Ewa Rozniecka

Polish Academy of Sciences | PAN · Institute of Physical Chemistry

We developed a method of aligning silver nanowires in a microchannel and fixing them to glass substrates via appropriate functionalization. The attachment of nanowires to the substrate is robust with no variation of their angles over minutes. Specific conjugation with photoactive proteins is observed using wide-field fluorescence imaging in real-ti...

Yersiniosis is an infectious zoonotic disease caused by two enteropathogenic species of Gram-negative genus Yersinia: Yersinia enterocolitica and Yersinia pseudotuberculosis. Pigs and other wild and domestic animals are reservoirs for these bacteria. Infection is usually spread to humans by ingestion of contaminated food. Yersiniosis is considered...

Well-defined paths assembled of silver islands were fabricated by combining photolithography with wet-chemical synthesis. The islands feature lateral sizes of the order of 100 nm, and similar heights, thus promoting localized plasmon resonance. Wavelength-dependent fluorescence imaging as well as time-resolved fluorescence of photoactive proteins d...

Silver nanowires with varying diameters and submillimeter lengths were obtained by changing a reducing agent used during hydrothermal synthesis. The control over the nanowire diameter turns out to play a critical role in determining their plasmonic properties, including fluorescence enhancement and surface plasmon polariton propagation. Advanced fl...

We observe correlation between the length of surface plasmon polariton propagation in silver nanowires and the enhancement of fluorescence intensity due to coupling with localized plasmon resonances. The results of excitation wavelength-dependent fluorescence imaging of CdTe QDs uniformly deposited over silver nanowires indicate the strongest enhan...

We report on the synthesis of long silver nanowires using the hydrothermal method, with H2O2 as the reducing agent. Our approach yields nanowires with an average diameter and length of about 100 nm and 160 µm, respectively, reaching the maximum length of 800 µm. Scanning electron microscopy (SEM) measurements revealed the presence of a thick, inhom...

We demonstrate fast and simple route to selective virus detection using antibody-functionalized silver nanowires. While the immunocomplex formation takes place in solution, the presence of viruses is determined by correlating transmission and fluorescence images obtained after depositing nanowire solution on a substrate. Importantly, by mixing nano...

We apply wide-field fluorescence microscopy to measure real-time attachment of photosynthetic proteins to plasmonically active silver nanowires. The observation of this effect is enabled, on the one hand, by sensitive detection of fluorescence and, on the other hand, by plasmonic enhancement of protein fluorescence. We examined two sample configura...

An influence of titanium oxide (TiOx) deposition method, i.e., chemical (atomic layer deposition, ALD) and physical (reactive magnetron sputtering, RMS) vapor deposition, on the optical properties and surface chemical modification were investigated. TheTiOx film was used as a functional coating for enhancing sensing properties of two types of label...

Fast and reliable detection of viruses, including those specific to bacteria − bacteriophages − is crucial in clinical and veterinary practice, during biotechnological processes, and in basic research. In this paper, a highly sensitive long-period fiber grating (LPFG) label-free immunosensor is described for the detection of T7 bacteriophages. The...

We show that surface-enhanced Raman spectroscopy (SERS) coupled with principal component analysis (PCA) can serve as a fast, reliable, and easy method for detection and identification of food-borne bacteria, namely Salmonella spp., Listeria monocytogenes, and Cronobacter spp., in different types of food matrices (salmon, eggs, powdered infant formu...

This paper presents a study on sensing capabilities of stacks of nano-films deposited on a single-mode optical fiber's end face for application in label-free bio-recognition. The stack consist of five nano-films of periodically interchanging materials characterized by different refractive indices (n at λ = 1550 nm), aluminum Al <sub xmlns:mml="http...

This work presents an application of sodium hydroxide (NaOH) as an effective method for regeneration of titanium oxide (TiOx) nano-coated long-period grating (LPG) biosensor. Below 100 nm in thickness TiOx coating was deposited with atomic layer deposition (ALD) method on LPGs for enhancing their refractive index sensitivity up to 2912 nm/RIU in RI...

Carbon based nanocomposites have recently been intensively investigated as a new class of functional hybrid materials. Here, we present a procedure to obtain a new nanocomposite material made of carbon, boron and gold for applications in electrochemistry and electronics. The presented fabrication protocol uses cellulose fibers as a template that is...

