Antoni Kunicki

In vitro assessment of antibacterial properties and cytotoxicity of Al2O3–Ag nanopowders

Abstract Abstract The present paper describes an in vitro assessment of the antibacterial properties and cytotoxic activity on mammalian cells of silver nanoparticles incorporated into an aluminium nano-oxide substrate produced by the thermal decomposition–reduction method. The Al2O3–Ag nanopowders show good bactericidal and fungicidal properties. An Al2O3–Ag (12·55 wt-%) specimen at the concentration of 50 mg mL−1 reduced considerably the populations of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Bacillus subtilis species, whereas the same nanopowder in a concentration of 90 mg mL−1 inhibited significantly the growth of P. aeruginosa, E. coli, S. aureus and Candida albicans and also significantly limited the number of B. subtilis. The Al2O3–Ag nanoparticles also showed no cytotoxic effects on the three selected cell lines, i.e. L929, BJ and HeLa, and the cells remained >75% viability, as measured by MTT assay, and >102% viability, obtained by EZ4U assay, relative to control at concentration as high as 200 μg mL−1.

Al2O3–Ag nanopowders: new method of synthesis, characterisation and biocidal activity

Abstract Abstract The present paper describes an innovative method of producing silver nanoparticles incorporated into an aluminium nano‐oxide substrate. The method utilises thermal decomposition and reduction, which yields an Al2O3–Ag nanopowder with the average size of particles ranging from 43 to 60 nm and the average size of agglomerates between 330 and 870 nm. The average size of the silver nanoparticles incorporated in the aluminium nano‐oxide carrier ranges from 22 to 60 nm. The Al2O3–Ag nanopowders thus produced have a largely developed surface area (above 200 m2 g−1) with a great number of open pores (above 5×10−4 m3 g−1), which gives evidence that their tendency to agglomeration is only slight and that the possible agglomerates have a loose structure. Moreover, the nanopowders show good bactericidal and fungicidal properties. The results obtained in the present experiments show that the Al2O3–Ag nanopowders produced by the proposed method can be used successfully as the raw material in the production of biocidal biomaterials.

Impact of Al2O3 nanopowders characterised by various physicochemical properties on growth of green alga Scenedesmus quadricauda

Abstract This study estimates the influence of five Al2O3 nanopowders on the growth of Scenedesmus quadricauda depending on the physical and chemical properties of the alumina nanoparticles and on the concentration of the nanopowder. The agglomeration and crystallisation levels of the alumina nanopowders as well as the zeta potential, the conductivity and the pH of nanopowders-containing growth media are considered. The strongest algal growth inhibiting effect was accompanied by the highest degree of agglomeration and the highest crystallisation level as well as the smallest specific surface area.

Alkylaluminum Derivatives of Diphenic Acid: Novel Aluminum Carboxylates

The reaction of trialkylaluminum compounds with diphenic acid in a 2:1 molar ratio results in the formation of novel dialkylaluminum dicarboxylates [Et(4)Al(2)(OOCC(12)H(8)COO)](3) (1) and [(i)Bu(4)Al(2)(OOCC(12)H(8)COO)](2) (2). Molecular structures of the compounds have been determined by X-ray crystallography. Compound 1 is a hexamer with a skeleton framework consisting of four fused heterocyclic rings, one 27-membered and three Al(2)O(4)C(2) 8-membered. Compound 2 is a centrosymmetric tetramer with a skeleton framework consisting of three fused heterocyclic rings, one 18-membered and two Al(2)O(4)C(2) 8-membered. The structures of the compounds reveal R(4)Al(2)O(4)C(2) subunits, each linked through diphenyl C(12)H(8) bridges. Each of the aluminum atoms is bonded to two alkyl groups and two oxygen atoms originating from two different dicarboxylate moieties.

