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Paper   IPM / P / 12126
School of Physics
  Title:   Synthesis of Two-Dimensional Au NPs Array and Detection of Lipase-Osmolyte Interaction Based on Localized Surface Plasmon Resonance
1.  T. Ghodselahi
2.  S. Hoornam
3.  M.A. Vesaghi
4.  B. Rangbar
5.  A. Azizi
6.  H. Mobasheri
  Status:   Preprint
  Year:  2011
  Supported by:  IPM
New method for synthesis of Au nanoparticles (NPs) array by co-deposition of RFsputtering and RF-PECVD from acetylene gas and Au target is introduced. The hydrogenated amorphous carbon (a-C:H) thin film is used as intermediate material to immobilize Au NPs on the glass substrate. Deposition conditions were optimized to reach a two dimensional (2D) array of Au NPs with particle size less than 4 nm. For the first time, this type of array is utilized to detect interaction between two type osmolytes, i.e. sorbitol and trehalose, with Pesudomonace Cepacia Lipase (PCL) based on Localized Surface Plasmon Resonance (LSPR) without the need of employing probe or immobilizing PCL on the Au NPs array. From LSPR wavelength shift spectroscopy, it was found that unlike to trehalose, sorbitol interacts with PCL. This interaction increases refractive index of PCL. By Mie theory modeling of LSPR peak, refractive index of PCL in presence of different sorbitol concentration is obtained. Our Au NPs array shows a high-performance in biosensing with sensitivity 175 nm per refractive index.

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