Gold nanoparticles of two different sizes stabilized by a 15-mer peptide ligand specifically desi... more Gold nanoparticles of two different sizes stabilized by a 15-mer peptide ligand specifically designed for this purpose have been prepared in aqueous solution and characterized by UV-vis spectroscopy and TEM. The presence of the ligand and its binding mode to the particles via its four cystein thiols is evidenced by FTIR and NMR spectroscopy. Biotinylation of the particles via binding to a freely accessible lysine residue is demonstrated.
A preliminary investigation on a new class on electrocatalytic materials for the electroreduction... more A preliminary investigation on a new class on electrocatalytic materials for the electroreduction of organic halides is presented and discussed. The electrocatalysts are based on silver nanoparticles (Ag_NP), ad hoc synthesised by chemical reduction of an aqueous silver salt in the presence of six different stabilising agents. The colloids are then supported on carbon powder (10% loading) for further characterisation and use. The electrocatalytic properties of the Ag_NP/carbon composites towards the dehalogenation of halocompounds are tested by cyclic voltammetry and by preparative electrolysis. The hydrodehalogenation of trichloromethane, extensively studied by this group, is selected as a model reaction, because of its relevance for the detoxification of wastes. The voltammetric characterisation is performed in an aqueous solution, supporting the composites on cavity microelectrodes. Gas-diffusion electrodes (GDE) based on the most promising Ag_NP composite -and, for reference, on a commercial Ag/C oxygen reduction electrocatalystare then tested in an electrolytic process for the progressive conversion of gaseous trichloromethane to less chlorinated compounds, and ultimately to methane.
Nanoparticles in a biological milieu are known to form a sufficiently long-lived and well-organiz... more Nanoparticles in a biological milieu are known to form a sufficiently long-lived and well-organized 'corona' of biomolecules to confer a biological identity to the particle. Because this nanoparticle-biomolecule complex interacts with cells and biological barriers, potentially engaging with different biological pathways, it is important to clarify the presentation of functional biomolecular motifs at its interface. Here, we demonstrate that by using antibody-labelled gold nanoparticles, differential centrifugal sedimentation and various imaging techniques it is possible to identify the spatial location of proteins, their functional motifs and their binding sites. We show that for transferrin-coated polystyrene nanoparticles only a minority of adsorbed proteins exhibit functional motifs and the spatial organization appears random, which is consistent, overall, with a stochastic and irreversible adsorption process. Our methods are applicable to a wide array of nanoparticles and can offer a microscopic molecular description of the biological identity of nanoparticles.
Abstract Gold colloidal nanoparticles stabilized by neutral ligands and peptides/F. Porta, V. Dal... more Abstract Gold colloidal nanoparticles stabilized by neutral ligands and peptides/F. Porta, V. Dal Santo, Z. Krpetic, P. Francescato, G. Speranza.((Intervento presentato al 4.. International Conference on Gold Science, Technology and its Applications: Gold 2006-New Industrial ...
Abstract Silver Gas Diffusion Electrode for Volatile Organic Halocompound Conversion to Hydrocarb... more Abstract Silver Gas Diffusion Electrode for Volatile Organic Halocompound Conversion to Hydrocarbons/S. Rondinini, A. Vertova, F. Porta, A. Minguzzi, G. Aricci, C. Locatelli, Z. Krpetic.-2008. GEI Giornate dell'elettrochimica italiana–ERA Elettrochimica per il recupero ...
... nanoparticles for biological applications, in this PhD project two active components of Aloe ... more ... nanoparticles for biological applications, in this PhD project two active components of Aloe vera, Aloin A and ... Fabris, L., Antonello, S., Armelao, L., Donkers, RL, Polo, F., Toniolo, C., Maran, FJ Am. ... Porta, Francesca; Krpetić, eljka; Prati, Laura; Gaiassi, Aureliano; Scarì, Giorgio. ...
Since alternative splicing patterns are exhibited by most mammalian genes, the functional propert... more Since alternative splicing patterns are exhibited by most mammalian genes, the functional properties of a gene may be changed for therapeutic purposes by nudging splicing from one pattern to another. Splicing to a refractory exon can be enhanced using bifunctional targeted oligonucleotide enhancers of splicing (TOES), which anneal to a target exon and carry additional sequence motifs to recruit activator proteins.
Colloidal nanoparticles designed for the interactions with cells are very small, nanoscale object... more Colloidal nanoparticles designed for the interactions with cells are very small, nanoscale objects usually consisting of inorganic cores and organic shells that are dispersed in a buffer or biological medium. Tuning the material properties the nanoparticles are made from, a number of different properties that can be exploited in specific biological applications are possible, i.e. targeting, labelling, drug delivery, use as diagnostic tools or therapy. For all biological applications of nanoparticles, it is important to understand their interactions with the surrounding biological environment in order to predict their biological impact, in particular when designing the nanoparticles for diagnostic and therapeutic purpose. Due to the high surface-to-volume ratio, the surface of nanomaterials is very reactive. When exposed to biological fluids, the proteins and biomolecules present therein tend to associate with the nanoparticles' surfaces. This phenomenon is defined as biomolecular corona formation. The biomolecular corona plays a key role in the interaction between nanoparticles and biological systems, impacting on how these particles interact with biological systems on a cellular and molecular level. This book chapter describes the nature of the interactions at the bio-nano interface, shows the design strategy of nanoparticles for nanomedicine, and defines the concepts of biomolecular corona and biological identity of nanoparticles. Moreover, it describes the interaction of functionalised nanomaterials with cell organelles and intracellular fate of nanoparticles and it shows therapeutic application of gold nanoparticles as dose enhancers in radiotherapy.
