte, R.; Malinauskas, A. Glucose biosensor based on glucose oxidase immobilized in electropolymerized polypyrrole and poly(o-phenylenediamine) films on a Prussian Blue-modified electrode. Sens. Actuators B Chem. 2000, 63, 122–128.
(59) 	中華民國衛生福利部. 統計處 http://www.mohw.gov.tw/cht/DOS/Statistic.aspx?f_list_no=312&fod_list_no=2747 (accessed Apr 8, 2014).
(60) 	WHO | The top 10 causes of death http://www.who.int/mediacentre/factsheets/fs310/en/ (accessed Apr 8, 2014).
(61) 	World Health Organization. Screening for type 2 diabetes: report of a World Health Organization and International Diabetes Federation meeting; Geneva, 2003.
(62) 	WHO | Diabetes http://www.who.int/mediacentre/factsheets/fs312/en/index.html (accessed Nov 12, 2013).
(63) 	Galmer, A. Diabetes; Greenwood Press: Westport, Conn, 2008.
(64) 	American Diabetes Association. Standards of Medical Care in Diabetes--2014. Diabetes Care 2014, 37, S14–S80.
(65) 	Alberti, K. g. m. m.; Zimmet, P. z. Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: diagnosis and classification of diabetes mellitus. Provisional report of a WHO Consultation. Diabet. Med. 1998, 15, 539–553.
(66) 	Updike, S. J.; Hicks, G. P. The enzyme electrode. Nature 1967, 214, 986–988.
(67) 	Guilbault, G. G.; Lubrano, G. J. An enzyme electrode for the amperometric determination of glucose. Anal. Chim. Acta 1973, 64, 439–455.
(68) 	Wang, J.; Liu, J.; Chen, L.; Lu, F. Highly Selective Membrane-Free, Mediator-Free Glucose Biosensor. Anal. Chem. 1994, 66, 3600–3603.
(69) 	Wang, J. Carbon-Nanotube Based Electrochemical Biosensors: A Review. Electroanalysis 2005, 17, 7–14.
(70) 	Wang, J. Electrochemical glucose biosensors. Chem. Rev. 2008, 108, 814–825.
(71) 	Frew, J. E.; Hill, H. A. O. Electrochemical Biosensors. Anal. Chem. 1987, 59, 933A–944A.
(72) 	Degani, Y.; Heller, A. Direct electrical communication between chemically modified enzymes and metal electrodes. I. Electron transfer from glucose oxidase to metal electrodes via electron relays, bound covalently to the enzyme. J. Phys. Chem. 1987, 91, 1285–1289.
(73) 	Khan, G. F.; Ohwa, M.; Wernet, W. Design of a Stable Charge Transfer Complex Electrode for a Third-Generation Amperometric Glucose Sensor. Anal. Chem. 1996, 68, 2939–2945.
(74) 	Brown, D. B. Mixed-Valence Compounds: Theory and Applications in Chemistry, Physics, Geology,and Biology; Softcover reprint of the original 1st ed. 1980 edition.; Springer, 2011.
(75) 	Bartoll, J. The early use of Prussian blue in paintings. In 9th International Conference on NDT of Art, NDT, Jerusalem Israel; 2008; p. 1.
(76) 	Keggin, J. F.; Miles, F. D. Structures and Formula of the Prussian Blues and Related Compounds. Nature 1936, 137, 577–578.
(77) 	Chen, N.; Li, X.; Wang, X.; Yu, J.; Wang, J.; Tang, Z.; Akbar, S. A. Enhanced room temperature sensing of Co3O4-intercalated reduced graphene oxide based gas sensors. Sens. Actuators B Chem. 2013, 188, 902–908.
(78) 	Xia, X. H.; Tu, J. P.; Zhang, J.; Xiang, J. Y.; Wang, X. L.; Zhao, X. B. Fast electrochromic properties of self-supported Co3O4 nanowire array film. Sol. Energy Mater. Sol. Cells 2010, 94, 386–389.
(79) 	Meher, S. K.; Rao, G. R. Ultralayered Co3O4 for High-Performance Supercapacitor Applications. J. Phys. Chem. C 2011, 115, 15646–15654.
(80) 	Li, W. Y.; Xu, L. N.; Chen, J. Co3O4 Nanomaterials in Lithium-Ion Batteries and Gas Sensors. Adv. Funct. Mater. 2005, 15, 851–857.
(81) 	Patil, D.; Patil, P.; Subramanian, V.; Joy, P. A.; Potdar, H. S. Highly sensitive and fast responding CO sensor based on Co3O4 nanorods. Talanta 2010, 81, 37–43.
