Until recently, semi-dry blotters have not been extensively used for Northern or Southern blotting, mainly because it is an even longer process than Western blotting
The use of semi-dry blotters to accomplish the transfer of nucleic acids (Northern and Southern blotting) and proteins (Western blotting) from electrophoresis gels to inert membranes such as PVDF, nitrocellulose or nylon, is well documented. Primarily it allows a permanent record of the gel to be stored, enables further analysis and provides for further probing by nucleic acid hybridisation (Northern and Southern blotting) or antibody reactivity (Western blotting).
However, in most laboratories semi-dry electroblotting is usually associated with blotting proteins (Western blotting).
This technique provides fast, effective and economical permanent transfer of proteins from acrylamide gels onto membranes such as PVDF.
Typically, semi-dry blotting transfer takes from 15 to 30 minutes, significantly faster than wet electroblotting techniques which take around three hours.
In addition to saving time in the lab, buffer volumes required are also significantly reduced.
Until recently, semi-dry blotters have not been extensively used for Northern or Southern blotting, mainly because it is an even longer process than Western blotting, typically performed overnight.
More commonly, Southern and Northern blotting has been performed by the slow technique of capillary action blotting. Electrophoresis specialist Scie-Plas offers a range of semi-dry blotters which incorporate features to ensure that speed and ease-of-use does not compromise quality of results.
For example, an even electrical field and corrosion resistance is achieved by using a platinised titanium anode and stainless steel cathode. These features combine to prevent deposits being placed on the membrane and so greatly reducing background or spurious results. These units, which are manufactured from rugged acrylic components and comply with all statutory safety regulations, are available in two sizes, 10x10cm and 20x20cm.
Both units allow blotting of mini and maxi sizes of gel respectively, with the 10x10cm system being a very cost-effective option for laboratories working to a very tight budget.
The 20x20cm format can also be used for blotting multiple small format gels, while the capacity of both systems can be increased by stacking gels interspersed with dialysis membrane.
