ABSTRACT
In this research we introduce a plasmonic nanoparticle based optical biosensor for monitoring of molecular binding events. The sensor utilizes spotted gold nanoparticle arrays as sensing platform. The nanoparticle spots are functionalized with capture DNA sequences complementary to the analyte (target) DNA. Upon incubation with the target sequence, it will bind on the respectively complementary functionalized particle spot. This binding changes the local refractive index, which is detected spectroscopically as the resulting changes of the localized surface plasmon resonance (LSPR) peak wavelength. In order to increase the signal, a small gold nanoparticle label is introduced. The binding can be reversed using chemical means (10 mM HCl). It is demonstrated that multiplexed detection and identification of several fungal pathogen DNA sequences subsequently on one sensor array are possible by this approach.
Subject(s)
DNA, Fungal/analysis , Nanotechnology/instrumentation , Surface Plasmon Resonance/instrumentation , Aspergillus/genetics , Aspergillus/isolation & purification , Base Sequence , Candida/genetics , Candida/isolation & purification , DNA Probes/chemistry , DNA Probes/genetics , DNA, Fungal/chemistry , Gold/chemistry , Limit of Detection , Metal Nanoparticles/chemistryABSTRACT
We present a tracking interferometer with an intrinsic compensation of the refractive index of air. By using both wavelengths of a frequency doubled Nd:YAG laser the refractive index of air can be determined and compensated by the dispersion. One dimensional benchmark verification experiments in air conditioned and typical harsh, uncontrolled environment show an asymptotic length dependent uncertainty in the order of 0.1 µm/m for distances over 10 m, proofing the potential of this approach for high accuracy measurements in industrial environments.
