Supramolecular pyrrole radical cations for bacterial theranostics

Area of Science:

• Supramolecular chemistry
• Materials science
• Antimicrobial research

Background:

• Emerging antibiotic resistance necessitates novel antibacterial agents with unique structures.
• Positively charged organic groups (e.g., ammonium, guanidine) show promise for targeting bacterial membranes.
• Integrating imaging modalities with antibacterial agents is crucial for precise therapy, but often involves complex synthesis.

Purpose of the Study:

• To develop a novel class of positively charged, deep-red fluorescent antibacterial agents.
• To explore their utility in imaging-guided antibacterial therapy and theranostics.
• To establish a new core skeleton for combating antibiotic-resistant bacteria.

Main Methods:

• Simple mixing of pyrroles and cucurbit[7]uril (CB[7]) in water under ambient conditions.
• Preparation of positively charged supramolecular pyrrole radical cations (P˙⁺-CB[7]).
• Evaluation of P˙⁺-CB[7] for bacterial imaging, killing, and in vivo studies.

Main Results:

• Successfully synthesized readily available, deep-red fluorescent P˙⁺-CB[7].
• Demonstrated selective imaging and killing of live Gram-positive bacteria with high biocompatibility.
• Showcased imaging of drug-killed Gram-negative bacteria and in vivo monitoring of bacterial phagocytosis in zebrafish.

Conclusions:

• Deep-red fluorescent pyrrole radical cations represent a novel core skeleton for antibacterial agents.
• P˙⁺-CB[7] show significant potential for bacterial theranostics, combining imaging and therapeutic capabilities.
• This approach offers a promising strategy for addressing the challenge of antibiotic resistance.