It is demonstrated that a compact monolayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine adsorbed ... more It is demonstrated that a compact monolayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine adsorbed to a hanging mercury drop electrode can serve as a simple electrochemical model system to study biomembrane penetration by gold nanoparticles. The hydrogen redoxchemistry characteristic of ligand-stabilized gold nanoparticles in molecularly close contact with a mercury electrode is used as an indicator of membrane penetration. Results for water-dispersible gold nanoparticles of two different sizes are reported, and comparisons are made with the cellular uptake of the same preparations of nanoparticles by a common human fibroblast cell line. The experimental system described here can be used to study physicochemical aspects of membrane penetration in the absence of complex biological mechanisms, and it could also be a starting point for the development of a test bed for the toxicity of nanomaterials.
Angewandte Chemie (International ed. in English), Jan 19, 2015
The exploration of the genetic information carried by DNA has become a major scientific challenge... more The exploration of the genetic information carried by DNA has become a major scientific challenge. Routine DNA analysis, such as PCR, still suffers from important intrinsic limitations. Surface-enhanced Raman spectroscopy (SERS) has emerged as an outstanding opportunity for the development of DNA analysis, but its application to duplexes (dsDNA) has been largely hampered by reproducibility and/or sensitivity issues. A simple strategy is presented to perform ultrasensitive direct label-free analysis of unmodified dsDNA with the means of SERS by using positively charged silver colloids. Electrostatic adhesion of DNA promotes nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at nanogram level. As potential applications, we report the quantitative recognition of hybridization events as well as the first examples of SERS recognition of single base mismatches and base methylations (5-methylated cytosine and N6-methylated Adenine) in duplexes.
Here we report on the design, synthesis and application of small, highly bright, star-shaped SERS... more Here we report on the design, synthesis and application of small, highly bright, star-shaped SERS encoded single nanoparticles with the ability of providing an optical signal upon excitation with near infrared light. These particles are colloidally stable, fully biocompatible and can be internalized into living cells for intracellular imaging.
Gold nanoparticles of two different sizes stabilized by a 15-mer peptide ligand specifically desi... more Gold nanoparticles of two different sizes stabilized by a 15-mer peptide ligand specifically designed for this purpose have been prepared in aqueous solution and characterized by UV-vis spectroscopy and TEM. The presence of the ligand and its binding mode to the particles via its four cystein thiols is evidenced by FTIR and NMR spectroscopy. Biotinylation of the particles via binding to a freely accessible lysine residue is demonstrated.
A preliminary investigation on a new class on electrocatalytic materials for the electroreduction... more A preliminary investigation on a new class on electrocatalytic materials for the electroreduction of organic halides is presented and discussed. The electrocatalysts are based on silver nanoparticles (Ag_NP), ad hoc synthesised by chemical reduction of an aqueous silver salt in the presence of six different stabilising agents. The colloids are then supported on carbon powder (10% loading) for further characterisation and use. The electrocatalytic properties of the Ag_NP/carbon composites towards the dehalogenation of halocompounds are tested by cyclic voltammetry and by preparative electrolysis. The hydrodehalogenation of trichloromethane, extensively studied by this group, is selected as a model reaction, because of its relevance for the detoxification of wastes. The voltammetric characterisation is performed in an aqueous solution, supporting the composites on cavity microelectrodes. Gas-diffusion electrodes (GDE) based on the most promising Ag_NP composite -and, for reference, on a commercial Ag/C oxygen reduction electrocatalystare then tested in an electrolytic process for the progressive conversion of gaseous trichloromethane to less chlorinated compounds, and ultimately to methane.
Nanoparticles in a biological milieu are known to form a sufficiently long-lived and well-organiz... more Nanoparticles in a biological milieu are known to form a sufficiently long-lived and well-organized 'corona' of biomolecules to confer a biological identity to the particle. Because this nanoparticle-biomolecule complex interacts with cells and biological barriers, potentially engaging with different biological pathways, it is important to clarify the presentation of functional biomolecular motifs at its interface. Here, we demonstrate that by using antibody-labelled gold nanoparticles, differential centrifugal sedimentation and various imaging techniques it is possible to identify the spatial location of proteins, their functional motifs and their binding sites. We show that for transferrin-coated polystyrene nanoparticles only a minority of adsorbed proteins exhibit functional motifs and the spatial organization appears random, which is consistent, overall, with a stochastic and irreversible adsorption process. Our methods are applicable to a wide array of nanoparticles and can offer a microscopic molecular description of the biological identity of nanoparticles.
