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Introduction
Ádám Juhász is a research assistant at the University of Szeged. His research is focused on the thermodynamic characterization and the applications of association colloids, mainly micelles and polymer-surfactant structures. He is also skilled in the application of quasi-two-dimensional biomimetic sensors (QCM, SPR, OWLS) for the classification of nanosized drug carriers and the rheological investigation of colloidal systems.
Additional affiliations
July 2019 - present
January 2013 - June 2019
Education
September 2017 - June 2019
SZTE TTIK Doctoral School of Chemistry
Field of study
- Chemistry
September 2004 - June 2009
Publications
Publications (57)
Sub-nanometer-sized gold nanoclusters (Au NCs) were prepared via the spontaneous reduction of [AuCl4]−- ions with a hydroxamate derivative of L-tryptophan (Trp) natural amino acid (TrpHA). The prepared TrpHA-Au NCs possess intense blue emission (λem = 470 nm; λex = 380 nm) with a 2.13% absolute quantum yield and 1.47 ns average lifetime. The Trp-st...
Fluorescent gold nanoclusters have been successfully used as fluorescent markers for imaging of cells and tissues, and their potential role in drug delivery monitoring is coming to the fore. In addition, the development of biosensors using structure-tunable fluorescent nanoclusters is also a prominent research field. In the case of these sensor app...
Encapsulation possibilities of an extensively investigated neuroprotective drug (kynurenic acid, KYNA) are studied via lipid-based nanocarriers to increase the blood–brain barrier (BBB) specific permeability. The outcomes of various preparation conditions such as stirring and sonication time, concentration of the lipid carriers and the drug, and th...
The assembly of colloidal hyaluronic acid (HyA, as a polysaccharide) based hydrogel particles in an aqueous medium is characterized in the present paper, with an emphasis on the particular case of nanohydrogels formed by surfactant-neutralized polysaccharide networks. The structural changes and particle formation process of polysaccharide- and cati...
The non-steroid anti-inflammatory drug ketoprofen (KP) as a model molecule is encapsulated in different poly(lactide-co-glycolide) (PLGA) nanostructured particles, using Tween20 (TWEEN) and Pluronic F127 (PLUR) as stabilizers to demonstrate the design of a biocompatible colloidal carrier particles with highly controllable drug release feature. Base...
In the current work, we first present a simple synthesis method for the preparation of novel Vitamin-B1-stabilized few-atomic gold nanoclusters with few atomic layers. The formed nanostructure contains ca. eight Au atoms and shows intensive blue emissions at 450 nm. The absolute quantum yield is 3%. The average lifetime is in the nanosecond range a...
Systems far-from-equilibrium self-assemble into spatiotemporal structures. Here, we report on the formation of calcium alginate gardens along with their inorganic hybrids when a sodium alginate solution containing sodium phosphate in various compositions is injected into a calcium chloride reservoir. The viscoelastic properties of the membranes dev...
Encapsulation possibilities of two neuroprotective drugs of slightly different structures, kynurenic acid (KYNA) and its more hydrophilic analogue (SzR72), are studied in bovine serum albumin (BSA) nanoparticles (NPs) to increase their permeability through the blood-brain barrier (BBB). The effect of various preparation conditions such as protein c...
Encapsulation possibilities of two neuroprotective drugs of slightly different structures, kynurenic acid (KYNA) and its more hydrophilic analogue (SzR72), are studied in bovine serum albumin (BSA) nanoparticles (NPs) to increase their permeability through the blood-brain barrier (BBB). The effect of various preparation conditions such as protein c...
In actual work we clearly highlight in the first time the experimental factors (dominantly the concentration of the macromolecule components) influencing the formation of human serum albumin/hyaluronic acid (HSA/HyA) complex carrier particles which is not available in the literature despite the several published articles. We have shown that the cha...
In this review, we clearly highlight the importance of the detailed study of the interactions between noble metal colloids (nanoparticles (NPs) and nanoclusters (NCs)) with serum albumins (SAs) due to their rapidly growing presence in biomedical research. Besides the changes in the structure and optical property of SA, we demonstrate that the chara...
Effective applicability of serum albumin-hyaluronic acid (HyA) conjugates as potential drug delivery colloidal particles having d ∼ 220 – 260 nm average size has been presented for encapsulation of ibuprofen (IBU). Increased IBU content with drug loading of 30 % can be achieved via combination of the serum albumin proteins with biodegradable HyA po...
While numerous papers have been published according to the binary surfactant mixtures, only a few articles provide deeper information on the composition dependence of the micellization, and even less work attempts to apply the enhanced feature of the mixed micelles. The most important parameter of the self-assembled surfactants is the critical mice...
