Lung cancer is the leading cause of cancer death worldwide. Its early detection 
is of paramount importance for diagnosis, classification, treatment, and 
improvement of survivorship. However, current methods are not sensitive enough 
to detect lung cancer in its nascent stage. We reported an aptamer-Ag-Au 
shell-core nanostructure-based surface-enhanced Raman scattering (SERS) assay 
for sensitive and specific detection, and near-infrared (NIR) photothermal 
therapy of lung adenocarcinoma cells (A549 cells). The nanostructures target the 
cells with high affinity and specificity via the specific interaction between 
the aptamer (a 45-base oligonucleotide) and the cell, and distinguish A549 cells 
from other types of cancer cells (HeLa and MCF-7 cells) and subtypes of lung 
cancer cells (NCI-H157, NCI-H520, NCI-H1299, and NCI-H446 cells). The 
nanostructures have a high capability to absorb NIR irradiation and are able to 
perform photothermal therapy of the cells at a very low irradiation power 
density (0.20 W cm(-2)) without destroying the healthy cells and the surrounding 
normal tissues. In addition, the nanostructures exhibit a high SERS activity. 
Based on the SERS signal of the labeled Raman reporter (Rh6G molecules), we can 
specifically detect A549 cells at a very low abundance (~10 cells per mL) and 
monitor the therapy process of the cancer cells. Therefore, this 
nanostructure-based SERS assay has great potential in specific recognition, 
sensitive detection, and effective photothermal therapy of lung cancer.