Convex Lens-Induced Confinement for Measuring Distributions of Molecular Size

Abstract

A curved surface is placed tangent to a slide and displaces a sample liquid from the point or line of contact outward. Imaging indicates a region where fluorescence is observed, and the location of the fluorescence indicates the molecular size. The radius of curvature of the lens is known, the distance from the (center) point of contact of the observed fluorescence is measured with a microscope and the distance of the lens surface to the slide's surface can then be calculated. This distance represents the size of the molecule or ensemble of molecules emitting. Similarly, absorbance, etc. could be measured with a light source below the slide.

What is claimed is: 
     
         1 - 32 . (canceled) 
     
     
         33 . A method for analyzing a molecule, comprising:
 applying a liquid sample containing molecules to be analyzed to a sample measurement surface;   contacting the sample measurement surface with a curved surface positioned tangent to the sample measurement surface at a point or line of contact to confine the sample to sub focal depth thicknesses;   subjecting the sample to imaging by optical microscopy; and   performing optical analysis to obtain information characteristic of the molecules.   
     
     
         34 . The method of  claim 33 , wherein the curved surface comprises a convex or cylindrical lens. 
     
     
         35 . The method of  claim 33 , wherein the curved surface is obtained by deflecting a flexible sheet disposed above the sample measurement surface into contact with the sample measurement surface. 
     
     
         36 . The method of  claim 33 , further comprising:
 analyzing the spatial profile of the intensity as a function of the distance between the curved and planar surfaces in order to measure the diameter or distribution of diameters of the contained molecules   
     
     
         37 . The method of  claim 33 , further comprising:
 analyzing the spatial profile of the intensity as a function of the distance between the curved and planar surfaces in order to measure the shape or aspect ratio of the contained molecules   
     
     
         38 . The method of  claim 33 , wherein the confinement distance ranges from about 2 nm to 1000 nm. 
     
     
         39 . The method of  claim 33 , wherein the sample measurement surface comprises a flow cell having an upper and a lower surface for containing the sample to measured, the curved surface provided by deflecting the upper surface of the flow cell downward to the lower surface of the flow cell, creating a thin film of molecules confined within the focal depth of the microscope. 
     
     
         40 . The method of  claim 33 , wherein the sample measurement surface and/or the curved surface comprises surface features. 
     
     
         41 . The method of  claim 33 , wherein the sample measurement surface and/or the curved surface are chemically functionalized. 
     
     
         42 . A system for analyzing a molecule, comprising:
 a sample measurement zone formed by positioning a curved surface tangent to or in contact with a planar surface, at a point or along a line, wherein the sample measurement zone confines the sample of molecules to sub focal depth thicknesses allowing the molecules to be imaged within the entire sample measurement zone.   
     
     
         43 . The system of  claim 42 , wherein the imaging device is compatible with all types of optical microscopy. 
     
     
         44 . The system of  claim 42 , wherein the curved surface comprises a convex or cylindrical lens. 
     
     
         45 . The system of  claim 42 , wherein the curved surface can contain additional features and can be chemically functionalized. 
     
     
         46 . The system of  claim 42 , wherein the sample measurement zone comprises a flow cell for receiving a sample to measured, said flow cell comprising upper and lower sheet spaced apart initially by a distance defined by the thickness of side walls. 
     
     
         47 . The system of  claim 46 , further comprising a curved surface, positioned above the flow cell, for reversibly pushing the upper surface of the flow cell downward into contact with the lower surface of the flow cell, to form the sample measurement zone whose thickness is sub-focal depth. 
     
     
         48 . The system of  claim 42 , further comprising one or more of imaging and image processing software and device-control software. 
     
     
         49 . A method for analyzing a molecule, comprising:
 applying a liquid sample containing molecules to be measured to a sample measurement zone, the sample measurement zone having a material positioned tangent to a planar surface at a point or line of contact to confine the sample to sub focal depth thicknesses;   subjecting the sample to imaging by optical microscopy; and   performing optical analysis to obtain information characteristic of the molecules.   
     
     
         50 . The method of  claim 49 , wherein the confining walls of the measurement zone are curvilinear. 
     
     
         51 . The method of  claim 49 , further comprising:
 determining the location of the intensity relative to the point of contact, wherein the analysis of the spatial intensity profile is used to determine molecular size and shape.   
     
     
         52 . A method for detecting size of a molecule, comprising:
 applying a liquid sample containing molecules to be measured to a sample measurement surface;   contacting the sample measurement surface with a curved surface positioned tangent to the sample measurement surface at a point or line of contact, said curved surface varies in a predetermined and understood manner from the point or line of contact to a displaced position relative to the point or line of contact;   subjecting the sample to imaging to identify a region where sample is present; and   analyzing the spatial profile of the intensity of the sample to determine the molecular size and shape.