| Optical Biosensor is a new technology,which combines the characteristics of multidisciplinary.Biological optical sensors using a biosensitive recognition element that is sensitive to biomolecules and has specific biochemical reactions,such as a variety of organizations,antibody,enzyme,avidin,nucleic acid adaptation or immune preparations,are a kind of device which can directly and accurately detect biological objects to be measured,by using signal converters,such as photoelectric signal,thermal signal reception biological signals of different sizes.In recent years,nanomaterials have had a great impact on biosensors due to their advantages of high sensitivity and specificity,which makes it possible to develop new biosensor platforms and enhance the ability to carry out specific detection of bioanalytes.Nanomaterials have a wide range of applications,involving biomedical,environmental pollution monitoring,food safety,agriculture and other fields,and their applications have broad development prospects and scientific research value.Gold nanoparticles are one of the most commonly used nanomaterials in the field of bio-optical sensing.Based on the optical properties of gold nanoparticles,the application of gold nanoparticles in agricultural biological detection was studied.The main research work is as follows:1.Gold nanoparticles with different particle sizes(13.5 um and 55 nm)were synthesized and characterized by UV-Vis extinction spectroscopy,transmission electron microscopy(TEM),etc;On the other hand,the local surface plasmon resonance effect(LSPR),FDTD electromagnetic effect and surface enhanced Raman scattering effect(SERS)of noble metal nanoparticles were introduced in detail.2.Based on the local surface plasmon resonance effect of gold nanoparticles,a nanoprobe sensing method was designed for the detection of organophosphorus pesticide malathion.The citrate on the surface of the gold nanoparticles synthesized by chemical reduction is negatively charged.At the same time,malathion hydrolysates have a negative charge.Due to the electrostatic repulsion,the LSPR effect of gold nanoparticles with different concentrations of malathion is different,showing different color reaction and peak shift of extinction spectrum.This method was simple,rapid,high sensitivity and high selectivity for the determination of organophosphorus pesticide malathion residues.3.The scattering cross section despectral and electromagnetic enhancement effect of gold nanoparticles were simulated by using FDTD.The optical properties of single gold nanoparticles with different materials,different refractive index of environmental media,different particle sizes and different shapes were simulated;At the same time,the distance between two gold nanoparticles and the optical properties of different substrates were simulated.4.Surface enhanced Raman scattering of gold nanoparticles under optimal environmental conditions was studied.Combined with the surface-enhanced Raman effect of gold nanoparticles,the maximum Raman shift of plant hormone abscisic acid was detected at 1637 cm-1,which was the stretching vibration between carbon-carbon double bonds.The results showed that there was a good linear relationship between the concentration of plant hormone ABA and the Raman intensity at 1637 cm-1.The recovery of ABA was in the range of 99.18～103.06%,and the relative standard deviation(RSD)was in the range of 3.8～6.9%.The experimental results are in good agreement with the simulation results,and the qualitative and quantitative determination of plant hormone abscisic acid is realized. |
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