Enhancement of antigen–antibody kinetics on nanotextured silicon surfaces in mixed non-flow systems

Capture of higher amount of antigen with higher efficiency by the antibodies in a minimum time is desired for enhanced performance of immunosensors. In this manuscript we report a systematic investigation of the effects of the nature of the silicon surfaces (whether nanotextured or not) on which antibodies are immobilized and the nature of the surface stacks in combination with the state of mixing of the solution (whether mixed or not) containing the antigens, on the kinetics of the antigen–antibody binding in a non-flow system. An important finding here is that the combination of nanotextured surfaces with the mixing of the analyte solution resulted in a higher antigen capture, higher efficiency of capture and a lower process time, compared to other combinations. Computer simulations using a transport-reaction model were used to extract the transport and reaction parameters from the experimental data. Analysis of these parameters (the maximum available antibodies on the surface per unit area, diffusivity, boundary layer thickness, the dissociation constant) helped to provide an understanding of the experimental results and thus the phenomena involved. Applications of this study include improving the sensitivity and response time of immunosensors in both non-flow and flowing systems.