Abstract Gold colloidal nanoparticles stabilized by neutral ligands and peptides/F. Porta, V. Dal... more Abstract Gold colloidal nanoparticles stabilized by neutral ligands and peptides/F. Porta, V. Dal Santo, Z. Krpetic, P. Francescato, G. Speranza.((Intervento presentato al 4.. International Conference on Gold Science, Technology and its Applications: Gold 2006-New Industrial ...
Abstract Silver Gas Diffusion Electrode for Volatile Organic Halocompound Conversion to Hydrocarb... more Abstract Silver Gas Diffusion Electrode for Volatile Organic Halocompound Conversion to Hydrocarbons/S. Rondinini, A. Vertova, F. Porta, A. Minguzzi, G. Aricci, C. Locatelli, Z. Krpetic.-2008. GEI Giornate dell'elettrochimica italiana–ERA Elettrochimica per il recupero ...
... nanoparticles for biological applications, in this PhD project two active components of Aloe ... more ... nanoparticles for biological applications, in this PhD project two active components of Aloe vera, Aloin A and ... Fabris, L., Antonello, S., Armelao, L., Donkers, RL, Polo, F., Toniolo, C., Maran, FJ Am. ... Porta, Francesca; Krpetić, eljka; Prati, Laura; Gaiassi, Aureliano; Scarì, Giorgio. ...
Since alternative splicing patterns are exhibited by most mammalian genes, the functional propert... more Since alternative splicing patterns are exhibited by most mammalian genes, the functional properties of a gene may be changed for therapeutic purposes by nudging splicing from one pattern to another. Splicing to a refractory exon can be enhanced using bifunctional targeted oligonucleotide enhancers of splicing (TOES), which anneal to a target exon and carry additional sequence motifs to recruit activator proteins.
Colloidal nanoparticles designed for the interactions with cells are very small, nanoscale object... more Colloidal nanoparticles designed for the interactions with cells are very small, nanoscale objects usually consisting of inorganic cores and organic shells that are dispersed in a buffer or biological medium. Tuning the material properties the nanoparticles are made from, a number of different properties that can be exploited in specific biological applications are possible, i.e. targeting, labelling, drug delivery, use as diagnostic tools or therapy. For all biological applications of nanoparticles, it is important to understand their interactions with the surrounding biological environment in order to predict their biological impact, in particular when designing the nanoparticles for diagnostic and therapeutic purpose. Due to the high surface-to-volume ratio, the surface of nanomaterials is very reactive. When exposed to biological fluids, the proteins and biomolecules present therein tend to associate with the nanoparticles' surfaces. This phenomenon is defined as biomolecular corona formation. The biomolecular corona plays a key role in the interaction between nanoparticles and biological systems, impacting on how these particles interact with biological systems on a cellular and molecular level. This book chapter describes the nature of the interactions at the bio-nano interface, shows the design strategy of nanoparticles for nanomedicine, and defines the concepts of biomolecular corona and biological identity of nanoparticles. Moreover, it describes the interaction of functionalised nanomaterials with cell organelles and intracellular fate of nanoparticles and it shows therapeutic application of gold nanoparticles as dose enhancers in radiotherapy.
It is demonstrated that a compact monolayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine adsorbed ... more It is demonstrated that a compact monolayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine adsorbed to a hanging mercury drop electrode can serve as a simple electrochemical model system to study biomembrane penetration by gold nanoparticles. The hydrogen redoxchemistry characteristic of ligand-stabilized gold nanoparticles in molecularly close contact with a mercury electrode is used as an indicator of membrane penetration. Results for water-dispersible gold nanoparticles of two different sizes are reported, and comparisons are made with the cellular uptake of the same preparations of nanoparticles by a common human fibroblast cell line. The experimental system described here can be used to study physicochemical aspects of membrane penetration in the absence of complex biological mechanisms, and it could also be a starting point for the development of a test bed for the toxicity of nanomaterials.
Angewandte Chemie (International ed. in English), Jan 19, 2015
The exploration of the genetic information carried by DNA has become a major scientific challenge... more The exploration of the genetic information carried by DNA has become a major scientific challenge. Routine DNA analysis, such as PCR, still suffers from important intrinsic limitations. Surface-enhanced Raman spectroscopy (SERS) has emerged as an outstanding opportunity for the development of DNA analysis, but its application to duplexes (dsDNA) has been largely hampered by reproducibility and/or sensitivity issues. A simple strategy is presented to perform ultrasensitive direct label-free analysis of unmodified dsDNA with the means of SERS by using positively charged silver colloids. Electrostatic adhesion of DNA promotes nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at nanogram level. As potential applications, we report the quantitative recognition of hybridization events as well as the first examples of SERS recognition of single base mismatches and base methylations (5-methylated cytosine and N6-methylated Adenine) in duplexes.
Here we report on the design, synthesis and application of small, highly bright, star-shaped SERS... more Here we report on the design, synthesis and application of small, highly bright, star-shaped SERS encoded single nanoparticles with the ability of providing an optical signal upon excitation with near infrared light. These particles are colloidally stable, fully biocompatible and can be internalized into living cells for intracellular imaging.
Uploads
Papers by Zeljka Krpetic