Ion Ionescu Of La Brad University

Mihail Kogălniceanu, Romania

Ion Ionescu Of La Brad University

Mihail Kogălniceanu, Romania

Time filter

Source Type

Marin L.,Petru Poni Institute of Macromolecular Chemistry | Ailincai D.,Petru Poni Institute of Macromolecular Chemistry | Mares M.,Ion Ionescu Of La Brad University | Paslaru E.,Petru Poni Institute of Macromolecular Chemistry | And 4 more authors.
Carbohydrate Polymers | Year: 2015

The paper reports the preparation of twelve imino-chitosan biopolymer films by acid condensation of the amino groups of chitosan with various aldehydes, in aqueous medium, followed by slow water removal. FTIR spectroscopy has shown drastic conformation changes of chitosan macromolecular chains - from a stiff coil to a straight one, while wide angle X-ray diffraction evidenced a layered morphology of the biopolymer films. Contact angle and surface free energy determination indicated a higher biocompatibility of the new biopolymers as compared to the chitosan parent, while the microbiological screening demonstrated their self-defense properties against common and virulent pathogen agents. It was concluded that the reversibility of imine forming promotes the self-assembling of imino-chitosan biopolymer films into a lamellar morphology and, on the other hand, the slow release of the antimicrobial aldehyde in the microbiological culture. The obtained results demonstrate that chitosan polyamine is a challenging workbench to functional biodynamic materials. © 2014 Elsevier Ltd. All rights reserved.


Racles C.,Petru Poni Institute of Macromolecular Chemistry | Racles C.,Technical University Gheorghe Asachi | Mares M.,Ion Ionescu Of La Brad University | Sacarescu L.,Petru Poni Institute of Macromolecular Chemistry
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2014

The aqueous dissolution of a poorly soluble drug nystatin (Nys) was achieved by a simple, excipient-free procedure using a tromethamol-modified polysiloxane (ST) as surfactant. Long-term stable Nys aqueous formulation was prepared and investigated by different methods, in order to understand the mechanism of drug solubilization. The cryo-TEM analysis revealed the presence of soft vesicles in the Nyst_ST solution. According to TEM measurements, the drug is contained in the hydrophobic layer of the surfactant vesicles. The dynamic light scattering (DLS) measurements on Nys_ST showed a main population around 134. nm having the Zeta potential of 33.3. mV. FT-IR, UV-vis, and thermogravimetric (TG-DTG-DTA) data point toward physical encapsulation, accompanied by a decrease of H-bonding between the drug molecules. The antifungal activity tested in vitro toward four yeast strains was seriously improved compared to the aqueous dispersion of the native drug, although the availability was diminished compared to DMSO solution. © 2013 Elsevier B.V.


Marin L.,Petru Poni Institute of Macromolecular Chemistry | Stoica I.,Petru Poni Institute of Macromolecular Chemistry | Mares M.,Ion Ionescu Of La Brad University | Dinu V.,Petru Poni Institute of Macromolecular Chemistry | And 4 more authors.
Journal of Materials Chemistry B | Year: 2013

Vanillin-chitosan biodynamers have been prepared and structure-morphology correlations revealed the pathway of progressive incorporation of the aldehyde onto chitosan backbones. Such dynamic biopolymers or biodynamers, generated from reversibly interacting components, offer the possibility to address the dynamic covalent behaviour of the reversible imine-bond formation/hydrolysis equilibria between vanillin and chitosan polymeric backbones. The reaction takes place with very low conversion in acidic aqueous solutions (7-12%), but the imine bond formation is amazingly improved (∼80%) when the reaction takes place while solution-solid state transition and solid state phase-organization events occur. The chitosan-vanillin biopolymeric films described here present interesting Candida albicans antifungal activity compared with other common bacterial strands, which suggests the implementation of these biocompatible materials as thin layer protecting systems for medical devices. © 2013 The Royal Society of Chemistry.