Nano-titanium oxide doped with gold, silver, and palladium — synthesis and structural characterization

Nano-titania doped with noble metals (Au/TiO2, Ag/TiO2, Pd/TiO2) has been synthesized by mild hydrolysis of the mixture of metal salts or complexes and titanium isopropoxide ((iPr-O)4Ti). After thermal decomposition of the obtained precursors, nanomaterials were formed. Morphological characterization of the nanomaterials was provided by scanning electron microscopy (SEM) and stereological analysis, determining the BET specific surface area, and BJH nanoporosity (pore volume, pore size). It has been found that the structure of nanomaterials (size of nanoparticles and agglomerates) depended strongly on the method of the (iPr-O)4Ti hydrolysis. A minor dependence on the kind of solvents and precursors of noble metals was observed. The presence of doping metal nanoparticles was confirmed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Nanomaterial phases were identified by X-ray diffraction (XRD). According to the XRD patterns, Ag/TiO2 and Pd/TiO2 products with doping metals in their oxidized form contain Ag-Ti and Pd-Ti phases. Peaks of the metal oxides Ag2O and PdO are absent in the XRD patterns. The average size of TiO2 nanoparticles is situated in the region of 20–60 nm, whereas metals are present as about 10–15 nm sized particles and fine nanoparticles.

The products formed in the reaction of MeAlCl2 with alcohols (1:1)

Abstract The products formed in the reaction (1:1) of MeAlCl2 with alcohols ROH, where R=Et, iPr, nBu, iBu, sBu, tBu, tBuCH2 were investigated. Depends on the alcohol used the formation of [Cl2Al(μ-OR)2]2AlCl or/and [Cl2Al(μ-OR)2]3Al except dimeric or/and trimeric ROAlCl2 were found. The products have been characterized by NMR and cryoscopically in benzene. The crystal structures of [Cl2Al(μ-OnBu)2]3Al and [Cl2Al(μ-OCH2tBu)]2 were determined by X-ray diffraction studies.

Synthesis, properties and crystal structure of bis(cyclopentadienyl) aluminium complex [ν1-(C5H5)2AlOiPr]2

Abstract The reaction of Cl 2 AlO i Pr with C 5 H 5 Na affords the isopropoxy-briged dimer [ ν 1 -(C 5 H 5 ) 2 AlO i Pr] 2 . The compound has been characterized by NMR and its crystal structure determined by X-ray diffraction study.

The factors controlling the reaction of (2,4,6-triisopropylphenyl) methyl ketone with Ph3Al and structure of [Ph2AlO(2,4,6-tri-iPr-C6H2)CCH2]2

Abstract The reaction of (2,4,6)-tri-isopropylphenyl methyl ketone with tri-phenylaluminium was investigated. [Ph 2 AlO(2,4,6-tri- i Pr-C 6 H 2 )CCH 2 ] 2 was found to be formed exclusively. The title compound has been characterised by NMR and its crystal structure determined by X-ray diffraction study.

The reactions of tetraalkylaluminoxanes with benzonitrile

Abstract The reactions of benzonitrile with tetraethylaluminoxane and with tetramethylaluminoxane in 1 : 1 molar ratio were studied. In the case of tetraethylaluminoxane 1,3,5-triphenyl-2,4-diaza-1-aminoheptadiene-1,4, Ph(Et)HCNC(Ph)NC(Ph)NH2, was found to be the main product after hydrolysis, 1,3-dipheny-2-aza-1-aminopentene-1, Ph(Et)HCNC(Ph)NH2,2,4,6-triphenylazine-1,3,5; 5-methyl-2,4,6-triphenylpyrimidine, propiophenone and benzaldehyde were also formed. A reaction scheme is proposed. In the case of Me4Al2O, acetophenone was formed as the main product after hydrolysis.

Electrospun Poly(L-lactic)Acid/Nanoalumina (PLA/Al2O3) Composite Fiber Mats with Potential Biomedical Application - Investigation of Cytotoxicity

PLA fibrous mats containing nanoalumina filler were fabricated by electrospinning method. The morphology of the mats was characterized by SEM, and TEM. In vitro biocompatibility of the electrospun fiber mats was also evaluated. Indirect cytotoxicity evaluation of the fiber mats with human skin fibroblasts revealed that the materials were non-toxic to living cells. The cells cultured on the fibrous mat exhibited normal cells shapes and were integrated well with surrounding fibers. The obtained results confirmed the potential for use of the electrosupun PLA/Al2O3 fiber mats for biomedical application.