Quantitative proteomic analysis of HeLa cells in response to biocompatible Fe2C@C nanoparticles: 16O/18O-labelling & HPLC-ESI-orbit-trap profiling approach.

The effective detection of molecular biomarkers, such as proteins, lipids, carbohydrates, and pathogens, in a living body is a huge challenge in the field of nanomedicine. Here, we have investigated the comparative quantitative proteomics analysis of the molecular response of HeLa cells to biocompatible Fe2C@C nanoparticles (NPs) using 16O/18O isotopic labelling of the cell culture. The relative binding efficiency of proteins to Fe2C@C NPs was calculated. HPLC-ESI-orbit-trap analysis found 51 differentially expressed proteins, out of which 23 were over-expressed and 28 down-regulated. This study showed that Fe2C@C NPs alter the expression of the proteins involved in endocytosis, cell-cycle regulation, and cell membrane protrusion. Further, the quantification and validation of the mass spectrometry (MS) results was successfully confirmed by western blot analysis of cytochrome C. The change in the expression of proteins can be useful for early stage disease diagnoses and the development of tailored therapeutic strategies. This study is the first large-scale characterization of low abundance proteins on Fe2C@C NPs, providing the biochemical basis for the assessment of the suitability of magnetic NPs as biomedical markers and emerging functional probes.