Detection Of Biomarkers In Body Fluids Based On SERS Technology

Excess,shortage,or abnormal morphology of a certain biomarker in human body fluids is often one of the factors that cause disease.In the existing medical detection technology,the detection sensitivity of nuclear magnetic resonance method is not high,the mass spectrometry method and its combined technology are not suitable for portable detection due to the large size of the instrument and the complex sample preparation.Optical technology has advantages in single-molecule and single-cell detection,but fluorescent technology is easily affected by the environment and infrared spectrum is easily affected by water.Surface enhanced Raman spectroscopy(SERS)technology is characterized by its high sensitivity and strong adaptability.It is being more widely used in various molecular detection fields.This article uses a direct SERS detection strategy for creatinine without the need for an internal standard molecule,and an indirect SERS detection strategy for troponin T(cTnT).We have achieved the following results:(1)Developed a SERS technology for rapid and quantitative detection of creatinine in human urine.The sensitivity of SERS to creatinine detection was optimized by adjusting the type of agglomerated salt and the concentration of salt and Au sol.By developing a technique for extracting creatinine from urine,the selectivity of SERS for the analysis of complex biological matrices was improved.Comparing the results of the quantitative SERS detection with those obtained by the clinically used enzyme method,the average difference between the two methods was only 5.84%.The detection limit(LOD)of our method is 1.45 mg·L-1,while the enzymatic method is 3.4 mg·L-1.This novel method can provide a basis for diagnosis of early chronic kidney disease(CKD)and provide a high-sensitivity platform for clinical and forensic analysis.(2)Taking cTnT as the research object,a SERS immunoassay method for indirect detection of markers was developed,and the presence of weak Raman-responsive cTnT antigen was indirectly reflected by other signal molecules.The question of whether to add shell and scaffold molecules over nanoprobe synthesis is discussed in detail.The synthesis of magnetic bead substrate was introduced,and the SERS immunoassay based on the "sandwich structure" of nanoprobe particles,cTnT antigen and magnetic substrate was studied in detail.This method lays the foundation for quantitative detection of cTnT content in actual samples and is expected to provide accurate and effective information for early diagnosis of myocardial infarction.