Interpolyelectrolyte Complexes Research Articles

Preparation of Antimicrobial Agents: From Interpolyelectrolyte Complexes to Silver-Containing Metal–Polymer Complexes and Nanocomposites

In order to control pathogenic microorganisms, three polymer compositions were prepared and tested. First, a water-soluble positively charged polycomplex was synthesized via the electrostatic binding of anionic polyacrylic acid to an excess of polyethylenimine to enhance the biocidal activity of the polycation. Second, an aqueous solution of AgNO3 was added to the polycomplex, thus forming a ternary polycation-polyanion-Ag1+ complex with an additional antimicrobial effect. Third, the resulting ternary complex was subjected to UV irradiation, which ensured the conversion of Ag1+ ions into Ag nanoparticles ranging in size mainly from 10 to 20 nm. Aqueous solutions of the polymer compositions were added to suspensions of the Gram-positive bacteria S. aureus and the Gram-negative bacteria P. aeruginosa, with the following main results: (a) Upon the addition of the binary polycomplex, 30% or more of the cells survived after 20 h. (b) The ternary complex killed S. aureus bacteria but was ineffective against P. aeruginosa bacteria. (c) When the ternary complex with Ag nanoparticles was added, the percentage of surviving cells of both types did not exceed 0.03%. The obtained results are valuable for the development of antibacterial formulations.

SYNTHESIS AND PROPERTIES OF BINARY AND TERNARY INTERPOLYELECTROLYTE COMPLEXES OF CHITOSAN

This review provides a comprehensive summary of the results of research, published from 2002 to 2023, on the synthesis, physicochemical properties and medical applications of binary and ternary interpolyelectrolyte complexes (IPECs) based on chitosan, carboxymethylcellulose and collagen. The application of IPECs in the medical field mainly refers to their use in medical therapy and bone regeneration. In addition, we describe our original studies on IPECs based on chitosan and collagen.

Polyion Hydrogels of Polymeric and Nanofibrous Carboxymethyl Cellulose and Chitosan: Mechanical Characteristics and Potential Use in Environmental Remediation.

Recently, cellulose and other biomass nanofibers (NFs) have been increasingly utilized in the design of sustainable materials for environmental, biomedical, and other applications. However, the past literature lacks a comparison of the macromolecular and nanofibrous states of biopolymers in various materials, and the advantages and limitations of using nanofibers (NF) instead of conventional polymers are poorly understood. To address this question, hydrogels based on interpolyelectrolyte complexes (IPECs) between carboxymethyl cellulose nanofibers (CMCNFs) and chitosan (CS) were prepared by ele+ctrostatic cross-linking and compared with the hydrogels of carboxymethyl cellulose (CMC) and CS biopolymers. The presence of the rigid CMCNF altered the mechanism of the IPEC assembly and drastically affected the structure of IPEC hydrogels. The swelling ratios of CMCNF-CS hydrogels of ca. 40% were notably lower than the ca. 100-300% swelling of CMC-CS hydrogels. The rheological measurements revealed a higher storage modulus (G') of the CMCNF-CS hydrogel, reaching 13.3 kPa compared to only 3.5 kPa measured for the CMC-CS hydrogel. Further comparison of the adsorption characteristics of the CMCNF-CS and CMC-CS hydrogels toward Cu2+, Cd2+, and Hg2+ ions showed the slightly higher adsorption capacity of CMC-CS for Cu2+ but similar adsorption capacities for Cd2+ and Hg2+. The adsorption kinetics obeyed the pseudo-second-order adsorption model in both cases. Overall, while the replacement of CMC with CMCNF in hydrogel does not significantly affect the performance of such systems as adsorbents, CMCNF imparts IPEC hydrogel with higher stiffness and a frequency-independent loss (G″) modulus and suppresses the hydrogel swelling, so can be beneficial in practical applications that require stable performance under various dynamic conditions.

