Robert Horvath

Robert Horvath
Hungarian Academy of Sciences | HAS · Institute of Technical Physics and Materials Science

PhD

About

166
Publications
29,740
Reads
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2,943
Citations
Introduction
Development and application of label-free optical biosensors in life sciences. --- www.nanobiosensorics.com --- - optical waveguide sensors (resonant waveguide grating, grating coupled interfeometry, metal-clad waveguides, optical waveguide lightmode spectroscopy) - cell adhesion and signalling - single cell manipulation and sensing - protein adsorption and self-assembly - layer by layer
Additional affiliations
July 2012 - present
Hungarian Academy of Sciences
Position
  • Head of Nanobiosensorics Laboratory and Momentum Fellowship holder
October 2008 - September 2012
Hungarian Academy of Sciences
Position
  • Senior Researcher, Marie Curie and OTKA Fellowships holder
September 2006 - October 2008
Cranfield University
Position
  • Marie Curie Postdoctoral Fellow
Education
September 1999 - September 2000
University of Copenhagen
Field of study
  • Graduate School of Biophysics
September 1992 - September 2001
Eötvös Loránd University
Field of study
  • Physics and Biophysics

Publications

Publications (166)
Article
Full-text available
A novel high-throughput label-free resonant waveguide grating (RWG) imager biosensor, the Epic® BenchTop (BT), was utilized to determine the dependence of cell spreading kinetics on the average surface density (vRGD) of integrin ligand RGD-motifs. vRGD was tuned over four orders of magnitude by co-adsorbing the biologically inactive PLL-g-PEG and t...
Article
Unlabelled: Biomimetic coatings with cell-adhesion-regulating functionalities are intensively researched today. For example, cell-based biosensing for drug development, biomedical implants, and tissue engineering require that the surface adhesion of living cells is well controlled. Recently, we have shown that the bacterial flagellar protein, flag...
Article
Herbs and traditional medicines have been applied for thousands of years, but researchers started to study their mode of action at the molecular, cellular and tissue levels only recently. Nowadays, just like in ancient times, natural compounds are still determining factors in remedies. To support this statement, the recently won Nobel Prize for an...
Article
Full-text available
The interaction of the anti-adhesive coating, poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) and its Arg-Gly-Asp (RGD) functionalized form, PLL-g-PEG-RGD, with the green tea polyphenol, epigallocatechin-gallate (EGCg) was in situ monitored. After, the kinetics of cellular adhesion on the EGCg exposed coatings were recorded in real-time. The...
Article
Full-text available
The invasiveness of cancer cells describes the metastasizing capability of a primary tumor. The straightforward detection and quantification of cancer cell invasion are important to predict the survival rate of a cancer patient and to test how anti-cancer compounds influence cancer progression. Digital holographic microscopy based M4 Holomonitor (H...
Article
Full-text available
Single-cell adhesion plays an essential role in biological and biomedical sciences, but its precise measurement for a large number of cells is still a challenging task. At present, typical force measuring techniques usually offer low throughput, a few cells per day, and therefore are unable to uncover phenomena emerging at the population level. In...
Article
Cytotoxic effects of the market leading broad-spectrum, synthetic herbicide product Roundup Classic, its active ingredient glyphosate (in a form of its isopropylamine (IPA) salt) and its formulating surfactant polyethoxylated tallowamine (POE-15) were determined on two murine cell lines, a neuroectodermal stem cell-like (NE-4C) and a high alkaline...
Article
Full-text available
Novel biosensors already provide a fast way to detect the adhesion of whole bacteria (or parts of them), biofilm formation, and the effect of antibiotics. Moreover, the detection sensitivities of recent sensor technologies are large enough to investigate molecular-scale biological processes. Usually, these measurements can be performed in real time...
Article
Full-text available
Water in oil emulsions have a wide range of applications from chemical technology to microfluidics, where the stability of water droplets is of paramount importance. Here, using an accessible and easily reproducible experimental setup we describe and characterize the dissolution of water in oil, which renders nanoliter-sized droplets unstable, resu...
Article
Full-text available
The glycocalyx is a cell surface sugar layer of most cell types that greatly influences the interaction of cells with their environment. Its components are glycolipids, glycoproteins, and oligosaccharides. Interestingly, cancer cells have a thicker glycocalyx layer compared to healthy cells, but to date, there has been no consensus in the literatur...
Article
Bacteria repellent surfaces and antibody-based coatings for bacterial assays have shown a growing demand in the field of biosensors, and have crucial importance in the design of biomedical devices. However, in-depth investigations and comparisons of possible solutions are still missing. The optical waveguide lightmode spectroscopy (OWLS) technique...
Article
Full-text available
Plants and fungi can be used for medical applications because of their accumulation of special bioactive metabolites. These substances might be beneficial to human health, exerting also anti-inflammatory and anticancer (antiproliferative) effects. We propose that they are mediated by influencing cellular adhesion and migration via various signaling...
Article
Full-text available
The high throughput, cost effective and sensitive quantification of cell adhesion strength at the single-cell level is still a challenging task. The adhesion force between tissue cells and their environment is crucial in all multicellular organisms. Integrins transmit force between the intracellular cytoskeleton and the extracellular matrix. This f...
Article
Full-text available
