Fig. 4.

Accumulated detection of phosphorescence augmentation in IPA–aptamer hybrid assembly with specific target recognition. a SEM image of IPA–aptamer hybrid assembly (scale bar: 5 μm). b XRD spectra of IPA crystal (yellow line), IPA recrystallized using reprecipitation method (green line), and IPA–aptamer hybrid obtained using reprecipitation method (red line). c CLSM images of IPA–aptamer hybrid assembly after exposure to nucleolin. IPA was excited by a 405 nm laser, and emission was filtered in a range of 410–500 nm (left). PE-labeled nucleolin was excited with a 555 nm laser, and emission was filtered in a range of 580–640 nm (right) (scale bar: 20 μm). d Relative PL intensity of IPA without (dashed bar) or with (full filled bar) aptamer after exposure to various proteins with same concentration of 200 nM. e Relative phosphorescence max. intensity of IPA at 480 nm without or with aptamer with different concentrations of nucleolin. f Average lifetime of IPA–aptamer hybrid assembly with different concentrations of nucleolin. g Time-gated images of IPA–aptamer hybrid assembly after exposure to nucleolin (scale bar: 20 μm). h Increased phosphorescence max. intensity of IPA–aptamer hybrid assembly at 530 nm over reaction time. i Time-gated spectrum of phosphorescence augmentation with accumulated detected signal of IPA–aptamer hybrid assembly after target recognition. j Efficiency of phosphorescence augmentation with accumulated detected signal of IPA–aptamer hybrid assembly after target recognition.