scholarly journals Exploring the Assembly of Resorc[4]arenes for the Construction of Supramolecular Nano-Aggregates

2021 ◽  
Vol 22 (21) ◽  
pp. 11785
Author(s):  
Fabio Buonsenso ◽  
Francesca Ghirga ◽  
Isabella Romeo ◽  
Gabriella Siani ◽  
Serena Pilato ◽  
...  
Keyword(s):  
Water Solubility ◽  
Water Solution ◽  
Aqueous Media ◽  
Supramolecular Assembly ◽  
Biologically Active ◽  
Acid Dissociation ◽  
Hydroxyl Groups ◽  
Ph Values ◽  
Cyclic Oligomers ◽  
Upper Rim

Many biologically active compounds feature low solubility in aqueous media and, thus, poor bioavailability. The formation of the host-guest complex by using calixarene-based macrocycles (i.e., resorcinol-derived cyclic oligomers) with a good solubility profile can improve solubilization of hydrophobic drugs. Herein, we explore the ability of resorc[4]arenes to self-assemble in polar solutions, to form supramolecular aggregates, and to promote water-solubility of an isoflavone endowed with anti-cancer activity, namely Glabrescione B (GlaB). Accordingly, we synthesized several architectures featuring a different pattern of substitution on the upper rim including functional groups able to undergo acid dissociation (i.e., carboxyl and hydroxyl groups). The aggregation phenomenon of the amphiphilic resorc[4]arenes has been investigated in a THF/water solution by UV–visible spectroscopy, at different pH values. Based on their ionization properties, we demonstrated that the supramolecular assembly of resorc[4]arene-based systems can be modulated at given pH values, and thus promoting the solubility of GlaB.

Dissociation of imino proton(s) of a highly water-soluble metal-free phthalocyanine and determination of its pKa value in water

2013 ◽  
Vol 17 (06n07) ◽  
pp. 447-453 ◽  
Author(s):  
Hiroaki Isago ◽  
Harumi Fujita
Keyword(s):  
Aqueous Media ◽  
Thermal Reaction ◽  
Water Soluble ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Metal Free ◽  
Imino Proton ◽  
Pka Value ◽  
Triton X

Dissociation of imino proton(s) in the cavity of the macrocycle of a highly water-soluble, metal-free phthalocyanine ( H 2( H 4 tsppc ); where H 4 tsppc denotes tetrakis{(2′,6′-dimethyl-4′-sulfonic acid)phenoxy}phthalocyaninate) in ethanolic and aqueous solutions has spectrophotometrically been investigated. The spectral changes associated with reaction with NaOH have been found to involve one-proton transfer process in aqueous media while two-protons process in ethanolic media. The acid-dissociation constant of the first imino proton in water (in the presence of Triton X-100) has been determined to be 12.5 ± 0.2 (as pKa) at 25 °C. The doubly deprotonated species in EtOH has been easily converted to its corresponding cobalt(II) derivative by thermal reaction with anhydrous CoCl 2.

scholarly journals Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Modification ◽  
Structural Modification ◽  
Aqueous Media ◽  
Cross Linking ◽  
Ph Values ◽  
Acid Aqueous Solution ◽  
Reaction Media ◽  
Double Cross

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.

Artificial light-harvesting systems based on macrocycles-assisted supramolecular assembly in aqueous media

2021 ◽  
Author(s):  
Kaiya Wang ◽  
Krishnasamy Velmurugan ◽  
Bin Li ◽  
Xiao-Yu Hu
Keyword(s):  
Light Harvesting ◽  
Aqueous Media ◽  
Supramolecular Assembly ◽  
Routine Activities ◽  
Chemical Energy ◽  
Artificial Light ◽  
Natural Systems ◽  
Harvesting Systems

Light-harvesting, which converts sunlight into chemical energy by natural systems such as plants, bacteria, is one of the most universal routine activities in nature. So far, various artificial light-harvesting systems...

Phospholipid-containing films for improved drug release

2021 ◽  
pp. 30-33
Author(s):  
Jiahao Huang ◽  
◽  
Shawn Wettig
Keyword(s):  
Water Solubility ◽  
Aqueous Media ◽  
Active Pharmaceutical Ingredients ◽  
Natural Sources ◽  
Pharmaceutical Ingredients ◽  
Alternative Approach ◽  
Poor Water Solubility ◽  
Dissolution Efficiency ◽  
Oral Films ◽  
Liquid Liquid Phase Separation

Phospholipids from natural sources can delay liquid-liquid phase separation and improve supersaturation for active pharmaceutical ingredients with poor water-solubility in aqueous media. Researchers have developed oral films containing phospholipids to enhance the dissolution efficiency of hydrophobic pharmaceutical ingredients. Phospholipid-based oral films provide an alternative approach for compounding pharmacies to formulate drugs with poor water solubility.

Synthesis of water-soluble conducting polypyrrole with transition-metal tetrasulfonated porphyrins

2010 ◽  
Vol 14 (02) ◽  
pp. 128-132 ◽  
Author(s):  
Mohammad Reza Nabid ◽  
Mitra Shamsianpour ◽  
Roya Sedghi ◽  
Samira Osati ◽  
Nasser Safari
Keyword(s):  
Transition Metal ◽  
Water Solubility ◽  
Water Soluble ◽  
Sulfonated Polystyrene ◽  
Salting Out ◽  
Electrically Conducting ◽  
Ph Values ◽  
Ft Ir ◽  
A Charge ◽  
Conducting Polypyrrole

