A Technical Guide to Norgen Biotek’s RNA Purification Portfolio
From core silicon carbide (SiC) technology to multi-omics and high-throughput applications
In This Guide, You’ll Learn:
- The advantages of Norgen’s silicon carbide (SiC) resin for unbiased, true total RNA purification.
- How specialised kits deal with difficult samples such as liquid biopsies, FFPE tissue and stool.
- A step-by-step framework for choosing the right kit for your sample, analyte and downstream application.
Estimated read time: 8 minutes
Core Technology: The Power of Silicon Carbide
The quality, yield and biological fidelity of a purified RNA sample depend on the extraction chemistry behind it. Norgen Biotek’s platform is built around a proprietary resin separation matrix made from silicon carbide (SiC), which underpins the company’s entire RNA purification portfolio.
Traditional silica-based matrices can show a binding bias towards high molecular weight and high guanine-cytosine (GC) content nucleic acids. SiC instead shows a uniform binding affinity for all RNA species, regardless of size or GC content.
This unbiased binding is what allows “true total RNA” purification, covering everything from large ribosomal RNAs (rRNA) and messenger RNAs (mRNA) down to the small RNA fraction (<200 nucleotides), which includes microRNAs (miRNAs). It is particularly useful for miRNA profiling and for compromised samples, such as degraded RNA from FFPE tissue.
Efficient recovery of small RNAs (e.g. miRNAs)
Purity, Sensitivity and Safety
Three interconnected strengths come from the properties of the SiC resin.
1. Broad Spectrum, Unbiased RNA Binding
Size-agnostic binding recovers the full transcriptome, including small non-coding RNAs. This matters for microRNA profiling and for getting the most from fragmented samples such as FFPE tissue.
2. High Sensitivity without Carrier RNA
High binding affinity allows high-quality RNA to be isolated from very low-input samples, down to a single cell or as few as 10 viral copies, without carrier RNA. This is important because carrier RNA can interfere with sensitive applications such as Next-Generation Sequencing (NGS) by consuming sequencing reads.
3. Phenol/Chloroform-Free Extraction
Norgen’s protocols avoid hazardous organic solvents, which improves laboratory safety and simplifies disposal. It also removes the risk of solvent carryover inhibiting enzymatic reactions such as reverse transcription and PCR, and suits automation.
Total RNA Kits: The Everyday Workhorse
The Total RNA Purification series is the foundation of the range. It is designed for isolating total RNA (including miRNA) from common sample types such as cultured cells, animal tissues, blood, bacteria, yeast and viruses.
Core Variants for Contamination Control and Input Size
Total RNA Purification Plus Kit
This version tackles genomic DNA (gDNA) contamination. A separate gDNA Removal Column takes gDNA out of the lysate before RNA purification, which is a more robust option than enzymatic DNase digestion. It is the preferred choice for gDNA-sensitive work such as RT-qPCR.
Micro and Single Cell Kits
For precious, minute samples (e.g. microdissected tissue or fewer than 500,000 cells), the Micro Kits use a specialised column that allows elution in as little as 20 µL. The Single Cell RNA Purification Kit isolates total RNA from as little as a single cell, with an elution volume of just 8 µL.
Formats for Throughput and Automation
| Format | Primary Use | Advantage |
|---|---|---|
| Spin Column | Standard, low to moderate sample numbers | Simple, reliable, manual single-prep format. |
| 96-Well Kits | High-throughput screening | Processes many samples at once with vacuum manifolds or plate centrifuges. |
| Magnetic Bead System | Automation on robotic liquid handlers | Magnetic separation is simpler to automate than the centrifugation or vacuum steps needed for columns. |
This modularity means you can validate a protocol with a standard spin-column kit, then move to high-throughput (96-well) or gDNA-sensitive (“Plus”) formats without extensive re-validation.
Kits for Challenging Samples
Norgen’s specialised kits use dedicated buffers and tailored protocols to deal with the specific biochemical problems of difficult starting materials, giving you a complete sample preparation workflow.
Liquid Biopsies (Plasma, Serum, Urine)
Cell-free RNA (cf-RNA) is present at very low concentrations. Kits such as the Plasma/Serum cfc-RNA Advanced Purification Kit can process and concentrate up to 6 mL of plasma or serum into a small elution volume. The Leukocyte RNA Purification Kits use an RBC Lysis Buffer to selectively remove globin mRNA, improving sensitivity for gene expression studies from whole blood. Dedicated kits are also available for blood collected in clinical preservation tubes such as PAXgene and Tempus.
Tissues and Archived Samples
The Fatty Tissue RNA Purification Kit uses chemistry designed for high-lipid samples. The FFPE RNA Purification Kits address formalin-fixed, paraffin-embedded tissue with a heating step that partially reverses formalin cross-links, and SiC’s ability to bind the resulting small RNA fragments.
Microbiome and Environmental Samples (Stool, Soil)
Stool and soil are complex samples, with potent PCR inhibitors such as humic acids. The Stool Total RNA Purification Kit and Soil Total RNA Purification Kit include bead tubes for mechanical homogenisation of microorganisms, plus dedicated chemistry (including Humic Acid Removal (HAR) columns for soil) to remove these inhibitors. The result is RNA suited to sensitive metagenomics and RT-qPCR.
Advanced Workflows: Multi-Omics and NGS-Ready RNA
For systems biology and ultra-sensitive analysis, Norgen offers multivariate kits and a high-purity range.
Multi-Omics: Sequential Isolation from a Single Sample
Norgen’s Multivariate Kits sequentially isolate two or three classes of macromolecule (RNA, DNA and/or protein) from a single, undivided sample. For multi-omics analysis, this removes the experimental variation and analytical uncertainty that come from splitting a precious sample.
- RNA/DNA Purification Kit: a sequential two-column workflow that binds and separates gDNA and total RNA (including miRNA).
- RNA/Protein Purification Plus Kit: a single-column procedure in which RNA is eluted first, then protein in a buffer compatible with mass spectrometry and Western blotting, avoiding precipitation steps.
- RNA/DNA/Protein Purification Plus Kit: the most comprehensive option, isolating gDNA, RNA and protein in sequence with a two-column system.
EXTRAClean Portfolio: Purity for NGS
The EXTRAClean kits are engineered for the highest purity, aimed at low-input samples and sensitive downstream applications such as NGS, where trace background contamination can obscure results.
Their defining feature is an enhanced manufacturing and quality control process, in which columns and reagents are processed to minimise trace contaminants.
Key Benefits:
- Next-Generation Sequencing (NGS): reduces background noise and improves microRNA mapping.
- Low-input RNA samples: supports reliable results from precious, limited material.
Find Your Kit: A Selection Guide
Choosing the right kit comes down to four things: your starting material, the target analyte, the scale of the work and how sensitive your downstream application is.
Norgen RNA Purification Kit Selection Matrix
| Kit Category | Primary Sample Type(s) | Target Analyte(s) | Key Features | Available Formats | Recommended Downstream Applications |
|---|---|---|---|---|---|
| Total RNA Purification / Plus | Cells, tissues, blood, bacteria, yeast, viruses, fluids | Total RNA (incl. miRNA) | SiC resin, phenol-free, Plus has gDNA Removal Column | Spin column, 96-well, magnetic bead, Micro, Maxi, Single Cell | RT-qPCR, microarrays, NGS, Northern blotting, digital PCR |
| Cell-Free RNA (cf-RNA) Purification | Plasma, serum, urine | Circulating RNA (incl. exosomal RNA, miRNA) | Large volume input, RNA concentration, SiC resin | Mini, Midi, Maxi (spin column) | Liquid biopsy, biomarker discovery, RT-qPCR, small RNA-Seq |
| Leukocyte RNA Purification | Whole blood | Leukocyte total RNA (incl. miRNA) | RBC lysis, globin mRNA reduction, SiC resin | Spin column, 96-well | Gene expression profiling, immunology, RT-qPCR |
| FFPE RNA Purification | Formalin-fixed paraffin-embedded tissue | Total RNA (incl. miRNA) | Formalin cross-link reversal, degraded RNA recovery | Spin column, 96-well | Archival studies, pathology, cancer research, RT-qPCR, NGS |
| Stool / Soil Total RNA Purification | Stool, soil, compost, manure | Host and microbial total RNA (incl. miRNA) | Inhibitor removal (humic acids), bead homogenisation | Spin column | Microbiome and metatranscriptomics analysis, RT-qPCR, environmental genomics |
| Exosome and Exosomal RNA Purification | Plasma, serum, urine, cell culture media | Intact exosomes and exosomal RNA | Rapid exosome capture, no ultracentrifugation, EXTRAClean option | Mini, Midi, Maxi (spin column) | Biomarker discovery, functional studies, small RNA-Seq |
| RNA/DNA / RNA/Protein / RNA/DNA/Protein Purification | Cells, tissues, blood, yeast, bacteria, FFPE (for RNA/DNA) | Sequential RNA/gDNA, RNA/protein, or all three | Conserves sample, single column for RNA/protein, mass spec-compatible protein buffer | Spin column, Micro, 96-well | Integrated genomics, transcriptomics and proteomics, multi-omics analysis |
A Three-Step Route to the Right Kit
- Identify your sample and goal: What are you starting with (e.g. tissue, blood, stool), and what do you need to isolate (RNA, DNA, protein, or all three)? This points you to the right kit category.
- Determine your scale: Do you have a tiny, precious sample or hundreds to process? Choose a Micro or Single Cell kit for low inputs, or a 96-well or magnetic bead format for high throughput.
- Match your application’s needs: Is your experiment sensitive to DNA contamination? Choose a “Plus” kit. Do you need the highest purity for NGS? Choose an EXTRAClean kit.
Recommendations for Common Scenarios
Scenario: Analysing cellular heterogeneity in organoid models
Recommendation: Single Cell RNA Purification Kit
Organoids need to be dissociated into individual cells to study differences in gene expression. The kit’s sensitivity helps you recover as much data as possible from each cell, so distinct cell populations and developmental pathways within the organoid can be resolved.
Scenario: Metatranscriptomic analysis of the gut microbiome
Recommendation: Stool Total RNA Purification Kit
The kit lyses tough microbial cells and removes the potent PCR inhibitors found in stool, which gives you more accurate gene expression data from a complex sample.
Scenario: Studying gene regulation in a university lab
Recommendation: RNA/DNA/Protein Purification Plus Kit
This gives a complete molecular snapshot from one sample set, which suits academic labs studying the central dogma. It also removes the variability of processing separate samples for genomic, transcriptomic and proteomic analysis.
Ready to Optimise Your RNA Purification Workflow?
Norgen’s SiC technology gives unbiased binding for true total RNA recovery, from large mRNAs to microRNAs, including from challenging and low-input samples.