33 research outputs found
Live cell imaging by 3-imino-(2-phenol)-1,8-naphthalimides : the effect of ex vivo hydrolysis
A series of 3-amino-N-substituted-1,8-naphthalimides and their salicylic Schiff base derivatives were synthesized.
The structure of the obtained compounds was confirmed using 1H and 13C NMR, FT-IR spectroscopy and
elemental analysis and COSY and HMQC for the representative molecules. The photophysical (UVâVis, PL) and
biological properties of all of the prepared compounds were studied. It was found that the amine with the nhexyl
group in EtOH had the highest PL quantumyield (Đ€=85%) compared to the others.Moreover, the chelating
properties of the azomethines with the n-hexyl group (1a, 1b, 1c) were tested against various cations (Al3+,
Ba2+, Co2+, Cu2+, Cr3+, Fe2+, Fe3+,Mn2+, Ni2+, Pb2+, Sr2+ and Zn2+) in an acetonitrile, acetone and PBS/AC mixture.
Compounds that contained the electron withdrawing groups (-Br, -I) had the ability to chelate most of the
studied cations, while the unsubstituted derivative chelated only the trivalent cations such as Al3+, Cr3+ and
Fe3+ in acetonitrile. The effect of the environment on the keto-enol tautomeric equilibrium was also demonstrated,
especially in the case of the derivativewith a bromine atom. The biological studies showed that the tested
molecules had no cytotoxicity. Additionally, the ability to image intracellular organelles such as the mitochondria
and endoplasmic reticulum was revealed. The crucial role of the hydrolysis of imines for cellular imaging was
presented
Unique properties of silver and copper silica-based nanocomposites as antimicrobial agents
The paper reports a new route for the fabrication and determination of physicochemical properties and
biological activity, of metallic silica-based nanostructure (Ag/SiO2, Cu/SiO2). A research studies shows
mono-dispersed nanoparticles in silica matrix with an average size of 12 nm for silver, as well as 12 nm
and 4 nm, respectively for copper in hydrophobic and hydrophilic silica composites. The chemical
analysis highlights metallic silver and copper ions heterogeneously distributed in the composite as well
as metallic oxides such as Ag2O, Cu2O and CuO in hydrophobic system, and CuO in hydrophilic one.
Structural research evidences the presence of amorphous, stoichiometric and non-stoichiometric
crystalline phase of silica. Biological studies reveal potentially inhibition of growth gram-positive and
gram-negative bacteria as well as microscopic fungi. The size of metal nanoparticles and level of silica
hydrophobicity show the highest inhibition bacterial growth for hydrophilic system with embedding
inside them, 4 nm in size copper nanoparticles. Finally, cytotoxic interaction against human cells with
respect to silver and copper silica-based nanocomposites was not found
Luminescence and electrochemical activity of new unsymmetrical 3- imino-1,8-naphthalimide derivatives
A new series of 1,8-naphtalimides containing an imine bond at the 3-position of the naphthalene
ring was synthesized using 1H, 13C NMR, FTIR, and elementary analysis. The impact of the
substituent in the imine linkage on the selected properties and bioimaging of the synthesized compounds
was studied. They showed a melting temperature in the range of 120â164 C and underwent
thermal decomposition above 280 C. Based on cyclic and differential pulse voltammetry, the electrochemical
behavior of 1,8-naphtalimide derivatives was evaluated. The electrochemical reduction
and oxidation processes were observed. The compounds were characterized by a low energy band
gap (below 2.60 eV). Their photoluminescence activities were investigated in solution considering
the solvent effect, in the aggregated and thin film, and a mixture of poly(N-vinylcarbazole) (PVK)
and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) (50:50 wt.%). They demonstrated low
emissions due to photoinduced electron transport (PET) occurring in the solution and aggregation,
which caused photoluminescence quenching. Some of them exhibited light emission as thin films.
They emitted light in the range of 495 to 535 nm, with photoluminescence quantum yield at 4%.
