Fluorescence-SERS dual-signal probes for pH sensing in live cells

The activity of many cells is closely related to the pH of their internal environment, and the increase of intracellular pH value is a common feature of many drug-resistant tumors. The intracellular pH needs to be determined as the research basis when studying the intracellular transport protein and ion concentration changes. Nanomaterials are now widely used as the effective imaging and drug delivery vehicles, but it remains to be studied as a sensor for intracellular environment. Based on this, we have constructed a nanoprobe with fluorescence and surface-enhanced Raman scattering (SERS) dual-signal for sensing intracellular pH. The principle of this strategy is to construct fluorescence-SERS dual-signal nanoprobes by modifying pH-responsive fluorescent probes and SERS reporter molecules on the surface of gold nanorods (AuNRs) with the core-shell structure. The fluorescence-SERS dual response of the nanoprobe to pH can be achieved by investigating the fluorescence and SERS spectra of nanoprobes at different pH. Moreover, by incubating the nanoprobes into different cells, different double-signal response results can be obtained, thereby achieving intracellular pH sensing. The nanoprobe has dual responsiveness to fluorescence and SERS, which makes up for many of the deficiencies of single-signal probes, and realizes high sensitivity, accuracy and stability of intracellular pH detection. It is expected to be widely applied in the fields of medicine, chemistry and biology.