Multifunctional nanoparticles for magnetic hyperthermia which simultaneously display antibacterial properties promise to decrease bacterial infections co-localized with cancers. Current methods synthesize such particles by multi-step procedures, and systematic comparisons of antibacterial properties between coatings, as well as measurements of specific absorption rate (SAR) during magnetic hyperthermia are lacking. Here we report the novel simple method for synthesis of magnetic nanoparticles with shells of oleic acid (OA), polyethyleneimine (PEI) and polyethyleneimine-methyl cellulose (PEI-mC). We compare their antibacterial properties against single gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria as well as biofilms. Magnetite nanoparticles (MNPs) with PEI-methyl cellulose were found to be most effective against both S. aureus and E. coli with concentration for 10% growth inhibition (EC10) of <150 mg/l. All the particles have high SAR and are effective for heat-generation in alternating magnetic fields.

• MeSH
• antibakteriální látky chemie   farmakologie   MeSH
• biofilmy účinky léků   MeSH
• Escherichia coli účinky léků   fyziologie   MeSH
• indukovaná hypertermie MeSH
• magnetické nanočástice chemie   MeSH
• methylcelulosa chemie   MeSH
• polyethylenimin chemie   MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• Staphylococcus aureus účinky léků   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Silver nanoparticles are versatile platforms with a variety of applications in the biomedical field. In this framework, their presence in biological media inevitably leads to the interaction with proteins thus conducting to the formation of biomolecular coronas. This feature alters the identity of the nanomaterial and may affect many biological events. These considerations motivated the investigation of protein adsorption onto the surface of polymer-stabilized AgNPs. The metallic colloids were coated by polyethyleneimine (PEI), polyvinylpyrrolidone (PVP), and poly(2-vinyl pyridine)-b-poly(ethylene oxide) (PEO-b-P2VP), and nanoparticle-protein interaction was probed by using a library of analytical techniques. The experimental data revealed a higher extent of protein adsorption at the surface of AgNPs@PVP whereas PEO-b-P2VP coating conducted to the least amount. The main component of the protein coronas was evidenced to be bovine serum albumin (BSA), which is indeed the protein at the highest abundancy in the model biological media. We have further demonstrated reduced cytotoxicity of the silver colloids coated by biomolecular coronas as compared to the pristine counterparts. Nevertheless, the protein coatings did not notably reduce the antimicrobial performance of the polymer-stabilized AgNPs. Accordingly, although the protein-repelling property is frequently targeted towards longer in vivo circulation of nanoparticles, we herein underline that protein coatings, which are commonly treated as artifacts to be avoided, may indeed enhance the biological performance of nanomaterials. These findings are expected to be highly relevant in the design of polymer-stabilized metallic colloids intended to be used in healthcare.

• MeSH
• antibakteriální látky farmakologie   MeSH
• ethylenoxid MeSH
• koloidy MeSH
• kovové nanočástice * MeSH
• polyethylenimin farmakologie   MeSH
• polymery farmakologie   MeSH
• povidon farmakologie   MeSH
• proteinová korona * metabolismus   MeSH
• pyridiny MeSH
• sérový albumin hovězí MeSH
• stříbro farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH

The use of noble metal nanoparticles in biomedical and biotechnological applications is nowadays well established. Particularly, silver nanoparticles (AgNPs) were proven to be effective for instance as a biocide agent. They also find applications in tumor therapies and sensing applications being encouraging tools for in-vivo imaging. In this framework, whenever they are in contact with living systems, they are rapidly coated by a protein corona thereby influencing a variety of biological events including cellular uptake, blood circulation lifetime, cytotoxicity and, ultimately, the therapeutic effect. Taking these considerations into account, we have explored the behavior of polymer-coated AgNPs in model protein environments focusing on the self-development of protein coronas. The polymers polyethyleneimine (PEI), polyvinylpyrrolidone (PVP) and poly(2-vinyl pyridine)-b-poly(ethylene oxide) (PEO-b-P2VP) were used as stabilizing agents. The chemical nature of the polymer capping remarkably influences the behavior of the hybrid nanomaterials in protein environments. The PEO-b-P2VP and PVP-stabilized AgNPs are essentially inert to the model proteins adsorption. On the other hand, the PEI-stabilized AgNPs interact strongly with bovine serum albumin (BSA). Nevertheless, the same silver colloids were evidenced to be stable in IgG and lysozyme environments. The BSA adsorption into the PEI-stabilized AgNPs is most probably driven by hydrogen bonding and van der Waals interactions as suggested by isothermal titration calorimetry data. The development of protein coronas around the AgNPs may have relevant implications in a variety of biological events. Therefore, further investigations are currently underway to evaluate the influence of its presence on the cytotoxicity, hemolytic effects and biocide properties of the produced hybrid nanomaterials.

