A probe-target reaction is made more recognizable by the provision of a mass-enhancing and/or evanescent-field-perturbing amplifier element which reacts uniquely with and binds to the probe-target pair to provide increased mass. Where the probe-target pair is hybridized dsDNA, a suitable mass-enhancing amplifier is anti-double stranded DNA mouse IgM. In examples with sufficient sequence pairs in the probe-target combination, a sequence-specific minor-groove-binding polyamide can be used that carries biotin which can be amplified by streptavidin in a suitable carrier. In a preferred embodiment, a plurality of probes are immobilized at the sites of a microarray, each probe being specific to a different target. Optics utilizing total internal reflection are described for observing perturbation of the evanescent field.