Question

Bromocresol green to be added before autoclave or after?

Answer 1

Most of the commercially available culture media include phenol red as a pH indicator, which allows constant monitoring of pH [24]. During the cell growth, the medium changes color as pH is changed due to the metabolites released by the cells. At low pH levels, phenol red turns the medium yellow, while at higher pH levels it turns the medium purple. Medium is bright red for pH 7.4, the optimum pH value for cell culture. However, there are certain disadvantages of using phenol red as described below: 1) Phenol red mimics the action of some steroid hormones, particularly estrogen [25]. Thus it is advisable to use media without phenol red for studies using estrogen-sensitive cells like mammary tissue. 2) Presence of phenol red in some serum-free formulations interferes with the sodium-potassium homeostasis. This effect can be neutralized by the inclusion of serum or bovine pituitary hormone in the medium [26]. 3) Phenol red interferes with detection in flow cytometric studies.