Zakład Fizyki Makromolekularnej
Strona główna


od 2020-09-20

Dr Zuzanna Pietralik-Molińska  | 2008-10 - obecnie


   WF UAM pokój: 136      +48 61-829-5266

  0000-0003-2990-7047     35771382900  

Zainteresowania naukowe:
Procesy agregacji białek amyloidogennych. Charakterystyka oligomerów ludzkiej cystatyny C oraz ich znaczenie w rozwoju chorób neurodegeneracyjnych. Systemy dostarczania leków oraz terapeutycznych kwasów nukleinowych, badania układów transportujących na bazie fosfolipidów i surfaktantów polimerycznych oraz ich kompleksów z DNA i siRNA. Zastosowanie promieniowania synchrotronowego oraz techniki małokątowego rozpraszania promieniowania rentgenowskiego do badań układów biologicznych.

Publikacje           Doktorzy      Magistrowie      Licencjusze      Seminaria


Szutkowski K., Kołodziejska Ż., Pietralik Z., Zhukov I., Skrzypczak A., Materna K., Kozak M.

Clear distinction between CAC and CMC revealed by high-resolution NMR diffusometry for a series of bis-imidazolium gemini surfactants in aqueous solutions The aggregation behavior in the transition region was studied for a series of dicationic surfactants 3,3'-[alpha,omega-(dioxaalkane)]bis(1-dodecylimidazolium)dichlorides with varied spacer length from two to twelve carbon atoms. We employed Nuclear Magnetic Resonance diffusometry and Bayesian DOSY analysis to obtain the aggregate size distribution in the transition region. The critical concentrations CC were independently obtained from surface tension, electric conductivity, UV-Vis and NMR methods. The micelle aggregation numbers were estimated from the self-diffusion coefficients and were independently confirmed using steady-state fluorescence quenching. The morphology of the aggregates was characterized by small-angle scattering of synchrotron radiation and molecular dynamics simulations. The obtained CC values are identified as critical aggregation concentrations CAC. A broad transition region was observed, and stable micelles were obtained at much higher concentrations than CAC. The accurate CMC values could not be identified for the systems in the study. We indicated that the distribution of aggregate size becomes small and the system becomes homogeneous at much larger concentrations than CAC (typically 15-20 mM). The existence of a slow exchange between two environments, an aggregate and aqueous environment, was confirmed by H-1 NMR and 2D HSQC NMR spectroscopy.

RSC Advances, 8(67), 38470-38482 (2018)

DOI: 10.1039/c8ra07081d   (Pobrane:  2019-03-21)


Neunert G., Tomaszewska-Gras J., Siejak P., Pietralik Z., Kozak M., Polewski K.

Disruptive effect of tocopherol oxalate on DPPC liposome structure: DSC, SAXS, and fluorescence anisotropy studies alpha-Tocopherol oxalate (TO), a tocopherol ester derivative, was investigated for its effect on the structural changes of fully hydrated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, as a function of concentration and temperature, by applying differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and DPH fluorescence anisotropy methods. The DSC and DPH anisotropy data indicated that TO embedded into DPPC membrane lowered the enthalpy (Delta H-m) and temperature (T-m) of the main phase transition as well its cooperativity. Fluidization of the membrane at a lowered temperature was accompanied by formation of mixed structures of tocopherol-enriched domains. SAXS studies showed the formation of various ordered structures in DPPC gel-phase during incorporation of TO into the bilayer, as evidenced by the existence of lamellar phases with repeat distances (d) of 6.13 and 6.87 nm, assigned to TO-enriched domains and a lamellar, liquid-ordered DPPC phase with d = 8.45 nm at increasing TO concentrations with lowering and broadening of the Bragg peaks, and diffuse scattering, characteristic of a fluid L-alpha phase, were observed. In DPPC fluid-phase, the increasing presence of TO at low concentrations resulted in the appearance of a liquid-ordered phase with repeat d = 6.9 nm coexistent with a lamellar structure with d = 9.2 nm, assigned to liquid-disordered structures. An increasing repeat distance observed with raising the TO amount in the DPPC bilayer evolved from an increasing interlamellar water layer of increasing thickness. Presence of TO facilitated penetration of water molecules into the acyl chain region which decreased van der Waals interactions in the bilayer. The DSC, SAXS, and fluorescence anisotropy data established that TO exhibited pronounced disruptive activity in DPPC membranes compared to a-tocopherol. The driving force of the observed action was attributed to electrostatic and dipole interactions of the acidic moiety with the polar head group of phospholipids in the interface region of the bilayer.

