Abstract 5317: Photonic crystal microarray sensing of breast cancer cell line lysates

Abstract

Abstract Monitoring of protein expression changes in cells or in real tissue is commonly based on western blot and protein microarray. However, these assays have limitations that include lack of detection sensitivity and accuracy. Furthermore, fluorescent, radioactive or magnetic tags or labels are typically needed for signal transduction, which may not always be preferable, as more and more new markers are being discovered. In this study, we have used our silicon chip based label free high throughput high sensitivity XtremeSens Diagnostics benchtop nanophotonic platform to detect the target proteins that are regulated by TAM67. The platform has currently demonstrated the smallest sensor on chip with the highest sensitivity down to 67femtograms per milliliter with specificity. The target proteins were selected based on western blot results which shows that when Tam67 is overexpressed in MCF-7 Tam67 clone cells, PCNA is up-regulated; ß-catenin, cyclinD1, p-EGFR expression are down-regulated, and E-cadherin seems to have no change. The probe antibodies were printed on unique photonic crystal microcavities and cell lysates were detected by a label-free method. The assay is based on the highly sensitive photonic crystal platform in silicon-on-insulator chips in which light-matter interaction is enhanced due to confinement and guiding of light on length scales of the wavelength of light. The probe proteins are immobilized on unique photonic crystal microcavities in the array. All sensors are exposed to the analyte at the same instant of time. The binding interaction alters the refractive index of the resonance cavity and this is detected as a shift in the resonance wavelength trapped by the device. The resonance shift is detected directly and does not require any secondary labeling. Specificity is demonstrated using a sandwich assay in which a second antibody was introduced following the initial binding and washing steps and a secondary resonance wavelength shift is observed. The impact of this study will provide the wide range of applications including the study of cancer biomarker, signal transfection pathway, clinical diagnosis of diseases, commercialization potential is envisioned in other civilian markets such as environmental pollution sensing, food pathogen detection and biodefense. Citation Format: Swapnajit Chakravarty, Naimei Tang, Hai Yan, Chun-ju Yang, Yi Zou, Qiang Shen, Ray Chen. Photonic crystal microarray sensing of breast cancer cell line lysates. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5317. doi:10.1158/1538-7445.AM2014-5317