Cross-linked chains of polyacrylamide, introduced as matrices for electrophoresis by Raymond and Weintraub (1959), are used as electrically neutral gels to separate double-stranded DNA fragments according to size and single-stranded DNAs according to size and conformation. Polyacrylamide gels have the following three major advantages over agarose gels: (1) Their resolving power is so great that they can separate molecules of DNA whose lengths differ by as little as 0.1 (i.e., 1 bp in 1000 bp). (2) They can accommodate much larger quantities of DNA than agarose gels. Up to 10 g of DNA can be applied to a single slot (1 cm 1 mm) of a typical polyacrylamide gel without significant loss of resolution. (3) DNA recovered from polyacrylamide gels is extremely pure and can be used for the most demanding purposes (e.g., microinjection of mouse embryos).

Nondenaturing polyacrylamide gels are used for the separation and purification of fragments of double-stranded DNA. As a general rule, double-stranded DNAs migrate through nondenaturing polyacrylamide gels at rates that are inversely proportional to the log10 of their size. However, electrophoretic mobility is also affected by their base composition and sequence, so that duplex DNAs of exactly the same size can differ in mobility by up to 10.

Denaturing polyacrylamide gels are used for the separation and purification of single-stranded fragments of DNA. These gels are polymerized in the presence of an agent (urea and/or, less frequently, formamide) that suppresses base-pairing in nucleic acids. Denatured DNA migrates through these gels at a rate that is almost completely independent of its base composition and sequence. Unlike agarose gels, polyacrylamide gels cannot be cast in the presence of ethidium bromide because the dye inhibits polymerization of the acrylamide. However, ethidium bromide can be used to stain the polyacrylamide gel after electrophoresis. Because polyacrylamide quenches the fluorescence of the dye, the sensitivity with which DNA can be detected is somewhat diminished.this cold help ur works

i will get in touch for the protocol

Dear mohammad javad Haghighatnia:

Put  the slice of acrylamide containing the desired DNA  in water and keep at 37C for  1-2 hrs the DNA  will come out.

Cross-linked chains of polyacrylamide, introduced as matrices for electrophoresis by Raymond and Weintraub (1959), are used as electrically neutral gels to separate double-stranded DNA fragments according to size and single-stranded DNAs according to size and conformation. Polyacrylamide gels have the following three major advantages over agarose gels: (1) Their resolving power is so great that they can separate molecules of DNA whose lengths differ by as little as 0.1 (i.e., 1 bp in 1000 bp). (2) They can accommodate much larger quantities of DNA than agarose gels. Up to 10 g of DNA can be applied to a single slot (1 cm 1 mm) of a typical polyacrylamide gel without significant loss of resolution. (3) DNA recovered from polyacrylamide gels is extremely pure and can be used for the most demanding purposes (e.g., microinjection of mouse embryos).

Nondenaturing polyacrylamide gels are used for the separation and purification of fragments of double-stranded DNA. As a general rule, double-stranded DNAs migrate through nondenaturing polyacrylamide gels at rates that are inversely proportional to the log10 of their size. However, electrophoretic mobility is also affected by their base composition and sequence, so that duplex DNAs of exactly the same size can differ in mobility by up to 10.

Denaturing polyacrylamide gels are used for the separation and purification of single-stranded fragments of DNA. These gels are polymerized in the presence of an agent (urea and/or, less frequently, formamide) that suppresses base-pairing in nucleic acids. Denatured DNA migrates through these gels at a rate that is almost completely independent of its base composition and sequence. Unlike agarose gels, polyacrylamide gels cannot be cast in the presence of ethidium bromide because the dye inhibits polymerization of the acrylamide. However, ethidium bromide can be used to stain the polyacrylamide gel after electrophoresis. Because polyacrylamide quenches the fluorescence of the dye, the sensitivity with which DNA can be detected is somewhat diminished.this cold help ur works

i will get in touch for the protocol

I've done crush and soak method of Molecular cloning  and all method that you said  

but I haven,t isolate any DNA. By the way thanks for requesting my question  

A classical method without crushing the gel slice is electroelution. This can be done simply by dropping the gel slice into dialysis tubing with a little buffer and placing it back in the electrophoresis chamber.

Alternatively, there are special devices, e.g. Elutrap® Electroelution System by Whatman®.

Crush and soak willalso work. Here is one of the freely available protocols:

http://groups.molbiosci.northwestern.edu/morimoto/research/Protocols/IV.%20DNA/D.%20Cloning/1b.%20Acrylamide%20crush

Thanks Dr. Uwe Borgmeyer

but We don,t have any devices to examine first method and the crush and soak by this way it doesn't any result 

You can try this:

https://www.qiagen.com/es/resources/resourcedetail?id=1426dbb4-da09-487c-ae01-c587c2be14c3&lang=en

It worked for me some years ago

How do you know the DNA was in the gel to start with. And how do you know you didn't get any DNA out of the gel?

Simple method, always worked for me:

1) with a needle, make a small hole through the bottom of a small (0.5ml) Eppendorf tube. Fill one-third of the tube with sterile loose glass wool aquarium filter (available in pet shops in many countries, you will have to autoclave it). Cut the tube lid off.

2) put the small eppenforf into a 1.5ml Eppendorf, where you will recover the DNA.

3) put the gel+band slice on top of the glass wool in the small eppendorf tube. Centrifuge 1 min. Wash the glass wool 2x TE. The DNA can be phenol/Chloroph/IAA-cleaned and ethanol-ppt'ed.

By the way, if i examine last method, i will express my result. 

Please tell me other protocol that you know 

A classic method is to crush the gel (mortar and pestle), elute in triethanolamine bicarbonate pH7, apply to a C18 column, wash with buffer, wash with buffer in 10% acetonitrile, and elute in TEA/30% acetonitrile, evaporate to dryness and resuspend in aqueous buffer.

The QIAEX II and QIAquick Gel Extraction Kit can be used to extract DNA from polyacrylamide gels. www.qiagen.com

http://www.jenabioscience.com/images/PDF/PP-202.pdf 

Thank you very much

I isolate DNA from gel by Crush & Soak method.

I've done it.

How are you proposing to carry out the sequencing?

I have always used a  quite old, but still good, mash and elute technique to extract DNA for manual sequencing. Take a blue Gilson tip and heat the very tip in a bunsen to melt it and seal the end. Then force some hydrophobic material - I used siliconised glass wool - into the narrow end. Then add the gel and mash it up against the side using a yellwo gilson tip, add buffer and seal the top with nescofulm. Stand for a period (I used overnight at 37 degrees). Finally cut off the very end of the tip with a scalpel, put the tip into ae eppendorf tube and spin at low speed to elute the liquid. Finally do an ethanol precipitation. From memory, I think thais is basically the method described by Maxam & Gilbert (1980) Methods in Enzymology 65, 499.

I extract DNA by this method.

Hi, please use crush and soak method as described in Sambrook et al., (2000; Molecular cloning).

Kit from Promega Inc or Qiagen works best...!!