Biomedical subjects

Maciej Mazur

Publications and source records attributed to Maciej Mazur.

7 recordsLinked to original sources

PubMed2006

Probing organization and communication at layered interfaces.

We have investigated the local organization intrinsic to a variety of interfacial structures, by both electrochemical and spectroscopic means. Our focus has been on the design and construction of biomimetic interfaces, where a lipid bilayer or a hybrid bilayer membrane can be bound to an interface. The goal of this work is ultimately to create an interface on a transducer surface that can support an enzyme in its active form. To this point, we have examined the extent of organization that is achievable in monolayers that will be used to bind bilayer structures to a transducer surface. Our electrochemical data point to the important role of the substrate surface in determining adlayer organization. We have also investigated the fluidity and structural heterogeneity of lipid bilayers using time-resolved and steady state fluorescence spectroscopy. Our data point to the highly interactive nature of lipid bilayer constituents, where perturbations introduced to one region have significant consequences on other regions of the bilayer. Such information is directly relevant to the existence and properties of lipid raft structures in both model and biological bilayers.

Biomimetic Materials↗

PubMed2005

Use of zirconium-phosphate-carbonate chemistry to immobilize polycyclic aromatic hydrocarbons on boron-doped diamond.

We report on the formation of monomolecular layers of perylene- and pyrene-alkanoic acids on boron-doped diamond (BDD) substrates. The carboxylic acid layers are bound by coordination to zirconium phosphate (ZP) functionalities on the BDD substrate surface. The resulting Zr-phosphate-carbonate (ZPC) linkages between the substrate and the adlayer are asymmetric, of the form -(OPO3(2-) Zr4+-O2C-R)+ X-. Pyrene and perylene are well-established optical probes of polarity and viscosity at interfaces. We have used electrochemical and steady-state fluorescence techniques to study the loading density and behavior of these monomolecular films, allowing comparison of BDD and indium-doped tin oxide (ITO) substrates. Electrochemical data suggest that the pyrene chromophores are positioned roughly at the same distance from the surface, regardless of the length of the anchoring alkanoic acid chain, a finding that can be explained by the pyrene lying on the substrate surface. Such a conformation is plausible given the surface coverage (5 x 10(-11) mol/cm2, ca. 0.1 monolayer) we measure for these systems.

Boron↗

PubMed2005

Probing intermolecular communication with surface-attached pyrene.

We report on the covalent attachment of pyrene derivatives to solid substrates and their spectroscopic and electrochemical characterization. We have constructed several molecular assemblies attached to silica and indium-doped tin oxide surfaces where pyrene molecules are co-immobilized with other functionalities. It was shown that the addition of hydrophobic molecules to the pyrene-containing interface results in a significant decrease in the pyrene I1/I3 vibronic emission band ratio and an increase in the water drop contact angle due to increased hydrophobicity of the interface. The co-attachment of perylenedodecanoic acid, for which the absorption band overlaps with the emission spectrum of pyrene, shows significant intermolecular communication between these species. The co-immobilization of ferrocene serves as an effective fluorescence quencher for tethered pyrene. In all cases, our data point to significant intermolecular communication between adsorbate species, and the combination of spectroscopic and electrochemical interrogation provides insight into the loading density and local environment(s) characteristic of these interfaces.

Journal Article↗

PubMed2005

Oxidative transformations of surface-bound perylene.

We report on the covalent attachment of perylene derivatives to silica and indium-doped tin oxide surfaces. The spectroscopic properties of the immobilized fluorophores are studied by steady-state and time-resolved emission spectroscopy. The redox properties of the molecules are examined by electrochemical methods. It was found that the oxidation of perylene in aqueous medium results in the formation of perylenequinones. The transformation proceeds through a number of steps, with monohydroxyperylene(s) being the intermediate species. The final oxidation products are three isomeric forms of the perylenequinone/perylenehydroquinone redox couple. Understanding the mechanism of perylene transformation allows estimation of the concentration of molecules on the surface, and comparison of these results to those for pyrene and anthracene derivatives underscores the generality of this type of oxidative degradation for polycyclic aromatic hydrocarbons.

Journal Article↗

PubMed2005

Surface immobilized optical probes: pyrene molecules covalently attached to silica and indium-doped tin oxide.

We report on the covalent attachment of pyrene to quartz and indium-doped tin oxide (ITO) surfaces, and its characterization by steady-state and time-resolved emission spectroscopy. We estimate the chromophore surface coverage on the basis of their electrochemical oxidation mechanism in acidic solution. Electrochemical oxidation of immobilized pyrene results in the formation of radical cations, which are converted into hydroxypyrene and, after a second oxidation step, are transformed into isomeric forms of dihydroxypyrene/pyrenedione redox couples. Our findings demonstrate that surface-bound pyrene can be used as a spectral probe in environments that are isolated from oxidizing conditions and agents.

Indium↗

PubMed2004

Electroless deposition of poly(2-alkoxyaniline)s.

The in situ deposition of poly(2-alkoxyaniline)s onto oxide surfaces is reported. It is demonstrated that the identity of the substrate can have a pronounced effect on the polymerization rate of these substituted polyanilines. Poly(2-alkoxyaniline)s deposit efficiently onto indium-doped tin oxide (ITO), but deposition onto quartz proceeds slowly. The critical stage in the deposition process is shown to be polymerization of the adsorbed oligomeric species. When this polymerization process is catalyzed by the surface, polymer growth is enhanced, and we find that conducting substrates mediate this apparent catalytic process. We demonstrate selective deposition by growing poly(2-alkoxyaniline) adlayers onto patterned ITO/quartz substrates.

Journal Article↗

PubMed2003

[Inverted papilloma of the nose and paranasal sinuses: diagnosis and treatment].

The authors present a retrospective study of 6 patients with inverted papilloma, which appeared in the material of ENT Clinic in Wrocław in years 1996-2001. In the group of treated patients, we can recognize 5 men and one woman at the age between 42 to 82. Average age amounted to 62 years. At all the patients the papilloma inversum was diagnosed completely accidentally, during histopathological examination, after having polypectomy or Calwell-Luca operation. Operating treatment was proceeded by performing the CT or NMR test. In four cases the Denker's operation was done, in one case More's and in another one we performed the endoscopy operation (limited changes to ethmoidal labyrinth). The patients stay under the observation for 8 months to even 5 years. In one case we observed a relapse, which occurred after 8 months (patient after the Moure's operation). In all the rest cases a relapse was not identify.

Adult↗