you might be interested in using a scaled down version of this method

https://bitesizebio.com/44255/isolating-monocytes-from-whole-blood-a-step-by-step-guide/

Dear Lucia,

I would say it depends on the cell number you are after.

In my opinion, is the best way to use bone marrow derived monocytes if you need many of them.

I hope you do not mind that I take the chance to shamelessly recommend work, that I was a apart of.

PMID: 21705645; PMID: 23573361; PMID: 25591000

Best wishes

Soenke

Dear Dr. Lucia Fuentes,

You may try the protocol provided below.

You need to first obtain peripheral blood mononuclear cells (PBMCs) as follows.

1. The mouse may be killed and bled by cardiac puncture into a heparinized syringe with a 25-gauge needle.

2. The blood may be diluted by adding an equal volume of 0.9% saline and layered over a NycoPrep 1.077 animal cushion.

3. You may perform centrifugation at 586 × g (no brake) for 15 min. 

4. Mononuclear cells can then be collected from the interface between the plasma and the NycoPrep cushion.

5. These cells may then be resuspended in Tris-buffered ammonium chloride (TBAC)  lysis buffer, which is made by mixing 0.15 M ammonium chloride and 0.17 M Tris at a ratio of 9:1 before adjusting the pH to 7.2 and filter sterilization.

6. The red blood cells may be lysed following 5 min incubation in TBAC buffer for 5 min at room temperature followed by three washes in RPMI-1640.

7. The PBMCs so obtained are then resuspended in RPMI-1640 medium supplemented with 10% fetal bovine serum and incubated for 30 min at 4°C with continuous agitation.

(Please note: It has been observed that monocytes spontaneously and rapidly aggregate in vitro at 4°C, which is called the cold-aggregation procedure).

8. Monocytes then spontaneously sediment. You may perform two more successive rounds of cold aggregation.

Regards,

Malcolm Nobre

Thank you! i'm starting to work on your suggestions