Surfaced-enhanced Spectral Sensors Based On AuNPs For Sensing Biomolecules And Organic Molecules

Sensors are widely used in every field because they could be a detector that surmount the human senses.Surface-enhanced spectral sensors have attracted great interest in research of sensors,because of their outstanding sensitivity.Surface-enhanced spectral sensors are analytic devices composed of spectral sensor and signal signal conversion components for analytical detection.Gold nanoparticles exhibit outstanding surface effect,the quantum size effect,unique biocompatibility,optical and chemical properties,in addition,theirshape and size can be controlled,so they are widely used in surface-enhanced spectral sensors.New class of multifunctional materials can be fabricated to complement properties and applications of different materials by combining gold nano-material and other materials,which have great potential in applications of surface-enhanced spectral sensors.In recent years,the researchers have constructed several surface-enhanced spectral sensors and used in chemical and biological analysis by using materials based on gold nano-materials.In this thesis,we developed a fluorescent sensor with high and tunable sensing performance withgood sensitivity and wide detection range and a surface-enhanced Raman sensor which can be fabricated in a simple and rapid method.The main research contents are as follows:?1?A type of fluorescent sensor could be regulated by the polyA has been generated for fluorescence detection of ATP based on the strong absorption between the polyA and the gold nanoparticals.We designed a diblock oligonucleotides on the surface of AuNps which contained a signal segment for the ATP recognition and a polyA segment for anchoring on the surface of Au nanopartical.In the presence of ATP molecules,the single strand DNA was released and the fluorescence of Cy3 was restored which is because the specific DNA could be formed between the ATP aptamer and ATP to formed a more stable hairpin structure on the surface of gold nanopartical surface,thus,a sensitive and selective fluorescent sensor could be have to detect ATP.This fluorescent sensors was safty that could sensitive assay of ATP,in addition,the polyA segment could modulate density of DNA on AuNPs by adjusting its length.We thus believe it will has important research significance in material analysis,molecular diagnostics and other fields.?2?We constructed a surface-enhanced Raman sensor for sensitive deteciton of 4-MBA based on gold nanoparticles and mesoporous silica by used of the unique localized surface plasmon resonance?LSPR?properties of Au nanoparticals.A series of characterization methods had been used in the characterization of mesoporous silicas which show that a lot of gold nanoparticles loaded in the well-regulated channel of silicas,the electromagnetic field in the"hot spot"areas between the gold nanoparticles was greatly enhanced under the excitation of the light,the Raman signal of 4-MBA molecules was largely enhanced when they located in this areas.In addition,this paper explored the detection effect of the surface enhanced Raman sensor by changed the gold content,the calcination temperature and other different conditions.This surface-enhanced Raman sensors was safty that could sensitive assay of 4-MBA,in addition,we could prepare AuNP/SiO2 substrate in a simple and rapid way which may met the need of industrialization.More importantly,this composited materials could be used as a promising drug carrier by modified some functional groups,we belived it will have a more extensive application in analytical chemistry,material chemistry,molecular biology.?3?We constructed a surface-enhanced Raman sensor for sensitive deteciton of 4-MBA based on gold nanoparticles,mesoporous silica and ferroferric oxide by used of the unique localized surface plasmon resonance?LSPR?properties of Au nanoparticals and magnetism of materials.SEM?TEM?BET?XRD had been used in the characterization of composite which show that a lot of gold nanoparticles and Fe₃O₄ loaded in the well-regulated channel of silicas and the SERS was greatly enhanced contributed to the magnetism of materials.This surface-enhanced Raman sensors was safty that could sensitive assay of 4-MBA,in addition,it could respond down to 10-7M of 4-MBA,according to the research,AuNP/SiO2/Fe₃O₄ could became a SERS substrate to building the surface enhanced Raman sensor.