Improved self-referenced biosensing with emphasis on multiple-resonance nanorod sensors.

We present a novel approach to improve self-referenced sensing based on multiple-resonance nanorod structures. The method employs the maximum likelihood estimation (MLE) alongside a linear response model (LM), relating the sensor response (shifts in resonance wavelengths) to the changes due to surface binding and bulk refractive index. We also provide a solution to avoid repetitive simulations, that have been previously needed to determine the adlayer thickness sensitivity when measuring biological samples of different refractive indices. The finite element method (FEM) was used to model the nanorod structure, and the nanoimprint lithography was employed to fabricate them. The standard deviation of the results based on the MLE method is lower than that associated with the LM results. The method can be applied to an extended number of resonances to achieve a higher accuracy and precision.