Biocompatibility of colloidal polypyrrole.

The excellent electroconductive properties of polypyrrole (PPy) predetermine its use as cell-instructive or biosensing biomaterial. PPy has potential for application in a physiological environment, and here the cytotoxicity, antioxidant capacity, modulation of neutrophil oxidative burst, antibacterial activity of colloidal PPy stabilized with polyvinylpyrrolidone (PVP), and long-term stability under physiological conditions are reported. Besides, long-term stability under physiological conditions is also provided.

Method for polypyrrole coating, and the example of its use for functionalization of polyurethane anisotropic electrospun mats.

The coating of polymer substrate with polypyrrole, described herein with detailed know-how, represents a novel technique of surface functionalization. The choice of oxidizing agent and the polymerization time both affect the properties of the thin polypyrrole layer. The specific conductivity, free surface energy, thickness, topography, and FTIR spectra of polypyrrole layer were determined.

Stimuli-responsive thin film composites of conducting polymers and cellulose nanocrystals for tissue engineering.

Thin composite films comprising two primary representatives of conducting polymers, poly(3, 4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), with eco-friendly cellulose nanocrystals (CNC) were prepared through electrochemical polymerization. The combination of CNC and PEDOT (or PPy) results in the formation of films with highly different surface topography and thickness. Intriguingly, different surface conductivity of PEDOT and PPy was revealed by atomic force microscopy albeit that the electrochemical properties were rather similar.

Chitosan/dialdehyde cellulose hydrogels with covalently anchored polypyrrole: Novel conductive, antibacterial, antioxidant, immunomodulatory, and anti-inflammatory materials.

In this work, conductive composite hydrogels with covalently attached polypyrrole (PPy) nanoparticles are prepared. Hydrogels are based on partially re-acetylated chitosan soluble at physiological pH without any artificial structural modifications or need for an acidic environment, which simplifies synthesis and purification. Low-toxic and sustainable dialdehyde cellulose (DAC) was used for crosslinking chitosan and covalent anchoring of PPy colloidal particles.

Pickering emulsions as an effective route for the preparation of bioactive composites: A study of nanocellulose/polyaniline particles with immunomodulatory effect.

Several studies have reported on application of cellulose particles for stabilizing Pickering emulsions (PE). Here we employ an original approach that involves using these particles as a part of advanced composite colloids made of conducting polymer polyaniline (PANI) and cellulose nanocrystals (CNC) or nanofibrils (CNF). PANI/cellulose particles were prepared using oxidative polymerization of aniline in situ in the presence of CNC or CNF.

Enzyme-Catalyzed Polymerization Process: A Novel Approach to the Preparation of Polyaniline Colloidal Dispersions with an Immunomodulatory Effect.

A green, nature-friendly synthesis of polyaniline colloidal particles based on enzyme-assisted oxidation of aniline with horseradish peroxidase and chitosan or poly(vinyl alcohol) as steric stabilizers was successfully employed. Physicochemical characterization revealed formation of particles containing the polyaniline emeraldine salt and demonstrated only a minor effect of polymer stabilizers on particle morphology. All tested colloidal particles showed antioxidation activity determined via scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals.

New approach to prepare cytocompatible 3D scaffolds via the combination of sodium hyaluronate and colloidal particles of conductive polymers.

Bio-inspired conductive scaffolds composed of sodium hyaluronate containing a colloidal dispersion of water-miscible polyaniline or polypyrrole particles (concentrations of 0.108, 0.054 and 0.

Hierarchically Structured Polystyrene-Based Surfaces Amplifying Fluorescence Signals: Cytocompatibility with Human Induced Pluripotent Stem Cell.

An innovative multi-step phase separation process was used to prepare tissue culture for the polystyrene-based, hierarchically structured substrates, which mimicked in vivo microenvironment and architecture. Macro- (pore area from 3000 to 18,000 µm; roughness (Ra) 7.2 ± 0.

Behaviour of Titanium Dioxide Particles in Artificial Body Fluids and Human Blood Plasma.

The growing application of materials containing TiO particles has led to an increased risk of human exposure, while a gap in knowledge about the possible adverse effects of TiO still exists. In this work, TiO particles of rutile, anatase, and their commercial mixture were exposed to various environments, including simulated gastric fluids and human blood plasma (both representing in vivo conditions), and media used in in vitro experiments. Simulated body fluids of different compositions, ionic strengths, and pH were used, and the impact of the absence or presence of chosen enzymes was investigated.

