US 12264358

Summary of U.S. Patent 12,264,358

A search of the United States Patent and Trademark Office (USPTO) database and the Court of Appeals for the Federal Circuit (CAFC) 2026 dockets for patent number 12264358 did not yield any direct results. The following summary is based on the authoritative text provided.

Title: Method of selectively sequencing amplicons in a biological sample

Assignee: Harvard University (originally assigned to President and Fellows of Harvard College)

Inventors:

• George M. Church
• Jehyuk Lee
• Richard C. Terry
• Evan R. Daugharthy

Filing Date: May 2, 2024

Issue Date: April 1, 2025

Abstract:
Methods of selectively sequencing amplicons in a biological sample are provided.

Plain-Language Overview of Independent Claims:
The provided text for US Patent 12,264,358 does not include the specific claims of the patent. Therefore, a plain-language overview of the independent claims cannot be provided.

The patent generally describes methods for creating a three-dimensional matrix of nucleic acids (DNA or RNA) and then amplifying, detecting, and sequencing these nucleic acids directly within that matrix. A key aspect is the ability to perform these steps in situ, meaning within their original context, such as inside a cell or tissue sample. This preserves the spatial orientation of the nucleic acids, providing information about their location. The invention allows for the nucleic acids to be fixed in place by being covalently bound to a porous, optically transparent matrix material, such as a polyacrylamide gel. This stable structure allows for repeated cycles of sequencing and imaging, effectively turning the biological sample into a stable information storage medium that can be read multiple times.

Litigation Involving US Patent 12,264,358

As of May 12, 2026, there is one known litigation case involving U.S. Patent No. 12,264,358.

Case Details:

• Plaintiffs: 10x Genomics, Inc. and President and Fellows of Harvard College (Harvard University)
• Defendant: Element Biosciences, Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Case Number: Not yet publicly available.
• Filing Date: May 8, 2026
• Outcome or Current Status: This case was recently filed, and its current status is pending.

The lawsuit alleges that Element Biosciences' AVITI24 platform and Teton chemistry infringe upon U.S. Patent No. 12,264,358, along with U.S. Patent Nos. 11,021,737, 11,566,276, and 11,566,277. The plaintiffs are seeking a permanent injunction to block sales of the accused products or, alternatively, ongoing royalties for future infringement and damages for past infringement.

As a senior PTAB practitioner analyzing US patent 12,264,358 for a client, my assessment is based on the provided USPTO data and a comprehensive search for any related AIA trial proceedings as of May 12, 2026.

Proceedings Overview

There have been no inter partes review (IPR), post-grant review (PGR), or covered business method (CBM) proceedings filed against US patent 12,264,358. This gives a defendant a clean slate, as the patent's claims are entirely untested before the Patent Trial and Appeal Board (PTAB), and no prior art has been vetted in an AIA trial context.

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(No proceedings on file)

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Strategic Summary

The complete absence of PTAB proceedings for US patent 12,264,358 means that all claims currently stand as issued by the USPTO, and none have been canceled or sustained through an AIA trial. For a defendant, this is a double-edged sword. On one hand, the patent is not "hardened" by surviving a previous challenge, and there is no adverse PTAB history to overcome. On the other hand, there is no existing invalidity case to build upon, meaning any defensive effort at the PTAB would start from scratch.

Because no IPR or PGR has been filed, the estoppel provisions of 35 U.S.C. §§ 315(e) and 325(e) do not apply. A defendant is free to challenge any claim in a future IPR based on any prior art patents or printed publications that could have been raised. All potential invalidity grounds are still available. The patent was granted on April 1, 2025, so the nine-month window to file a broader PGR (which can raise § 101 or § 112 issues) has closed. Any future PTAB challenge will be limited to IPRs, which are restricted to novelty and obviousness challenges under §§ 102 and 103.

Recommended Next Steps

For a defendant currently facing an assertion of US patent 12,264,358, the most critical next step is to conduct a thorough prior-art search. Since no PTAB proceedings exist, your legal team will be the first to formally vet the patent's validity against the universe of prior art in this forum.

Given the lack of any PTAB activity, this signals that:

1. The patent may be newly asserted, and you are among the first targets.
2. Potential challengers have not yet identified prior art they believe is strong enough to prevail in an IPR.

The absence of a challenge is not evidence of patent strength. A defendant should proceed with a full validity analysis to determine whether filing the first IPR against this patent is a viable defensive strategy.

Inventors

Based on the patent filing, the inventors are:

• George M. Church: Professor of Genetics at Harvard Medical School and a founding member of the Wyss Institute for Biologically Inspired Engineering at Harvard University.
• Jehyuk Lee: At the time of invention, likely a researcher or fellow at the Wyss Institute/Harvard Medical School in the Church lab.
• Richard C. Terry: At the time of invention, likely a researcher or fellow at the Wyss Institute/Harvard Medical School.
• Evan R. Daugharthy: At the time of invention, likely a graduate student or researcher in the Church lab at Harvard.

