Study on the layer-by-layer electrostatic self assembly method for biomolecule immobilization onto biosensor surface

Abstract

Layer-by-layer electrostatic self-assembly (L-b-L ESA) method was used for the immobilization of biomolecules onto the sensor substrate surface. As opposed to the LB method, L-b-L ESA is independent of the substrate size and topology. In addition, the LB technique typically cannot be used to form films thicker than several monolayers because defects occur and are replicated through the film structure as additional layers are added. Unlike LB schemes, L-b-L ESA processing permits the molecular-level self-healing of defects that may occur in individual monolayers as additional monolayers are gradually added layer by layer to the substrate during the synthesis process. Individual layer thickness is controllable by factors such as concentration, molecular weight, and ionic strength. What's more, the process is performed with water-soluble molecules, which is required for many biological macromolecules. Any solvent-accessible surface is appropriate for the coatings. Last but not the least, in comparison with LB or physical vapor deposition techniques; the instrumentation cost is very low. Experiment results have demonstrated successful immobilization of Oligonucleotide onto fused silica optical fiber tip by means of L-b-L ESA. The method is shown to be fast, simple and cost-efficient. This will provide a viable, simple and fast method for biomolecule immobilization for a large number of various biosensors.