A novel tricationic fullerene C60 as broad-spectrum antimicrobial photosensitizer: mechanisms of action and potentiation with potassium iodide

Agazzi, Maximiliano L.; Durantini, Javier E.; Quiroga, Ezequiel D.; Alvarez, M. Gabriela; Durantini, Edgardo N.

doi:10.1007/s43630-021-00021-1

Cited by 24 publications

(23 citation statements)

References 65 publications

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“…The PDI of E. coli sensitized by PZnTEP was also evaluated in presence of KI. This inorganic salt has shown impressive bacterial killing when combined with PDI [ 26 , 27 , 39 , 40 , 41 , 42 ]. The improved therapy results from the formation of a triiodide anion after reaction of iodide anion with traces amounts of O 2 ( 1 Δ g ) ( Scheme S1 ) [ 26 , 43 ].…”

Section: Resultsmentioning

confidence: 99%

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Antimicrobial Photosensitizing Material Based on Conjugated Zn(II) Porphyrins

et al. 2022

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The widespread use of antibiotics has led to a considerable increase in the resistance of microorganisms to these agents. Consequently, it is imminent to establish new strategies to combat pathogens. An alternative involves the development of photoactive polymers that represent an interesting strategy to kill microbes and maintain aseptic surfaces. In this sense, a conjugated polymer (PZnTEP) based on Zn(II) 5,10,15,20-tetrakis-[4-(ethynyl)phenyl]porphyrin (ZnTEP) was obtained by the homocoupling reaction of terminal alkyne groups. PZnTEP exhibits a microporous structure with high surface areas allowing better interaction with bacteria. The UV-visible absorption spectra show the Soret and Q bands of PZnTEP red-shifted by about 18 nm compared to those of the monomer. Also, the conjugate presents the two red emission bands, characteristic of porphyrins. This polymer was able to produce singlet molecular oxygen and superoxide radical anion in the presence of NADH. Photocytotoxic activity sensitized by PZnTEP was investigated in bacterial suspensions. No viable Staphylococcus aureus cells were detected using 0.5 µM PZnTEP and 15 min irradiation. Under these conditions, complete photoinactivation of Escherichia coli was observed in the presence of 100 mM KI. Likewise, no survival was detected for E. coli incubated with 1.0 µM PZnTEP after 30 min irradiation. Furthermore, polylactic acid surfaces coated with PZnTEP were able to kill efficiently these bacteria. This surface can be reused for at least three photoinactivation cycles. Therefore, this conjugated photodynamic polymer is an interesting antimicrobial photoactive material for designing and developing self-sterilizing surfaces.

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Section: Resultsmentioning

confidence: 99%

“…Samples were irradiated under aerobic conditions with light at 455–800 nm (44 mW/cm 2 , Figure S2A ). The progress of the reaction was monitored by following the increase of the absorbance at λ = 560 nm ( Figure S4 ) [ 26 ].…”

Section: Methodsmentioning

confidence: 99%

Antimicrobial Photosensitizing Material Based on Conjugated Zn(II) Porphyrins

et al. 2022

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“…It was reported that the efficacy of PDI mediated by methylene blue was considerably increased in S. aureus and E. coli after the addition of KI [ 48 ]. Additionally, the PDI of bacteria and yeast cells sensitized by cationic fullerenes was potentiated by iodide anions [ 33 , 49 , 50 ]. Even KI was able to enhance the photokilling of microorganisms induced by BODIPYs, which have a low production of O 2 ( 1 Δ g ) [ 35 ].…”

Section: Resultsmentioning

confidence: 99%

“…The experiment was carried out as described above for the photodecomposition of Trp, irradiating the samples with visible light (350–800 nm). The generation of iodine was studied by UV–visible spectroscopy following the absorbance at 360 nm after different irradiation times (0–50 min) [ 36 , 50 ]. A solution of Lugol was used as a positive control.…”