Introduction: The present work describes a calorimetry-founded characterization and design of a potential surfactant based colloidal drug delivery system. However, numerous research groups have published their outcomes according to the thermodynamic characterization of mixed micelle formation but only a few articles provide deeper information on th...
In this work, we firstly presented a simple encapsulation method to prepare thiamine hydrochloride (vitamin B1)-loaded asolectin-based liposomes with average hydrodynamic diameter of ca. 225 and 245 nm under physiological and acidic conditions, respectively. In addition to the optimization of the sonication and magnetic stirring times used for size...
Introduction: The present work describes a calorimetry-founded characterization and design of a potential surfactant-based colloidal drug delivery system. However, numerous research groups have published their outcomes according to the thermodynamic characterization of mixed micelle formation but only a few articles provide deeper information on th...
Analysis of in vitro dissolution profiles of encapsulated drugs usually involves the linearization of the applied mathematical model and sometimes transformation of the measured data. In this work, we demonstrate that a spreadsheet routine could provide a universal and reproducible data analysis strategy without the need for linearization. To test...
A protein-polysaccharide-based potential nanocarrier system have been developed via a simple, one-step preparation protocol without the use of long-term heating and the utilization of hardly removable crosslinking agents, surfactants, and toxic organic solvents. To the best of our knowledge, this article is the first which summarizes in detail the...
The interaction of neuroactive kynurenic acid (KYNA) with human serum albumin (HSA) was studied from both thermodynamic and structural point of view. This protein-drug interaction has high relevance in neuroscience, because the serum albumin-based KYNA-containing composites may act as a potential drug delivery system. Reversible binding of KYNA on...
This poster demonstrates the preparation and characterization of size-controlled liposomes in the diameter range of 50-250 nm for encapsulation of the fluorescent Rhodamin-B (RhoB) as a model drug molecule. During the experimental work three different encapsulation techniques have been studied and the dominant effect of the size, the structure and...
Target and appiled model: The studied system is specifically relevant in the neuroscience. Glutamate is the main excitatory neurotransmitter in the CNS. Kynurenic acid (KYNA) is the only known endogenous antagonist of ionotropic glutamate-receptors (GluR), and an increasing evidence suggests its neuroprotective capacity. At a higher, micromolar con...
Analytical methods based on the surface plasmon resonance (SPR) phenomena have
become widely used in the last decades as a result of the rapid development of the electronics and information technology background. In the early stages of the development of this technique, the method was primarily characterized by the study of compounds bound to the s...
This work presents a detailed description of a commonly used and low-cost evaluation process that is simply based on the nonlinear fitting of concentration-, time- and temperature-dependent surface plasmon resonance (SPR) sensorgrams in order to provide kinetic and thermodynamic characterization of a biologically relevant interaction. Regardless of...
A Szegedi Tudományegyetem Természettudományi és Informatikai Karának, Fizikai Kémiai és Anyagtudományi Tanszékén mûködõ Kolloidok és Nanoszerkezetû Anyagok Kutatócsoportunk kutatási profilja a csoport közel 25 éves fennállása óta számos területet érintett. A rétegszilikátok és réteges kettõs hidroxidok (LDH) által stabilizált félvezetõ nanorészecsk...
This paper presents some findings from the rheological and drug dissolution characterizations of hyaluronic acid (HyA)-based colloidal drug delivery systems. During this investigations the widely applied, non-steroidal, anti-inflammatory ketoprofen (KP) has been used as model drug. For the moderation of the hydrophilic character of HyA and encapsul...
The experiments in the present work describe, the synthesis and preparation, rheological, conductometric and titration calorimetry based characterization, and drug dissolution of different hyaluronic acid (HyA)-based colloidal drug delivery systems. During this investigations the hydrophobic ketoprofen (KP), one of the most used non-steroidal anti-...
Introduction: Detailed kinetic and thermodynamic characterization of physiological relevant receptor-ligand interactions provides several important data on the mechanisms of the drug binding and release process. Surface plasmon resonance (SPR) spectroscopy is capable of real-time monitoring of these interactions without use of labels via immobiliza...
The noble metal-based nanohybrid systems are in particularly focus due to their size-, shape-, composition-, aggregation- and surface roughnessdependent
optical properties. Different nanostructures can be synthesized and they were characterized by several techniques. The optical properties
were identified based UV-Vis and Fluorescence spectrophotom...
This work demonstrates the preparation, characterization, and drug dissolution of different hyaluronic acid (HyA)-based colloidal drug delivery systems containing hydrophobic ketoprofen (KP), a non-steroidal anti-inflammatory drug (NSAID), as the model drug molecule. Because of the highly hydrophilic character of HyA the cross-linked derivatives at...
