Papers by Virgilio Brunetti
Abstract Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine s... more Abstract Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine since understanding the bases of such interaction represents a crucial aspect in the design of safe implant devices with intrinsic antibacterial characteristics. In this framework, we investigated the effects of nanostructured metal substrates on Escherichia coli adhesion and adaptation in order to understand the bio-molecular dynamics ruling the interactions at the interface.
The development of fluorescent biolabels for specific targeting and controlled drug release is of... more The development of fluorescent biolabels for specific targeting and controlled drug release is of paramount importance in biological applications due to their potential in the generation of novel tools for simultaneous diagnosis and treatment of diseases. Dopamine is a neurotransmitter involved in several neurological diseases, such as Parkinson's disease and attention deficit hyperactivity disorder (ADHD), and the controlled delivery of its agonists already proved to have beneficial effects both in vitro and in vivo.
Abstract We describe the design and optimization of a reliable strategy that combines self-assemb... more Abstract We describe the design and optimization of a reliable strategy that combines self-assembly and lithographic techniques, leading to very precise micro-/nanopositioning of biomolecules for the realization of micro-and nanoarrays of functional DNA and antibodies.
ABSTRACT We show that water soluble InP/ZnS core/shell QDs are a safer alternative to CdSe/ZnS QD... more ABSTRACT We show that water soluble InP/ZnS core/shell QDs are a safer alternative to CdSe/ZnS QDs for biological applications, by comparing their toxicity in vitro (cell culture) and in vivo (animal model Drosophila). By choosing QDs with comparable physical and chemical properties, we find that cellular uptake and localization is practically identical for these two nanomaterials.
Silica nanoparticles are widely used in various industrial fields and recently, they have been ex... more Silica nanoparticles are widely used in various industrial fields and recently, they have been exploited also for biomedical research. The impact of SiO2NPs on human health and the environment is thus of great interest. Nowadays, the overall evaluation of the toxicity/biocompatibility of SiO2NPs is extremely difficult, owing to controversial results in the literature and to the lack of standard procedures and/or insufficient characterization of the nanomaterials in biological systems.
Despite the extensive use of silica nanoparticles (SiO2NPs) in many fields, the results about the... more Despite the extensive use of silica nanoparticles (SiO2NPs) in many fields, the results about their potential toxicity are still controversial. In this work, we have performed a systematic in vitro study to assess the biological impact of SiO2NPs, by investigating 3 different sizes (25, 60 and 115 nm) and 2 surface charges (positive and negative) of the nanoparticles in 5 cell lines (3 in adherence and 2 in suspension).
The expected potential benefits promised by nanotechnology in various fields have led to a rapid ... more The expected potential benefits promised by nanotechnology in various fields have led to a rapid increase of the presence of engineered nanomaterials in a high number of commercial goods. This is generating increasing questions about possible risks for human health and environment, due to the lack of an in-depth assessment of the physical/chemical factors responsible for their toxic effects.
ACS nano
Bacterial adhesion onto inorganic/nanoengineered surfaces is a key issue in biotechnology and med... more Bacterial adhesion onto inorganic/nanoengineered surfaces is a key issue in biotechnology and medicine, because it is one of the first necessary steps to determine a general pathogenic event. Understanding the molecular mechanisms of bacteria-surface interaction represents a milestone for planning a new generation of devices with unanimously certified antibacterial characteristics. Here, we show how highly controlled nanostructured substrates impact the bacterial behavior in terms of morphological, genomic, and proteomic response. We observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) that type-1 fimbriae typically disappear in Escherichia coli adherent onto nanostructured substrates, as opposed to bacteria onto reference glass or flat gold surfaces. A genetic variation of the fimbrial operon regulation was consistently identified by real time qPCR in bacteria interacting with the nanorough substrates. To gain a deeper insight into the molecular basis of the interaction mechanisms, we explored the entire proteomic profile of E. coli by 2D-DIGE, finding significant changes in the bacteria adherent onto the nanorough substrates, such as regulations of proteins involved in stress processes and defense mechanisms. We thus demonstrated that a pure physical stimulus, that is, a nanoscale variation of surface topography, may play per se a significant role in determining the morphological, genetic, and proteomic profile of bacteria. These data suggest that in depth investigations of the molecular processes of microorganisms adhering to surfaces are of great importance for the design of innovative biomaterials with active biological functionalities.
Nano Research
The growing use of nanomaterials in commercial goods and novel technologies is generating increas... more The growing use of nanomaterials in commercial goods and novel technologies is generating increasing questions about possible risks for human health and environment, due to the lack of an in-depth assessment of their potential toxicity. In this context, we investigated the effects of citrate-capped gold nanoparticles (AuNPs) on the model system Drosophila melanogaster upon ingestion. We observed a significant in vivo toxicity of AuNPs, which elicited clear adverse effects in treated organisms, such as a strong reduction of their life span and fertility, presence of DNA fragmentation, as well as a significant overexpression of the stress proteins. Transmission electron microscopy demonstrated the localization of the nanoparticles in tissues of Drosophila. The experimental evidence of high in vivo toxicity of a nanoscale material, which is widely considered to be safe and biocompatible in its bulk form, opens up important questions in many fields, including nanomedicine, material science, health, drug delivery and risk assessment.
