Abstract: This invention relates to a simple and rapid method for the extraction and purification of small RNA from a sample solution. Accordingly, a sample is first mixed with an organic solvent to form a mixture containing the solvent. The mixture is applied to a first mineral support for large RNA to bind. The filtrate is collected which contain unbound small RNA, and is mixed with a second organic solvent to form a second mixture containing the second solvent. This second mixture is applied to a second mineral support for small RNA to bind. After a wash step, the small RNA is eluted. Also provided is a method for the isolation of large RNA, by eluting the large RNA from the first mineral support. In addition, total protein is present in the filtrate and can be isolated by a conventional method.

Abstract: The invention provides systems, methods and kits for the separation and/or purification of double-stranded and single-stranded nucleic acids from the same sample. The method includes first mixing a sample containing both double-stranded nucleic acid and single-stranded nucleic acid with a solution including a chaotropic salt and a non-ionic detergent to generate a mixture; then applying the mixture to a first mineral support for double-stranded nucleic acid to bind; and collecting the flow-through which contains unbound single-stranded nucleic acid. The method further includes diluting the non-ionic detergent of the flow-through, and applying the diluted flow-through to a second mineral support for the single-stranded nucleic acid to bind. Alternatively the flow-through can be mixed with a lower aliphatic alcohol prior to loading of the second column. The double-stranded and the single-stranded nucleic acids can be eluted from the mineral supports respectively.

Abstract: The invention provides systems, methods and kits for the separation and/or purification of double-stranded and single-stranded nucleic acids. The method includes first mixing a sample containing the double-stranded nucleic acid and the single-stranded nucleic acid with a pH-neutral, buffered solution consisting essentially of a chaotropic salt and a pH buffer to generate a mixture; then applying the mixture to a first mineral support for the double-stranded nucleic acid to bind; and collecting the flow-through which contains unbound single-stranded nucleic acid. The method further includes adjusting the pH of the flow-through to an acidic pH, and applying the acidified flow-through to a second mineral support for the single-stranded nucleic acid to bind. Alternatively the flow-through can be mixed with a lower aliphatic alcohol prior to loading of the second column. The double-stranded and the single-stranded nucleic acids bound can be eluted from the mineral supports respectively.

Abstract: The invention provides systems, methods and kits for the separation and/or purification of at least two cellular components selected from genomic DNA, RNA and proteins. The method includes first lysing a biological sample to generate an aqueous solution containing the cellular components; then applying the aqueous solution to a first mineral support under conditions for genomic DNA to bind; and collecting the flowthrough which contains unbound total RNA and proteins. The method further includes applying the flowthrough to a second mineral support under conditions for RNA to bind, and collecting the flowthrough which contains proteins. The genomic DNA and total RNA bound can be eluted while the protein in the flowthrough can be further purified. Further the total RNA isolated could be used to isolate small RNA such as microRNA.