Optical Biosensing of Multiple Disease Markers in a Photonic-Band-Gap Lab-on-a-Chip: A Conceptual Paradigm

A conceptual paradigm for multiparametric optical biosensing in a lab-on-a-chip, using the cascaded transmission of light through a photonic crystal that contains microfluidic channels and is embedded in a glass slide, is demonstrated. Accurate detection of multiple disease-identifying biomarkers is facilitated by the interaction of surface and photonic-band-gap waveguide modes. Through finite-difference time-domain simulations, levels of light transmission through the device are shown to be simultaneously responsive to analyte bindings and layer thicknesses at different locations along a single optical transmission path through the photonic crystal. Our multiparametric biosensing mechanism supersedes traditional single-resonance-shift-based biosensing and provides a more detailed spectral fingerprint of various diseases or various stages of a given disease. Moreover, the spectral line shape due to the engineered optical modes can logically discriminate between different concentrations of several analytes flowing through the microfluidic channels. The simultaneous detection and differentiation of (combinations of) distinct analytes using a single measurement on one device offers a paradigm for optical biosensing.