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Team:Aachen/Project/2D Biosensor
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<!--Regarding the medium used for our sensor chips, LB medium showed a high background fluorescence when exposed to UV light in the Gel Doc. Surprisingly, the background fluorescence resulting from the LB medium was too high to detect a signal emitted by our sensor cells. Hence, minimal media (NA, M9, Hartman (HM)) was used to minimize background fluorescence, but this approach resulted in less to no growth of our sensor cells. In our device ''WatsOn'', optimized wavelengths of 450 nm and 480 nm were used for excitation of iLOV and GFP, respectively. When exposed to either excitation wavelength TB medium, which is basically an improved LB medium and highly supports cell growth, showed strong background fluorescence in our own device. High background fluorescence was also observed for TB medum when using the Gel Doc. In contrast to the Gel Doc LB medium showed minimal fluorescence in our device ''WatsOn'' and no difficulties in cultivation of our ''Cellocks'' were observed. Because of the reduced fluorescence compared to TB medium when using ''Watson'' for sensor chip evaluation and because of sufficient cultivation conditions for our 'Cellocks'' LB medium was chosen over TB mediium for sensor chip manufacturing. --> | <!--Regarding the medium used for our sensor chips, LB medium showed a high background fluorescence when exposed to UV light in the Gel Doc. Surprisingly, the background fluorescence resulting from the LB medium was too high to detect a signal emitted by our sensor cells. Hence, minimal media (NA, M9, Hartman (HM)) was used to minimize background fluorescence, but this approach resulted in less to no growth of our sensor cells. In our device ''WatsOn'', optimized wavelengths of 450 nm and 480 nm were used for excitation of iLOV and GFP, respectively. When exposed to either excitation wavelength TB medium, which is basically an improved LB medium and highly supports cell growth, showed strong background fluorescence in our own device. High background fluorescence was also observed for TB medum when using the Gel Doc. In contrast to the Gel Doc LB medium showed minimal fluorescence in our device ''WatsOn'' and no difficulties in cultivation of our ''Cellocks'' were observed. Because of the reduced fluorescence compared to TB medium when using ''Watson'' for sensor chip evaluation and because of sufficient cultivation conditions for our 'Cellocks'' LB medium was chosen over TB mediium for sensor chip manufacturing. --> | ||
| + | {{Team:Aachen/FigureFloat|Aachen_2_chipform.jpg|title=Sensor chip manufacturing using the closed mold|subtitle=When injecting the liquid agar into a closed mold we encounter problems due to frequent bubble formation.|left|width=500px}} | ||
=== Optimal agarose concentration for sensor chip manufacturing === | === Optimal agarose concentration for sensor chip manufacturing === | ||
For the sensor chip manufacturing, agarose was preferred over agar, because of a uniform linkage that resulted in a better chip homogeneity. In addition, agarose reduced diffusion of the inducer molecules through the chip. A reduced diffusion is vital to observe distinct fluorescent spots on the sensor chips and thus further optimzation of our 2D biosensor was done using agarose-based chips. | For the sensor chip manufacturing, agarose was preferred over agar, because of a uniform linkage that resulted in a better chip homogeneity. In addition, agarose reduced diffusion of the inducer molecules through the chip. A reduced diffusion is vital to observe distinct fluorescent spots on the sensor chips and thus further optimzation of our 2D biosensor was done using agarose-based chips. | ||
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=== Optimal chip configuration === | === Optimal chip configuration === | ||
Several approaches were tested for the production of agarose-based sensor chips with reproducible quality. The first approach was to cast every sensor chip individually. To achieve a plain chip surface (a requisite for high quality images), we casted the sensor chips between two microscope slides in an initial attempt. However, this approach was rejected, because the agar was too liquid and leaked from the microscope slides. In the second approach, we prepared a closed mold into which liquid agar was injected with a pipette, but we encountered a high number of bubbles in the resulting chips. Bubbles in the sensor chips interfered with fluorescence evaluation. Finally, we used an open mold into which the agar was poured right after mixing with the sensor cells. Chips were cut out along precast indentations in the casting mold after the agar solidified. An advantage of the open mold was the ability to simultaneously produce nine sensor chips while the surface tension of the liquid agar ensured a plane chip surface. | Several approaches were tested for the production of agarose-based sensor chips with reproducible quality. The first approach was to cast every sensor chip individually. To achieve a plain chip surface (a requisite for high quality images), we casted the sensor chips between two microscope slides in an initial attempt. However, this approach was rejected, because the agar was too liquid and leaked from the microscope slides. In the second approach, we prepared a closed mold into which liquid agar was injected with a pipette, but we encountered a high number of bubbles in the resulting chips. Bubbles in the sensor chips interfered with fluorescence evaluation. Finally, we used an open mold into which the agar was poured right after mixing with the sensor cells. Chips were cut out along precast indentations in the casting mold after the agar solidified. An advantage of the open mold was the ability to simultaneously produce nine sensor chips while the surface tension of the liquid agar ensured a plane chip surface. | ||
Revision as of 21:00, 17 October 2014
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