Try culturing the cells in 6 well plates so they can easily attach to each other, also consider using high adhesive plates to fast track the attachment. In terms of detachment, you can incubate the cells in trypsin for no more that 10 minutes and gently tap the flask on the side to mechanically detach them

Hello Giulia Micheloni

Yes, I agree trypsinization of SW1116 cells can be challenging as they are known to be relatively strongly adherent. I would suggest the following.

1. SW1116 cells should be sub cultured when they reach about 80% confluence, but before they reach 90% confluence.

2. Thoroughly wash the cell monolayer with PBS to remove any serum, which can inhibit trypsin. Use a standard 0.25% trypsin with 1 mM EDTA solution. If cells are difficult to detach, try washing the cells with warm PBS before adding trypsin. If cells are still resistant, incubation at 37°C may facilitate dispersal. Gently tapping the sides of the flask can help dislodge the cells.

3. If some cells remain attached, trypsinize again with a fresh solution.

4. If trypsinization is consistently difficult, some suggests the use of cell scraper as an alternative. But I don’t recommend the use of cell scraper. Scraping involves physically dislodging cells, which can rupture the cell membrane and damage cellular structures. If you need high cell viability, or if you are interested in membrane-associated proteins, scraping may not be the right choice.

5. If cells do not detach by using trypsin, do not attempt over exposure (not more than 5 mins of trypsin exposure). Excessive trypsin exposure can strip cells of vital membrane proteins, disrupt the cytoskeleton, and alter the cell's internal environment, ultimately impacting cell viability. If adherent cells detach from their culture surface and fail to reattach, they will typically die because attachment provides these cells with necessary signals for survival, growth, and differentiation thereby maintaining their normal functions.

Hope the above suggestions help!

Good Luck!

SW1116 cells can be challenging to culture, especially during early passages, as they are moderately adherent and sensitive to the stress of subculturing. If they are difficult to detach with trypsin, consider using 0.05% trypsin-EDTA with a slightly extended incubation time (5–8 minutes), carefully monitoring under a microscope to avoid overexposure. Gentle tapping and minimal pipetting help prevent cell damage. Poor reattachment after splitting can often be improved by seeding at a lower split ratio (1:2 or 1:3) with higher cell density, using complete medium supplemented with 10–20% FBS, and optionally adding non-essential amino acids or sodium pyruvate. If attachment remains problematic, coating culture surfaces with collagen I or poly-L-lysine may enhance adherence. It is also important to avoid over-confluency, as this can affect both detachment and viability. With careful handling, SW1116 cells typically stabilize within a few passages.