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In recent years, it has been verified that collective cell migration is a fundamental step in tumor spreading and metastatic processes. In this paper, we demonstrate for the first time how low-intensity ultrasound produces long-term inhibition of collective migration of epithelial cancer cells in wound healing processes. In particular, we show how pancreatic tumor cells, PANC-1, grown as monolayers in vitro respond to these waves at frequencies close to 1 MHz and low intensities (<100mWcm−2) for 48–72 h of culture after some minutes of a single ultrasound irradiation. This new strategy opens a new line of action to block the spread of malignant cells in cancer processes. Despite relevant spatial variations of the acoustic pressure amplitude induced in the assay, the cells behave as a whole, showing a collective dynamic response to acoustic performance. Experiments carried out with samples without previous starving showed remarkable effects of the LICUs from the first hours of culture, more prominent than those with experiments with monolayers subjected to fasting prior to the experiments. This new strategy to control cell migration demonstrating the effectiveness of LICUS on not starved cells opens a new line of action to study effects of in vivo ultrasonic actuation on tumor tissues with malignant cells. This is a proof-of-concept study to demonstrate the physical effects of ultrasound stimulation on tumor cell migration. An in-depth biological study of the effects of ultrasounds and underlying biological mechanisms is on-going but out of the scope of this article.

Hybrid materials have been studied because in these materials the properties of organic components, such as elasticity and biodegradability, could be combined with the properties of inorganic components, such as good biological response, thereby transforming them into a single material with improved properties. In this work, Class I hybrid materials based on polyester-ureaurethanes and titania were obtained using the modified sol–gel method. This was corroborated using the FT-IR and Raman techniques which highlighted the formation of hydrogen bonds and the presence of Ti–OH groups in the hybrid materials. In addition, the mechanical and thermal properties and degradability were measured using techniques, such as Vickers hardness, TGA, DSC, and hydrolytic degradation; these properties could be tailored according to hybridization between both organic and inorganic components. The results show that Vickers hardness increased by 20% in hybrid materials as compared to polymers; also, the surface hydrophilicity increases in the hybrid materials, improving their cell viability. Furthermore, cytotoxicity in vitro test was carried out using osteoblast cells for intended biomedical applications and they showed non-cytotoxic behavior

Pancreatic cancer is considered to be one of the most lethal types of cancer, presenting a 90% of mortality of its total incidence each year. Study of the biological and physical cues driving collective cell migration and subsequent cancer metastasis is still a major challenge that need to be understood. The main objective of this project would be to create three-dimensional hydrogel constructs based on sodium alginate (S.A.), allowing the study of pancreatic tumoral cells (PANC-1) migration. Three alginate-based bioinks with different viscoelastic properties have been prepared and PANC-1 collective cell migration was analyzed. Alginate inks have been characterized and printability was optimized by FT-IR and rheology analysis. For the migration studies, the bioinks were placed in transwells cell wells with no proliferation medium. Migrated cells were counted after 48 hours from the bottom of the wells using a Coulter analyzer. Fluorescent PAULA Cell Imager was used to analyze the live/death ratio of the cells. Printability tests suggest the possibility for these inks to be further translated to 3D bioprinting techniques. Fluorescence analysis has shown the influence of the crosslinker in the survival rate of the cells. Then, migration percentage of PANC-1 cells in alginate bioinks appears to be favoured in hydrogels presenting higher values for their loss tangent.

Organic-inorganic hybrid materials overcome drawbacks associated with alginate hydrogels. In this work, covalently coupled silica-alginate hybrids were prepared by Schiff base formation and sol-gel reaction using alginate dialdehyde (ADA), (3- Aminopropyl) triethoxysilane (APTES), and APTES/tetraethylorthosilicate (TEOS) precursors. The influence of the polysaccharide/inorganic ratio, the nature of the inorganic precursor and the ionic crosslinking ability are studied. Prepared hybrids were characterized by FT-IR, 13C and 29Si -NMR spectroscopies, SEM, and rheology. For ADA/APTES hybrids, at higher ADA content, Schiff base formation is predominant, but at lower ADA content, the sol-gel reaction is prevalent. However, the progress of the sol-gel reactions for ADA/(APTES+TEOS), is favored with higher ADA compositions. Introducing a posterior ionic crosslinking treatment was possible, increasing the moduli in ADA/(APTES+TEOS) hybrids from 86207Pa for 1.5 ADA/Si to 362171Pa for 1.5 ADA/Si-Ca. In-situ ADA-Silica hybrid hydrogels containing both ionic and covalent crosslinking can be successfully synthesized with the proposed method.