Development of Interpolyelectrolyte Complex Based on Chitosan and Carboxymethylcellulose for Stabilizing Sandy Soil and Stimulating Vegetation of Scots Pine (Pinus sylvestris L.).

The issue of water and wind erosion of soil remains critically important. Polymeric materials offer a promising solution to this problem. In this study, we prepared and applied an interpolyelectrolyte complex (IPEC) composed of the biopolymers chitosan and sodium carboxymethyl cellulose (Na-CMC) for the structuring of forest sandy soils and the enhancement of the pre-sowing treatment of Scots pine (Pinus sylvestris L.) seeds. A nonstoichiometric IPEC [Chitosan]:[Na-CMC] = [3:7] was synthesized, and its composition was determined using gravimetry, turbidimetry, and rheoviscosimetry methods. Soil surface treatment with IPEC involved the sequential application of a chitosan polycation (0.006% w/w) and Na-CMC polyanion (0.02% w/w) relative to the air-dry soil weight. The prepared IPEC increased soil moisture by 77%, extended water retention time by sixfold, doubled the content of agronomically valuable soil fractions > 0.25 mm, enhanced soil resistance to water erosion by 64% and wind erosion by 81%, and improved the mechanical strength of the soil-polymer crust by 17.5 times. Additionally, IPEC application resulted in slight increases in the content of humus, mobile potassium, mobile phosphorus, ammonium nitrogen, and mineral salts in the soil while maintaining soil solution pH stability and significantly increasing nitrate nitrogen levels. The novel application technologies of biopolymers and IPEC led to a 16-25% improvement in Scots pine seed germination and seedling growth metrics.

Evidence for Morphology Control by Polyelectrolyte Templating in PEDT:PSSH

AbstractDespite decades of research, the fundamental question of structure and morphology of the poly(3,‐4‐ethylenedioxythiophene):poly(styrene sulfonate) complex (PEDT: PSS) electrically conducting polymer remains open. Here, through a systematic study of the polymerization of 3,4‐ethylenedioxythiophene (EDT) on two series of sulfonated polystyrenes, i.e., PS‐co‐SSH and PS‐co‐SSNa, with per cent sulfonation 24 ≲ x ≲ 100, this study shows that the substrate polyelectrolyte not only affords charge compensation and processability, but also templates the morphology of the growing PEDT chain—whether extended, coiled or collapsed. This determines the electrical, electronic and optical properties of the resultant PEDT: PSS interpolyelectrolyte complexes, including their work function. This study calls this the Polyelectrolyte Template model. The PEDT: PSS complex retains memory of its polymerization morphology even after subsequent ion‐exchange, for example, to the same acid form. Electrical conductivity decreases sharply with decreasing x, and depends on whether the polymerization is templated with the H+ or Na+ form of the polyelectrolyte. The work function is less sensitive to x, but exhibits a transition from low to high work function (5.2–5.3 eV) when x exceeds a threshold, which indicates formation of a polar surface driven by molecular‐scale segregation of the PSS counteranion. This surface segregation also affects the ability of these complexes to inject holes into very large‐ionization‐energy semiconductors.

Postmodification with Polycations Enhances Key Properties of Alginate-Based Multicomponent Microcapsules.

Postmodification of alginate-based microspheres with polyelectrolytes (PEs) is commonly used in the cell encapsulation field to control microsphere stability and permeability. However, little is known about how different applied PEs shape the microsphere morphology and properties, particularly in vivo. Here, we addressed this question using model multicomponent alginate-based microcapsules postmodified with PEs of different charge and structure. We found that the postmodification can enhance or impair the mechanical resistance and biocompatibility of microcapsules implanted into a mouse model, with polycations surprisingly providing the best results. Confocal Raman microscopy and confocal laser scanning microscopy (CLSM) analyses revealed stable interpolyelectrolyte complex layers within the parent microcapsule, hindering the access of higher molar weight PEs into the microcapsule core. All microcapsules showed negative surface zeta potential, indicating that the postmodification PEs get hidden within the microcapsule membrane, which agrees with CLSM data. Human whole blood assay revealed complex behavior of microcapsules regarding their inflammatory and coagulation potential. Importantly, most of the postmodification PEs, including polycations, were found to be benign toward the encapsulated model cells.

