Hello Hong Kit Lim

I feel that the A549 cells were not frozen in a proper manner. Usually when cells are not frozen properly following standard protocol they tend to show some changes in their characteristics after thawing. Why don't you thaw another vial belonging to a different batch? May be your problem could be solved.

Best Wishes.

Dear Hong!

You have good A549 cells. The morphology of the cells may differ depending on the reagents used (the composition of the culture medium), the culture dishes used. For example, in some plates or dishes with high adhesion, cells will be more spread out, elongated.

This also applies to vials or cups, coated tablets (collagen, laminin, etc.).

In other conditions, with a low-adhesive coating, the cells will be more rounded.

Cell morphlogy can also depend on their density. If the density is high, then the cells will be adjacent to each other and are more round, at the low density of seeding, the cells will be flatter.

Please You look at following protocol:

Article Long Term Culture of the A549 Cancer Cell Line Promotes Mult...

Cell Culture

Authentic A549 cells (European Collection of Cell Cultures (ECACC), Salisbury, UK), catalogue number 86012804, were cultured in either Ham’s F12 Nutrient Medium (Ham’s F12) or Dulbecco’s Modified Eagles Medium (DMEM) (both from Sigma Aldrich, Dorset, United Kingdom) supplemented with 2mM L-Glutamine and 10% v/v Foetal Bovine Serum (FBS) (Hyclone SH30071.03 (Hyclone Laboratories, Utah, USA). Proliferative cultures were incubated at 37°C in a humidified 5% CO2 incubator. Trypsin was inactivated by the addition of growth medium before seeding into fresh flasks at densities of 1.5-2x104 cells/cm2.

A549...appear good