Investigator at CRANN Deputy Coordinator of FP7 project at Institute of Molecular Medicine and CRANN Part-time lecturer in BioMEMS and Nanomedicine at Trinity College Dublin
Senior scientist involved in developing and advancing several multidisciplinary research projects between University, Research Hospital and Industry partners for future applications in medicine and nanotechnology industry.
Dr Prina-Mello has been also actively working with technology transfer SMEs and large Industrial Firms to deliver the next biomedical device generation
Main research areas: Nanomaterials for Regenerative Medicine and Drug Delivery, Biosensors for Diagnostics and Nanomedicine, Nanotoxicology and Environmental toxicology, and Nanotechnology applications for medical industry and clinical research.
Abstract: Platelet aggregation is essential for vascular haemostasis and thrombosis. To improve the therapy of arterial thrombotic disorders and identify novel therapeutic targets it is imperative to study basic mechanisms of platelet thrombus formation. To date most data on biology, physiology and pharmacology of platelet aggregation have been obtained by studying this phenomenon under static or quasi-dynamic conditions at the macroscale level. There is a widespread recognition for the need of new technologies that will help to further elucidate the role of platelets in physiological and pathological thrombus formation and to design more effective and specific antithrombotic drugs. Micro- and nanofluidic devices, capable of reaching nanoscale resolution, can be used for this purpose setting the scene for the development of novel methods for studying platelet function in physiology, pathology and therapeutics.
Abstract: The dispersion of highly hydrophobic carbon materials such as carbon nanotubes in biological media is a challenging issue. Indeed, the nonspecific adsorption of proteins occurs readily when the nanotubes are introduced in biological media; therefore, a methodology to control adsorption is in high demand. To address this issue, we developed a bifunctional linker derived from pyrene that selectively enables or prevents the adsorption of proteins on single-wall carbon nanotubes (SWNTs). We demonstrated that it is possible to decrease or completely suppress the adsorption of proteins on the nanotube sidewall by using proper functionalization (either covalent or noncovalent). By subsequently activating the functional groups on the nanotube derivatives, protein adsorption can be recovered and, therefore, controlled. Our approach is simple, straightforward, and potentially suitable for other biomolecules that contain thio or amino groups available for coupling.
Abstract: Abstract The use of fibre-shaped nanomaterials in commercial applications has met with concern that they could cause health effects similar to those seen with pathogenic fibres such as certain forms of asbestos. Of the attributes which form the fibre pathogenicity paradigm, fibre length is thought to be a critical factor in determining fibre toxicity. We have previously shown that carbon nanotubes display such length-dependent pathogenicity but it remains unclear if other forms of fibrous nanomaterials conform to the fibre pathogenicity paradigm. As such, our aim is to determine the generality of this hypothesis by asking whether a radically different form of fibrous nanomaterial, nickel nanowires, show length-dependent pathogenicity. Our results indicate that nickel nanowires synthesised to be predominantly long (>20 μm) show the ability to elicit strong inflammation in the mouse peritoneal model in a dose-dependent manner; inflammation or fibrosis was not seen with the short (<5 μm) nanowires. This length-dependent response was also seen after lung aspiration and within a macrophage in vitro model adding further weight to the contention that fibre length is an important driver of hazard potential. This may have important implications when considering the hazard posed by fibrous nanomaterials and their regulation in workplaces.
Abstract: Single-walled carbon nanotubes (SWNTs) are promising candidates for a wide range of biomedical applications due to their fascinating properties. However, safety concerns are raised on their potential human toxicity and on the techniques that need to be used to assess such toxicity. Here, we integrate for the first time 3D tissue-mimetic models in the cytotoxicity assessment of purified (p-) and oxidized (o-) SWNTs. An established ultrasound standing wave trap was used to generate the 3D cell aggregates, and results were compared with traditional 2D cell culture models. Protein-based (bovine serum albumin) and surfactant-based (Pluronic F68) nanotube dispersions were tested and compared to a reference suspension in dimethyl sulfoxide. Our results indicated that p- and o-SWNTs were not toxic in the 3D cellular model following a 24 h exposure. In contrast, 2D cell cultures were significantly affected by exposure to p- and o-SWNTs after 24 h, as assessed by high-content screening and analysis (HCSA). Finally, cytokine (IL-6 and TNF-α) secretion levels were elevated in the 2D but remained essentially unchanged in the 3D cell models. Our results strongly indicate that 3D cell aggregates can be used as alternative in vitro models providing guidance on nanomaterial toxicity in a tissue-mimetic manner, thus offering future cost-effective solutions for toxicity screening assays under the experimental conditions more closely related to the physiological scenario in 3D tissue microenvironments.
