Figure. Morphological characterization of MBP and MBP-Ca. Scanning electron microscopic images of MBP (A) and MBP-Ca (B). Surface elemental compositions of MBP (C) and MBP-Ca (D). Particle size distribution of MBP and MBP-Ca (E). Asterisk indicates statistical significance (** p < 0.01) compared to the MBP control group.