Silicon Nanowire-Based Surface-Enhanced Raman Spectroscopy Endoscope for Intracellular pH Detection

Very recently, one-dimensional nanowire (NW) sensors have attracted great attention as smart optical endoscopes to probe and manipulate intracellular biological processes. However, NWs often have limited optical response to the intracellular environment changes. In this work, a near-infrared nanowire optical endoscope for high-resolution intracellular pH detection was developed by integrating the advantages of silicon nanowires and surface-enhanced Raman spectroscopy (SERS). This optical endoscope has a high-resolution, sensitive response to local pH changes over the wide range of pH 4.0-9.0, an important range for most biological processes in cells, with high reproducibility, good reversibility, and at least one-week stability in an aqueous environment. The results indicate the great potential of a single SiNW SERS endoscope for intracellular pH monitoring.