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Whispering gallery mode (WGM) microtoroid optical resonators have been effectively used to sense low concentrations of biomolecules down to the single molecule limit. Optical WGM biochemical sensors such as the microtoroid operate by tracking changes in resonant frequency as particles enter the evanescent near field of the resonator. Previously, gold nanoparticles have been coupled to WGM resonators to increase the magnitude of resonance shifts via plasmonic enhancement of the electric field. However, this approach results in increased scattering from the WGM, which degrades its quality ( ) factor, making it less sensitive to extremely small frequency shifts caused by small molecules or protein conformational changes. Here, we show using simulation that precisely positioned trimer gold nanostructures generate dark modes that suppress radiation loss and can achieve high