Preparation Of Ordered Nanopore Array SERS Substrate And Its Application In Cancer Exosome Detection

Early diagnosis of cancer is essential to reduce the mortality rate of cancer.One of the effective ways to realize early diagnosis is to detect the expression level of tumor markers.Exosomes are a new type of cancer biomarkers that carry rich biological molecules(proteins,nucleic acids,etc.).Since exosomes originate from donor cells,the detection of tumor exosomes with high sensitivity,high throughput and low cost is of great significance for the early diagnosis of cancer.This paper mainly studies the construction of a SERS microfluidic chip and its application in the detection of cancer exosomes.An ordered nanopore array based SERS substrate is proposed.By integrating the array into a microfluidic chip,a SERS detection platform for exosomes is constructed and applied to detect human serum samples.This platform provides an effective solution for clinical early diagnosis of cancer.The main innovative results are as follows:(1)Using the AAO template and physical vapor deposition(PVD),an ordered nanopore array was prepared as the SERS substrate.The proposed SERS substrate avoids the shortcomings of the traditional silver substrate(i.e.vulnerability towards oxidation),and significantly improves the SERS enhancement and the uniformity of SERS detection.(2)A gold core-silver shell structured SERS nanoprobe was prepared and its SERS activity was explored.The results showed that the introduction of a silver shell helps to improve the SERS effect and protect the Raman molecules.The gold core silver shell SERS probe was modified with aptamers to recognize HER2 and SKBR3 exosomes.(3)A SERS microfluidic detection platform based on the nanopore array and gold core silver shell SERS probe is proposed.The SERS substrate in the microfluidic chip was obtained by layer-by-layer assembly.The chip has the advantages of good repeatability,high detection sensitivity,simple operation and low cost,and provides an efficient strategy for early diagnosis of cancer.Using a sandwich-type immunodetection strategy,first,quantitative detection of HER2 was achieved,the limit of detection(LOD)was 10μg/m L.Then,quantitative detection of SKBR3 exosomes in PBS and serum were realized.The detection limits were 4.32×10~3/μL in PBS,and 5.78×10~3/μL in serum.