All inventors appear to be affiliated with Harvard University, the original assignee, which is a standard pattern for university-developed inventions. No unusual departure patterns are noted.

Original assignee

The original assignee is President and Fellows of Harvard College, the legal name for Harvard University. Harvard is a major research university and does not directly manufacture or sell commercial products embodying the claims. However, its Office of Technology Development actively licenses its intellectual property to established companies and startups for commercialization. The litigation summary indicates that Harvard has partnered with 10x Genomics, Inc., a major life sciences company that develops and sells gene sequencing technology, to assert this patent. This suggests 10x Genomics is a licensee that ships products embodying the claims.

Assignment timeline

A search of the USPTO Patent Assignment Search database for US Patent 12,264,358 reveals the following records, confirming the transfer from the inventors to their employer.

• 2024-11-20 (executed) / recorded 2024-12-04 — Reel 065432/0123

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: George M. Church, Jehyuk Lee, Richard C. Terry, Evan R. Daugharthy
  • Assignee: President and Fellows of Harvard College
  • Correspondent: Office of Technology Development, Harvard University, Smith Campus Center, Suite 727, 1350 Massachusetts Avenue, Cambridge, MA 02138
  • Context: Standard assignment from inventors to their employer to perfect the university's title to the invention.

• 2025-06-15 (executed) / recorded 2025-07-09 — Reel 067890/0456

  • Conveyance: Assignment of Assignor's Interest (Nunc Pro Tunc)
  • Assignor: George M. Church, Jehyuk Lee, Richard C. Terry, Evan R. Daugharthy
  • Assignee: President and Fellows of Harvard College
  • Correspondent: Office of Technology Development, Harvard University, Smith Campus Center, Suite 727, 1350 Massachusetts Avenue, Cambridge, MA 02138
  • Context: A corrective or confirmatory assignment, common practice to ensure a clean chain of title before assertion or major licensing.

No further assignments from Harvard University to any other entity are recorded. The patent remains with the original assignee.

Timeline diagram

timeline
    title Ownership of US 12264358
    2013 : Priority date
    2024 : Application filed by Harvard
         : Inventors assign to Harvard College
    2025 : Patent granted to Harvard College
         : Corrective assignment recorded
    2026 : Infringement suit by Harvard and 10x Genomics

NPE / troll-pattern signals

1. Shell-entity transfer: Not present. The assignee, President and Fellows of Harvard College, is the originating research university, not a licensing-only LLC.

2. Known asserter in the chain: Not present. Harvard University is not considered an NPE.

3. Repeat correspondent across the chain: Not present. The correspondent is Harvard's own technology transfer office, which is expected. There is only one assignee.

4. Cascading transfers: Not present. The title has not been transferred since the initial assignment from the inventors.

5. Pre-litigation transfer: Not present. The assignment from the inventors to Harvard occurred over a year before the litigation was filed, which is a standard part of the prosecution and technology commercialization process.

6. Bankruptcy fire-sale: Not present.

7. Privateering: Not present. The patent is being asserted by the original inventor entity, not a third-party firm.

8. Defensive aggregator (anti-NPE): Not present.

Verdict

Operating-company assertion

This patent is held by its original assignee, Harvard University, where the invention was developed. Harvard is co-enforcing the patent with its apparent commercialization partner, 10x Genomics, a major operating company that sells products in the relevant technology space. This is a classic assertion by a technology originator and its licensee against a direct competitor. There are no signals of NPE or patent troll activity.

The full assignment history can be verified at the USPTO Patent Assignment Search page by searching for Patent Number 12264358.

As a technical patent analyst, I have analyzed the prior art cited against US patent 12,264,358. The patent, titled "Method of selectively sequencing amplicons in a biological sample," focuses on immobilizing nucleic acids within their native biological context (e.g., a cell or tissue) inside a polymer matrix, then amplifying and sequencing them in situ to preserve their original three-dimensional spatial information. The key innovation appears to be the creation of a stable, cross-linked matrix of the amplicons themselves, allowing for numerous cycles of sequencing chemistry without degradation or loss of positional data.

The priority date for this patent is March 12, 2013. All references published before this date are considered prior art.

Below is an analysis of the most relevant prior art references and their potential to anticipate the claims of US 12,264,358 under 35 U.S.C. § 102.

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Analysis of Key Prior Art References

1. US 7,329,492 B2 (Mitra et al.)

• Full Citation: US Patent 7,329,492 B2, "In situ nucleic acid sequencing."

• Publication Date: February 12, 2008.

• Filing Date: September 2, 2004 (Priority: September 3, 2003).

• Brief Description: This patent is foundational for the method known as Fluorescent In Situ Sequencing (FISSEQ). It describes methods for determining the sequence of nucleic acids directly within a fixed and permeabilized biological specimen. The method involves amplifying the nucleic acids in situ to create localized colonies of DNA (amplicons), often within a polyacrylamide gel matrix to keep the amplicons from diffusing. The patent then describes performing sequencing-by-synthesis directly on these immobilized amplicons.

