# US 2010/0167946 A1 · Photonic biosnesor arrays > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0167946 A1 - Document ID: US20100167946A1 - Status: Published application - Kind: A1 - Application number: 12/531,814 - Filed: 2008-03-19 - Published: 2010-07-01 - Earliest claimed: 2007-03-23 - Assignees: Attomarker Limited - Inventors: Andrew Mark Shaw; Rouslan Vladamir Olkhov; William Leslie Barnes - Web page: https://patentgrep.com/patent/US20100167946A1 ## CPC - G01N 21/554: {detecting the surface plasmon resonance of nanostructured metals, e.g. localised surface plasmon resonance} - B82Y 15/00: Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - G01N 21/211: {Ellipsometry (optical thickness measurement G01B11/06)} - G01N 21/253: {for batch operation, i.e. multisample apparatus (analytical automats G01N35/00)} - G01N 33/54313: {the carrier being characterised by its particulate form} - G01N 33/54373: {involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings} - G01N 33/553: Metal or metal coated - Y10T 436/25: including sample preparation - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract This invention relates to photonic biosensor arrays in particular employing plasmon resonance based sensing, and to methods and apparatus for reading such arrays. A biosensor array for plasmon resonance-based sensing of a plurality of different biological targets simultaneously, the array comprising a transparent substrate having a surface bearing a plurality of assay spots for plasmon resonance sensing, each of said assay spots comprising a discrete metallic island, a said metallic island comprising a plurality of metallic nanoparticles to which are attached functionalising molecules for binding to a said biological target, different said islands bearing different said functionalising molecules for binding to different ones of said biological targets, and wherein total internal reflection of light at said surface at a wavelength at or near a said plasmon resonance results in scattering of said light away from said surface, said scattering being modulated by said binding of said biological targets. ## Claims ### Claim at position 1 1-40. (canceled) ### Claim 41 A biosensor array for Plasmon resonance-based sensing of a plurality of different biological targets simultaneously, the array comprising a transparent substrate having a surface bearing a plurality of assay spots for Plasmon resonance sensing, each of said assay spots comprising a discrete metallic island, a said metallic island comprising a plurality of metallic nanoparticles to which are attached functionalising molecules for binding to a said biological target, different said islands being different said functionalising molecules for binding to different ones of said biological targets, and wherein total internal reflection of light at said surface at a wavelength at or near a said plasmon resonance results in scattering of said light away from said surface, said scattering being modulated by said binding of said biological targets. ### Claim 42 (depends on 1) A biosensor array as claimed in claim 1, wherein said metallic nanoparticles have at least one dimenstion of less than 30 nm, and comprise rod-like nanoparticles. ### Claim 43 (depends on 1) A biosensor array as claimed in claim 1, wherein said nanoparticles include nanoparticles forming an optical antenna for said light, wherein a said optical antenna comprises an adjacent pair of nanoparticles having a generally rod-like or triangular shape, and having adjacent ends separated by a gap of less than 100 nm, preferably less than 50 nm, said nanoparticles having physical lengths which are resonant for a said plasmon resonance at substantially the same optical wavelength. ### Claim 44 (depends on 1) A biosensor array as claimed in claim 1, further comprising at least one control spot substantially lacking said functionalising molecules, and wherein said control spot comprises an array of metallic elements configured to produce an interference or fringe pattern when said control spot is viewed. ### Claim 45 (depends on 1) A biosensor array as claimed in claim 1, wherein said transparent substrate is configured as a Dove prism, and includes an edge or grating optical coupling for coupling said light into an edge of said transparent substrate of said array to waveguide said light within a thickness of said substrate. ### Claim 46 (depends on 1) A biosensor array as claimed in claim 1, wherein said metallic nanoparticles comprise gold nanoparticles, and wherein said different functionalising molecules are attached to said metallic nanoparticles using the same ligand. ### Claim 47 (depends on 1) A method of using the biosensor array of claim 1 for a plasmon resonance-based sensing of a plurality of different biological targets simultaneously, the method comprising: coupling light of at least one wavelength into said biosensor array such that total internal reflection of said light at said surface generates an evanescent wave field which excites plasmons in said functionalised metallic nanoparticles and scatters said light; flowing a fluid carrying a plurality of said biological targets for analysis over said array; imaging said scattered light from said array to generate image data for said biological targets carried by said fluid; and analyzing said image data to determine levels of said biological targets carried by said fluid. ### Claim 48 (depends on 7) A method as claimed in claim 7, wherein said imaging of said scattered light comprises imaging said array from a side opposite to a side of said array being said assay spots. ### Claim 49 (depends on 7) A method as claimed in claim 7, wherein said imaging is performed in real-time to follow binding kinetics of said biological targets carried by said fluid, and wherein said analysing comprises determining time variations of binding of said different targets to said different functionalising molecules; and further comprising matching said time variations to one or more pathological conditions associated with said biological targets carried by said fluid. ### Claim 50 (depends on 7) A method as claimed in claim 7, wherein said light comprises light of at least two different wavelengths one to either side of said plasmon resonance, and wherein said analysing includes forming a ratio of signals at said two different wavelengths in said image data. ### Claim 51 (depends on 7) A method as claimed in claim 7, wherein said analysing comprises comparing a signal from one of said assay spots with a signal from another of said assay spots to compensate for non-specific binding interactions. ### Claim 52 (depends