Chemistry and Physics of Lipids, 216, 104-113 (2018)

DOI: 10.1016/j.chemphyslip.2018.10.001   (Pobrane:  2019-03-21)


Chrabąszczewska M., Maszota-Zieleniak M., Pietralik Z., Taube M., Rodziewicz-Motowidło S., Szymańska A., Szutkowski K., Clemens D., Grubb A., Kozak M.

Cyclic trimer of human cystatin C, an amyloidogenic protein - molecular dynamics and experimental studies Human cystatin C (HCC) is a cysteine protease inhibitor that takes a series of oligomeric forms in solution (e.g., dimers, trimers, tetramers, decamers, dodecamers, and other higher oligomers). The best-known form of cystatin C is the dimer, which arises as a result of a domain swapping mechanism. The formation of the HCC oligomeric forms, which is most likely due to this domain swapping mechanism, is associated with the aggregation of HCC into amyloid fibrils and deposits. To investigate the structure of a specific HCC oligomer, we developed a covalently stabilized trimer of HCC. An atomic model of this HCC trimer was proposed on the basis of molecular docking and molecular dynamics simulations. The most stable model of the HCC trimer obtained from the molecular dynamics simulations is characterized by a well-preserved secondary structure. The molecular size and structural parameters of the HCC trimer in solution were also confirmed by Small Angle Neutron Scattering and Nuclear Magnetic Resonance Diffusometry. Published by AIP Publishing.

Journal of Applied Physics, 123(17), Article Number: 174701 (2018)

DOI: 10.1063/1.5023807   (Pobrane:  2019-03-21)


Ivashchenko O., Peplińska B., Gapiński J., Flak D., Jarek M., Załęski K., Nowaczyk G., Pietralik Z., Jurga S.

Silver and ultrasmall iron oxides nanoparticles in hydrocolloids: effect of magnetic field and temperature on self-organization Micro/nanostructures, which are assembled from various nanosized building blocks are of great scientific interests due to their combined features in the micro- and nanometer scale. This study for the first time demonstrates that ultrasmall superparamagnetic iron oxide nanoparticles can change the microstructure of their hydrocolloids under the action of external magnetic field. We aimed also at the establishment of the physiological temperature (39°C) influence on the self-organization of silver and ultrasmall iron oxides nanoparticles (NPs) in hydrocolloids. Consequences of such induced changes were further investigated in terms of their potential effect on the biological activity in vitro. Physicochemical characterization included X-ray diffraction (XRD), optical microscopies (SEM, cryo-SEM, TEM, fluorescence), dynamic light scattering (DLS) techniques, energy dispersive (EDS), Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopies, zeta-potential and magnetic measurements. The results showed that magnetic field affected the hydrocolloids microstructure uniformity, fluorescence properties and photodynamic activity. Likewise, increased temperature caused changes in NPs hydrodynamic size distribution and in hydrocolloids microstructure. Magnetic field significantly improved photodynamic activity that was attributed to enhanced generation of reactive oxygen species due to reorganization of the microstructure.

Scientific Reports, 8, 4041 (2018)

DOI: 10.1038/s41598-018-22426-2   (Pobrane:  2018-03-20)


Scheibe B., Mrówczyński R., Michalak N., Zaleski K., Matczak M., Kempiński M., Pietralik Z., Lewandowski M., Jurga S., Stobiecki F.

Anchoring Fe3O4 nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating Reduced graphene oxide-magnetite hybrid aerogels attract great interest thanks to their potential applications, e.g., as magnetic actuators. However, the tendency of magnetite particles to migrate within the matrix and, ultimately, escape from the aerogel structure, remains a technological challenge. In this article we show that coating magnetite particles with polydopamine anchors them on graphene oxide defects, immobilizing the particles in the matrix and, at the same time, improving the aerogel structure. Polydopamine coating does not affect the magnetic properties of magnetite particles, making the fabricated materials promising for industrial applications.