Design of Highly Porous Materials Based on Chitosan/Pectin Interpolyelectrolyte Complex for Wound Healing Application

Interpolyelectrolyte complexes (IPECs) of polysaccharides are multifunctional polymer materials that improve the mechanical and physicochemical properties of individual polysaccharides. In this study, highly porous (>90%) materials based on IPECs of versatile natural polysaccharides, chitosan (30 and 1,200 kDa) and pectin, are obtained by freeze-drying technique. To enhance the interaction between chitosan and pectin macromolecules, the latter are chemically functionalized with dialdehyde groups. The chitosan-/aldehyde-functionalized pectin (Chit/AF-Pect) polyelectrolyte complex sponges obtained are characterized using SEM, FTIR spectroscopy, and TGA. The swelling capacity study reveals a higher swelling ratio of IPEC sponges with an increase in both the molecular weight and content of chitosan: for Chit30/AF-Pect, the swelling ratio rises from 327% to 480%, while for Chit1200/AF-Pect, from 681% to 1,066%. Additionally, the in vitro degradation test demonstrates higher stability of Chit1200/AF-Pect sponges in comparison with those of Chit30/AF-Pect: after 4 days of incubation, the weight losses are found to be 9%–16% and 18%–41%, respectively. The cytotoxicity study shows that Chit30/AF-Pect sponges are noncytotoxic, with cell viability values >70%. Furthermore, the Chit30/AF-Pect sponges, obtained at chitosan:pectin weight ratio of 5:1, exhibit bactericidal activity against Escherichia coli BIM B-984 G, Pseudomonas aeruginosa BIM B-807 G, Staphylococcus aureus BIM B-1841, and slightly inhibit the growth of Enterococcus faecalis BIM B-1530 G. These findings indicate that the obtained Chit30/AF-Pect sponges can be used to create wound dressings for wound healing applications.

New Carriers for Bioadhesive Gastroretentive Drug Delivery Systems Based on Eudragit® EPO/Eudragit® L100 Interpolyelectrolyte Complexes

The aim of this study was the analysis of interpolyelectrolyte complexes (IPECs) based on Eudragit® EPO and Eudragit® L100 as prospective carriers for gastroretentive drug delivery systems (GRDDS) using two model drugs: metronidazole (MZ) and acyclovir (ACR). Eudragit® EPO/L100 IPECs with different pH concentrations were characterized by different degrees of swelling in mimicking fasted stomach medium (0.1 M HCl) and saved their shape for 6 h. The microenvironmental changes in IPEC structures in acidic medium were investigated using FT-IR spectroscopy, thermal and elemental analysis. IPEC samples showed bioadhesive properties that were not significantly different from the positive control (Carbopol) in the test with the mucin compacts. The release rate of metronidazole (class I BCS) from IPEC matrices increased with the increasing degree of swelling. IPEC 1 provided 49.62 ± 6.20% and IPEC 2 reached 87.69 ± 5.15% of metronidazole release after 6 h in mimicking fasted stomach medium (0.1 M HCl). The total amount of released acyclovir (class III BCS) from IPEC 1 was 25.76 ± 5.67% and from IPEC 2 was 21.48 ± 5.00%. Release of both drugs was controlled by relaxation of polymeric chains in matrices according to the Peppas–Sahlin model. According to the received results, investigated interpolymer complexes are prospects for further evaluation as carriers for gastroretentive bioadhesive systems.

Exciton Transfer Between Extended Electronic States in Conjugated Inter-Polyelectrolyte Complexes.