Numerical simulations and analytical calculations are performed to support the design of grating-coupled planar optical waveguides for biological sensing. Near cut-off and far from cut-off modes are investigated, and their characteristics and suitability for sensing are compared. The numerical simulations reveal the high sensitivity of the guided m...
Article
Full-text available
Binding force between biomolecules has a crucial role in most biological processes. Receptor-ligand interactions transmit physical forces and signals simultaneously. Previously, we employed a robotic micropipette both in live cell and microbead adhesion studies to explore the adhesion force of biomolecules such as cell surface receptors including s...
Article
Today, there is an intense demand for lab-on-a-chip and tissue-on-a-chip applications in basic cell biological research and medical diagnostics. A particular challenge is the implementation of advanced biosensor techniques in point-of-care testing utilizing human primary cells. In this study, a resonant waveguide grating (RWG)-based label-free opti...
Article
Full-text available
The beat in physical systems is a transparent and well-understood phenomenon. It may occur in forced oscillatory systems and as a result of the interference of two waves of slightly different frequencies. However, in chemical systems, the realization of the latter type of the beat phenomenon has been lacking. Here we show that a periodic titration...
Article
Full-text available
Fluidic flow plays important roles in colloid and interface sciences. Measuring adsorption, aggregation processes and living cell behavior under a fluidic environment with varied flow velocities in a parallel and high-throughput manner remains to be a challenging task. Here we introduced a method to monitor cell response to well-defined flow with v...
Article
Full-text available
Interfacial layers are important in a wide range of applications in biomedicine, biosensing, analytical chemistry and the maritime industries. Along with the growing number of applications, the analysis of these layer properties and understanding their behavior is becoming crucial. Label-free surface sensitive methods are excellent tools to monitor...
Article
Full-text available
The binding of integrin proteins to peptide sequences such as arginine-glycine-aspartic acid (RGD) is a crucial step in the adhesion process of mammalian cells. While these bonds can be examined between purified proteins and their ligands, live-cell assays are better suited to gain biologically relevant information. Here we apply a computer-control...
Article
Full-text available
The glycocalyx is thought to perform a potent, but not yet defined function in cellular adhesion and signaling. Since 95% of cancer cells have altered glycocalyx structure, this role can be especially important in cancer development and metastasis. The glycocalyx layer of cancer cells directly influences cancer progression, involving the complicate...
Article
Full-text available
Reliable measurement of the binding kinetics of low molecular weight analytes to their targets is still a challenging task. Often, the introduction of labels is simply impossible in such measurements, and the application of label-free methods is the only reliable choice. By measuring the binding kinetics of Ni(II) ions to genetically modified flage...
Article
Full-text available
Resonance, beats, and synchronization are general and fundamental phenomena in physics. Their existence and in-depth understanding of physical systems lead to several applications and technological developments facing our world today. Here we show the existence of chemical resonance, chemical beats, and frequency locking phenomenon in periodically...
Preprint
Full-text available
Water in oil emulsions have a wide range of applications from chemical technology to microflu- idics, where the stability of water droplets is of paramount importance. Here using an accessible and easily reproducible experimental setup we describe and characterize the dissolution of water in oil, which renders nanoliter-sized droplets unstable, res...
Article
Full-text available
Tissue-on-a-chip technologies are more and more important in the investigation of cellular function and in the development of novel drugs by allowing the direct screening of substances on human cells. Constituting the inner lining of vessel walls, endothelial cells are the key players in various physiological processes, moreover, they are the first...
Chapter
Biofunctional coatings are key elements of biosensors regulating interactions between the sensing surface and analytes as well as matrix components of the sample. These coatings can improve sensing capabilities both by amplifying the target signal and attenuating interfering signals originating from surface fouling (non-specific binding). Consideri...
Article
Full-text available
Although microliter-scale liquid handling with a handheld pipette is a routine task, pipetting nanoliter-scale volumes is challenging due to several technical difficulties including surface tension, adhesion and evaporation effects. We developed a fully automated piezoelectric micropipette with a precision of < 1 nanoliter, improving the efficiency...
Preprint
Full-text available
Although microliter scale liquid handling with a handheld pipette is a routine task, pipetting nanoliter scale volumes is challenging due to several technical difficulties including surface tension, adhesion and evaporation effects. We developed a fully automated piezoelectric micropipette with a precision of <1 nanoliter improving the efficiency o...
Article
Full-text available
Single-cell adhesion force plays a crucial role in biological sciences, however its in-depth investigation is hindered by the extremely low throughput and the lack of temporal resolution of present techniques. While atomic force microcopy (AFM) based methods are capable of directly measuring the detachment force values between individual cells and...
Article
