Hadi Zareie - Academia.edu (original) (raw)

Papers by Hadi Zareie

Artificial cells, nanomedicine, and biotechnology, Jan 27, 2018

This study attemps to develop bacterial detection strategies using bacteriophages and gold nanoro... more This study attemps to develop bacterial detection strategies using bacteriophages and gold nanorods (GNRs) by Raman spectral analysis. Escherichia coli was selected as the target and its specific phage was used as the bioprobe. Target bacteria and phages were propagated/purified by traditional techniques. GNRs were synthesized by using hexadecyltrimethyl ammonium bromide (CTAB) as stabilizer. A two-step detection strategy was applied: Firstly, the target bacteria were interacted with GNRs in suspensions, and then they were dropped onto silica substrates for detection. It was possible to obtain clear surface-enchanced Raman spectroscopy (SERS) peaks of the target bacteria, even without using phages. In the second step, the phage nanoemulsions were droped onto the bacterial-GNRs complexes on those surfaces and time-dependent changes in the Raman spectra were monitored at different time intervals upto 40 min. These results demonstrated that how one can apply phages with plasmonic nanop...

RSC Adv.

Nitrogen-doped graphene (N-graphene) was prepared by exposing the graphene transferred to differe... more Nitrogen-doped graphene (N-graphene) was prepared by exposing the graphene transferred to different substrates to atomic nitrogen plasma.

Biomacromolecules, Jan 25, 2017

PEGylation, covalent attachment of PEG to therapeutic biomolecules, in which suboptimal pharmacok... more PEGylation, covalent attachment of PEG to therapeutic biomolecules, in which suboptimal pharmacokinetic profiles limiting their therapeutic utility are of concern, is a widely applied technology. However, this technology has been challenged by reduced bioactivity of biomolecules upon PEGylation and immunogenicity of PEG triggering immune response and abrogating clinical efficacy, which collectively necessitate development of stealth polymer alternatives. Here we demonstrate that comb-shape poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA), a stealth polymer alternative, has a more compact structure than PEG and self-organize into nanoparticles in a molecular weight dependent manner. Most notably, we show that comb-shape POEGMA promotes significantly higher cellular uptake and exhibits less steric hindrance imposed on the conjugated biomolecule than PEG. Collectively, comb-shape POEGMA offers a versatile alternative to PEG for stealth polymer-biomolecule conjugation app...

RSC Adv., 2015

A simple method is described for synthesizing gold nanorods (GNRs) encapsulated bubbles in a cont... more A simple method is described for synthesizing gold nanorods (GNRs) encapsulated bubbles in a controlled manner.

Biomedical Science and Technology, 1998

Scanning tunneling microscopy (STM) measures quantum tunneling to produce an atomic scale electro... more Scanning tunneling microscopy (STM) measures quantum tunneling to produce an atomic scale electron density image of it surface . STM has become one of the most powerful instruments in surface science studies. Recently we constructed a scanning tunneling microscope and stud led several macromolecules on highly oriented pyrolytic graphite (HOPG) and mica surfaces. We obtained image of human serum albumin . The graphite substrate also were treated by pure nitrogen gas plasma for different periods . The images of both single stranded DNA fragments and DNA double helbc are obtained and their interactions with smaller molecules (e .g., calcium chioride) are also demons-traded.

Smart Structures, Devices, and Systems II, 2005

Nanoscale particles of metals such as gold can interact with light by means of a plasmon resonanc... more Nanoscale particles of metals such as gold can interact with light by means of a plasmon resonance, even though they are much smaller than the wavelengths of visible light. The proportions of light that are absorbed and scattered vary with wavelength. Any light that is absorbed will cause heating of the particles, and this effect may potentially be exploited for solar glazing coatings, nanoscale lithography or medical treatments. The position of maximum absorption of an isolated spherical nanoparticle is 518 nrn, but this may be significantly red-shifted by means of decreasing the symmetry to an prolate spheroid or 'nanorod', or by producing a metal 'nanoshell' on a dielectric core, or by aggregating insulated spherical particles. Absorption peaks in the vicinity of 655 nm for aggregated particles and 780 nm for prolate spheroids are demonstrated here. Absorbed energy is released as heat into the environment of the particles, and will cause a temperature rise within the particle the magnitude of which depends upon the value of the effective heat transfer coefficient between particle and environment. The latter is not known, but we show how highly localized temperature rises of some tens of Celsius might be conceivable in systems illuminated by sunlight.

