Hollow Porous Polymeric Nanospheres of a Self-Enhanced Ruthenium Complex with Improved Electrochemiluminescent Efficiency for Ultrasensitive Aptasensor Construction

Although Ru(II)-complex-based bulk nanomaterials have received considerable attention in electrochemiluminescent (ECL) assays owing to their strong ECL signals, the ECL efficiency of these nanomaterials was quite low since the bulk nanomaterials brought about a serious inner filter effect and excess inactive emitters. Herein, hollow porous polymeric nanospheres of a self-enhanced ruthenium complex (abbreviated as Ru-HPNSs) were prepared with a polyethylenimine-ruthenium complex precursor to greatly decrease the inner filter effect and minimize inactive emitters, which significantly improved the ECL efficiency. On the basis of the novel Ru-HPNSs as efficient ECL tags and target-catalyzed hairpin hybridization as signal amplification strategy, an ultrasensitive ECL aptasensor was constructed for the detection of mucin 1 (MUC1), which showed excellent linear response to a concentration variation from 1.0 fg/mL to 100 pg/mL with the limit of detection down to 0.31 fg/mL. It is worth mentioning that this work opened a new avenue for developing high-performance ECL nanomaterials as well as ultrasensitive ECL biosensors for clinical and biochemical analysis.