A UV-based photopolymerization process was studied and optimized to obtain Poly(ethylene glycol) methacrylate (PEG-MA) microchannels able to withstand high internal pressures (≈ 4 MPa). UV-based photopolymerization is one of the simplest, and most versatile lithographic technique, requiring short curing times (from seconds to minutes) and inexpensive manufacture equipment, ensuring good reproducibility. The influence of UV exposure time and PEG-MA conversion degree on microchannel geometries were studied by differential scanning calorimetry (DSC) to obtain microchannels with rectangular cross sections, controlled depth and sharp sidewalls. Such parameters were also the key to achieve an efficient sealing of the microchannels and to assure watertight adhesion between two PEG-MA cured surfaces. PEG-MA microchannels showed good properties such as biocompatibility, hydrophilicity, optical transparency, anti-fouling behavior and dimensional stability as consequence of PEG-MA mechanical (Young modulus 1.38 GPa) and thermal properties (Tg 110°C). Moreover, hydroxyl groups on the material surfaces can be exploited to move fluid along microchannels through electoosmotic flow (EOF). Microfluidic devices we obtained satisfy several requests for many biomedical applications such as polymerase chain reaction (PCR), cell sorting and cell counting and immunoassays.
In questo lavoro di tesi si affronta lo studio del processo di foto-polimerizzazione UV del polietilenglicole metacrilato (PEG-MA) per la fabbricazione di canali microfluidici in grado di resistere ad elevate pressioni (≈ 4 MPa). Tale processo è semplice, economico, versatile e permette una rapida prototipazione. I tempi di esposizione agli UV e il grado di reticolazione del PEG-MA sono stati studiati tramite analisi di calorimetria a scansione differenziale (DSC) per ottenere canali con sezioni trasversali rettangolari, profondità controllata e buona replicabilità. Tali parametri di processo, oltre ad influenzare la geometria delle microstrutture, sono fondamentali per studiare l’adesione fra diversi strati polimerizzati di PEG-MA ed ottenere un’efficiente sigillatura (sealing) dei microcanali. La biocompatibilità, l’idrofilicità e le proprietà anti-fouling del PEG-MA , insieme con le sue proprietà ottiche, meccaniche (modulo elastico 1.38 GPa) e termiche (Tg 110°C), hanno permesso di realizzare microcanali dimensionalmente stabili anche se sollecitati con alte pressioni interne e temperature elevate. Inoltre, i gruppi idrossilici (OH) delle catene di PEG permettono di sfruttare il fenomeno del flusso elettrosmotico (EOF) per movimentare elettricamente i fluidi all’interno dei microcanali. I dispositivi microfluidici ottenuti soddisfano le richieste di svariate applicazioni biomedicali quali la reazione a catena della polimerasi (PCR), conta e separazione cellulare e saggi immunologici.
Studio del processo di fabbricazione di canali microfluidici a base di polietilenglicole metacrilato
CREDI, CATERINA
2010/2011
Abstract
A UV-based photopolymerization process was studied and optimized to obtain Poly(ethylene glycol) methacrylate (PEG-MA) microchannels able to withstand high internal pressures (≈ 4 MPa). UV-based photopolymerization is one of the simplest, and most versatile lithographic technique, requiring short curing times (from seconds to minutes) and inexpensive manufacture equipment, ensuring good reproducibility. The influence of UV exposure time and PEG-MA conversion degree on microchannel geometries were studied by differential scanning calorimetry (DSC) to obtain microchannels with rectangular cross sections, controlled depth and sharp sidewalls. Such parameters were also the key to achieve an efficient sealing of the microchannels and to assure watertight adhesion between two PEG-MA cured surfaces. PEG-MA microchannels showed good properties such as biocompatibility, hydrophilicity, optical transparency, anti-fouling behavior and dimensional stability as consequence of PEG-MA mechanical (Young modulus 1.38 GPa) and thermal properties (Tg 110°C). Moreover, hydroxyl groups on the material surfaces can be exploited to move fluid along microchannels through electoosmotic flow (EOF). Microfluidic devices we obtained satisfy several requests for many biomedical applications such as polymerase chain reaction (PCR), cell sorting and cell counting and immunoassays.| File | Dimensione | Formato | |
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2011_12_Credi.pdf
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https://hdl.handle.net/10589/33803