Beilstein Journal of Nanotechnology, 9, 591-601 (2018)

DOI: 10.3762/bjnano.9.55   (Pobrane:  2018-03-20)


Viter R., Savchuk, M., Iatsunskyi I., Pietralik Z., Starodub N., Shpyrka, N., Ramanaviciene A., Ramanavicius A.

Analytical, thermodynamical and kinetic characteristics of photoluminescence immunosensor for the determination of Ochratoxin A Ochratoxin A (OTA) is one of the most widespread and dangerous food contaminants. Therefore, rapid, label free and precise detection of low OTA concentrations requires novel gensing elements with advanced bioanalytical properties. In the present paper we report photoluminescence (PL) based immunosensor for the detection of OTA. During the development of immunosensor photoluminescent ZnO nanorods (ZnO-NRs) were deposited on glass substrate. Then the ZnO-NRs were silanized and covalently modified by Protein-A (Glass/ ZnO-NRs/Protein-A). The latest structure was modified by antibodies against OTA (Anti-OTA) in order to form OTA-selective layer (Glass/ZnO-NRs/Protein-A/Anti-OTA). In order to improve immunosensors selectivity the surface of Glass/ZnO-NRs/Protein-A/Anti-OTA was additionally blocked by BSA. Formed Glass/ZnO-NRs/ Protein-A/BSA &Anti-OTA structures were integrated within portable fiber optic detection system, what is important for the development of low cost and portable immunosensors. The immunosensor has been tested in a wide range of OTA concentrations from 10(-4) ng/ml until 20 ng/ml. Interaction isotherms were derived from atialytical signals of immunosensor. Association constant and Gibbs free energy for the interaction of Glass/ ZnO-NRs/Protein-A/Anti-OTA with OTA were calculated, analyzed and compared with some other related results. Sensitivity range and limit of detection were determined as 0.1-1 ng/ml and 10(-2) ng/ml, respectively. Interaction kinetics of ZnO-NRs with OTA was evaluated. Response time of the immunosensor toward OTA was in the range of 500-800 s. Some insights related to the mechanism of PL-signal generation are proposed and discussed.

Biosensors & Bioelectronics, 99, 237-243 (2018)

DOI: 10.1016/j.bios.2017.07.056   (Pobrane:  2017-11-06)


Piosik A., Żurowski K., Pietralik Z., Hędzelek W., Kozak M.

Structural studies of degradation process of zirconium dioxide tetragonal phase induced by grinding with dental bur Zirconium dioxide has been widely used in dental prosthetics. However, the improper mechanical treatment can induce changes in the microstructure of zirconium dioxide. From the viewpoint of mechanical properties and performance, the phase transitions of ZrO2 from the tetragonal to the monoclinic phase induced by mechanical processing, are particularly undesirable. In this study, the phase transitions of yttrium stabilized zirconium dioxide (Y-TZP) induced by mechanical treatment are investigated by the scanning electron microscopy (SEM), atomic force microscopy (AFM) and powder diffraction (XRD). Mechanical stress was induced by different types of drills used presently in dentistry. At the same time the surface temperature was monitored during milling using a thermal imaging camera. Diffraction analysis allowed determination of the effect of temperature and mechanical processing on the scale of induced changes. The observed phase transition to the monoclinic phase was correlated with the methods of mechanical processing.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 411, 85-93 (2017)

DOI: 10.1016/j.nimb.2017.07.024   (Pobrane:  2017-12-08)


Andrzejewska W., Pietralik Z., Skupin M., Kozak M.

Structural studies of the formation of lipoplexes between siRNA and selected bis-imidazolium gemini surfactants Dicationic (gemini) surfactants are agents that can be used for the preparation of stable complexes of nucleic acids, particularly siRNA for therapeutic purposes. In this study, we demonstrated that bis-imidazolium gemini surfactants with variable lengths of dioxyalkyl linker groups (from dioxyethyl to dioxydodecyl) and dodecyl side chains are excellent for the complexation of siRNA. All of these compounds effectively complexed siRNA in a charge ratio range (p/n) of 1.5-10. The low resolution structure of siRNA oligomers was characterised by small angle scattering of synchrotron radiation (SR-SAXS) and ab initio modelling. The structures of the formed complexes were also analysed using SR-SAXS, circular dichroism studies and electrophoretic mobility tests. The most promising agents for complexation with siRNA were the surfactants that contained dioxyethyl and dioxyhexyl spacer groups.

