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Functional gold nanoparticles (AuNPs) are commonly used to enhance the response of optical affinity biosensors. In this work, we investigated the effect of preparation conditions on functional properties of AuNPs functionalized with antibody (Ab-AuNPs), specifically AuNPs with antibody against carcinoembryonic antigen (CEA) covalently attached via carboxy-terminated oligo-ethylene thiolate linker layer. The following parameters of preparation of Ab-AuNP have been found to have a significant effect on Ab-AuNP performance in affinity biosensors: the time of reaction of activated AuNPs with antibody, concentrations of antibody and amino-coupling reagents, and composition of immobilization buffer (molarity and salt content). In contrast, pH of immobilization buffer has been demonstrated to have only a minor influence. Our experiments showed that the Ab-AuNPs prepared under optimum conditions offered a binding efficiency of Ab-AuNPs to CEA as high as 63%, which is more than 4 times better than the best efficiencies reported for similar functional AuNPs so far. We employed these Ab-AuNPs with a surface plasmon resonance (SPR) biosensor for the detection of CEA and showed that the Ab-AuNPs enhanced the sensor response to CEA by a factor of 1000. We also demonstrated that the Ab-AuNPs allow the biosensor to detect CEA at concentrations as low as 12 and 40 pg/mL in buffer and 50% blood plasma, respectively.
- MeSH
- imobilizační protilátky chemie MeSH
- karcinoembryonální antigen analýza krev MeSH
- koncentrace vodíkových iontů MeSH
- kovové nanočástice chemie MeSH
- lidé MeSH
- limita detekce MeSH
- povrchová plasmonová rezonance metody MeSH
- pufry MeSH
- zlato chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
Remote detection of hydrogen, without the utilization of electronic component or elevated temperature, is one of the hot topics in the hydrogen technology and safety. In this work, the design and realization of the optical fiber-based hydrogen sensor with unique characteristics are proposed. The proposed sensor is based on the gold-coated multimode fiber, providing the plasmon properties, decorated by the IRMOF-20 layer with high selectivity and affinity toward hydrogen. The IRMOF-20 layer was grown by a surface-assisted technique, and its formation and properties were studied using X-ray photoelectron spectroscopy, Raman, X-ray diffraction, and Brunauer-Emmett-Teller techniques. Simultaneous ellipsometry results indicate the apparent changes of the refractive index of the IRMOF-20 layer due to hydrogen sorption. As results, the presence of hydrogen led to the pronounced changes of plasmon band wavelength position as well as its intensity increase. The proposed hydrogen sensors were favorably distinguished by a high response/recovery rate, excellent selectivity toward the hydrogen, very low temperature dependency, functionality at room or lower temperature, insensitivity toward the humidity, and the presence of CO2, CO, or NO2. Additionally, the proposed hydrogen sensor showed good reversibility, reproducibility, and long-term stability.
The piezoelectric sensor (quartz crystal microbalance, QCM) was used to monitor cell adhesion in real time. Two cell lines, rat epithelial cells (WB F344) and lung melanoma cells (B16F10) were used. The cells were adhered and grown on the gold surface of the sensor pre-coated with adsorbed layer of extracellular matrix proteins as vitronectin and laminin. The process of cell attachment and spreading on the gold surface was continuously monitored and displayed by changes of the resonant frequency Deltaf and resistance DeltaR values of the piezoelectric resonators. The initial phase of cell attachment and spreading induced a decrease of frequency and increase of resistance relating viscoelastic properties of the cell monolayer on the sensing surface. The steady-state of both shifts was achieved after a few hours. The presence and state of cells on the surface was confirmed by fluorescent microscopy. The obtained results demonstrate that the piezoelectric sensor is suitable for studies of the cell adhesion processes. Thus obtained cell-based biosensor has potential for identification and screening of biologically active drugs and other biomolecules affecting cellular shape and attachment.