Smart Structures, Devices, and Systems II, 2005

The possible role of self-assembled monolayers (SAMs) as the dielectric component of nanoscale ca... more The possible role of self-assembled monolayers (SAMs) as the dielectric component of nanoscale capacitors is considered. SAMs of two rather different molecules, a,c:x'-p-xylyldithiol ('XYL') and dodecanedithiol ('C12') were produced on a gold {Ill} substrate, and characterized with respect to their conductivity. The data were fitted with a double tunnel barrier model, in which the two SAMs are primarily differentiated by barrier height and thickness with that of XYL having a thickness of 1.0 nm and a barrier height of 0.78 eV compared to 1.69 nm and 1.39 eV for C12. The remaining parameters of the model were determined by Monte Carlo optimization. Assuming perfect connection of top and bottom electrodes, the leakage current through the XYL at 1 volt is calculated to be 1.4x10 5 A/cm 2 , compared to 2.7x10 4 A/cm 2 through C12. These values are not as low as can be obtained with Si02 of the same thickness. However, SAMs are readily and precisely produced by simple, low temperature processes, a factor which may allow them a niche in the future.

2008 International Conference on Nanoscience and Nanotechnology, 2008

Gold nanoshells have gained attention recently due to their interesting optical properties. In pa... more Gold nanoshells have gained attention recently due to their interesting optical properties. In particular, their spectrally selective extinction has been exploited for experimental therapeutic medical applications, spectral applications and contrast enhancement for analytical techniques (e.g. Surface Enhanced Raman Scattering Spectroscopy, SERSS). Synthesis of hollow Au/Ag alloy particles utilising galvanic replacement are presented. Ag template particles stabilised by the surfactant CTAB (hexadecyltrimethyl ammonium bromide) produce a distinct population of nanorings upon addition of excess HAuCl 4. Nanorings present an interesting particle geometry, with optical properties exhibiting characteristics of nanorods and nanoshells. I.

BioMEMS and Nanotechnology II, 2005

Scanning tunneling microscopy measurements of tunneling through molecules adsorbed on a surface h... more Scanning tunneling microscopy measurements of tunneling through molecules adsorbed on a surface have been simulated using a standard empirical model based upon the Wentzel-Kramer-Brillouin method applied to tunneling through a barrier. The Gaussian noise inherent in these experiments has been added to the model data using a Monte Carlo technique. By generating multiple sets of current-voltage curves and fitting these to the model we have evaluated how reliably barrier height can be determined as a function of noise level. The results suggest that for constant percentage standard deviation in the noise greater than 5% the barrier height cannot be determined reliably. At this level, the standard deviation in the estimate of the barrier height is about 10%. Weighted fits give more reliable estimates of the barrier height. If the height of the tip above the molecule is known, so that the fit is only a single parameter the barrier height can be determined reliably even at percentage noise levels as high as 20%. However, in this case unweighted fits must be used otherwise the estimated value deviates by up to 15% from the true value. Data with constant absolute noise give similar results. The effects of experimental resolution have been evaluated in a similar manner and are shown to have a significant influence on the reliability. At a resolution of about 0.1% of full scale the standard deviation in the estimate of barrier height is only about 2% but increases rapidly to 10% for a resolution of about 1%.