Colloids and Surfaces B: Biointerfaces, 146, 598-606 (2016)

DOI: 10.1016/j.colsurfb.2016.06.062   (Pobrane:  2016-10-11)


Jastrzębska K., Felcyn E., Kozak M., Szybowicz M., Buchwald T., Pietralik Z., Jesionowski T., Mackiewicz A., Dams-Kozłowska H.

The method of purifying bioengineered spider silk determines the silk sphere properties Bioengineered spider silks are a biomaterial with great potential for applications in biomedicine. They are biocompatible,biodegradable and can self-assemble into films, hydrogels, scaffolds, fibers, capsules and spheres. A novel, tag-free, bioengineered spider silk named MS2(9x) was constructed. It is a 9-mer of the consensus motif derived from MaSp2- the spidroin of Nephila clavipes dragline silk. Thermal and acidic extraction methods were used to purify MS2(9x). Both purification protocols gave a similar quantity and quality of soluble silk; however, they differed in the secondary structure and zeta potential value. Spheres made of these purified variants differed with regard to critical features such as particle size, morphology, zeta potential and drug loading. Independent of the purification method, neither variant of the MS2(9x) spheres was cytotoxic, which confirmed that both methods can be used for biomedical applications. However, this study highlights the impact that the applied purification method has on the further biomaterial properties.

Scientific Reports, 6, 28106, 1-15 (2016)

DOI: 10.1038/srep28106


Pietralik Z., Skrzypczak A., Kozak M.

Dicationic surfactants with glycine counter ions for oligonucleotide transportation Gemini surfactants are good candidates to bind, protect, and deliver nucleic acids. Herein, the concept of amino acids (namely glycine) as counter ions of gemini surfactants for gene therapy application was explored. This study was conducted on DNA and RNA oligomers and two quaternary bis-imidazolium salts, having 2,5-dioxahexane and 2,8-dioxanonane spacer groups. The toxicity level of surfactants was assessed by an MTT assay, and their ability to bind nucleic acids was tested through electrophoresis. The nucleic acid conformation was established based on circular dichroism and infrared spectroscopic analyses. The structures of the formed complexes were characterized by small-angle scattering of synchrotron radiation. Both studied surfactants appear to be suitable for gene therapy; however, although they vary by only three methylene groups in the spacer, they differ in binding ability and toxicity. The tested oligonucleotides maintained their native conformations upon surfactant addition and the studied lipoplexes formed a variety of structures. In systems based on a 2,5-dioxahexane spacer, a hexagonal phase was observed for DNA-surfactant complexes and a micellar phase was dominant with RNA. For the surfactant with a 2,8-dioxanonane spacer group, the primitive cubic phase prevailed.

ChemPhysChem, 17, 2424-2433 (2016)

DOI: 10.1002/cphc.201600175


Pietralik Z., Murawska M., Szymańska A., Kumita J.R., Dobson C.M., Kozak M.

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Structural studies of the oligomerization process of human cystatin C variants Human cystatin C (HCC), an inhibitor of cysteine proteases, is also involved in amyloidogenic processes within the human body. In the crystal structure, as in solution, wild-type (WT) cystatin C dimerizes via a domain swapping mechanism. The same process has also been shown to be important for protein oligomerization. Aggregation of HCC results in a heterogeneous mixture of species, both oligomeric and fibrillar, with varying shapes, sizes and molecular weights.
The goal of our study was to characterize the assembly process of potentially neurotoxic oligomers of WT and variant HCC in solution. The oligomerization processes of several point mutation variants of HCC (V57N, V57P, V57D, V57G and L68V), with specific dimerization properties [3], were compared to the WT protein. Prepared oligomers were purified by size-exclusion chromatography and using TEM and AFM studies, we observed characteristic donutlike structures along with fibrils and we determined the size distribution of cystatin C oligomers obtained from the WT and variant forms. Independently, the oligomerization process was analyzed by fluorescence spectroscopy and visualized by native electrophoresis. Additionally, induced secondary structure changes were characterised by circular dichroism (CD) and infrared (FTIR) spectroscopies. Finally, the structural studies were supplemented with the modelling of the larger HCC oligomers using molecular dynamics simulations, allowing the identification of the most stable oligomeric forms of HCC to be determined.

