An overview of incorporated materials that have increased or inhibited the MSN degradation rate, their responding stimulus and the mechanism of degradation.

Material	Sensitive to	Mechanism/effect on degradation	Ref.
Ions: Ca2+, Al3+, Mn2+, and Zn2+	Acidic pH and GSH	→Ion doped MSNs degrade by OH− catalyzed by acids	26, 64 and 119
	Enzymatic hydrolysis	→Urea bridged siloxane is hydrolyzed by enzymes	120
	Enzyme degradable	→Oxamide bridge is cleaved by enzymes to form carboxylates and ammonium siloxanes	121
	GSH	→Disulphide bridge is reduced by glutathione and other reducing agents to form thiol siloxanes	36 and 56
	Redox (GSH/ROS)	→Diselenium bridge is cleaved by oxidation to form selenic acid siloxanes, reduction to form selenol siloxanes or X-ray irradiation	122, 123 and 124
	Singlet oxygen (1O2) degradable	→Anthracene bridge is cleaved by cycloaddition of singlet oxygen (1O2) to produce anthraquinone	125
	UV-light	→2-Nitrobenzyl ether bridge is cleaved by exposure to UV-light	126
	Non-degradable	→C C bridge decreases the MSN degradation rate due to increased stability compared to siloxane bonds	54