ChIP in a tip
A pipette tip ( 20 ) containing a rigid porous matrix ( 22 ) on which a ligand is immobilized, the ligand being capable of binding to a protein associated with chromatin; the rigid porous matrix being positioned within the pipette tip such that, in use, chromatin in a liquid sample passing through the pipette tip is retained by the rigid porous matrix is described. A method of isolating chromatin from the liquid sample using the pipette tip and the use of the pipette tip in a chromatin immunoprecipitation assay are also described.
1. A pipette tip having:
an open upper end adapted to engage a pipette;
an open lower end; and
a through passageway in fluid communication with the upper and lower ends;
the pipette tip being configured such that, in use, a liquid sample is capable of passing through the tip both by being drawn in through the lower end by the application of reduced pressure, and being expulsed out of the lower end by the application of increased pressure;
the pipette tip containing a rigid porous matrix on which a ligand is immobilized, the ligand being capable of binding to a protein associated with chromatin;
the rigid porous matrix being positioned within the pipette tip such that, in use, chromatin in a liquid sample passing through the pipette tip is retained by the rigid porous matrix;
the rigid porous matrix being positioned within the lower half of the pipette tip;
wherein the rigid porous matrix comprises a sintered thermoplastic polymer, the matrix being functionalized at a surface after sintering, the functionalisation providing functional groups on the surface which facilitate the attachment of the ligand.
2. A pipette tip according to claim 1 , wherein the rigid porous matrix is positioned within the pipette tip such that, in use, the liquid sample is capable of multiple passes through the tip, by multiple drawings through the lower end and multiple expulsions out of the lower end.
3. A pipette tip according to claim 1 , wherein the rigid porous matrix is positioned within the lowest quarter of the pipette tip.
4. A pipette tip according to claim 1 , wherein the rigid porous matrix is in the form of a filter disc or frit.
5. A pipette tip according to claim 1 , the cross-sectional area of the pipette tip narrowing towards the lower end thereof.
6. A pipette tip according to claim 1 , the pipette tip being tapered towards the lower end thereof.
7. A pipette tip according to claim 1 , having a frusto-conical or frusto-pyramidal shape.
8. A pipette tip according to claim 1 , having a volume of 1 μl to 10 ml.
9. A pipette tip according to claim 1 , having a volume of 5 μl to 1 ml.
10. A pipette provided with a tip according to claim 1 .
11. A pipette according to claim 10 , wherein the tip is an integral part of the pipette.
12. A pipette according to claim 10 , wherein the tip is manufactured separately from the pipette and attached to the pipette prior to use.
13. A pipette according to claim 10 , selected from the group consisting of an air displacement pipette, a positive displacement pipette, a multichannel pipette, a pipetting syringe, a glass micropipette, a microfluidic pipette, a microsyringe, a syringe and a cannula.
14. A kit comprising a pipette tip as defined in claim 1 , and one or more buffers, solutions or reagents suitable for performing a chromatin immunoprecipitation assay.