DNA-functionalized dye-loaded carbon dots: ultrabright FRET platform for ratiometric detection of Hg(II) in serum samples and cell microenvironment

摘要

The dual-emission carbon dots (CDs) are used to fabricate an ultra-sensitive and highly selective fluorescence resonance energy transfer (FRET) aptameric-sensor for the quantitation of Hg(II). The designed strategy worked based on hybridization between T-rich ssDNA(S1) immobilized on CDs and AuNPs modified with complementary aptamer (AuNPs-S2) and Rhodamine B (RB) as an extra internal reference. Under optimized experimental conditions, the intensity ratio of I-580/I-668 shows a good linear relationship with the Hg(II) concentration in concentration range of 1.0 x 10(-18) to 50.0 x 10(-5) M with detection limit of 5 x 10(-19) M. The proposed FRET aptasensor showed high selectivity for Hg(II) determination even in the presence of other metal ions with higher concentration as high as 1000 times. Furthermore, the RB-CDs probe was demonstrated to be efficient for MDA-MB 231 cell imaging. The bifunctional signaling probe exhibits impressive simplicity, convenience, and low detection time and the proposed sensor can be applied in biomedicine study, food safety, and environmental protection.