Recently, the team led by Prof. HUANG Qing at the Institute of Intelligent Machines, Hefei Institutes of Physical Science (HFIPS) developed a novel biosensor based on aptamer-combined surface-enhanced Raman spectroscopy (SERS) to achieve the inflammatory microRNA-122 (miR-122) detection in cell-secreted exosomes.
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.
In general, this method could provide easy and early diagnosis for analyzing hepatic inflammation cases at the clinical level.
This research was supported by the National Natural Science Foundation of China and China Scholarship Council.
Figure 1. Schematic illustration of SERS detection of exosomal miR-122 in mice exposed to X-ray irradiation (adopted from the online published paper in ACS Applied Bio Materials) (Image by Muhammad)