ACS nano, Jan 1, 2010
The development of appropriate in vitro protocols to assess the potential toxicity of the ever ex... more The development of appropriate in vitro protocols to assess the potential toxicity of the ever expanding range of nanoparticles represents a challenging issue, because of the rapid changes of their intrinsic physicochemical properties (size, shape, reactivity, surface area, etc.) upon dispersion in biological fluids. Dynamic formation of protein coating around nanoparticles is a key molecular event, which may strongly impact the biological response in nanotoxicological tests. In this work, by using citrate-capped gold nanoparticles (AuNPs) of different sizes as a model, we show, by several spectroscopic techniques (dynamic light scattering, UV-visible, plasmon resonance light scattering), that proteins-NP interactions are differently mediated by two widely used cellular media (i.e., Dulbecco Modified Eagle's medium (DMEM) and Roswell Park Memorial Institute medium (RPMI), supplemented with fetal bovine serum). We found that, while DMEM elicits the formation of a large time-dependent protein corona, RPMI shows different dynamics with reduced protein coating. Characterization of these nanobioentities was also performed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and mass spectroscopy, revealing that the average composition of protein corona does not reflect the relative abundance of serum proteins. To evaluate the biological impact of such hybrid bionanostructures, several comparative viability assays onto two cell lines (HeLa and U937) were carried out in the two media, in the presence of 15 nm AuNPs. We observed that proteins/NP complexes formed in RPMI are more abundantly internalized in cells as compared to DMEM, overall exerting higher cytotoxic effects. These results show that, beyond an in-depth NPs characterization before cellular experiments, a detailed understanding of the effects elicited by cell culture media on NPs is crucial for standardized nanotoxicology tests.
The interaction between cells and nanostructured materials is attracting increasing interest, bec... more The interaction between cells and nanostructured materials is attracting increasing interest, because of the possibility to open up novel concepts for the design of smart nanobiomaterials with active biological functionalities. In this frame we investigated the response of human neuroblastoma cell line (SH-SY5Y) to gold surfaces with different levels of nanoroughness. To achieve a precise control of the nanoroughness with nanometer resolution, we exploited a wet chemistry approach based on spontaneous galvanic displacement reaction. We demonstrated that neurons sense
and actively respond to the surface nanotopography, with a surprising sensitivity to variations of few nanometers. We showed that focal adhesion complexes, which allow cellular sensing, are strongly affected by nanostructured surfaces, leading to a marked decrease in cell adhesion. Moreover, cells adherent on nanorough surfaces exhibit loss of neuron polarity, Golgi apparatus fragmentation, nuclear condensation, and actin cytoskeleton that is not functionally organized. Apoptosis/necrosis assays established that nanoscale features induce cell death by necrosis, with a trend
directly related to roughness values. Finally, by seeding SH-SY5Ycells onto micropatterned flat and nanorough gold surfaces, we demonstrated the possibility to realize substrates with cytophilic or cytophobic behavior, simply by fine-tuning their surface topography at nanometer scale. Specific and functional adhesion of cells occurred only onto flat gold stripes, with a clear self-alignment of neurons, delivering a simple and elegant approach for the design and development of biomaterials with precise nanostructuretriggered biological responses.
Uploads
Papers by Virgilio Brunetti
and actively respond to the surface nanotopography, with a surprising sensitivity to variations of few nanometers. We showed that focal adhesion complexes, which allow cellular sensing, are strongly affected by nanostructured surfaces, leading to a marked decrease in cell adhesion. Moreover, cells adherent on nanorough surfaces exhibit loss of neuron polarity, Golgi apparatus fragmentation, nuclear condensation, and actin cytoskeleton that is not functionally organized. Apoptosis/necrosis assays established that nanoscale features induce cell death by necrosis, with a trend
directly related to roughness values. Finally, by seeding SH-SY5Ycells onto micropatterned flat and nanorough gold surfaces, we demonstrated the possibility to realize substrates with cytophilic or cytophobic behavior, simply by fine-tuning their surface topography at nanometer scale. Specific and functional adhesion of cells occurred only onto flat gold stripes, with a clear self-alignment of neurons, delivering a simple and elegant approach for the design and development of biomaterials with precise nanostructuretriggered biological responses.
and actively respond to the surface nanotopography, with a surprising sensitivity to variations of few nanometers. We showed that focal adhesion complexes, which allow cellular sensing, are strongly affected by nanostructured surfaces, leading to a marked decrease in cell adhesion. Moreover, cells adherent on nanorough surfaces exhibit loss of neuron polarity, Golgi apparatus fragmentation, nuclear condensation, and actin cytoskeleton that is not functionally organized. Apoptosis/necrosis assays established that nanoscale features induce cell death by necrosis, with a trend
directly related to roughness values. Finally, by seeding SH-SY5Ycells onto micropatterned flat and nanorough gold surfaces, we demonstrated the possibility to realize substrates with cytophilic or cytophobic behavior, simply by fine-tuning their surface topography at nanometer scale. Specific and functional adhesion of cells occurred only onto flat gold stripes, with a clear self-alignment of neurons, delivering a simple and elegant approach for the design and development of biomaterials with precise nanostructuretriggered biological responses.