Abstract
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.