Porous membrane waveguide sensors and sensing systems therefrom for detecting biological or chemical targets
Inventors
Rong, Guoguang • Mernaugh, Raymond L. • Weiss, Sharon M.
Assignees
National Science Foundation NSF
Publication Number
US-8506887-B2
Publication Date
2013-08-13
Expiration Date
2029-10-16
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Abstract
A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size<2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.
Core Innovation
Embodiments of the invention describe porous membrane waveguide sensors and sensing systems for detecting biological or chemical targets. The sensor includes a membrane comprising a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material comprises a plurality of voids having an average size less than 2 microns. At least one receptor having structure for binding to the target is immobilized within the plurality of voids. An optical coupler couples light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.
The background problem addressed by the invention relates to the limitations of conventional biosensors, especially label-free sensors such as surface plasmon resonance (SPR), fiber optic, and planar waveguide sensors, which rely on evanescent fields interacting with biomolecules immobilized on sensor surfaces. These sensors have limited sensitivity for small molecule detection due to small surface areas and weak interactions between biomolecules and the electromagnetic field. The present invention aims to improve sensitivity for detecting small molecules by employing porous membranes with large surface areas and receptors immobilized within voids inside the membrane, thereby enhancing interaction with the waveguide mode.
In various embodiments, the porous membrane waveguide sensor includes a membrane with voids small enough (less than about 2 microns, often less than 1 micron or 0.5 microns) to support guided and leaky optical waveguide modes. The voids provide a large internal surface area where receptors bind target molecules, causing refractive index changes within the membrane detectable via shifts in waveguide resonance angles, wavelengths, or intensity. The invention encompasses sensor chips with optically transparent support layers and cladding layers to enable integration with optical systems and potential use as disposable sensor components. The sensing system further includes optical blocks, light sources, and detectors configured to detect changes induced by target binding.
Claims Coverage
The patent includes two independent claims covering a sensor and a sensing system incorporating a porous membrane waveguide for detecting biological or chemical targets.
A sensor with a single porous membrane layer supporting waveguide modes
The sensor comprises essentially a single layer of porous material with voids averaging less than 2 microns that supports generation and propagation of at least one waveguide mode. At least one receptor capable of binding the target is immobilized within the voids. An optical coupler, which may be a prism or a grating, couples light to the membrane sufficient to generate the waveguide mode. A cladding layer (ambient gas, liquid buffer, or polyvinyl formal) separates the membrane and the optical coupler.
A sensing system with a sensor having a substrate support layer and optical components
The sensing system includes a sensor with a substrate support layer that has at least one opening exposing a membrane consisting essentially of a single layer of porous material supporting at least one waveguide mode, with voids averaging less than 2 microns and receptors bound within the voids. An optical block coupler (prism or grating) couples light to the membrane sufficient to generate the waveguide mode, with a cladding layer (ambient gas, liquid buffer, or polyvinyl formal) between the membrane and optical block. A light source provides photons and a light detector detects photons reflected by the optical block.
The independent claims cover a sensor and a sensing system featuring a porous, single-layer membrane that supports waveguide modes with receptors immobilized within its voids, employing optical couplers such as prisms or gratings and a cladding layer, enabling sensitive detection of biological or chemical targets via optical waveguide phenomena.
Stated Advantages
Enhanced sensitivity for detecting small molecules compared to conventional SPR and fiber optic sensors due to large surface area from porous membrane and strong field confinement within the membrane.
Minimized absorption losses by coupling light through low-loss optical paths such as prisms and cladding layers, avoiding high-loss thick substrates.
Capability to detect a wide variety of biological and chemical materials and simultaneous detection of multiple targets by using regions of the porous membrane with different receptors.
Compatibility and integration with existing commercial sensor instrumentation, enabling use as disposable sensor chips and potential integration with on-chip light sources and photodetectors for compact designs.
Documented Applications
Medical diagnostics for biomolecule sensing.
Food safety monitoring.
Anti-bioterrorism detection of biological or chemical targets.
Environmental monitoring for biological and chemical substances.
Homeland security applications.
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