Kolecka A.,Fungal Biodiversity Center | Khayhan K.,Fungal Biodiversity Center | Khayhan K.,University of Phayao | Groenewald M.,Fungal Biodiversity Center | And 9 more authors.
Journal of Clinical Microbiology | Year: 2013

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used for an extensive identification study of arthroconidial yeasts, using 85 reference strains from the CBS-KNAW yeast collection and 134 clinical isolates collected from medical centers in Qatar, Greece, and Romania. The test set included 72 strains of ascomycetous yeasts (Galactomyces, Geotrichum, Saprochaete, and Magnusiomyces spp.) and 147 strains of basidiomycetous yeasts (Trichosporon and Guehomyces spp.). With minimal preparation time, MALDI-TOF MS proved to be an excellent diagnostic tool that provided reliable identification of most (98%) of the tested strains to the species level, with good discriminatory power. The majority of strains were correctly identified at the species level with good scores (>2.0) and seven of the tested strains with log score values between 1.7 and 2.0. The MALDI-TOF MS results obtained were consistent with validated internal transcribed spacer (ITS) and/or large subunit (LSU) ribosomal DNA sequencing results. Expanding the mass spectrum database by increasing the number of reference strains for closely related species, including those of nonclinical origin, should enhance the usefulness of MALDI-TOF MS-based diagnostic analysis of these arthroconidial fungi in medical and other laboratories. Copyright © 2013, American Society for Microbiology.


Simionescu B.,Petru Poni Institute of Macromolecular Chemistry | Bordianu I.-E.,Petru Poni Institute of Macromolecular Chemistry | Aflori M.,Petru Poni Institute of Macromolecular Chemistry | Doroftei F.,Petru Poni Institute of Macromolecular Chemistry | And 4 more authors.
Materials Chemistry and Physics | Year: 2012

The paper reports the first study on hierarchical assemblies (nanofibrillar micelles confined within semi-cylindrical shells) with silsesquioxane and quaternary ammonium units obtained through polymer blending intended for antimicrobial/antifungal stone coatings. The formation of hierarchical structures on solid surfaces is due to the multiple intermolecular ionic interactions, intermolecular Van der Waals and hydrophobic interactions acting among the component molecules. Their antimicrobial/antifungal properties toward the Gram-negative bacteria, Escherichia coli, Gram-positive bacteria, Staphylococcus aureus, and Candida albicans fungus were determined in aqueous solution and were found to be strongly dependent of the topographical features of the coating. © 2012 Elsevier B.V. All rights reserved.


Roman G.,Petru Poni Institute of Macromolecular Chemistry | NAstasA V.,Ion Ionescu Of La Brad University | BostAnaru A.-C.,Ion Ionescu Of La Brad University | Mares M.,Ion Ionescu Of La Brad University
Bioorganic and Medicinal Chemistry Letters | Year: 2016

A small library of 1-aminoalkyl 2-naphthols has been synthesized through the direct Mannich reaction of 2-naphthols with (hetero)aromatic aldehydes and secondary amines. All of the Mannich bases having a thiophen-2-yl ring in their structure had good activity against Gram-positive bacteria, irrespective of the nature of the amino moiety. © 2016 Elsevier B.V. All rights reserved.


PubMed | Ion Ionescu Of La Brad University and Petru Poni Institute of Macromolecular Chemistry
Type: Journal Article | Journal: Results in pharma sciences | Year: 2015

A novel inclusion complex of the propiconazole nitrate (NO3PCZ) with -cyclodextrin (-CD) was prepared by treatment of propiconazole (PCZ) with an acidic nitrating agent. The formation of NO3PCZ and its inclusion complex with -CD has been studied by NMR, ESI-MS, TGA, DSC methods. Using the undecoupled signal in the HMBC correlation spectra, almost identical coupling constants of CH from trizolic ring of PCZ and NO3PCZ compounds ((1)J(HC)3=207Hz, (1)J(CH)5=214Hz, for PCZ; (1)J(HC)3=208Hz and (1)J(CH)5=215Hz, for NO3PCZ) were determined, confirming that the geometry of the heterocyclic skeleton is identical in both the forms. The 1:1 stoichiometry of the complex was determined by ESI-MS and was confirmed using Scotts equation in DMSO and Higuchi and Connors equation in water. The solubility curve obtained for NO3PCZ in presence of -CD in distilled water was constructed, resulting in a solubility diagram of AL type. Solubility of NO3PCZ in water was determined by DLS studies. The results showed that NO3PCZ was encapsulated within the -CD cavity with a binding constant of 330 M-1 in DMSO and 975 M-1 in water. Preliminary pharmacological studies showed higher antifungal activities for NO3PCZ and its inclusion complex, compared with its PCZ analog. The acute toxicity of the complex is smaller than the pure or modified drug, recommending the inclusion complex as future promising therapeutic agents.