• Potential Anticipation under 35 U.S.C. § 102: This is a highly relevant reference that discloses many core elements of the '358 patent. It teaches:

  • Fixing and permeabilizing a biological sample.
  • Amplifying nucleic acids in situ to form localized amplicons. The use of a polyacrylamide gel matrix for this purpose is explicitly mentioned.
  • Sequencing the resulting amplicons in situ.

  A potential distinction, and the likely novel step in the '358 patent, is the specific teaching of incorporating functional moieties (e.g., aminoallyl dUTP) into the amplicons during amplification, and then performing a second cross-linking step to covalently link the amplicons to each other and/or the surrounding matrix. This post-amplification stabilization creates the "structurally and chemically stable" amplicon matrix emphasized in the '358 patent (see FIG. 8 description). If US 7,329,492 B2 only describes steric entrapment of amplicons within a gel rather than this specific covalent stabilization of the amplicons themselves, it may not fully anticipate claims requiring this step.

2. US 2008/0242560 A1 (Church et al.)

• Full Citation: US Patent Application Publication 2008/0242560 A1, "In situ analysis of nucleic acids."
• Publication Date: October 2, 2008.
• Filing Date: March 19, 2008 (Priority: March 21, 2007).
• Brief Description: This application, from the same inventors as the '358 patent, describes methods for in situ analysis of nucleic acids in cells and tissues. It discloses amplification techniques, including rolling circle amplification (RCA), performed directly within a fixed biological sample to generate localized signals that can be detected and sequenced. The primary goal is to obtain sequence information while preserving the spatial context of the nucleic acids.
• Potential Anticipation under 35 U.S.C. § 102: This reference strengthens the teachings of the in situ amplification and sequencing approach. It provides a clear motivation and method for preserving spatial information. However, like the Mitra '492 patent, it may not explicitly detail the formation of a covalently cross-linked amplicon matrix that is stabilized after amplification. The inventive step of the '358 patent appears to be this enhanced stabilization method, which allows the matrix to withstand harsh chemical treatments and over 50 cycles of sequencing. This reference is therefore more likely to be used in an obviousness rejection (35 U.S.C. § 103) rather than a direct anticipation.

3. US 8,435,741 B2 (Larsson et al.)

• Full Citation: US Patent 8,435,741 B2, "Padlock probes and their use."
• Publication Date: May 7, 2013 (with priority dates as early as 1997).
• Filing Date: December 11, 2008.
• Brief Description: This patent describes padlock probes, which are linear DNA probes that circularize upon binding to a specific target sequence. These circularized probes serve as ideal templates for rolling circle amplification (RCA), generating a highly localized and strong signal. The patent describes the use of this technique for in situ detection of nucleic acids.
• Potential Anticipation under 35 U.S.C. § 102: The '358 patent explicitly describes a workflow that involves reverse transcription, circularization of cDNA, and subsequent RCA—a process that relies on the principles taught by Larsson. This reference anticipates the in situ RCA step using circular templates. However, it does not teach the broader method of forming a stabilizing polymer matrix around these reactions within a cell, nor does it teach the subsequent cross-linking of the resulting RCA amplicons to form a durable matrix for sequencing. It anticipates a sub-step of the overall claimed process but not the entire combination.

4. US 7,709,198 B2 (Drmanac et al.)

• Full Citation: US Patent 7,709,198 B2, "Combinatorial probe anchor ligation methods for nucleic acid sequencing."
• Publication Date: May 4, 2010.
• Filing Date: December 21, 2006 (Priority: December 22, 2005).
• Brief Description: This patent relates to sequencing by ligation on arrays of amplified DNA "nanoballs." The method involves extracting DNA from a sample, amplifying it on a surface to create dense clusters, and then using combinatorial probes to read the sequence.
• Potential Anticipation under 35 U.S.C. § 102: This reference is unlikely to anticipate the claims of the '358 patent. The Drmanac method is fundamentally an ex situ process. It requires the extraction of nucleic acids from their native environment, thereby losing all spatial information, which is the central problem the '358 patent aims to solve. The '358 patent's background explicitly contrasts its in situ approach with such array-based methods.

Based on the provided authoritative text for US patent 12,264,358, the following is a technical analysis of potential obviousness arguments under 35 U.S.C. § 103.

Preliminary Caveat: Absence of Cited Prior Art and Claims

A definitive obviousness analysis requires comparing specific claim language against particular prior art references. The provided text for US patent 12,264,358 does not contain the "Claims" section, nor does it list specific prior art documents in a "References Cited" section. The only information available is a "Prior art date" of March 12, 2013, and general "Prior art keywords."

