Backscattering Interferometry: From Modeling and Fabrication to Application

Abstract

The movement of molecular analyses to u-TAS formats has grown exponentially over the past decade. This in turn has led to the development of new and innovative detection schemes to perform analyses on micro- and nanoarrays. The need for femto- to zeptomole detection limits, small probe volumes, low reagent consumption, and preferably label free detection has become paramount in the new analytical devices of today. However, many proposed new detection schemes rely on solid supports where elaborate surface chemistries are required for immobilization of an analyte. A number of intangibles can interfere and limit reactions in these types of solid support arrays often time giving erroneous data. The ability to perform solution phase molecular interactions in a u-TAS format would forgo any of the limitations related to substrate bound determinations. Here is described a detection modality founded in the fundamentals of interferometry which offers such utility. The optics and light propagation through this optical system are instrumental in the performance of the detector and were thus profoundly studied. The microchips used in these molecular assays were determined to be a key factor in the sensitivity of the interferometer and be capable of influencing the interaction. Many biologically relevant applications were extensively studied, not only exhibiting the feasibility of the instrument but its superiority in many cases.