@article {3349, title = {Systemic and vascular inflammation in an in-vitro model of central obesity}, journal = {PLoS ONE}, year = {2018}, month = {02/2018}, abstract = {

Metabolic disorders due to over-nutrition are a major global health problem, often associated with obesity and related morbidities. Obesity is peculiar to humans, as it is associated with lifestyle and diet, and so difficult to reproduce in animal models. Here we describe a model of human central adiposity based on a 3-tissue system consisting of a series of interconnected fluidic modules. Given the causal link between obesity and systemic inflammation, we focused primarily on pro-inflammatory markers, examining the similarities and differences between the 3-tissue model and evidence from human studies in the literature. When challenged with high levels of adiposity, the in-vitro system manifests cardiovascular stress through expression of E-selectin and von Willebrand factor as well as systemic inflammation (expressing IL-6 and MCP-1) as observed in humans. Interestingly, most of the responses are dependent on the synergic interaction between adiposity and the presence of multiple tissue types. The set-up has the potential to reduce animal experiments in obesity research and may help unravel specific cellular mechanisms which underlie tissue response to nutritional overload.

}, keywords = {Bioengineering}, doi = {https://doi.org/10.1371/journal.pone.0192824.s001}, url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0192824}, author = {A. Ahluwalia and A. Misto and G. Vozzi and C. Magliaro and G. Mattei and Marescotti MC and AVOGARO, A and Iori, E.} } @article {2833, title = {Sample, testing and analysis variables affecting liver mechanical properties: A review}, journal = {Acta Biomaterialia}, year = {2016}, abstract = {

Given the critical role of liver mechanics in regulating cell response and directing the development of tissue fibrosis, accurately characterising its mechanical behaviour is of relevance for both diagnostic purposes as well as for tissue engineering and for the development of in-vitro models. Determining and quantifying the mechanical behaviour of soft biological tissues is, however, highly challenging due to their intrinsic labile nature. Indeed, a unique set of values of liver mechanical properties is still lacking to date; testing conditions can significantly affect sample status and hence the measured behaviour and reported results are strongly dependent on the adopted testing method and configuration as well as sample type and status. This review aims at summarising the bulk mechanical properties of liver described in the literature, discussing the possible sources of variation and their implications on the reported results. We distinguish between the intrinsic mechanical behaviour of hepatic tissue, which depends on sample variables, and the measured mechanical properties which also depend on the testing and analysis methods. Finally, the review provides guidelines on tissue preparation and testing conditions for generating reproducible data which can be meaningfully compared across laboratories.

}, keywords = {Bioengineering}, doi = { http://dx.doi.org/10.1016/j.actbio.2016.08.055}, url = {http://www.sciencedirect.com/science/article/pii/S1742706116304603}, author = {A. Ahluwalia and G. Mattei} } @conference {2275, title = {Sensorized Squeeze Pressure Bioreactor For mechanical modulation of cardiomyocyte phenotype}, booktitle = {Journal of tissue engineering and regenerative medicine}, volume = {8 Suppl 1}, year = {2014}, pages = {67{\textendash}8}, keywords = {Bioengineering}, doi = {10.1002/term.1943}, url = {http://www.ncbi.nlm.nih.gov/pubmed/24912686}, author = {S. Giusti and Vozzi, F. and F. Pagliari and Tirella, A and D. Mazzei and Cabiati, M and S. del Ry and A. Ahluwalia} } @article {2204, title = {Smart Sensing Scaffolds}, journal = {Smart Membranes and Sensors: Synthesis, Characterization, and Applications}, year = {2014}, pages = {337}, keywords = {Bioengineering}, author = {C. De Maria and Whulanza, Y. and G. Vozzi and A. Ahluwalia} } @article {2290, title = {Sphyga: a multiparameter open source tool for fabricating smart and tunable hydrogel microbeads}, journal = {Biofabrication}, volume = {6}, year = {2014}, keywords = {Bioengineering}, doi = {10.1088/1758-5082/6/2/025009}, author = {Tirella, A and C. Magliaro and M. Penta and M. Troncone and Pimentel, R and A. Ahluwalia} } @conference {1793, title = {{SpHyGa: fabrication of hepatic lobule replicas using tissue derived material composites}}, booktitle = {ESB 2013}, year = {2013}, pages = {ID 520}, address = {Madrid}, keywords = {Bioengineering}, author = {M. La Marca and Tirella, A and G. Mattei and A. Ahluwalia} } @article {2281, title = {SQPR 3.0: A Sensorized Bioreactor for Modulating Cardiac Phenotype}, journal = {Procedia Engineering}, volume = {59}, year = {2013}, pages = {219{\textendash}225}, abstract = {

