Photochemical Synthesis of Porous CuFeSe2/Au Heterostructured Nanospheres as SERS Sensor for Ultrasensitive Detection of Lung Cancer Cells and Their Biomarkers

Rapid and sensitive identification of tumor biomarker or cancer cells in their nascent stage based on surface-enhanced Raman scattering (SERS) is still an attractive challenge due to the low molecular affinity for the metal surface, the complexity of the sample, and low-efficiency use of hot spots in one- or two-dimensional geometries. Here, we demonstrated a novel kind of renewable CuFeSe2/Au heterostructured nanospheres that are hierarchically porous for specific and sensitive detection of lung cancer biomarkers of aldehydes and lung cancer cells. The heterostructured nanospheres were constructed by loading an Au shell formed by photoreduction on the CuFeSe2 frameworks. P-aminothiophenol (4-ATP) as a Raman-active probe molecule was first grafted on CuFeSe2/Au nanospheres, and then the gaseous aldehyde molecules were sensitively bonded onto the nanospheres by formation of a C=N bond with a detection limit of 1.0 ppb. Moreover, the resulting folic acid (FA)-conjugated nanospheres have a high SERS activity to Rhodamine B isothiocyanate (RBITC), which can be used to specifically recognize and sensitively detect the A549 cells. Our study suggested that the synthesized renewable CuFeSe2/Au heterostructured nanospheres as a multimodal platform could find a wide range of applications in the fields of medicine, biotechnology, and environmental sciences.