Prof. Alexandre Loukanov, PhD - Saitama University - Professor

Prof. Alexandre Loukanov

PhD

Saitama University

Professor

Saitama-shi, Saitama-ken | Japan

Additional Specialties: Nanobiotechnology

ORCID logohttps://orcid.org/0000-0002-5029-7354

Prof. Alexandre Loukanov, PhD - Saitama University - Professor

Prof. Alexandre Loukanov

PhD

Introduction

Primary Affiliation: Saitama University - Saitama-shi, Saitama-ken , Japan

Additional Specialties:

Publications

20Publications

67Reads

13Profile Views

4PubMed Central Citations

Two-photon microscopy assessment of the overall energy metabolism alteration of amoeba in hypertonic environment.

Microsc Res Tech 2019 Jul 8. Epub 2019 Jul 8.

Division of Strategic Research and Development, Graduate School of Science and Engineering, Saitama University, Saitama, Japan.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.23338DOI Listing
July 2019
4 Reads
1.170 Impact Factor

Real time monitoring and quantification of uptake carbon nanodots in eukaryotic cells.

Microsc Res Tech 2018 Dec 8;81(12):1541-1547. Epub 2018 Nov 8.

Laboratory of Engineering NanoBiotechnology, Department of Engineering Geoecology, University of Mining and Geology "St. Ivan Rilski", Sofia, Bulgaria.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.23161DOI Listing
December 2018
2 Reads
1.170 Impact Factor

Positive Association between Gene and Susceptibility to Idiopathic Scoliosis in Bulgarian Population.

Anal Cell Pathol (Amst) 2018 18;2018:6836092. Epub 2018 Jul 18.

Graduate School for Science and Engineering, Saitama University, 255 Shimookubo, Sakura-ku, Saitama 338-8570, Japan.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1155/2018/6836092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6069583PMC
October 2018
10 Reads
1.760 Impact Factor

Visualization of the native shape of bodipy-labeled DNA in Escherichia coli by correlative microscopy.

Microsc Res Tech 2018 Mar 27;81(3):267-274. Epub 2017 Nov 27.

Graduate School of Science and Engineering, Saitama University, Shimo-Ohkubo 255, Sakura-Ku, Saitama, 338-8570, Japan.

View Article

Download full-text PDF

Source
http://doi.wiley.com/10.1002/jemt.22975
Publisher Site
http://dx.doi.org/10.1002/jemt.22975DOI Listing
March 2018
18 Reads
1.170 Impact Factor

Visualization of the native shape of bodipy-labeled DNA in Escherichia coli by correlative microscopy

Microscopy Research & Technique

The native shape and intracellular distribution of newly synthesized DNA was visualized by correlative (light and electron) microscopy in ice embedded whole cells of Escherichia coli. For that purpose, the commercially available modified nucleoside triphosphate named BODIPY® FL-14-dUTP was enzymatically incorporated in vivo into the genome of E. coli mutant K12 strain, which cannot synthesize thymine. The successful incorporation of this thymidine analogue was confirmed first by fluorescence microscope, where the cells were stained in the typical for bodipy green color. Later the preselected labeled E. coli were observed by Hilbert Differential Transmission Electron Microscope (HDC TEM) and the distribution of elemental boron (contained in bodipy) was visualized at high-resolution by an electron spectroscopic imaging (ESI) technique. The practical detection limit of boron was found to be around 5 10 mmol/kg in area of 0.1 lm2, which demonstrated that ESI is a suitable approach to study the cytochemistry and location of labeled nucleic fragments within the cytoplasmic chromosomal area. In addition, the fine cellular fibrous and chromosomal ultrastructures were revealed in situ by combing of phase-plate HDC TEM and ESI. The obtained results conclude that the correlation between fluorescent microscopy with phase-plate HDC TEM and ESI is a powerful approach to explore the structural and conformation dynamics of DNA replication machinery in frozen cells close to the living state.

View Article
December 2017
4 Reads

Monitoring and extraction of uranium in polluted acid mine drainage by super-paramagnetic nanoparticles coated with carbon nanodots

J Radioanal Nucl Chem

In this contribution, we designed environmentally friendly magnetic nanoparticles for simultaneously monitoring and efficiently extracting uranium (VI) from polluted acid mine drainage ([99% of the total uranium amount). The nanoparticles consist of super-paramagnetic core made of Fe3O4, which is chemically coated with highly-fluorescent shell made of carbon nanodots. The small nanoparticle diameter enables good water dispersibility, high mobility in suspension and powerful sorbent activity to U(VI) in the presence of sulfates, bicarbonates, and pH 4.3–4.8. The measured detection limit of uranium (VI) in model solutions of acid mine drainage was found to be around 0.8 ppm.

View Article
October 2017
2 Reads

Biotinylated vanadium and chromium sulfide nanoparticles as probes for colocalization of membrane proteins.

