Multiplexed specific label-free detection of NCI-H358 lung cancer cell line lysates with silicon based photonic crystal microcavity biosensors
2013
Chakravarty, Swapnajit | Lai, Wei-Cheng | Zou, Yi | Drabkin, Harry A. | Gemmill, Robert M. | Simon, George R. | Chin, Steve H. | Chen, Ray T.
We experimentally demonstrate label-free photonic crystal (PC) microcavity biosensors in silicon-on-insulator (SOI) to detect the epithelial–mesenchymal transition (EMT) transcription factor, ZEB1, in minute volumes of sample. Multiplexed specific detection of ZEB1 in lysates from NCI-H358 lung cancer cells down to an estimated concentration of 2 cells per micro-liter is demonstrated. L13 photonic crystal microcavities, coupled to W1 photonic crystal waveguides, are employed in which resonances show high Q in the bio-ambient phosphate buffered saline (PBS). When the sensor surface is derivatized with a specific antibody, the binding of the corresponding antigen from a complex whole-cell lysate generates a change in refractive index in the vicinity of the photonic crystal microcavity, leading to a change in the resonance wavelength of the resonance modes of the photonic crystal microcavity. The shift in the resonance wavelength reveals the presence of the antigen. The sensor cavity has a surface area of ∼11μm2. Multiplexed sensors permit simultaneous detection of many binding interactions with specific immobilized antibodies from the same bio-sample at the same instant of time. Specificity was demonstrated using a sandwich assay which further amplifies the detection sensitivity at low concentrations. The device represents a proof-of-concept demonstration of label-free, high throughput, multiplexed detection of cancer cells with specificity and sensitivity on a silicon chip platform.
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