The aim of the present study was to evaluate the efficiency of photosensitisation induced by two photosensitizers, TMPyP and ClAlPcS2, tested in vitro on the tumor cell line MCF7. The oxidative damage of DNA in MCF-7 cells was analyzed by comet assay (CA) combined with Atomic Force Microscopy (AFM). The ability of detection of apoptotic response detected by Atomic Force Microscopy at the individual molecule level of DNA was successfully demonstrated; when DNA get damaged, cleavage to fragments caused by photodynamic treatment was directly visualized by AFM imaging of individual molecules. Its accuracy and reliability was validated through the comparison with traditional single cell agarose electrophoresis.
High resolution imaging of biological structures and changes induced by various agents such as drugs and toxins is commonly performed by fluorescence and electron microscopy (EM). Although high-resolution imaging is possible with EM, the requirements for fixation and staining of samples for image contrast severely limits the study of living organisms. Atomic force microscopy (AFM), on the other hand, is capable of simultaneous nanometer spatial resolution and piconewton force detection, allowing detailed study of cell surface morphology and monitoring cytomechanical information. We present a method that images and studies mechanically characterized cells using AFM. We used a HeLa cell line (cervix carcinoma cell), which is sensitive to photodynamic treatment (PDT); growth media as a scanning surrounding; atomic force microscopy NT-MDT Aura for cytomechanical measurement; and scanning electron microscope Hitachi Su 6600 for control images of the cells. The modulus of elasticity for intact and photodynamically damaged cells can indicate mechanical changes to the main properties of cells. Cell elasticity changes can provide information on the degree or value of cell damage, for example after PDT. Measurements were carried out on approximately sixty cells, including three independent experiments on a control group and on sixty cells in a photodamaged group. Cells before PDT show higher elasticity: the median of Young´s modulus on the nucleus was 35.283 kPa and outside of the nucleus 107.442 kPa. After PDT, the median of Young's modulus on the nucleus was 61.144 kPa and outside of the nucleus was 193.605 kPa.
- Publikační typ
- abstrakt z konference MeSH
Dentin of human teeth is a vital hydrated tissue. It is strongly sensitive to dehydration and drying that are commonly used in preparation of samples for scanning electron microscopy. Experience in examination of dentine surfaces of extracted human third molars using contact mode atomic force microscopy under moist conditions is described. The examined dentine surfaces are modified by laser radiation produced by a pulsed Nd:YAG laser that leads to sealing of open dentinal tubules under suitable conditions that are reached after covering dentine surfaces with dye agents. Out of four investigated dye agents erythrosin solution in water has been found the most suitable and the lower and upper limits of pulse energies for sealing of dentinal tubules have been set. Copyright (c) 2007 John Wiley & Sons, Ltd.
- MeSH
- dentin účinky léků účinky záření ultrastruktura MeSH
- erythrosin farmakologie MeSH
- financování organizované MeSH
- laserová terapie metody přístrojové vybavení MeSH
- leptání zubů metody MeSH
- lidé MeSH
- mikroskopie atomárních sil MeSH
- mikroskopie elektronová rastrovací MeSH
- permeabilita dentinu MeSH
- povrchové vlastnosti MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- hodnotící studie MeSH
Závěrečná zpráva o řešení grantu Interní grantové agentury MZ ČR
64 l. : il., tab. ; 30 cm
Determination of characteristics of Nd:YAG laser irradiation for the occluding of exposed dentinal tubules of extracted human molars. Characterisation of surface morphology of exposed dentin both irradiated and not irradiated by Nd:YAG laser by ScanningElectron Microscopy (SEM) and Atomic Force Microscopy (AFM). Determination of the usefulness of Atomic-force microscopy to the characterization of morphology of exposed dentin of extracted human teeth.
Stanovení fyzikálních charakteristik Nd:YAG laseru pro modifikaci povrchové morfologie exponovaného dentinu lidských extrahovaných molárů ve smyslu tubulové okluze. Vyhodnocení povrchové morfologie exponovaného dentinu ozářeného a neozářeného Nd:YAG laserem pomocí SEM (Scanning Electron Microscopy) a AFM (Atomic Force Microscopy). Zhodnocení přínosu AFM pro vyšetření morfologie exponovaného dentinu lidských extrahovaných zubů.