Macromolecules, 2010

ABSTRACT Well-defined reactive polymer scaffolds are useful building blocks for a variety of biom... more ABSTRACT Well-defined reactive polymer scaffolds are useful building blocks for a variety of biomedicine and nanotechnology applications. In this study, we have converted a RAFT-synthesized thiol-functional homopolymer scaffold (poly(pyridyl disulfide ethyl methacrylate), PPDSM) to poly(ethylene glycol) conjugated (PEGylated) nanoparticles via a straightforward approach. Poly(ethylene glycol) (PEG) was grafted to the reduced PPDSM via radical-mediated thiol−ene or Michael additions. The yield of PEG grafting via radical-mediated thiol−ene reaction and Michael addition was 68 ± 2 and 73 ± 1 mol %, respectively, of the total functional groups on the scaffold, as determined by 1H NMR spectroscopy. The grafting yield via Michael addition reactions was non-linearly proportional to the reducing agent concentration used (thus the number of free thiols created on the polymer chain). It was observed by UV−vis spectroscopy that PEG grafting via Michael addition to the PPDSM takes place simultaneously with inter- and intrachain thiol−disulfide exchange reactions. Dynamic light scattering (DLS) measurements of PEG-acrylate (Mn = 2000 g/mol) grafted PPDSM (74 mol % grafting yield) in water showed the presence of particles with an average hydrodynamic diameter of 99 ± 8 nm and polydispersity index (PDI) of 0.22 ± 0.02. Atomic force microscopy (AFM) analysis of the same sample revealed the presence of spherical shape particles. 1H NMR analysis of the same PEG grafted PPDSM nanoparticles in different solvents revealed that the PPDSM backbone in water was surrounded by PEG chains. Overall, the results indicate that simply grafting PEG to PPDSM homopolymer scaffold can be a straightforward route to the generation of nanoparticles with a biocompatible, stealth shell, and the present synthetic approach can be exploited further for the generation of PEGylated functional nanoparticles for potential drug delivery applications.

Progress in Organic Coatings, 2003

A molecular biomimetics approach is presented in developing polypeptide-based coatings for inorga... more A molecular biomimetics approach is presented in developing polypeptide-based coatings for inorganic surfaces. In general, inorganic surface-binding polypeptides are genetically engineered using cell surface and phage display technologies. These peptides contain short amino acid sequences, known to bind specifically to selected inorganics. Based on the sequences of the polypeptides that were recently selected by this (e.g. Au, Pt and Pd) and other groups, one may find certain specificity, e.g. hydrophobic and hydroxyl amino acids, common among noble metal-binders. We show that an engineered gold-binding protein self-assembles onto gold surface forming monomolecular and highly structured crystallographic domains. The protein-based molecular films could provide robust templates for potential utility in practical nanotechnological and bionanotechnological applications.

2006 International Conference on Nanoscience and Nanotechnology, 2006

We present examples of ordered assemblies of organic and biological molecules on gold(111) surfac... more We present examples of ordered assemblies of organic and biological molecules on gold(111) surfaces. The first example shows how control over mono-or multilayer assemblies of 1,4phenylenedimethanthiol can be achieved and monitored. The second example shows how monolayers on gold can be prepared using amine groups to anchor aromatic molecules to the surface. A third example shows how ordered assemblies of geneticallyengineered inorganic-binding polypeptides can be formed on gold surfaces using a 3-repeat, 14 amino acid gold-binding protein (GBP1).

