Polystyrene-Hemin Dots for Chemiluminescence Imaging

Chemiluminescence (CL) imaging has high sensitivity with significantly increased signal-to-background ratio due to no interferences of light source and autofluorescence. However, it is still a great challenge to design and synthesize a highly sensitive CL imaging probe that acquires intensive and long-lasting emission. Here, we demonstrate mimic-enzyme catalytic CL polymer dots (polystyrene (PS)-hemin dots) consisting of hemin, polystyrene, and amphiphilic polymer. CL emission catalyzed by PS-hemin dots increased tremendously, 6000-fold more than that of peroxide hydrogen CL substrate direct reaction and over 5 h emission. These properties are mainly due to a large number of hemin molecules in a single nanoparticle, high-catalytic activity of PS-hemin dots and slow-diffusion-controlled heterogeneous reaction. PS-hemin dots also possess good stability, excellent biocompatibility, and ultrasensitive response to hydrogen peroxide. The conjugates of PS-hemin dots and integrin-targeting ligand cyclic RGD (arginine glycine aspartic) were used for CL imaging of normal and cancerous cells based on the specific reaction between the integrin alpha(v)beta(3) and cyclic RGD. PS-hemin dots were also successfully used for real-time imaging reactive oxygen species levels in normal and inflammatory mice. PS-hemin dots as highly sensitive CL probes have great potential in bioassays and bioimaging.