Artificial light harvesting, a process that involves converting sunlight into chemical potential energy, is considered to be a promising part of the overall solution to address urgent global energy challenges. Conjugated polyelectrolyte complexes (CPECs) are particularly attractive for this purpose due to their extended electronic states, tunable assembly thermodynamics, and sensitivity to their local environment. Importantly, ionically assembled complexes of conjugated polyelectrolytes can act as efficient donor-acceptor pairs for electronic energy transfer (EET). However, to be of use in material applications, we must understand how modifying the chemical structure of the CPE backbone alters the EET rate beyond spectral overlap considerations. In this report we investigate the dependence of the EET efficiency and rate on the electronic structure and excitonic wave function of the CPE backbone. To do so, we synthesized a series of alternating copolymers where the electronic states are systematically altered by introducing comonomers with electron withdrawing and electron-rich character while keeping the linear ionic charge density nearly fixed. We find evidence that the excitonic coupling may be significantly affected by the exciton delocalization radius, in accordance with analytical models based on the line-dipole approximation and quantum chemistry calculations. Our results imply that care should be taken when selecting CPE components for optimal CPEC EET. These results have implications for using CPECs as key components in water-based light-harvesting materials, either as standalone assemblies or as adsorbates on nanoparticles and thin films.

Interpolyelectrolyte complexes of a biguanide cationic polyelectrolyte: Formation of core/corona nanoparticles with double-hydrophilic diblock polyanion

Biguanide-based cationic polyelectrolytes are used as key components of interpolyelectrolyte complexes bolstering alginate hydrogel microcapsules employed in cell therapies. Nevertheless, electrostatic complexation of these unique polycations has not been studied...

Hybrid nanoreactors formed by interpolyelectrolyte complex formation: a colloidal platform for light-driven catalysis

Micellar interpolyelectrolyte complexes are introduced as versatile soft matter matrices for light-driven hydrogen evolution catalysis.

Self-assembly of interpolyelectrolyte complexes and mixed micelles from guanidinium and phosphonate derivatives of p–tert–butylthiacalix[4]arene and solubilization of paclitaxel

In this work, supramolecular assemblies based on p–tert–butylthiacalix[4]arene derivatives functionalized with charged guanidinium and phosphonate fragments in the 1,3–alternate conformation were obtained in the presence of the surfactants. Two main approaches based on the macrocyclic compounds have been presented for supramolecular assembling, i.e. (i) the use of two oppositely charged macrocyclic compounds forming interpolyelectrolyte complexes; and (ii) the use of ionogenic macrocycles and low molecular surfactants forming mixed micelles. Self-assembling properties of guanidinium and phosphonate derivatives of p–tert–butylthiacalix[4]arene and paclitaxel solubilization of interpolyelectrolyte complexes and mixed micelles were examined and compared for various compositions. The obtained supramolecular associates were further investigated to load hydrophobic anticancer drug paclitaxel that is insoluble in water and requires solubilization prior to application. It was established that mixed micelles containing thiacalix[4]arene with guanidinium fragments were more effective in solubilizing paclitaxel against interpolyelectrolyte approach. The micelles obtained in the presence of water-insoluble drug formed stable monodisperse colloidal system consisted of spherical particles (d = 192 ± 7 nm, ζ = 33 ± 4 mV for equimolar ratio of the components). The results offer a new strategy for the design of the interpolyelectrolyte complexes based on the macrocyclic building blocks for the solubilization of water-insoluble drugs.

Characteristics of Interpolyelectrolyte Complexes Based on Different Types of Pectin with Eudragit® EPO as Novel Carriers for Colon-Specific Drug Delivery.

