A combined electrospinning and microestrusion apparatus

Combined electrospinning and microextrusion apparatus, comprising a robotic manipulator (10) provided with a plurality of degrees of freedom, an end effector (20) supported and movable by the robotic manipulator (10), a plurality of extruders (30) housed on the end effector (20), each of the extruders being provided with an interchangeable nozzle (3 1) for the extrusion of at least one material, a working plane (40) configured for the deposition of the extruded material, a pneumatic circuit (120) configured to supply a fluid flow to the extruders (30) for controlling the extrusion of the material, and an electric generator (50) selectively activatable to apply a potential difference between the nozzles (3 1) of the extruders (30) and the working plane (40), whereby the extruders (30) are capable of operating selectively in microextrusion mode with inactive electric generator or in electrospinning mode with active electric generator, in an independent manner from each other

Design and fabrication of a novel 3D in vitro model of the blood-retinal barrier

In order to investigate the pathophysiological process underlying age-related macular degeneration (AMD) and to validate novel drug candidates, several in vivo and in vitro models have been proposed. However, none of these has proven to be reliable to mimic the complex cellular interactions in the outer blood-retinal barrier (oBRB) with physiological realism and great predictive value. This thesis presents the design and fabrication of a novel oBRB-on-a-chip model as a biomimetic platform for AMD understanding and for new therapeutic agents development. The device is a 3D microfluidic platform consisting of a biomimetic blood vessel network mimicking the choroidal vascular network (CVN) and of a novel engineered membrane mimicking the Bruch’s membrane (BrM) both housed within a single-chamber which resembles the intraocular space and enables the co-culture of human retinal pigment epithelium (RPE) and endothelial cells above the BrM and inside the CVN respectively. The microfluidic network, designed starting from medical images, was fabricated from polydimethylsiloxane (PDMS) through a novel manufacturing method established to provide a time-saving and cost-effective alternative to the common lithographic-based techniques. The interior surfaces of the microfluidic channels were subsequently coated with chemically crosslinked gelatin to promote cell adhesion and long-term culture. The engineered BrM was fabricated from chemically crosslinked gelatin by electrospinning process to get porous, ultrathin and nanofibrous membranes mimicking the mechanical, chemical and physical properties of the native substrate. The co-culture chamber with a common internal footprint with the wells in standard 24-well plates was fabricated from PDMS via the moulding process. Finite Element Analysis (FEA) was used for the understanding of the physical phenomena which occur inside the designed and fabricated bioreactor and for the validation of design approaches. Perfusion tests were successfully performed using the microfluidic platform. Human embryonic stem cell-derived RPE (hESC-RPE) cells and HUVECs cells were cultured on the engineered BrM and on PDMS-gelatin substrates respectively to evaluate cells adhesion and proliferation under static conditions. Immunofluorescence techniques and optical microscope observation demonstrated that engineered BrMs supported functional RPE monolayer formation, while HUVECs cells shown good adhesion and proliferation on the PDMS-gelatin substrates. Tests of dynamic seeding and static/dynamic co-culture tests were performed with the HUVECs cells

Apparato combinato di elettrofilatura e microestrusione

Apparato combinato di elettrofilatura e mi-croestrusione, comprendente un manipolatore robotico (10) dotato di una pluralità di gradi di libertà, un effettore finale (20) supportato e movimen-tabile dal manipolatore robotico (10), una pluralità di estrusori (30) alloggiati sull’effettore finale (20), ciascuno degli estruso-ri essendo provvisto di un ugello intercambiabile (31) per l’estrusione di almeno un materiale, un piano di lavoro (40) configurato per la de-posizione del materiale estruso, un circuito pneumatico (120) configurato per alimentare un flusso di fluido agli estrusori (30) per controllare l’estrusione del materiale, e un generatore elettrico (50) selettivamente attivabile per applicare una differenza di poten-ziale fra gli ugelli (31) degli estrusori (30) e il piano di lavoro (40), per cui gli estrusori (30) sono in grado di operare selettivamente in modalità di microestrusione con generatore elettrico inatti-vo o in modalità di elettrofilatura con generatore elettrico attivo, in maniera indipendente l’uno dall’altro. (Figura 2

A COMBINED ELECTROSPINNING AND MICROEXTRUSION APPARATUS

Combined electrospinning and microextrusion apparatus, comprising a robotic manipulator (10) provided with a plurality of degrees of freedom, an end effector (20) supported and movable by the robotic manipulator (10), a plurality of extruders (30) housed on the end effector (20), each of the extruders being provided with an interchangeable nozzle (31) for the extrusion of at least one material, a working plane (40) configured for the deposition of the extruded material, a pneumatic circuit (120) configured to supply a fluid flow to the extruders (30) for controlling the extrusion of the material, and an electric generator (50) selectively activatable to apply a potential difference between the nozzles (31) of the extruders (30) and the working plane (40), whereby the extruders (30) are capable of operating selectively in microextrusion mode with inactive electric generator or in electrospinning mode with active electric generator, in an independent manner from each other