Grafting of quantum dots on covalent organic frameworks via a reverse microemulsion for highly selective and sensitive protein optosensing

A novel reverse microemulsion strategy coupled with surface imprinting technology is developed for the synthesis of CdSe/ZnS quantum dots (QDs)-grafted covalent organic frameworks (COFs) that were used for optosensing protein. COFs are unique in that they are made from lighter elements have tunable skeletons, compared with inorganic porous materials. The functional COFs have become the attractive promising candidates for diversified applications. In this study, a novel thermally and chemically stable three-dimensional crystalline array of QDs grafted on COFs was synthesized, which was performed by Schiff base reactions of 1,3,5-triformylphloroglucinol-P-phenylenediamine (TpPa) and 3-aminopropyltriethoxysilane (APTEs)-modified CdSe/ZnS quantum dots. TpPa was treated as supports to enhance the sensitivity, and APTES modified QDs were employed as tentacle to selectively and sensitively sense the protein-bonding interactions, and further transduce it to the detectable fluorescence signals. The QD-grafted COFs exhibited high thermal stability, repeatability, selective and sensitive optosensing of protein, and the low detection limits was 5.4 x 10(-4) mg/mL. The proposed strategy provides a promising method for the fabrication of QDs-grafted COFs and the great potential of QDs-grafted COFs as a sensing platform for protein detection. (C) 2018 Elsevier B.V. All rights reserved.