A Proposal of Signal Amplification Method for Biosensor Using Photo-responsive Micro-capsules

Abstract

The purpose of this study is to propose a signal amplification method for immunosensor using photo-responsive micro-capsules. A concept of photo-responsive micro-capsule which can be adapted as a signal amplification element to many kinds of biosensors was proposed. A photo-responsive micro-capsule is consisted from i) inner shell, ii) lipid bilayer, iii) outer shell, and iv) antibody layer. The inner shell was fabricated by the alternate assembly of poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDDA) on a melamine-formaldehyde (MF) particle (3 micro-meters of diameter). A highly branched protonated polyamine, poly(ethyleneimine) (PEI), was used as the first layer. The MF particle was removed by dissolution with HCl. Next, the outer shell was fabricated by TiO2. Finally, a 5-carboxy-1-pentanethiol was used to from a self-assembled monolayer (SAM) membrane and immobilize an antibody. The templating MF cores was decomposed with HCl to yield PSS/PDDA multilayer micro-capsules.