Given that pectin is a well-known substance used for drug delivery, we aimed to obtain and further examine the efficacy of interpolyelectrolyte complexes based on citrus or apple pectin and the Eudragit® EPO for using these carriers in oral drug delivery. To characterize the physicochemical properties of these compounds, turbidity, gravimetry, viscosity, elementary analysis, FTIR spectroscopy, and DSC analysis were utilized. Diffusion transport characteristics were evaluated to assess the swelling ability of the matrices and the release of diclofenac sodium. To examine the release parameters, mathematical modeling was performed by using the Korsmayer-Peppas and Logistic equations as well. During the turbidity study, stoichiometry compositions were selected for the developed IPECs EPO/PecA and EPO/PecC at pH values = 4.0, 5.0, 6.0, and 7.0. The FTIR spectra of the complexes were characterized by an increase in the intensity of the bands at 1610 cm-1 and 1400 cm-1. According to the DSC analysis, IPEC has a certain Tg = 57.3 °C. The highest release rates were obtained for IPEC EPO/PecC_1 and EPO/PecC_4. The mechanism of drug transport from the matrices IPEC EPO/PecC, IPEC EPO/PecA_3, and EPO/PecA_4 can be characterized as Super Case II. Anomalous release (non-Fickian release) is typical for IPEC EPO/PecA_1 and EPO/PecA_2. Thus, the resulting systems can be further used for the effective delivery of the drugs to the colon.

СУДА ЕРИТІН ПОЛИМЕРЛЕР МЕН ОЛАРДЫҢ ПОЛИКОМПЛЕКСТЕРІНІҢ СУЛЫ ЕРІТІНДІДЕГІ ҚАСИЕТТЕРІ

Abstract. The interaction of oppositely charged polyelectrolytes (sodium salt of carboxymethylcellulose (NaCMC), methylcellulose (MC), polyethylenimine (PEI) and polydimethyldiallylammonium chloride (PDMDAAС), and unifloc (UF)) in an aqueous environment was studied using the methods of viscometry, spectrophotometry and macroelectrophoresis. It has been established that the interaction of these polyelectrolytes is accompanied by a significant decrease in reduced viscosity (up to 0.1-0.15 dl/g, which is typical for compacted macromolecules of globular proteins), an increase in optical density and an inversion of the sign of the electrokinetic potential. All this indicates the formation of interpolymer complexes from interacting cationic and anionic polyelectrolytes. Experimental results of studying the properties of water soluble polymers and their polyelectrolyte complexes in aqueous solutions at the water/air interface are described and discussed. It has been shown that complex formation in relatively simple systems is accompanied by changes in the pH of the medium, optical, hydrodynamic, electrochemical and other properties of macromolecules. In the systems we studied, the interaction of the system components is not accompanied by variations in the pH of the medium, therefore, information about the interaction of water-soluble polyelectrolytes in the systems we studied was obtained based on viscometric and spectrophotometric titration data, as well as from changes in the electrokinetic potential of macromolecules. The study of the electrokinetic potential showed that the formation of interpolymer complexes in the systems under consideration is accompanied by significant changes in the electrokinetic potential of macromolecules. A study of the properties of mixtures of aqueous solutions of Na-CMC, MC, UF with polydimethyldiallylammonium chloride and polyethylenimine indicates the formation of interpolyelectrolyte complexes that have a more compact structure than the original macromolecules. Key words: polyelectrolytes; flocculation; cross-linking; stability; interpolymer complexes; optical density; polymer.

Ag2O-Containing Biocidal Interpolyelectrolyte Complexes on Glass Surfaces-Adhesive Properties of the Coatings.