(82) 	Li, Y.; Tan, B.; Wu, Y. Mesoporous Co3O4 Nanowire Arrays for Lithium Ion Batteries with High Capacity and Rate Capability. Nano Lett. 2008, 8, 265–270.
(83) 	Anipsitakis, G. P.; Stathatos, E.; Dionysiou, D. D. Heterogeneous Activation of Oxone Using Co3O4. J. Phys. Chem. B 2005, 109, 13052–13055.
(84) 	Jagadeesh, R. V.; Junge, H.; Pohl, M.-M.; Radnik, J.; Bruckner, A.; Beller, M. Selective Oxidation of Alcohols to Esters Using Heterogeneous Co3O4–N@C Catalysts under Mild Conditions. J. Am. Chem. Soc. 2013, 135, 10776–10782.
(85) 	Chen, C.-H.; Chen, Y.-C.; Lin, M.-S. Amperometric determination of NADH with Co3O4 nanosheet modified electrode. Biosens. Bioelectron. 2013, 42, 379–384.
(86) 	Ding, Y.; Wang, Y.; Su, L.; Bellagamba, M.; Zhang, H.; Lei, Y. Electrospun Co3O4 nanofibers for sensitive and selective glucose detection. Biosens. Bioelectron. 2010, 26, 542–548.
(87) 	Jia, W.; Guo, M.; Zheng, Z.; Yu, T.; Rodriguez, E. G.; Wang, Y.; Lei, Y. Electrocatalytic oxidation and reduction of H2O2 on vertically aligned Co3O4 nanowalls electrode: Toward H2O2 detection. J. Electroanal. Chem. 2009, 625, 27–32.
(88) 	Leach, A. M.; McDowell, M.; Gall, K. Deformation of Top-Down and Bottom-Up Silver Nanowires. Adv. Funct. Mater. 2007, 17, 43–53.
(89) 	El Baydi, M.; Poillerat, G.; Rehspringer, J.-L.; Gautier, J. L.; Koenig, J.-F.; Chartier, P. A Sol-Gel Route for the Preparation of Co3O4 Catalyst for Oxygen Electrocatalysis in Alkaline Medium. J. Solid State Chem. 1994, 109, 281–288.
(90) 	Fujii, E.; Torii, H.; Tomozawa, A.; Takayama, R.; Hirao, T. Preparation of cobalt oxide films by plasma-enhanced metalorganic chemical vapour deposition. J. Mater. Sci. 1995, 30, 6013–6018.
(91) 	Lakshmi, B. B.; Patrissi, C. J.; Martin, C. R. Sol−Gel Template Synthesis of Semiconductor Oxide Micro- and Nanostructures. Chem. Mater. 1997, 9, 2544–2550.
(92) 	Liu, Y.; Wang, G.; Xu, C.; Wang, W. Fabrication of Co3O4 nanorods by calcination of precursor powders prepared in a novel inverse microemulsion. Chem. Commun. 2002, 1486–1487.
(93) 	Shi, X.; Han, S.; Sanedrin, R. J.; Galvez, C.; Ho, D. G.; Hernandez, B.; Zhou, F.; Selke, M. Formation of Cobalt Oxide Nanotubes:  Effect of Intermolecular Hydrogen Bonding between Co(III) Complex Precursors Incorporated onto Colloidal Templates. Nano Lett. 2002, 2, 289–293.
(94) 	He, T.; Chen, D.; Jiao, X. Controlled Synthesis of Co3O4 Nanoparticles through Oriented Aggregation. Chem. Mater. 2004, 16, 737–743.
(95) 	Jiu, J.; Ge, Y.; Li, X.; Nie, L. Preparation of Co3O4 nanoparticles by a polymer combustion route. Mater. Lett. 2002, 54, 260–263.
(96) 	Liu, Q.; Zhang, W.-M.; Cui, Z.-M.; Zhang, B.; Wan, L.-J.; Song, W.-G. Aqueous route for mesoporous metal oxides using inorganic metal source and their applications. Microporous Mesoporous Mater. 2007, 100, 233–240.
(97) 	Xue, X.-Y.; Yuan, S.; Xing, L.-L.; Chen, Z.-H.; He, B.; Chen, Y.-J. Porous Co3O4 nanoneedle arrays growing directly on copper foils and their ultrafast charging/discharging as lithium-ion battery anodes. Chem. Commun. 2011, 47, 4718–4720.
