Carboxylated Gold Coated Substrates

Ssens can provide any surface with any type of chemical functionality. The most common functionality is the carboxylic acid group. These groups can be used in immobilization reactions, for instance by using aqueous carbodiimide chemistry.

The functional surfaces are divided into two categories; on the P-type substrates the functional groups are present in a thin planar surface layer whereas on the G-type surface the functional groups are present in a 3 dimensional, gel-like layer.

Upon immobilization of a ligand to these functional groups, the interaction with these surfaces is not only determined by the nature of the ligand but also by the nature of the background onto which the ligand is immobilized. Ssens supplies surfaces with different types of background. Upon contact with biological samples (e.g. protein solutions), the surfaces will show no or minimal a-specific interaction whereas during preparation of the other surfaces no special effort is made to prevent such a-specific interaction.

Standard gold coatings are 20 or 200 nm thick, with the 20 nm being semi-transparent and the 200 nm optically closed. Furthermore, we supply gold coated substrates that are especially suited for optical microscopy (35-45% transparency). These substrates have an almost uniform (±3%) transparency for light of a wavelength in the 'visible' range (400 - 800 nm).

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