View source for Patent US 10,908,144

{{Short description|United States patent on sliding stacks of nanopores}}
{{Infobox patent
| title = Stacks of coaligned nanopores and fabrication and uses thereof
| image = Patent_US_10908144_claim_1_diagram.svg
| caption = The arrangement of claim 1, drawn for this article: three membranes of different thickness, each with a hole. Sliding the middle membrane narrows the passage, and sliding it further closes it.
| number = US 10,908,144 B2
| office = United States Patent and Trademark Office
| inventor = Stanley Kent Kemmish, Jr.
| priority = May 9, 2017
| filed = May 9, 2018
| granted = February 2, 2021
| lapsed = February 2, 2025 (maintenance fee unpaid)
| status = Expired, fee related
| classification = G01N 33/48721 (investigating macromolecules by translocation through nanopores)
| claims = 16 (3 independent)
| url = [https://patents.google.com/patent/US10908144B2/en Google Patents]
}}

'''US Patent 10,908,144''', titled "Stacks of coaligned nanopores and fabrication and uses thereof", is a United States patent granted on February 2, 2021, to [[Kent Kemmish]], the founder of [[Molecular Reality Corporation]]. Its subject is a stack of thin membranes, each with a hole. When one membrane slides sideways, its hole moves out of line with the others, and the channel through the stack narrows, changes shape or closes. The company calls the principle [[sliding occlusion]] and the resulting adjustable pore a [[juxtapore]].<ref name="patent">{{cite web |url=https://patents.google.com/patent/US10908144B2/en |title=US10908144B2: Stacks of coaligned nanopores and fabrication and uses thereof |website=Google Patents |access-date=2026-10-25}}</ref>

Kemmish filed the application on May 9, 2018, one year to the day after a provisional application, and it was published that November. The patent lapsed on February 2, 2025, when its first maintenance fee went unpaid. In 2026 Kemmish wrote that he no longer described the company in terms of its "IP portfolio" and that he "never believed that biotech should run on intellectual property".<ref name="patent" /><ref name="overview-post">{{cite web |title=2022 sci-tech overview |author=Kemmishtree |website=EQBio-OS |date=2026-03-28}}</ref>

== Background ==
A conventional [[solid-state nanopore]] is made once, at one size. The patent's background section lists the consequences: fixed pores detect only "molecules that are similarly sized", and they "suffer from both corrosion and clogging". It also gives a sense of the stakes: "Billions of dollars and decades of effort have been spent on developing sensing/sorting capabilities based on passing analytes through nanometer scale holes".<ref name="patent" />

Adjustable pores were not new. Among the six earlier documents the patent cites is an application filed by Agilent Technologies on October 30, 2001, for an "adjustable nanopore, nanotome, and nanotweezer", in which a sharp corner of a hole in one flat substrate is brought near the edge of a hole in another, so that their overlap forms a triangular aperture whose area piezoelectric positioners can change. It was granted as US 6,706,203 in 2004.<ref name="agilent">{{cite web |url=https://patents.google.com/patent/US6706203B2/en |title=US6706203B2: Adjustable nanopore, nanotome, and nanotweezer |website=Google Patents |access-date=2026-10-25}}</ref> Kemmish's description states what it considers new: "A major novel insight of the invention is the idea of moving and juxtaposing three or more layers relative to each other", and in particular "the use of three or more layers rather than only two in order to usefully affect both the longitudinal and lateral volumetric dimensions of the stacked passage."<ref name="patent" />{{efn|The description says that particle transit occurs "when openings in a separate layer or layers are juxtaposed by relative motion". The company's later name for its pores, juxtapore, is defined in its 2026 guide as "a pore formed by two surfaces sliding alongside each other".<ref name="faq">{{cite web |url=https://molecularreality.com/FAQ |title=Keltar's Field Guide to Molecular Reality |publisher=Molecular Reality Corporation |date=August 2026}}</ref>}}

== Claims ==
The patent has 16 claims. Three of them stand alone, and the other thirteen add detail to one of the three.<ref name="patent" />