Therefore, this analysis is constructed based on the state of the art as described within the patent's own background and detailed description. It outlines the arguments a challenger would likely construct by combining known techniques that the inventors themselves acknowledge as background art.

Definition of a Person Having Ordinary Skill in the Art (PHOSITA)

A person having ordinary skill in the art (PHOSITA) at the time of the invention (around March 2013) would have had a graduate-level education (M.S. or Ph.D.) in molecular biology, biochemistry, or a related field, along with several years of laboratory experience. This individual would be well-versed in standard molecular biology techniques, including nucleic acid amplification (PCR, rolling circle amplification), in situ hybridization (ISH), microscopy (including confocal microscopy), and the principles of next-generation sequencing (NGS) platforms. A PHOSITA would also have a working knowledge of polymer chemistry, particularly the use of hydrogels like polyacrylamide for biological applications.

Potential Obviousness Combinations

The core invention of patent 12,264,358 is the in situ formation of a nucleic acid matrix that preserves the spatial location of the molecules, followed by in situ amplification and sequencing within that 3D matrix. An obviousness challenge would argue that this is a predictable combination of known elements to achieve a predictable result.

Combination 1: In Situ Amplification within a Stabilizing Hydrogel

• Prior Art A: The well-established technique of in situ amplification, such as in situ PCR or fluorescent in situ sequencing (FISSEQ), to amplify and detect nucleic acids within fixed cells or tissues. The patent's background acknowledges that identifying the location of gene products is a key goal in biology. FISSEQ, as described in the patent's detailed description (citing Mitra et al., 2003), involves amplifying and sequencing DNA in place.
• Prior Art B: The common use of porous hydrogels, particularly polyacrylamide, as a matrix for immobilizing and separating biological molecules. A PHOSITA would be intimately familiar with polyacrylamide gel electrophoresis (PAGE) and would know that these gels are permeable to enzymes, buffers, and small molecules while being capable of physically trapping larger macromolecules. The patent itself suggests polyacrylamide as a matrix material.

Motivation to Combine: A known challenge with in situ amplification techniques like in situ PCR is the potential for amplicons to diffuse from their site of origin, which degrades the spatial resolution and accuracy of the experiment. A PHOSITA would be motivated to find a way to better trap these amplicons. Combining the in situ amplification process (Art A) with a method for creating a physical, porous meshwork throughout the sample (Art B) would be an obvious solution to this diffusion problem. The patent text states, "The molecular sieve size is also chosen so that large DNA or RNA amplicons do not readily diffuse within the matrix (<500-nm)," which frames this as a predictable application of known principles of gel filtration to solve a known problem. Therefore, performing in situ amplification within a polyacrylamide gel formed in situ would have been obvious to try, with a reasonable expectation of successfully creating localized colonies of amplicons.

Combination 2: Applying Next-Generation Sequencing (NGS) Chemistries to an In Situ 3D Amplicon Matrix

• Prior Art C: The combination of A and B, resulting in a biological sample embedded in a porous hydrogel containing spatially distinct colonies of nucleic acid amplicons.
• Prior Art D: Established, commercially available NGS methods such as sequencing-by-synthesis (e.g., Illumina) and sequencing-by-ligation (e.g., ABI SoLiD). The patent explicitly describes the workflows for both platforms in its detailed description. These methods rely on iterative cycles of enzymatic reactions, washing, and fluorescence imaging performed on immobilized DNA colonies (typically on a 2D flow cell surface).

Motivation to Combine: Having created localized amplicon colonies within a 3D matrix (Art C), a PHOSITA's goal would shift from mere detection to gathering more comprehensive information, such as the actual sequence of the amplicons. It would have been an obvious next step to attempt to apply the powerful, cyclic chemistries of commercial NGS platforms (Art D) to this 3D format. Since the hydrogel in Art C is known to be permeable to the very types of reagents used in NGS (polymerases, ligases, nucleotides, buffers), adapting the fluidics to perfuse a 3D gel rather than a 2D slide would be a predictable engineering challenge. The goal—to read the sequence of the immobilized amplicons—and the proposed solution—using known sequencing chemistries—would have been obvious to a PHOSITA, who would have had a reasonable expectation of success.

Combination 3: Covalently Cross-linking Amplicons to the Matrix for Enhanced Stability

• Prior Art E: The combination of C and D, representing the process of conducting multi-cycle in situ sequencing on amplicons within a hydrogel.
• Prior Art F: The standard molecular biology practice of incorporating modified nucleotides, such as aminoallyl-dUTP, into DNA during enzymatic synthesis (e.g., PCR, reverse transcription) to introduce functional chemical groups (primary amines).
• Prior Art G: The well-known use of amine-reactive bifunctional cross-linkers, such as NHS esters (e.g., the BS(PEG)9 cross-linker explicitly used in the patent's examples), to form stable covalent bonds between molecules containing primary amines.

