Despite the significant advances of imaging techniques nowadays, accurate diagnosis of bacterial infections and real‐time monitoring the efficacy of antibiotic therapy in vivo still remain huge challenges. Herein, a self‐assembling peptide (FFYEGK) and vancomycin (Van) antibiotic molecule co‐modified gadolinium (Gd) MRI nanoaggregate probe (GFV) for detecting Staphylococcus aureus (S. aureus) infection in vivo and monitoring the treatment of S. aureus‐infected myositis by using daptomycin (Dap) antibiotic as model are designed and fabricated. The as‐prepared GFV probe bears Van molecules, making itself good bacteria‐specific targeting, and the peptide in the probe can enhance the longitudinal relaxivity rate (r1) after self‐assembly due to the π–π stacking. The study showed that, based on the GFV probe, bacterial infections and sterile inflammation can be discriminated, and as few as 105 cfu S. aureus can be detected in vivo with high specificity and accurately. Moreover, the T1 signal of GFV probe at the S. aureus‐infected site in mice correlates with the increasing time of Dap treating, indicating the possibility of monitoring the efficacy of antibacterial agents for infected mice based on the as proposed GFV probe. This study shows the potential of GFV probe for diagnosis, evaluation, and prognosis of infectious diseases in clinics.

No 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.