The pH-responsive intelligent drug release facility of hydrophobically modified chitosan nanoparticles (Chit NPs) (d = 5.2 ± 1.1 nm) was presented in the case of poorly water soluble Ca2+ channel blocker nimodipine (NIMO) drug molecules. The adequate pH-sensitivity, i.e. the suitable drug carrier properties of the initial hydrophilic Chit were achi...
Kynurenic acid (KYNA) is a product of the tryptophan metabolism and it possess also anti- ulcerant properties, however, the application of KYNA for the treatment of gastroduodenal ulceration is limited, because the concentration of KYNA is very low in human gastric fluid (0.01 μM). The intercalation of KYNA molecules into biocompatible MgAl layered...
This work demonstrates the preparation, structural characterization, and the kinetics of the drug release of hyaluronic acid (HyA)-based colloidal drug delivery systems which contain hydrophobic ketoprofen (KP) as model molecule. Because of the highly hydrophilic character of HyA the cross-linked derivatives at different cross-linking ratio have be...
This article provides a detailed description of micellization of a binary nonionic surfactant system (Lutensol AP9 and AP20) at different compositions and temperatures in an aqueous medium. Critical micelle concentrations of the individual components (CMCi) and the mixed surfactants (CMCm) were determined via surface tension measurements in the tem...
The biomedical applications (e.g., diagnostic, in vivo, in vitro imaging, cancer therapy etc.) of nanosized gold particles require biocompatible preparation routes. In recent years a simple, one-pot, “green” synthetic routes for the preparation of gold nanoparticles (Au NPs) or nanoclusters (Au NCs) are in focus of interest [1-3].
In this work blu...
Quantitative detection of desired target chemicals in a sensitive and selective manner is extremely important to protect human health and environment. Nature has been a complete foundation of inspiration for the planning of sensitive and selective sensor techniques. For targeted and controlled drug delivery systems the study of the interactions bet...
For protein-based controlled drug delivery systems the study of the interactions between the carrier and a drug molecule play a determinant role in pharmaceutical developments. Detailed kinetic and thermodynamic characterization of protein-ligand interactions provide several important data on the mechanisms of the drug binding and release process....
In this work the interactions of L-cysteine (Cys), L-cysteinyl-tryptophan (Cys-Trp), L-glutathione (Glu-Cys-Gly, GSH) and lysozyme (LYZ) with gold-coated surface (Au 0) and tetrachloroaurate ions (AuCl4 ˉ) were studied in two(2D)- and three(3D)-dimensional systems, respectively. The irreversible bindings of the molecules onto gold surface via gold-...
This study demonstrates a one-step synthesis for the preparation of both adenosine monophosphate (AMP)-stabilized colloidal gold nanoparticles (AMP-Au NPs) and fluorescent gold nanoclusters (AMP-Au NCs). The dominant role of AMP:AuCl4⁻ molar ratios in the formation of diverse nanosized Au products was proved. The size, the structure and the unique...
Blue- and green-emitting gold nanostructures have been synthesized by spontaneous interactions of the tetrachloroaurate anions (AuCl4⁻) with L-histidine (His) and L-tryptophan (Trp) at 37 °C in aqueous medium. The dominant role of AuCl4⁻/amino acid molar ratios as well as the pH on the formation of gold nanoparticles (Au NPs) or nanoclusters (Au NC...
This paper presents a surface plasmon resonance (SPR) spectroscopy-based evaluation process which provides information on kinetic and thermodynamic aspects of the interactions between proteins and a drug molecule. Reversible binding of kynurenic acid (KYNA) on human (HSA) and bovine (BSA) serum albumin-modified gold sensor surface has been investig...
Interactions of L-cysteine (Cys), L-cysteinyl-tryptophan (Cys-Trp) and L-glutathione (γ-Glu-Cys-Gly, GSH) with gold-coated surface (Au⁰) and tetrachloroaurate ions (AuCl4⁻) were studied in two(2D)- and three(3D)-dimensional systems, respectively. The irreversible bindings of the molecules onto gold surface via gold-sulphur (Au-S) bonds were proven...
Investigation of receptor – ligand interactions play a determinant role in molecular life science. Detailed quantitative, kinetic and thermodynamic characterization of these biomolecular interactions may decisively contribute to the modern pharmaceutical developments. Surface plasmon resonance spectroscopy is capable of real-time monitoring of thes...
This work clearly demonstrates an evaluation process that is easily performed and is simply based on the fitting of temperature-dependent surface plasmon resonance (SPR) sensorgrams in order to provide detailed thermodynamic characterization of biologically relevant interactions. The reversible binding of kynurenic acid (KYNA) on human glutamate re...
