Application Of Core-Shell SERS Nanoprobes In The Detection Of Antibiotics And Hydrogen Sulfide

The abuse of antibiotic residues in water bodies and the hydrogen sulfide gas in the atmosphere cause great harm to the human body and the environment.Therefore,the establishment of on-site rapid detection technology for antibiotic residues in water bodies and hydrogen sulfide in the atmosphere has important academic value and practical significance.In recent years,there has been an increasing need for fast and accurate on-site monitoring of these substances,which has promoted the construction of portable analysis platforms.Surface Enhanced Raman Spectroscopy（SERS）is an ultra-sensitive,rapid and universal analysis tool.It does not require complex pretreatment processes for detecting samples,and has comprehensive fingerprint information.It has a wide range of applications in environmental monitoring,biomedicine,food safety and other fields.SERS reinforced substrates usually use nano-materials,whose types,properties,surface morphology,and their own structure have a certain impact on the enhancement effect.In the practical application of SERS detection,a major obstacle is the lack of an efficient and flexible method for the reproducible large-scale preparation of high-stability SERS substrates.With the rapid development of modern nanotechnology,it has become possible to synthesize highly sensitive and reproducible SERS substrates on a large scale.At the same time,combining SERS detection technology with other traditional detection methods,as a multi-sensor detection system,can improve the sensitivity of detection,reduce the detection limit,and provide greater possibilities for rapid and sensitive detection of substances.Therefore,in this paper,two different types of SERS substrates are constructed based on gold and silver nanomaterials and new MOF materials to achieve rapid screening and immediate detection of antibiotic residues in seawater,as well as rapid and sensitive detection of hydrogen sulfide gas by multi-sensing methods.Mainly carry out the following two tasks:（1）Self-installed large-area vertical silver-plated gold nanorod array Ag NPs/GNRs for simultaneous ultra-sensitive SERS detection of multiple antibiotics in seawater.In this chapter,a large-area vertical array of gold nanorods coated with nano-silver Ag NPs is prepared using self-assembly and in-situ electrochemical reduction methods.Due to the large number of Raman hotspots in the Ag NPs/GNRs array,it has excellent surface-enhanced Raman scattering effects.Between adjacent Ag NPs and GNRs,due to the close arrangement of nanostructures,it also has excellent stability and repeatability.The Ag NPs/GNRs array was used to analyze 4-aminothiophenol with high sensitivity,and the detection limit was as low as0.35p M.At the same time,by electrochemically removing adsorbed analytes and Ag NPs from the GNRs array,cyclic SERS detection can be realized.In addition,the unique performance of the Ag NPs/GNRs array was verified by analyzing multiple antibiotics at the level of tens of picomoles in environmental water samples.This research not only provides a new method for the development of a substrate material based on self-assembled vertical electroplating of silver-gold nanorod arrays,but also circumvents the traditional disposable SERS substrate and provides a huge application prospect for the simultaneous detection and stripping of environmental pollutants.（2）The preparation of noble metal-MOFs core-shell material and its sensory detection of intracellular hydrogen sulfide.This chapter successfully constructed a fluorescence-SERS dual-sensing mode nanoprobe for detecting H₂S in cells,which is mainly based on the synthesis of gold nanoparticles,and then uses bovine serum albumin（BSA）as a linker and stabilizer,in the presence of Ag⁺Using sodium borohydride in situ reduction to prepare silver cluster-coated gold nanoparticles（Ag Au NPs）under the conditions of the same conditions,introducing 4-nitrobenzenethiol（4-NTP）specific probe molecules and self-assembly of Ag Au NPs to construct a fluorescent-laden Mann’s dual-response probe material Ag Au NPs/4-NTP;finally,the Ag Au NP/4-NTP was wrapped in the organometallic frame material by the solvent method to prepare the nanocomposite Ag Au NPs@ZIF-8/4-NTP.Because the organometallic framework material has the characteristics of porosity and large specific surface area,hydrogen sulfide gas can be better enriched on the Ag Au NPs/4-NTP surface to further improve the sensitivity of fluorescence-Raman dual-channel detection.The silver clusters in the Ag Au NPs@ZIF-8/4-NTP nanocomposite probe material can undergo precipitation reaction with H₂S,and its fluorescence intensity decreases linearly with the increase of H₂S concentration,and its fluorescence detection range reaches 10^-3M-10^-13M.The detection limit is 10^-13M.At the same time,the probe material also shows strong SERS sensitivity.The reduction reaction between H₂S and 4-NTP promotes the conversion of the nitro group to the amino group on the benzene ring,resulting in a new 1591 cm^-1 Raman characteristic peak.The detection limit is as low as 10^-13M.By detecting the expression of exogenous H₂S in Hela cells,better cell imaging and detection capabilities are expressed by the probe.Therefore,the new core-shell nanoprobe constructed in this study not only has specific selectivity for H₂S,but also has excellent biomembrane permeability and cell imaging capabilities,and has potential application value in bioanalysis and medical detection.