(260q) Micro-Raman Phonon-Energy Mapping of Cell/Graphene Interface for Non-Invasive Cancer Diagnosis Via Ultrasensitive Cellular Potential and Activity Measurements

Authors: 
Berry, V., University of Illinois at Chicago
Keisham, B., University of Illinois at Chicago
Cole, A., University of Illinois at Chicago
Mehta, A., University of Illinois at Chicago
Nguyen, P., Kansas State University
Ultra-sensitive detection of signals of cancer and the monitoring of treatment efficacy is critical for patient care. Here we show a graphene-based Raman biosensor capable of sensitively differentiating cancerous (Glioblastoma Multiforme, GBM) from normal cells (Astrocytes) at single cell resolution. Examining the modification of phonon vibrations induced by cellular doping on graphene via Raman Spectroscopy, we found sensitive responses exhibited by GBM cells (highly p doped with a significant 2D peak shift of approximately 6±0.5 cm-1) and Astrocytes (p doped with 2D peak shift of approximately 2.2±0.2 cm-1). The high quantum capacitance of graphene led to a change in the doped carrier concentration and a shift in the phonon energy; which provides a cell surface potential of ~310 mV, twice the potential exerted by astrocytes on graphene. This is attributed to the acidic character and increased surface electronegativity of the GBM cancer cells in comparison to the astrocytes. These results show that the process can be applied to other cancer cell types, particularly metastatic tumors that circulate through the blood stream as a pathological assessment tool. The high sensitivity of the device can be leveraged to characterize different grades of cancer, as in the case of brain tumors, based on their malignancy and aggressive nature.