Biophysical Journal, 110(3) S1, 26A (2016)

DOI: 10.1016/j.bpj.2015.11.205   (Pobrane:  2017-12-08)


Ivashchenko O., Jurga-Stopa J., Coy E., Peplińska B., Pietralik Z., Jurga S.

Fourier transform infrared and Raman spectroscopy studies on magnetite/Ag/antibiotic nanocomposites This article presents a study on the detection of antibiotics in magnetite/Ag/antibiotic nanocomposites using Fourier transform infrared (FTIR) and Raman spectroscopy. Antibiotics with different spectra of antimicrobial activities, including rifampicin, doxycycline, cefotaxime, and ceftriaxone, were studied. Mechanical mixtures of antibiotics and magnetite/Ag nanocomposites, as well as antibiotics and magnetite nanopowder, were investigated in order to identify the origin of FTIR bands. FTIR spectroscopy was found to be an appropriate technique for this task. The spectra of the magnetite/Ag/antibiotic nanocomposites exhibited very weak (for doxycycline, cefotaxime, and ceftriaxone) or even no (for rifampicin) antibiotic bands. This FTIR “invisibility” of antibiotics is ascribed to their adsorbed state. FTIR and Raman measurements show altered C—O, C=O, and C—S bonds, indicating adsorption of the antibiotic molecules on the magnetite/Ag nanocomposite structure. In addition, a potential mechanism through which antibiotic molecules interact with magnetite/Ag nanoparticle surfaces is proposed.
© 2015 Elsevier B.V. All rights reserved.

Applied Surface Science, 364, 400-409 (2016)

DOI: 10.1016/j.apsusc.2015.12.149   (Pobrane:  2017-12-08)


Zalewski P., Skibiński R., Szymanowska-Powałowska D., Piotrowska H., Kozak M., Pietralik Z., Bednarski W., Cielecka-Piontek J.

The radiolytic studies of cefpirome sulfate in the solid state The possibility of applying radiation sterilization to cefpirome sulfate was investigated. The lack of changes in the chemical structure of cefpirome sulfate irradiated with a dose of 25 kGy, required to attain sterility, was confirmed by UV, FT-IR, Raman, DSC and chromatographic methods. Some radical defects with concentration no more than over a several dozen ppm were created by radiation. The antibacterial activity of cefpirome sulfate for two Gram-positive and three Gram-negative strains was changed. The radiation sterilised cefpirome sulfate was not in vitro cytotoxic against fibroblast cells.

Journal of Pharmaceutical and Biomedical Analysis, 118, 410-416 (2016)

DOI: 10.1016/j.jpba.2015.11.008


Pietralik Z.. Kołodziejska Ż., Weiss M., Kozak M.

Gemini surfactants based on bis-imidazolium alkoxy derivatives as effective agents for delivery of nucleic acids: A structural and spectroscopic study The success rate of gene therapy depends on the efficient transfection of genetic material into cells. The golden mean between harmlessness and high effectiveness can be provided by synthetic lipid-like molecules that are similar to the components of biological membranes. Cationic gemini surfactants are one such moiety and because of their favourable physicochemical properties (double positive electric charge, reduced toxicity, low values of critical micelle concentration), they show great potential as delivery system components for genetic material in gene therapy. The aim of this study was to investigate the process of the complexation of cationic gemini surfactants with nucleic acids: double-stranded DNA of different sizes (21 bp, ~185 bp, ~20 kbp) and siRNA (21 bp). The tested series of dicationic surfactants consists of bis-imidazolium quaternary salts with varying lengths of hydrophobic side chains (m = 5, 6, 7, 8, 9, 11, 12, 14, 16). On the basis of the data obtained by circular dichroism spectroscopy and electrophoresis, we concluded that the studied gemini surfactants with long side chains effectively bind nucleic acids at low concentrations, which leads to the formation of stable lipoplexes. Images obtained by atomic force microscopy also confirmed the formation of vesicular structures, i.e., complexes between DNA and surfactants. The cytotoxicity of selected surfactants was also tested on HeLa cells. The surfactant toxicity significantly depends on surfactant geometry (the length of hydrophobic chain).