on 7) A method as claimed in claim 7, wherein said analysing comprises controlling for a bulk refractive index of said fluid using a control spot substantially lacking said functionalising molecules, wherein said control spot is configured to form a diffraction or interference pattern in said imaged scattered light. ### Claim 53 (depends on 7) A method as claimed in claim 7, wherein said biosensor array has an open top onto which said fluid may be deposited, and one or more built-in semiconductor light sources configured to provide waveguided light within said transparent substrate of said array to excite said plasmons. ### Claim 54 (depends on 7) A method as claimed in claim 7, wherein said imaging comprises imaging dark-field scattered light through a back surface of said biosensor array. ### Claim 55 (depends on 1) A biosensor array as claimed in claim 1, wherein an apparatus for plasmon resonance-based sensing of a plurality of different biological targets, the apparatus comprising: means for coupling light of at least one wavelength into said biosensor array such that total internal reflection of said light at said surface generates an evanescent wave field which excites plasmons in said functionalised metallic nanoparticles and scatters said light; means for flowing a fluid carrying a plurality of said biological targets for analysis over said array; means for imaging said scattered light from said array to generate image data for said biological targets carried by said fluid; and means for analysing said image data to determine levels of said biological targets carried by said fluid. ### Claim 56 (depends on 55) A biosensor array as claimed in claim 55, wherein said means for imaging comprises means to image dark-field scattered light through a back surface of said array. ### Claim 57 (depends on 41) A biosensor array as claimed in claim 41, wherein an apparatus for reading a plasmon resonance sensing array for plasmon resonance-based sensing of a plurality of different biological targets, the array comprising a transparent substrate having a surface bearing a plurality of assay spots for plasmon resonance sensing, each of said assay spots comprising a discrete metallic island to which is attached functionalising molecules for binding to a said biological target, different said islands bearing different said functionalising molecules for binding to different ones of said biological targets, and wherein total internal reflection of light at said surface at a wavelength at or near a said plasmon resonance results in scattering of said light away from said surface, said scattering being modulated by said binding of said biological targets, the apparatus comprising: a light source to generate light at two different substantially monochromatic wavelengths; an optical coupling device to couple light from said light source into said sensing array; an imaging system to image light from said array at said two different wavelengths scattered by plasmon resonance in said metallic islands, and to generate image date; and an image analysis system coupled to said imaging system to receive said image data and to analyse said plasmon-resonance scattered light to determine levels of said different biological targets attached to said array. ### Claim 58 (depends on 17) An apparatus as claimed in claim 17, configured to determine said levels of said different biological targets attached to said array using light of two orthogonal polarisations. ### Claim 59 Apparatus for reading a plasmon resonance sensing array for plasmon resonance-based sensing of a plurality of different biological targets, the array comprising a transparent substrate having a surface being a plurality of assay spots for said plasmon resonance testing, the apparatus comprising: a light source to generate polarised light; a polarisation modulator to modulate a polarisation f said polarised light; an optical system to illuminate said array with said modulated polarised light to generate plasmons in said assay spots by total internal reflection of said polarised light; a detection system to detect an orientation of an elliptical polarisation of said totally internally reflected modulated polarised light; and an output to output a target sensing signal dependent on binding of a said biological target to a said functionalising molecule responsive to detection of a change in said elliptical polarisation orientation. ### Claim 60 (depends on 59) An apparatus as claimed in claim 59, wherein said polarisation modulator is pixellated for separate interrogation of said assay spots, and wherein said detection system is configured to enable separation of signals from different ones of said assay spots. ### Claim 61 (depends on 59) An apparatus as claimed in claim 59, configured to image dark-field scattered light through a black surface of said array. ### Claim 62 (depends on 1) A method of using the biosensor array of claim 1 for plasmon resonance-based sensing of different biological targets simultaneously, the method comprising: coupling light of at least one wavelength into said biosensor array such that total internal reflection of said light at said surface generates am evanescent wave field which excites plasmons in said functionalised metallic nanoparticles, said light comprising polarised light with polarisation modulation; detecting an orientation of an elliptical polarisation of totally internally reflected modulated polarised light; and outputting a target sensing signal responsive to binding of a said biological target to a said functionalising molecule dependent on detection of a change in said elliptical polarisation orientation. ### Claim 63 A biosensor array for plasmon resonance-based sensing, the array having a surface bearing a plurality of assay spots, each of said assay spots comprising a conducting material for plasmon resonance sensing, and wherein the array further comprises at least one control spot, said control spot bearing a pattern of conductive elements such that light emitted by plasmon resonance in said control spot exhibits a pattern of interference or fringes. ### Claim 64 (depends on 63) A biosensor array as claimed in claim 63, wherein said control spot comprises an array of said conductive elements. ### Claim 65 (depends on 63) A biosensor array as claimed in claim 63, wherein said array of conductive elements comprises a regular array of conductive elements with a pitch of between 100 nm and 1800 nm. ### Claim 66 (depends on 63) A biosensor array as claimed in claim 63, wherein said conductive elements comprise a pattern in a conductive metallic layer on a substrate of said array.