A novel catalytic route for the synthesis of a water-soluble and electrically conducting polypyrrole (PPy) in the presence of sulfonated polystyrene (SPS) is presented. Anionic water-soluble transition-metal tetrasulfonated porphyrins (TSPP) were used to catalyze the polymerization. The reactions were carried out with different monomer, catalyst, template and initiator concentrations and the optimum conditions are reported. Also various pH values ranging from 1 to 4 were investigated. The absorbance of the polaron bands at different pH values demonstrates that pH 2 is the best condition for polymerization. Precipitation or "salting out" phenomenon was highly dependent on the mentioned factors. The formation of PPy was confirmed by UV-vis and FT-IR spectroscopy. Cyclic voltammetry (CV) showed that the synthesized polymer has convenient electroactivity. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.

scholarly journals Effects of Chemical Post-treatments on Structural and Physicochemical Properties of Silk Fibroin Films Obtained From Silk Fibrous Waste

2020 ◽  
Vol 8 ◽  
Author(s):  
Melissa Puerta ◽  
Maria S. Peresin ◽  
Adriana Restrepo-Osorio
Keyword(s):  
Thermal Stability ◽  
Silk Fibroin ◽  
Water Solubility ◽  
Aqueous Media ◽  
Post Treatment ◽  
Water Soluble ◽  
Added Value ◽  
Degree Of Crystallinity ◽  
Crystalline Structures ◽  
Amorphous Structures

Silk fibroin (SF) is a protein polymer claimed to have outstanding potential for medical applications. However, because of the manufacturing process, materials from regenerated SF exhibit a higher percentage of amorphous structures. The amorphous structures cause the material to be water soluble and can significantly limit its applications in wet biological environments. In order to increase the amount of crystalline structures and decrease the water solubility of SF materials, post-treatment with alcohols is usually employed. SF can be obtained from silk fibrous wastes (SFW), usually discarded in silk textile processes. This represents an opportunity to produce materials with high added value from low-cost natural sources. In this study, SF was obtained from SFW, and films were made thereof followed by a post-treatment by immersion or in a saturated atmosphere of methanol (MeOH) or ethanol (EtOH), using different exposure times. The resulting films were analyzed according to crystallinity, the percentage of crystalline and amorphous structures, and thermal stability. Also, water absorption and weight loss in aqueous media were determined. The results showed a significant increase in crystalline structures in all treated samples, varying according to the type and time of exposure to post-treatment conducted. The highest increase was shown in the case of the post-treatment by immersion in MeOH for 1 h, with a 23% increase over the untreated sample. This increase in crystallinity was reflected in an increase in the degradation temperature and a degradation rate of 5.3% on day 7. The possibility of tuning the degree of crystallinity, as well as thermal stability and aqueous integrity of thin films of SFW, can be applied to adjust these materials to the requirements of specific biomedical applications.

scholarly journals POSSIBILITIES OF THE USE OF ELECTROLYZED WATER IN POULTRY BREEDING

2013 ◽  
Vol 17 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Dana Jirotková ◽  
Miloslav Šoch ◽  
Naděžda Kernerová ◽  
Václav Pálka ◽  
Luboš Zábranský ◽  
...  
Keyword(s):  
Water Loss ◽  
Water Solution ◽  
T Test ◽  
Feed Water ◽  
Alternative Procedure ◽  
Ph Values ◽  
Poultry Breeding ◽  
Number Of Microorganisms ◽  
Pse Meat ◽  
The Individual

Abstract the paper deals with verification of the effects of the electrolyzed NaCl-water solution where a new possibility for an alternative procedure to disinfect water is provided. The experiment was done in two chicken breeding halls where the solution was used to disinfect the stable premises and at the same time it was applied into the feed water. The effects of disinfection were verified directly in the stable premises at the interval of 20, 40, 60 minutes after application. Staphylococci and Streptococci and Enterococci were inactive always after 60 minutes of effect. There was significant decrease in the number of total number of microorganisms. An evaluation of the qualitative features of the produced chicken meat, focused mainly on the PSE meat disorder, was a part of the examination, too. After the research was finished, the chickens were slaughtered at the industrial slaughterhouse and samples of the meat were taken (gradually 157 pieces in total) from the individual halls and analysed. The determined share in water loss by dripping was the most significant of the monitored indicators, which could suggest a possible development of the PSE problem, however, the meat colour and the pH values did not confirmed this. The values of pH, colour and loss of water (dripping) ascertained, processed by the T-test did not confirm the hypothesis of the assumed possible differences in occurrence of critical values of these indicators in both groups observed.

Chromatographic Determination of Thermodynamic Acid Dissociation Constants of Tetracycline Antibiotics and Their Epimers

2019 ◽  
Vol 57 (8) ◽  
pp. 745-750
Author(s):  
İlkay Konçe ◽  
Ebru Çubuk Demiralay ◽  
Hülya Yılmaz Ortak
Keyword(s):  
Experimental Data ◽  
Dissociation Constant ◽  
Binary Mixtures ◽  
Dissociation Constants ◽  
Reversed Phase ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Chromatography Method ◽  
Ph Values

Abstract The presented study describes the development of reversed-phase liquid chromatography method using a core-shell particle column with a pentafluorophenyl stationary phase for the dissociation constant (pKa) determination of the tetracycline group antibiotics (tetracycline, oxytetracycline, chlortetracycline) and their epimers (4-epitetracycline, 4-epioxytetracycline, 4-epichlortetracycline). The pH values were measured in the acetonitrile (ACN)–water binary mixtures, used as mobile phases, instead of in water and take into account the effect of the activity coefficients. Thermodynamic acid dissociation constant (pKa1) values of studied antibiotics and their epimers were calculated using retention factor (k) at different mobile phase pH values in studied binary mixtures with ACN percentages of 20, 25, 30 and 35% (v/v). Experimental data were analyzed by using an Origin 7.0 program to fit experimental data to the nonlinear expression derived. From calculated pKa1 values, the aqueous pKa values of studied compounds were calculated by different approaches and these values were compared.

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