Programmed microcapsule-type matrix metalloproteinase-2 (MMP-2)-responsive nanosensor for in situ monitoring of intracellular MMP-2

Abstract Sensitive detection, especially in situ monitoring of intracellular MMP-2, is extremely desirable for cancer early diagnosis, evaluation of therapy, and discovery of the new anti-cancer drug. Herein, a programmed microcapsule-type MMP-2 responsive nanosensor based on mesoporous silica nanoparticles (MSN) is developed to realize in situ imaging monitoring of intracellular MMP-2. In the wrapping anti-MMP-2 antibody sealed microcapsule-type nanosensor, a black hole fluorescence quencher (BHQ-3) is covalently combined onto the inner walls of the MSN mesopores, and the fluorescein Cy5 is loaded in the cavity of MSN, resulting in fluorescence “OFF” state. With the existence of MMP-2, the anti-MMP-2 antibody which acts as a “bio-lid” could detach from the surface of the nanosensor owing to the binding MMP-2 with the antibody, leading to the release of the fluorescein Cy5 to produce fluorescence “ON” state. The prepared programmed microcapsule-type MMP-2 responsive nanosensor is capable of sensitive in situ imaging monitoring of intracellular MMP-2 and is further verified by tracking the change of intracellular MMP-2 level in response to MMP-2-repressive drugs. Thus, the nanosensor give a platform for in vivo detection of biomarkers for diagnosis, evaluation of therapy, and discovery of the new anti-cancer drug.