| In this thesis,the study mainly covers four aspects:1) The Cys-His-His self-assembled monolayer coordinated with copper ions as the superoxide dismutase mimic for the electrochemical superoxide determiantion.2) Synthesis and surface assembly of 4-(mercaptobutyl)triethylene glycol and its property for the nonspecific protein adsorption.3) The amplitude modulated chlorophyll fluorometery of Alga suspension cells used for the detection of herbicide.4) Cell-based biosensor using gold nanoparticles as the signal enhancing agent for the detection of PSⅡinhibiting herbicides.1) A superoxide dimutase mimic biosensor was formed by using a Cys-His-His tripeptide as ligands to immobilize copper ion.The electrochemical behavior of the Cu/CHH-modified was studied in phosphate buffer solution by cyclic voltammetery, goniometry,and the assembled monolayer constituents were demonstrated by X-ray photoelectron spectroscopy as well as electrochemical methods.The steady-state current responses at 350 and -150mV were proportional to the concentration of O2 - generation in the range of～9.36 to 65μM.The sensitivity of Cu/CHH/Au was found to be 1.042×10-4 AM-1 and 2.36×10-4 AM-1 at 350 and -150 mV,respectively.2) A compound 4-(mercaptobutyl)triethylene glycol was synthesized starting with the triethylene glycol and 1,4-dibromobutane.The molecular structure of the target compound was confirmed by 1H NMR,GC-MS,IR,etc.Then the compound was used for the formation of a self-assembled monolayer(SAM) on gold electrode,and characteristics of the self-assembled monolayer were investigated by the electrochemical cyclic voltammetry and electrochemical impendence spectra.As a result,the self-assembled monolayer showed a strong anti-nonspecific adsorption to the protein BSA,as demonstrated by the surface plasmon resonance technology.3) Alga cell(PCC 7942) suspension was cultured in batch cultures in 250 mL conical flasks using the BG 11 medium.The amplitude modulated chlorophyll fluorometery of the alga cell suspension was used for the detection of herbicide.Thus,a D1 protein inhibitive herbicide,atrazine,was employed for inhibition of the photosynthetic current,and the resulted fluorescence change of chlorophylls in the alga cell suspension was used for the detection of the herbicide atrazine.When the concentration of atrazine was 10-5 mol/L or 10-6 mol/L,the electron transfer of photosystemⅡwas completely inhibited,but incomplete inhibition was observed at the concentration of 10-7 mol/L.When the concentration was reduced to 10-10 mol/L,almost no inhibition was observed.4) The solution of gold nanoparticals and chitosan was used for the encapture of plant cells from alga,and formed a kind of cell-based biosensor by casting on an electrode surface.Since the introduction of gold nanoparticles in the composite membrane,the signal of amperometric current response at 250mV was enhanced about twofold,compared with the signal without gold nanoparticles under the same condition. It was found 50%inhibition of the photocurrent at the concentration of 5×10-8 mol/L for atrazine.The biosensor exhibited an amperometric current response with a good linear correlation to the logarithmic value of the concentration of atrazine ranging from 1×10-6 to 1×10-8 mol/L. |
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