| Year | 2017 |
|---|---|
| Journal Info. | Analytical Chemistry, 89, 124-137 (2017) |
| Author | Xiuli Fu, Lingxin Chen* and Jaebum Choo* |
| etc. |
Abstract
anomaterials exhibit unique physical and chemical properties that make them excellent scaffolds for the fabrication of novel optical nanoprobes. As a result of the properties afforded by the highly tunable size and shapedependent features of nanomaterials, their large surface-tovolumeratios, and their conjugations with desired specificity or assemblies with desired signal transduction mechanisms, nanomaterial-based sensors can markedly improve the sensitivity and specificity of analyte detection. These unique properties of nanomaterials, as well as their overall structural robustness, make them highly amenable for use in various sensor platforms. Accordingly, myriad nanomaterial-based immunoassay approaches have been developed employing various kinds of nanomaterials such as noble metal nanoparticles, quantum dots (QDs), upconversion nanomaterials, and carbon nanomaterials. In particular, enormous attention has been paid to the development of signal amplification strategies using optical nanoprobes in immunoassays in order to realize high sensitivity and selectivity for the detection of analytes. For instance, in the traditional sandwich-type immunoassay, an enzyme-labeled detection antibody is used as the indicator to amplify the detection signal. However, the sensitivity of this system is often limited because of the 1:1 ratio between the enzyme and the detection antibody. Nanomaterials and nanotechnology bring exciting new possibilities for the development of advanced optical immunoassay strategies. To achieve this goal, nanomaterials are usually employed (a) as supports for the loading of numerous indicators (e.g., biomolecules, fluorescent dyes, or Raman reporters) to amplify the recognition event through their high surface-to-volume ratio or (b) as the indicator that is generated with the aid of biochemical reactions to achieve multiple signal amplification. In this Review, we will focus on the most recent advances in the field of nanomaterial-based sensitive immunoassay. First, we will give a brief overview of the properties of nanomaterials and basic modification methods. Next, we will introduce various novel types of high sensitivity nanomaterial-based optical immunosensors categorized by different signal detection strategies: colorimetry/UV−vis spectra, fluorometry, and surface-enhanced Raman scattering. Finally, we will present the challenges and provide some perspectives on the future trends of this field.
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