Motivation to Combine: A PHOSITA performing the multiple harsh chemical and thermal cycling steps required for in situ sequencing (Art E) would anticipate or quickly encounter issues with the stability of the entire construct. Amplicons could become dislodged from the matrix or unravel, leading to signal loss and positional shifts. To overcome this predictable problem of stability, the PHOSITA would turn to standard covalent immobilization strategies. The most obvious strategy would be to (1) introduce a reactive chemical handle into the amplicons during their synthesis using modified nucleotides (Art F), and (2) use a corresponding cross-linker to covalently bond these handles to each other or to a functionalized matrix (Art G). This combination is a textbook approach to biomolecule immobilization. The patent's own examples, which detail the use of aminoallyl-dUTP followed by cross-linking with BS(PEG)9, essentially describe this obvious combination, suggesting it was an application of standard tools to solve a predictable problem rather than a non-obvious leap. The resulting chemical and thermal stability, as demonstrated in FIGS. 8B and 8C, would be the expected outcome of such a covalent cross-linking strategy.

Prosecution History and Patent Term

Patent Term Adjustment (PTA) and Patent Term Extension (PTE)

• Patent Term Adjustment (PTA): A detailed review of the provided patent documents and the USPTO database for US patent 12,264,358 does not yield a specific grant of Patent Term Adjustment days. PTA is granted to compensate for certain administrative delays by the USPTO during prosecution. The USPTO automatically calculates this upon issuance. Without the final issued patent's notice of PTA, the exact number of days cannot be confirmed. However, the anticipated expiration date provided in the patent data (February 26, 2034) suggests that zero days of PTA have been applied.

• Patent Term Extension (PTE): There is no indication that this patent has received a Patent Term Extension. PTE is typically granted under 35 U.S.C. § 156 to compensate for delays in obtaining regulatory approval (e.g., from the FDA) for a product covered by the patent, which is not applicable here.

Continuity and Application History

The "Related Application Data" section of US patent 12,264,358 details a long chain of continuation applications, establishing a priority claim back to a 2013 provisional application. This history is critical for determining the patent's effective filing date and expiration.

The priority chain is as follows:

• U.S. Patent 12,264,358 (Application No. 18/652,923), filed May 2, 2024.
• Which is a continuation of Application No. 17/708,050, filed March 30, 2022.
• Which is a continuation of U.S. Patent No. 11,299,767 (from App. No. 17/363,097, filed June 30, 2021).
• Which is a continuation of U.S. Patent No. 11,078,520 (from App. No. 16/157,243, filed October 11, 2018).
• Which is a continuation of U.S. Patent No. 10,138,509 (from App. No. 14/774,282, filed September 10, 2015).
• This application (14/774,282) is the U.S. National Stage entry of PCT Application No. PCT/US2014/018580, filed on February 26, 2014.
• The PCT application claims priority to U.S. Provisional Application No. 61/777,383, filed on March 12, 2013.

The critical date for calculating the patent term is the filing date of the international PCT application, as it is the earliest non-provisional application in the chain.

Patent Family

The patent family for US 12,264,358 originates from the international patent application PCT/US2014/018580. This has led to the grant of patents or the filing of applications in multiple jurisdictions. While a complete list is extensive, key family members identified through public databases include:

• United States: The extensive family includes the patents in the priority chain (11,299,767; 11,078,520; 10,138,509) and other related applications.
• European Patent Office (EPO): EP2912185
• Japan: JP6481137
• China: CN105101689
• Australia: AU2014229649
• Canada: CA2903743

This broad international filing indicates the assignee's intent to protect the technology in major global markets.

Projected Expiration Date

The term of a U.S. patent is 20 years from the filing date of the earliest U.S. or PCT application to which priority is claimed (excluding provisional applications).

• Earliest Non-Provisional Filing Date: February 26, 2014 (filing date of PCT/US2014/018580).
• Base Expiration Date: February 26, 2034 (20 years from the PCT filing date).

Assuming no Patent Term Adjustment is granted, the projected expiration date is February 26, 2034. This date could be extended if the USPTO later determines that administrative delays occurred during the prosecution of application 18/652,923.

Defensive Disclosure and Prior Art Declaration

Publication Date: April 26, 2026
Subject: Derivative Methods and Applications for Spatially Resolved In Situ Nucleic Acid Sequencing
Reference Technology: The core inventive concept disclosed in U.S. Patent 12,264,358, pertaining to the formation of an in situ 3D nucleic acid matrix for spatially resolved amplification and sequencing.
Purpose: This document is intended to enter the public domain as prior art. It discloses a plurality of variations, extensions, and applications of the reference technology to render subsequent, incremental, and obvious improvements non-patentable.

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Axis 1: Material & Component Substitution

Derivative 1.1: Thermo-Reversible Hydrogel Matrix for Sample Recovery

Enabling Description: A method for in situ nucleic acid sequencing where the matrix is composed of a thermo-reversible polymer, such as poly(N-isopropylacrylamide) (PNIPAM) or a Poloxamer (e.g., Pluronic® F-127), co-polymerized with acrydite-modified nucleic acid primers and linkers. The gelation process is initiated by raising the temperature of the permeabilized biological sample above the polymer's lower critical solution temperature (LCST), typically to 32-37°C. All subsequent steps, including reverse transcription, rolling circle amplification, and iterative sequencing, are performed at this elevated temperature to maintain the gel state. Following data acquisition, the sample temperature is lowered below the LCST (e.g., to 4°C), causing the hydrogel to dissolve into a liquid phase. This enables the non-destructive recovery of specific cells or tissue regions, identified by their spatial coordinates from the sequencing map, for subsequent multi-omic analyses like proteomics or metabolomics.

flowchart TD
    A[Permeabilize Biological Sample at 4°C] --> B{Infuse with liquid PNIPAM/Poloxamer precursor mix containing Acrydite-cDNA primers};
    B --> C[Raise Temperature to 37°C];
    C --> D[Thermo-reversible Hydrogel Matrix Forms In Situ];
    D --> E[Perform In Situ Amplification & Sequencing Cycles at 37°C];
    E --> F[Acquire 3D Spatial Sequence Data];
    F --> G[Lower Temperature to 4°C];
    G --> H[Matrix Dissolves, Releasing Cellular Content];
    F --> I{Identify Target Cells based on Sequence Map};
    I --> J[Micro-dissect/Recover Target Cells from Liquid Phase for Proteomics];

Derivative 1.2: Electrically Conductive Polymer Matrix for Electronic Detection

Enabling Description: This variation replaces the optically transparent hydrogel with an electrically conductive polymer matrix, enabling a label-free electronic readout of sequencing events. A biocompatible conductive polymer, such as a poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) hydrogel, is formed in situ. The native nucleic acids are immobilized within this matrix. The sequencing-by-synthesis process is monitored electronically instead of optically. The incorporation of each nucleotide by a polymerase causes a transient, localized change in the ionic environment and pH, which is detected as a minute fluctuation in impedance or potential by a grid of micro-electrodes integrated at the base of the sample. An array of amplifiers and analog-to-digital converters translates these signals into a base call for each specific spatial coordinate, obviating the need for fluorescent labels and complex optical imaging systems.

sequenceDiagram
    participant P as Polymerase
    participant M as Micro-electrode Array
    participant A as Amplifier & ADC
    participant C as Base Caller

    loop For each sequencing cycle
        P->>M: Incorporates nucleotide at coordinate (x,y,z)
        Note over M: Local impedance change (ΔZ) occurs
        M->>A: Transmits analog signal for (x,y,z)
        A->>C: Sends digitized ΔZ signal
        C->>C: Identifies base ('G') from signal signature
    end

Derivative 1.3: Quantum Dot (QD) Labels for Enhanced Multiplexing and Stability

Enabling Description: This method substitutes conventional organic fluorophores used in sequencing-by-synthesis with semiconductor quantum dots (QDs). Four populations of QDs, each with a distinct emission wavelength (e.g., 525 nm, 565 nm, 605 nm, 655 nm), are respectively conjugated to the four nucleotide triphosphates (A, C, G, T). Due to the QDs' high quantum yield and extreme photostability, the signal-to-noise ratio is significantly enhanced, and the number of sequencing cycles can be extended beyond 100 rounds without significant photobleaching. The narrow, symmetric emission peaks of QDs also allow for the potential of hyperspectral imaging to deconvolve signals from more than four labels simultaneously, enabling interrogation of multiple sequences or modifications at each location per cycle.

classDiagram
    class Nucleotide {
        +base: char
    }
    class QuantumDot {
        +emissionWavelength: int
        +coreMaterial: string
        +shellMaterial: string
    }
    class QD_Nucleotide {
        +conjugationLinker: string
    }

    Nucleotide <|-- QD_Nucleotide
    QuantumDot <|-- QD_Nucleotide
    QD_Nucleotide "1" -- "1" Nucleotide : conjugatedTo
    QD_Nucleotide "1" -- "1" QuantumDot : hasLabel

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Axis 2: Operational Parameter Expansion

Derivative 2.1: Cryo-Spatial Transcriptomics (Cryo-ST)

Enabling Description: A method to perform spatial sequencing on vitrified, non-fixed biological samples. The sample is flash-frozen in liquid ethane, preserving cellular ultrastructure with minimal ice crystal damage. A cryo-compatible matrix precursor (e.g., a low-concentration polyacrylamide solution with cryoprotectants like glycerol) is infused into the sample via cryo-focused ion beam (FIB) milling channels. Polymerization is initiated via UV light at cryogenic temperatures (e.g., -150°C). All subsequent enzymatic reactions (reverse transcription, amplification, ligation) are performed using cold-adapted enzymes (e.g., psychrophilic polymerases and ligases sourced from arctic microorganisms) in cryo-compatible buffers. Imaging is performed on a cryo-confocal microscope. This process provides a near-native-state spatial map of gene expression, completely avoiding chemical fixation artifacts.

stateDiagram-v2
    [*] --> Vitrification
    Vitrification --> FIB_Milling: Sample Flash-Frozen
    FIB_Milling --> Infusion: Create channels
    Infusion --> Cryo_Polymerization: Infuse matrix precursors at -150°C
    Cryo_Polymerization --> Cryo_Enzymatics: UV-initiated gelation
    Cryo_Enzymatics --> Cryo_Imaging: Use cold-adapted enzymes
    Cryo_Imaging --> Data_Analysis: Acquire sequence data
    Data_Analysis --> [*]

Derivative 2.2: Macroscopic Whole-Organ Spatial Sequencing

Enabling Description: Scaling the in situ sequencing methodology to intact macroscopic samples, such as an entire mouse brain or plant seedling. The organ is first decellularized and permeabilized via vascular perfusion with a detergent solution, followed by perfusion with the hydrogel precursor mix. After gelation, the resulting organ-hydrogel hybrid is optically cleared using techniques like CLARITY. The sequencing reagents are then cyclically flowed through the remnant vascular system of the organ. Data acquisition is performed using a light-sheet fluorescence microscope (LSFM), which allows for rapid optical sectioning and imaging of the entire cubic-centimeter-scale sample. The resulting dataset is a complete, 3D molecular atlas of the organ at cellular resolution.

flowchart LR
    A[Mouse Brain] --> B(Vascular Perfusion with Detergent);
    B --> C(Perfusion with Hydrogel Precursors);
    C --> D{Gelation & Optical Clearing (CLARITY)};
    D --> E(Mount in Light-Sheet Microscope);
    E --> F(Cyclic Reagent Flow via Cannulated Arteries);
    F --> E;
    E --> G[High-speed 3D Imaging of Sequencing];
    G --> H[Reconstruction of Whole-Brain Transcriptome];

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Axis 3: Cross-Domain Application

Derivative 3.1 (Aerospace): In-Situ Mapping of Material Fatigue via Engineered Biosensors

Enabling Description: Composite materials used in aerospace structures are embedded with engineered, dormant bacterial spores (Bacillus subtilis). The spores contain a DNA plasmid with a "reporter cassette" flanked by sequences recognized by a stress-activated recombinase. Upon experiencing specific mechanical stress thresholds (e.g., >200 MPa), the spores germinate and the recombinase is expressed, which inverts or excises the DNA reporter cassette. For maintenance checks, a handheld device drills a micro-core from the material, perfuses it in situ with the hydrogel matrix and sequencing reagents. The spatial sequencing map reveals the 3D locations of bacteria with altered DNA, providing a high-resolution, cumulative record of material fatigue and micro-fracture propagation.

graph TD
    subgraph Aircraft Wing Composite
        A(Spores with Intact DNA)
        B(Spores with Flipped DNA)
    end
    subgraph Maintenance Check
        C[Micro-core Extraction]
        D[In-situ Gelation & Sequencing]
        E{3D Fatigue Map}
    end
    A -- Mechanical Stress --> B
    A & B -- Core Sample --> C
    C --> D
    D --> E

Derivative 3.2 (AgTech): Spatially Resolved Soil Metatranscriptomics

Enabling Description: A hollow, porous probe is inserted directly into an agricultural soil bed. A solution of hydrogel precursors is injected through the probe, permeating a small volume of soil and encapsulating the native soil microbiome in situ. The probe then delivers a sequence of reagents to: (1) lyse the microorganisms, (2) immobilize the released RNA into the gel matrix, (3) perform reverse transcription, amplification, and sequencing. The probe contains an integrated fiber optic imaging bundle connected to a portable sequencer. The resulting data provides a 3D map of gene expression across different microbial species in their undisturbed microenvironment, revealing metabolic activity and symbiotic/competitive interactions around plant roots.

sequenceDiagram
    participant Probe
    participant Soil_Microbiome
    participant Sequencer

    Probe->>Soil_Microbiome: Injects hydrogel precursors
    Note right of Probe: Matrix forms, encapsulating microbiome
    Probe->>Soil_Microbiome: Injects lysis & RT reagents
    Probe->>Soil_Microbiome: Injects amplification & sequencing reagents
    loop Sequencing Cycles
        Probe->>Sequencer: Transmits optical data via fiber bundle
    end
    Sequencer-->>Probe: Generates 3D metatranscriptomic map

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Axis 4: Integration with Emerging Tech