;Claim 1, the stack
:"A stack of at least three longitudinally aligned nanopores in an equivalent number of stacked solid membranes that are free to move laterally such that moving one or more of the membranes changes the longitudinal alignment of the nanopores, thus modifying the dimensions and volumetric shape of the passage through the stacked membranes, wherein at least two of the stacked solid membranes have different thickness."
In plain terms: three or more membranes lie flat on one another, each with a hole, and the holes line up to make a channel. Pushing one membrane sideways moves its hole out of line, which narrows or reshapes the channel. At least two of the membranes must differ in thickness. Claims 2 to 7 add materials and shapes: one membrane made of atomically thin sheets; a list of seven plastics that includes "polytetralluoroethylene"{{sic}}; nine inorganic materials, from silicon to glass; a metal membrane; and holes of different lengths and widths.<ref name="patent" />

;Claim 8, the method of making
:Stack the membranes first, then form "one or more vias through the entire thickness of the stacked solid membranes".
Because one hole is drilled through the whole stack, the holes start out in line with one another. Claim 9 names ten ways to drill it, from ion-beam sculpting and [[controlled dielectric breakdown]] to "small hole EDM", "direct mechanical drilling" and "photothermal melting of gold nanorods". Claim 10 covers a membrane that slides far enough for its solid part to cover the hole next to it completely, which makes the pore a shutter.<ref name="patent" />

;Claim 11, the method of sensing
:Adjust the stack mechanically, pass molecules through it, and measure "changes that occur as a result of the molecules passing through and interacting with the stack of nanopores".
Dependent claims name what is measured: the [[ionic current]], read electronically or optically through fluorescent dyes that respond to ions; a tunneling current through the membranes; or images of fluorescent molecules in transit.<ref name="patent" />

Both the device claims and the sensing claims require at least three membranes, of which two differ in thickness; the fabrication claim requires only "a plurality".<ref name="patent" />

== Description ==
Beyond the claims, the description proposes opening the passage wide to catch a molecule and narrowing it once a weak signal shows the molecule has arrived, which "largely solves the problem of 'idle pores' in multipore arrays"; slowing single strands of DNA to read each base several times; restoring a working geometry after the edges of a pore corrode; and freeing a clog by making the stack "open, shut, or vibrate", or by widening it and using the space beside the debris as a new pore. It suggests cutting DNA by closing the passage, "analogous to the action of a guillotine", and claims a range "from single atoms up to entire cells with a single sensing device".<ref name="patent" /> One embodiment sorts gas molecules by speed: a tunneling current times each particle's transit and opens a second passage further along, "so that only particles of a certain speed are collected in a third chamber."<ref name="patent" />{{efn|In [[Maxwell's demon|Maxwell's thought experiment]] of 1867, from which demonpore, inc. took its name, a small being opens and closes a door between two chambers so that only fast molecules pass one way.}}

All four figures show stacks of four pores. The first is drawn with a molecule that "could non-limitingly represent a large virus approximately 300 nanometers at its widest point", and the text adds that "none of the figures present in this disclosure are intended to show scale accurately in either absolute or relative terms."<ref name="patent" />

=== Best mode ===
In its last section the patent sets out the inventor's preferred way of building the device. It needs two three-axis nanopositioners with at least 10 micrometers of travel, a patch clamp amplifier from "Elements, Inc.", a fluid cell and 1 M [[potassium chloride]]. Three squares of many-layer graphene are mounted in three nested frames, and the positioners push two of the frames through "rigid, sharp metallic materials": "we have found that 0.131″ framing nails serve this purpose nicely." The hole through all three layers is then made with a 9 V battery, applied in pulses of about ten seconds with the current checked in between, until it rises. The amplifier has to be disconnected during the pulses, because otherwise "the process could damage the amplifier". After that, moving the top two frames changes the shape of the passage.<ref name="patent" />{{efn|Since May 2026 the company has streamed live current from an [[EDR4]], an amplifier made by [[Elements srl]].<ref name="faq" />}}

== History ==
{| class="wikitable"
|+ Events in the patent record<ref name="patent" />
! Date !! Event
|-
| May 9, 2017 || Provisional application 62/503,340 filed
|-
| May 9, 2018 || Application 15/975,764 filed by the inventor, with small-entity status
|-
| November 15, 2018 || Application published as US 2018/0328909 A1
|-
| January 6, 2020 || First non-final office action mailed
|-
| July 17, 2020 || Second non-final office action mailed
|-
| December 31, 2020 || Issue fee received
|-
| February 2, 2021 || Patent granted as US 10,908,144 B2
|-
| September 23, 2024 || Maintenance fee reminder mailed
|-
| February 2, 2025 || Patent expired for failure to pay the maintenance fee (recorded March 10, 2025)
|}

