Real-time and in-situ monitoring of Abrin induced cell apoptosis by using SERS spectroscopy

Abstract

Abrin is a cytotoxic protein isolated from seeds of leguminous plants and has become a potential bioterrorism weapon for its high toxity and difficult detection. In the early stage of poisoning, Arbin can damage cells and induce apoptosis. Raman spectroscopy is a molecular fingerprint that can identify and compare various intracellular substances. In this work, thiolated polyethylene glycol (mPEG-SH) and cell-penetrating peptide (TAT) modified 70–80 nm gold nanostars (AuNSs) have been developed as label-free Raman enhancement substrates to realize real-time and in-situ monitoring of toxin-induced adherent cell apoptosis. The changes for the surface-enhanced Raman scattering (SERS) spectra of cells before and after the damage (0 h, 2 h, 4 h, 8 h, 12 h and 24 h) of Abrin can be characterized via SERS spectroscopy. The intracellular substances at different time can be compared by using differential spectrum analysis and the cells in different states can be identified and distinguished by means of principal component analysis (PCA). The abundant spectral features in SERS spectra can also reveal the molecular dynamics during apoptosis. Results show that SERS spectroscopy provides a platform for in-situ monitoring of substance changes in adherent cells except detecting cell apoptosis induced by toxin in real-time, which achieves a more detailed and comprehensive understanding of the pathogenesis of toxins in molecular biology and provides a new idea for toxicology experiments.