Despite the significant overlapping of its absorption range with emission of the PVK:PBD, incomplete
Förster energy transfer from the matrix to the luminophore was found. Moreover, its luminescence
ability induced by external voltage was tested in the diode with guestâhost configuration. The
possibility of compound hydrolysis due to the presence of the imine bond was also discussed, which
could be of importance in biological studies that evaluate 3-imino-1,8-naphatalimides as imaging
tools and fluorescent materials for diagnostic applications and molecular bioimaging
1,8-Naphthalimides 3-substituted with imine or ÎČ-ketoenamine unit evaluated as compounds for organic electronics and cell imaging
In this paper, we describe both new as well as described in our previous works 1,8-
naphthalimide derivatives substituted at the 3-C position with imine or -ketoenamine unitin
order to demonstrate a broader scope of research enabling of analysis between the structureproperties
relationship relevant to the application of these compounds in organic electronics and
cellular imaging. Thermal, physicochemical, optical, electrochemical, electroluminescence, and
biological properties of a series of derivatives containing the 1,8-naphthalimideunit were tested
and compared. This allowed the determination of impact of substituents in the imide part
(hexylamine, phenylethyl, benzyl, fluorobenzyl, methylbenzyl), type of bond (imine or
ketoenamine) as well as the substituent on the naphthalene ring (2-hydroxyphenyl, 5-bromo-2-
hydroxyphenyl, 3,5-diodo-2-hydroxyphenyl, pyrimidines) on their properties. Moreover, the
properties in the aggregating state were tested in the MeOH/PBS system. Imines are susceptible
to the hydrolysis process and aggregation-caused photoluminescence quenching(ACQ). In
turn,-ketoenamine shown excited-state intramolecular proton transfer promoted by aggregation
(AIEE). Our studies can be helpful in the further design of compounds containing the 1,8-
naphthalimide structure for various applications
Effect of the complex-formation ability of thiosemicarbazones containing (aza)benzene or 3-nitro-1,8-naphthalimide unit towards Cu(II) and Fe(III) ions on their anticancer activity
We recently described a novel class of thiosemicarbazones (TSCs) with a high anticancer activity. Now, we
expanded this compound library with a new class of TSCs with a 3-nitro-1,8-naphthalene unit. Thus, a series of
novel TSC conjugates was obtained to determine the effect of its chemical structure on spectroscopic properties,
metal complexing and biological activity. They were prepared in a microwave reactor, provided compounds with
both a high yield and purity. Nuclear magnetic resonance (1H and 13C NMR, COSY, HMQC) and infrared
spectroscopy were used to characterize them structurally. Additionally, DFT calculations were performed in
order to obtain the optimized ground-state geometry. Physicochemical spectroscopic studies were conducted in
different solvents and conditions to assess the effect of the substituent on the optical properties and metal
complexing ability. The anticancer activity was tested on three cancer cell lines and then correlated with the
spectroscopic results. Here, we show based on in vitro chelating studies, that anticancer activity is closely
correlated with the Fe3+ and Cu2+ chelating ability of these compounds
Synthesis and applications of [60]fullerene nanoconjugate with 5- aminolevulinic acid and its glycoconjugate as drug delivery vehicles
The 5-aminolevulinic acid (5-ALA) prodrug is widely used in clinical applications, primarily for skin cancer
treatments and to visualize brain tumors in neurosurgery. Unfortunately, its applications are limited by
unfavorable pharmacological properties, especially low lipophilicity; therefore, efficient nanovehicles are
needed. For this purpose, we synthesized and characterized two novel water-soluble fullerene
nanomaterials containing 5-ALA and D-glucuronic acid components. Their physicochemical properties
were investigated using NMR, XPS, ESI mass spectrometry, as well as TEM and SEM techniques. In
addition, HPLC and fluorescence measurements were performed to evaluate the biological activity of
the fullerene nanomaterials in 5-ALA delivery and photodynamic therapy (PDT); additional detection of
selected mRNA targets was carried out using the qRT-PCR methodology. The cellular response to the
[60]fullerene conjugates resulted in increased levels of ABCG2 and PEPT-1 genes, as determined by
qRT-PCR analysis. Therefore, we designed a combination PDT approach based on two fullerene
materials, C60-ALA and C60-ALA-GA, along with the ABCG2 inhibitor Ko143
High pressure as a novel tool for the cationic ROP of Îł-butyrolactone