(98) 	Makhlouf, M. T.; Abu-Zied, B. M.; Mansoure, T. H. Effect of calcination temperature on the H2O2 decomposition activity of nano-crystalline Co3O4 prepared by combustion method. Appl. Surf. Sci. 2013, 274, 45–52.
(99) 	Wang, Y.-Z.; Zhao, Y.-X.; Gao, C.-G.; Liu, D.-S. Preparation and catalytic performance of Co3O4 catalysts for low-temperature CO oxidation. Catal. Lett. 2007, 116, 136–142.
(100) Shaheen, W. M.; Selim, M. M. Thermal characterization and catalytic properties of the ZnO–Co3O4/Al2O3 system. Int. J. Inorg. Mater. 2001, 3, 417–425.
(101) Abu-Zied, B. M.; Soliman, S. A. Nitrous Oxide Decomposition Over MCO3–Co3O4 (M = Ca, Sr, Ba) Catalysts. Catal. Lett. 2009, 132, 299–310.
(102) Christoskova, S. G.; Stoyanova, M.; Georgieva, M.; Mehandjiev, D. Preparation and characterization of a higher cobalt oxide. Mater. Chem. Phys. 1999, 60, 39–43.
(103) Wang, H.; Zhang, L.; Tan, X.; Holt, C. M. B.; Zahiri, B.; Olsen, B. C.; Mitlin, D. Supercapacitive Properties of Hydrothermally Synthesized Co3O4 Nanostructures. J. Phys. Chem. C 2011, 115, 17599–17605.
(104) Hamdani, M.; Singh, R. N.; Chartier, P. Co3O4 and Co-based spinel oxides bifunctional oxygen electrodes. Int J Electrochem Sci 2010, 5, 556–577.
(105) Brown, G. E.; Henrich, V. E.; Casey, W. H.; Clark, D. L.; Eggleston, C.; Felmy, A.; Goodman, D. W.; Gratzel, M.; Maciel, G.; McCarthy, M. I.; et al. Metal Oxide Surfaces and Their Interactions with Aqueous Solutions and Microbial Organisms. Chem. Rev. 1999, 99, 77–174.
(106) Mate, V. R.; Shirai, M.; Rode, C. V. Heterogeneous Co3O4 catalyst for selective oxidation of aqueous veratryl alcohol using molecular oxygen. Catal. Commun. 2013, 33, 66–69.
(107) Dong, J.; Song, L.; Yin, J.-J.; He, W.; Wu, Y.; Gu, N.; Zhang, Y. Co3O4 Nanoparticles with Multi-Enzyme Activities and Their Application in Immunohistochemical Assay. ACS Appl. Mater. Interfaces 2014, 6, 1959–1970.
(108) Fenton, H. J. H. LXXIII.—Oxidation of tartaric acid in presence of iron. J. Chem. Soc. Trans. 1894, 65, 899–910.
(109) Neyens, E.; Baeyens, J. A review of classic Fenton’s peroxidation as an advanced oxidation technique. J. Hazard. Mater. 2003, 98, 33–50.
(110) Moura, F. C. C.; Araujo, M. H.; Costa, R. C. C.; Fabris, J. D.; Ardisson, J. D.; Macedo, W. A. A.; Lago, R. M. Efficient use of Fe metal as an electron transfer agent in a heterogeneous Fenton system based on Fe0/Fe3O4 composites. Chemosphere 2005, 60, 1118–1123.
(111) 	Lin, S.-S.; Gurol, M. D. Catalytic decomposition of hydrogen peroxide on iron oxide: kinetics, mechanism, and implications. Environ. Sci. Technol. 1998, 32, 1417–1423.
(112) Khan, P.; Idrees, D.; Moxley, M. A.; Corbett, J. A.; Ahmad, F.; Figura, G. von; Sly, W. S.; Waheed, A.; Hassan, M. I. Luminol-Based Chemiluminescent Signals: Clinical and Non-clinical Application and Future Uses. Appl. Biochem. Biotechnol. 2014, 173, 333–355.
(113) Li, Y.; Zhu, H.; Trush, M. A. Detection of mitochondria-derived reactive oxygen species production by the chemilumigenic probes lucigenin and luminol. Biochim. Biophys. Acta BBA - Gen. Subj. 1999, 1428, 1–12.
(114) Wong, C. M.; Wong, K. H.; Chen, X. D. Glucose oxidase: natural occurrence, function, properties and industrial applications. Appl. Microbiol. Biotechnol. 2008, 78, 927–938.
