Creation of Linear Carbon Dot Array with Improved Optical Properties through Controlled Covalent Conjugation with DNA

Controlled conjugation of fluorescent carbon dots (CDs) with DNA and subsequent fabrication of the CDs into an array through hybridization mediated self-assembly in the solution phase is reported. Covalent conjugation of CD with DNA and the subsequent array formation change the mobility of the CD-DNA array in gel electrophoresis and HPLC significantly. Interspatial distance in the CD-DNA array is tuned by the DNA sequence length and maintained at ∼8 ± 0.3 nm as revealed by electron microscopy studies. An increase in fluorescence lifetime by ∼2 ns was observed for the CD-DNA array compared to a solitary CD, vis-á-vis better imaging prospects of HEK293 cells by the former. Thus, the array displays improved fluorescence and unhindered cell penetration.