Structure Of Aqueous Systems Research Articles

NMR studies of self-organization behavior of hydrophobically functionalized poly(4-styrenosulfonic-co-maleic acid) in aqueous solution

Specially designed hydrophobically functionalized polyelectrolytes (HF-PEs) provide an important area of study, their unique properties being similar to those of biological systems, among them the strong tendency toward self-organization in aqueous solution caused by a combination of electrostatic and hydrophobic forces. A significant issue in this context is the comprehensive physicochemical characterization of adsorption and aggregation properties of these amphiphilic polyelectrolytes. The main aim of the present research has been to synthesize and study aggregation properties in an aqueous solution of the hydrophobically functionalized poly(4-styrenosulfonic-co-maleic acid) (PSS/MA) with a differing degree of hydrophobization, side-chain lengths and pH-labile moiety type (i.e., ester (PSS/MA-g-CnOH) or secondary amide (PSS/MA-g-CnNH2) groupings). Comprehensive analysis of self-assembly properties, including utilization of high-resolution NMR techniques (diffusion-ordered and nuclear Overhauser effect spectroscopies, T1 and T2 relaxometry) and dynamic light scattering, revealed a strong dependence on concentration and type of labile linking group (ester or amide). It has been noticed that more rigid amide bonds hinder the formation of highly organized structures in aqueous systems compared to polyelectrolytes with ester moieties. Our results were supported by molecular modeling. The performed studies enabled us to obtain crucial information about the hydrophobized PEs structure and its influence on aggregation properties that are crucial for their application in pH-sensitive nanosized thin films and nanocarriers.

Selecting temperature-dependent variables in near-infrared spectra for aquaphotomics

Temperature-dependent near-infrared (NIR) spectroscopy has been developed and taken as a new technique for aquaphotomic studies to analyze water structures in aqueous systems. However, due to the overlapping, it is difficult to obtain the information from the spectra to understand the temperature dependency. In this work, a method was proposed for selection of the temperature-dependent variables (wavenumbers) from the NIR spectra measured at different temperature. Continuous wavelet transform (CWT) was used to decompose the spectra into the spectral components with different frequencies, and then Monte-Carlo uninformative variable elimination (MC-UVE) was employed to evaluate the dependency of the variables with temperature. The feasibility of the method was tested by simulated datasets and the applicability was proved by the temperature-dependent NIR spectra of water and aqueous solutions. Several variables were selected from the spectra of water, indicating the complexity of water structure. The variables are located at similar but not identical wavenumbers for different solutions and they have a good relationship with the concentration of the solute, demonstrating that water spectrum can be a mirror to reflect the difference of the aqueous solutions. The method may provide a tool to identify the characteristic variables in NIR spectra for understanding the function of water in aqueous systems.

Liposomal systems as carriers for bioactive compounds.

Since the revolutionary discovery that phospholipids can form closed bilayered structures in aqueous systems, the study of liposomes has become a very interesting area of research. The versatility and amazing biocompatibility of liposomes has resulted in their wide-spread use in many scientific fields, and many of their applications, especially in medicine, have yielded breakthroughs in recent decades. Specifically, their easy preparation and various structural aspects have given rise to broadly usable methodologies to internalize different compounds, with either lipophilic or hydrophilic properties. The study of compounds with potential biotechnological application(s) is generally related to evaluation and risk assessment of the possible cytotoxic or therapeutic effects of the compound under study. In most cases, undesirable side-effects are associated with an interaction of the liposome with the cell membrane and/or its absorption and subsequent interaction with a cellular biomolecule. Liposomal carrier systems have an unprecedented potential for delivering bioactive substances to specific molecular targets due to their biocompatibility, biodegradability and low toxicity. Liposomes are therefore considered to be an invaluable asset in applied biotechnology studies due to their potential for interaction with both hydrophilic and lipophilic compounds.

Liposomes: versatile and biocompatible nanovesicles for efficient biomolecules delivery.

Since the revolutionary discovery that phospholipids can form closed bilayered structures in aqueous systems, liposomes have become a very interesting topic of research. Because of their versatility and amazing biocompatibility, the use of liposomes has been widely accepted in many scientific disciplines. Their applications, especially in medicine, have yielded breakthroughs with anticancer-drug carriers over the past few decades. Specifically, their easy preparation and various structural aspects have given rise to a broadly usable way to internalize biomolecules such as drugs, DNA, RNA and even imaging probes. This review article reports recent developments in liposomal drug delivery and gene delivery, and thoroughly covers the synthesis and different kinds of liposomal surface modification techniques that have resulted in higher stability and efficiency with respect to the use of liposomes in tumor cell targeting, site-specific release, and extending blood retention times.

Fluorocarbon surfactants. Phase equilibriums and phase structures in aqueous systems of a totally fluorinated fatty acid and some of its salts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFluorocarbon surfactants. Phase equilibriums and phase structures in aqueous systems of a totally fluorinated fatty acid and some of its saltsKrister Fontell and Bjoern LindmanCite this: J. Phys. Chem. 1983, 87, 17, 3289–3297Publication Date (Print):August 1, 1983Publication History Published online1 May 2002Published inissue 1 August 1983https://doi.org/10.1021/j100240a023RIGHTS & PERMISSIONSArticle Views269Altmetric-Citations76LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts