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Plasmid Extraction
Plasmid quality directly affects downstream experiments such as restriction digestion, sequencing, cloning, cell transfection, animal injection, gene therapy, and vaccine development.
We provide high-purity plasmid extraction from μg and mg to gram scale, with optional endotoxin removal. Optimized alkaline lysis and purification processes help maintain plasmid integrity and a high supercoiled-DNA ratio.
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  • 1-2business days

    Fastest Mini turnaround time

  • 10μg-50mg

    Standard production scale

  • ≥ 90%

    Transfection-grade supercoiled DNA

  • < 0.005 EU/μg

    Optional ultra-low endotoxin

首页 > Products > Gene Synthesis > Plasmid Extraction >
Introduction
Service Advantages
Service Details
Optional Add-On Services
Service Workflow
Delivery Standards
Quality Control Standards
Technical Guide
Applications
FAQ

Plasmid Extraction

High-Purity Plasmids from Microgram to Gram Scale for Downstream Applications

Plasmid quality directly affects downstream experiments including restriction digestion, sequencing, cloning, cell transfection, animal injection, gene therapy, and vaccine development.

Zhiyin Biotechnology provides high-purity plasmid extraction services from μg and mg to g scale, with optional endotoxin removal. Optimized alkaline lysis and purification processes help preserve plasmid integrity and a high supercoiled proportion for applications ranging from routine molecular experiments to sensitive cell transfection and in vivo animal studies.

  • Production scales from μg and mg to g
  • Research-grade, transfection-grade, and ultra-low-endotoxin options
  • Transfection-grade plasmids with ≥90% supercoiled form
  • Complete quality-control report included

Service Advantages

Flexible Scale, Rigorous QC, Rapid Delivery, and Selectable Endotoxin Standards
  • Flexible Production Scale
    From Mini 10 μg to Giga 50 mg, supporting both high-copy and low-copy plasmids; larger scales can be customized by project.
  • Rigorous Quality Control
    Routine testing includes concentration, A260/A280, gel electrophoresis, and supercoiled proportion. Transfection-grade material also undergoes LAL endotoxin, residual RNA, and genomic DNA testing.
  • Rapid Delivery
    Mini preparations can be completed in as little as 1–2 business days. Large-scale and endotoxin-free plasmid preparations typically take 3–5 business days, with expedited service available.
  • Endotoxin Removal
    Transfection-grade standard: <0.05 EU/μg; optional ultra-low <0.01 EU/μg or extremely low <0.005 EU/μg for sensitive cells and animal experiments.
  • High Supercoiled Proportion
    Optimized processes protect plasmid integrity; research-grade material has a supercoiled proportion ≥80%, and transfection-grade material ≥90%.
  • One-Stop Service
    Can be integrated with gene synthesis, cDNA/ORF cloning, and shRNA/gRNA construction for one-stop delivery from sequence to high-quality plasmid.

Service Details

Select the Purity Grade and Endotoxin Standard Based on the Downstream Application
Service Grade Endotoxin Standard Preparation Scale Turnaround Time Price
Research Grade
 Not applicable (no endotoxin removal) μg to mg scale From 3 business days
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Transfection Grade
 <0.05 EU/μg μg to mg scale From 3–5 business days
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Transfection Grade (Ultra-Low Endotoxin)
 <0.01 EU/μg μg to mg scale From 4–6 business days
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Transfection Grade (Extremely Low Endotoxin)
 <0.005 EU/μg μg to mg scale From 5–7 business days
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Service Notes:Supports plasmid preparation from μg to mg scale; larger scales can be customized by project. Multiple endotoxin-control standards are available for transfection-grade preparations.

Optional Add-On Services

Add validation services according to project requirements
Service Description Additional Time
Endotoxin Removal Upgrade Upgrade from research grade to transfection grade or to a stricter standard 1–2 business days
Whole-Plasmid Sequencing Verification Complete whole-plasmid sequence verification by Sanger sequencing 3–5 business days
Restriction Digestion Analysis Verify plasmid integrity and the insert 1 business day
Supercoiled Proportion Measurement Gel electrophoresis densitometry 1 business day
Residual RNA/DNA Testing Detect residual host RNA and genomic DNA 1–2 business days

Recommendation:For sensitive cells, animal studies, or viral packaging, upgrade endotoxin and integrity-verification standards as needed.

Service Workflow

Requirement confirmation, standardized production, comprehensive QC, and on-time delivery
  • Submit Requirements
    Provide the vector name/sequence, resistance marker, purity grade, preparation scale, endotoxin standard, and additional QC requirements.
  • Plan and Quotation
    Complete feasibility assessment, plan confirmation, and quotation within 1 business day.
  • Standardized Production
    Strain recovery, culture, alkaline lysis, purification/endotoxin removal, concentration, and quality testing under SOP-controlled processes.
  • Delivery and Support
    Deliver liquid or lyophilized plasmid, optional glycerol stock, a complete QC report, and technical support.

Delivery Standards

Traceable delivery of samples, strains, sequences, and quality documents
  • High-Purity Plasmid
    Delivered in TE/ddH2O solution or lyophilized form at the agreed concentration and total amount.
  • Optional Glycerol Stock
    DH5α or a specified host, stored at −80°C.
  • Quality Report (COA)
    Includes concentration, A260/A280, A260/A230, total amount, and supercoiled proportion.
  • Sequence Files
    FASTA or GenBank format files are provided.
  • Optional Verification Files
    Restriction maps, whole-plasmid sequencing results, and production records are provided as requested.