Microsc Res Tech 2016 Sep 17;79(9):799-805. Epub 2016 Jun 17.

Materials Research Laboratory, University of Nova Gorica, SI-5000, Slovenia.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.22701DOI Listing
September 2016
3 Reads
1.170 Impact Factor

Intracellular imaging of Qdots-labeled DNA in cyanobacteria.

Microsc Res Tech 2016 May 9;79(5):447-52. Epub 2016 Mar 9.

Graduate School of Science and Engineering, Saitama University, Shimo-Ohkubo 255, Sakura - Ku, Saitama, 338-8570, Japan.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.22651DOI Listing
May 2016
4 Reads
1.170 Impact Factor

Association Between IL-6 and MMP3 Common Genetic Polymorphisms and Idiopathic Scoliosis in Bulgarian Patients: A Case-control Study.

Spine (Phila Pa 1976) 2016 May;41(9):785-91

*National Genetic Laboratory, Department of Obstetrics and Gynecology, Faculty of Medicine, Medical University-Sofia†Tokuda Hospital Sofia, Orthopedic and Traumatology Clinic‡University Orthopedic Hospital "Prof. Boycho Boychev"§Molecular Medicine Center, Medical University-Sofia, Bulgaria||Graduate School of Science and Engineering, Saitama University, Japan.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1097/BRS.0000000000001360DOI Listing
May 2016
10 Reads
2 Citations
2.300 Impact Factor

Electron microscopic visualization of complementary labeled DNA with platinum-containing guanine derivative.

Microsc Res Tech 2016 Apr 25;79(4):280-4. Epub 2016 Jan 25.

Materials Research Laboratory, University of Nova Gorica, Nova Gorica, SI-5000, Slovenia.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.22628DOI Listing
April 2016
3 Reads
1.170 Impact Factor

Photosensitizer-Conjugated Ultrasmall Carbon Nanodots as Multifunctional Fluorescent Probes for Bioimaging

The Journal of Physical Chemistry C

Highly luminescent ultrasmall carbon nanodots (CDs) have been prepared by one-step microwave-assisted pyrolysis and functionalized with fluorescein photosensitizer by a diazo-bond. The absorption edge of such prepared fluorescein−N=N−CDs was red-shifted in comparison with the bare one. Nevertheless, the emission signal induced by the nanoparticle quantum-sized graphite structure was quenched due to photoisomerization of the diazo group at the photoexcited state. In order to restrict the photoisomerization, i.e., rotation around the nitrogen−nitrogen bond, the diazo group was fixed by a metal cation to form a complex compound or chelate. The obtained metal complex of fluorescein−N=N−CDs shows an absorbance maximum the same as bare CDs but a recovered emission signal from the nanoparticle moiety, which was bathochromically shifted. They exhibit lower quantum yield in comparison with the bare CDs but better photostability toward emission quenching in nutrition cell culture. The formed photosensitizer conjugated nanoprobes were proposed as multifunctional fluorophores for intracellular in vivo imaging due to their attractive photophysical attributes and tunable and excitation-dependent emission. The bioapplication of photosensitizer-conjugated CDs was demonstrated as fluorescent tracers for endocytosis pathways in cultured Tobacco cells. Their successful staining and lower toxicity to the plant cells were compared with conventional quantum dots (CdSe/ZnS core−shell type, which caused an acute toxicological in vivo effect).

View Article
April 2016
3 Reads

Immobilization and stretching of 5'-pyrene-terminated DNA on carbon film deposited on electron microscope grid.

Microsc Res Tech 2015 Nov 25;78(11):994-1000. Epub 2015 Aug 25.

Materials Research Laboratory, University of Nova Gorica, Nova Gorica, SI-5000, Slovenia.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.22564DOI Listing
November 2015
3 Reads
1.170 Impact Factor

High-resolution subunit detection of glutamate receptor by ultrasmall gold nanoparticles.

Microsc Res Tech 2012 Sep 28;75(9):1159-64. Epub 2012 Mar 28.

Laboratory of Engineering Nanobiotechnology, Department of Engineering Geoecology, University of Mining and Geology "St. Ivan Rilski," Stoyan Edrev Str., Sofia 1700, Bulgaria.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.22043DOI Listing
September 2012
3 Reads
1 Citation
1.170 Impact Factor

Immunolocalization of multiple membrane proteins on a carbon replica with STEM and EDX.

Ultramicroscopy 2010 Mar 10;110(4):366-74. Epub 2010 Feb 10.

School of Life Science, The Graduate University for Advanced Studies Sokendai, Okazaki 444-8787, Japan.

View Article

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ultramic.2010.01.016DOI Listing
March 2010
7 Reads
1 Citation
2.440 Impact Factor

Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

J Nanopart Res

The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600–1000 nm). They have been prepared by using both wet sol–gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications.

