The effective and widely tested biocides: Benzalkonium chloride, bronopol, chitosan, chlorhexidine and irgasan were added in different concentrations to atelocollagen matrices. In order to assess how ...these antibacterial agents influence keratinocytes cell growth, cell viability and proliferation were determined by using MTT assay. Acquired data indicated a low toxicity by employing any of these chemical substances. Furthermore, cell viability and proliferation were comparatively similar to the samples where there were no biocides. It means that regardless of the agent, collagen-cell-attachment properties are not drastically affected by the incorporation of those biocides into the substrate. Therefore, these findings suggest that these atelocollagen substrates enhanced by the addition of one or more of these agents may render effectiveness against bacterial stains and biofilm formation, being the samples referred to herein as "antimicrobial substrates" a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications.
The formulation, characterization, and anticipated antibacterial properties of hemp seed oil and its emulsions were investigated. The oil obtained from the seeds of
L. in refined and unrefined form ...was characterized using iodine, saponification, acid values, and gas chromatography, and was employed for the preparation of stable oil-in-water emulsions. The emulsions were prepared using pairs of non-ionic surfactants (Tween, Span). The effects of the emulsification method (spontaneous emulsification vs. high-intensity stirring), hydrophilic lipophilic balance (HLB), type and concentration of surfactant, and oil type on the size and distribution of the emulsion particles were investigated. It was found that the ability to form stable emulsions with small, initial particle sizes is primarily dependent on the given method of preparation and the HLB value. The most efficient method of emulsification that afforded the best emulsions with the smallest particles (151 ± 1 nm) comprised the high-energy method, and emulsions stable over the long-term were observed at HBL 9 with 10 wt % concentration of surfactants. Under high-intensity emulsification, refined and unrefined oils performed similarly. The oils as well as their emulsions were tested against the growth of selected bacteria using the disk diffusion and broth microdilution methods. The antibacterial effect of hemp seed oil was documented against
and
subsp.
. The formulated emulsions did not exhibit the antibacterial activity that had been anticipated.
Inimitable properties of carbon quantum dots as well as a cheap production contribute to their possible application in biomedicine especially as antibacterial and antibiofouling coatings. Fluorescent ...hydrophobic carbon quantum dots are synthesized by bottom-up condensation method and used for deposition of uniform and homogeneous Langmuir–Blodgett thin films on different substrates. It is found that this kind of quantum dots generates singlet oxygen under blue light irradiation. Antibacterial and antibiofouling testing on four different bacteria strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Pseudomonas aeruginosa) reveals enhanced antibacterial and antibiofouling activity of hydrophobic carbon dots thin films under blue light irradiation. Moreover, hydrophobic quantum dots show noncytotoxic effect on mouse fibroblast cell line. These properties enable potential usage of hydrophobic carbon quantum dots thin films as excellent antibacterial and antibiofouling coatings for different biomedical applications.
Development of new types of antibacterial coatings or nanocomposites is of great importance due to widespread multidrug-resistant infections including bacterial infections. Herein, we investigated ...biocompatibility as well as structural, photocatalytic, and antibacterial properties of photoactive hydrophobic carbon quantum dots/polyurethane nanocomposite. The swell-encapsulation-shrink method was applied for production of these nanocomposites. Hydrophobic carbon quantum dots/polyurethane nanocomposites were found to be highly effective generator of singlet oxygen upon irradiation by low-power blue light. Analysis of conducted antibacterial tests on Staphyloccocus aureus and Escherichia coli showed 5-log bactericidal effect of these nanocomposites within 60 min of irradiation. Very powerful degradation of dye (rose bengal) was observed within 180 min of blue light irradiation of the nanocomposites. Biocompatibility studies revealed that nanocomposites were not cytotoxic against mouse embryonic fibroblast cell line, whereas they showed moderate cytotoxicity toward adenocarcinomic human epithelial cell line. Minor hemolytic effect of these nanocomposites toward red blood cells was revealed.
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. Tests on fibroblasts revealed higher cytotoxicity of ammonium persulfate than aniline hydrochloride. Thanks to the synergic effect, both monomers in combination enhanced their cytotoxicities compared with individual substances. Thereafter, cytotoxicity of polyaniline doped with different acids (sulfuric, nitric, phosphoric, hydrochloric, and methanesulfonic) was determined and correlated with impurities present in respective sample (HPLC). The lowest cytotoxicity showed polyaniline doped with phosphoric acid (followed by sulfuric, methanesulfonic, and nitric acid). Cytotoxicity of polyaniline was mainly attributed to the presence of residual ammonium persulfate and low-molecular-weight polar substances. This is crucial information with respect to the purification of polyaniline and production of its cytocompatible form.
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•Cotton fabrics were coated in situ with conducting polymers, polyaniline or polypyrrole.•Silver nanoparticles were deposited on the surface.•Polypyrrole-coated cotton displayed ...antibacterial effect even without silver nanoparticles.•Cytotoxicity of cotton modified with polypyrrole was low.
Cotton fabric was coated with conducting polymers, polyaniline or polypyrrole, in situ during the oxidation of respective monomers. Raman and FTIR spectra proved the complete coating of substrates. Polypyrrole content was 19.3wt.% and that of polyaniline 6.0wt.%. Silver nanoparticles were deposited from silver nitrate solutions of various concentrations by exploiting the reduction ability of conducting polymers. The content of silver was up to 11wt.% on polypyrrole and 4 wt.% on polyaniline. The sheet resistivity of fabrics was determined. The conductivity was reduced after deposition of silver. The chemical cleaning reduced the conductivity by less than one order of magnitude for polypyrrole coating, while for polyaniline the decrease was more pronounced. The good antibacterial activity against S. aureus and E. coli and low cytotoxicity of polypyrrole-coated cotton, both with and without deposited silver nanoparticles, were recorded, and they promise a broad applicability of this material. Polyaniline-coated samples showed lower antibacterial activity and higher cytotoxicity compared to polypyrrole-based materials.
