Novel SERS-Based Method Could Provide Easy and Early Diagnosis for Hepatic Inflammation

In this research, a label-free SERS-sandwich assay was developed to detect and evaluate a special exosomal miRNA, namely, miR-122, by combining aptamer-modified SERS tags and a magnetic NP-based miRNA capturing element. The SERS tags were composed of a thiolated aptamer, modified with additional G bases at the 3′ end, which was functionalized on Au shell NPs via Au-S bonds. The capturing element was prepared by anchoring a thiolated aptamer on magnetic NPs. For the recognition of target miRNA, the magnetic capturing element was initially exposed to the target, which captured the miRNA sequences via immunoreaction between recognition and target sequences. The NPs were separated using an external magnetic field, rinsed, and probed with SERS tags (Scheme). As a result, the target sequence was captured via sandwich formation. The enhanced Raman signal of adenine base at 3' end of SERS tag was used to calibrate the output.

This research utilized aptamer-combined SERS methodology to detect miRNA as the biomarker to evaluate radiation-induced organ injury. Another advantage of this method is the use of magnetic NPs. It can provide the additional facility of rapid and ready separation of analytes using an external magnetic field. This method is also applicable to evaluate the drug triggered liver inflammation via examining the exosomal miRNA as the biomarker.