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.