PloS ONE, 10(12), 1-22 (2015)

DOI: 10.1371/journal.pone.0144373


Balcerzak M., Pietralik Z., Domka L., Skrzypczak A., Kozak M.

Adsorption of dimeric surfactants in lamellar silicates The adsorption of different types of cationic surfactants in lamellar silicates changes their surface character from hydrophilic to hydrophobic. This study was undertaken to obtain lamellar silicates modified by a series of novel dimeric (gemini) surfactants of different length alkyl chains and to characterise these organophilised materials. Synthetic sodium montmorillonite SOMASIF® ME 100 (M) and enriched bentonite of natural origin (Nanoclay - hydrophilic bentonite®) were organophilised with dimeric (gemini) surfactants (1,1′-(1,4-butanediyl) bis(alkoxymethyl)imidazolium dichlorides). As a result of surfactant molecule adsorption in interlamellar space, the d-spacing (d001) increased from 0.97 nm (for the anhydrous structure) to 2.04 nm. A Fourier transform infrared spectroscopy (FTIR) analysis of the modified systems reveals bands assigned to the stretching vibrations of the CH2 and CH3 groups and the scissoring vibrations of the NH group from the structure of the dimeric surfactants. Thermogravimetric (TG) and derivative thermogravimetric (DTG) studies imply a four-stage process of surfactant decomposition. Scanning electron microscopy (SEM) images provide information on the influence of dimeric surfactant intercalation into the silicate structures. Particles of the modified systems show a tendency toward the formation of irregularly shaped agglomerates.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 364, 108-115 (2015)

DOI: 10.1016/j.nimb.2015.07.135   (Pobrane:  2017-12-08)


Pietralik Z., Kumita J.R., Dobson C.M., Kozak M.

The influence of novel gemini surfactants containing cycloalkyl side-chains on the structural phases of DNA in solution Very important to gene therapy is the delivery system of the nucleic acids (called a vector), which will enhance the efficiency of the transport of new DNA into cells whilst protecting against damage. A promising alternative to the currently used viral vectors are the systems based on amphiphilic compounds - lipoplexes. Among them, gemini surfactants, which consist of two hydrophobic chains and two cationic heads connected by a linker spacer group, appear to be promising candidates. The subject of this study involves two gemini surfactants, alkoxy derivatives of bis-imidazolium quaternary salts, differing in the length of their spacer groups and how they interact with two types of salmon sperm DNA (low and high molecular weight (MW)) or plasmid DNA (pDNA). The mixtures of gemini surfactants with nucleic acids of differing p/n ratios (positive-to-negative charge ratio) were characterised by small angle X-ray scattering (SAXS) of synchrotron radiation, dynamic light scattering (DLS), circular dichroism (CD) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and gel electrophoresis techniques. This analysis allows for the selection of the most suitable and promising candidates for non-viral vectors in gene therapy, determination of the conditions needed to form stable complexes, identification of conformational changes in the DNA molecules upon interactions with gemini surfactants and in some cases, determination of the structures formed in these lipoplexes.
(C) 2015 Elsevier B.V. All rights reserved.

Colloids and Surfaces B: Biointerfaces, 131, 83-92 (2015)

DOI: 10.1016/j.colsurfb.2015.04.042   (Pobrane:  2015-07-24)


Wolak J., Skupin M., Pietralik Z., Andrzejewska W., Kozak M.

