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▼ [6p-PB5-10] Nanoplasmonic enhanced micro- structured chip for single cell sensing application
Keywords:Localized surface plasmonic resonance, microwell, thermal imprint
Protein secretion monitoring provides intercellular cell activity information that can be used as early indication of infectious diseases in the human body. It is common to use average response from bulk cell as primary cell activity observation. However, this standard method do obscures any individual cell momentous response over large population of cell, hiding any important signal to highlight. Therefore it is necessary to isolate cell into single cell position, reducing cell to cell contact arrangement before observe its intercellular activities. To address this issue, we developed label free new sensing platform that combine micro – structure microwell array that able to isolate individual cell with nanoplasmonic sensing capacity that can be used to observe real time intercellular activity.
Clean Aluminum oxide electrode undergoes two-step anodizing procedure. Specific design was develop using Su8 photoresist forming 60µm diameter disk on this surface. Prepared mould was used to emboss 188µm thickness Zf-14 cyclo olefin polymers (COP) with high pressure. Finally, gold layer was sputtered forming micro and nano structure on its surface. Imaging observation reveals mushroom look-alike nano-structures with average diameters of 190nm and micro-structured microwells with diameters of 70 µm in single chip.
The sensitivity prepared plasmonic device was further evaluated over various surrounding refractive index environments, including air (n=1.0), water (n=1.33), 1M glucose (n=1.35), ethylene glycol (n=1.43) and glycerol (n=1.47). Under these surrounding, our plasmonic device shows red-shifted behavior with sensitivity calculated at 274nm/RIU. Next, trapping capacity of prepared microwell design was calculated by allowing 20um beads solution (~1200 beads) to sediment for 30minutes before number beads isolated in each microwell was determined. It is found that, 14% of total microwell was showing single cell isolation phenomena.
Several fixed protein Anti IgA concentration in serum free media H4182 (Sigma) was applied to understand plasmonic behavior on our chip. Absorbance spectrum revealed limit of detection (LOD) as low as 10ng/ul Anti IgA solution as shown in figure 1. The study results indicate our unique plasmonic platform suitable for single cell isolation with simultaneous intercellular protein secretion observation. New effort is taken to increase LOD and observe real time cell protein secretion measurement in future.
Clean Aluminum oxide electrode undergoes two-step anodizing procedure. Specific design was develop using Su8 photoresist forming 60µm diameter disk on this surface. Prepared mould was used to emboss 188µm thickness Zf-14 cyclo olefin polymers (COP) with high pressure. Finally, gold layer was sputtered forming micro and nano structure on its surface. Imaging observation reveals mushroom look-alike nano-structures with average diameters of 190nm and micro-structured microwells with diameters of 70 µm in single chip.
The sensitivity prepared plasmonic device was further evaluated over various surrounding refractive index environments, including air (n=1.0), water (n=1.33), 1M glucose (n=1.35), ethylene glycol (n=1.43) and glycerol (n=1.47). Under these surrounding, our plasmonic device shows red-shifted behavior with sensitivity calculated at 274nm/RIU. Next, trapping capacity of prepared microwell design was calculated by allowing 20um beads solution (~1200 beads) to sediment for 30minutes before number beads isolated in each microwell was determined. It is found that, 14% of total microwell was showing single cell isolation phenomena.
Several fixed protein Anti IgA concentration in serum free media H4182 (Sigma) was applied to understand plasmonic behavior on our chip. Absorbance spectrum revealed limit of detection (LOD) as low as 10ng/ul Anti IgA solution as shown in figure 1. The study results indicate our unique plasmonic platform suitable for single cell isolation with simultaneous intercellular protein secretion observation. New effort is taken to increase LOD and observe real time cell protein secretion measurement in future.