The Preparation And Application Of Cerasome Based Nanocomposites As Electrode Materials

The electrochemical biosensors may be widely used in environmental protection, biomedicine, industry and agriculture and other fields because they have the advantages such as high-sensitivity, nice-selectivity, cheapness and easy-operating. Their properties have been improved and their applications field has been extended widely during years of swift development and application. However, since the direct electron transfer between enzyme and the suface of electrode resulting from the electroactive centers buried deep in the protein structures, it is important to develop novel electrodes to achieve effective direct electron transfer. Cerasome, a novel organic-inorganic hybrid nanomaterial processing a bilayer molecular membrance and Si-O-Si surface, has been proved may achieve direct electron transfer when used as the electrode material to immobilize enzyme. However, its weak conductivity contribute to the silicone surface limit its application. In this paper, we combined cerasomes and other electrical conductive nanomaterials to fabricated a series of novel biocompatible and conductive nanocomposites by electrostatic self-assembly method for the first time. Electrodes were modified with the nanocomposites and their properties such as the immobilization of enzyme, electrochemical and electrocatalytic properties were investigated. These studies provide new ideas and opportunities for construction of the third generation biosensors. The details are listed as follows:(1) Cerasome(-), Cerasome(+16), Cerasome(+12) and Liposome(+16) have been synthesized. Horseradish peroxidase (HRP) and glucose oxidase (GOD) were immobilized onto the cerasome to form HRP/Cerasome(-)/GC and GOD/Cerasome(+16)/GC modified electrodes by electrostatic self-assembly. Cyclic voltammograms was then used to characterize the electrochemical behavior of modifed electrodes. It was found that HRP/Cerasome(-)/GC electrode realized the direct electron transfer between HRP and GC electrode with a weak electrocatalytic activity. Electron can not transfer form GOD to electrode through cationic Cerasome(+16).(2) A novel biocompatibility and good conductivity nanocomposite, Au@PIL-cerasome, was fabricated via the self-assembly of gold nanoparticles coated by polymeric ionic liquid and negatively charged Cerasome(-) for the first time. A novel modified electrodes HRP/Au@PIL-Cerasome(-)/GC was prepared by immobilization of HRP on the suface of the Au@PIL-Cerasome(-)/GC modified electrode, which was made of the nanocomposite. Compared with the HRP/Au@PIL/GC electrode, HRP/Au@PIL-Cerasome/GC electrode realized the direct electron transfer between enzyme and electrode and showed better electrocatalytic activity to H2O2. The HRP/Au@PIL-cerasome/GC electrode also exhibits an excellent electrocatalytic to detection of nitrite ions and oxygen gas. QDs-Cerasome(-) composite was prepared by the positively charged mercaptoethylamine modified CdS QDs and the negetively charged Cerasome(-), on which Hb was imobilized to construct modified electrode and the cyclic voltammograms was used to study the electrocatalytic activity to H2O2. The results showed that the nanocomposite modified electrode displayed better properties.(3) Two types of nanocomposites Cerasome(+16)-CNT and Liposome(+16)-CNT were prepared by electrostatic interaction between postively charged Cerasome(+16) or Liposome(+16) and negatively charged carboxyl carbon nantube(CNT). Cerasome(+16)/CNT/GC and Liposome(+16)/CNT/GC modifed electrodes were constructed and their electrochemical properties were studied by the cyclic voltammograms. Cerasome(+16)/CNT/GC and Liposome(+16)/CNT/GC modifed electrodes showed better electron transmission properties and reversibilities. GOD/Cerasome(+16)/CNT/GC and GOD/Liposome(+16)/CNT/GC modified electrodes were fabricated with GOD by layer-by-layer electrostatic assembly and the electrochemical and catalytic properties of the modifed electrodes were studied. GOD kept its intrinsic bioactivity on the surface of the electrodes and achieved direct electron transfer. Compared with GOD/Liposome(+16)/CNT/GC and GOD/CNT/GC modified electrodes, GOD/Cerasome(+16)/CNT/GC modifed electrode exhibited wider detection range and higher sensitivity toward the detection of glucose. GOD/Cerasome(+12)/CNT/GC modified electrode had also been prepared and their electrocatalytic activity toward glucose was investigated by cyclic voltammetry. The effect of bilayer molecular membrance thickness on electrode properties was investigated. The results showed that the electrode properties were independent of the bilayer molecular membranes thickness.