Label-free detection of angiogenesis biomarkers using Bloch surface waves on one dimensional photonic crystals

We describe the design and fabrication of biochips based on one dimensional photonic crystals supporting Bloch surface waves for label-free optical biosensing. The planar stacks of the biochips are composed of silica, tantala and titania that were deposited using plasma ion assisted evaporation under high vacuum conditions. The biochip surfaces were functionalized by silanization and appropriate fluidic cells were designed to operate in an automated platform. An angularly resolved optical sensing apparatus was assembled to carry out the sensing studies. The angular operation is obtained by a focused laser beam at a fixed wavelength and detection of the angular reflectance spectrum by means of an array detector. Practical application of the sensor was demonstrated by detecting a specific glycoprotein, Angiopoietin 2, that is involved in angiogenesis and inflammation processes. The protocol used for the label-free detection of Angiopoietin 2 is described and the results of an exemplary assay are given, confirming that an efficient detection can be achieved.