A United States patent stays in force only if maintenance fees are paid at three and a half, seven and a half and eleven and a half years after issue, with a grace period of six months at a surcharge; a fee still unpaid at the end of the grace period ends the patent's rights.<ref name="uspto">{{cite web |url=https://www.uspto.gov/patents/maintain |title=Maintain your patent |publisher=United States Patent and Trademark Office |access-date=2026-10-25}}</ref> The first fee for this patent fell due in August 2024, the grace period ran out on February 2, 2025, and the patent expired that day. The Agilent patent it cites had lapsed in 2008, also at its first maintenance fee.<ref name="patent" /><ref name="agilent" /> A comment in the company's website code records that the patent "lapsed for non-payment of the 3.5-year maintenance fee; the page says so rather than presenting it as in force."<ref name="records">{{cite web |title=Company records |publisher=Molecular Reality Corporation |date=October 2026}}</ref> The company's guide, written in August 2026, describes the idea as having "a published patent behind it, US10908144, which any curious reader can look up."<ref name="faq" />

== The inventor's later view ==
In December 2022 the company described sliding occlusion as "our own patented approach to translocation control" and said it was "eager to extend this work and numerous variants in our own IP portfolio to the nanometer scale".<ref name="overview-post" /> When Kemmish republished that document in March 2026, he wrote:

{{Quote|I don't pitch the project anymore with any reference to 'our IP portfolio'. I never believed that biotech should run on intellectual property, but I was pandering. I have more battle scars now, and am willing to pay the price to ecrasez l'infame|Kent Kemmish|"2022 sci-tech overview" (2026)<ref name="overview-post" />}}

The thing to be crushed, in the same sentence, was the part of the biotechnology industry that he described as hoarding cancer patients' data.<ref name="overview-post" /> The company's role-playing game, [[Epic Quest Bio]], had listed two patent quests, both later switched off: "Patent prosecution", worth 4,000 [[Experience points (Epic Quest Bio)|XP]], and "Patent production (anti-trolling)", worth 5,000, whose task was to "Come up with ideas and make public-domain-assigned patents out of them".<ref name="quests">{{cite web |title=Quests |website=EQBio-OS |publisher=Molecular Reality Corporation |access-date=2026-10-25}}</ref> In February 2026 the company's website said that "our schematics and protocols will all become public domain", and in October 2026 it released the design of the [[MR1 Nanopore Reader]] under the [[GNU Affero General Public License]], then placed it in the public domain under CC0 1.0 five days later.<ref name="records" /><ref name="github">{{cite web |url=https://github.com/EpicQuestBio/MR1 |title=MR1 Nanopore Reader |website=GitHub |date=2026-10-16}}</ref><ref name="cc0">{{cite commit |repo=EpicQuestBio/MR1 |hash=a52fc0b |date=October 21, 2026 |message=Relicense project to Public Domain under CC0 1.0 Universal (CC0-1.0)}}</ref>

== Reception ==
''Signal & Noise'' discussed the patent in "Can a Hole That Slides Read a Molecule?", setting the sliding pore beside the [[Coulter counter]] and the stretchable pores of [[tunable resistive pulse sensing]], and ''Brownian Business Daily'' noted the grant and the lapse in a piece on the company's first ten years.<ref name="p5">{{cite news |title=Can a Hole That Slides Read a Molecule? |work=Signal & Noise |author=Lenora Ashgrove |date=2026-10-08 |url=/press/signal-noise/2026/10/08/sliding-holes}}</ref><ref name="p4">{{cite news |title=Ten Years of Hardware on About $1.6 Million |work=Brownian Business Daily |author=Harriet Quill |date=2026-09-30 |url=/press/brownian/2026/09/30/ten-years-on-a-budget}}</ref> Google Patents listed no later patent citing it as of October 2026.<ref name="patent" />

== See also ==
* [[Mechanical nanopore]]
* [[Ping-pong sensing]]
* [[Nanopore fabrication]]
* [[Tunable resistive pulse sensing]]

== Notes ==
{{Notelist}}

== References ==
{{Reflist}}

== External links ==
* [https://patents.google.com/patent/US10908144B2/en US 10,908,144 B2] at Google Patents

{{Molecular Reality}}
{{Nanopores}}

[[Category:Molecular Reality Corporation]]
[[Category:United States patents]]
[[Category:Nanopores]]