- MeSH
- biosenzitivní techniky přístrojové vybavení MeSH
- buněčná adheze fyziologie MeSH
- buněčné linie MeSH
- financování organizované MeSH
- krysa rodu rattus MeSH
- nádorové buněčné linie MeSH
- vitronektin MeSH
- zlato MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
We have investigated the application of Ar plasma for creation of nanostructured ultra high molecular weight polyethylene (PE) surface in order to enhance adhesion of mouse embryonic fibroblasts (L929). The aim of this study was to investigate the effect of the interface between plasma-treated and gold-coated PE on adhesion and spreading of cells. The surface properties of pristine samples and its modified counterparts were studied by different experimental techniques (gravimetry, goniometry and X-ray photoelectron spectroscopy (XPS), electrokinetic analysis), which were used for characterization of treated and sputtered layers, polarity and surface chemical structure, respectively. Further, atomic force microscopy (AFM) was employed to study the surface morphology and roughness. Biological responses of cells seeded on PE samples were evaluated in terms of cell adhesion, spreading, morphology and proliferation. Detailed cell morphology and intercellular connections were followed by scanning electron microscopy (SEM). As it was expected the thickness of a deposited gold film was an increasing function of the sputtering time. Despite the fact that plasma treatment proceeded in inert plasma, oxidized degradation products were formed on the PE surface which would contribute to increased hydrophilicity (wettability) of the plasma treated polymer. The XPS method showed a decrease in carbon concentration with increasing plasma treatment. Cell adhesion measured on the interface between plasma treated and gold coated PE was inversely proportional to the thickness of a gold layer on a sample.
- MeSH
- biokompatibilní potahované materiály * chemie farmakologie MeSH
- buněčné linie MeSH
- myši MeSH
- plazmové plyny chemie MeSH
- polyethyleny * chemie farmakologie MeSH
- povrchové vlastnosti MeSH
- testování materiálů * MeSH
- zlato * chemie farmakologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Gold nanoparticles represent nanosized colloidal entities with high relevance for both basic and applied research. When gold nanoparticles are functionalized with polymer-molecule ligands, hybrid nanoparticles emerge whose interactions with the environment are controlled by the polymer coating layer: Colloidal stability and structure formation on the single particle level as well as at the supracolloidal scale can be enabled and engineered by tailoring the composition and architecture of this polymer coating. These possibilities in controlling structure formation may lead to synergistic and/or emergent functional properties of such hybrid colloidal systems. Eventually, the responsivity of the polymer coating to external triggers also enables the formation of hybrid supracolloidal systems with specific dynamic properties. This review provides an overview of fundamentals and recent developments in this vibrant domain of materials science.
In this work, we present a study on reusable thin metal film resistivity-based sensor for direct measurement of binding of thiol containing molecules in liquid samples. While in bulk conductors the DC current is not influenced by the surface events to a measureable degree in a thin metal layer the electrons close to the surface conduct a significant part of electricity and are influenced by the surface interactions. In this study, the thickness of the gold layer was kept below 100 nm resulting in easily measureable resistivity changes of the metal element upon a surface SH-groups binding. No further surface modifications were necessary. Thin film gold layers deposited on a glass substrate by vacuum sputtering were photolithographically structured into four sensing elements arranged in a Wheatstone bridge to compensate for resistance fluctuations due to the temperature changes. Concentrations as low 100 pM provided measureable signals. The surface after the measurement could be electrolytically regenerated for next measurements.
