scholarly journals New Materials Based on Cationic Porphyrins Conjugated to Chitosan or Titanium Dioxide: Synthesis, Characterization and Antimicrobial Efficacy

2019 ◽  
Vol 20 (10) ◽  
pp. 2522 ◽  
Author(s):  
Kelly A. D. F. Castro ◽  
Nuno M. M. Moura ◽  
Flávio Figueira ◽  
Rosalina I. Ferreira ◽  
Mário M. Q. Simões ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photophysical Properties ◽  
Antimicrobial Photodynamic Therapy ◽  
New Materials ◽  
Solid Supports ◽  
Cationic Porphyrins ◽  
E Coli ◽  
Porphyrin Core ◽  
Post Functionalization

The post-functionalization of 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide, known as a highly efficient photosensitizer (PS) for antimicrobial photodynamic therapy (aPDT), in the presence of 3- or 4-mercaptobenzoic acid, afforded two new tricationic porphyrins with adequate carboxylic pending groups to be immobilized on chitosan or titanium oxide. The structural characterization of the newly obtained materials confirmed the success of the porphyrin immobilization on the solid supports. The photophysical properties and the antimicrobial photodynamic efficacy of the non-immobilized porphyrins and of the new conjugates were evaluated. The results showed that the position of the carboxyl group in the mercapto units or the absence of these substituents in the porphyrin core could modulate the action of the photosensitizer towards the bioluminescent Gram-negative Escherichia coli bacterium. The antimicrobial activity was also influenced by the interaction between the photosensitizer and the type of support (chitosan or titanium dioxide). The new cationic porphyrins and some of the materials were shown to be very stable in PBS and effective in the photoinactivation of E. coli bacterium. The physicochemical properties of TiO2 allowed the interaction of the PS with its surface, increasing the absorption profile of TiO2, which enables the use of visible light, inactivating the bacteria more efficiently than the corresponding PS immobilized on chitosan.

scholarly journals Reductive Amination Reaction for the Functionalization of Cellulose Nanocrystals

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5032
Author(s):  
Omar Hassan Hassan Omar ◽  
Rosa Giannelli ◽  
Erica Colaprico ◽  
Laura Capodieci ◽  
Francesco Babudri ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Reductive Amination ◽  
Photophysical Properties ◽  
New Materials ◽  
Light Emitting ◽  
Emission Profile ◽  
Organic Light ◽  
Amination Reaction ◽  
Functionalized Materials

Cellulose nanocrystals (CNCs) represent intriguing biopolymeric nanocrystalline materials, that are biocompatible, sustainable and renewable, can be chemically functionalized and are endowed with exceptional mechanical properties. Recently, studies have been performed to prepare CNCs with extraordinary photophysical properties, also by means of their functionalization with organic light-emitting fluorophores. In this paper, we used the reductive amination reaction to chemically bind 4-(1-pyrenyl)butanamine selectively to the reducing termini of sulfated or neutral CNCs (S_CNC and N_CNC) obtained from sulfuric acid or hydrochloric acid hydrolysis. The functionalization reaction is simple and straightforward, and it induces the appearance of the typical pyrene emission profile in the functionalized materials. After a characterization of the new materials performed by ATR-FTIR and fluorescence spectroscopies, we demonstrate luminescence quenching of the decorated N_CNC by copper (II) sulfate, hypothesizing for these new functionalized materials an application in water purification technologies.

Characterization of Waste from the Production of Titanium Dioxide (UOW) for Reuse in Other Processes

2021 ◽  
Vol 47 (3) ◽  
pp. 590-600
Author(s):  
José da Silva Andrade Neto ◽  
Nilson Santana de Amorim Júnior ◽  
Vitor Souza Santos ◽  
Bruna Bueno Mariani ◽  
Diana Dayse Mariano de Albuquerque ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Environmental Issues ◽  
Ceramic Materials ◽  
Raw Material ◽  
Industrial Processes ◽  
New Materials ◽  
Physical Chemical ◽  
Expected Performance ◽  
Starting Point

The reuse of waste generated in several industrial processes through the development of new materials for civil construction has been shown to be a viable alternative to meet environmental issues. New products can be developed that satisfy the expected performance and durability requirements while including this material. The main starting point for the development of projects that seek the safe use of these wastes is an extensive characterization. Unreacted Ore Waste (UOW), a waste generated during the production of titanium dioxide (TiO2), was characterized in terms of its physical, chemical, mineralogical, environmental, and radiological, as well as thermal properties. There is currently no effective reuse plan for UOW and it is disposed of in industrial landfills. From the characterization, possible routes for using UOW are identified, such as its addition to mortars with photocatalytic potential, and its use as a raw material in the production of Portland cement and ceramic materials.