The electrocatalytic oxidation of neurotransmitters on the electrodes modified with oppositely charged carbon nanoparticles has been investigated. These nanoparticles were deposited at the electrode from the aqueous suspensions via a layer-by-layer method. The electrocatalytic response was evaluated by cyclic voltammetry, differential pulse voltamm...

There is a continuous need for the construction of detection systems in microfluidic devices. In particular, electrochemical detection allows the separation of signals from the analyte and interfering substances in the potential domain. Here, a simple microfluidic device for the sensitive and selective determination of dopamine in the presence of i...

The charge transfer processes across the interface between two immiscible electrolyte solutions (ITIES) can be employed for energy storage and conversion, solvent extraction, or sensing or in life sciences. Among them are catalytic reactions, which have only been recently studied. Here H 2 O 2 generation is studied with decamethylferrocene (DMFc) a...

Carbon nanoparticulate film electrodes were prepared by alternative immersion of indium tin oxide plates into suspension of positively and negatively charged carbon nanoparticles. Their average thickness is in the range of 30–300 nm as determined by atomic force microscopy and depends on the number of immersion and withdrawal steps. After adsorptio...

Bilirubin oxidase was immobilised on ITO electrodes: bare or covered by ITO nanoparticulate film. The latter material was obtained by immersion and withdrawal of the substrate into ITO nanoparticles suspension. Formation of a protein deposit was confirmed by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy....

Voltammetry of manganese tetraphenylporphyrinato chloride in trihexyl(tetradecyl)phosphonium tris(pentafluoroe-thyl)trifluorophosphate solution in toluene reveals its unexpectedly low diffusion coefficient. UV-vis spectra confirm significant Cl À exchange with large phosphate anion at the axial position of the complex. Experiments performed with a...

The electrooxidation of two lignin model compounds – vanillyl alcohol and its dimer 1-(4-benzyloxy-3-methoxyphenyl-2-(2-methoxyphenoxy)-2-hydroxy-1-ethanol were studied. The products of this reaction were identified electrochemically and spectroscopically. For this purpose both compounds were encapsulated as part of two different electrode structur...

New macrobicyclic calix[4]amidocrowns (9-12) and macrotricyclic calix[4]amidocryptands (13, 14) have been obtained by reaction of a calix[4]arene derivative containing two distal acid chloride groups at the wide rim (8) with appropriate diamines. Their ionophoric properties were checked in PVC membranes. The calix[4]amidocrowns 10-12 did not alter...

Since 2000, ionic liquids are used for electrode modification. When these ionic liquid modified electrodes are immersed into aqueous solution, a well defined ionic liquid | aqueous electrolyte interface is formed. Here, the papers reporting on ion transfer across this interface are reviewed. This process is generated either by the electrochemical r...

Voltammetrically stable water insoluble 3,5-dimethoxy-4-hydroxybenzaldehydrazine (syringaldazine) modified electrode was obtained by sol–gel processing of methyltrimethoxysilane based sol with dissolved syringaldazine together with dispersed graphite particles. This silicate carbon ceramic electrode exhibits stable voltammetry corresponding to the...

Voltametrically stable 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS2−) modified electrode was obtained by sol–gel processing of methyltrimethoxysilane based sol with dissolved ABTS2− together with dispersed graphite particles. Next, extracellular laccase from Cerrena unicolor was encapsulated within a thin hydrophilic tetramethoxysilane...

The electrochemical behaviour of redox probe – t-butylferrocene dissolved in drop of o-nitrophenyloctylether based tetraalkylammonium salt solution, deposited on gold disc or used as a binder of carbon paste electrode, was studied in aqueous solution by cyclic voltammetry and differential pulse voltammetry. The electrochemical generation of t-butyl...

A thin film of carbon nanofibers embedded into a hydrophobic sol–gel material and deposited onto tin-doped indium oxide substrate electrodes is employed as a support for liquid|liquid redox systems. The system 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide|aqueous electrolyte is studied with t-butylferrocene as an electrochemically a...

Biphasic electrodes based on the water-insoluble redox liquid N,N-didodecyl-N′,N′-diethylphenylene-diamine (DDPD) neat and dissolved in di-(2-ethyl-hexyl)phosphate (HDOP) deposited onto silicate matrices were prepared and studied in aqueous electrolyte media. As electrode substrates (i) bare gold, (ii) a gold surface covered with a hydrophobic sili...

