氨基基度 (pKb) 控制单壁碳纳米管电子传感器阵列上的分析剂结合能量
Chang Young Lee1, Michael S Strano
1Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|January 15, 2008
概括
研究人员使用氨基功能化在单壁碳纳米管 (SWNT) 传感器阵列上创建了可逆吸附点. 这一突破使得高灵敏度,可逆检测分析物在每万亿分的水平,而无需再生.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
- 化学传感器 化学传感器
背景情况:
- 单壁碳纳米管 (SWNT) 网络广泛用于电子传感器和晶体管.
- 在SWNT表面上不可逆转的分析剂吸附限制了它们的传感应用.
- 这种不可逆向吸附的基本机制仍然不太清楚.
研究的目的:
- 了解和控制SWNT上的分析剂吸附机制.
- 设计SWNT表面用于可逆分析剂结合.
- 开发基于SWNT的高度敏感和可重复使用的传感器.
主要方法:
- 用氨基末端分子对SWNT数组的非共价功能化.
- 使用硫乙烯化物作为模型吸附剂来研究吸附.
- 使用X射线光电子光谱 (XPS) 和分子电位计算进行表征.
- 测试各种含氨酸的分子和聚合物胺,如聚乙烯胺 (PEI).
主要成果:
- 通过氨基功能化 (pKa < 8.8) 在SWNT阵列上成功创建了可逆吸附位点.
- 分析物的吸附受到表面氨基基群的基本性 (pKb) 的显著影响.
- 通过XPS和计算确定并支持一种降低结合能量的介导吸附机制.
- 通过使用聚乙烯胺 (PEI) 功能化而没有主动再生,实现了每万亿分的可逆检测.
结论:
- 用特定的氨基分子进行表面功能化,使SWNTs上的可逆分析剂吸附成为可能.
- 这种介导吸附机制是适用于各种基于SWNT的传感器设计的一般现象.
- 开发的方法显著提高了SWNT传感器的可重复使用性和灵敏度,用于痕迹分析物检测.
相关概念视频
01:21Basicity of Aliphatic Amines
Amines can behave as Brønsted–Lowry bases by accepting a proton from the acid to form corresponding conjugate acids. Due to a lone pair of nonbonding electrons, aliphatic amines can also act as Lewis bases by forming a covalent bond with an electrophile.
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
01:25Basicity of Heterocyclic Aromatic Amines
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
01:18Basicity of Aromatic Amines
The basicity of aromatic amines is much weaker than that of aliphatic amines due to the involvement of the lone pair of electrons over the N atom in resonance with the aryl rings. Generally, the electron-donating ability of any substituents on the aryl ring of aromatic amines increases the basicity of the amine by increasing electron density, and hence the availability of lone pair on the nitrogen. On the other hand, electron-withdrawing functional groups on the aryl ring of amines decrease the...
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This lesson delves into a critical aspect of the relative strengths of acids and bases. The strength of an acid is evaluated by the acid dissociation into its conjugate base and a hydronium ion in water. The complete dissociation of a strong acid is confirmed with a very high concentration of hydronium ions. As a result, an incomplete dissociation process affirms a weak acid. Therefore, the equilibrium is in the forward direction for strong acids and backward for weak acids in these reactions.
01:15Potentiometry: Membrane Electrodes
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