(115) Fleischmann, M.; Pons, S. The behavior of microelectrodes. Anal. Chem. 1987, 59, 1391A–1399A.
(116) Hicks, M.; Gebicki, J. M. Rate constants for reaction of hydroxyl radicals with Tris, Tricine and Hepes buffers. FEBS Lett. 1986, 199, 92–94.
(117) Lousada, C. M.; LaVerne, J. A.; Jonsson, M. Enhanced hydrogen formation during the catalytic decomposition of H2O2 on metal oxide surfaces in the presence of HO radical scavengers. Phys. Chem. Chem. Phys. 2013, 15, 12674.
(118) Llano, J.; Eriksson, L. A. Mechanism of Hydroxyl Radical Addition to Imidazole and Subsequent Water Elimination. J. Phys. Chem. B 1999, 103, 5598–5607.
(119) Mohapatra, S. N.; Costeloe, K. L.; Hill, D. W. Blood resistivity and its implications for the calculation of cardiac output by the thoracic electrical impedance technique. Intensive Care Med. 1977, 3, 63–67.
(120) Sakamoto, S.; Yoshinaka, M.; Hirota, K.; Yamaguchi, O. Fabrication, Mechanical Properties, and Electrical Conductivity of Co3O4 Ceramics. J. Am. Ceram. Soc. 1997, 80, 267–268.
(121) Lehninger, A. L.; Nelson, D. L.; Cox, M. M. Lehninger principles of biochemistry; W.H. Freeman: New York, 2005.
(122) Mateo, C.; Palomo, J. M.; van Langen, L. M.; van Rantwijk, F.; Sheldon, R. A. A new, mild cross-linking methodology to prepare cross-linked enzyme aggregates. Biotechnol. Bioeng. 2004, 86, 273–276.
(123) Barsan, M.; Klincar, J.; Batic, M.; Brett, C. Design and application of a flow cell for carbon-film based electrochemical enzyme biosensors. Talanta 2007, 71, 1893–1900.
(124) Shah, S.; Sharma, A.; Gupta, M. N. Preparation of cross-linked enzyme aggregates by using bovine serum albumin as a proteic feeder. Anal. Biochem. 2006, 351, 207–213.
(125) Liu, X.; Shi, L.; Niu, W.; Li, H.; Xu, G. Amperometric glucose biosensor based on single-walled carbon nanohorns. Biosens. Bioelectron. 2008, 23, 1887–1890.
(126) Sharma, S.; Gupta, N.; Srivastava, S. Modulating electron transfer properties of gold nanoparticles for efficient biosensing. Biosens. Bioelectron. 2012, 37, 30–37.
(127) Si, P.; Ding, S.; Yuan, J.; Lou, X. W. (David); Kim, D.-H. Hierarchically Structured One-Dimensional TiO2 for Protein Immobilization, Direct Electrochemistry, and Mediator-Free Glucose Sensing. ACS Nano 2011, 5, 7617–7626.
(128) Yang, K.; She, G.-W.; Wang, H.; Ou, X.-M.; Zhang, X.-H.; Lee, C.-S.; Lee, S.-T. ZnO Nanotube Arrays as Biosensors for Glucose. J. Phys. Chem. C 2009, 113, 20169–20172.
(129) Cai, C.-J.; Xu, M.-W.; Bao, S.-J.; Lei, C.; Jia, D.-Z. A facile route for constructing a graphene-chitosan-ZrO2 composite for direct electron transfer and glucose sensing. RSC Adv. 2012, 2, 8172–8178.
(130) Umar, A.; Rahman, M. M.; Al-Hajry, A.; Hahn, Y.-B. Enzymatic glucose biosensor based on flower-shaped copper oxide nanostructures composed of thin nanosheets. Electrochem. Commun. 2009, 11, 278–281.
(131) Kaushik, A.; Khan, R.; Solanki, P. R.; Pandey, P.; Alam, J.; Ahmad, S.; Malhotra, B. D. Iron oxide nanoparticles–chitosan composite based glucose biosensor. Biosens. Bioelectron. 2008, 24, 676–683.
(132) Wang, K.; Xu, J.-J.; Chen, H.-Y. A novel glucose biosensor based on the nanoscaled cobalt phthalocyanine–glucose oxidase biocomposite. Biosens. Bioelectron. 2005, 20, 1388–1396.
(133) Hou, C.; Xu, Q.; Yin, L.; Hu, X. Metal–organic framework templated synthesis of Co3O4 nanoparticles for direct glucose and H2O2 detection. The Analyst 2012, 137, 5803.