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•Polypyrrole was prepared by polymerization of pyrrole in the presence of dye.•Acid Blue 25 acts as a template to produce polypyrrole nanowires.•The conductivity was improved to ...60 S cm–1 with Acid Blue 25.•Polypyrrole prepared with Acid Blue 129 is in its native form less cytotoxic.•A simple purification substantially reduces the cytotoxicity in both cases.
Polypyrrole has been prepared by facile single-step chemical oxidative polymerization of the monomer in aqueous medium containing an anthraquinone dye, Acid Blue 25 or Acid Blue 129. The addition of the former structure-guiding agent results in the formation of polypyrrole nanowires with conductivity improved up from the units S cm–1 to 60 S cm−1. The second closely related dye, Acid Blue 129, had no impact on polymer morphology but in its presence the conductivity of polypyrrole also increased. It has been shown that the pyrrole concentration and oxidant-to-pyrrole mole ratio significantly affect the conductivity of synthesized polypyrrole. Polypyrroles have been characterized by FTIR and Raman spectroscopies to assess their molecular structure and intermolecular interactions. Considering the applications in biomedicine, the cytotoxicity of the samples has also been tested. Polypyrrole prepared with Acid Blue 129 has significantly lower cytotoxicity compared to that prepared with Acid Blue 25. The cytotoxicity of both polypyrroles can be eliminated by purification step. Low cytotoxicity combined with high conductivity enables application of these conducting polymers in biomedicine.
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•Hydrogels based on hyaluronan-lignin.•Creep/creep compliance and recovery, sweelling.
Effects of the addition of water soluble glycinated Kraft lignin (WS/KL) on the mechanical ...stability and biocompatibility of hyaluronan (NaHy) hydrogels were evaluated in this work. Water soluble lignin was obtained by the modification of Kraft lignin via a Mannich reaction. It was found that WS/KL is highly compatible with hyaluronan due to its improved water solubility, which favours its use in designing new advanced composite hydrogels. The effects of the concentration of WS/KL on morphological, swelling and creep/recovery behaviours of hyaluronan hydrogels were investigated. It was detected that the creep resistance and creep recovery of NaHy hydrogels was improved by the incorporation of up to 3% (w/w) of WS/KL. In contrast, the swelling capacity of hydrogels was decreased. The cytotoxicity tests proved that glycinated KL lignin limits the viability of cells only slightly, and the final hyaluronan/lignin hydrogels were non-toxic materials.
Aim of this study is to bring systematic comparison of structure and properties of the redox-active oxidation products of various phenylenediamines prepared under various acidic conditions. According ...to literature, structure and properties of the phenylenediamine oxidation products depend on the reaction conditions. Various ladder-like structures have widely been accepted in the literature since they can be potentially created from any phenylenediamine isomer. The presence of polyaniline-like structural units, however, has also been reported and often discussed. The conductivity of the reaction products was compared for the oxidation of o-, m- and p-phenylenediamine with ammonium peroxydisulfate in 1 M methanesulfonic acid, water, or in 1 M ammonium hydroxide. The combination of size exclusion chromatography with UV–visible, FTIR and Raman spectroscopies allow us to analyze the molecular structure of the oxidation products and to bring significant information on (1) the formation of oligomer and polymer fractions, (2) the content of benzenoid and quinonoid units suggesting the presence of polyaniline-like segments, and (3) the participation of phenazine-like constitutional units indicating the formation of polycyclic structures. The oxidation products have also been tested for their cytotoxicity in order to estimate their application potential in biomedicine. The dilution of extracts below 5% concentration was generally needed to suppress the cytotoxicity.
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•Oxidation of o-, m-, and p-phenylenediamine under various acidic conditions.•Systematic analysis of UV-visible, FTIR and Raman spectra of polyphenylenediamines.•Probable incorporation of 2,5-diamino-p-benzoquinone unit in poly(p-phenylenediamine).
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 0.036% ...w/w) were manufactured. For this purpose, either crosslinking with N-(3-dimethylaminopropyl-N-ethylcarbodiimide hydrochloride and N-hydroxysuccinimid or a freeze-thawing process in the presence of poly(vinylalcohol) was used. The scaffolds comprised interconnected pores with prevailing porosity values of ~ 30% and pore sizes enabling the accommodation of cells. A swelling capacity of 92-97% without any sign of disintegration was typical for all samples. The elasticity modulus depended on the composition of the scaffolds, with the highest value of ~ 50 kPa obtained for the sample containing the highest content of polypyrrole particles. The scaffolds did not possess cytotoxicity and allowed cell adhesion and growth on the surface. Using the in vivo-mimicking conditions in a bioreactor, cells were also able to grow into the structure of the scaffolds. The technique of scaffold preparation used here thus overcomes the limitations of conductive polymers (e.g. poor solubility in an aqueous environment, and limited miscibility with other hydrophilic polymer matrices) and moreover leads to the preparation of cytocompatible scaffolds with potentially cell-instructive properties, which may be of advantage in the healing of damaged electro-sensitive tissues.
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