• MeSH
• adsorpce MeSH
• dynamický rozptyl světla MeSH
• fluorescenční spektrometrie MeSH
• kalorimetrie MeSH
• koloidy chemie   MeSH
• kur domácí MeSH
• nanočástice ultrastruktura   MeSH
• polyethylenimin chemie   MeSH
• polymery chemie   MeSH
• povidon chemie   MeSH
• proteinová korona chemie   MeSH
• sérový albumin hovězí chemie   MeSH
• skot MeSH
• spektrofotometrie ultrafialová MeSH
• stříbro chemie   MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

We propose a label-free biosensor concept based on the charge state manipulation of nitrogen-vacancy (NV) quantum color centers in diamond, combined with an electrochemical microfluidic flow cell sensor, constructed on boron-doped diamond. This device can be set at a defined electrochemical potential, locking onto the particular chemical reaction, whilst the NV center provides the sensing function. The NV charge state occupation is initially prepared by applying a bias voltage on a gate electrode and then subsequently altered by exposure to detected charged molecules. We demonstrate the functionality of the device by performing label-free optical detection of DNA molecules. In this experiment, a monolayer of strongly cationic charged polymer polyethylenimine is used to shift the charge state of near surface NV centers from negatively charged NV- to neutral NV0 or dark positively charged NV+. Immobilization of negatively charged DNA molecules on the surface of the sensor restores the NV centers charge state back to the negatively charged NV-, which is detected using confocal photoluminescence microscopy. Biochemical reactions in the microfluidic channel are characterized by electrochemical impedance spectroscopy. The use of the developed electrochemical device can also be extended to nuclear magnetic resonance spin sensing.

• MeSH
• biosenzitivní techniky přístrojové vybavení   MeSH
• diamant chemie   MeSH
• DNA analýza   MeSH
• dusík chemie   MeSH
• elektrochemie MeSH
• laboratoř na čipu * MeSH
• polyethylenimin chemie   MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Food and feed technology and biotechnology benefit from the use of immobilised enzymes. New low-cost enzyme carriers exhibiting high biocompatibility and response to external magnetic field can substantially improve the application potential of immobilised enzyme systems. RESULTS: Ferrofluid-modified spent grain was used as a low-cost, biocompatible and magnetically responsive carrier for the immobilisation of Candida rugosa lipase. Several immobilisation procedures were tested using both native and poly(ethyleneimine)-modified magnetic spent grain. Activity of immobilised lipase per unit mass of carrier, operational stability, time stability and Michaelis constant were compared. In general, magnetic spent grain modified with poly(ethyleneimine) bound a smaller amount of active lipase than unmodified magnetic spent grain, but the operational and storage stabilities of enzyme immobilised on poly(ethyleneimine)-modified carrier were very high. CONCLUSION: Ferrofluid-modified spent grain can be a promising low-cost magnetic carrier for enzyme immobilisation, applicable e.g. in food and feed technology and biotechnology.

