Michele Laus | Università degli Studi del Piemonte Orientale "Amedeo Avogadro" (original) (raw)
Papers by Michele Laus
The Journal of Physical Chemistry C, Jul 25, 2013
Issues encountered in the depth profiling analysis, by secondary ion mass spectrometry (SIMS), of... more Issues encountered in the depth profiling analysis, by secondary ion mass spectrometry (SIMS), of structured nanoparticles based on Stober silica are studied. The main issue concerns melting under the impact of the primary ions designed to sputter the sample for the profiling. The nanoparticles chosen are deliberately large to minimize the effects of heating. The nanoparticles used are either of a core of Au encased in a shell of SiO 2 or a core of SiO 2 with a thin layer of very small Ag nanoparticles, also encased in SiO 2 , both the final particles being ∼200 nm in diameter and being characterized and designed for optical purposes. The SIMS depth profiles are conducted with Ar n + and C 60 + cluster primary ions that generate very high sputtering yields and so may be expected to have a low energy deposition per unit of layer removal and per emitted signal ion. They are also conducted with ultralow energy Cs + and O 2 + primary ions that have an intrinsically low energy deposition per impacting ion. In all cases, the interpretation of the SIMS depth profiles shows that melting occurs, although it is likely that with ultralow energy Cs + this effect is minimized. The Au core may be profiled without melting. These results are confirmed by scanning electron microscope studies and show that meaningful SIMS depth profiling of nanoparticles may only be possible if an efficient heat sinking method is available.
Inorganica Chimica Acta, 2009
Polymer-based, covalently linked drug-delivery systems have been shown to improve the therapeutic... more Polymer-based, covalently linked drug-delivery systems have been shown to improve the therapeutic index of effective but toxic anticancer agents, such as cisplatin, by exploiting the peculiar features of tumour blood and lymphatic circulation. In the present study, positively charged poly( ...
Physica Status Solidi, 2011
... Microeng. 18, 064012 (2008). [11] CT Black, KW Guarini, G. Breyta, MC Colburn, R. Ruiz, RL Sa... more ... Microeng. 18, 064012 (2008). [11] CT Black, KW Guarini, G. Breyta, MC Colburn, R. Ruiz, RL Sandstrom, EM Sikorski, and Y. Zhang, J. Vac. Sci. Technol. ... 4 L. Boarino et al.: Macro and quasi-mesoporous silicon by self-assembling and MAE physica ssp status solidi a ...
Nucleosides Nucleotides, Oct 4, 2006
The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reve... more The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reversibly bound to new polymeric nanoparticles in HL-60 cellular system have been found to increase by 50 folds if compared with the free ODN. An initial single dose (320 nM) of the nanoparticle bound unmodified antimyb ODN has been able to specifically inhibit HL-60 leukemia cell proliferation for at least 8 days.
Psst 2014 Home Page, Jan 23, 2014
Thanks to diblock copolymers self-assembly, it is possible to propagate periodic polymeric nanost... more Thanks to diblock copolymers self-assembly, it is possible to propagate periodic polymeric nanostructures on large area to silicon dioxide and silicon by Reactive Ion Etching or Metal Assisted Etching, obtaining ordered mesoporous silicon with pore size ranging from 50 to 10 nanometers an less. The two different propagation methods are compared in this work.
Journal of Inorganic Biochemistry, 2015
Multilayer fluorescent nonporous silica nanoparticles (SNPs) with an external shell containing pr... more Multilayer fluorescent nonporous silica nanoparticles (SNPs) with an external shell containing primary amino groups were used as delivery systems for Pt(IV) candidate antitumor prodrugs. Spherical SNPs of three different sizes (diameter around 120, 100, and 50 nm) were loaded with two different complexes, namely (OC-6-33)diamminebis(4-carboxybutanoato)dichloridoplatinum(IV) (1) and (OC-6-44)-diammine(4-carboxybutanoato) dichloridoethanolatoplatinum(IV) (2), through the formation of amide bonds between the pendant amino groups on SNPs and the free carboxylic groups of the complexes. Complex 1 proved to cause heavy and irreversible agglomeration of SNPs; likely, the presence of two reactive carboxylic functionalities induces the formation of cross-links between the amino-decorated SNPs. On the contrary, the conjugates 2-SNP, obtained from the monofunctionalized 2, afforded aqueous nano-suspensions reasonably stable toward aggregation. These solutions showed a limited Pt release in water in the absence of any reducing agents, mainly in form of a Pt(IV) derivative generated by the hydrolysis of the Si-O-Si bond of the functionalized arms attached to silica. In the presence of ascorbic acid, the reduction Pt(IV) → Pt(II) caused the release of the active metabolite cisplatin. Conjugates 2-SNP exhibited much better antiproliferative activity on the Pt-sensitive ovarian A2780 cell line than parent cisplatin and free 2, due to their more efficient cellular uptake.
