Antimicrobial activity of a quaternized BODIPY against Staphylococcus strains

Abstract

A novel BODIPY derivative was designed for biomedical applications. Its mono-quaternized structure ensured its water-solubility and suitable amphiphilicity. Showing no singlet oxygen generation to avoid damage to healthy cells, this new derivative proved to be an extremely promising antimicrobial agent, with activity equal or superior to ampicillin against MRS Staphylococcus strains with no short-term resistance issue. Its activity against MSS Staphylococcus strains was largely superior to those of ampicillin and reached the activity of vancomycin against MSS S. epidermidis. This latter result is in particular extremely promising for the treatment of hospital-acquired infections. Also the fluorescence properties of BODIPY allowed imaging of the uptake.

A Solution‐Processable meso‐Phenyl‐BODIPY‐Based n‐Channel Semiconductor with Enhanced Fluorescence Emission

“…BDY‐Ph‐Br crystallizes in the monoclinic P 2 1 /n space group, and the solid‐state structure reveals highly coplanar “boron‐dipyrromethene” core (C 9 BN 2 ) subunit with two ethyl groups (−C 2 H 5 ) lying nearly in the same plane with tilt angles of 1.57° and 9.16°. The “B−F” bond distances and “F−B−F”, “N−B−N”, and “N−N−F” bond angles match closely with those of previously reported BODIPY‐based π‐conjugated small molecules As shown in Figure B, the dihedral angle between the meso ‐phenyl group and the boron‐dipyrromethene π‐core was found to be 65.97°, which matches well with the computationally optimized geometries. This angle is large as compared to that of meso ‐thiophene substituted BODIPY (θ dihedral =48.8°) in BDY‐4T‐BDY, which doubtless reflects sterically encumbered nature of the six‐membered phenyl ring having “C−H” bonds pointing towards the BODIPY's 1,7‐positions.…”

Design of Photosensitizing Agents for Targeted Antimicrobial Photodynamic Therapy

“…As such it is commonly accepted that cationic PS such as methylene blue (MB) [49], toluidine blue O (TBO) [50] and other phenothiazinium derivatives [51], or cationic porphyrins [52,53] and phthalocyanines (Pc) [54] are well adapted to aPDT, showing both better efficiency and selectivity than neutral [55,56] or negatively-charged sensitisers [57][58][59][60] (Figure 2). Some other synthetic PS decorated with cationic groups to target bacterial infections include BODIPY [31,44,61], perinaphthenone [62] or perylene [35] derivatives. Anionic and neutral PS generally need to be chemically modified or vectorised to eliminate electrostatic repulsion with the bacterial membrane before use in aPDT.…”

“…In particular, following the major concerns around MDR bacteria, several new PS have been tested, adapted or developed for aPDT [30]. In this sense, positively charged PS appear promising for aPDT as they can interact electrostatically with the negatively charged bacterial membrane, and the synthesis of several PS functionalised with small cationic functional groups has been reported [31][32][33][34][35]. Nonetheless, two main concerns can arise from this strategy: (i) a poor target selectivity since such cationic species, due to electrostatic interactions with mammalian cells, lead to off-target damage, and (ii) the poor efficiency of aPDT against a certain type of pathogens, in particular Gram− bacteria and biofilms.…”

Fluorescent Probes for Live Cell Thiol Detection

“…In 2018, Fangfang Wang et al [167] presented a BODIPY-based fluorescent probe (Probe 54) for fast detection of intracellular mitochondrial thiols with high sensitivity and selectivity by introduction of a dual reactive group. Although BODIPY exhibits a number of advantages as a fluorophore, such as high fluorescence quantum yield, excellent photostability, and intense absorption of visible light [160,[168][169][170], utilization of BODIPY for building a BODIPY-based turn-on fluorescent probes is hindered by the hardship of completely quenching the original fluorescence of BODIPY leading to a high background and low sensitivity. To overcome the challenge, two quenching groups, a DNBS moiety and a nitroolefin moiety (-CH=CH-NO 2 ) were introduced to the BODIPY fluorophore.…”