Tissue Engineering, 1998

Poly(d,l)-lactide (PDLLA) homopolymer, with an average molecular weight of 20,000 daltons, was pr... more Poly(d,l)-lactide (PDLLA) homopolymer, with an average molecular weight of 20,000 daltons, was produced by the ring-opening polymerization of d,l-lactide in the presence of SnCl(2).2H(2)O as the catalyst. The PDLLA sponges loaded with chloramphenicol were prepared by a solvent evaporation technique. The drug loadings achieved were 14.84 and 25.23 mg for the PDLLA sponges with 35 and 70 mg total weights, respectively. These sponges were implanted in Wistar rats, and in vivo degradation, drug release, and tissue reactions were followed. The PDLLA sponges carrying no drug degraded with time linearly. Almost 80% of the sponges were degraded in about 180 days. While the drug-loaded PDLLA sponges were degraded much faster in 4 weeks (about 35% of the matrix was degraded), then the degradation slowed down significantly. Drug release from the sponges was parallel to the degradation. Almost 60% of the loaded drug released in 4 weeks. There were no acute inflammatory reactions in the initial period, either for the plain or for the drug-loaded PDLLA sponges. Macrophages and multinuclear giant cells start to appear after 7 days of implantation. The fibroblastic activity also started after the same period. After that, there were decreases in the number of some cells (neutrophils, lymphocytes, and macrophages), while multinuclear giant cells and fibroblastic activities gradually increased. Granulation tissue started at about 1 month, and new connective tissue was gradually formed until 180 days of implantation. There were significant numbers of inflammatory cells after 60 days, which were replaced by fibroblasts after 180 days. There was almost no significant neovascularization after 180 days, but implant fragmentation gradually increased (which slows the degradation) with time. It was concluded that this novel drug release sponge may be safely and effectively used as an active soft tissue-filling material.

The Journal of Physical Chemistry B, 2006

Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold(111) were irradiate... more Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold(111) were irradiated with low-power UV light. Scanning tunnelling microscope images recorded in situ show unusual structural changes. In the case of 2-anthracenethiol, structures measuring 4-7 nm wide and 30-40 nm in length are formed. Images taken ten minutes after irradiation ceased show further surface reorganisation. With 2-naphthalenethiol SAMs, smaller structures form upon irradiation, which subsequently revert to resemble the original structure after time. KEYWORDS (Word Style "BG_Keywords"). If you are submitting your paper to a journal that requires keywords, provide significant keywords to aid the reader in literature retrieval.

Artificial cells, nanomedicine, and biotechnology, Jan 27, 2018

This study attemps to develop bacterial detection strategies using bacteriophages and gold nanoro... more This study attemps to develop bacterial detection strategies using bacteriophages and gold nanorods (GNRs) by Raman spectral analysis. Escherichia coli was selected as the target and its specific phage was used as the bioprobe. Target bacteria and phages were propagated/purified by traditional techniques. GNRs were synthesized by using hexadecyltrimethyl ammonium bromide (CTAB) as stabilizer. A two-step detection strategy was applied: Firstly, the target bacteria were interacted with GNRs in suspensions, and then they were dropped onto silica substrates for detection. It was possible to obtain clear surface-enchanced Raman spectroscopy (SERS) peaks of the target bacteria, even without using phages. In the second step, the phage nanoemulsions were droped onto the bacterial-GNRs complexes on those surfaces and time-dependent changes in the Raman spectra were monitored at different time intervals upto 40 min. These results demonstrated that how one can apply phages with plasmonic nanop...

RSC Adv.

Nitrogen-doped graphene (N-graphene) was prepared by exposing the graphene transferred to differe... more Nitrogen-doped graphene (N-graphene) was prepared by exposing the graphene transferred to different substrates to atomic nitrogen plasma.

Biomacromolecules, Jan 25, 2017

PEGylation, covalent attachment of PEG to therapeutic biomolecules, in which suboptimal pharmacok... more PEGylation, covalent attachment of PEG to therapeutic biomolecules, in which suboptimal pharmacokinetic profiles limiting their therapeutic utility are of concern, is a widely applied technology. However, this technology has been challenged by reduced bioactivity of biomolecules upon PEGylation and immunogenicity of PEG triggering immune response and abrogating clinical efficacy, which collectively necessitate development of stealth polymer alternatives. Here we demonstrate that comb-shape poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA), a stealth polymer alternative, has a more compact structure than PEG and self-organize into nanoparticles in a molecular weight dependent manner. Most notably, we show that comb-shape POEGMA promotes significantly higher cellular uptake and exhibits less steric hindrance imposed on the conjugated biomolecule than PEG. Collectively, comb-shape POEGMA offers a versatile alternative to PEG for stealth polymer-biomolecule conjugation app...

