Aluminum hydroxide (Al(OH)3) suppresses self-healing of PLGA. Effect of encapsulation of aluminum hydroxide (Al(OH)3) or calcium phosphate (CaHPO4) in PLGA microspheres on PLGA healing. Scanning electron microscopic images of Al(OH)3-trehalose-PLGA (A), blank (trehalose/PLGA) (B), and CaHPO4/trehalose/PLGA (C) microspheres before and after active self-healing microencapsulation process. Image A, B, and C respectively correspond to ASM-17, B-1, and ASM-18 in Table 1. Microspheres (20-63 μm in size) were incubated with 0.4 mL of 1 mg/mL OVA in 10 mM MOPS buffer (pH 7.4) under mild agitation at 25 and 43 °C respectively for 24 and 48 h.