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1.
J Mater Chem B ; 7(43): 6810-6821, 2019 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-31608920

RESUMO

Drug delivery systems based on the zeolitic imidazolate framework ZIF-8 have recently attracted viable research interest owing to their capability of decomposing in acidic media and thus performing targeted drug delivery. In vivo realization of this mechanism faces a challenge of relatively slow decomposition rates, even at elevated acidic conditions that are barely achievable in diseased tissues. In this study we propose to combine drug delivery nanocomposites with a semiconductor photocatalytic agent that would be capable of inducing a local pH gradient in response to external electromagnetic radiation. In order to test this principle, a model drug-releasing nanocomposite comprising photocatalytic titania nanotubes, ZIF-8, and the antitumor drug doxorubicin has been investigated. This system was demonstrated to release the drug in a quantity sufficient for effectively suppressing IMR-32 neuroblastoma cells that were used as a model diseased tissue. With locally applied UV irradiation, this result was achieved within 40 minutes, which is a relatively short time compared to the release duration in systems without photocatalyst, typically taking from several hours to several days.

2.
Nanoscale ; 11(13): 6343-6351, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30887996

RESUMO

In this study, we present a new concept for the simple visual detection of nano-scale objects in solutions. To achieve this goal, we developed chromogen-free interference-based sensors that provided a color visible reaction directly after the interaction of the analyte with the substrate. The effect is based on the strong optical interference occurring at the interface between the inkjet printed sol-gel titania film (a layer with high refractive index) and the adsorbed nano-sized objects (layer with low refractive index), which can be detected even with the naked eye. Herein, we have developed a synthetic strategy for the inkjet printing of interference sensors with controllable color change through thickness adjustment.

3.
Beilstein J Nanotechnol ; 9: 364-378, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29515950

RESUMO

We report on a new approach for the synthesis of TiO2-pillared montmorillonite, where the pillars exhibit a high degree of crystallinity (nanocrystals) representing a mixture of anatase and rutile phases. The structures exhibit improved adsorption and photocatalytic activity as a result of hydrothermally activated intercalation of titanium polyhydroxo complexes (i.e., TiCl4 hydrolysis products) in a solution with a concentration close to the sol formation limit. The materials, produced at various annealing temperatures from the intercalated samples, were characterized by infrared spectroscopy, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), X-ray diffraction, dynamic light scattering (DLS) measurements, and liquefied nitrogen adsorption/desorption. The photocatalytic activity of the TiO2-pillared materials was studied using the degradation of anionic (methyl orange, MO) and cationic (rhodamine B, RhB) dyes in water under UV irradiation. The combined effect of adsorption and photocatalysis resulted in removal of 100% MO and 97.5% RhB (with an initial concentration of 40 mg/L and a photocatalyst-sorbent concentration of 1 g/L) in about 100 minutes. The produced TiO2-pillared montmorillonite showed increased photocatalytic activity as compared to the commercially available photocatalyst Degussa P25.

4.
ACS Omega ; 3(12): 18803-18810, 2018 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31458443

RESUMO

Here, for the first time, we investigated the effects of matrixes with different nature on the stimuli-responsive mechanoluminescence (ML) of incorporated nanoparticles. It turned out that the contraction forces initiated by polymerization process can have compressive effects that differ by orders. This effect was achieved owing to the introduction of ML crystals in an alumina sol-gel system, which has large surface of coagulation contact. As one particle of boehmite results in a tension of 10-17-10-16 N per one particle of matrix, compared to 10-19 N of PDMS matrix, the threshold of mechanoluminescence was reached at 0.04 Pa, whereas the most active materials to date did not exceed this value. Thus, this material can be a perspective for the production of impact detectors, photonic displays of the next generation, and other advanced devices.

5.
Nanoscale ; 9(35): 13069-13078, 2017 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-28837196

RESUMO

We have demonstrated for the first time an inkjet fabrication of highly efficient luminescent structures based on Eu-doped ZrO2 nanocrystals (3.4 ± 0.3 nm), with a refractive index close to the one of the bulk materials. The nanoparticles were synthesised using a nonhydrolytic method in benzyl alcohol where the particles were post treated using acetic acid, leading to the formation of a stable colloid. It was shown that the non-polar methyl group of the acetic acid is responsible for its penetration through the hydrophobic layer all the way through to the surface of the ZrO2, leading to the cleavage of the Zr-OCH2C6H5 bond and the formation of surface acetate species and a concomitant decomposition of the zirconia superlattice. Hereby we show a new and efficient universal ink production through a multi-step process - starting from solvothermal synthesis, dispersion of nanocrystals in water, and adaptation of the rheological parameters of the resulting sols. Eventually, we were able to obtain inks that we used for the production of optical coatings, monolayer luminescent-protected holography and anti-counterfeiting printing. These structures, obtained at room temperature through inkjet printing, present dense xerogel structures with high optical transparency, a high refractive index and more efficient luminescence compared with the non-homogeneous structures produced as a mixture of rare-earth elements and nanocrystals.