Abstract: Active T cell locomotion depends on efficient repeated cycles of integrin receptor/ligand interactions mediating cell adhesion and detachment, intracellular signaling cascades orchestrating posttranslation modifications of interacting proteins, dynamic reassembly of participating cytoskeletal elements, and structural support of associated scaffolding molecules. Using an integrated approach based on novel cutting edge technologies of live cell imaging, cell transfection, proteomics, and nanotechnology, we provide here a detailed characterisation of crucial mechanisms involved in LFA-1 integrin-mediated T cell migration. Polarization and phenotypic changes associated with LFA-1-triggered T cell locomotion is largely dependent on the intact functioning of the microtubule cytoskeleton. Experiments utilizing 4-D (3-D over time) confocal live imaging of T cells, microinjected with fully functional constructs encoding protein kinase C beta (PKC-beta) isoenzyme tagged with enhanced green fluorescent protein (GFP), elucidate that LFA-1-induced activation is associated with translocation of PKC-beta to sites associated with centrosomes and tubulin cytoskeleton in locomotory T lymphocytes. We also provide here a characterization of a novel microfluidics-based multichannel platform enabling detailed analysis of leukocyte adhesion and migration under regulated shear stress conditions. Using precision machined surfaces, we demonstrate that the substrate topography can influence the motile response of the two different T cell types in different ways, and this can be quantified in terms of specified motility parameters. Finally, using an original in situ immunoprecipitation method, in which LFA-1 antibodies are utilized to induce intracellular association of proteins in the cytoskeletal/signaling complex, we demonstrate that this complex includes a number of structural and signaling proteins, which have been identified by 2-D electrophoresis and MALDI-TOF protein sequencing.
Abstract: Endothelial cells at the interface between the bloodstream and the vessel wall are continuously subjected to mechanical stimulation in vivo, and it widely recognised that such stimulation plays an important role in cardiovascular physiology. Cell deformation is induced by mechanical forces such as cyclic stretch, fluid shear stress, and transmural pressure. Although much of the work in this field has dealt with the effect of fluid shear stress, very little is known about how cyclic forces modulate and alter the morphology of single endothelial cells, and thereafter, how they effect the confluent layer of endothelial cells lining the vessel wall. The aim of this study is to investigate the response of endothelial cells when subjected to substrate deformation of similar magnitude to those experienced in vivo. Human umbilical vein endothelial cells (HUVEC) were cultured on plasma-treated silicone strips and uni-axially cyclically stretched using a custom made mechanical device. Results showed that endothelial cells subject to 10% deformation for as little as 4 h reoriented perpendicular to the stretch direction. In addition, although no integrin coating was applied to the substrate, it was found that plasma-treated silicone provided a cell adhesion substrate comparable to the commonly used collagen type I. Thus the results show that the stretch stimulus alone affects the morphology of endothelial cells. Further studies are required to establish the relative importance of substrate strain vs. fluid flow stimuli.
Abstract: Articular cartilage has a limited capacity for self-regeneration and none of the current treatments or therapies that are used to rectify damaged cartilage are ideal or permanent. As a result, researchers are looking to tissue engineering to grow constructs in vitro with the view of implanting them into joints to replace damaged tissue. This approach would omit disadvantages associated with current treatments such as taking allografts from less weight bearing regions to be inserted into the defect or penetrating the subchondral bone to allow stem cells to migrate into the damaged area. Approaches used in cartilage tissue engineering involve the application of mechanical stimuli to cells to emulate the forces experienced by cells in vivo. This review analyses the present situation in current state-of-the-art bioreactors and looks at the various cell types and substrates used in such studies.