View Article
11 Reads

Simple way for preparation of ZnO films by surfactant mediated spray pyrolysis

Materials Science and Engineering B

Nanocrystalline porous ZnO films are deposited onto alumina foil substrates by polyvinyl alcohol (PVA) modified spray pyrolysis. Water and ethanol–water mixture were used for preparation of the sols. The effect of polyvinyl alcohol on the morphological and photocatalytical properties of ZnO films was studied. It was found that the polyvinyl alcohol plays important role in formation of porous films structure with ganglia like morphology. Relatively compact granular morphology was observed for the ZnO samples, grown without organic surfactant. The X-ray diffraction patterns revealed the formation of phase-pure ZnO thin films. The FTIR spectra and DTA-TG analyses of the precursor mixtures: Zn(CH3COOH)2·2H2O and Zn(NO3)2·6H20 with PVA revealed that ZnO is formed before the final decomposition of the polymer at 350 ◦C. It was observed that both: the acetate precursor and the organic surfactant could enhance significantly the photocatalytic properties of the ZnO films. The films obtained from sols, containing PVA showed better photocatalytic decolorization of Malachite Green dye, than the films, deposited from unmodified sols.

View Article
3 Reads

Synthesis of highly soluble phthalocyanine from a new phthalonitrile under mild conditions

Adv. Mat. Lett.

Novel syntheses of zinc phthalocyanine (ZnPc) are achieved by exploring our hexamethyldisilazane (HMDS) method. Reactions are clean and efficient by replacing harmful and strongly smelling triethylamine with HMDS. The compound is highly soluble in organic solvents and can be used as a donor material for organic thin film photovoltaic solar cells.

View Article
6 Reads

Carboxy-eosin as a marker for correlative light - electron microscopic imaging of newly synthesized in vivo DNA

Adv. Mat. Lett.

Here we report carboxy-eosin as a fluorescent marker for in vivo visualization of DNA in the correlative (fluorescence and electron) biological microscope. For that purpose a fluorescent thymidine analog 2’,4’,5’,7’-tetrabromofluorescein-aminoallyl-dUTP (eosin-aminoallyl-dUTP) was synthesized and incorporated into the genome of Escherichia coli. The fluorescent dye eosin contains four bromine atoms, which enable electron spectroscopic imaging in the transmission electron microscope. Labeled cells were prepared and directly observed by fluorescence and electron microscope without any preliminary fixation step. We demonstrated that eosin-aminoallyl-dUTP is a suitable marker for imaging of cell’s ultrastructures by correlative biological microscopy.

View Article
12 Reads

Photostability of Water-dispersible CdTe Quantum Dots: Capping Ligands and Oxygen

Chem. Lett.

Here we report the effect of various capping ligands on the optical properties and photostability of CdTe quantum dots in aqueous solutions. Ligand exchange procedure is used to prepare water dispersive CdTe nanocrystals capped with aminoethanethiol, 3-mercaptopropionic and dihydrolipoic acids. The dynamics of photoexcited states is examined by transient photoluminescent spectroscopy. Our results demonstrate that the luminescence intensity of water-dispersible CdTe quantum dots is strongly influenced by molecular oxygen under light irradiation.

View Article
3 Reads

Photoluminescence depending on the ZnS shell thickness of CdS/ZnS core-shell semiconductor nanoparticles

Colloids and Surfaces A: Physicochem. Eng. Aspects

A core/shell type semiconductor nanoparticle of CdS/ZnS emits visible light under ultra-violet illumination, whose emission wavelength depends on the particle diameter and ZnS shell thickness. This paper describes the dependence of the shell thickness on the amount of added ZnS precursor in the synthesis process and its impact on photoluminescence. The synthesis is done by the microemulsion method in AOT surfactant reverse micelles containing water. The precursor amount is varied by two different ways (1) increasing water content, at a given precursor concentration or (2) increasing the precursor concentration at given water content. It is found that the nanoparticle diameter and the shell thickness almost linearly increase when the water content trapped in the reverse micelles increases. Similarly, the diameter increases with the precursor concentration inside the micelles. The nanoparticle size also increases with the time of aging in an inert gas because of the increase of the ZnS shell thickness.

View Article
3 Reads

Top co-authors

Saim Emin
Saim Emin

University of Sofia

3
Polina Mladenova
Polina Mladenova

Laboratory of Engineering NanoBiotechnology

3
Seiichiro Nakabayashi
Seiichiro Nakabayashi

Saitama University

3
Chavdar Filipov
Chavdar Filipov

University of Forestry

2
Ivo Marinov Kremensky
Ivo Marinov Kremensky

Medical University Sofia

1
Hristo Gagov
Hristo Gagov

Sofia University St. Kliment Ohridski

1