Biocidal coatings are of great interest to the healthcare system. In this work, the biocidal activity of coatings based on a complex biocide containing polymer and inorganic active antibacterial components was studied. Silver oxide was distributed in a matrix of a positively charged interpolyelectrolyte complex (IPEC) of polydiallyldimethylammonium chloride (PDADMAC) and sodium polystyrene sulfonate (PSS) using ultrasonic dispersion, forming nanoparticles with an average size of 5-6 nm. The formed nanoparticles in the matrix are not subject to agglomeration and changes in morphology during storage. It was found that the inclusion of silver oxide in a positively charged IPEC allows a more than 4-fold increase in the effectiveness of the complex biocide against E. coli K12 in comparison with the biocidal effect of PDADMAC and IPEC. Polycation, IPEC, and the IPEC/Ag2O ternary complex form coatings on the glass surface due to electrostatic adsorption. Adhesive and cohesive forces in the resulting coatings were studied with micron-scale coatings using dynamometry. It was found that the stability of the coating is determined primarily by adhesive interactions. At the macro level, it is not possible to reliably identify the role of IPEC formation in adhesion. On the other hand, use of the optical tweezers method makes it possible to analyze macromolecules at the submicron scale and to evaluate the multiple increase in adhesive forces when forming a coating from IPEC compared to coatings from PDADMAC. Thus, the application of ternary IPEC/Ag2O complexes makes it possible to obtain coatings with increased antibacterial action and improved adhesive characteristics.

Soil improvement by biomass polyions and compaction: Reinforcement, biodegradation resistance, and retention of heavy metal ions

Biomass-based alternatives to soil improvement by cement in geotechnical applications are increasingly considered owing to their renewability and low carbon footprint. We have elaborated a method of soil improvement by which soil is treated with self-organizing biomass-derived polyions, carboxymethyl cellulose (CMC), and chitosan (CS) and is consequently compacted by rammer. CMC and CS interact electrostatically and self-assemble into interpolyelectrolyte complexes (IPEC) having the morphology of thin films imparting the superior mechanical properties to the soil composite. Curing of soil with CMC and CS at m(CMC+CS)/m(soil) ratios below 1% and compaction improved the unconfined compressive strength (qu) of soil up to 500 kPa in a wet state (ca. 17% moisture content) and 2.5 MPa in a dry state (ca. 0% moisture content). Due to the superior complexing properties of CMC and CS towards transition metal ions, soil treatment with IPEC notably suppressed the leaching of Cu2+, Pd2+, and Cd2+ metal ions from the soil. Despite the intrinsic biodegradability of CMC and CS, their IPEC complexes and soil-IPEC composites showed good resistance toward biodegradation by the cellulase enzyme. Excellent soil reinforcement, suppressed biodegradability, and chemical functionality of biomass-derived IPECs hold promise in utilizing renewable polymers in geotechnical practices of ground improvement addressing the needs of the sustainable use of resources.

Сорбционно-структурные свойства аэрогельных материалов на основе биополимеров

Nowadays aerogel materials (AM) are successfully used as entero- and applicative sorbents to eliminate excessive amounts of heavy metals and toxins from living organisms. Natural biopolymers alginate and chitosan, as well as various lignin derivatives are an inexhaustible raw material base for the creation of AM. A significant number of sorption materials and wound coatings of various types have been developed on their basis, which is associated not only with a wide range of physicochemical properties of these polymers and their already proven biomedical activity, but also with the prevalence and renewability of raw material sources for the production of these polymers, ease of extraction, the possibility of achieving a high degree of purification and relatively low price. The key stage in the AM synthesis is the formation of a strong hydrogel which is the AM framework. One of the technological methods is to obtain interpolyelectrolyte solid hydrogel. The paper proposes two different packaging models for the formation of the structure of interpolyelectrolyte complexes (IPEC) based on biopolymers pairs: sodium alginate (ALNa)–chitosan (CT) and sodium lignosulfonate (LSNa)–CT. The first model is a block model, in which the structure is formed due to ionic bonds between the carboxyl groups of ALNa and amino groups of CT, as well as a cooperative system of hydrogen bonds and dispersion interactions. The second model is an aggregation-tubular model, the structure of which is formed through ionic bonds between sulfogroups (within the rod-shaped supramolecular structures of LSNa) and amino groups of CT, as well as hydrogen bonds and dispersion interactions. Upon the process of IPEC drying under supercritical (SC-) conditions, strong phase contacts are formed, and the changes in the gel structure become irreversible. As a result, hydrophobic micro- and mesoporous two-component AMs differing in internal structure were obtained. AM ALNa–CT are characterized by fibrillar structure, and LSNa–CT – by structural elements of spherical shape. The obtained AM ALNa–CT and LSNa–CT have high sorption activity towards water and a wide range of heavy metals and low molecular weight toxins. The purpose of the work is to study the structural and sorption properties of AM based on biopolymers of various structural organization. A significant increase in the sorption activity of AM ALNa–CT in comparison with LSNa–CT is apparently due to their different supramolecular structure. There is a combination of several sorption mechanisms such as wetting, absorption, diffusion, osmotic phenomena and chemical interaction due to the highly porous structure of AM and the presence of sorption-active centers. For citation: Brovko O.S., Palamarchuk I.A., Gorshkova N.A., Bogdanovich N.I., Ivakhnov A.D. Sorption and Structural Properties of Aerogel Materials Based on Biopolymers. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 6, pp. 190–203. (In Russ.). https://doi.org/10.37482/0536-1036-2023-6-190-203

