Pennacchio, Fabrizio Andrea (2017) Fabrication And Development of innovative 3D platforms for cell biology by 2-photon lithography. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Lingua: English
Title: Fabrication And Development of innovative 3D platforms for cell biology by 2-photon lithography
Pennacchio, Fabrizio
Date: 10 April 2017
Number of Pages: 111
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Chimica, dei Materiali e della Produzione Industriale
Dottorato: Ingegneria dei prodotti e dei processi industriali
Ciclo di dottorato: 29
Coordinatore del Corso di dottorato:
Netti, Paolo AntonioUNSPECIFIED
Date: 10 April 2017
Number of Pages: 111
Uncontrolled Keywords: Gelatin; microfabrication; hydrogel; cell instructive materials; 3D lithography;
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-IND/34 - Bioingegneria industriale
Date Deposited: 25 Apr 2017 17:40
Last Modified: 08 Mar 2018 14:18
DOI: 10.6093/UNINA/FEDOA/11780


The hard processing conditions of natural and nature-derived hydrogels, whose potential in cellular applications is well established, strongly limit their employment in the realization of advanced systems for guiding cells behavior. In the first part of the thesis an overview on the main 3D micro-fabrication techniques to produce instructive platforms for cell engineering application is provided with special emphasis on the principles and main uses of the direct laser writing two-photon polymerization (DLW 2PP) process. The application of this technique to the fabrication of synthetic, natural and natural derived hydrogel 3D structures is presented, highlighting its current potentialities and limits. Special attention is devoted to the versatility of a biomaterial like gelatin and its broad spectrum of applications, as this is the core subject of the thesis which aims to further expand gelatin use by proposing new approaches to develop innovative platforms for specific cell engineering applications. In Chapter 2 we defined the composition of a gelatin-based photoresist to fabricate complex and high resolute microstructures with our 3D lithography system (Nanoscribe Professional GT). We first synthetized and characterized an acrylate gelatin which was mixed with an azobenzene based crosslinker and with a photoinitiator compatible with our system specifications. Then, the fabrication process was optimized in terms of process parameters and writing strategy. Moreover we proved the fundamental role of the azobenzene in the fabrication of stable structures. Finally, we characterized the polymerized gelatin showing physical properties compatible with many cellular applications. In Chapter 3 we developed a gelatin-based platform for the mechanical stimulation of cells; to this end we studied a strategy in which cells were first positioned and then exposed to mechanical stresses. To control cell positioning we used the Nanoscribe to introduce a novel topographic signal that strongly affected the cell adhesion process. Cells were mechanically stimulated by the light induced microstructures deformation due to the azobenzene crosslinker isomerization. As light source we employed the laser of a confocal microscope to promote a significant material photo-deformation. To get an in-depth comprehension of the photo-deformation mechanical properties of the material were analysed after light exposure. Adopting this strategy we were then able to selectively deform living cells down to the single cell level. In Chapter 4 we exploited same gelatin as instructive building blocks designed to guide, with specific topographic patterns, the production of anisotropic oriented micro-tissue for tissue engineering applications. To this endwe used the Nanoscribe as a rapid prototyping technique to test the efficiency of the aforementioned topographic signal. Once demonstrated the importance of the topography in determining the micro-tissue orientation, we tried to build up a droplet microfluidic device for the massive production of tubular gelatin patterned emulsions. More specifically, to pattern the gelatin surface, we performed an in-chip 3D lithography process to insert specific 3D extrusion micro-heads strategically positioned into the device. The large scale production of the gelatin blocks by exploiting such microfluidic device is under development.


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