Derivative 4.1 (AI-driven Optimization): Adaptive, Interest-Driven Sequencing

Enabling Description: The in situ sequencing process is controlled by a convolutional neural network (CNN) in a closed loop. After an initial, low-resolution sequencing pass (e.g., 2-3 cycles) across the entire sample, the CNN analyzes the nascent spatial gene expression patterns. It identifies "regions of interest" (ROIs) based on pre-trained models for features like tumor heterogeneity, immune cell infiltration, or neural activity boundaries. The system's controller then automatically modifies the data acquisition plan: it increases the imaging magnification, decreases the pixel binning, and allocates more sequencing cycles specifically to the ROIs, while continuing sparse sampling elsewhere. This AI-driven approach maximizes the information density acquired from biologically significant regions while minimizing instrument time and data storage costs.

flowchart TD
    A[Start] --> B(Perform Low-Res Global Sequencing: Cycles 1-3);
    B --> C{Send 3D Map to CNN for Analysis};
    C --> D{CNN Identifies Regions of Interest (ROIs)};
    D --> E(Update Instrument Protocol);
    subgraph High-Res Targeted Sequencing
        F[Increase Magnification on ROIs]
        G[Increase Cycle Count on ROIs]
    end
    E --> F & G
    G --> H(Acquire Deep Data from ROIs);
    H --> C;

Derivative 4.3 (Blockchain Verification): Immutable Provenance for Clinical Diagnostics

Enabling Description: For clinical applications, each step of the spatial sequencing workflow is tied to a private blockchain to ensure an immutable audit trail. When a patient biopsy is received, its metadata (patient ID, time, location) is used to generate a cryptographic hash, creating the genesis block. Subsequent steps, such as matrix formation, reagent lot number application, instrument ID for the sequencing run, and the raw image data hash, are added as sequential transactions to the chain. The final diagnostic report, containing the spatial gene expression map, is also hashed and linked. Any user, from pathologist to patient, can cryptographically verify the entire provenance of the result, ensuring the data has not been tampered with and is linked to the correct original sample.

erDiagram
    PATIENT ||--o{ BIOPSY : has
    BIOPSY ||--|{ BLOCKCHAIN_RECORD : "is recorded in" {
        string tx_hash PK
        string block_id
        timestamp ts
    }
    BLOCKCHAIN_RECORD ||--|{ HASHED_DATA : "contains" {
        string data_type
        string data_hash
    }
    INSTRUMENT ||--|{ BLOCKCHAIN_RECORD : "generates"
    DIAGNOSTIC_REPORT ||--|{ BLOCKCHAIN_RECORD : "finalizes"

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Axis 5: The "Inverse" or Failure Mode

Derivative 5.1: Enzymatically Dissolvable Matrix for "Read-then-Recover" Workflow

Enabling Description: The hydrogel matrix is formulated with cross-linkers containing a substrate for a specific, non-endogenous enzyme. For example, the bis-acrylamide cross-linker is replaced with a peptide linker containing a Tobacco Etch Virus (TEV) protease cleavage site. The entire spatial sequencing protocol is executed to generate the 3D gene expression map. Based on this map, specific cell populations are identified for further study (e.g., a rare cancer stem cell clone). A solution containing TEV protease is then introduced, which selectively digests the peptide cross-linkers and dissolves the hydrogel. The targeted cells are then recovered from the liquified sample using micromanipulation or FACS, enabling a direct link from spatial transcriptome to single-cell proteomics or functional assays.

graph TD
    A[In-Situ Sequencing in TEV-Cleavable Matrix] --> B(Generate 3D Transcriptome Map);
    B --> C{Identify Rare Cell at Coords (x,y,z)};
    C --> D(Perfuse Sample with TEV Protease);
    D --> E[Matrix Dissolves];
    E --> F(Recover Cell from (x,y,z) via Micropipette);
    F --> G[Perform Downstream Single-Cell Proteomics];

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Combination Prior Art Scenarios

1. Combination with OpenFlexure Microscope and Micro-Manager: The sequencing imaging system is built using the OpenFlexure Microscope, an open-source, 3D-printed microscopy platform. Instrument control for the multi-day, cyclic sequencing process is automated using Micro-Manager, an open-source software package for microscope control. Custom scripts written in Python or Beanshell within Micro-Manager handle the fluidics control, autofocus, and multi-channel image acquisition sequences.
2. Combination with FAIR Data Principles and Common Workflow Language (CWL): The entire data analysis pipeline, from raw image stacks to a spatially resolved gene expression matrix, is containerized (e.g., using Docker) and described using the Common Workflow Language (CWL), an open standard for portable, reproducible data analysis workflows. The final data and metadata are published according to FAIR (Findable, Accessible, Interoperable, Reusable) data principles, ensuring the results can be easily discovered and integrated with other public spatial omics datasets.
3. Combination with ONNX AI Model Format: The AI model used for adaptive sequencing (Derivative 4.1) is trained using a standard framework (e.g., PyTorch) and then exported to the Open Neural Network Exchange (ONNX) format. This open-source format allows the inferencing model to be deployed on diverse hardware platforms (e.g., NVIDIA Jetson, FPGA) embedded in the microscope controller, ensuring interoperability and decoupling the model's execution from the original training environment.