In cardiac tissue engineering, the use of bioreactors is fundamental for applying controlled mechanical stimuli on cells and recreate a physiological environment for cardiomyocyte cultures. This work is focused on the design of a sensorized Squeeze Pressure bioreactor (SQPR 3.0) able to apply a periodic contactless hydrodynamic pressure on tissue constructs. This system was then tested with H2c9, a murine cardiomyoblast cell line, to investigate the effect of different stimulation times (2h, 24h, 30h) on cell shape and cardiotypic marker expression.

}, keywords = {Bioengineering}, issn = {18777058}, doi = {10.1016/j.proeng.2013.05.114}, url = {http://linkinghub.elsevier.com/retrieve/pii/S187770581301028X}, author = {S. Giusti and F. Pagliari and Vozzi, F. and Tirella, A and D. Mazzei and Cabiati, M and S. del Ry and A. Ahluwalia} } @article {1790, title = {{Strain rate viscoelastic analysis of soft and highly hydrated biomaterials.}}, journal = {Journal of biomedical materials research. Part A}, year = {2013}, abstract = {

Measuring the viscoelastic behaviour of highly hydrated biological materials is challenging because of their intrinsic softness and labile nature. In these materials it is difficult to avoid pre-stress and therefore to establish precise initial stress and strain conditions for lumped parameter estimation using creep or stress-relaxation tests. We describe a method ($ε$M or epsilon dot method) for deriving the viscoelastic parameters of soft hydrated biomaterials which avoids pre-stress and can be used to rapidly test degradable samples. Standard mechanical tests are first performed compressing samples using different strain rates. The dataset obtained is then analysed to mathematically derive the material{\textquoteright}s viscoelastic parameters. In this work a stable elastomer, PDMS, and a labile hydrogel, gelatin, were first tested using the $ε$M, in parallel stress-relaxation was used to compare lumped parameter estimation. After demonstrating that the elastic parameters are equivalent and that the estimation of short time constants is more precise using the proposed method, the viscoelastic behaviour of porcine liver was investigated using this approach. The results show that the constitutive parameters of hepatic tissue can be quickly quantified without the application of any pre-stress and before the onset of time dependent degradation phenomena.

}, keywords = {Bioengineering}, issn = {1552-4965}, doi = {10.1002/jbm.a.34914}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23946054}, author = {Tirella, A and G. Mattei and A. Ahluwalia} } @article {1512, title = {Sensing scaffolds to monitor cellular activity using impedance measurements}, journal = {BIOSENSORS \& BIOELECTRONICS}, year = {2011}, keywords = {Bioengineering}, issn = {0956-5663}, author = {Whulanza, Y and Ucciferri, N and C. Domenici and G. Vozzi and A. Ahluwalia} } @article {2284, title = {Squeeze pressure bioreactor: a hydrodynamic bioreactor for noncontact stimulation of cartilage constructs}, journal = {Tissue engineering. Part C, Methods}, volume = {17}, year = {2011}, pages = {757{\textendash}64}, abstract = {

