Highly Sensitive Detection Of Myocardial Biomarker On Nano-micro Hierarchical Substrates Using SERS-Microfluidic Chip

With the continuous development of science and technology,the quality of human life is getting higher and higher,but at the same time,an increasing number of cardiovascular diseases are constantly threatening mankind.The appearance of myocardial infarction and other cardiomyocyte damage is becoming younger and younger.It can often lead to arrhythmia,shock and even life-threatening.When the human cardiomyocytes are damaged,some specific myocardial markers will be released and enter the blood circulation.The current myocardial damage and the possibility of myocardial infarction can be diagnosed by detecting these free cardiac markers.As a consequence,the fast detection of trace quantity of myocardial markers has a wide range of diagnostic testing needs.This subject researched and developed a SERS(Surface-Enhanced Raman Scattering)microfluidic chip device based on a nano-micro hierarchical substrates.By embedding the substrate into the chip,an immune complex structure is formed in the chip,which can perform rapid Raman analysis and detection of trace myocardial marker antigens.The main research contents of this paper are as follows:The first part explains the fabrication and optimization of the cone-column Raman reinforced substrate with micro-nano fold structure.We successively spread the 6-micron PS(Polystyrene)beads uniformly on the PET(polyethylene glycol terephthalate)film by solvent evaporation method and pulling film forming method,and then cut and peeled the beads into micro-patterns with flakeshaped folds and gullies on the sidewalls by oxygen plasma etching.Finally,an electron beam evaporation system is used to deposit a layer of gold film on the surface to form a SERS substrate with noble metal enhancement on the surface.Then the substrate was characterized and performance tested,and the optimized manufacturing parameters and experimental data were obtained.The second part introduces the design and fabrication of a dual-channel microfluidic system with a grooved area on the substrate.First,the designed mask was engraved on the silicon substrate by using ultraviolet lithography technology,and then the chip structure was fabricated by inverting PDMS on the silicon substrate,and the SERS substrate after the incubation modification was embedded in the chip to realize the in-chip The Raman detection model of sandwich immunoadsorption was constructed on the substrate.The third part mainly describes the experiment of using the above-mentioned microfluidic system to qualitatively and quantitatively detect two myocardial markers(cTnI is cardiac troponin I and CK-MB is creatine kinase isoenzyme).We respectively introduced mixed trace amounts of target antigens of different concentrations into the microfluidic channel,constructed the relationship between antigen concentration and SERS signal intensity,and realized the quantitative detection of target myocardial marker antigens.Then,relevant substrate-specific selectivity and uniformity tests has verified the reliability and usefulness of the substrate.Furthermore,the pleated columnar structure based on the SERS substrate has a good Raman enhancement effect,and the minimum detection limit of the target antigen can reach 0.01ng/mL.It marks that our entire detection system has good practical value and is of great significance for realizing the rapid detection of trace amounts of myocardial markers.