RSC Adv., 2015

A simple method is described for synthesizing gold nanorods (GNRs) encapsulated bubbles in a cont... more A simple method is described for synthesizing gold nanorods (GNRs) encapsulated bubbles in a controlled manner.

Biomedical Science and Technology, 1998

Scanning tunneling microscopy (STM) measures quantum tunneling to produce an atomic scale electro... more Scanning tunneling microscopy (STM) measures quantum tunneling to produce an atomic scale electron density image of it surface . STM has become one of the most powerful instruments in surface science studies. Recently we constructed a scanning tunneling microscope and stud led several macromolecules on highly oriented pyrolytic graphite (HOPG) and mica surfaces. We obtained image of human serum albumin . The graphite substrate also were treated by pure nitrogen gas plasma for different periods . The images of both single stranded DNA fragments and DNA double helbc are obtained and their interactions with smaller molecules (e .g., calcium chioride) are also demons-traded.

Smart Structures, Devices, and Systems II, 2005

Nanoscale particles of metals such as gold can interact with light by means of a plasmon resonanc... more Nanoscale particles of metals such as gold can interact with light by means of a plasmon resonance, even though they are much smaller than the wavelengths of visible light. The proportions of light that are absorbed and scattered vary with wavelength. Any light that is absorbed will cause heating of the particles, and this effect may potentially be exploited for solar glazing coatings, nanoscale lithography or medical treatments. The position of maximum absorption of an isolated spherical nanoparticle is 518 nrn, but this may be significantly red-shifted by means of decreasing the symmetry to an prolate spheroid or 'nanorod', or by producing a metal 'nanoshell' on a dielectric core, or by aggregating insulated spherical particles. Absorption peaks in the vicinity of 655 nm for aggregated particles and 780 nm for prolate spheroids are demonstrated here. Absorbed energy is released as heat into the environment of the particles, and will cause a temperature rise within the particle the magnitude of which depends upon the value of the effective heat transfer coefficient between particle and environment. The latter is not known, but we show how highly localized temperature rises of some tens of Celsius might be conceivable in systems illuminated by sunlight.

Smart Structures, Devices, and Systems II, 2005

The possible role of self-assembled monolayers (SAMs) as the dielectric component of nanoscale ca... more The possible role of self-assembled monolayers (SAMs) as the dielectric component of nanoscale capacitors is considered. SAMs of two rather different molecules, a,c:x'-p-xylyldithiol ('XYL') and dodecanedithiol ('C12') were produced on a gold {Ill} substrate, and characterized with respect to their conductivity. The data were fitted with a double tunnel barrier model, in which the two SAMs are primarily differentiated by barrier height and thickness with that of XYL having a thickness of 1.0 nm and a barrier height of 0.78 eV compared to 1.69 nm and 1.39 eV for C12. The remaining parameters of the model were determined by Monte Carlo optimization. Assuming perfect connection of top and bottom electrodes, the leakage current through the XYL at 1 volt is calculated to be 1.4x10 5 A/cm 2 , compared to 2.7x10 4 A/cm 2 through C12. These values are not as low as can be obtained with Si02 of the same thickness. However, SAMs are readily and precisely produced by simple, low temperature processes, a factor which may allow them a niche in the future.

