Thermo-Scientific patent6,628,382

“Liquid photometer using surface tension to contain sample”

Thermo-Scientific patent6,628,382

“Liquid photometer using surface tension to contain sample”

The NanoDrop is a simple, easy-to-use spectrophotometer for measuring DNA, RNA, and protein concentrations insmall volume samples.

Spectrophotometers measure absorbance

Beer’s Law dictates absorption rate proportional to number of particles in optical path

At 260 nmDouble-stranded DNA has extinction coefficient ε260 = 0.020 (ug/ml)-1cm-1

Single-stranded DNA and RNA have extinction coefficient ε260 = 0.025 (ug/ml)-1cm-1

pathlength

Spectrophotometers measure absorbance

Beer’s Law dictates absorption rate proportional to number of particles in optical path

At 260 nmDouble-stranded DNA has extinction coefficient ε260 = 0.020 (ug/ml)-1cm-1

Single-stranded DNA and RNA have extinction coefficient ε260 = 0.025 (ug/ml)-1cm-1

The absorbance A260 = ε260 x (path length) x (concentration)

A260

A280

Ratio gives measurement of protein contamination

pathlength

McMillan et al‘402, 1990

State of the field prior

Samples (often >50 ul) added to cuvettes

Surface tension,internal reflectionof ~1 ul dropletbetween 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)

sampleof ~ 1ul plunger

pin

allen head-cap screw

optical fibercarrying lightfrom source

optical fibercarrying lightto 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

Loadingposition

Compressionposition

Measurementposition

fixedpin

solenoid

plunger

NanoDrop

1 ul sample

sample columnof path-lengthoptimized forsample

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 …

0.2-2 mm

Loadingposition

Compression/Measurementposition

Spec-2-Go

interchangeablepin

1 ul sample

0-1 ul sample,depending on pin size

pin stop

0.2-2 mm

LITERAL INFRINGEMENTThere is a one-to-one correspondence between the Spec-2-Go and theelements of Claim 1 of the ‘382 patent

NanoDrop position 1an 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 bothanvils)

NanoDrop position 2an 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 3an 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)

COMPRESSIONPOSITION

MEASUREMENTPOSITION

COMPRESSION/MEASUREMENTPOSITION

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 element NanoDrop™ Spec2go™

Function Accesses sample loading, compression, and measurement positions

Accesses sample loading, compression, and measurement positions

Way Anvils are moved to achieve loading, compression, and measurement of sample

Anvils are moved to achieve loading, compression, and measurement of sample

Result Sample held by surface tension in column of sufficient path length for absorbance measurement

Sample held by surface tension in column of sufficient path length for absorbance measurement

Claim Element: Three positions

DOEClaim 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 element NanoDrop™ Spec2go™

Function Liquid drop from bottom surface wets and spreads upon upper surface

Liquid drop from bottom surface wets and spreads upon upper surface

Way Surfaces are brought close enough for wetting and spreading to occur

Surfaces are brought close enough for wetting and spreading to occur

Result Liquid mass on both surfaces is fused for a column to form

Liquid 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 element NanoDrop™ Spec2go™

Function Sample forms a column of liquid between two surfaces

Sample forms a column of liquid between two surfaces

Way One 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

Result A column of liquid is formed with sufficient path length for absorbance measurement

A 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