Why do we keep the hydrogels in PBS to understand their stability inside the body?

We synthesised some injectable hydrogels in lab and wanted to check how would they behave inside the body. So to mimic the body conditions in vitro, we took the help of PBS.

PBS (Phosphate Buffered Saline) is a commonly used buffer solution that mimics the ionic environment and pH (~7.4) of the human body, making it suitable for studying the stability and behavior of biomaterials under physiological conditions.

So when a hydrogel is kept in PBS, it is swelling, degrading and interacting with ions the same way it would in the body.

But PBS is a way too simple mimic of the complex biological environment inside the body. It can be good to use it to understand when we just need to understand how the gel would work in the acidic environment similar to our body. But since it lacks proteins, enzymes and other components of the biological system, it may not fully represent the in vivo conditions.

Alternatively, we could use more complex media like cell culture medium or simulated body fluid (SBF) to better mimic the in vivo conditions.