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Dr Styliani Totti

My publications


The presence of ultrasound-induced cavitation in sonodynamic therapy (SDT) treatments has previously enhanced the activity and delivery of certain sonosensitisers in biological systems. The purpose of this work was to investigate the potential for two novel anti-cancer agents from natural derivatives, sanguinarine and ginger root extract (GRE), as sonosensitisers in an SDT treatment with in vitro PANC-1 cells. Both anti-cancer compounds had a dose-dependent cytotoxicity in the presence of PANC-1 cells. A range of six discreet ultrasound power-frequency configurations were tested and it was found that the cell death caused directly by ultrasound was likely due to the sonomechanical effects of cavitation. Combined treatment used dosages of 100 ¼M sanguinarine or 1mM of GRE with 15 s sonication at 500 kHz and 10 W. The sanguinarine-SDT and GRE-SDT treatments showed a 6% and 17% synergistic increase in observed cell death, respectively. Therefore both sangunarine and GRE were found to be effective sonosensitisers and warrant further development for SDT, with a view to maximising the magnitude of synergistic increase in toxicity.
Totti S, Vernardis S, Meira L, Pérez-Mancera P, Costello E, Greenhalf W, Palmer D, Neoptolemos J, Mantalaris A, Velliou E (2017) Designing a bio-inspired bio-mimetic in vitro system for the optimisation of ex vivo studies of pancreatic cancer, Drug Discovery Today 22 (4) pp. 690-701 Elsevier
Pancreatic cancer is one of the most aggressive and lethal human malignancies. Drug therapies and radiotherapy are used for treatment as adjuvants to surgery, but outcomes remain disappointing. Advances in tissue engineering point that three-dimensional cultures can reflect the in vivo tumour micro-environment and can guarantee a physiological distribution of oxygen, nutrients and drugs, therefore, being promising low cost tools for therapy development. In this work we review crucial elements, i.e., structural and environmental, that should be considered for an accurate design of an ex vivo platform for studies of pancreatic cancer. Furthermore, we propose environmental stress response biomarkers as platform readouts for the efficient control and further prediction of the pancreatic cancer response to the environmental and treatment input.
Garriga R, Jurewicz I, Seyedin S, Bardi N, Totti S, Matta? Domjan B, Velliou E, Alkhorayef M, Cebolla V, Razal J, Dalton A, Muñoz E (2017) Multifunctional, Biocompatible and pH-Responsive Carbon Nanotube- and Graphene Oxide/Tectomer Hybrid Composites and Coatings, Nanoscale 9 pp. 7791-7804 Royal Society of Chemistry
Here we present a route for non?covalent functionalization of carboxylated multi?wall carbon nanotubes and graphene oxide with novel two?dimensional peptide assemblies. We show that self?assembled amino?terminated biantennary and tetraantennary oligoglycine peptides (referred to as tectomers) effectively coat carboxylated multi?walled carbon nanotubes and also strongly interact with graphene oxide due to electrostatic interactions and hydrogen bonding as the driving force, respectively. The resulting hybrids can be made into free?standing conducting composites or applied in the form of thin, pH?switchable bioadhesive coatings onto graphene oxide fibers. Monitoring of cell viability of pancreatic cell lines, seeded on those CNT hybrids, show that they can be used as two? and three?dimensional scaffolds to tissue engineer tumour models for studying ex vivo the tumour development and response to treatment. This highly versatile method in producing pH?responsive hybrids and coatings offers an attractive platform for a variety of biomedical applications and for the development of functional materials such as smart textiles, sensors and bioelectronic devices.
Pancreatic ductal adenocarcinoma is an aggressive disease with an extremely low survival rate. This is due to the (i) poor prognosis and (ii) high resistance of the disease to current treatment options. The latter is partly due to the very complex and dense tissue/tumour microenvironment of pancreatic cancer, which contributes to the disease?s progression and the inhibition of apoptotic pathways. Over the last years, advances in tissue engineering and the development of three-dimensional (3D) culture systems have shed more light into cancer research by enabling a more realistic recapitulation of the niches and structure of the tumour microenvironment. Herein, for the first time, 3D porous polyurethane scaffolds were fabricated and coated with fibronectin to mimic features of the structure and extracellular matrix present in the pancreatic cancer tumour microenvironment. The developed 3D scaffold could support the proliferation of the pancreatic tumour cells, which was enhanced with the presence of fibronectin, for a month, which is a significantly prolonged in vitro culturing duration. Furthermore, in situ imaging of cellular and biomarker distribution showed the formation of dense cellular masses, the production of collagen-I by the cells and the formation of environmental stress gradients (e.g. HIF-1±) with similar heterogeneity trends to the ones reported in in vivo studies. The results obtained in this study suggest that this bioinspired porous polyurethane based scaffold has great potential for in vitro high throughput studies of pancreatic cancer including drug and treatment screening.
Microneedle devices offer minimally invasive and rapid biomarker extraction from the skin. However, the lack of effective assessment tools for such microneedle devices can delay their development into useful clinical applications. Traditionally, the microneedle performance is evaluated i) in vivo, using animal models, ii) ex vivo, on excised human or animal skin or iii) in vitro, using homogenised solutions with the target antigen to model the interstitial fluid. In vivo and ex vivo models are considered the gold-standard approach for the evaluation of microneedle devices because of their structural composition, however they do exhibit limitations. More specifically, they have limited availability and they present batch-to-batch variations depending on the skin origin. Furthermore, their use rises ethical concerns regarding compliance with the globally accepted 3Rs principle of reducing the use of animals for research purposes. At the same time, in vitro models fail to accurately mimic the structure and the mechanical integrity of the skin tissue that surrounds the interstitial fluid. In this study, we introduce for the first time an animal-free, mechanically robust, 3D scaffold that has great potential as an accurate in vitro evaluation tool for immunodiagnostic microneedle devices. More specifically, we demonstrate, for the first time, successful extraction and detection of a melanoma biomarker (S100B) using immunodiagnostic microneedles in the 3D culture system. Melanoma cells (A375) were cultured and expanded for 35 days in the highly porous polymeric scaffold followed by in situ capture of S100B with the microneedle device. Scanning electron microscopy showed a close resemblance between the 3D scaffold and human skin in terms of internal structure and porosity. The microneedle device detected S100B in the scaffold (with a detection pattern similar to the positive controls), while the biomarker was not detected in the surrounding liquid supernatants. Our findings demonstrate the great potential of this animal-free 3D tool for rapid and low-cost evaluation of microneedle devices.