Visualized SERS Imaging of Single Molecule by Ag/Black Phosphorus Nanosheets
Chenglong Lin, Shunshun Liang, Yusi Peng, Long Li, Yanyan Li, Zhengren Huang, Nguyen Viet Long, Xiaoying Luo, Jianjun Liu, Zhi‐Yuan Li, Yong Yang
Abstract
Trace detection is of great significance in the fields of environmental science, medical diagnosis, food safety and coronavirus detection [ 1 , 2 , 3 , 4 , 5 ]. With the need of reducing limit of detection (LOD), especially in the detection of biomarkers, the content of target in the clinical sample is usually much low, which may reach to pico-molar, femto-molar or even atto-molar level [ 6 ]. For instance, nanovesicles known as exosomes are secreted from a variety of tissues and circulate in biological fluids, which have been implicated in a number of human diseases, including cancer, and are becoming an appreciated fundamental aspect of tumor progression and metastasis [ 7 , 8 ]. But the tumor exosomes in the blood of patients may be single-vesicle level, which poses a great challenge to the existing detection methods [ 9 ]. Surface-enhanced Raman scattering (SERS) is a powerful tool to detect the spectral signals of molecules even at the single-molecular level [ 10 , 11 , 12 , 13 ]. It is widely used in biochemical analysis, such as pesticide residue analysis, virus detection, tissue tumor recognition, and even bioimaging due to its high sensitivity and molecular specificity [ 14 , 15 , 16 , 17 , 18 ]. However, there are still two obstacles: the fabrication of ultra-sensitive SERS substrates and the detection of single molecule (SM) over the surface of nanostructures, i.e., to achieve a single-molecule SERS-imaging [ 19 , 20 , 21 , 22 , 23 ].