Epigallocatechin-gallate (EGCG) is the main polyphenol ingredient of green tea. This compound is a strong antioxidant and oxidizes easily. Numerous studies demonstrated its beneficial effects on the human health, for example its anticancer and anti-inflammatory activity. In the body, EGCG is transported by serum albumin. EGCG easily oxidizes and th...
Article
Full-text available
The fluidic force microscope (FluidFM) can be considered as the nanofluidic extension of the atomic force microscope (AFM). This novel instrument facilitates the experimental procedure and data acquisition of force spectroscopy (FS) and is also used for the determination of single-cell adhesion forces (SCFS) and elasticity. FluidFM uses special pro...
Article
Characterization of the binding of functionalized microparticles to surfaces with a specific chemistry sheds light on molecular scale interactions. Polymer or protein adsorption are often monitored by colloid particle deposition. Force measurements on microbeads by atomic force microscopy (AFM) or optical tweezers are standard methods in molecular...
Poster
Full-text available
Cell adhesion is an important feature of cells, however processes regulating it has not been fully understood yet. The interaction between cells and surfaces is a complicated process caused by many factors. Amongst them, cell surface adhesion receptors play a key role and the integrin receptor molecule is one of them. It has been previously shown t...
Preprint
Full-text available
Cell cell and cell matrix adhesions are fundamental in all multicellular organisms. They play a key role in cellular growth, differentiation, pattern formation and migration. Cell-cell adhesion is substantial in the immune response, pathogen host interactions, and tumor development. The success of tissue engineering and stem cell implantations stro...
Preprint
Full-text available
Cell–cell and cell–matrix adhesions are fundamental in all multicellular organisms. They play a key role in cellular growth, differentiation, pattern formation and migration. Cell-cell adhesion is substantial in the immune response, pathogen-host interactions, and tumor development. The success of tissue engineering and stem cell implantations stro...
Article
Full-text available
Cell-cell and cell-matrix adhesions are fundamental in all multicellular organisms. They play a key role in cellular growth, differentiation, pattern formation and migration. Cell-cell adhesion is substantial in the immune response, pathogen-host interactions, and tumor development. The success of tissue engineering and stem cell implantations stro...
Article
SALEN- and SALAN-based complexes with catalytically active metal centers are very promising small molecules to be utilized as part of antioxidant therapies. Here we discuss a modified SALAN-type molecule armed with two phosphonate groups that significantly increase its water solubility and aid to furnish mono- or dinuclear complexes with Cu ²⁺ ions...
Article
Full-text available
Optical Waveguide Lightmode Spectroscopy (OWLS) is widely applied to monitor protein adsorption, polymer self-assembly, and living cells on the surface of the sensor in a label-free manner. Typically, to determine the optogeometrical parameters of the analyte layer (adlayer), the homogeneous and isotropic thin adlayer model is used to analyze the r...
Article
Full-text available
The field of extracellular vesicles (EVs) is an exponentially growing segment of biomedical sciences. However, the problems of normalisation and quantification of EV samples have not been completely solved. Currently, EV samples are standardised on the basis of their protein content sometimes combined with determination of the particle number. Howe...
Article
Micropatterning of living single cells and cell clusters over millimeter-centimeter scale areas is of high demand in the development cell-based biosensors. Micropatterning methodologies require both to have a suitable biomimetic support and printing technology. In this work we present the micropatterning of living mammalian cells on carboxymethyl d...
Article
Full-text available
This study is a discovery of interesting and far reaching properties of the world leading herbicide active ingredient glyphosate. Here we demonstrate the cell adhesion-modifying characteristics of glyphosate affecting cellular interactions via Arg-Gly-Asp (RGD)-dependent integrins. This conclusion was supported by the observations that a glyphosate...
Article
In the present study, we monitor the adsorption-desorption kinetics and adsorbed layer structure of the bacterial protein flagellin in the presence of Hofmeister salts by a surface sensitive label-free optical biosensor (optical waveguide lightmode spectroscopy, OWLS). The recorded OWLS data were analyzed by a computer code using a set of coupled d...
Article
Full-text available
Hydration, viscoelastic properties and dominant structure of thin polymer layers on the surface of waveguide material were evaluated using optical waveguide lightmode spectroscopy (OWLS) and quartz crystal microbalance (QCM) methods. The fundamentally different principles of the two applied label-free biosensors enable to examine analyte layers fro...
Article
Functionalized nanoparticles can penetrate into living cells and vesicles, opening up an extensive range of novel directions. For example, nanoparticles are intensively employed in targeted drug delivery and biomedical imaging. However, the real-time kinetics and dynamics of nanoparticle–living cell interactions remained uncovered. In this study, w...
Article
Full-text available
A high-throughput label-free resonant waveguide grating biosensor, the Epic BenchTop, was utilized to in situ monitor the adhesion process of cancer cells on Arg-Gly-Asp tripeptide displaying biomimetic polymer surfaces. Using highly adherent human cervical adenocarcinoma (HeLa) cells as a model system, cell adhesion kinetic data with outstanding t...
Article
Rapid and inexpensive biosensor technologies allowing real-time analysis of biomolecular and cellular events have become the basis of next-generation cell-based screening techniques. Our work opens up novel opportunities in the application of the high-throughput label-free Epic BenchTop optical biosensor in cell toxicity studies. The Epic technolog...