• MeSH
• biotechnologie MeSH
• Candida enzymologie   MeSH
• enzymy imobilizované * MeSH
• jedlá semena * MeSH
• lipasa * MeSH
• magnetismus * MeSH
• polyethylenimin MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Herein, we describe a new method for the synthesis of superhydrophilic poly(2-alkyl-2-oxazoline)s (PAOx) from poly(2-ethyl-2-oxazoline) (PEtOx). A well-defined linear polyethylenimine was prepared from PEtOx by controlled acidic hydrolysis of its side-chains followed by reacylation with different carboxylic acids. Using this protocol, we obtained a series of new hydrophilic PAOx containing side-chain ether groups with potential in biomaterials science. The relative hydrophilicity of the polymers was assessed, revealing that poly(2-methoxymethyl-2-oxazoline) (PMeOMeOx) is the most hydrophilic PAOx reported to date. Additionally, the amorphous poly(2-methoxy-ethoxy-ethoxymethyl-2-oxazoline) (PDEGOx) shows the lowest reported glass transition temperature (-25 °C) within the PAOx family to date. The biomedical potential of the prepared polymers was further fortified by an in vitro cytotoxicity study, where all polymers appeared to be noncytotoxic. The described synthetic protocol is universal and can be extremely versatile, especially for PAOx that are difficult to prepare by conventional cationic ring-opening polymerization due to the monomer interference and/or degradation.

• MeSH
• HeLa buňky MeSH
• hydrofobní a hydrofilní interakce MeSH
• lidé MeSH
• oxazoly chemie   MeSH
• polyethylenimin chemie   MeSH
• tranzitní teplota MeSH
• vitrifikace MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Kondagogu (Cochlospermum gossypium) gum (KG), a natural tree exudate, was investigated for its morphological, adsorption and metal interaction behavior with various toxic heavy metals (Pb, Cd, Ni, Cr and Fe). SEM, AFM and TEM techniques were used to study the morphological changes occurring after metal adsorption onto the biopolymer structure. The degree of biosorption of metals on KG biopolymer surfaces was assessed by small-angle X-ray scattering analysis. EDXA spectrum revealed that the ion-exchange mechanism plays a major role in the binding process between KG and metal ions. The higher electron density observed in the KG-Cd complex suggests that Cd is strongly bound to KG compared to the other metals. This work provides a potential platform for developing a hydrocolloid-based nanogel for bioremediation of environmental contaminants.

• MeSH
• adsorpce MeSH
• biodegradace MeSH
• biopolymery chemie   MeSH
• Bixaceae chemie   MeSH
• iontová výměna MeSH
• koloidy chemie   MeSH
• komplexní sloučeniny chemie   MeSH
• polyethylenglykoly chemie   MeSH
• polyethylenimin chemie   MeSH
• rostlinné extrakty chemie   MeSH
• těžké kovy chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Magnetic harvesting of microalgal biomass provides an attractive alternative to conventional methods. The approach to this issue has so far been pragmatic, focused mainly on finding cheap magnetic agents in combination with harvestable microalgae species. The aim of this work was to study experimentally and theoretically the mechanisms leading to cell-magnetic agent attachment/detachment using real experiments and predictions made by colloidal adhesion (XDLVO) model. Two types of well defined magnetic beads (MBs) carrying ion exchange functional groups (DEAE - diethylaminoethyl and PEI - polyethylenimine) were studied in connection with microalgae (Chlorella vulgaris). Optimal harvesting efficiencies (>90%) were found for DEAE and PEI MBs, while efficient detachment was achieved only for DEAE MBs (>90%). These findings were in accordance with the predictions by XDLVO model. Simultaneously there was found a discrepancy between the XDLVO prediction and the poor detachment of PEI MBs from microalgal surface. This can be ascribed to an additional interaction (probably covalent bonds) between PEI and algal surface, which the XDLVO model is unable to capture given by its non-covalent nature.

