Supramolecular Reassembly of Self‐Exfoliated Ionic Covalent Organic Nanosheets for Label‐Free Detection of Double‐Stranded DNA

Abstract

Ionic covalent organic nanosheets (iCONs), a member of the two-dimensional (2D) nanomaterials family, offer a unique functional platform for a wide range of applications. Herein, we explore the potential of an ethidium bromide (EB)-based covalent organic framework (EB-TFP) that self-exfoliates in water resulting in 2D ionic covalent organic nanosheets (EB-TFP-iCONs) for the selective detection of double-stranded DNA (dsDNA). In an aqueous medium, the self-exfoliated EB-TFP-iCONs reassemble in the presence of dsDNA resulting in hybrid EB-TFP-iCONs-DNA crystalline nanosheets with enhanced fluorescence at 600 nm. Detailed steady-state and time-resolved emission studies revealed that the reassembly phenomenon was highly selective for dsDNA when compared to single-stranded DNA (ssDNA), which allowed us to use the EB-TFP-iCONs as a 2D fluorescent platform for the label-free detection of complementary DNA strands.

Table-salt enabled interface-confined synthesis of covalent organic framework (COF) nanosheets

“…16 To take full advantage of the nanoporosity and twodimensional (2D) structure of COFs, it is oen required to use them in the form of thin COF nanosheets (CONs). 11,17,18 CONs with a few nanometers in thickness not only offer more active sites, but also improve mass transfer efficiency. These features signicantly promote the performances of the devices assembled from CONs for applications such as sensing, 19,20 ion conductivity, 11 and separation.…”

Supramolecular Surface Charge Regulation in Ionic Covalent Organic Nanosheets: Reversible Exfoliation and Controlled Bacterial Growth

“…The presence of a large number of surface charges in 2D iCOF materials helps self‐exfoliation in water because of strong charge repulsion and generates a few‐layered thin iCONs . In the case of PI‐TFP‐iCOF , the existence of pendant quaternary ammonium groups and the presence of the quaternary nitrogen center in the framework induce substantial interlayer repulsion.…”

Tailoring Covalent Organic Frameworks To Capture Water Contaminants

“…In addition to uniform designable pore surfaces, COFs feature high surface areas, low densities, and high thermal and chemical stability. Therefore, they have been explored for a wide range of applications, such as gas storage and separation, catalysis, optoelectronics, sensing, and drug delivery . For a comprehensive overview of COFs, the reader is referred to a recent review by Lohse and Bein …”

“…Therefore, by carefulm olecular design and selection,C OFs with tailor-madep ores can be obtained. In addition to uniform designable pore surfaces, COFs feature high surface areas, low densities, and high thermal and chemicals tability.T herefore, they have been exploredf or a wide range of applications, [6] such as gas storage [7][8][9][10] and separation, [11,12] catalysis, [13][14][15][16][17][18][19] optoelectronics, [20][21][22][23] sensing, [24][25][26][27] and drug delivery. [28][29][30] For ac omprehensive overview of COFs, the reader is referredt oarecent review by Lohse and Bein.…”