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Studies of zwitterionic lipoplexes - nanosystem based on phospholipids and surfactants as innovative delivery systems for gene therapy The gene therapy is the one of the most promising method of treatment in contemporary medicine. This way of therapy is very useful in the treatment a dozen of incurable or fatal diseases. This method of treatment is leaned on implement a gene into patient's cells with the use of dedicated delivery systems (vectors). The main problem of gene therapy is to find the best vector which will be effective and will be not toxic for human cells. A good approach seems to be use of non-viral vectors like delivery system based on lipid-surfactant mixtures.

The aim of this study was to examine the possible application of selected amphoteric surfactants (zwitterionic alkyl derivatives of sulfobetaine) as complexing agents (with and without helper lipid) for nucleic acids (siRNA, low and high-molecular weight DNA).

The studies of DNA conformation in selected DNA - zwitterionic surfactant lipoplexes were performed using the circular dichroism (CD) spectroscopy. CD spectra were recorded in the spectral range 350 - 200 nm by using J-815 spectrometer (Jasco). The results obtained indicate that the DNA maintains the B-form for wide range of surfactant concentrations in the solution. The structure and organization of lipoplexes was also independently analyzed by the Fourier transform infrared spectroscopy. The absorption spectra for lipoplexes were collected by using FTIR spectrometer BRUKER Tensor 27 in the temperature range 2-40°C. The phase transitions in examined systems were studied by using the differential scanning calorimetry (DSC). Ability of creating of stable complexes in DNA-surfactant systems studied was confirmed using electrophoresis on agarose gel. For all formed stable lipoplexes the complete reduction of electrophoretic mobility was observed. Finally the transfection efficiency of selected systems were also tested on HeLa cells.

Biophysical Journal, 108(2) S1, 545A (2015)

DOI: 10.1016/j.bpj.2014.11.2989   (Pobrane:  2020-11-05)


Kozak M., Pietralik Z., Szymańska A., Taube M.

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Spectroscopic and SAXS studies of human cystatin c mutants - early stages of amyloid formation process Human cystatin C (HCC) is a cysteine protease inhibitor. This protein in pathological conditions, forms dimers via a “domain swapping” mechanism. HCC is also associated with two types of amyloid deposition diseases - hereditary amyloid angiopathy (related to the Leu68Gln mutation) and wild-type cystatin C co-precipitation.

The aim of our studies was the characterisation of the self-assembling properties of native and mutated (at positions 57 or 68) forms of human cystatin C in solution. The structure, overall conformation and secondary structure changes in solution were studied by Fourier transformed infrared spectroscopy (FTIR), circular dichroism spectroscopy (CD), dynamic light scattering (DLS) and time resolved small angle scattering of synchrotron radiation (TR-SAXS).

SAXS data for native and mutated HCC were subjected to analysis by using SVD and MCR-ALS methods as well as the low resolution structure determination. Besides the monomeric forms of human cystatin C, also dimers and higher oligomers were formed even after short (50-ms) exposure on synchrotron radiation. In addition we observed for first time, formation of domain swapped dimers of human cystatin C induced by irradiation. The spectroscopic studies confirmed conformational changes.

Authors acknowledge also the partial support by HARMONIA3 grant (Project No. 2012/06/M/ST4/00036) from National Science Centre (Poland).

Biophysical Journal, 108(2) S1, 516A (2015)

DOI: 10.1016/j.bpj.2014.11.2827   (Pobrane:  2020-11-05)


Andrzejewska W., Pietralik Z., Taube M., Skrzypczak A., Kozak M.

Structural and spectroscopic studies on the formation of lipoplexes between DNA and cationic gemini surfactants The process of complex formation between cationic gemini surfactants, 3,3'-[α,ω-(dioxaalkane)]bis(1-dodecylimidazolium) dichloride, with deoxyribonucleic acid (DNA) was studied. The study was performed for ten surfactants having spacer groups of different lengths used in 6 concentrations (5 mM, 2 mM, 1 mM, 0.5 mM, 0.2 mM, 0.1 mM) and a 6.5 μM DNA solution. The complex formation was verified by circular dichroism spectroscopy and gel electrophoresis. The complexes were found to be stable and the process of complex formation was reproducible, efficient and immediate.

Polimery/Polymers, 59(7-8), 569-574 (2014)

DOI: 10.14314/polimery.2014.569
WWW:   (Pobrane:  2021-01-10)


Pietralik Z., Krzysztoń R., Kida W., Andrzejewska W. and Kozak M.