Ion transfer across the boundary formed at an ionic liquid drop deposited on an electrode immersed in aqueous solution, generated by electrochemical redox reaction at the electrode-ionic liquid interface, is studied to obtain information about the ability of anions to be transferred into a room temperature ionic liquid.

The electrode based on silicate carbon composite material was modified with redox probe (t-butylferrocene) solution in ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate or 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide). After immersion into an aqueous solution it was studied by cyclic voltammetry. It exhibits electrochem...

Hydrophobic sol-gel films from methyltrimethoxysilane (MTMOS) are deposited onto glass and tin-doped indium oxide (ITO) coated glass substrates. Uniform and microporous films of ca. 200 nm thickness are obtained and investigated by scanning electron microscopy and by electrochemical techniques. From cyclic voltammograms for the oxidation of ferroce...

The synthesis and single-crystal X-ray structures of the hydroxo-bridged complexes (m-hydroxo)-bis(octaethylporphinato)-gallium(III)perchlorate {[Ga(OEP)] 2 OH}ClO 4 and (m-hydroxo)-bis(octaethylporphinato)indium(III)tetrakis[3,5-bis-(trifluoro-methyl)phenyl]borate {[In(OEP)] 2 OH}TFPB are reported. These complexes are prepared by the titration of...

A novel transduction chemistry for preparing optical anion-selective polymeric films that respond reversibly and selectively to chloride ion activity is demonstrated. The chloride sensors are prepared by casting thin (5-10 microm) plasticized PVC films containing indium(III) octaethylporphyrin hydroxide, along with optimized levels of a lipophilic...

Plasticized poly(vinyl chloride) (PVC) optode membranes containing novel calix[4]arene chromoionophores 1 or 2 and one equivalent of a lipophilic anion respond to Pb2+ ions with high selectivity over alkali, alkaline-earth, and other heavy metal ions. This selectivity stems from the combination of ligand specificity and a unique ion exchange scheme...

The potentiometric response characteristics (slope and selectivity) of salicylate-selective electrodes based on Sn(IV) and OMo(V) (oxomolybdenum) tetraphenylporphyrins (TPP) in o-nitrophenyloctylether plasticized poly(vinyl chloride) membranes are compared. Super-Nernstian salicylate responses (slopes>−100 mV decade−1) are observed for membranes d...

The applications of thermochromic compounds (cobalt chloride, 3,5-dinitro salicylic acid) for fibre optic temperature sensors are presented. The sensors are based on thermochromic layers which utilise solution or polymeric foil made of polyHEMA. Spectral properties of the compounds were determined in an array spectrophotometer in order to choose an...

The paper is focused on lipophilic acyclic thioethers as neutral ionophores for heavy-metals cations. Membranes based on plasticized PVC containing these carriers exhibited high selectivity toward silver cations over transition metal ions (log KAgM < -4.5) except mercury ions. Membrane containing the ionophore II (with l-naphtyl pendant group) was...

 New macrobicyclic calix[4]amidocrowns (9–12) and macrotricyclic calix[4]amidocryptands (13, 14) have been obtained by reaction of a calix[4]arene derivative containing two distal acid chloride groups at the wide rim (8) with appropriate diamines. Their ionophoric properties were checked in PVC membranes. The calix[4]amidocrowns 10–12 did not alter...

A multiparameter fiber optic probe was designed to test drinking water. The probe consists of pH, temperature and calcium ions sensors, which are based on the absorbance changes of an appropriate reagent. The sensors are combined in a form of the head made from Teflon. Light emitting diodes (LEDs) are used as light sources and they are matched to...

Assessment of water quality based on multiparameter fiber optic probe A multiparameter fiber optic probe was designed to test drinking water. The probe consists of pH, temperature and calcium ions sensors, which are based on the absorbance changes of an appropriate reagent. The sensors are combined in a form of the head made from Teflon. Light em...

Assesment of water quality based on multiparameter fiber optic probe January 1998; Sensors and Actuators B Physical 51:208-213; Artur Dybko, Wojciech Wróblewski, Ewa Rozniecka, Zbigniew Brzózka, Ryszard Romaniuk

The paper presents an efficient technique for the preparation of pH-sensitive bulk optomembranes for fiber optic chemical sensors (FOCS). The method is based on the physical entrapment of the reagent molecules in the bulk of cellulose acetate membranes. The durable immobilization of a pH indicator is achieved by the addition of an appropriate ion-b...