drugs, such as Ibuprofen, Amoxicillin, Gentamicin, Captopril, or even large protein drugs. Hydrogels – which belong to one category of widely employed polymer-drug matrices – are cross-linked macromolecular networks swollen in water or biological fluids. Due to their good biocompatibility and sensitivity in the physiological or biological environment, hydrogels have been found in numerous applications in the fields of biology and medicine including ophthalmological devices, biosensors, scaffold, and controlled drug delivery systems.

For the first time, a team of NUS researchers has successfully combined these two types of interesting materials together to fabricate a pH-sensitive drug delivery system. Figure 1 shows the TEM images of mesoporous silica before and after being encapsulated with hydrogel. It can be seen that after being encapsulated with hydrogel, the parallel channels of mesoporous materials are covered by hydrogel (Figure 1(c)), and from a cross-sectional view, a thick layer of PAA (around 10 nm) could be observed on the outer surface of SBA-15 (Figure 1(d)).