Quality Control Standards

Multi-level quality control for every plasmid preparation batch under the ISO 9001 quality management system
Test Item Research Grade Transfection Grade Test Method
Concentration Tested Tested A260
A260/A280 1.8-2.0 1.8-2.0 UV spectrophotometry
Supercoiled Proportion ≥80% ≥90% Gel densitometry
Endotoxin — <0.05 EU/μg (upgrade available) LAL assay
Residual RNA — Not detected Gel/specialized assay
Residual Genomic DNA — Not detected Specialized assay
Restriction Digestion Optional Optional Restriction digest electrophoresis
Whole-Plasmid Sequencing Optional Optional Sanger sequencing

Transfection-grade plasmids additionally undergo endotoxin, residual RNA, and host genomic DNA testing, with the corresponding QC report.

How to Choose an Endotoxin Level

Endotoxin affects transfection efficiency, immune responses, and gene expression; select an appropriate level based on cell sensitivity and in vivo use
Application Type Recommended Endotoxin Level Selection Guide
Routine Molecular Biology Experiments Usually no specific control required Basic experiments such as digestion, cloning, and sequencing
Routine Cell Transfection <0.1 EU/μg Common cell-line transfection and protein expression
Sensitive Cells or Animal Studies <0.01 EU/μg Primary cells, stem cells, immune cells, and in vivo studies
Highly Sensitive Applications <0.005 EU/μg Projects with stringent requirements for inflammatory background and batch consistency

Technical Note:Endotoxin is lipopolysaccharide (LPS) from the cell wall of Gram-negative bacteria. It can reduce transfection efficiency, activate inflammatory responses through the TLR4 pathway, induce cytokines such as IL-1, IL-6, and TNF-α, interfere with target-gene expression, and increase nonspecific inflammation risk in animal studies.

Applications

Match purity, supercoiled proportion, and endotoxin grade to the downstream application
Basic Molecular Biology

Basic Molecular Biology

Restriction digestion, ligation, subcloning, PCR, sequencing, probe preparation, and library screening.

Cell Transfection and Protein Expression

Cell Transfection and Protein Expression

For transient or stable transfection and protein expression in HEK293, HeLa, CHO, and similar cells; transfection grade with ≥90% supercoiled form is recommended.

Sensitive-Cell Transfection

Sensitive-Cell Transfection

For primary cells, stem cells, DCs, T cells, and macrophages; endotoxin <0.01 EU/μg is recommended.

Animal Experiments and In Vivo Studies

Animal Experiments and In Vivo Studies

For mouse/rat injection, intratumoral injection, and DNA immunization; ultra-low endotoxin and sterile processing as needed are recommended.

In Vitro Transcription and RNA Synthesis

In Vitro Transcription and RNA Synthesis

For mRNA/sgRNA in vitro transcription and RNA probe preparation; high-purity, highly supercoiled plasmid supports linearization and stable transcription.

Gene Therapy and Vaccine Development

Gene Therapy and Vaccine Development

For lentiviral/AAV packaging, DNA vaccines, and large-scale process development; ≥90% supercoiled form and ultra-low endotoxin are recommended.

FAQ

Common questions and selection guidance for plasmid extraction
How should I choose between research-grade and transfection-grade plasmids?
The main differences are endotoxin level and supercoiled proportion. Research grade is suitable for routine digestion, sequencing, and cloning; transfection grade is recommended for cell transfection, animal injection, viral packaging, and in vitro transcription, with stricter endotoxin standards based on cell sensitivity.
What is endotoxin and why must it be removed?

Endotoxin (LPS) is a lipopolysaccharide component of the E. coli outer membrane. Bacterial lysis releases endotoxin during plasmid preparation, and without removal it can co-purify with the plasmid.


Endotoxin has three major negative effects on transfection:
(1) It competes with plasmid DNA for cell-membrane binding, reducing transfection efficiency;
(2) It activates immune cells through TLR4, inducing inflammatory cytokines and altering cell condition;
(3) It interferes with gene-expression regulation, reducing experimental reliability.


Therefore, endotoxin-free plasmids are required for cell transfection—especially primary, stem, and immune cells—and for animal studies.

How should I choose among Mini, Midi, Maxi, Mega, and Giga?
Mini (10–30 μg) suits digestion/sequencing/PCR verification; Midi (100–200 μg) suits 6-well plate/10 cm dish transfection; Maxi (500 μg–1 mg) suits T75/15 cm dish transfection or small-animal injection; Mega (2–5 mg) suits large-animal studies or repeated transfections; Giga (10–50 mg) suits large-scale experiments.
Typical estimates: one 6-well plate transfection requires about 2–5 μg plasmid, T75 about 10–20 μg, and a 100 mm dish about 5–10 μg. Select the scale based on experiment count, dose per experiment, and reserve amount.
What is the difference between large-scale and small-scale preparation?
The main differences are culture volume, purification scale, total yield, and the number of downstream experiments supported. Large-scale preparation is more suitable for repeated transfection, animal studies, or viral packaging.
Why is the supercoiled proportion important?
The supercoiled conformation is more compact and stable and usually provides higher transfection efficiency and expression. A supercoiled proportion ≥90% is recommended for transfection-grade plasmids.
Can low-copy plasmids be prepared?
Yes. Because low-copy plasmids have fewer copies per cell, yields at the same culture volume are typically only 1/5 to 1/10 of high-copy plasmids. Strain, culture, and purification conditions must be optimized; selecting the next larger preparation scale is recommended, with an additional 1–2 business days.
How should plasmids be stored?
Liquid plasmid can be stored at 4°C for 1–2 weeks; for long-term storage, −20°C or −80°C is recommended and typically supports more than 1 year. Lyophilized plasmid can be stored at −20°C or 4°C for 2–3 years; glycerol stocks should be stored at −80°C and typically remain usable for more than 5 years.

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