6.
Adv Mater ; 29(12)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28112457

RESUMO

Synergistic combination of organic and inorganic nature in van der Waals metal-organic frameworks supports different types of robust excitons that can be effectively and independently manipulated by light at room temperature, and opens new concepts for all-optical data processing and storage.

7.
Sci Rep ; 6: 37090, 2016 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-27848979

RESUMO

This paper describes a practical approach for the fabrication of highly visible interference color images using sol-gel ink technique and a common desktop inkjet printer. We show the potential of titania-boehmite inks for the production of optical heterostructures on various surfaces, which after drying on air produce optical solid layers with low and high refractive index. The optical properties of the surface heterostructures were adjusted following the principles of antireflection coating resulting in the enhancement of the interference color optical visibility of the prints by as much as 32%. Finally, the presented technique was optimized following the insights into the mechanisms of the drop-surface interactions and the drop-on-surface coalescence to make it suitable for the production of even thickness coatings suitable for printing at a large scale. We propose that the technology described herein is a promising new green and sustainable approach for color printing.

8.
ACS Nano ; 10(3): 3078-86, 2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-26805775

RESUMO

Color printing technology is developing rapidly; in less than 40 years, it moved from dot matrix printers with an ink-soaked cloth ribbon to 3D printers used to make three-dimensional color objects. Nevertheless, what remained unchanged over this time is the fact that in each case, dye inks (CMYK or RGB color schemes) were exclusively used for coloring, which inevitably limits the technological possibilities and color reproduction. As a next step in printing color images and storing information, we propose the technology of producing optical nanostructures. In this paper, we report use of inkjet technology to create colored interference layers with high accuracy without the need for high-temperature fixing. This was made possible due to using titania-based colloidal ink yielding monolithic coatings with a high refractive index (2.00 ± 0.08 over the entire visible range) when naturally dried. By controlling the film thickness by using inkjet deposition, we produced images based on controlled interference and implementing color printing with one ink. The lack of dyes in the proposed method has good environmental prospects, because applied systems based on a crystalline anatase sol are nontoxic and biologically inert. The paper explains in detail the principle of producing interference images by the classical inkjet method and shows the advantages of this technique in depositing coatings with uniform thickness, which are required for large-scale interference color imaging even on unprepared polymer films. This article demonstrates the possibility of inkjet printing of nanostructures with a precision in thickness of up to 50 nm, we believe that the proposed approach will be the groundwork for developing interference color printing approach and allow to implement new methods of forming optical nano-objects by widely available techniques.

9.
Chem Commun (Camb) ; 51(100): 17764-7, 2015 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-26498200

RESUMO

Herein, we report a new method for the crystal growth of two Zn-based MOFs at room temperature (known MOF-5 and a new modification of [{Zn2(TBAPy)(H2O)2}·3.5DEF]n (1)) by employing slow diffusion conditions. Employing both Zn-based MOFs with different pore morphology made it possible to discover an anomalous adsorption of L-histidine in of up to 24.3 × 10(15) molecules cm(-2) at 25 °C. This is one of the first reports aimed not only at describing a new method for the targeted formation of crystalline MOFs and coordination polymers, but also at demonstrating the use of Zn-based MOFs as potential drug delivery materials, with highly effective adsorption of l-histidine given herein as an example.

10.
Chem Commun (Camb) ; 50(71): 10210-3, 2014 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-24835675

RESUMO

A single-step hydrothermal synthesis of a TiO2-Mil-125 composite was applied for the first time to produce a depleted perovskite/TiO2-MOF heterojunction solar cell with 6.4% power conversion efficiency (PCE), characterized by durable stability in air.


Assuntos
Energia Solar , Titânio/química
11.
Phys Chem Chem Phys ; 16(22): 10614-9, 2014 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-24752640

RESUMO

This paper reports an original technique that provides a highly pure crystalline sol of titania with controllable particle size by ultrasonic activation of the hydrolysis products of titanium isopropoxide in an aqueous medium at a near-neutral pH, which is potentially promising in impurity-sensitive electronics and biochemical engineering. Optimal conditions (H2O/TIP ratio, sonication time, etc.) for preparation of stable nanocrystalline titania sol were adopted. A new mechanism of regulation of aggregation and polycondensation under ultrasonic irradiation is proposed. Entrapment of human serum albumin (HSA) in the formed porous titania matrix results in high thermal stability of the protein dopants: the denaturation temperature of HSA is shifted by 31 °C.


Assuntos
Géis/síntese química , Nanoestruturas/química , Titânio/química , Géis/química , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Propriedades de Superfície , Temperatura , Água/química
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