A novel squeeze pressure bioreactor for noncontact hydrodynamic stimulation of cartilage is described. The bioreactor is based on a small piston that moves up and down, perpendicular to a tissue construct, in a fluid-filled chamber. Fluid displaced by the piston generates a pressure wave and shear stress as it moves across the sample, simulating the dynamic environment of a mobile joint. The fluid dynamics inside the squeeze pressure bioreactor was modeled using analytical and computational methods to simulate the mechanical stimuli imposed on a construct. In particular, the pressure, velocity field, and wall shear stress generated on the surface of the construct were analyzed using the theory of hydrodynamic lubrication, which describes the flow of an incompressible fluid between two surfaces in relative motion. Both the models and in-situ pressure measurements in the bioreactor demonstrate that controlled cyclic stresses of up to 10 kPa can be applied to tissue constructs. Initial tests on three-dimensional scaffolds seeded with chondrocytes show that glycosaminoglycan production is increased with regard to controls after 24 and 48 h of cyclic noncontact stimulation in the bioreactor.

}, keywords = {Bioengineering}, issn = {1937-3392}, doi = {10.1089/ten.TEC.2011.0002}, url = {http://online.liebertpub.com/doi/abs/10.1089/ten.tec.2011.0002 http://www.ncbi.nlm.nih.gov/pubmed/21410315}, author = {C. De Maria and S. Giusti and D. Mazzei and A. Crawford and A. Ahluwalia} } @inbook {2285, title = {The Squeeze Pressure Bioreactor: Design and Modelling of a Non-Contact Device for Mechanical Stimulation of Tissue Engineered Constructs}, booktitle = {Bioreactors: Design, Properties and Applications}, year = {2011}, pages = {199{\textendash}214}, publisher = {Nova Science Publishers, Inc.}, organization = {Nova Science Publishers, Inc.}, address = {Hauppauge NY}, abstract = {

Diseases of hyaline cartilage represent one of the major health problems, especially in industrialized countries with high life expectancy. The erosion of the articulating surfaces of joints, known as osteoarthritis, currently affects more than 200 million citizens worldwide, and more than 50\% of the patients need or will need a surgical treatment. Articular cartilage is a three dimensional avascular tissue, which covers the ends of all synovial joints. During normal daily function, articular cartilage can be repeatedly subjected to forces up to several time body weight, but it is able to provide articulating joints with a nearly frictionless motion. Despite its tremendously important function, articular cartilage has limited capacity for auto regeneration after degenerative and rheumatic diseases, like arthritis, as well as traumatic injuries. Cartilage problems are a huge and still unsolved medical issue, which therefore represents one of the most important tissue engineering targets requiring high quality products as fast as possible. For this reason, the possibility to recreate in vitro cartilage substitutes as a real alternative to total joint replacement represents an increasing and hopeful market, in which many research groups are still working. At the moment, one of the main findings in invitro cartilage studies is the importance of the role of mechanical stimuli and dynamic loads for the chondrocytes growth and differentiation. Several studies using cartilage explants or chondrocytes seeded in 3D scaffolds have shown that mechanical compressive loads affect the cells metabolic activity and their matrix production. In order to simulate the in vivo environment, the use of bioreactors is becoming fundamental: bioreactors can provide the chemical and mechanical signals that optimize tissue development. Furthermore, bioreactors could be an important instrument to reduce the cost of clinical studies, used as in vitro predictors of in vivo performance. In this way,the use of bioreactors can reduce animal studies, helping the scientists to focus their attention in the right direction before starting pre-clinical studies, which are usually more expensive than preliminary research. In the past few years, several systems for the application of different mechanical stimuli to chondrocytes have been developed. Most of these can generate biomechanical-like forces such as the direct compression, tensile and shear forces, or hydrostatic pressure, in order to stimulate the articular chondrocyctes to increase their matrix production. Generally, the most important requirements that a culture system has to satisfy are high reliability and usability, perfect sterility, easy control of all the important culture parameters and low cost. In this work, a new system, inspired by the synovial environment of mobile joints and able to apply an innovative type of stimulation on articular chondrocytes is described and modeled. The SQPR (SQueeze PRessure) bioreactor chamber is designed to impose a cyclic hydrodynamic pressure on cell cultures, constructs or tissues slices. The basic principle of this new system is the generation of a localized contact less overpressure on articular chondrocytes, using a simple vertical piston movement. This kind of stimulation is particularly useful for neo-tissue or fresh-constructs, in which cells require a dynamic environment to maintain their differentiate state, but at the same time do not tolerate direct compression or high shear stress. When the piston moves down, a controlled hydrodynamic overpressure and a shear stress is generated over the cell surface, stimulating the chondrocytes to improve their matrix production. The fluid dynamics inside the SQPR bioreactor is illustrated from an analytical and numerical point of view. We show how these models can predict the pressure, velocity field and wall shear stress generated on the cell surface of the construct. The bioreactor design is presented in detail and validation tests on chondrocytes are described.

