Critical angle reflection imaging for quantification of molecular interactions
AssigneeArizona Board of Regents on behalf of Arizona State University
InventorsShaopeng Wang, Runli Liang, Guangzhong Ma
Life of this patent
Estimating the term…
Abstract
This disclosure describes systems and methods for critical angle reflection (CAR) imaging to quantify molecular binding kinetics on a glass surface in some embodiments. CAR is a label-free method that measures the reflectivity change near a critical angle in response to molecular binding induced refractive index changes on the sensor surface. The sensitivity and dynamic range of CAR is tunable by varying the incident angle of light, which allows for optimizing the measurement for ligands with different sizes in both biomolecular and cell-based studies.
Claims15
A method of detecting molecular interactions, the method comprising:
- contacting a liquid comprising a ligand with a first surface of a substrate functionalized with a receptor displayed on a surface of a cell that is disposed on the first surface of the substrate, wherein the substrate is optically transparent bare glass free of a coating and wherein a refractive index of the substrate exceeds a refractive index of the liquid;
- introducing an incident light into an optical prism toward a second surface of the substrate at an incident angle with respect to a plane perpendicular to the first surface of the substrate, wherein the second surface is opposite the first surface and the incident angle is less than a critical angle defined as sin−1(na/ng), wherein ng is the refractive index of the substrate and na is the refractive index of the liquid;
- obtaining one or more differential critical angle reflection (CAR) images of the cell from light reflected at an interface of the liquid and the first surface of the substrate;
- and
- identifying one or more moving parabolic patterns within the cell in the differential CAR images and/or a cell membrane deformation of the cell and a surface refractive index change in the differential CAR images, thereby detecting the molecular interactions.
An optical imaging system comprising:
- an optically transparent substrate having a first surface and a second surface opposite the first surface, wherein the optically transparent substrate is bare glass free of a coating and wherein the first surface of the optically transparent substrate is functionalized with a receptor displayed on a surface of a cell that is disposed on the first surface of the optically transparent substrate;
- an optical prism configured to be coupled to the second surface of the optically transparent substrate;
- a light source configured to introduce collimated light into the optical prism at an incident angle with respect to a plane perpendicular to the second surface of the optically transparent substrate, wherein the incident angle is less than a critical angle defined as sin−1(na/ng), wherein ng is a refractive index of the substrate and na is a refractive index of the liquid, and wherein the light source is further configured to vary the incident angle to tune a sensitivity and dynamic ranges to selected levels;
- a detector configured to obtain one or more differential critical angle reflection (CAR) images of the cell from light reflected from an interface of the first surface of the optically transparent substrate and a liquid in contact with the first surface of the optically transparent substrate;
- and
- a processor configured to identify one or more moving parabolic patterns within the cell in the differential CAR images and/or a cell membrane deformation of the cell and a surface refractive index change in the differential CAR images when a liquid comprising a ligand is contacted with the first surface of the optically transparent substrate.
Dependencies are inferred from the claim text.