纳米分析化学
Nano-analytical chemistry
纳米材料特征
• • • •
表面效应 体积效应 量子尺寸效应 宏观量子隧道效应
50nm
Color change of Gold Nanoparticles
SEM Imagine
AFM Imagine CdSe quantum dots
分析化学中常用的纳米材料
STM Instrument
Feedback Loop Maintains Constant Tunneling Current
X,Y
Scanner
Z
I~Ve-cd
Tip
Amp Meter d
Sample
Tip for SPM and STM
用碳纳米管促进生物分子的电子转移
• 改善生物分子的氧化还原性，降低氧化还 原的过电位。 • 促进生物分子与电极界面的直接电子传递 • 利用碳纳米管固定生物分子 • 用于免疫和DNA分析
refractive index sensors
•
The LSPR spectral position is highly dependent on the composition, size or shape of the nanoparticles, as well as the refractive index of the dielectric medium around them. the red-shift of the LSPR induced by a refractive index increase around metal nanostructures is the basis of the refractive index sensors. Local refractive index changes such as those induced by biomolecular interactions at the surface of the nanostructures can be monitored via the LSPR peak shift
Analytical Chemistry, Vol. 76, No. 17, September 1, 2004 5045
Enhancement of electron transfer by Carbon Nanotube
Figure 3. Linear scan voltammograms recorded at (a) GC/CHITand (b) GC/CNT-CHIT film electrodes in 0.10 mM NADH solution.Traces a1 and b1 were recorded in a background electrolyte solution,pH 7.40 phosphate buffer. For the clarity of presentation, traces b and b1 were shifted downward by 6 íA along the y-axis. Scan rate,50 mV s-1.
Response signal
NADH Response
Glucose
Response
Standard addition method for quantitative of a real sample
Direct electron transfer between CNT and Biomolecules • 实例 Protein Electrochemistry Using Aligned
Gas sensor and Biosensor
Streptavidin
CNT as an electrical resistance sensor
碳纳米管与纳米粒子相结合
纳米光学分析
• 基于金属纳米粒子光学分析的原理
– 局域表面等离子体共振（LSPR）
• 利用局域折射率的变化进行免疫分析 • 利用纳米粒子聚集引起的颜色变化进行生 物分析（蛋白质分析，DNA分析） • 基于光散射原理的分析技术 • 半导体纳米粒子的光学分析原理 • 用纳米粒子进行生物标记
aggregation sensors
• based on the drastic color change induced in nanoparticle aggregates due to near-field electromagnetic coupling. • for two metal nanoparticles, the resonance peak red-shifts when the interparticle separation distance decreases below the particle diameter。 • if two sets of metal nanoparticles are functionalized with complementary biomolecules, the biochemical interaction between them will induce the aggregation of the nanoparticles, which can be easily detected through the corresponding color change.
•
•
Mercury ion detection
实例 Bio-inspired colorimetric detection of Hg2+ and Pb2+heavy metal ions using Au nanoparticles
Anal Bioanal Chem (2009) 394:33–46
J. AM. CHEM. SOC. 2006, 128, 3860-3861
Another example of DNA hybridization assay
基于一维纳米材料的电化学分析
• 碳纳米管
– 特征参数：SWNT, 管径1-6nm, MWNT，层数2-50 层，层间距0.34nm.
• SPM探针 • SEM场发射电子源 • 碳纳米管的修饰
Protein Conjunction (Non-covalent bond）
J. Am. Chem. Soc. 2001, 123, 3838-3839
DNA Conjunction –One example
CNT application in DNA hybridization sensor
Change in the transistor device characteristics (DC) in the presence of an adsorbed species S. a The effect of electron transfer from S to the nanotube, b potential scattering (reducing the carrier mobility) of charge carriers by the scattering potential created by S
Direct electron transfer between CNT and Biomolecules
实例 Direct electron transfer of glucose oxidase promoted by carbon nanotubes
Analytical Biochemistry 332 (2004) 75–83
实例 Carbon Nanotube-Chitosan System for Electrochemical Sensing Based on Dehydrogenase Enzymes
The CNT-CHIT film electrodes were prepared by casting 30.0 íL of CNT-CHIT solution (0.50 wt %CHIT, 0.50 mg of CNT mL-1, pH 3.5) on the surface of a glassy carbon (GC) electrode. Evaporation of water from such a solution(1-2 h, room temperature) yielded robust surface films that contained 10 and 90 wt % CNT and CHIT, respectively
Carbon Nanotube Arrays
Microperoxidase MP-11, a small (1.9kDa) redox protein obtained by proteolytic digestion of horse heart cytochrome c,
J. AM. CHEM. SOC. 2003, 125, 9006-9007
A Colorimetric Gold Nanoparticle Sensor To Interrogate Biomolecular Interactions in Real Time on a Surface
Anal. Chem. 2002, 74, 504-509
A One-Step Homogeneous Immunoassay for Cancer Biomarker Detection Using Gold Nanoparticle Probes Coupled with Dynamic Light Scattering
• 零维纳米材料
– 金属纳米粒子
• 纳米金 • 纳米银
– 氧化物纳米材料 – 半导体纳米材料