Methods for purifying biological cells

1. A method for purifying viable cells, comprised of:

a) providing at least one column, wherein the column is comprised of a packed bed of medium, wherein the packed bed of medium has a bed volume, wherein the packed bed of medium is retained between two frits, a lower frit and an upper frit, wherein the packed bed of medium is comprised of particles, wherein the particles are comprised of an affinity group, wherein the affinity group is an antibody or a FAB;

b) providing a biological sample, wherein the sample is comprised of viable cells, wherein the viable cells are not labeled with antibodies, wherein the biological sample has a sample volume, wherein the sample volume is larger than the bed volume;

c) aspirating the biological sample in an upward direction through the column, wherein the sample is aspirated through the lower frit, into the packed bed of medium and then through the upper frit;

d) expelling the biological sample by reversing the flow direction, wherein the biological sample is expelled in a downward direction through the upper frit, into the packed bed of medium and then through the lower frit;

e) repeating steps (c) and (d) multiple times, wherein the biological sample is not incubated on the column, whereby a portion of the viable cells are captured by the antibody affinity groups on the particles in the packed bed of medium;

f) passing a wash solution through the column; and

g) eluting the cells by passing an eluent through the column, wherein the eluted cells are intact and viable, wherein the eluted cells maintain their integrity, wherein the method is at least partially performed by a timed computer-controlled program, and wherein the entire method is performed in less than 30 minutes.

2. The method of claim 1 , wherein the column is a pipette tip.

3. The method of claim 1 , wherein the sample is comprised of bacterial cells or plant cells.

4. The method of claim 1 , wherein following step (f) the captured cells are labeled on the column.

5. The method of claim 1 , wherein the antibodies are covalently attached to the particles with a linker.

6. The method of claim 1 , wherein the antibodies are tagged with a drug.

7. The method of claim 1 , wherein the particles are comprised of protein A or protein G.

8. The method of claim 1 , wherein the method is used for negative selection and viable cells captured by the antibody affinity groups are not the cells of interest.

9. The method of claim 1 , wherein the eluted cells are selected from the group consisting of tumor cells, circulating tumor cells, immune cells, sperm cells, white blood cells, cancer cells, E. coli cells, T cells, B cells and stem cells.