Multiplexed photonic membranes and related detection methods for chemical and/or biological sensing applications

Abstract

Photonic detection systems and methods are shown. A flow through photonic membrane is provided with pores which are distributed along multiple regions. The pores of one region have walls to which a first type of target specific anchor can be attached, while pores of another region have walls to which a second type of target specific anchor can be attached. An additional region of pores without anchors can be provided, so that optical detection occurs differentially. A stack of photonic membranes is also provided. The diameter of the pores of one photonic membrane is larger than the diameter of the pores of another photonic membrane, thus allowing also determination of the size of a target organism flown through the stack of membranes.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application claims the priority benefit of U.S. Provisional Application 60 / 993,740 filed on Sep. 13, 2007, which is incorporated herein by reference in its entirety.FIELD[0002]The present disclosure relates to photonic membranes. More in particular, it relates to flow through photonic membranes for chemical and / or biological sensing applications and related detection methods.BACKGROUND[0003]Recently, interest has emerged in label-free optical affinity-based biosensors, which allow to study bio-organisms without fluorescence or radiolabels, and thus dramatically simplify assays. Typically, affinity-based biosensors detect the presence of a target molecule by selective binding to a capture probe. For optical biosensors, binding translates into a change of optical properties, i.e. the complex refractive index or luminescence.[0004]Optical detection methods based on complex refractive index transduction include interferometry in m...

AI Technical Summary

Benefits of technology

[0024]According to an embodiment of the present application, Applicants show a 2D photonic crystal, in particular a 2D flow through photonic membrane, in which the refractive index periodicity is constituted of alternating layers of bulk silicon and air (well defined channels). This design leads to a dramatic reduction of the detection limit since the device is sensitive to local changes of refractive index in each channel (by opposition to the effective refractive index change that has to occur across the entire porous silicon structure shown on FIG. 3), ultimately leading to single organism detection capabilities for these platforms.

[0025]The teachings of the present disclosure provide a viable solution to technology gaps in the Biological Warfare (BW) and Chemical Warfare (CW) detection areas. A real-time capability has been identified to detect, identify, characterize, locate, and warn against BW (and CW) agent threats. The proposed devices and methods combine collection, concentration, and detection of differently sized bio-organisms or chemical agents onto a single platform: an integrated system of photonic waveguiding silicon membranes.

[0026]The approach of the present disclosure eliminates the current spatial and temporal disconnection between on-field sample collection and laboratory analysis. Because of the strong light-confinement properties of photonic crystal microcavities (high quality factor, or high-Q), it is expected that detection is allowed down to a single organism and will only require a very small sensing area (˜10-100 μm2) and very small amounts of sample (˜1-10 fL). In addition, since the membrane allows flow-through, Applicants also expect that much larger volumes of analyte can be accommodated when available, and even further promoted by a three-dimensional staggered filtration architecture. A further advantage of the flow-through geometry according to the present disclosure is that it improves the binding probability of the target organism to the molecular probes anchored on the pore walls.

Problems solved by technology

Indeed, the detection limit for a porous silicon crystal is inherently high because transduction is generated by a change of effective refractive index that has to occur across the entire volume of the crystal.

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