바이오마커와 독소단백질의 고감도 정량검출을 위한 나노플라즈모닉스 바이오센서

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a powerful spectroscopic technique capable of detecting and identifying trace amounts of chemicals based on their unique vibrational characteristics. To date, numerous studies have been performed for the production of SERS-active substrates including solid supports and colloid nanoparticles. Herein, hot spots play a key role for signal amplification. In this work, many different types of SERS substrates including colloid nanoparticles and two-dimensional solid substrates have been investigated. First, two-dimensional nano-structured substrates for rapid and reproducible SERS detection have been developed. In this case, Au colloidal nanoparticles are combined with two-dimensional Au substrates. Here, two different types of hot spots can be generated. One is emerged among aggregated particles on gold substrates, and the other is emerged from the edges between nanoparticles and plane substrates. Thus, the SERS-based immunoassay using nanoparticles carried on a gold substrate is much more sensitive than that performed on a glass substrate. SERS-active immunocomplexes can be formed through the immunoreaction between antibodies and antigens. Such a discovery opens up a new SERS-based immunoassay method for ultrasensitive biomarker detection. On the other hand, encoded nanoparticles can be used as effective nano tags for biological assays in solution. Compared with microarray-based SERS detection methods, the ‘suspension array’ offers greater flexibility, more rapid assay and good reproducibility. Moreover, the use of magnetic beads offers a number of benefits including ease of separation, aggregation induction and redispersion. When coated with ligand molecules (antibodies or aptamers), the magnetic beads are useful for the capture and separation of various targets. Unwanted sample constituents can be washed away by a simple magnetic separation step. In this work, the SERS-based immunoassay using magnetic beads-based suspension array has been also performed. Designing innovative SERS substrates involves fabricating highly reproducible and controllable “hot spots” for huge enhancement of electromagnetic (EM) field. The optimized SERS substrates make it possible to carry out the quantitative and reproducible detection of chemical and biological species including biomarker protein, food toxin, virus, bacteria and so on. This SERS-based detection technology is expected to provide a new sensing platform with high sensitivity in many important areas including environmental monitoring, health care, food safety, and security.