Roland van Vliembergen, TUE

Title: Measuring nanometer distances between micrometer-sized particles for biosensing applications
Session: Monday 5 October, 14:45


We investigate a biosensing principle based on the binding of micrometer-sized particles in solution. Target biomolecules induce two-particle clusters, which are analyzed using a rotating magnetic field and detected by scattered light. We have discovered that the scattered light intensity shows many oscillations in a 2π cluster rotation. These high frequency characteristics originate from optical interactions between the particles, as has been verified by two-particle Mie scattering simulations. Interestingly, the simulations predict a strong dependence of the oscillations on the inter-particle distance. Here we show that measured scattering signals indeed depend sensitively on the inter-particle distance, in a model system where the inter-particle distance is controlled by balancing attractive magnetic forces with repulsive electrostatic forces. The data show that inter-particle distances can be resolved with a precision of 10 nanometers, in the right range to make a distinction between clusters with and without a target biomolecule between the particles. 


 to be announced


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