Uptake and release of photosensitizers in a hydrogel for applications in photodynamic therapy: the impact of structural parameters on intrapolymer transport dynamics

Glass, Sarah; Rüdiger, Tom; Griebel, Jan; Abel, Bernd; Schulze, Agnes

doi:10.1039/c8ra08093c

Cited by 12 publications

(22 citation statements)

References 47 publications

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“…To determine the effects of the different isomeric substitution patterns of the pyridinium groups on in vitro singlet oxygen production, which was conceivable based on the identified differences in B band absorption coefficients, hypsochromic shift and photostability, we performed the ABDA test as previously described [ 44 , 45 ]. For meta -TMPyP , the half-maximal reduction of fluorescence (EC 50 ) was calculated to be reached only slightly earlier (18 s) than for para -TMPyP (5.24 vs. 5.54 min, p = 0.02), with a small, but significant difference in fluorescence detected only at 4 min reaction time ( Figure 4 , p < 0.01).…”

Section: Resultsmentioning

confidence: 99%

“…The generation of singlet oxygen was analyzed using the fluorescent dye, 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), as described previously [ 44 ]. ABDA reacts selectively with singlet oxygen to a nonfluorescent endo-peroxide product.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, TMPyP has an absorption maximum in the wavelength range around 420 nm and is therefore particularly suitable for superficial photodynamic treatment, for example of infected wounds. Modified translucent hydrogels can serve as a carrier system, allowing the release of PSs under local illumination [ 44 , 45 ] . This, and the increasing availability of inexpensive lasers and light-emitting diodes (LED) for optical excitation [ 46 , 47 ], may enable applications of PDT both in cancer therapy and against infections with multidrug-resistant bacteria.…”

Section: Introductionmentioning

confidence: 99%

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The Meta-Substituted Isomer of TMPyP Enables More Effective Photodynamic Bacterial Inactivation than Para-TMPyP In Vitro

et al. 2022

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Porphyrinoid-based photodynamic inactivation (PDI) provides a promising approach to treating multidrug-resistant infections. However, available agents for PDI still have optimization potential with regard to effectiveness, toxicology, chemical stability, and solubility. The currently available photosensitizer TMPyP is provided with a para substitution pattern (para-TMPyP) of the pyridinium groups and has been demonstrated to be effective for PDI of multidrug-resistant bacteria. To further improve its properties, we synthetized a structural variant of TMPyP with an isomeric substitution pattern in a meta configuration (meta-TMPyP), confirmed the correct structure by crystallographic analysis and performed a characterization with NMR-, UV/Vis-, and IR spectroscopy, photostability, and singlet oxygen generation assay. Meta-TMPyP had a hypochromic shift in absorbance (4 nm) with a 55% higher extinction coefficient and slightly improved photostability (+6.9%) compared to para-TMPyP. Despite these superior molecular properties, singlet oxygen generation was increased by only 5.4%. In contrast, PDI, based on meta-TMPyP, reduced the density of extended spectrum β-lactamase-producing and fluoroquinolone-resistant Escherichia coli by several orders of magnitude, whereby a sterilizing effect was observed after 48 min of illumination, while para-TMPyP was less effective (p < 0.01). These findings demonstrate that structural modification with meta substitution increases antibacterial properties of TMPyP in PDI.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Meta-Substituted Isomer of TMPyP Enables More Effective Photodynamic Bacterial Inactivation than Para-TMPyP In Vitro

et al. 2022

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“…The hydrogel loading was performed as described elsewhere. 37 In short, the hydrogels for antimicrobial testing were loaded with TMPyP and THPTS, respectively. The 6 mm hydrogel discs ( V swollen hydrogel ≈ 10 μl) were immersed in an 800 μM photosensitizer solution for 48 h. 100 μl solution per disc were applied.…”

Section: Methodsmentioning

confidence: 99%

Photosensitizer-loaded hydrogels for photodynamic inactivation of multirestistant bacteria in wounds

et al. 2021

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“…Photosensitizers produce antimicrobial singlet oxygen when irradiated with light, and are applied in photodynamic therapy [22,23,24]. In former studies, a reversible loading of photosensitizers was investigated in UV-cured hydrogels [21,25]. Previously, irreversible immobilization of photoactive drug was not possible using UV polymerization [21].…”

Section: Introductionmentioning

confidence: 99%

Controlled Electron-Beam Synthesis of Transparent Hydrogels for Drug Delivery Applications

et al. 2019

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In this study, we highlight hydrogels prepared by electron-beam polymerization. In general, the electron-beam-polymerized hydrogels showed improved mechanical and optical transmittances compared to the conventional UV-cured hydrogels. They were more elastic and had a higher crosslinking density. Additionally, they were transparent over a broader wavelength range. The dependence of the mechanical and optical properties of the hydrogels on the number of single differential and total irradiation doses was analyzed in detail. The hydrogels were prepared for usage as a drug delivery material with methylene blue as a drug model. In the first set of experiments, methylene blue was loaded reversibly after the hydrogel synthesis. Electron-beam-polymerized hydrogels incorporated twice as much methylene blue compared to the UV-polymerized gels. Furthermore, the release of the model drug was found to depend on the crosslinking degree of the hydrogels. In addition, electron-beam polymerization enabled the irreversible binding of the drug molecules if they were mixed with monomers before polymerization.

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Uptake and release of photosensitizers in a hydrogel for applications in photodynamic therapy: the impact of structural parameters on intrapolymer transport dynamics

Abstract: Different photoactive compounds were evaluated regarding their uptake and release in polymer hydrogels with respect to size, charge, and acidity.

Cited by 12 publications

References 47 publications

The Meta-Substituted Isomer of TMPyP Enables More Effective Photodynamic Bacterial Inactivation than Para-TMPyP In Vitro

The Meta-Substituted Isomer of TMPyP Enables More Effective Photodynamic Bacterial Inactivation than Para-TMPyP In Vitro

Photosensitizer-loaded hydrogels for photodynamic inactivation of multirestistant bacteria in wounds

Controlled Electron-Beam Synthesis of Transparent Hydrogels for Drug Delivery Applications

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