Preparation of mitochondria-targeted gold nanoprobes and their SERS application in the detection of DON-induced apoptosis.

Deoxynivalenol (DON) is a fungal toxin and commonly found in cereals. Its cytotoxicity occurs through the mitochondria-mediated apoptotic pathway. In this paper, a surface-enhanced Raman spectroscopy (SERS) method has been utilized for monitoring of biomolecules in the mitochondrial region. Gold nanostars (AuNSs) were first modified with triphenylphosphine (TPP). It could realize mitochondria targeting while serving as the SERS substrate to enhance the Raman spectra during the dynamic processes of intracellular substances. Results showed that AuNSs-TPP had good physiological stability and less cytotoxicity. DON was then used to establish the apoptosis model of HepG2 cells. SERS spectra of cells with different DON incubation times using AuNSs-TPP were monitored. The specific Raman peaks corresponded to different intracellular substances. The spectra revealed that the high-level structure of proteins in mitochondria was the first to be disrupted, followed by the disintegration of the double-helix structure of DNA and then the increase of glycogen. Besides, SERS spectra for the cells pretreated with resveratrol (Res) verified its inhibitory effect on apoptosis in HepG2 cells. This AuNSs-TPP-based SERS assay realized the in situ monitoring of DON-induced apoptosis. It has prospects for research on mycotoxin-induced cell damage in the field of food safety.