Formation of oleogels based on emulsions stabilized with cellulose nanocrystals and sodium caseinate.

Hypothesis: In the preparation of oleogels based on Pickering-emulsions, the choice of the preparation route is critical to withstand drying under ambient conditions, as it conditions the composition of the interfacial layer at the oil-water interface.

Experiments: Hexadecane and olive oil oleogels were prepared using an emulsion-template approach from oil-in-water emulsions formulated with cellulose nanocrystals (CNC) and sodium caseinate (CAS) added in different orders (CNC/CAS together; first CAS then CNC; first CNC then CAS). The oleogels were formed from preconcentrated emulsions by drying at ambient temperature.

Effect of Hofmeister Ions on Transport Properties of Aqueous Solutions of Sodium Hyaluronate.

Tracer diffusion coefficients obtained from the Taylor dispersion technique at 25.0 °C were measured to study the influence of sodium, ammonium and magnesium salts at 0.01 and 0.

Modulation of Differentiation of Embryonic Stem Cells by Polypyrrole: The Impact on Neurogenesis.

The active role of biomaterials in the regeneration of tissues and their ability to modulate the behavior of stem cells in terms of their differentiation is highly advantageous. Here, polypyrrole, as a representantive of electro-conducting materials, is found to modulate the behavior of embryonic stem cells. Concretely, the aqueous extracts of polypyrrole induce neurogenesis within embryonic bodies formed from embryonic stem cells.

Conducting composite films based on chitosan or sodium hyaluronate. Properties and cytocompatibility with human induced pluripotent stem cells.

Novel composite films combining biocompatible polysaccharides with conducting polyaniline (PANI) were prepared via the in-situ polymerization of aniline hydrochloride in the presence of sodium hyaluronate (SH) or chitosan (CH). The composite films possess very good cytocompatibility in terms of adhesion and proliferation of two lines of human induced pluripotent stem cells (hiPSC). Moreover, the cardiomyogenesis and even formation of beating clusters were successfully induced on the films.

The biocompatibility of polyaniline and polypyrrole 2: Doping with organic phosphonates.

Conducting polymers (CP) can be used as pH- and/or electro-responsive components in various bioapplications, for example, in 4D smart scaffolds. The ability of CP to maintain conductivity under physiological conditions is, therefore, their crucial property. Unfortunately, the conductivity of the CP rapidly decreases in physiological environment, as their conducting salts convert to non-conducting bases.

Caseinate-Stabilized Emulsions of Black Cumin and Tamanu Oils: Preparation, Characterization and Antibacterial Activity.

Caseinate-stabilized emulsions of black cumin () and tamanu () oils were studied in terms of preparation, characterization, and antibacterial properties. The oils were described while using their basic characteristics, including fatty acid composition and scavenging activity. The oil-in-water (o/w) emulsions containing the studied oils were formulated, and the influence of protein stabilizer (sodium caseinate (CAS), 1-12 wt%), oil contents (5-30 wt%), and emulsification methods (high-shear homogenization sonication) on the emulsion properties were investigated.

A New Hyaluronan Modified with β-Cyclodextrin on Hydroxymethyl Groups Forms a Dynamic Supramolecular Network.

A new hyaluronan derivative modified with β-cyclodextrin units (CD-HA) was prepared via the click reaction between propargylated hyaluronan and monoazido-cyclodextrin (CD) to achieve a degree of substitution of 4%. The modified hyaluronan was characterized by H-nuclear magnetic resonance spectroscopy (NMR) and size exclusion chromatography. Subsequent H-NMR and isothermal calorimetric titration experiments revealed that the CD units on CD-HA can form virtual 1:1, 1:2, and 1:3 complexes with one-, two-, and three-site adamantane-based guests, respectively.

In-Vitro Hemocompatibility of Polyaniline Functionalized by Bioactive Molecules.

Hemocompatibility is an essential prerequisite for the application of materials in the field of biomedicine and biosensing. In addition, mixed ionic and electronic conductivity of conducting polymers is an advantageous property for these applications. Heparin-like materials containing sulfate, sulfamic, and carboxylic groups may have an anticoagulation effect.

Electrochemically prepared composites of graphene oxide and conducting polymers: Cytocompatibility of cardiomyocytes and neural progenitors.

