Synthesis, characterization, and drug release properties of enzyme-responsive oxamide-bridged mesoporous organosilica nanoparticles

In this study, we report a novel enzyme-responsive mesoporous organosilica nanocarrier (MON) and its drug delivery properties in the presence of the trypsin enzyme. The mesoporous organosilica nanocarrier was synthesized by using the oxamide bridged bissilyl compound (2) and 1,4-bis(triethoxysilyl)benzene (BTSB). To compare the enzyme responsiveness of MON, the reference periodic mesoporous organosilica (PMO) nanocarrier was also synthesized using BTSB only. The structural determinations of the synthesized organic compounds were carried out by 1H, 13C-NMR, FT-IR, and MS, while FT-IR, XRD, SEM, EDS, transmission electron microscopy (TEM), TGA, and N2 sorption analyses were used for the characterization of MON and PMO. Drug loading and release properties of both nanocarriers were studied by using curcumin as a model drug. The loading capacities were determined as 11.4% for MON and 2.9% for PMO. The enzyme-responsive drug release of the drug-loaded nanocarrier curcumin-loaded MON (Cur@MON) was investigated in the presence and absence of the trypsin enzyme at physiological pH. The results showed that the oxamide structure undergoes selective cleavage of amide bonds in the presence of the trypsin enzyme, causing the nanocarrier to release curcumin.