Thermo-Scientific patent 6,628,382 “Liquid photometer using surface tension to contain sample”

Thermo-Scientific patent 6,628,382 “Liquid photometer using surface tension to contain sample” The NanoDrop is a simple, easy-to- use spectrophotometer for measuring DNA, RNA, and protein concentrations in small volume samples.

Spectrophotometers measure absorbance Beer’s Law dictates absorption rate proportional to number of particles in optical path At 260 nm Double-stranded DNA has extinction coefficientε 260 = (ug/ml) -1 cm -1 Single-stranded DNA and RNA have extinction coefficientε 260 = (ug/ml) -1 cm -1 path length

Spectrophotometers measure absorbance Beer’s Law dictates absorption rate proportional to number of particles in optical path At 260 nm Double-stranded DNA has extinction coefficientε 260 = (ug/ml) -1 cm -1 Single-stranded DNA and RNA have extinction coefficientε 260 = (ug/ml) -1 cm -1 The absorbance A260 = ε 260 x (path length) x (concentration) A 260 A 280 Ratio gives measurement of protein contamination path length

McMillan et al ‘402, 1990 State of the field prior Samples (often >50 ul) added to cuvettes Surface tension, internal reflection of ~1 ul droplet between rigid fibers oceanoptics.com SpectroPippeter from Ocean Optics aspirates ~ 2 ul fluid into small channel for measurement ~1 cm path-length

permanent magnet solenoid (with actuator) sample of ~ 1ul plunger pin allen head-cap screw optical fiber carrying light from source optical fiber carrying light to detector anvil/pedestal NanoDrop

1. A photometric or spectrophotometric apparatus wherein -a sample in the form of a liquid drop is contained by surface tension forces between two planar surfaces, one containing --a photometric or spectrophotometric source and the other --a photometric or spectrophotometric detector and -an optical path is established through the sample between the two surfaces said apparatus comprising: [A] first and second anvil surfaces -at least one being moveable relative the other to any one of three positions; [B] an adjustable sample loading position so selected that -the at least one moveable surface and -the other surface are so remotely spaced that --a liquid drop can be placed on the first surface; [C] an adjustable sample compression position so selected that -the surfaces are --opposed and --substantially parallel and --proximally spaced so that ---the liquid ----wets and ----spreads upon both surfaces; [D] an adjustable sample measuring position so selected that -the opposed substantially parallel surfaces are spaced apart to --pull the sample into a column wherein --it is contained by the surface tension thereby ----providing an optical path for a -----photometric or -----spectrophotometric measurement. CLAIM 1 ELEMENTS AT ISSUE

Loading position Compression position Measurement position fixed pin solenoid plunger NanoDrop 1 ul sample sample column of path-length optimized for sample an adjustable sample loading position so selected that … a liquid drop can be placed on the first surface; an adjustable sample compression position so selected that … the liquid wets and spreads upon both surfaces; an adjustable sample measuring position so selected that the opposed substantially parallel surfaces are spaced apart to pull the sample into a column … mm

Loading position Compression/Measurement position Spec-2-Go interchangeable pin 1 ul sample 0-1 ul sample, depending on pin size pin stop mm

LITERAL INFRINGEMENT There is a one-to-one correspondence between the Spec-2-Go and the elements of Claim 1 of the ‘382 patent NanoDrop position 1 an adjustable sample loading position so selected that -the at least one moveable surface and -the other surface are so remotely spaced that --a liquid drop can be placed on the first surface; Spec-2-Go position 1 (open arms and sample loading to both anvils) NanoDrop position 2 an adjustable sample compression position so selected that -the surfaces are --opposed and --substantially parallel and --proximally spaced so that ---the liquid ----wets and ----spreads upon both surfaces; NanoDrop position 3 an adjustable sample measuring position so selected that -the opposed substantially parallel surfaces are spaced apart to --pull the sample into a column wherein ---it is contained by the surface tension thereby ----providing an optical path for a -----photometric or -----spectrophotometric measurement. Spec-2-Go position 2 (compression/measuring position)

COMPRESSION POSITION MEASUREMENT POSITION COMPRESSION/MEASUREMENT POSITION NANODROP SPEC-2-GO an adjustable sample measuring position so selected … to pull the sample into a column

“Adjustable position” Preset freedom of movement: (A) Claim 1: “an adjustable sample compression position” (uses anvils as stops for the NanoDrop arm-movements) (B) Claim 21: “an adjustable stop regulates the spacing between the two surfaces when the solenoid plunger is depressed” Movement during measurement: (A) Claim 25: “adjusting the distance between those two surfaces such that the sample is drawn into a column”

DOE DOE elementNanoDrop™Spec2go™ FunctionAccesses sample loading, compression, and measurement positions WayAnvils are moved to achieve loading, compression, and measurement of sample ResultSample held by surface tension in column of sufficient path length for absorbance measurement Claim Element: Three positions

DOE Claim Element: Sample compression position … the liquid [drop] wets and spreads upon both surfaces

1. A photometric or spectrophotometric apparatus wherein -a sample in the form of a liquid drop is contained by surface tension forces between two planar surfaces, one containing --a photometric or spectrophotometric source and the other --a photometric or spectrophotometric detector and -an optical path is established through the sample between the two surfaces said apparatus comprising: [A] first and second anvil surfaces -at least one being moveable relative the other to any one of three positions; [B] an adjustable sample loading position so selected that -the at least one moveable surface and -the other surface are so remotely spaced that --a liquid drop can be placed on the first surface; [C] an adjustable sample compression position so selected that -the surfaces are --opposed and --substantially parallel and --proximally spaced so that ---the liquid ----wets and ----spreads upon both surfaces; [D] an adjustable sample measuring position so selected that -the opposed substantially parallel surfaces are spaced apart to --pull the sample into a column wherein --it is contained by the surface tension thereby ----providing an optical path for a -----photometric or -----spectrophotometric measurement. CLAIM 1

DOE DOE elementNanoDrop™Spec2go™ FunctionLiquid drop from bottom surface wets and spreads upon upper surface WaySurfaces are brought close enough for wetting and spreading to occur ResultLiquid mass on both surfaces is fused for a column to form Claim Element: Sample compression position … the liquid [drop] wets and spreads upon both surfaces

DOE DOE elementNanoDrop™Spec2go™ FunctionSample forms a column of liquid between two surfaces WayOne droplet on bottom surface is pulled by surface tension at the liquid-solid interface Two droplets pull on one another by surface tension at the liquid- liquid interface ResultA column of liquid is formed with sufficient path length for absorbance measurement Claim Element: Sample measuring position … [surfaces] pull the sample into a column

Figures 3a, 3b, 3c, and 3d