Vertical SDS-PAGE Electrophoresis System

What is the Vertical SDS-PAGE Electrophoresis System?

A vertical SDS-PAGE system runs one or two 1 mm polyacrylamide gels in a buffer tank with platinum wire electrodes, resolving proteins from 10 to 200 kDa. It is the standard workhorse for purity and molecular weight determination in protein laboratories.

Overview

The system consists of a casting stand, a gel cassette assembly that forms a sealed upper buffer chamber, and a lower tank holding the anode. The electrode assembly holds one or two glass plate sandwiches, and the sample wells are formed by a comb. Voltage is applied between the upper and lower buffer chambers, and the discontinuous Tris-glycine buffer system sharpens bands as they enter the resolving gel. Typical conditions are 100–200 V constant voltage for 45–90 minutes, with an expected 10–15 mA per gel. Optional cooling is available for high-voltage or long runs, and one gel can be blotted while another is running. Plate and comb formats accept 10, 12 or 15 wells, and precast gels can be used in place of hand-cast plates.

How does it work?

In SDS-PAGE, the sample is denatured with sodium dodecyl sulfate and a reducing agent so that proteins unfold and acquire a uniform negative charge proportional to their length. When an electric field is applied, all proteins migrate toward the anode, and the polyacrylamide mesh sieves them so that migration distance depends mainly on molecular weight. A discontinuous buffer system with stacking and resolving gel layers concentrates proteins into a sharp band before separation. Isoelectric focusing instead uses a pH gradient and separates proteins according to their isoelectric point, where net charge is zero and migration stops. Two-dimensional electrophoresis combines the two, separating by charge first and by size second, which resolves thousands of protein spots. Capillary systems perform SDS or charge separation in a narrow capillary with on-line absorbance or fluorescence detection, replacing staining with quantitative detection.

What are the key features?

• Accepts one or two 1 mm hand-cast or precast gels
• Upper buffer chamber seal without extra gaskets
• Comb formats for 10, 12 or 15 sample wells
• Constant voltage or current operation up to 200 V
• Optional cooling core for high-voltage runs
• Colour-coded electrode assembly to prevent polarity reversal

What are the technical specifications?

A typical vertical sds-page electrophoresis system configuration offers gel size of approx. 80 x 100 mm, gel thickness of 0.75–1.5 mm, gels per run of 1 or 2, well formats of 10, 12 or 15 wells, maximum voltage of up to 200 V and maximum current of up to 200 mA. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Vertical SDS-PAGE Electrophoresis System is used in protein purity assessment by densitometry, molecular weight determination against a ladder, recombinant protein expression checks and sample preparation for western blotting. Across the wider Protein Electrophoresis class, laboratories also deploy it for protein purity and molecular weight determination, recombinant protein expression analysis and two-dimensional proteome profiling.

Which standards and certifications apply?

Relevant standards and methods include USP <1057>, Ph. Eur. 2.2.31, Ph. Eur. 2.2.34, IEC 61010-1, ISO 17025 and ISO 15189. Certification candidates for this model are CE, ISO 9001 manufacturing and IEC 61010-1 safety; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Acrylamide is a neurotoxin and suspected carcinogen, so powder handling and gel casting should be performed in a fume hood or with ready-to-use precast gels, and gloves must be worn. Buffer pH and ionic strength affect stacking and resolution, so working buffers should be prepared fresh and not reused excessively. Consistent sample loading, reducing agent freshness and heating time determine how sharp bands appear. Gels should be run within the recommended voltage and current limits, and temperature control matters for high-voltage runs because Joule heating distorts bands. Staining and destaining protocols must be standardised for comparative densitometry, and images used for purity calculations should be captured in the linear range of the camera. Keep records of gel percentage, running conditions and staining for traceability.

How do I select the right Vertical SDS-PAGE Electrophoresis System?

Select a vertical SDS-PAGE system for routine purity and molecular weight work where standard 1 mm gels and up to 15 samples per gel are sufficient. Specify gel size and thickness, well format, voltage and current limits, cooling options and precast gel compatibility.

How does it compare with other Protein Electrophoresis variants?

Start with the purpose. For routine purity and molecular weight, a vertical SDS-PAGE system with 1 mm gels and 10–15 wells covers most needs and is inexpensive. Mini systems reduce buffer and sample consumption, run faster and are convenient for immunoblotting, at the cost of lower resolution for closely spaced bands. Multichannel systems process 6 to 12 gels in one tank when screening many samples. Two-dimensional electrophoresis is chosen when complex proteomes must be resolved, and it requires an isoelectric focusing first dimension plus consistent sample preparation. Capillary systems give numerical purity results and are preferred where regulated release testing, low sample volume or full automation is required. Check gel percentage and gradient availability, maximum voltage and current, cooling provisions, glass plate compatibility and whether precast gels are supported.