Sylwia Ptasinska

Sylwia Ptasinska

Maria Curie-Sklodowska University, Poland. M.Sc. (2001)
Leopold-Franzens-University, Austria. Ph.D. (2004)
Leopold-Franzens-University, Austria. Habilitation (2011)

view Dr. Ptasinska's webpage

Phone: (574) 631-2819
Email: sptasins@nd.edu
Office: 101 Radiation Research Building

Physical and Chemical Processes in Biosystems and on Semiconductor Surfaces


Scientific Interests

Interaction of organic molecules at solid interfaces

Ambient pressure and ultra high vacuum x-ray photoelectron spectroscopy of molecular interactions at metal and semiconductor surfaces.

Atmospheric pressure plasma jet induced chemistry

Development of plasma sources as a radiation tool for biological systems.

Dissociative electron attachment processes

Mass spectrometry of ion and neutral formation induced by electron attachment to molecules in the gas and condensed phases.

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Recent Accomplishments

Tailoring Bond Dissociation in Gas-Phase Biomolecules by Low-Energy Electrons

Gas-phase dissociative electron attachment (DEA) to N-methylformamide (NMF, HC(=O)NHCH3), measured with a locally designed and constructed, and recently optimized, high vacuum chamber, revealed site-selectivity in the DEA process leading to the formation of dehydrogenated, closed-shell anions. Based on results from theoretical modeling and experimental isotopic studies, we were able to determine the precise reaction pathways. The dominant fragmentations involved the formation of CN¯ and OCN¯, which are produced from electron capture by the π antibonding C=O orbital coupled with dissociation of the N-CH3 bond and formation of a C=N bond. Our studies contribute to the ongoing search for understanding and evaluation of biological effects involving low-energy electrons.

Morphology-dependent Oxidation on Semiconductor Surfaces

Interest in passivation of semiconductor nanostructures to improve fast optoelectronics and enhance solar cell efficiency is rapidly growing. We have focused recently on developing a fundamental understanding of the surface interaction between III-V semiconductors and common gaseous molecules such as oxygen, water vapor, and other small compounds. Interfacial chemistry is monitored in real time and under conditions close to ambient using near-ambient pressure X-ray photoelectron spectroscopy. Oxygen interaction with the GaAs surface was shown to be a dynamic oxidation processes, which involved the formation of gallium oxides (i.e., Ga2O and Ga2O3) with increased O2 pressure and/or temperature, as well as arsenic oxides. The latter mainly followed an increase of temperature. The level of total oxidation was demonstrated to strongly depend on the morphology of the GaAs sample, being distinctly higher in an ensemble of GaAs nanowires compared to a simple planar crystalline surface.

3D Mapping of Plasma Reactive Areas

Plasma Pic_49k

A nitrogen atmospheric pressure plasma jet (APPJ) is low-energy radiation, but it contains a plethora of reactive species. Many plasma species that are generated within plasma discharge diffuse across the open boundary of the visible jet into the surrounding air. As these species diffuse, their density decreases and extends the reactive area, which is difficult to quantify by the conventional plasma diagnostic techniques. We have found that oral cancer cells are very susceptible to plasma treatment; they can therefore be used as a marker of APPJ effective areas. Damaged cells were identified, visualized, and quantified using immunofluorescence assay. As a result, the effective area of damage and damage level were determined and plotted as 3D images. The obtained 3D maps showed a decrease in the number of damaged cells with a distance from direct contact of the APPJ with the cells and demonstrate a linear correlation between the increase of plasma effective area and treatment time.

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Selected Publications

 

Adhikari, E. and S. Ptasińska. “Correlation between plasma induced DNA damage level and helium atmospheric pressure plasma jet (APPJ) variables.” Eur. Phys. J. D 70 (2016): 180. link

Huang, W., J. Manser, P.V.  Kamat, and S. Ptasińska. “Evolution of chemical composition, morphology, and photovoltaic efficiency of CH3NH3Pbl3 perovskite under ambient conditions.” Chem. Mater. 28 (2016): 303. link

Milosavljevic, A.R., W. Huang, S. Sadhu, and S. Ptasińska. “Low-energy electron-induced degradation of organolead halide perovskite.” Angew. Chem. Int. Ed. 128 (2016): 10237. link

Zhang, X., and S. Ptasińska. “Electronic and chemical structure of the H2O/GaN(0001) interface under ambient conditions.” Sci. Rep. 6 (2016): 24848. link

Alizadeh, E., S. Ptasinska, and L.Sanche. "Transient anions on radiobiology and radiotherapy: from gaseous biomolecules to condensed organic and biomolecular solids>" In Radiation Effects in Materials; Monteiro, W.A., Ed., Chapter 8 (2016): 179. link

Arjunan, K.P., V. Sharma, S. Ptasinska. "Effects of Atmospheric Pressure Plasmas on Isolated and Cellular DNA- A Review." Int. J. Mol. Sci 16 (2015): 2971-3016. link

Zhang, X., S. Ptasinska. "Distinct and Dramatic Water Dissociation on GaP (111) tracked by Near Ambient Pressure XPS." Phys. Chem. Chem. Phys. 17 (2015): 3909-3918. link

Zhang, X., S. Ptasinska. "Evolution of Surface-Assisted Oxidation of GaAs (100) by Gas-Phase N2O, NO, and O2 under Near-Ambient Pressure Conditions." J. Phys. Chem. 119 (2015): 262-270. link

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