Surface plasmon resonance (SPR) based sensors have become the “gold standard” for label-free biosensing. While conventional SPR sensing is widely used as a result of its high detection resolution, the prism-based setup and oblique angle of incidence make it difficult to miniaturize and align. Additionally, SPR spectroscopy faces the challenge for multiplexing due to the poor time and spatial resolution of the spectrometers employed to detect the reflected light at different wavelengths. Though SPR imaging/microscopy (SPRi/SPRM) has attracted great attention in recent years to overcome the multiplexing issue, the prism-based setup still makes it difficult to miniaturize or scale up. Moreover, for imaging purpose, the oblique reflection angle and tilted image plane lead to optical aberration and difficulty in focusing. In addition, the prism-based setup prevents the usage of optics with high numerical apertures, limiting the spatial resolution and the corresponding sensing spot size.
This dissertation focuses on a novel nanoplasmonic interferometer imaging system for biomolecular sensing. The straightforward collinear geometry and the nanostructured plasmonic sensor array makes it simpler to scale up and multiplex. The nanoplasmonic biosensor yields a high mass resolution off 4.1 × 10−5 refractive index unit (RIU) with a footprint down to 9.8 × 9.8 μm2, surpassing other label-free technologies for biosensing. The biosensor was employed to detect matrix metalloproteinase 9 (MMP-9) secretion at different timepoints from human monocytic cells, THP-1 after lipopolysaccharide (LPS) stimulation. The results are in good match with enzyme-linked immunosorbent assay (ELISA), but is more efficient and in a label-free fashion. The nanoplasmonic imaging sensing platform offers an opportunity for multiplexed sensing of different secretory molecules, holding a great potential for the study of the dynamics and interplay of cell secretion signals.
|Commitee:||Cheng, Xuanhong, Kumar, Sushil, Vavylonis, Dimitrios|
|School Location:||United States -- Pennsylvania|
|Source:||DAI-B 81/12(E), Dissertation Abstracts International|
|Subjects:||Electrical engineering, Engineering|
|Keywords:||Biosensing, Interferometry, Plasmonics|
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