Polymer News, 2005
ABSTRACT The controlled (or “living”) radical polymerization techniques, nitroxide-mediated radic... more ABSTRACT The controlled (or “living”) radical polymerization techniques, nitroxide-mediated radical polymerization, atom transfer radical polymerization, reversible addition fragmentation chain-transfer polymerization, methods based on iniferters are reviewed. For each technique a brief historical profile is given, and the mechanism, features, and applications are discussed. A few examples of the macromolecular architectures that can be achieved through these techniques are reported and some implementations and developments from industrial companies are presented.
Handbook of Liquid Crystals
Progress in Biotechnology, 1996
A commercial pectinase, immobilised on appropriately functionalised γ-alumina spheres, was loaded... more A commercial pectinase, immobilised on appropriately functionalised γ-alumina spheres, was loaded in a packed bed reactor and employed to depolymerise the pectin contained in a model solution and in the apple juice. The activity of the immobilized enzyme was tested in several batch reactions and compared with the one of the free enzyme. A successful apple juice depectinisation was obtained
ACS Photonics, 2015
We establish a new strategy to achieve fast and responsive hybrid distributed Bragg reflectors fo... more We establish a new strategy to achieve fast and responsive hybrid distributed Bragg reflectors for environmental vapor sensing. We fabricated easily processable zinc oxide− polystyrene nanocomposites to grow high quality multilayers with large gas permeability and dielectric contrast, which enable fast and sensitive detection of vapor analytes. Multilayers fabricated by simple spin-coating of the nanocomposite and cellulose acetate show a 10fold enhancement of the optical response to toluene exposure compared to reference distributed Bragg reflectors built with bare polystyrene.
Journal de Physique II, 1996
Journal of controlled release : official journal of the Controlled Release Society, Jan 3, 2005
Journal of materials science. Materials in medicine, 1999
Hydrogels are three-dimensional polymeric networks very similar to biological tissues and potenti... more Hydrogels are three-dimensional polymeric networks very similar to biological tissues and potentially useful as drug delivery systems. Poly(vinyl alcohol)-based hydrogels containing different amounts of dextran or chitosan were prepared using the freezing-thawing method. Repeated freezing-thawing cycles of a poly(vinyl alcohol) (PVA) aqueous solution lead to the formation of crystallites which act as cross-linking sites, and a hydrogel with a high capacity to swell is obtained. The effects of the two different polysaccharides on the properties of the obtained materials were investigated by differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy. In addition the release with time of poly(vinyl alcohol) in aqueous medium, was monitored and evaluated. On the basis of the obtained results it seems that the presence of dextran favors the crystallization process of PVA, allowing the formation of a more ordered and homogeneous structure. Instead, chi...
Physical review. E, Statistical, nonlinear, and soft matter physics, 2001
We report the first study by inelastic (INS) and quasielastic neutron scattering of photoinduced ... more We report the first study by inelastic (INS) and quasielastic neutron scattering of photoinduced changes in the reorientational and vibrational dynamics of a liquid crystalline side chain polymer. We use the cis-trans photoisomerization transition to take the system out of equilibrium and determine the quasielastic (QE) and inelastic scattering laws on two distinct time windows, corresponding to the time-of-flight (IN6) and backscattering (IN16) spectrometers at Institut Laue Langevin (ILL) (Grenoble). Our investigation was focused on the dynamics of the coupling between the mesogenic side chains and the polymeric main chain, which is connected to the extensive optical writing and memory effects that have been demonstrated in this complex material. We report data on the QE broadening and Debye-Waller factors, as a function of temperature across the glass transition (T(g)=293 K). We also studied the dynamical coupling of side and main chains. We report photoinduced changes on the sta...