• MeSH
• biologické modely MeSH
• biomasa MeSH
• buněčná adheze MeSH
• Chlorella vulgaris izolace a purifikace   fyziologie   MeSH
• ethanolaminy chemie   MeSH
• iontová výměna MeSH
• koloidy MeSH
• magnetické jevy MeSH
• magnetické nanočástice chemie   MeSH
• mikrořasy izolace a purifikace   fyziologie   MeSH
• polyethylenimin chemie   MeSH
• povrchové vlastnosti MeSH
• průmyslová mikrobiologie metody   MeSH
• sladká voda mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Horseradish peroxidase (HRP)/H2O2-mediated crosslinking of polypeptides in inverse miniemulsion is a promising approach for the development of next-generation biocompatible and biodegradable nanogels. Herein, we present a fundamental investigation of the effects of three surfactants and their different concentrations on the (HRP)/H2O2-mediated nanogelation of poly[N5-(2-hydroxyethyl)-l-glutamine-ran-N5-propargyl-l-glutamine-ran-N5-(6-aminohexyl)-l-glutamine]-ran-N5-[2-(4-hydroxyphenyl)ethyl)-l-glutamine] (PHEG-Tyr) in inverse miniemulsion. The surfactants sorbitan monooleate (SPAN 80), polyoxyethylenesorbitan trioleate (TWEEN 85), and dioctyl sulfosuccinate sodium salt (AOT) were selected and their influence on the nanogel size, size distribution, and morphology was evaluated. The most effective nanogelation stabilization was achieved with 20 wt% nonionic surfactant SPAN 80. The diameter of the hydrogel nanoparticles was 230 nm (dynamic light scattering, DLS) and was confirmed also by nanoparticle tracking analysis (NTA) which showed the diameters ranging from 200 to 300 nm. Microscopy and image analyses showed that the nanogel in the dry state was spherical in shape and had number-average diameter Dn = 26 nm and dispersity Р= 1.91. In the frozen-hydrated state, the nanogel appeared porous and was larger in size with Dn = 182 nm and Р= 1.52. Our results indicated that the nanogelation of the polymer precursor required a higher concentration of surfactant than classical inverse miniemulsion polymerization to ensure effective stabilization. The developed polypeptide nanogel was radiolabeled with 125I, and in vivo biodistribution and blood clearance evaluations were performed. We found that the 125I-labeled nanogel was well-biodistributed in the bloodstream, cleared from mouse blood during 48 h by renal and hepatic pathways and did not provoke any sign of toxic effects.

• MeSH
• myši MeSH
• nanogely MeSH
• peptidy MeSH
• peroxid vodíku * MeSH
• polyethylenglykoly MeSH
• polyethylenimin MeSH
• povrchově aktivní látky * MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Magnetic resonance imaging using fluorinated contrast agents (19F MRI) enables to achive highcontrast in images due to the negligible fluorine background in living tissues. In this pilot study, we developed new biocompatible, temperature-responsive, and easily synthesized polymeric nanogels containing a sufficient concentration of magnetically equivalent fluorine atoms for 19F MRI purposes. The structure of the nanogels is based on amphiphilic copolymers containing two blocks, a hydrophilic poly[ N-(2-hydroxypropyl)methacrylamide] (PHPMA) or poly(2-methyl-2-oxazoline) (PMeOx) block, and a thermoresponsive poly[ N(2,2difluoroethyl)acrylamide] (PDFEA) block. The thermoresponsive properties of the PDFEA block allow us to control the process of nanogel self-assembly upon its heating in an aqueous solution. Particle size depends on the copolymer composition, and the most promising copolymers with longer thermoresponsive blocks form nanogels of suitable size for angiogenesis imaging or the labeling of cells (approximately 120 nm). The in vitro 19F MRI experiments reveal good sensitivity of the copolymer contrast agents, while the nanogels were proven to be noncytotoxic for several cell lines.

• MeSH
• fluor chemie   MeSH
• HeLa buňky MeSH
• hemolýza účinky léků   MeSH
• kontrastní látky škodlivé účinky   chemie   MeSH
• kultivované buňky MeSH
• kyseliny polymethakrylové chemie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• myši MeSH
• polyaminy chemie   MeSH
• polyethylenglykoly chemie   MeSH
• polyethylenimin chemie   MeSH
• polymerizace MeSH
• teplota MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH