Enhanced chemiluminescent resonance energy transfer in hollow calcium phosphate nanoreactors and the detection of hydrogen peroxide

Chemiluminescent nanoreactors (nano-CRET) that exhibit unusually efficient chemiluminescence resonance energy transfer to a co-encapsulated fluorophore when reacted with hydrogen peroxide are described. The nanoparticles have a mean size of 150 +/- 20 nm and consist of a calcium phosphate shell surrounding a hollow core that is filled with a solution containing luminol, haematin and fluorescein. Steady state and stopped-flow fluorescence spectroscopy were used to characterize their H2O2-dependent emissions. The results demonstrated a significant improvement in resonance energy transfer efficiency between the chemically excited luminol intermediate and fluorescein dye over that in solution when luminol and fluorescein were co-encapsulated inside nano-CRET. Such nano-CRET particles can improve the ease and accuracy of H2O2 sensing in many life science and forensics applications, particularly where reagent degradation or quenching of the chemiluminophore emission by other molecules impedes quantitative analysis.