The sensor can be coated with almost any material, as long as it can be applied as a thin (nm range), homogenous layer firmly attached to the underlying surface. The layer thickness can vary between nanometers and micrometers, depending on the viscoelastic properties of the applied material. QSense offers pre-coated sensors with e.g., gold, Ti, SiO2, AlO3, stainless steel, hydroxyapatite, polystyrene and biotin. Several other materials are also available, e.g., most metals, metal oxides or spin-coated polymers.
The standard sensor has a diameter of 14 mm. Because the sensor is most sensitive in the center, it is important to ensure that the same reaction is taking place over the entire surface in order to compare measurements, i.e., that your sample forms a homogeneous film.