In this study, we report the acid-catalyzed and high pressure assisted ring-opening polymerization (ROP) of
g-butyrolactone (GBL). The use of a dually-catalyzed approach combining an external physical factor and
internal catalyst (trifluoromethanesulfonic acid (TfOH) or p-toluenesulfonic acid (PTSA)) enforced ROP of
GBL, which is considered as hardly polymerizable monomer still remaining a challenge for the modern
polymer chemistry. The experiments performed at various thermodynamic conditions (T ÂŒ 278â323 K
and p ÂŒ 700â1500 MPa) clearly showed that the high pressure supported polymerization process led to
obtaining well-defined macromolecules of better parameters (Mn ÂŒ 2200â9700 g mol 1; Ä ÂŒ 1.05â1.46)
than those previously reported. Furthermore, the parabolic-like dependence of both the molecular
weight (MW) and the yield of obtained polymers on variation in temperature and pressure at either
isobaric or isothermal conditions was also noticed, allowing the determination of optimal conditions for
the polymerization process. However, most importantly, this strategy allowed to significantly reduce the
reaction time (just 3 h at room temperature) and increase the yield of obtained polymers (up to 0.62
gPGBL/gGBL). Moreover, despite using a strongly acidic catalyst, synthesized polymers remained non-toxic
and biocompatible, as proven by the cytotoxicity test we performed in further analysis. Additional
investigation (including MALDI-TOF measurements) showed that the catalyst selection affected not only
MW and yield but also the linear/cyclic form content in obtained macromolecules. These findings show
the way to tune the properties of PGBL and obtain polymer suitable for application in the biomedical
industry
Electronic Speckle Pattern Interferometry for Vibrational Analysis of Cutting Tools
A Michelson interferometer based ESPI system for static and vibration out of plane displacement measurements is presented. The aim of the article is to demonstrate the usability of ESPI non-contact measurement method in the field of machining. The correlation fringe patterns were visualized using custom software. The accuracy of ESPI interferometer was verified by the comparison with measurement results collected using industrial XL-80 laser system. The efficacy in vibration analysis was tested by studying the mode shapes and resonant frequencies of the transverse vibrations of square plates. The measurement methodology was used to determine natural frequencies and the shapes of vibrational modes of NFTe 100x1.2/64-II circular slitting saw. As a result the values of rotational speed that should be avoided during machining were determined
FĂ„rö, Bergmanâs Island
This paper is an attempt to investigate the relationship between Ingmar Bergman, the Swedish auteur and the island of FĂ„rö in the Baltic, where he worked and lived for 40 years. Bergman said: âIf one wished to be solemn, it could be said that I had found my landscape, my real home; if one wished to be funny, one could talk about love at first sight.â He discovered the island when looking for a location to shoot Through a Glass Darkly. Including Through a Glass Darkly, Bergman was to shoot six films and one television series on FĂ„rö. He also made two documentary films about the island and its inhabitants: FĂ„rö Document 1969 and FĂ„rö Document 1979
Sensitivity Analysis of Single- and Bimetallic Surface Plasmon Resonance Biosensors
Comparative analysis of the sensitivity of two surface plasmon resonance (SPR) biosensors was conducted on a single-metallic Au sensor and bimetallic AgâAu sensor, using a cathepsin S sensor as an example. Numerically modeled resonance curves of Au and AgâAu layers, with parameters verified by the results of experimental reflectance measurement of real-life systems, were used for the analysis of these sensors. Mutual relationships were determined between âY/ân components of sensitivity of the Y signal in the SPR measurement to change the refractive index n of the near-surface sensing layer and ân/âc sensitivity of refractive index n to change the analyteâs concentration, c, for both types of sensors. Obtained results were related to experimentally determined calibration curves of both sensors. A characteristic feature arising from the comparison of calibration curves is the similar level of Au and AgâAu biosensorsâ sensitivity in the linear range, where the signal of the AgAu sensor is at a level several times greater. It was shown that the influence of sensing surface morphology on the ân/âc sensitivity component had to be incorporated to explain the features of calibration curves of sensors. The shape of the sensory surface relief was proposed to increase the sensor sensitivity at low analyte concentrations