Platinum and Other Heavy Metal Compounds in Cancer Chemotherapy, 2009
Abstract The development of synthetic polymer drug-delivery systems is a promising strategy to im... more Abstract The development of synthetic polymer drug-delivery systems is a promising strategy to improve the therapeutic index of effective but highly toxic anti-cancer agents, such as cisplatin, by taking advantage of the peculiar characteristics of tumor blood and lymphatic ...
Nucleosides and Nucleotides, 1999
The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reve... more The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reversibly bound to new polymeric nanoparticles in HL-60 cellular system have been found to increase by 50 folds if compared with the free ODN. An initial single dose (320 nM) of the nanoparticle bound unmodified antimyb ODN has been able to specifically inhibit HL-60 leukemia cell proliferation for at least 8 days.
SPIE Proceedings, 2013
ABSTRACT Laser-matter interaction is a unique and simple approach to structure materials or local... more ABSTRACT Laser-matter interaction is a unique and simple approach to structure materials or locally modify their properties at the micro and nanoscale level. Playing with the pulse duration and the laser wavelength, a broad range of materials and applications can be addressed. Direct irradiation of surfaces with laser beam through a standard optical beam setup allows an easy and fast structuring of these surfaces in the range of few micrometers. However, the irradiation of materials through an array of dielectric nanospheres provides a unique opportunity to break the diffraction limit and to realize structures in the range of hundred of nanometers. This simple, fast and low-cost near-field nanolithography technique is presented and discussed, as well as its great potential. The theoretical aspects of the near-field enhancement effects underneath the particles have been studied with a simple model based on the Mie theory. A commercial FDTD software has also been used to study the influence of the substrate and the surrounding media, on the energy profile of the photonic jet generated under the sphere. A specific study has been dedicated to the influence of the dispersion of the sphere diameter on the morphology of the ablation craters. This technique has been used for patterning bi-layer substrates. The process leads to the formation of a nanoporous membrane which has been used to realize an array of gold nanodots on silicon. We have also associated the Laser-Induced Forward Transfer (LIFT) process with the near-field nanolithography to print, in a single laser shot, an array of metallic nanobumps.
The Journal of Physical Chemistry C, Jul 25, 2013
Issues encountered in the depth profiling analysis, by secondary ion mass spectrometry (SIMS), of... more Issues encountered in the depth profiling analysis, by secondary ion mass spectrometry (SIMS), of structured nanoparticles based on Stober silica are studied. The main issue concerns melting under the impact of the primary ions designed to sputter the sample for the profiling. The nanoparticles chosen are deliberately large to minimize the effects of heating. The nanoparticles used are either of a core of Au encased in a shell of SiO 2 or a core of SiO 2 with a thin layer of very small Ag nanoparticles, also encased in SiO 2 , both the final particles being ∼200 nm in diameter and being characterized and designed for optical purposes. The SIMS depth profiles are conducted with Ar n + and C 60 + cluster primary ions that generate very high sputtering yields and so may be expected to have a low energy deposition per unit of layer removal and per emitted signal ion. They are also conducted with ultralow energy Cs + and O 2 + primary ions that have an intrinsically low energy deposition per impacting ion. In all cases, the interpretation of the SIMS depth profiles shows that melting occurs, although it is likely that with ultralow energy Cs + this effect is minimized. The Au core may be profiled without melting. These results are confirmed by scanning electron microscope studies and show that meaningful SIMS depth profiling of nanoparticles may only be possible if an efficient heat sinking method is available.
Inorganica Chimica Acta, 2009
Polymer-based, covalently linked drug-delivery systems have been shown to improve the therapeutic... more Polymer-based, covalently linked drug-delivery systems have been shown to improve the therapeutic index of effective but toxic anticancer agents, such as cisplatin, by exploiting the peculiar features of tumour blood and lymphatic circulation. In the present study, positively charged poly( ...
Physica Status Solidi, 2011
... Microeng. 18, 064012 (2008). [11] CT Black, KW Guarini, G. Breyta, MC Colburn, R. Ruiz, RL Sa... more ... Microeng. 18, 064012 (2008). [11] CT Black, KW Guarini, G. Breyta, MC Colburn, R. Ruiz, RL Sandstrom, EM Sikorski, and Y. Zhang, J. Vac. Sci. Technol. ... 4 L. Boarino et al.: Macro and quasi-mesoporous silicon by self-assembling and MAE physica ssp status solidi a ...
