ionic complexation
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2022 ◽  
Author(s):  
María Florencia Sanchez ◽  
María Laura Guzman ◽  
Jesica Flores-Martín ◽  
Mariano Cruz Del Puerto ◽  
Carlos Laino ◽  
...  

Abstract The development of new treatments capable of controlling infections and pain related to burns continues to be a challenge. Antimicrobials are necessary tools, but these can be cytotoxic for regenerating cells.In this study, antibiotic-anesthetic smart systems obtained by ionic complexation of polyelectrolytes with ciprofloxacin and lidocaine were obtained as film and hydrogel. The complexation of ciprofloxacin with natural polyelectrolytes efficiently contributed to increasing biocompatibility in a primary culture of isolated fibroblasts. In addition, the relative levels of the proteins integrin β1 and p-FAK involved in cell migration were increased with no modifications in cell mobility. Their evaluation in a deep second-degree burn model revealed fast reepithelization, with appendage conservation and complete dermis organization. Encouragingly, we found that both the film and the hydrogel showed a significantly superior performance compared to the reference treatment of silver sulfadiazine cream. This work highlights the great potential of this smart system as an attractive dressing for burns, which surpasses currently available treatments.


Gels ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 6
Author(s):  
Hiroyuki Takeno ◽  
Nagisa Suto

We investigated the mechanical and structural properties of composite hydrogels composed of chitosan nanofiber (ChsNF), positively charged alumina-coated silica (ac-SiO2) nanoparticles, carboxylated poly (vinyl alcohol) (cPVA), and borax. ChsNF/cPVA/borax hydrogels without ac-SiO2 exhibited high Young’s modulus but poor elongation, whereas cPVA/ac-SiO2/borax hydrogels without ChsNF had moderate Young’s modulus but high elongation. ChsNF/ac-SiO2/cPVA/borax hydrogels using both ChsNF and ac-SiO2 as reinforcement agents exhibited high extensibility (930%) and high Young′s modulus beyond 1 MPa at a high ac-SiO2 concentration. The network was formed by multiple crosslinking such as the complexation between borate and cPVA, the ionic complexation between ac-SiO2 and cPVA, and the hydrogen bond between ChsNF and cPVA. Structural analysis by synchrotron small-angle X-ray scattering revealed that the nanostructural inhomogeneity in ChsNF/ac-SiO2/cPVA/borax hydrogel was suppressed compared to those of the ChsNF/cPVA/borax and cPVA/ac-SiO2/borax hydrogels.


Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3098
Author(s):  
Maialen Argaiz ◽  
Fernando Ruipérez ◽  
Miren Aguirre ◽  
Radmila Tomovska

The performance of waterborne (meth)acrylic coatings is critically affected by the film formation process, in which the individual polymer particles must join to form a continuous film. Consequently, the waterborne polymers present lower performance than their solvent-borne counter-polymers. To decrease this effect, in this work, ionic complexation between oppositely charged polymer particles was introduced and its effect on the performance of waterborne polymer films was studied. The (meth)acrylic particles were charged by the addition of a small amount of ionic monomers, such as sodium styrene sulfonate and 2-(dimethylamino)ethyl methacrylate. Density functional theory calculations showed that the interaction between the selected main charges of the respective functional monomers (sulfonate–amine) is favored against the interactions with their counter ions (sulfonate–Na and amine–H). To induce ionic complexation, the oppositely charged latexes were blended, either based on the same number of charges or the same number of particles. The performance of the ionic complexed coatings was determined by means of tensile tests and water uptake measurements. The ionic complexed films were compared with reference films obtained at pH at which the cationic charges were in neutral form. The mechanical resistance was raised slightly by ionic bonding between particles, producing much more flexible films, whereas the water penetration within the polymeric films was considerably hindered. By exploring the process of polymer chains interdiffusion using Fluorescence Resonance Energy Transfer (FRET) analysis, it was found that the ionic complexation was established between the particles, which reduced significantly the interdiffusion process of polymer chains. The presented ionic complexes of sulfonate–amine functionalized particles open a promising approach for reinforcing waterborne coatings.


Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 80
Author(s):  
Joseph M. Scalet ◽  
Tiffany C. Suekama ◽  
Jeayoung Jeong ◽  
Stevin H. Gehrke

Tough hydrogels were made by hydrolysis of a neutral interpenetrating network (IPN) of poly (N-vinyl formamide) PNVF and polyacrylamide (PAAm) networks to form an IPN of polyvinylamine (PVAm) and poly (acrylic acid) (PAAc) capable of intermolecular ionic complexation. Single network (SN) PAAm and SN PNVF have similar chemical structures, parameters and physical properties. The hypothesis was that starting with neutral IPN networks of isomeric monomers that hydrolyze to comparable extents under similar conditions would lead to formation of networks with minimal phase separation and maximize potential for charge–charge interactions of the networks. Sequential IPNs of both PNVF/PAAm and PAAm/PNVF were synthesized and were optically transparent, an indication of homogeneity at submicron length scales. Both IPNs were hydrolyzed in base to form PVAm/PAAc and PAAc/PVAm IPNs. These underwent ~5-fold or greater decrease in swelling at intermediate pH values (3–6), consistent with the hypothesis of intermolecular charge complexation, and as hypothesized, the globally neutral, charge-complexed gel states showed substantial increases in failure properties upon compression, including an order of magnitude increases in toughness when compared to their unhydrolyzed states or the swollen states at high or low pH values. There was no loss of mechanical performance upon repeated compression over 95% strain.


Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 19
Author(s):  
Anjali Sharma ◽  
Marek Bekir ◽  
Nino Lomadze ◽  
Svetlana Santer

Ionic complexation of azobenzene-containing surfactants with any type of oppositely charged soft objects allows for making them photo-responsive in terms of their size, shape and surface energy. Investigation of the photo-isomerization kinetic and isomer composition at a photo-stationary state of the photo-sensitive surfactant conjugated with charged objects is a necessary prerequisite for understanding the structural response of photo-sensitive complexes. Here, we report on photo-isomerization kinetics of a photo-sensitive surfactant in the presence of poly(acrylic acid, sodium salt). We show that the photo-isomerization of the azobenzene-containing cationic surfactant is slower in a polymer complex compared to being purely dissolved in aqueous solution. In a photo-stationary state, the ratio between the trans and cis isomers is shifted to a higher trans-isomer concentration for all irradiation wavelengths. This is explained by the formation of surfactant aggregates near the polyelectrolyte chains at concentrations much lower than the bulk critical micelle concentration and inhibition of the photo-isomerization kinetics due to steric hindrance within the densely packed aggregates.


2020 ◽  
Vol 567 ◽  
pp. 419-428
Author(s):  
Jiaqi Yan ◽  
Shaoyi Yan ◽  
Joseph C. Tilly ◽  
Yeongun Ko ◽  
Byeongdu Lee ◽  
...  

Author(s):  
Vinu V Nair ◽  
Rajesh Asija ◽  
A Gupta

Introduction: Neem (Azadirachta indica, Meliaceae) is being used as an antimicrobial agent in traditional systems of medicines since ancient times. Neem is also applied on wounds in the form of aqueous extracts of various parts of the plant but is associated with problems of stability on long term storage. Objective: In the present work, the aim was to incorporate Neem (Azadirachta indica) extract in hydrogel system and prepare microbeads for application on wounds. Material and methods: The microbeads were prepared by mixing of drug and polymers to cause poly ionic complexation. The formulation was evaluated for various pharmaceutical parameters such as Solubility, Drug Release, Water Holding Capacity, % Drug Entrapped, Bead Diameter Measurement and Antimicrobial study. Result and Discussion: The evaluation of the optimized batch showed % drug entrapped to be 5.61 %, drug release of 65.688% in phosphate buffer pH 8 within 5 hrs and water uptake of 80% which were similar to the solutions obtained by the design expert DX7 Statease software. This suggested that the optimization model is validated. The microbeads of the optimized batch had a diameter of approximately 80 μm. Conclusion: Polymeric encapsulation in the form of beads allowed controlled delivery as well as enhanced stability of Azadirachtin. It provides a cost-effective antimicrobial therapy.


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