Gold nanoflower‐based surface‐enhanced Raman probes for pH mapping of tumor cell microenviroment

Objectives Early diagnosis of tumour cells is critically important for cancer treatment. Given that the tumour environment is slightly acidic, the pH value of the cell environment can be used as a criterion for tumour diagnosis. However, mapping pH in the cell environment with high resolution, high sensitivity and accuracy remains challenging. Materials and Methods Based on gold nanoflower as surface‐enhanced Raman scattering (SERS) substrate loading with p‐mercaptobenzoic acid (MPA) as pH‐responsive Raman reporter, a new SERS nanoprobe for pH mapping was developed. Results This probe showed a characteristic Raman spectrum signal in response to the different pH in solutions or cells. The signal intensity is positively correlated to the pH value. Moreover, this probe is self‐correctable, which can help eliminate the influence of probe concentration on the accuracy of pH measuring. Conclusions We demonstrate the pH mapping of cell environment using the probe, which can be used to distinguish normal cells and tumour cells. This method may provide a new imaging tool for early diagnosis of cancer.