Section: Methodsmentioning

confidence: 99%

Porphyrin–Schiff Base Conjugates Bearing Basic Amino Groups as Antimicrobial Phototherapeutic Agents

et al. 2021

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New porphyrin–Schiff base conjugates bearing one (6) and two (7) basic amino groups were synthesized by condensation between tetrapyrrolic macrocycle-containing amine functions and 4-(3-(N,N-dimethylamino)propoxy)benzaldehyde. This approach allowed us to easily obtain porphyrins substituted by positive charge precursor groups in aqueous media. These compounds showed the typical Soret and four Q absorption bands with red fluorescence emission (ΦF ~ 0.12) in N,N-dimethylformamide. Porphyrins 6 and 7 photosensitized the generation of O2(1Δg) (ΦΔ ~ 0.44) and the photo-oxidation of L-tryptophan. The decomposition of this amino acid was mainly mediated by a type II photoprocess. Moreover, the addition of KI strongly quenched the photodynamic action through a reaction with O2(1Δg) to produce iodine. The photodynamic inactivation capacity induced by porphyrins 6 and 7 was evaluated in Staphylococcus aureus, Escherichia coli, and Candida albicans. Furthermore, the photoinactivation of these microorganisms was improved using potentiation with iodide anions. These porphyrins containing basic aliphatic amino groups can be protonated in biological systems, which provides an amphiphilic character to the tetrapyrrolic macrocycle. This effect allows one to increase the interaction with the cell wall, thus improving photocytotoxic activity against microorganisms.

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“…In the aPDI context, it has been described that iodide anion (I − ) can boost the photodynamic killing of bacterial and fungal species [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. This is especially appealing for anionic photosensitizers, like RB , which are particularly inefficient against Gram-negative bacteria in solution [ 57 ].…”

Section: Introductionmentioning

confidence: 99%

Photodynamic Inactivation of Pseudomonas aeruginosa by PHEMA Films Loaded with Rose Bengal: Potentiation Effect of Potassium Iodide

et al. 2021

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Four formulations have been used to produce different poly(2-hydroxyethyl methacrylate) (PHEMA) thin films, containing singlet oxygen photosensitizer Rose Bengal (RB). The polymers have been characterized employing Thermogravimetric Analysis (TGA), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and UV-vis Absorption Spectroscopy. When irradiated with white light (400–700 nm) films generated singlet oxygen (1O2), as demonstrated by the reactivity with 1O2 trap 9,10-dimethylanthracene (DMA). Material with the highest RB loading (polymer A4, 835 nmol RB/g polymer) was able to perform up to ten cycles of DMA oxygenation reactions at high conversion rates (ca. 90%). Polymer A4 was also able to produce the complete eradication of a Pseudomonas aeruginosa planktonic suspension of 8 log10 CFU/mL, when irradiated with white light (total dose 72 J/cm2). The antimicrobial photodynamic effect was remarkably enhanced by adding potassium iodide (100 mM). In such conditions the complete bacterial reduction occurred with a total light dose of 24 J/cm2. Triiodide anion (I3−) generation was confirmed by UV-vis absorption spectroscopy. This species was detected inside the PHEMA films after irradiation and at concentrations ca. 1 M. The generation of this species and its retention in the matrix imparts long-lasting bactericidal effects to the RB@PHEMA polymeric hydrogels. The polymers here described could find potential applications in the medical context, when optimized for their use in everyday objects, helping to prevent bacterial contagion by contact with surfaces.

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A novel tricationic fullerene C60 as broad-spectrum antimicrobial photosensitizer: mechanisms of action and potentiation with potassium iodide

Cited by 24 publications

References 65 publications

Antimicrobial Photosensitizing Material Based on Conjugated Zn(II) Porphyrins

Antimicrobial Photosensitizing Material Based on Conjugated Zn(II) Porphyrins

Porphyrin–Schiff Base Conjugates Bearing Basic Amino Groups as Antimicrobial Phototherapeutic Agents

Photodynamic Inactivation of Pseudomonas aeruginosa by PHEMA Films Loaded with Rose Bengal: Potentiation Effect of Potassium Iodide

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