Structure and conformational dynamics of DMPC/dicationic surfactant and DMPC/dicationic surfactant/DNA systems Amphiphilic dicationic surfactants, known as gemini surfactants, are currently studied for gene delivery purposes. The gemini surfactant molecule is composed of two hydrophilic "head" groups attached to hydrophobic chains and connected via molecular linker between them. The influence of different concentrations of 1,5-bis (1-imidazolilo-3-decyloxymethyl) pentane chloride (gemini surfactant) on the thermotropic phase behaviour of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayers with and without the presence of DNA was investigated using Fourier transformed infrared (FTIR) and circular dichroism (CD) spectroscopies, small angle scattering of synchrotron radiation and differential scanning calorimetry. With increasing concentration of surfactant in DMPC/DNA systems, a disappearance of pretransition and a decrease in the main phase transition enthalpy and temperature were observed. The increasing intensity of diffraction peaks as a function of surfactant concentration also clearly shows the ability of the surfactant to promote the organisation of lipid bilayers in the multilayer lamellar phase.

International Journal of Molecular Sciences, 14(4), 7642-7659 (2013)

DOI: 10.3390/ijms14047642


Marciniec B., Dettlaff K., Naskrent M. Pietralik Z., Kozak M.

DSC and spectroscopic studies of disulfiram radiostability in the solid state The effect of ionising radiation on the physicochemical properties of disulfiram (Antabuse, Esperal, bis-diethylthiocarbamoil disulphide) has been studied by DSC, FTIR, EPR, MS, TLC and HPLC. Sterilisation was carried out in the solid state, at room temperature and normal air humidity using the electron beam of 9.96 Mev from accelerator. All the measurements were made simultaneously for the irradiated and nonirradiated substance. It has been found that the drug studied in solid phase when subjected to an electron beam corresponding to the irradiation in the doses 10-100 kGy shows the presence of free radicals (EPR), and a change in colour from white to pale green-grey that disappears after solution in water or methanol. After the irradiation with the dose of 100 kGy, its melting point and enthalpy slightly decreased. Also the content of the active substance decreases (HPLC -1.5%, UV -3.6%, iodometric titration method -2.7%) and trace amounts of the radiolysis products appear (HPLC). The substance irradiated with the doses 10-50 kGy does not show changes in the melting point, in the content and presence of the radiolysis products. The EPR results have shown that free radicals disappear after about a year and the discolouring disappears with them. The results of this study have shown that disulfiram can be subjected to sterilisation by irradiation with no deterioration of its physico-chemical properties, but a long time of storage needed to remove free radicals and discolouration questions the economic justification for this type of sterilisation.

Journal of Thermal Analysis and Calorimetry, 108(1), 33-40 (2012)

DOI: 10.1007/s10973-011-1810-4   (Pobrane:  2012-10-16)


Pietralik Z., Taube M., Balcerzak M., Skrzypczak A., Kozak M.

MAX-Lab Activity Report 2010, , 284-285 (2011)

WWW:   (Pobrane:  2011-09-22)


Pietralik Z., Taube M., Kozak A., Wieczorek D., Zielinski R., Kozak M.

MAX-Lab Activity Report 2010, , 286-288 (2011)

WWW:   (Pobrane:  2011-10-18)


Pietralik Z., Taube M., Skrzypczak A., Kozak M.

SAXS study of influence of gemini surfactant, 1,1'-(1,4-butanediyl)bis 3-cyclododecyloxymethylimidazolium di-chloride, on the fully hydrated DMPC The study has been performed on model systems of biological membranes obtained on the basis of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cationic gemini surfactant derivative of 1,1'-(1,4-butane)bis 3-alkyloxymethylimidazolium chlorides with cyclic chains. The small angle X-ray scattering SAXS results implied a gradual disappearance (as a function of surfactant concentration) of the lamellar phase typical of DMPC and formation of unilamellar phase - probably a bicellar phase.

Acta Physica Polonica A, 117(2), 311-314 (2010)

DOI: 10.12693/APhysPolA.117.311
WWW:   (Pobrane:  2021-01-10)

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