Sensitive biological detection based on Langmuir–Blodgett films prepared from diluted silica suspensions

Abstract

Self-assembled three-dimensional (3-D) colloidal crystals have been extensively utilized in nanolithographyfor fabricating a wide spectrum of functional periodic nanostructures for important technological applications. Here asimple and versatile way is reported using silica colloids to prepare close-packed particle multilayers by the Langmuir–Blodgett technique to create highly ordered 3-D colloidal crystals with unusual nanoarrays on a large variety of substrates.Successive deposition of monolayers using amphiphilic molecules in this approach allows control of the layer thickness,particle size, and especially packing structure of them in each layer. It has been demonstrated that the Langmuir–Blodgettfilm’s transparency and high antiglare optical properties are preserved even after multiple colloidal particle transferson both straight and curved surfaces. The surface prepared by the Langmuir–Blodgett technique shows remarkablesensitivity for potential biodetection applications. These colloidal templated films have an optical response time of lessthan 40 s against essential bioproduct vapors. It is shown that the results are consistent with the Kelvin equation (lnP/Po = 􀀀2 Vl /rRT) when the liquid water layer is getting thicker.