Nucleosides Nucleotides, Oct 4, 2006
The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reve... more The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reversibly bound to new polymeric nanoparticles in HL-60 cellular system have been found to increase by 50 folds if compared with the free ODN. An initial single dose (320 nM) of the nanoparticle bound unmodified antimyb ODN has been able to specifically inhibit HL-60 leukemia cell proliferation for at least 8 days.
Psst 2014 Home Page, Jan 23, 2014
Thanks to diblock copolymers self-assembly, it is possible to propagate periodic polymeric nanost... more Thanks to diblock copolymers self-assembly, it is possible to propagate periodic polymeric nanostructures on large area to silicon dioxide and silicon by Reactive Ion Etching or Metal Assisted Etching, obtaining ordered mesoporous silicon with pore size ranging from 50 to 10 nanometers an less. The two different propagation methods are compared in this work.
Journal of Inorganic Biochemistry, 2015
Multilayer fluorescent nonporous silica nanoparticles (SNPs) with an external shell containing pr... more Multilayer fluorescent nonporous silica nanoparticles (SNPs) with an external shell containing primary amino groups were used as delivery systems for Pt(IV) candidate antitumor prodrugs. Spherical SNPs of three different sizes (diameter around 120, 100, and 50 nm) were loaded with two different complexes, namely (OC-6-33)diamminebis(4-carboxybutanoato)dichloridoplatinum(IV) (1) and (OC-6-44)-diammine(4-carboxybutanoato) dichloridoethanolatoplatinum(IV) (2), through the formation of amide bonds between the pendant amino groups on SNPs and the free carboxylic groups of the complexes. Complex 1 proved to cause heavy and irreversible agglomeration of SNPs; likely, the presence of two reactive carboxylic functionalities induces the formation of cross-links between the amino-decorated SNPs. On the contrary, the conjugates 2-SNP, obtained from the monofunctionalized 2, afforded aqueous nano-suspensions reasonably stable toward aggregation. These solutions showed a limited Pt release in water in the absence of any reducing agents, mainly in form of a Pt(IV) derivative generated by the hydrolysis of the Si-O-Si bond of the functionalized arms attached to silica. In the presence of ascorbic acid, the reduction Pt(IV) → Pt(II) caused the release of the active metabolite cisplatin. Conjugates 2-SNP exhibited much better antiproliferative activity on the Pt-sensitive ovarian A2780 cell line than parent cisplatin and free 2, due to their more efficient cellular uptake.
Polymer News, 2005
ABSTRACT The controlled (or “living”) radical polymerization techniques, nitroxide-mediated radic... more ABSTRACT The controlled (or “living”) radical polymerization techniques, nitroxide-mediated radical polymerization, atom transfer radical polymerization, reversible addition fragmentation chain-transfer polymerization, methods based on iniferters are reviewed. For each technique a brief historical profile is given, and the mechanism, features, and applications are discussed. A few examples of the macromolecular architectures that can be achieved through these techniques are reported and some implementations and developments from industrial companies are presented.
Handbook of Liquid Crystals
Progress in Biotechnology, 1996
A commercial pectinase, immobilised on appropriately functionalised γ-alumina spheres, was loaded... more A commercial pectinase, immobilised on appropriately functionalised γ-alumina spheres, was loaded in a packed bed reactor and employed to depolymerise the pectin contained in a model solution and in the apple juice. The activity of the immobilized enzyme was tested in several batch reactions and compared with the one of the free enzyme. A successful apple juice depectinisation was obtained
ACS Photonics, 2015
We establish a new strategy to achieve fast and responsive hybrid distributed Bragg reflectors fo... more We establish a new strategy to achieve fast and responsive hybrid distributed Bragg reflectors for environmental vapor sensing. We fabricated easily processable zinc oxide− polystyrene nanocomposites to grow high quality multilayers with large gas permeability and dielectric contrast, which enable fast and sensitive detection of vapor analytes. Multilayers fabricated by simple spin-coating of the nanocomposite and cellulose acetate show a 10fold enhancement of the optical response to toluene exposure compared to reference distributed Bragg reflectors built with bare polystyrene.