}, keywords = {Bioengineering}, url = {https://www.novapublishers.com/catalog/product\_info.php?products\_id=22653}, author = {S. Giusti and A. Ahluwalia and C. De Maria}, editor = {Antolli, P. G. and Z. Liu} } @article {1488, title = {Substrate stiffness influences high resolution printing of living cells with an ink-jet system}, journal = {Journal of bioscience and bioengineering}, volume = {112}, year = {2011}, pages = {79{\textendash}85}, abstract = {

The adaptation of inkjet printing technology for the realisation of controlled micro- and nano-scaled biological structures is of great potential in tissue and biomaterial engineering. In this paper we present the Olivetti BioJet system and its applications in tissue engineering and cell printing. BioJet, which employs a thermal inkjet cartridge, was used to print biomolecules and living cells. It is well known that high stresses and forces are developed during the inkjet printing process. When printing living particles (i.e., cell suspensions) the mechanical loading profile can dramatically damage the processed cells. Therefore computational models were developed to predict the velocity profile and the mechanical load acting on a droplet during the printing process. The model was used to investigate the role of the stiffness of the deposition substrate during droplet impact and compared with experimental investigations on cell viability after printing on different materials. The computational model and the experimental results confirm that impact forces are highly dependent on the deposition substrate and that soft and viscous surfaces can reduce the forces acting on the droplet, preventing cell damage. These results have high relevance for cell bioprinting; substrates should be designed to have a good compromise between substrate stiffness to conserve spatial patterning without droplet coalescence but soft enough to absorb the kinetic energy of droplets in order to maintain cell viability.

}, keywords = {Bioengineering}, issn = {1347-4421}, doi = {10.1016/j.jbiosc.2011.03.019}, url = {http://www.ncbi.nlm.nih.gov/pubmed/21497548}, author = {Tirella, A and Vozzi, F. and C. De Maria and G. Vozzi and Sandri, T and Sassano, D and Cognolato, L and A. Ahluwalia} } @article {1278, title = {Supporto per camere di coltura cellulare}, year = {2011}, month = {11/2011}, keywords = {Bioengineering}, issn = {MI2011A002073}, author = {A. Ahluwalia and Sbrana, T. and D. Mazzei} } @conference {1530, title = {Sensorised "Smart" Scaffold to Monitor Cell Processes Based on Impedance Characteristics}, booktitle = {Congresso Nazionale di Bioingegneria 2010}, year = {2010}, keywords = {Bioengineering}, author = {Whulanza, Y and Ucciferri, N and G. Vozzi and A. Ahluwalia and C. Domenici} } @conference {1526, title = {Site Specific Nano-Tuning of Scaffolds Using Inkjet Printing}, booktitle = {NIP Conference}, year = {2010}, address = {Austin, Texas }, keywords = {Bioengineering}, author = {Tirella, A and F. Montemurro and Vinci, B. and Vozzi, F. and G. Vozzi and Sassano, D and Sandri, T and Cognolato, L and A. Ahluwalia} } @conference {1639, title = {Sviluppo e caratterizzazione meccanica di scaffold a base di collagene per la rigenerazione della cartilagine}, booktitle = {Congresso Nazionale Biomateriali 2008}, year = {2008}, pages = {{\textendash}}, keywords = {Bioengineering}, author = {G. Mattei and F. Montemurro and A. Ahluwalia and G. Vozzi} }