Difference Between PBS and HBSS (With Table)

PBS stands for Phosphate Buffered Saline. It is a water-based buffer salt solution that helps to maintain a constant pH level in a sample. The pH level of this solution is approximately 7.4. PBS is isotonic in nature and is not toxic to most cells.

HBSS stands for Hank’s Balanced Salt Solution. It is a liquid or powdered solution used to maintain osmolality and pH levels in biological applications. They are also responsible for the short-term maintenance of cells outside of the growth medium. HBSS is composed of several electrolytes which are found in the intracellular and extracellular compartments.

Comparison Table Between PBS and HBSS

What is PBS?

PBS stands for Phosphate Buffered Saline. It is a water-based buffer salt solution that helps to maintain a constant pH level in a sample. The water level and ion concentrations of the PBS solutions match the human body which means PBS solutions are isotonic in nature.

Since PBS solutions are not toxic to cells, they have many applications including substance dilution and disengage clumped cells, etc. In recent years, PBS solutions have been high in demand because they are used as an alternative to viral transport medium for the storage of RNA viruses including SARS-CoV-2 or Corona Virus.

A PBS solution can be made by various methods. If the buffer is used on live tissue then the preparation needs Pottasium Chloride or Magnesium Chloride whereas if the buffer is used on fixed tissue then neither Pottasium Chloride nor Magnesium Chloride is required. While preparing, the pH level can be adjusted using hydrochloric acid or sodium hydroxide.

The most common ingredients of a PBS solution include NaCl, KCl, Na₂HPO₄, and KH₂PO₄ in precisely calculated amounts. PBS solutions can also be prepared by utilizing commercially made PBS buffer tablets or capsules. PBS solutions are stored either at room temperature or in the refrigerator.

What is HBSS?

HBSS stands for Hank’s Balanced Salt Solution. This solution was named after the biologist John H. Hanks that formulated them in 1940. This solution is used as a buffer system in cell culture and helps in maintaining the optimum pH levels or cellular growth. The optimum pH values range from 7.0 to 7.4.

Since HBBS solutions contain glucose and sodium bicarbonate, they are used for short-term cell maintenance outside of the growth medium. These solutions are also used for a variety of cell culture applications such as washing cells, transporting cells, or diluting cells. HBSS solutions formed with calcium and magnesium are used as transport media or for reagent preparation.

An HBSS solution is prepared from a powdered base medium combined with tissue water of culture-grade. The common ingredients of an HBSS solution are inorganic salts, glucose or pyruvate, phenol red, and sodium bicarbonate. After preparation, samples of HBSS solutions are tested to confirm the absence of bacterial or fungal contamination

HBSS solutions are delicate and are supplied in gamma-irradiated, sterile bottles. HBSS solutions are stored at a low temperature of 4-8 celsius degrees and away from direct light. They are also more dangerous to make as compared to PBS solutions because human cells have bio-hazardous materials.

Main Differences Between PBS and HBSS

1. A PBS solution is generally easier to make whereas an HBSS solution’s preparation process can be dangerous and hence, extra precautions are important.
2. PBS solutions can be stored at a temperature ranging from 15 to 30 degrees celsius whereas HBSS solutions are stored at a temperature ranging from 4 to 8 degrees celsius.
3. PBS solutions can be prepared in liquid form only while HBSS solutions can be prepared in both liquid and powdered form.
4. PBS solutions are pure by default. On the other hand, HBSS solutions need to be checked for bacterial or fungal contamination.
5. PBS solutions are not toxic to cells whereas HBSS can cause cell death.

Conclusion

Both PBS and HBSS are saline solutions used mostly in molecular biology, biochemical experiments, and for research in biological medicines. While conducting an experiment, both solutions are placed in a Petri dish with a cell or tissue. The solution holds the cells while examining or for use during the experiment. Even though the two are separate saline solutions, they can also be used interchangeably under favorable conditions. However in such cases if the sample is needed in powdered form, then HBSS solution is picked as PBS solution is only in liquid form.

PBS is mostly preferred to be prepared in labs as the composition of ingredients can be varied if needed and it is also safe to do so as PBS solution does not harmfully affect cells. HBSS solution on the other hand is preferred directly from the markets as it is dangerous to prepare it in a lab considering its delicacy and possible contamination from bacteria or fungus. Moreover, achieving favorable conditions requires more resources as it can only be stored at a low temperature.

Although the basic purpose of both these saline solutions is the same, PBS’ demands have increased over the last few years as it can be used as a viral transport medium for the storage of RNA viruses including the Corona Virus.

References

1. https://journals.asm.org/doi/full/10.1128/JCM.00590-20
2. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-9657.1991.tb00187.x