The interactions between bovine serum albumin (BSA) and ibuprofen (IBU) were investigated at pH 3.0 and pH 7.4 by several two-(2D) and three-(3D) dimensional techniques to provide quantitative, kinetic and thermodynamic data on the BSA-IBU binding. Based on the results, the preparation of BSA-IBU composite nanoparticles (NPs) were successfully carr...
In the course of our previous work, the interactions of two peptide fragments (GluR1(201-230) and GluR1(231-259)) of human glutamate receptor (GluR1(201-300)) Polypeptide with kynurenic acid (KYNA) were investigated by surface plasmon resonance (SPR) spectroscopy. Besides quantitation of the interactions, the enthalpies of binding of KYNA on certai...
Precipitation of bovine serum albumin (BSA) by anionic surfactants with alkyl chains of increasing lengths (octyl, decyl, dodecyl sulfates) was studied at room temperature, at pH 3.0, in isotonic sodium chloride solution. The particle size of albumin, the zeta potential, the surface charge and fluorescent properties of BSA-surfactant composites wer...
In the course of our previous work, the interactions of two peptide fragments (GluR1201-230 and GluR1231-259) of human glutamate receptor (GluR1201-300) polypeptide with kynurenic acid (KYNA) were investigated by surface plasmon resonance (SPR) spectroscopy. Besides quantitation of the interactions, the enthalpies of binding of KYNA on certain pept...
Nanosilver-modified TiO2 and ZnO photocatalysts were studied against methicillin-resistant Staphylococcus aureus on the surface and against naturally occurring airborne microorganisms. The photocatalysts/polymer nanohybrid films were prepared by spray coating technique on the surface of glass plates and on the inner surface of the reactive light so...
The plasmonic Ag-TiO2 (with 0.5 wt% Ag) photocatalyst was prepared on P25 TiO2 surface. The presence of AgNPs on the titania was indicated by the UV–vis spectrum, which showed a plasmonic absorbance band in the visible range (λ
max = 455 nm). XPS measurements suggested that Ag was in metallic (Ag) and in oxide forms on TiO2. Ag-TiO2 photocatalyst a...
Silver functionalized TiO2/poly(etyl-acrylate co methyl-methacrylate) nanohybrid films were proved to inactivate nosocomial bacteria. The films were prepared on glass plates by spray coating technique and their thickness were 1.48±0.1 μm. During photocatalysis, the films were illuminated with visible LED-light source (λ = 405 nm). The optical and p...
A fluorescent lamp has increased weight of emission mix material on the metal coils forming the electrodes. The coating layer of emission mix material includes in the range of 70 weight % to 85 weight % alkaline earth carbonate content. The coating layer of emission mix material has a particle size distribution by volume with two maxima, and one of...
Bimetallic silver–gold nanoparticles (NPs) with different structures were prepared. Namely, silver–gold alloy and core(Ag)–shell(Au) type nanoparticles were synthesized at various Ag/Au ratios using only sodium citrate as reductant without any stabilizers. The synthesized NPs were characterized by different structure analysis methods. The unique op...
Questions
Questions (7)
Exact chemical structure means exact molar mass and not average molar mass of some kind mixture of homologs. So the Tween and Span series are not good.
Water-Water titrations are a good way to check for possible problems, especially the cleanliness of the ITC and your skills in cell filling. If a water-water titration works well the instrument is in good working order and your cell filling procedure is correct.
During this process, a small amount of water is added to the water-filled cell in several steps and the resulting heat effect is recorded. However, by increasing the amount of water injected (increasing its volume to ten times the usual 1-2 μm), a significantly larger heat effect can be recorded.
I would like to know what effects, presumably resulting from the design of the equipment, are responsible for the abrupt increase in the amount of detected heat.
We would like to determine the monomer (free) concentration of the ionic component in binary aqueous solutions of cationic and nonionic surfactants, above mixed CMC. We are looking for a cheap and simple (applicable at the student level) analytical method to carry out these measurements.
In general, the CMC results from the intersection between the regression straight line of the linearly dependent region and the straight line passing through the plateau. But before the plateau, we could detect a minimum region on the experimental curve. I would be wondering if there is a qualitative or quantitative explanation for the minimum surface tension near the cmc.
There has long been a debate among my colleagues about measuring the pH of aqueous colloids. As I see there is no general truth in the matter, so I ask this question below.
What is the best and most reliable method for measuring the pH of
- aqueous surfactants,
- aqueous polyelectrolyte and
- aqueous surfactant/polyelectrolyte systems?
There has long been a debate among my colleagues about measuring the pH of aqueous colloids. As I see there is no general truth in the matter, so I ask this question below.
What is the best and most reliable method for measuring the pH of aqueous surfactants, aqueous polyelectrolyte and aqueous surfactant / polyelectrolyte systems?
