Fabrication of meso and nanotextured silica surfaces for tunable densities of functionalized molecules

Textured surfaces have applications in different fields including sensing. We report a method to obtain tunable textured surfaces utilizing electrostatic coupling by introducing silanized silica wafer surfaces into a sol of growing silica meso and nano particles at appropriate times specific to the process. An important finding here is that the time of introduction of the wafers into the sol had a strong effect on the surface particle densities and there exists an optimum time window of introduction for a given process to obtain the maximum surface density. The surface densities were also governed by the process used for the particle synthesis, with processes for smaller sized particles yielding higher surface particle densities. Thus by controlling the particle size and the time of introduction, the surface texture can be tuned for specific applications. This may be a cheaper alternative in specific cases to expensive (though more controlled) techniques. The texturization phenomena were studied and possible mechanisms are proposed for the observed experimental results. These textured surfaces were subsequently functionalized with biomolecules (antibodies) and the effects of the texture on the surface density of the immobilized antibodies were studied.