The other interesting result is that the Bjerrum length of water l B = 0.7 nm. In the case of synovial fluid which is mostly made up of Hyaluronic acid with chemical formula (C 14 H 21 N O 11 ) n , each monomer is made by 47 atoms attached through covalent bonds. If we consider that this atoms form a packed sphere and we take the size of each atom the average value 0.0914 nm which is the size of a carbon atom, then by using R = a N 1/3 relation for the radius of a packed sphere, we get R = 0.33 nm for the radius of a Hyaloronic acid monomer. This suggests that the diameter of a typical Hyaluronic acid monomer is roughly 1.0 nm. Therefore, with a good approximation, we can say that the Bjerrum length of water is l B = 0.7 a. As it is seen from the results, the Bjerrum length of water is way above the critical Bjerrum length in which the counterions get absorbed by the brush. It means that in water at room temperature, the charged particles are in the highly condesed regime and the electrostatic interactions are completely screened. So, in biological systems there is no charged particle moving around freely. This property gives rise to many effects like self-healing, blood clots, sedimentation in the vessels wall etc. Note that, the Bjerrum length of blood is equal to that of water. Hence, this study suggests that by tunning the Bjerrum length in Polyelectrolyte brushes, we can control the amount of the counterions absorbed by the brush. This effect could have potential applications in biotech, industry etc. The results of this article could be extended to verify the equation of state of a Polyelectrolyte brush bilayer but up to the present day, this task is apparently very diificult due to complexity of the equations and integrals.