Recently nanoparticle enhanced Laser Induced Breakdown Spectroscopy (NELIBS) is getting a growing interest as an effective alternative method for improving the analytical performance of LIBS. On the other hand, the plasmonic effect during laser ablation can be used for a different task rather than elemental analysis. In this paper, the dependence of NELIBS emission signal enhancement on nanoparticle-protein solutions dried on a reference substrate (metallic titanium) was investigated. Two proteins were studied: Human Serum Albumin (HSA) and Cytochrome C (CytC). Both proteins have a strong affinity for the gold nanoparticles (AuNPs) due to the bonding between the single free exterior thiol (associated with a cysteine residue) and the gold surface to form a stable protein corona. Then, since the protein sizes are vastly different, a different number of protein units is needed to cover AuNP surface to form a protein layer. The NP-protein solution was dropped and dried onto the titanium substrate. Then the NELIBS signal enhancement of Ti emission lines was correlated to the solution characteristics as determined with Dynamic Light Scattering (DLS), Surface Plasmon Resonance (SPR) spectroscopy and Laser Doppler Electrophoresis (LDE) for ζ-potential determination. Moreover, the dried solutions were studied with TEM (Transmission Electron Microscopy) for the inspection of the inter-particle distance. The structural effect of the NP-protein conjugates on the NELIBS signal reveals that NELIBS can be used to determine the number of protein units required to form the nanoparticle-protein corona with good accuracy. Although the investigated NP-protein systems are simple cases in biological applications, this work demonstrates, for the first time, a different use of NELIBS that is beyond elemental analysis and it opens the way for sensing the nanoparticle protein corona.
- MeSH
- kovové nanočástice * MeSH
- lasery MeSH
- lidé MeSH
- proteinová korona * MeSH
- spektrální analýza MeSH
- zlato MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The healing effects of silver and gold nanoparticles (AgNPs, AuNPs) are already known from ancient times. In addition considering to their antibacterial and anti-inflammatory effects speculations are being lead with respect to these nanoparticles (NPs) also about enhancement of skin penetration properties. In this work the interactions of pig skin (PS) layers and ointments with additions of AgNPs or AuNPs prepared by standard procedures and also by "green" synthesis in a different weight proportion by vibrational spectroscopy were studied. Spectra of untreated skin and skin treated by pure ointment were measured, as well as by ointment modified by vitamins without addition of NPs or with different proportion of NPs. Kinetics of interactions of modified ointments with skin was monitored during two hours with a five-minutes interval between each two consecutive measurements. The obtained series of spectra were analyzed by multivariate statistical methods namely Partial Least Squares (PLS), Principal Component Analysis (PCA) and Soft Independent Modelling of Class Analogy (SIMCA) which revealed observation of spectral changes in time-dependent spectra and variations of the peak intensity ratios. The study showed that the effects of quantity and type of NPs on skin penetration characteristics are evident.
- MeSH
- antibakteriální látky aplikace a dávkování MeSH
- antiflogistika aplikace a dávkování MeSH
- kovové nanočástice aplikace a dávkování MeSH
- kožní absorpce účinky léků MeSH
- kůže metabolismus MeSH
- masti aplikace a dávkování MeSH
- prasata MeSH
- spektrální analýza metody MeSH
- stříbro aplikace a dávkování MeSH
- vitaminy aplikace a dávkování MeSH
- zlato aplikace a dávkování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Adsorption properties of protein Papain at the solid|liquid (0.1 M KCl) interfaces of different hydrophobicity [highly oriented pyrolytic graphite (HOPG), bare gold, CH3, OH, and COOH-terminated self-assembled monolayers on gold] were studied by a combined quartz crystal microbalance and atomic force microscopy techniques. It was found that Papain forms an incomplete monolayer at hydrophobic interfaces (HOPG and CH3-terminated substrate), whereas on more hydrophilic ones, a complete monolayer formation was always observed with either the onset of the formation of a second layer (bare gold substrate) or adsorption in a multilayer fashion, possibly a bilayer formation (OH-terminated substrate). The surface concentration and compact monolayer film thickness was much lower on the COOH-terminated substrate compared to other surfaces studied. This result was explained by partial dissociation of the interfacial COOH groups leading to additional electrostatic interactions between the positively charged protein domains and negatively charged carboxylate anions, as well as to local pH changes promoting protein denaturation.