2008 International Conference on Nanoscience and Nanotechnology, 2008

Gold nanoshells have gained attention recently due to their interesting optical properties. In pa... more Gold nanoshells have gained attention recently due to their interesting optical properties. In particular, their spectrally selective extinction has been exploited for experimental therapeutic medical applications, spectral applications and contrast enhancement for analytical techniques (e.g. Surface Enhanced Raman Scattering Spectroscopy, SERSS). Synthesis of hollow Au/Ag alloy particles utilising galvanic replacement are presented. Ag template particles stabilised by the surfactant CTAB (hexadecyltrimethyl ammonium bromide) produce a distinct population of nanorings upon addition of excess HAuCl 4. Nanorings present an interesting particle geometry, with optical properties exhibiting characteristics of nanorods and nanoshells. I.

BioMEMS and Nanotechnology II, 2005

Scanning tunneling microscopy measurements of tunneling through molecules adsorbed on a surface h... more Scanning tunneling microscopy measurements of tunneling through molecules adsorbed on a surface have been simulated using a standard empirical model based upon the Wentzel-Kramer-Brillouin method applied to tunneling through a barrier. The Gaussian noise inherent in these experiments has been added to the model data using a Monte Carlo technique. By generating multiple sets of current-voltage curves and fitting these to the model we have evaluated how reliably barrier height can be determined as a function of noise level. The results suggest that for constant percentage standard deviation in the noise greater than 5% the barrier height cannot be determined reliably. At this level, the standard deviation in the estimate of the barrier height is about 10%. Weighted fits give more reliable estimates of the barrier height. If the height of the tip above the molecule is known, so that the fit is only a single parameter the barrier height can be determined reliably even at percentage noise levels as high as 20%. However, in this case unweighted fits must be used otherwise the estimated value deviates by up to 15% from the true value. Data with constant absolute noise give similar results. The effects of experimental resolution have been evaluated in a similar manner and are shown to have a significant influence on the reliability. At a resolution of about 0.1% of full scale the standard deviation in the estimate of barrier height is only about 2% but increases rapidly to 10% for a resolution of about 1%.

Macromolecules, 2010

ABSTRACT Well-defined reactive polymer scaffolds are useful building blocks for a variety of biom... more ABSTRACT Well-defined reactive polymer scaffolds are useful building blocks for a variety of biomedicine and nanotechnology applications. In this study, we have converted a RAFT-synthesized thiol-functional homopolymer scaffold (poly(pyridyl disulfide ethyl methacrylate), PPDSM) to poly(ethylene glycol) conjugated (PEGylated) nanoparticles via a straightforward approach. Poly(ethylene glycol) (PEG) was grafted to the reduced PPDSM via radical-mediated thiol−ene or Michael additions. The yield of PEG grafting via radical-mediated thiol−ene reaction and Michael addition was 68 ± 2 and 73 ± 1 mol %, respectively, of the total functional groups on the scaffold, as determined by 1H NMR spectroscopy. The grafting yield via Michael addition reactions was non-linearly proportional to the reducing agent concentration used (thus the number of free thiols created on the polymer chain). It was observed by UV−vis spectroscopy that PEG grafting via Michael addition to the PPDSM takes place simultaneously with inter- and intrachain thiol−disulfide exchange reactions. Dynamic light scattering (DLS) measurements of PEG-acrylate (Mn = 2000 g/mol) grafted PPDSM (74 mol % grafting yield) in water showed the presence of particles with an average hydrodynamic diameter of 99 ± 8 nm and polydispersity index (PDI) of 0.22 ± 0.02. Atomic force microscopy (AFM) analysis of the same sample revealed the presence of spherical shape particles. 1H NMR analysis of the same PEG grafted PPDSM nanoparticles in different solvents revealed that the PPDSM backbone in water was surrounded by PEG chains. Overall, the results indicate that simply grafting PEG to PPDSM homopolymer scaffold can be a straightforward route to the generation of nanoparticles with a biocompatible, stealth shell, and the present synthetic approach can be exploited further for the generation of PEGylated functional nanoparticles for potential drug delivery applications.

Progress in Organic Coatings, 2003

A molecular biomimetics approach is presented in developing polypeptide-based coatings for inorga... more A molecular biomimetics approach is presented in developing polypeptide-based coatings for inorganic surfaces. In general, inorganic surface-binding polypeptides are genetically engineered using cell surface and phage display technologies. These peptides contain short amino acid sequences, known to bind specifically to selected inorganics. Based on the sequences of the polypeptides that were recently selected by this (e.g. Au, Pt and Pd) and other groups, one may find certain specificity, e.g. hydrophobic and hydroxyl amino acids, common among noble metal-binders. We show that an engineered gold-binding protein self-assembles onto gold surface forming monomolecular and highly structured crystallographic domains. The protein-based molecular films could provide robust templates for potential utility in practical nanotechnological and bionanotechnological applications.

2006 International Conference on Nanoscience and Nanotechnology, 2006

We present examples of ordered assemblies of organic and biological molecules on gold(111) surfac... more We present examples of ordered assemblies of organic and biological molecules on gold(111) surfaces. The first example shows how control over mono-or multilayer assemblies of 1,4phenylenedimethanthiol can be achieved and monitored. The second example shows how monolayers on gold can be prepared using amine groups to anchor aromatic molecules to the surface. A third example shows how ordered assemblies of geneticallyengineered inorganic-binding polypeptides can be formed on gold surfaces using a 3-repeat, 14 amino acid gold-binding protein (GBP1).

Tissue Engineering, 1998

Poly(d,l)-lactide (PDLLA) homopolymer, with an average molecular weight of 20,000 daltons, was pr... more Poly(d,l)-lactide (PDLLA) homopolymer, with an average molecular weight of 20,000 daltons, was produced by the ring-opening polymerization of d,l-lactide in the presence of SnCl(2).2H(2)O as the catalyst. The PDLLA sponges loaded with chloramphenicol were prepared by a solvent evaporation technique. The drug loadings achieved were 14.84 and 25.23 mg for the PDLLA sponges with 35 and 70 mg total weights, respectively. These sponges were implanted in Wistar rats, and in vivo degradation, drug release, and tissue reactions were followed. The PDLLA sponges carrying no drug degraded with time linearly. Almost 80% of the sponges were degraded in about 180 days. While the drug-loaded PDLLA sponges were degraded much faster in 4 weeks (about 35% of the matrix was degraded), then the degradation slowed down significantly. Drug release from the sponges was parallel to the degradation. Almost 60% of the loaded drug released in 4 weeks. There were no acute inflammatory reactions in the initial period, either for the plain or for the drug-loaded PDLLA sponges. Macrophages and multinuclear giant cells start to appear after 7 days of implantation. The fibroblastic activity also started after the same period. After that, there were decreases in the number of some cells (neutrophils, lymphocytes, and macrophages), while multinuclear giant cells and fibroblastic activities gradually increased. Granulation tissue started at about 1 month, and new connective tissue was gradually formed until 180 days of implantation. There were significant numbers of inflammatory cells after 60 days, which were replaced by fibroblasts after 180 days. There was almost no significant neovascularization after 180 days, but implant fragmentation gradually increased (which slows the degradation) with time. It was concluded that this novel drug release sponge may be safely and effectively used as an active soft tissue-filling material.

The Journal of Physical Chemistry B, 2006

Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold(111) were irradiate... more Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold(111) were irradiated with low-power UV light. Scanning tunnelling microscope images recorded in situ show unusual structural changes. In the case of 2-anthracenethiol, structures measuring 4-7 nm wide and 30-40 nm in length are formed. Images taken ten minutes after irradiation ceased show further surface reorganisation. With 2-naphthalenethiol SAMs, smaller structures form upon irradiation, which subsequently revert to resemble the original structure after time. KEYWORDS (Word Style "BG_Keywords"). If you are submitting your paper to a journal that requires keywords, provide significant keywords to aid the reader in literature retrieval.