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血红蛋白修饰电极的制备及其表征

时间:2020-01-17 14:59来源:毕业论文
采用海藻酸钠(SA)包埋法制备了一种新型的血红蛋白(Hb)负载多壁碳纳米管修饰石墨电极,通过紫外-可见吸收光谱、扫描电镜(SEM)和循环伏安法等技术对电极进行了表征

摘要采用海藻酸钠(SA)包埋法制备了一种新型的血红蛋白(Hb)负载多壁碳纳米管修饰石墨电极,通过紫外-可见吸收光谱、扫描电镜(SEM)和循环伏安法等技术对电极进行了表征,揭示了其微观结构与电生物脱氯活性之间的关系。结果表明:(1)紫外-可见吸收光谱中显示Hb在pH=7的0.1 M磷酸盐缓冲液索雷氏带为405 nm,与Hb在MWCNT和SA的混合溶液的索雷氏带一致,表明了Hb在MWCNT和SA的混合溶液中保持原本结构,没有发生变性,而Hb/SA-MWCNT膜在pH溶液为2的索雷氏带基本消失,该结果说明了Hb/SA-MWCNT膜内的Hb已变性,失去了催化活性。(2)Hb/SA-MWCNT中的Hb在膜内的酰胺I和酰胺II红外吸收带(1656.3 cm-1和1544.3 cm-1)和天然Hb的吸收带(1652.8 cm-1和1537.6 cm-1)基本相同,可认为Hb在MWCNT和SA膜内基本保持了其天然结构。(3)SEM表征各种修饰电极结果表明由于SA完全包埋Hb避免了使其直接暴露于本体溶液,有利于Hb保持催化活性,使得Hb/SA-MWCNT修饰电极寿命长于Hb-MWCNT修饰电极的寿命。(4)循环伏安法结果显示pH=7.0的磷酸盐缓冲溶液中Hb/SA-MWCNT修饰石墨电极(Hb/SA-MWCNT-GE)出现一对稳定的准可逆氧化还原峰(Epc= -0.336 V和Epa= -0.198 V),该可逆峰为Hb中血红素辅基Fe(III)/Fe(II)的氧化还原峰,且Hb的还原峰电流随着TCA浓度的增加而增加。44174

毕业论文关键词:电生物;碳纳米管;血红蛋白

Abstract

Sodium alginate (SA) was prepared by embedding a new type of hemoglobin (Hb) load multi-walled carbon nanotubes modified graphite electrodes. UV - visible absorption spectroscopy, scanning electron microscopy (SEM) and cyclic voltammetry technique were characterized to reveal the relationship between the microstructure and the electrocatalytic activity in bioelectrochemical dechlorination. The results showed that: (1) The solution exhibited an absorption peak centered at 405 nm, which was related to the native absorption of the Soret band for the Hb. When SA and MWCNT were added into the solution, the feature of the absorption spectra was not changed, suggesting the Hb structure had not been denatured. And the Soret absorption bands almost disappeared as the acidity decreased at the point as low as pH 2, suggesting that the conformation of Hb in SA–MWCNT film had been changed in these acidic pH environments. (2) Hb/SA-MWCNT membrane of Hb in the amide I and amide II infrared absorption band (1656.3 cm-1 and 1544.3 cm-1), and natural Hb absorption band (1652.8 cm-1 and 1537.6 cm-1 ) were substantially the same. It suggested that Hb in the MWCNT film and SA remained its native structure. (3) SEM characterization results showed that encapsulated Hb often had higher operational stability owing to avoidance of direct exposure to bulk solution, result most likely to maintaining Hb catalytic activity. (4) Cyclic voltammetry showed that a redox peaks were observed on the Hb/SA-MWCNT-GE with the potentials at cathode peak potential (Epc= -0.336 V) and anode peak potential (Epa= -0.198 V), which could be attributed to the electrode process of electroactive center of heme Fe(III)/Fe(II) couples in the Hb molecule. When TCA was added into PBS, a significant increased in the Hb reduction peak at about -0.34 V was observed, following accompanied by a decrease of the Hb oxidation peak. The reduction peak current increased as the TCA concentration increased.

Keyword: bioelectrochemistry; Carbon nanotubes; Hemoglobin

目    录

1 引言 5

2 蛋白质的电化学研究介绍 6

2.1血红蛋白的概述 6

2.2氧化还原蛋白质直接电化学研究 6

3 实验材料 7

3.1试剂与仪器 血红蛋白修饰电极的制备及其表征:http://www.lwfree.com/yixue/lunwen_45374.html

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