▎ 摘　　要

NOVELTY - A poly-diallyl dimethyl ammonium chloride-reduced graphene oxide-titanium dioxide nanotubes-silver nanocomposite material solution is prepared by preparing reduced graphene oxide dispersion, preparing poly-diallyl dimethyl ammonium chloride dispersion, preparing titanium dioxide nanotubes dispersion and preparing titanium dioxide nanotubes-silver dispersion. The titanium dioxide nanotubes-silver dispersion is added to the poly-diallyl dimethyl ammonium chloride-reduced graphene oxide dispersion, stirred at room temperature for 24 hours, centrifuged, washed and dispersed the precipitate in ultrapure water to obtain the desired solution. USE - Poly-diallyl dimethyl ammonium chloride-reduced graphene oxide-titanium dioxide nanotubes-silver nanocomposite material solution. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) an electrochemical DNA aptamer sensor (2) a method for detecting lipopoly-saccharide using electrochemical DNA aptamer sensor.