Development of Lyophilisates Based on Polymer-drug and Interpolyelectrolyte Complexes: Pharmacokinetic Assessment

Development of Lyophilisates Based on Polymer-drug and Interpolyelectrolyte Complexes: Pharmacokinetic Assessment

Malachite green-derivatized cationic comb-type copolymer acts as a photoresponsive artificial chaperone

Molecular chaperones play vital roles in various physiological reactions by regulating the folding and assembly of biomacromolecules. We have demonstrated that cationic comb-type copolymers exhibit chaperone activity for anionic biomolecules including DNA and ionic peptide via the formation of soluble interpolyelectrolyte complexes. The development of smart artificial chaperones that can be spatiotemporally controlled by a remotely guided signal would expand the functions of artificial chaperones. Herein, to enable photocontrol of chaperone activity, a cationic comb-type copolymer bearing malachite green as a photoresponsive unit was designed. We first prepared a series of carboxylic acid derivatives of malachite green identified a derivative that could be quickly and quantitatively converted to the cationic form from the nonionic form by photoirradiation. This derivative was conjugated to the cationic comb-type copolymer, poly(allylamine)-graft-poly(ethylene glycol) through a condensation reaction. Upon photoirradiation, the copolymer bearing 9 mol% malachite green enhanced the membrane disruptive activity of acidic peptide E5 and induced morphological changes in liposomes. This demonstration of photoresponsive activation of chaperoning activity of a copolymer suggests that the installation of carboxyl derivatives of malachite green will impart photoresponsiveness to various materials including biopolymers.

Biodegradable Water-Soluble Matrix for Immobilization of Biocidal 4-Hexylresorcinol.

Biocidal coatings have been used in biomedicine, cosmetology and the food industry. In this article, the coatings are described as being composed of non-stoichiometric polycomplexes, products of electrostatic coupling of two commercial biodegradable ionic polymers, anionic sodium alginate and cationic quaternized hydroxyethyl cellulose ethoxylate. Non-stoichiometric polycomplexes with a 5-fold excess of the cationic polymer were used for immobilizing hydrophobic biocidal 4-hexylresorcinol (HR). Being dispersed in water, the polycomplex particles were capable of absorbing a tenfold excess of HR in relation to the polycation. After deposition onto the plastic surface and drying, the aqueous polycomplex-HR composite formulation forms a transparent homogeneous coating, which swells slightly in water. The interpolyelectrolyte complex (IPEC) is substantially non-toxic. The incorporation of HR in the IPEC imparts antimicrobial activity to the resulting composite, in both aqueous solutions and coatings, against Gram-negative and Gram-positive bacteria and yeast. The polysaccharide-based polycomplexes with embedded HR are promising for the fabrication of biocidal films and coatings.