AFM-based bivariate morphological discrimination of apoptosis induced by photodynamic therapy using photosensitizer-functionalized gold nanoparticles

Al-Majmaie, Rasoul; Kennedy, Eamonn; Al‐Rubeai, Mohamed; Rice, James H.; Zerulla, Dominic

doi:10.1039/c5ra15479k

Cited by 4 publications

(3 citation statements)

References 36 publications

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“…In recent years, membrane roughness has been noticed as a sensitive cellular feature related to various stimulations, including cytoskeletal alteration [ 12 ], blood toxicants [ 13 ], anti-cancer chemicals or nanoparticles [ 14 , 15 ], proteins related to neurodegenerative diseases [ 16 ], etc. In these works, the membrane roughness was obtained from AFM measurements, and therefore the results could be relevant to the membrane stiffness as well as the cytoskeletal organizations.…”

Section: Discussionmentioning

confidence: 99%

Membrane roughness as a sensitive parameter reflecting the status of neuronal cells in response to chemical and nanoparticle treatments

et al. 2016

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BackgroundCell membranes exhibit abundant types of responses to external stimulations. Intuitively, membrane topography should be sensitive to changes of physical or chemical factors in the microenvironment. We employed the non-interferometric wide-field optical profilometry (NIWOP) technique to quantify the membrane roughness of living neuroblastoma cells under various treatments that could change the mechanical properties of the cells.ResultsThe membrane roughness was reduced as the neuroblastoma cell was treated with paclitaxel, which increases cellular stiffness by translocating microtubules toward the cell membranes. The treatment of positively charged gold nanoparticles (AuNPs) showed a similar effect. In contrast, the negatively charged AuNPs did not cause significant changes of the membrane roughness. We also checked the membrane roughness of fixed cells by using scanning electron microscopy (SEM) and confirmed that the membrane roughness could be regarded as a parameter reflecting cellular mechanical properties. Finally, we monitored the temporal variations of the membrane roughness under the treatment with a hypertonic solution (75 mM sucrose in the culture medium). The membrane roughness was increased within 1 h but returned to the original level after 2 h.ConclusionsThe results in the present study suggest that the optical measurement on membrane roughness can be regarded as a label-free method to monitor the changes in cell mechanical properties or binding properties of nanoparticles on cell surface. Because the cells were left untouched during the measurement, further tests about cell viability or drug efficacy can be done on the same specimen. Membrane roughness could thus provide a quick screening for new chemical or physical treatments on neuronal cells.

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Section: Discussionmentioning

confidence: 99%

Membrane roughness as a sensitive parameter reflecting the status of neuronal cells in response to chemical and nanoparticle treatments

et al. 2016

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“…They are mainly used in soft tissue surgery for cutting and cauterization [ 1 , 2 ]. They are also used in biostimulation and photodynamic therapy [ 3 , 4 , 5 ]. Their usefulness stems from their small size, low cost of operation and the use of flexible optical fibres, which have a positive impact on work comfort.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Effects of Laser Light Combining Three Wavelengths (450, 520 and 640 nm) on Temperature Increase and Depth of Tissue Lesions in an Ex Vivo Study

et al. 2020

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Background: Lasers are widely used in medicine in soft and hard tissue surgeries and biostimulation. Studies found in literature typically compare the effects of single-wavelength lasers on tissues or cell cultures. In our study, we used a diode laser capable of emitting three components of visible light (640 nm, red; 520 nm, green; 450 nm, blue) and combining them in a single beam. The aim of the study was to assess the effects of laser radiation in the visible spectrum on tissue in vitro, depending on the wavelength and pulse width. Methods: All irradiations were performed using the same output power (1.5 W). We used various duty cycles: 10, 50, 80 and 100% with 100 Hz frequency. Maximum superficial temperature, rate of temperature increase and lesion depth were investigated. Results: Maximum superficial temperature was observed for 450 + 520 nm irradiation (100% duty cycle). The highest rate of increase of temperature was noted for 450 + 520 nm (100% duty cycle). Maximum lesion depth was observed in case of three-wavelength irradiation (450 + 520 + 640 nm) for 100, 80 and 50% duty cycles. Conclusions: The synergistic effect of two-wavelength (450 + 520 nm) irradiation was observed in case of maximum temperature measurement. The deepest depth of lesion was noted after three-wavelength irradiation (450 + 520 + 640 nm).

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“…Optical microscopy techniques allow quantifying the lateral cell shape in terms of spreading area, circularity, roundness, eccentricity, or more complex geometrical parameters. [4][5][6][7] Scanning probe techniques such as atomic force microscopy (AFM) or scanning ion conductance microscopy (SICM) obtain high-resolution topography images of the cell surface, thereby additionally allowing to quantify cell height, volume, surface area, 8) flatness, [9][10][11] roughness, [12][13][14][15][16][17][18] or dynamics of the cell surface. [19][20][21][22] In this study, we assessed the vertical (three-dimensional) shape of individual adherent cells and of cells in confluent layers by evaluating the distribution of height values in topography images obtained by SICM.…”

Section: Introductionmentioning

confidence: 99%

Skewness of the height distribution in cell topography images is a measure of cell shape

Seifert¹,

Rheinlaender²,

Schäffer³

2018

Jpn. J. Appl. Phys.

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The regulation of cell shape is crucial for the functioning of living cells. To analyze cell function, it is therefore important to quantify cell shape. We present an approach for the quantification of vertical cell shape that is based on a statistical analysis of height distributions in topography images such as obtained by scanning probe microscopy. Using scanning ion conductance microscopy (SICM), we found that induced cytoskeletal alterations led to a change from a dome-like toward a fried-egg-like vertical cell shape. This shape change affected a cell’s height distribution and the symmetry of this distribution. We used the third central moment of the distribution, the skewness, as a statistical measure of the distribution’s symmetry and therefore of vertical cell shape. This approach provides an unbiased and fast method for the analysis of vertical cell shape and works even for confluent cell layers.

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AFM-based bivariate morphological discrimination of apoptosis induced by photodynamic therapy using photosensitizer-functionalized gold nanoparticles

Abstract: Typical examples of the morphology of one viable and one apoptotic cell together with the statistical analysis of a larger cell ensemble subsequent to photodynamic treatment.

Cited by 4 publications

References 36 publications

Membrane roughness as a sensitive parameter reflecting the status of neuronal cells in response to chemical and nanoparticle treatments

Membrane roughness as a sensitive parameter reflecting the status of neuronal cells in response to chemical and nanoparticle treatments

Assessment of Effects of Laser Light Combining Three Wavelengths (450, 520 and 640 nm) on Temperature Increase and Depth of Tissue Lesions in an Ex Vivo Study

Skewness of the height distribution in cell topography images is a measure of cell shape

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