As resistance of bacterial strains to antibiotics is a major problem, there is a need to look for alternative treatments. One option is antimicrobial photodynamic inactivation (aPDI). The pathogenic cells are targeted by a nontoxic photosensitizer while the surrounding healthy tissue is relatively unaffected. The photosensitizer is activated by light of t appropriate wavelength resulting in the generation of reactive oxygen species that are cytotoxic for the pathogens. In this work, the photosensitizer TMPyP and silver nanoparticles (AgNPs) were investigated for their synergistic antibacterial effect. We tested these two substances on two bacterial strains, methicillin-resistant Staphylococcus aureus 4591 (MRSA) and extended-spectrum beta-lactamases-producing Klebsiella pneumoniae 2486 (ESBL-KP), to compare their effectiveness. The bacteria were first incubated with TMPyP for 45 min or 5 h, then irradiated with a LED source with the total fluence of 10 or 20 J/cm2 and then placed in a microbiological growth medium supplemented with AgNPs. To accomplish the synergistic effect, the optimal combination of TMPyP and AgNPs was estimated as 1.56-25 μM for TMPyP and 3.38 mg/l for AgNPs in case of MRSA and 1.56-50 μM for TMPyP and 3.38 mg/l for AgNPs in case of ESBL-KP at 45 min incubation with TMPyP and fluence of 10 J/cm2. Longer incubation and/or longer irradiation led to a decrease in the maximum values of the photosensitizer concentration to produce the synergistic effect. From this work it can be concluded that the combination of antimicrobial photodynamic inactivation with a treatment including silver nanoparticles could be a promising approach to treat bacterial infection.
- MeSH
- antibakteriální látky farmakologie MeSH
- antiinfekční látky * farmakologie MeSH
- fotochemoterapie * metody MeSH
- fotosenzibilizující látky farmakologie MeSH
- Klebsiella pneumoniae MeSH
- kovové nanočástice * MeSH
- methicilin rezistentní Staphylococcus aureus * MeSH
- porfyriny * farmakologie MeSH
- rezistence na methicilin MeSH
- stříbro farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
Photodynamic therapy (PDT) is one of the treatments for cancer. This therapy uses a combination of a photosensitizer (PS), light irradiation, and oxygen O2, which is converted to cytotoxic 1O2 and other forms of reactive oxygen species (ROS), causing selective damage to the target tissue. In this work, we studied effect of two porphyrin photosensitizers TMPyP and ZnTPPS4 at three different concentrations (0.25, 0.5, 5μM) after two irradiation doses (5 and 25 J/cm2). Photodynamic efect of TMPyP and ZnTPPS4 were confirmed by a battery of in vitro tests including MTT, reactive oxygen species (ROS) production and mitochondrial membrane potential test (MMP). Morphological changes of the cells before and after treatment were imaged by atomic force microscopy (AFM). The most effective combination of irradiation dose and concentration for both PSs showed a concentration of 5 μM and a irradiation dose of 25 J/cm2 in both cell cultures.
Photodynamic therapy (PDT) uses photosensitive substance to provoke a cytotoxic reaction causing a cell damage or cell death. The substances, photosensitizers, are usually derivates of porphyrine or phtalocyanine. Photosensitizers must be activated by light in order to produce reactive oxygen species, mainly singlet oxygen. Sonodynamic therapy (SDT) utilizes ultrasound to enhance a cytotoxic effects of compounds called sonosensitizers. In this study we investigated photodynamic and sonodynamic effect of chloraluminium phtalocyanine disulfonate (ClAlPcS(2)) on HeLa cells. DNA damage, cell viability and reactive oxygen species (ROS) production were assessed to find whether the combination of PDT and SDT inflicts HeLa cells more than PDT alone. We found that the combined therapy increases DNA fragmentation, enhances ROS production and decreases cell survival. Our results indicate that ClAlPcS(2) can act as a sonosentitiser and combined with PDT causes more irreversible changes to the cells resulting in cell death than PDT alone.
- MeSH
- fotochemoterapie * MeSH
- HeLa buňky MeSH
- indoly * MeSH
- léky antitumorózní - screeningové testy MeSH
- lidé MeSH
- organokovové sloučeniny * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Apart from being a powerful medical imaging technique ultrasound can also be used as a therapeutic modality. In vitro sonication experiments performed on cultured cells are one of primary research methods. However present sonication protocols and methods meet many effects influencing the final ultrasound dose experienced by the sonicated samples. The main aim of this study is to assess the influence of laboratory glass and plastics on ultrasound field parameters during in vitro sonication experiments. We performed measurements of ultrasound field parameters (ultrasound intensity and its local distribution) behind commonly used laboratory glass and plastics placed into the far field region of an ultrasound transducer. We tested the influence of several types of culture dishes, culture plates and sample test tubes. Culture dishes reduced ultrasound intensity by tens of percent but did not affect the shape of ultrasound field. 6-well plate reduced ultrasound intensity only by 5 %. Culture plates with well diameter smaller than the diameter of the main lobe of ultrasound beam focus ultrasound energy. Laboratory glass and plastics with curved surface also focus ultrasound energy. We proved that laboratory glass and plastics considerably affect ultrasound field parameters. Thus sonicated samples are exposed to different ultrasound conditions compared to those reported in some of scientific articles. Rest of factors (standing waves formation, streaming, cell mixing, heating and homogeneity of ultrasound field in terms of near and far ultrasound field) affecting the ultrasound field parameters experienced by sonicated samples also need to be studied further.
- MeSH
- plastické hmoty MeSH
- sklo MeSH
- techniky in vitro MeSH
- ultrazvukové vlny * MeSH
- výzkum MeSH
- Publikační typ
- práce podpořená grantem MeSH
