Research On Sensitive Detection Technology Based On Micro-nano Functional Materials

Biological sensitive detection technology has always been the key direction and topic of research in the fields of high-tech,food safety,and biomedicine.Optical biosensors have been more widely used compared with other sensors because their safety characteristics.In modern society,the requirement of biological sensitivity detection is gradually increasing.In response to the emerging social hotspots and the challenges posed by multiple analysis problems,researchers have been constantly pursuing new,miniaturized,highly sensitive,highly selective,and easily integrated sensing methods and technologies.Functionalized micro/nano materials can greatly improve the performance of biosensors to meet the needs of practical application in the future due to their unique microstructure and new functional properties such as optics,electricity,and catalysis.Optical biosensitivity detection technology based on micro/nano materials provides an important platform for biological detection and physiological condition detection.Optical biosensors are mainly divided into refractive index detection,surface-enhanced Raman scattering（SERS）detection,fluorescence detection,and optical absorption spectrum detection manipulation according to the detection mechanism.Among them,Refractive index detection can monitor substance because it is able to reflect the change in the refractive index around the sensor,and achieve the purpose of quantitative analysis by summarizing the law of variation.This detection plays a huge advantage in detection limit and detection time,but its disadvantage of poor specificity is also very obvious.Surface-enhanced Raman spectroscopy is famous for its"fingerprint"characteristics,which utilize the resonance frequency of molecules to achieve detection and sensing by excitation of molecular vibrations.Therefore,this paper explores the specific bottleneck of refractive index detection and the sensitivity limitation of SERS spectroscopy detection in depth.The main contents of the paper are as follows:1.The tapered fiber was prepared by melting method.After several attempts,tapered fibers of similar size to the lumbar can be fabricated repeatedly.Since the fiber itself is not selective,the surface of the tapered fiber is modified and coated with a nanomaterial graphene oxide interface to achieve better detection results.Second,precious metal nanomaterials have become the most universally applied SERS substrate due to their local surface plasma resonance effect.Therefore,this paper builds ultra-short pulses laser processing platform to prepare gold particles,and nano-sized gold particles with different enhancement effects can be obtained by controlling laser parameters and processing time.2.The detection probe of optical fiber,which use the refractive index principle for sensing,combined with specific functional materials enables real-time sensitive detection of syndrome coronavirus 2（SARS-Co V-2）.The taped fiber was firstly coated with the graphene oxide interface and then incubated RNA/DNA aptamers at this sensitive interface for specific targeting of novel coronary proteins.Graphene oxide has an exceedingly high ratio of surface and volume and excellent properties in optical and biochemical.So the adsorption capacity on the surface of tapered fibers has been markedly improved and the concentrations of detection can be as low as 6.25×10^-19M.In clinical applications,the sensing probe was used to detect 1×10^-9-M N protein mixed in fetal bovine serum samples.It can be seen from the experimental results that the sensor is able to give effective results within 3 minutes and detect N proteins of complex mechanism successfully.Therefore,the taped fiber biosensor has the the advantages of high sensitivity,easy miniaturization,and simple detection technology.It can be applied to monitor coronavirus proteins quantitatively,which helps to quickly exclude uninfected patients.3.Ultra-short pulses laser were used for reshape gold nanoparticles to achieve sensitive detection of surface-enhanced Raman spectroscopy for ultra-low concentration antibiotic detection.Gold hexagonal plates can be reshaped into a spherical-hexagonal self-assembling structure under the effect of a nanosecond laser,which can be reshaped into nano-sized spherical and triangule structure with an average size of 6 nm under femtosecond laser.The nano-sized gold particles as SERS substrates help to improve the Raman signal of ciprofloxacin.The lowest detected concentration of ciprofloxacin in milk is 7.5×10^-8M.The presented ultrafast laser reshaping of gold nanoparticles can be exploited in a wide range of plasmonic enhanced sensing applications for a simple,fast,flexible,and portable biomaterial detection.