The cytocompatibility of cardiomyocytes derived from embryonic stem cells and neural progenitors, which were seeded on the surface of composite films made of graphene oxide (GO) and polypyrrole (PPy-GO) or poly(3,4-ethylenedioxythiophene) (PEDOT-GO) are reported. The GO incorporated in the composite matrix contributes to the patterning of the composite surface, while the electrically conducting PPy and PEDOT serve as ion-to-electron transducers facilitating electrical stimulation/sensing. The films were fabricated by a simple one-step electropolymerization procedure on electrically conducting indium tin oxide (ITO) and graphene paper (GP) substrates.

Role of protein-cellulose nanocrystal interactions in the stabilization of emulsion.

Hypothesis: The interactions between two bio-based emulsifiers, namely cellulose nanocrystals (CNC) and the surface active sodium caseinate (CAS), can influence the formation and stability of oil-in-water emulsion (O/W).

Experiments: After studying the interactions between CNC and CAS, in bulk, and at air-water and liquid-liquid interfaces, emulsions have been prepared through different routes of addition, at pH 7 and 3, at which CNC and CAS had repulsive and attractive interactions, respectively. The routes of addition were (1) CAS and CNC simultaneously, (2) CAS first followed by CNC in a subsequent emulsification step and (3) CNC first, followed by CAS.

Polyaniline colloids stabilized with bioactive polysaccharides: Non-cytotoxic antibacterial materials.

Colloidal polyaniline dispersions stabilized with biocompatible polysaccharides, sodium hyaluronate and chitosan (both with two different molecular weights), were successfully formulated. The colloids were characterized by UV-vis spectra, particle-size distributions and morphology, as well as by their biological properties in terms of cytotoxicity and antibacterial activity. Colloids containing both chitosan and hyaluronate showed only mild cytotoxicities, which were mainly governed by the concentration of conducting polyaniline in the colloid.

Exploring the Critical Factors Limiting Polyaniline Biocompatibility.

Today, the application of polyaniline in biomedicine is widely discussed. However, information about impurities released from polyaniline and about the cytotoxicity of its precursors aniline, aniline hydrochloride, and ammonium persulfate are scarce. Therefore, cytotoxicity thresholds for the individual precursors and their combinations were determined (MTT assay) and the type of cell death caused by exposition to the precursors was identified using flow-cytometry.

The behaviour of hyaluronan solutions in the presence of Hofmeister ions: A light scattering, viscometry and surface tension study.

Dynamic light scattering (DLS), viscosity and surface tension (SFT) measurements were used to characterize influence of salts containing ions of Hofmeister series (NaSO, (NH)SO, NaSCN, NHSCN and NaCl) on the behaviour of hyaluronan in diluted solutions at a temperature range of 15-45 °C. The results of the study showed that chaotropic and kosmotropic ions notably influenced the folding and unfolding of hyaluronan coils due to interactions between a respective ion and hydrophilic or hydrophobic patches present in the backbone of the polymer chains. This was mainly proved by viscosity and light scattering measurements.

The biocompatibility of polyaniline and polypyrrole: A comparative study of their cytotoxicity, embryotoxicity and impurity profile.

Conducting polymers (CP), namely polyaniline (PANI) and polypyrrole (PPy), are promising materials applicable for the use as biointerfaces as they intrinsically combine electronic and ionic conductivity. Although a number of works have employed PANI or PPy in the preparation of copolymers, composites, and blends with other polymers, there is no systematic study dealing with the comparison of their fundamental biological properties. The present study, therefore, compares the biocompatibility of PANI and PPy in terms of cytotoxicity (using NIH/3T3 fibroblasts and embryonic stem cells) and embryotoxicity (their impact on erythropoiesis and cardiomyogenesis within embryonic bodies).

Polyaniline cryogels: Biocompatibility of novel conducting macroporous material.

Polyaniline cryogel is a new unique form of polyaniline combining intrinsic electrical conductivity and the material properties of hydrogels. It is prepared by the polymerization of aniline in frozen poly(vinyl alcohol) solutions. The biocompatibility of macroporous polyaniline cryogel was demonstrated by testing its cytotoxicity on mouse embryonic fibroblasts and via the test of embryotoxicity based on the formation of beating foci within spontaneous differentiating embryonic stem cells.