Estrone Linked BODIPYs: Assessing Their Role as Sonosensitizers for Antimicrobial Applications

Area of Science:

• Photochemistry
• Materials Science
• Antimicrobial Therapy

Background:

• Sonodynamic therapy (SDT) utilizes ultrasound (US) to activate photosensitizers for treating deep-seated wounds and infections.
• Boron-dipyrromethene (BODIPY) derivatives are explored as photosensitizers for SDT applications.

Purpose of the Study:

• To synthesize and characterize estrone-linked BODIPY compounds as potential sonosensitizers.
• To investigate the structure-property relationships of these BODIPY derivatives for antimicrobial SDT.

Main Methods:

• Synthesis and characterization of estrone-linked BODIPY compounds with varying linker units (phenyl, thiophene).
• Spectroscopic analysis (absorption, emission) and TD-DFT calculations to understand electronic properties.
• Evaluation of singlet oxygen quantum yield and antibacterial activity against Escherichia coli (E. coli) using microbubble-assisted SDT.

Main Results:

• Estrone-substituted BODIPYs exhibited red-shifted absorption/emission spectra and larger Stokes shifts compared to a reference BODIPY.
• TD-DFT calculations revealed intramolecular charge transfer from the estrone linker to the BODIPY core.
• EBD-1 showed a high singlet oxygen quantum yield (~90%) and potent antibacterial efficacy, reducing E. coli viability by over 99.9%.

Conclusions:

• Estrone-linked BODIPYs are feasible sonosensitizers for antimicrobial SDT.
• The EBD-1 derivative demonstrates significant potential for developing novel therapeutic strategies against bacterial infections.