Bacteria‐Targeted MRI Probe‐Based Imaging Bacterial Infection and Monitoring Antimicrobial Therapy In Vivo

Abstract

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.

Molecularly Stimuli-Responsive Self-Assembled Peptide Nanoparticles for Targeted Imaging and Therapy

“…Vancomycin specifically binds to the d -Ala- d -Ala sequence in Gram-positive bacterial walls. As a result, various bacteria-specific diagnostic and therapeutic SAPs have been developed. , Wang et al designed a chitosan-peptide conjugate (CPC), which contained a chitosan backbone, an enzyme-cleavable peptide with a PEG terminal, and an antibacterial peptide (KLAK) (Figure A). Under the function of gelatinase, CPC transformed from nanoparticles into nanofibers.…”

“…As a magnetic resonance supramolecular contrast agent, it improved the inherent resolution of diagnostic imaging. Li et al 145 designed a T1-weighted MRI probe (GFV) based on the strategy of supramolecular self-assembly. The antibiotic molecule vancomycin in the probe targeted against Staphylococcus aureus.…”

An Ag2S@ZIF-Van nanosystem for NIR-II imaging of bacterial-induced inflammation and treatment of wound bacterial infection

“…9,10 Common traditional detection techniques for diagnosing bacterial infections in clinical settings, which include positron emission tomography 11 and radioactive labeling, 12 lack sufficient resolution and practicality. Newer technologies have been developed that allow bedside monitoring and direct targeting of invasive bacteria, such as magnetic resonance imaging (MRI), 13,14 photoacoustic imaging (PAI) 15,16 and nearinfrared fluorescence imaging (NIRFI). 17,18 NIR-II fluorescence imaging has attracted considerable attention for both preclinical and clinical applications due to its high sensitivity, high spatial and temporal resolution, and capability for deeptissue penetration.…”

Bacterial association with metals enables in vivo tracking of microbiota using magnetic resonance imaging

“…Despite widespread clinical use of magnetic resonance imaging (MRI), very little research has employed this technology to specifically detect bacteria [19][20][21][22][23] , and of these reports, virtually all relied on cell labels for contrast enhancement. To date, most MRI studies image bacterial infection indirectly by focusing on host inflammation 24,25 .…”