Modeling and Development of a Biosensor Based on Optical Relaxation Measurements of Hybrid Nanoparticles
详细信息 查看全文
- 作者：Stefan Schrittwieser ; Frank Ludwig ; Jan Dieckhoff ; Katerina Soulantica ; Guillaume Viau ; Lise-Marie Lacroix ; Sergio Mozo Lentijo ; Rym Boubekri ; J茅r么me Maynadi茅 ; Andreas Huetten ; Hubert Brueckl ; Joerg Schotter
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：January 24, 2012
- 年：2012
- 卷：6
- 期：1
- 页码：791-801
- 全文大小：1107K
- 年卷期：v.6,no.1(January 24, 2012)
- ISSN：1936-086X
文摘
We present a new approach for homogeneous real-time immunodiagnostics (denoted as 鈥淧lasMag鈥? that can be directly carried out in sample solutions such as serum, thus promising to circumvent the need of sample preparation. It relies on highly sensitive plasmon-optical detection of the relaxation dynamics of magnetic nanoparticles immersed in the sample solution, which changes when target molecules bind to the surfaces of the nanoparticles due to the increase in their hydrodynamic radii. This method requires hybrid nanoparticles that combine both magnetic and optical anisotropic properties. Our model calculations show that core鈥搒hell nanorods with a cobalt core diameter of 6 nm, a cobalt core length of 80 nm, and a gold shell thickness of 5 nm are ideally suited as nanoprobes. On the one hand, the spectral position of the longitudinal plasmon resonance of such nanoprobes lies in the near-infrared, where the optical absorption in serum is minimal. On the other hand, the expected change in their relaxation properties on analyte binding is maximal for rotating magnetic fields as excitation in the lower kHz regime. In order to achieve high alignment ratios of the nanoprobes, the strength of the magnetic field should be around 5 mT. While realistic distributions of the nanoprobe properties result in a decrease of their mean optical extinction, the actual relaxation signal change on analyte binding is largely unaffected. These model calculations are supported by measurements on plain cobalt nanorod dispersions, which are the base component of the aspired core鈥搒hell nanoprobes currently under development.