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We offer a range of ultra pure, high-quality reagents for a variety of molecular biology applications such as nucleic acid electrophoresis, nucleic acid purification and sequencing, PCR and more.

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Nucleic Acid Electrophoresis

Fisher BioReagents offers a wide range of reagents for Nucleic Acid Electrophoresis applications. Choosing the right reagents will allow you to achieve optimal results in your experiment. Use our quick selection guides to assist you in finding the right grades of Agarose, Buffer and Ladders.

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Agarose is a linear polysaccharide composed of alternating residues of D- and L-galactose that are joined by glycosidic linkages. Agarose forms gels that are both porous and resilient. These gel properties provide a sieving matrix, which allows the electrophoretic separation of charged macromolecules, such as DNA or RNA, according to size. Compared to polyacrylamide gel, agarose has a lower resolution but wider range of separation. Lower grades of agarose can be contaminated with other polysaccharides, salts and proteins. Such impurities can alter the gelling/melting temperature of agarose solutions or affect the ability to use the recovered nucleic acid sample in a post-electrophoresis application.

Fisher BioReagents offers three different grades of agarose that are functionally tested and pre-qualified for specific applications. Agarose grades used in electrophoresis of nucleic acids:

  • Genetic Analysis Grade - Agarose that yields biologically active DNA or RNA. Testing includes enzymatic performance measurements
  • Molecular Biology Grade - Suitable for analytical separation of DNA or RNA
  • PCR Grade - The original agarose for analytical separation of PCR amplicons (<1kb)

 Factors to Consider When Selecting an Agarose:

1. Size of DNA or RNA fragments to be analyzed:

Agarose Agarose Separation Ranges
Low EEO/Multipurpose 500bp to 23kb
Low Melting/Nucleic Acid Recovery 200bp to 25kb
Broad Separation Range for DNA/RNA 500bp to 25kb
Low Melting <1kb DNA/RNA 50bp to 1kb
Intermediate Melting 15bp to 1.2kb

2. Type of downstream application that will follow electrophoretic separation (eg. cloning procedures directly from re-melted agarose or in-gel reaction).

Aragose Selection Guide

Type of Agarose Low EEO Low Melting > 200bp Low Melting > 1000bp Wide Separation Range PCR Grade
Recovery of DNA and RNA x x x x x
Southern and Northern Biots x        
DNA/RNA Separation 50bp to 1kb     x   x
DNA/RNA Separation > 1kb x x   x  
PCR Fragment Analysis x x x x x
In-gel Reactions (ligation, transformations, PCR)     x    
Colony Lifts x        
Available Pack Sizes 100g to 500g 25g 100g 100g to 500g 100g
Agarose Grade Molecular Biology Molecular Biology Genetic Analysis Genetic Analysis PCR



Two buffers commonly used for DNA agarose electrophoresis are Tris-acetate with EDTA (TAE; 40mM Tris-acetate, 1mM EDTA) and Tris-borate with EDTA (TBE, 89mM Tris-borate, 2mM EDTA). Because the pH of these buffers is neutral, the phosphate backbone of DNA has a net negative charge and migrates toward the anode. TAE and TBE have different properties, which makes one more suitable than the other for a specific purpose.

The denaturing system chosen depends on the purpose of the RNA experiment and the size of the RNA fragment being separated. Formaldehyde denaturation is suitable if RNA samples are to be recovered. Formamide denaturation is suitable if the RNA needs to retain its biological activity.


Buffer Suggested Uses Properties
TAE DNA recovery; Electrophoresis of large DNA (>12 kb) Low buffering capacity; recirculation may be necessary for extended run times (>6 hr)
TBE Electrophoresis of small DNA (<1 kb); Increased resolution of small DNA (< 1kb) Decreased DNA mobility; High buffering capacity - no recirculation required for extended run times
MOPS Electrophoresis of formaldehyde denatured RNA Buffer is low in ionic strength; recirculation of buffer may be necessary


Suggested Agarose Concentrations

The optimal gel concentration depends on the size of the DNA fragments to be resolved.

Product Description Main Application DNA Size Range in Base Pairs Final Agarose Concentation % (W/V) 1x TAE Buffer Final Agarose Concentration % (W/V) 1x TBE Buffer
Low Melting, <1kb
Genetic Analysis
Certified recovery of small
nucleic acid fragments,
Outstanding resolution.
500-1,000 2.5 2.0
150-700 3.0 2.5
100-450 3.5 3.0
70-300 4.0 3.5
10-100 4.5 4.0
8-500 5.0 4.5
Low Melting, Nucleic<1kb
Acid Recovery,
Molecular Biology
Broad separation range,
Ideal for DNA and RNA
recovery after
electrophoretic separation.
500-25,000 0.75 0.70
300-20,000 1.0 0.85
200-12,000 1.25 1.00
150-6,000 1.50 1.25
100-3,000 1.75 1.50
50-2,000 2.0 1.75
Broad Separation
Range for DNA/RNA,
Genetic Analysis
Suitable for routine nucleic
acid electrophoresis
applications with broad
separation range.
1,000-23,000 0.60 0.50
800-10,000 0.80 0.70
400-8,000 1.00 0.85
300-7,000 1.20 1.00
200-4,000 1.50 1.25
100-3,000 2.00 1.75
Molecular Biology
Routine electrophoresis of
DNA and RNA. High gel
strength ideal for Southern
and Northern blotting.
1,000-23,000 0.60 0.50
800-10,000 0.80 0.70
400-8,000 1.00 0.85
300-7,000 1.20 1.00
200-4,000 1.50 1.25
100-3,000 2.00 1.75



To achieve the most accurate qualitative and quantitative analysis via agarose gel electrophoresis, the appropriate DNA or RNA standard is required. Fisher BioReagents provides a wide range of standards, including routine DNA ladders for quick size and quality assessment as well as Fisher Bioreagents™ exACTGene™ DNA ladders that allow for quantitative analysis.


Fisher Bioreagents™ RiboLadders™ RNA Standards

These standards can be used to assess single-stranded RNA molecules on both native and denaturing agarose gels. These unique RNA standards are lyophilized to reduce thawing-related degradation, to prolong shelf life and to ensure consistent performance.

Application Size Range Number of Bands Number of Loadings
Small RNA fragments 0.1-1kb 8 50
Large RNA fragments 0.2-4kb 9 50

Routine DNA Ladders/RiboLadders™ RNA Standards


exACTGene and Routine DNA Ladders

Ready-to-use (pre-mixed with the loading dye), room temperature, stable DNA ladders are available for all common electrophoresis applications.

Application Size Range Numbers of Bands Number of Loadings
exACTGene DNA ladders are ideal for qualitative analysis, quantitative estimation, and size assessment
PCR fragment analysis 25-650bp 14 100-10uL
PCR fragment analysis, small DNA digests 25-1,000bp 12 100/10uL
Quick check of PCR or enzyme digestion results 50-2,000bp 8 100/10uL
General purpose, small DNA fragments 100-1,000bp 10 100/10uL
Fast run times, small DNA fragments 100-2,000bp 8 100/10uL
Clone identification 100-2,686bp 14 100/10uL
Large size PCR or cloning 100-2,000bp 10 100/10uL
Small or large cloning application 100-5,000bp 16 100/10uL
General purpose, large digested DNA 300-10,000bp 13 100/10uL
General purpose, wide size range 100/10,000bp 19 100/10uL
General purpose, extra-large fragments 300-24,000bp 15 100/10uL
Routine DNA ladders are designed for qualitative analysis and size assessment
small fragments, quick size assessment 50-2,000bp 11 200/5uL
Quick size assessment of broad size range 50-10,000bp 16 200/5uL

exACTGene DNA Ladders: Routine DNA Ladders/RiboLadders™ RNA Standards


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