Synthesis and Spectroscopic Characterization of Meso-tetra (3-hydroxyphenyl) Porphyrin

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Carmen Cretu ◽  
Carmen Bucovicean ◽  
Ileana Armeanu ◽  
Ana-Maria Lacrama ◽  
Eugenia Fagadar-Cosma
Keyword(s):  
Photophysical Properties ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
New Materials ◽  
Large Excess ◽  
Excitation Spectra ◽  
Propionic Anhydride ◽  
Ft Ir ◽  
Meso Position

The preparation of compounds where functionality in the meso-position of the tetrapyrrolic ring is introduced during the formation of the porphyrin represents the main purpose of this work. The synthesis of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (3-OHPP), by Adler method, implying reaction between m-hydroxybenzaldehyde/ pyrrole/ propionic anhydride at a molar ratio of 1/ 1/ 1, in large excess of propionic acid, as solvent, is presented. The hydroxy-porphyrin was isolated from the reaction mixture by precipitation with hexane and it was purified by column chromatography. The purity of the compound (3-OHPP) was certified by HPLC on polar KROMASIL SI 100 column, using as eluent hexane. The structure was elucidated by 1H-NMR, FT-IR, fluorescence and UV-vis analysis. Photophysical properties were studied by UV-vis, emission and excitation spectra performed in different solvents and in various acid pH-media. The obtained compound represents a precursor for new materials exhibiting opto-electronic properties, useful in PDT therapy and for further applications in solar energy conversion and catalysis.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Antimicrobial Resistance and Virulence Characterization of E. Coli Isolated from Subclinical Mastitic Sheep and Goats

2018 ◽  
Vol 34 (3) ◽  
pp. 267-278
Author(s):  
Ashraf A. Abd El-Tawab ◽  
Mohamed G. Aggour ◽  
Fatma I. El- Hofy ◽  
Marwa M. Y. El- Mesalami
Keyword(s):  
Antimicrobial Resistance ◽  
Sheep And Goats ◽  
E Coli

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

scholarly journals Molecular characterization of clinical carbapenem-resistant Enterobacterales from Qatar

2021 ◽  
Author(s):  
Fatma Ben Abid ◽  
Clement K. M. Tsui ◽  
Yohei Doi ◽  
Anand Deshmukh ◽  
Christi L. McElheny ◽  
...  
Keyword(s):  
Common Species ◽  
Clinical Samples ◽  
Whole Genome ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Genes Encoding ◽  
Encoding Genes ◽  
Sequence Types ◽  
Common Sequence

AbstractOne hundred forty-nine carbapenem-resistant Enterobacterales from clinical samples obtained between April 2014 and November 2017 were subjected to whole genome sequencing and multi-locus sequence typing. Klebsiella pneumoniae (81, 54.4%) and Escherichia coli (38, 25.5%) were the most common species. Genes encoding metallo-β-lactamases were detected in 68 (45.8%) isolates, and OXA-48-like enzymes in 60 (40.3%). blaNDM-1 (45; 30.2%) and blaOXA-48 (29; 19.5%) were the most frequent. KPC-encoding genes were identified in 5 (3.6%) isolates. Most common sequence types were E. coli ST410 (8; 21.1%) and ST38 (7; 18.4%), and K. pneumoniae ST147 (13; 16%) and ST231 (7; 8.6%).

scholarly journals Synthesis and Characterization of a Bioconjugate Based on Oleic Acid and L-Cysteine

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1791
Author(s):  
Marco Vizcarra-Pacheco ◽  
María Ley-Flores ◽  
Ana Mizrahim Matrecitos-Burruel ◽  
Ricardo López-Esparza ◽  
Daniel Fernández-Quiroz ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Materials Science ◽  
Critical Micellar Concentration ◽  
Synthesis And Characterization ◽  
New Materials ◽  
Visible Spectroscopy ◽  
Amide Bonds ◽  
Transmission Electron ◽  
Self Assembled

One of the main challenges facing materials science today is the synthesis of new biodegradable and biocompatible materials capable of improving existing ones. This work focused on the synthesis of new biomaterials from the bioconjugation of oleic acid with L-cysteine using carbodiimide. The resulting reaction leads to amide bonds between the carboxylic acid of oleic acid and the primary amine of L-cysteine. The formation of the bioconjugate was corroborated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and nuclear magnetic resonance (NMR). In these techniques, the development of new materials with marked differences with the precursors was confirmed. Furthermore, NMR has elucidated a surfactant structure, with a hydrophilic part and a hydrophobic section. Ultraviolet-visible spectroscopy (UV-Vis) was used to determine the critical micellar concentration (CMC) of the bioconjugate. Subsequently, light diffraction (DLS) was used to analyze the size of the resulting self-assembled structures. Finally, transmission electron microscopy (TEM) was obtained, where the shape and size of the self-assembled structures were appreciated.

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