Journal de Physique II, 1996
Journal of controlled release : official journal of the Controlled Release Society, Jan 3, 2005
Journal of materials science. Materials in medicine, 1999
Hydrogels are three-dimensional polymeric networks very similar to biological tissues and potenti... more Hydrogels are three-dimensional polymeric networks very similar to biological tissues and potentially useful as drug delivery systems. Poly(vinyl alcohol)-based hydrogels containing different amounts of dextran or chitosan were prepared using the freezing-thawing method. Repeated freezing-thawing cycles of a poly(vinyl alcohol) (PVA) aqueous solution lead to the formation of crystallites which act as cross-linking sites, and a hydrogel with a high capacity to swell is obtained. The effects of the two different polysaccharides on the properties of the obtained materials were investigated by differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy. In addition the release with time of poly(vinyl alcohol) in aqueous medium, was monitored and evaluated. On the basis of the obtained results it seems that the presence of dextran favors the crystallization process of PVA, allowing the formation of a more ordered and homogeneous structure. Instead, chi...
Physical review. E, Statistical, nonlinear, and soft matter physics, 2001
We report the first study by inelastic (INS) and quasielastic neutron scattering of photoinduced ... more We report the first study by inelastic (INS) and quasielastic neutron scattering of photoinduced changes in the reorientational and vibrational dynamics of a liquid crystalline side chain polymer. We use the cis-trans photoisomerization transition to take the system out of equilibrium and determine the quasielastic (QE) and inelastic scattering laws on two distinct time windows, corresponding to the time-of-flight (IN6) and backscattering (IN16) spectrometers at Institut Laue Langevin (ILL) (Grenoble). Our investigation was focused on the dynamics of the coupling between the mesogenic side chains and the polymeric main chain, which is connected to the extensive optical writing and memory effects that have been demonstrated in this complex material. We report data on the QE broadening and Debye-Waller factors, as a function of temperature across the glass transition (T(g)=293 K). We also studied the dynamical coupling of side and main chains. We report photoinduced changes on the sta...
Platinum and Other Heavy Metal Compounds in Cancer Chemotherapy, 2009
Abstract The development of synthetic polymer drug-delivery systems is a promising strategy to im... more Abstract The development of synthetic polymer drug-delivery systems is a promising strategy to improve the therapeutic index of effective but highly toxic anti-cancer agents, such as cisplatin, by taking advantage of the peculiar characteristics of tumor blood and lymphatic ...
Nucleosides and Nucleotides, 1999
The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reve... more The cellular uptake and the inhibitory effect of c-myb unmodified antisense oligonucleotides reversibly bound to new polymeric nanoparticles in HL-60 cellular system have been found to increase by 50 folds if compared with the free ODN. An initial single dose (320 nM) of the nanoparticle bound unmodified antimyb ODN has been able to specifically inhibit HL-60 leukemia cell proliferation for at least 8 days.
SPIE Proceedings, 2013
ABSTRACT Laser-matter interaction is a unique and simple approach to structure materials or local... more ABSTRACT Laser-matter interaction is a unique and simple approach to structure materials or locally modify their properties at the micro and nanoscale level. Playing with the pulse duration and the laser wavelength, a broad range of materials and applications can be addressed. Direct irradiation of surfaces with laser beam through a standard optical beam setup allows an easy and fast structuring of these surfaces in the range of few micrometers. However, the irradiation of materials through an array of dielectric nanospheres provides a unique opportunity to break the diffraction limit and to realize structures in the range of hundred of nanometers. This simple, fast and low-cost near-field nanolithography technique is presented and discussed, as well as its great potential. The theoretical aspects of the near-field enhancement effects underneath the particles have been studied with a simple model based on the Mie theory. A commercial FDTD software has also been used to study the influence of the substrate and the surrounding media, on the energy profile of the photonic jet generated under the sphere. A specific study has been dedicated to the influence of the dispersion of the sphere diameter on the morphology of the ablation craters. This technique has been used for patterning bi-layer substrates. The process leads to the formation of a nanoporous membrane which has been used to realize an array of gold nanodots on silicon. We have also associated the Laser-Induced Forward Transfer (LIFT) process with the near-field nanolithography to print, in a single laser shot, an array of metallic nanobumps.