PubMed | Ion Ionescu Of La Brad University and Petru Poni Institute of Macromolecular Chemistry
Type: | Journal: Carbohydrate polymers | Year: 2016

Chitosan based hydrogels are a class of cross-linked materials intensely studied for their biomedical, industrial and environmental application, but their biomedical use is limited because of the toxicity of different organic crosslinkers. To overcome this disadvantage, a new strategy to produce supramolecular chitosan hydrogels using low molecular weight compounds able to form covalent linkages and H-bonds to give a dual crosslinking is proposed. For this purpose we used 2-formylphenylboronic acid, which brings the advantage of imine stabilization via iminoboronate formation and potential antifungal activity due to the presence of boric acid residue. FTIR and NMR spectroscopy indicated that the gelling process took place by chemo-physical crosslinking forming a dual iminoboronate-chitosan network. Further, X-ray diffraction demonstrated a three-dimensional nanostructuring of the iminoboronate network with consequences on the micrometer-scale morphology and on the improvement of mechanical properties, as demonstrated by SEM and rheological investigation. The hydrogels proved strong antifungal activity against Candida planktonic yeasts and biofilms, promising to be a friendly treatment of the recurrent vulvovaginitis infections.


PubMed | Ion Ionescu Of La Brad University, Petru Poni Institute of Macromolecular Chemistry and Dental Office
Type: Journal Article | Journal: Dental materials : official publication of the Academy of Dental Materials | Year: 2016

To achieve bisphenol A glycerolate dimethacrylate (BisGMA) analogs with reduced viscosity to be used in the formulation of dental adhesives containing biocidal components.A series of low-viscosity BisGMA derivatives (: 39-12Pas) modified with 30, 60 and, respectively 80mol% carboxylic acid units were synthesized and characterized. Hydrogen bonding interactions in our monomers, the photopolymerization behavior and implicitly the conversion degree (DC) for some experimental adhesive formulations containing acid-modified BisGMA, commercial BisGMA (only in F1-F3), triethyleneglycol dimethacrylate and 2-hydroxyethyl methacrylate were examined by FTIR spectroscopy. The water effects on the photocrosslinked networks together with the flexural strength/modulus were also investigated. The adhesive penetration into the dentin surface was surveyed by SEM analysis, and the antimicrobial activity triggered by the incorporation of 0.5wt% AgNOThe contribution of the hydrogen bonding interactions was found to be lower in BisGMA derivatives than in non-modified BisGMA, and the DC varied between 56.5 (F6) and 83.7% (F1) compared with a control formulation based on BisGMA:TEGDMA (DC=58.2%). The flexural strength and flexural modulus varied in the range 33.7MPa (F6)-54.4MPa (F8)MPa and 0.64 (F6)-1.43 (F8)GPa, respectively. SEM observation of adhesive-dentin interface revealed the formation of resin tags for the carboxyl-containing adhesive, while for the control adhesive they are hardly formed. Also, the microorganism development was inhibited, the proposed materials displaying antimicrobial activity.The experimental formulations based on carboxyl-functionalized BisGMA exhibit a similar or even improved behavior over control sample, suggesting their potential applicability as antimicrobial dental adhesives.


PubMed | Ion Ionescu Of La Brad University and Petru Poni Institute of Macromolecular Chemistry
Type: Journal Article | Journal: Bioorganic & medicinal chemistry letters | Year: 2016

A small library of 1-aminoalkyl 2-naphthols has been synthesized through the direct Mannich reaction of 2-naphthols with (hetero)aromatic aldehydes and secondary amines. All of the Mannich bases having a thiophen-2-yl ring in their structure had good activity against Gram-positive bacteria, irrespective of the nature of the amino moiety.

Loading Ion Ionescu Of La Brad University collaborators
Loading Ion Ionescu Of La Brad University collaborators