A bright chemiluminescence conjugated polymer-mesoporous silica nanoprobe for imaging of colonic tumors .

Hypochlorite acid (ClO) is one of the major reactive oxygen species (ROS) in colon cancer, providing an effective target for colonic tumor imaging. For detection of ClO and tumor imaging, poly[(9,9-di(2-ethylhexyl)-9-fluorene-2,7-vinylene)--(1-methoxy-4-(2-ethylhexyloxy)-2,5-phenylenevinylene)] (PFV--MEHPV, namely CP1) was encapsulated in mesoporous silica nanoparticles (MSNs) that were pre-modified with polyphenylenevinylene (PPV) polymerization to construct bright PPV@MSN-CP1 nanoparticles. The synthesized nanoparticles were size-stable and not cytotoxic as confirmed by FE-TEM, FE-SEM, and MTT assay. Hypochlorite oxidizes the vinylidene bond of CP1 through π-π cycloaddition to form PPV-dioxetane intermediates to generate photons. The CL quantum yield of PPV@MSN-CP1 was 16.7 times higher than that of Pluronic F-127 wrapped CP1. CL nanoparticles PPV@MSN-CP1 have good selectivity for hypochlorite detection among biological oxidants (mainly ROS). The linear range and the LOD of PPV@MSN@CP1 for ClO detection are 4-90 and 1.02 μM, respectively. Subsequently, we further coated PPV@MSN@CP1 with folic acid for tumor targeting by phospholipid wrapping. PPV@MSN-CP1@FA was successfully applied for imaging of endogenously produced ClO of tumor tissue in living animals.