@conference {1804, title = {Monitoring cell culture 3D microenvironments: oxygen and pH nano-sensors within hydrogels}, booktitle = {National Conference of Bioengineering}, year = {2012}, address = {Rome, Italy}, abstract = {

Ratiometric pH and O2 nanosensors were fabricated independently using a fluorophore that produces a signal proportional to the concentration of the analyte of interest, and a second fluorophore that produces a reference signal, insensitive to the analyte of interest. These fluorophores emit at different wavelengths and were either entrapped or covalently bound, within an inert optically transparent polymeric matrix. In this work uniform sized 3D micro-scaled alginate hydrogel constructs of approximately 100-300 $μ$m were fabricated. Through dual incorporation of HepG2 cells and nanosensors within these alginate constructs we aim to have a real-time, non-invasive method to measure microenvironmental pH and O2 content. Ratiometric fluorescent output from the microenvironment is used to monitor O2 concentrations and pH during cell culture. Measurements show that 3D micro-scaled constructs are suitable for cell growth and proliferation. Moreover O2 and pH values within the hydrogel cellularised microspheres are shown to have physiological values that enable the maintenance of the hepatic phenotype

}, keywords = {Bioengineering}, author = {Tirella, A and Carroll, L. A. and Aylott, J and A. Ahluwalia} } @conference {1800, title = {{Monitoring microconstructs: cell and nanosensor encapsulation in alginate micro-beads}}, booktitle = {TERMIS 3rd World Congress}, year = {2012}, address = {Vienna, Austria}, abstract = {

Monitoring and controlling the microenvironment of cell cultures is an ongoing challenge for many researchers. Much research has been conducted characterising individual aspects such as 3D architecture, mechanical properties, biochemicals, etc. The biggest deficits in existing models for monitoring analytes within the cellular environment is the lack of appropriate means for non invasive, real-time and integrated monitoring of the cellular responses. Nanosensors can overcome these issues: they are porous polymeric nanoparticles that are sensitive to a range of analytes including pH and O2. Microfabrication techniques are innovative tools to obtain controlled microstructures with a defined 3D architecture. In this work uniform sized 3D micro-scaled hydrogel constructs of approximately 300-400 um diameter were fabricated. Through dual incorporation of cells and nanosensors within these constructs we aim to have a real-time, non invasive method to measure microenvironmental pH value and O2 content. Ratiometric fluorescent output from the microenvironment is used to monitor O2 and pH during cell culture. Measurements show that 3D micro-scaled constructs are suitable for cell growth and proliferation. Moreover O2 content and pH within hydrogel cellularised microspheres are shown to have physiological values which enable the maintenance of the hepatic phenotype.

}, keywords = {Bioengineering, Nanotools}, author = {Tirella, A and A. Ahluwalia and Aylott, J and Carroll, L. A.} } @conference {1803, title = {A multi-stimuli environment for cardiac tissue engineering}, booktitle = {TERMIS 3rd World Congress}, year = {2012}, address = {Vienna, Austria}, abstract = {

The identification of the ideal cell source to generate cardiac tissue able to integrate into the host myocardium and with the contractile system is crucial for cardiac engineering. Amongst different cell sources so far proposed, human adult Cardiac Progenitor Cells (hCPCs) show the ability to proliferate and differentiate toward cardiac lineages when grown in appropriate microenvironmental conditions. It is widely accepted that conventional 2D cultures may provide a physiological environment for growing cells. For this reason the need to have an engineered microenvironment, matching physiological requirements, is crucial. A 3D context with spatial and time varying distribution of regulatory factors using mechanically matched scaffolds and bioreactors could represent an in vitro cell culture model being able to more closely reflects the in vivo conditions. In the present study, the possibility of using biocompatible and biodegradable scaffolds of collagen based or derivatives hydrogels in combination with Linneg/Sca-1pos hCPCs gathered from human heart biopsies was investigated. Bio-constructs were placed in the low shear, high flow MCmB (MultiCompartment modular Bioreactor) and the combined effects of dynamic culture conditions and 3D scaffolds on cell morphology and differentiation were studied in order to investigate the possibility of fabricating stem cell-derived cardiac patches to replace infarcted tissue.

}, keywords = {Bioengineering, Bioreactors, Dynamic 3D Cultures}, author = {Tirella, A and A. Ahluwalia and P. Di Nardo and Gaudiello, E and S. Giusti and F. Pagliari} } @conference {1805, title = {Modelling and realisation of smart graded hydrogel scaffolds}, booktitle = {Euromat-FEMS}, year = {2011}, address = {Montpellier, France}, abstract = {

European Congress and Exhibition on Advanced Materials and Processes - Poster F12-P-2-08

}, keywords = {Bioengineering}, author = {Tirella, A and G. Mattei and F. Montemurro and G. Vozzi and A. Ahluwalia} } @conference {1640, title = {Microfabbricazione di scaffold in alginato con propriet{\`a}~ meccaniche modulabili}, booktitle = {Congresso Nazionale Biomateriali 2008}, year = {2008}, pages = {{\textendash}}, keywords = {Bioengineering}, author = {Orsini, A and Tirella, A and A. Ahluwalia and G. Vozzi} } @conference {1634, title = {Microfabrication of Hydrogels scaffolds including cells and mechanical characterization}, booktitle = {Congresso Nazionale di Bioingegneria 2008}, year = {2008}, pages = {367-368}, address = {Pisa, Italy}, keywords = {Bioengineering}, author = {Tirella, A and G. Vozzi} } @conference {1794, title = {Microfluidic Gradient Maker for Pattern Generation}, booktitle = {TERMIS-EU}, year = {2008}, pages = {879}, address = {Porto, Portugal}, abstract = {

poster

}, keywords = {Bioengineering}, author = {Tirella, A and D. Mazzei and G. Vozzi and A. Ahluwalia} } @article {1489, title = {A microfluidic gradient maker for toxicity testing of bupivacaine and lidocaine}, journal = {Toxicology in vitro}, volume = {22}, year = {2008}, pages = {1957{\textendash}64}, abstract = {

A great deal of effort is being dedicated to the development of new devices able to conduct effective in vitro toxicology analyses. This paper describes the use of a microfluidic gradient maker for the toxicological analysis of two conventional local anesthetics, bupivacaine and lidocaine on cell cultures. The microfluidic device was designed and simulated using COMSOL Multiphysics and the concentration gradient in the microfluidic network was analysed through a fluidodynamic and diffusive study. Subsequently the device was fabricated with soft lithography, casting PDMS in a master to obtain channels about 250 microm deep. Both drugs were tested on C2C12 myoblasts and an analysis was performed using propidium iodide staining followed by an imaging processing routine to obtain quantitative dose-response profiles in the gradient maker. The system was critically compared with microwell-based toxicity testing. The results show that the GM is a more sensitive method for detection of cell toxicity, and compared with testing of drug toxicity using microwells with individual cell cultures, allows one shot testing with a single cell culture exposed to a large number of concentrations. However, the flow rates required to obtain a suitable concentration range across the device may damage shear sensitive cells.

}, keywords = {Bioengineering}, issn = {0887-2333}, doi = {10.1016/j.tiv.2008.09.016}, url = {http://www.ncbi.nlm.nih.gov/pubmed/18940244}, author = {Tirella, A and Marano, M and Vozzi, F. and A. Ahluwalia} }