The Mechanism Behind Beauty: Golden Ratio Appears in Red Blood Cell Shape

In the past two decades, under the conditions that both the osmotic pressure ∆p and tensile stress λ equal zero, a rigorous solution (RS) of human red blood cell (RBC) with a minus spontaneous curvature c0 has been derived with Helfrich model. And, by fitting with observed shapes of RBC, c0R0 has been predicted to be -1.62 as minus golden ratio, where R0 is the radius of a sphere with the same area of RBC. In this Lett., it is also found ρmax /ρB ≈ 1.6 shows a approximately beautiful golden cross section of RBC, where ρmax is the radius of RBC and ρB is the radius at maximal thickness of RBC. With a complete numerical calculation, we find the mechanism behind the beauty that minus golden ratio of c0R0 is the balance between economical surface area and enough deformability to pass spleen, the so called “physical fitness test”.