C - DTU Nanotech - Danmarks Tekniske Universitet

6.1 Materials and Methods 43
• Drilling machine 16 BS Klee
• CO2–laser Duo Lase R○ Synrad
• CO2–laser software WinMarkPro 4.1.1 Synrad
• PMMA plates 100x100x1.5 mm 3 Nordisk Plast Danmark
• PMMA foil 0.25 mm Röhm
• Sticky tape Heat resistant Scotch
• Heater ITO PE film 0.20 mm Sigma Aldrich
• Temperature sensor 256–045 Rs–components
• Spin coater Spin 150 APT
• PVC–tube o/i–ø 2.3/0.8 mm Vwr
• Heat wire WSD-1 Monacor
• Profilometer Dektak 8 Veeco
Method
For designing the bio–microreactor, the interconnections, the reactor chamber with the heat
device and the sampling chamber with the Peltier element had to be built.
Interconnections
Since the bio–microreactor was developed as a plug in system, interconnections between the
different parts were very important.
Silastic M O–rings
O–ring interconnections consisted of a Silastic M O–ring and a small metal capillary. To
integrate an O–ring into a channel, a cavity was made into a channel and the O–ring was
thermally bonded between two PMMA plates (Fig. 6.2). A capillary could be plugged into
the channel through the O–rings and leaking could be prevented this way.
For producing the O–ring with an inner diameter of 0.24 mm, a maximum outer diameter of
2.0 mm and a height of 2.0 mm, a mold was made with the CO2–laser in PMMA. The mold
consisted of two equivalent parts which were bonded together thermally. The dimensions of
one part were 20x40x1.5 mm 3 . The standard shape for thermal bonding was used (section
5.1.1). For producing the mold a circular structure (consisting of eight circles) with injection