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Magnetic networks of carbon quantum dots and Ag particles

Wang, Ling, Wang, Yitong, Hu, Yuanyuan, Wang, Guangzhen, Dong, Shuli, Hao, Jingcheng
Journal of colloid and interface science 2019 v.539 pp. 203-213
DNA, bromides, carbon quantum dots, cysteine, electrostatic interactions, fluorescence, ions, ligands, magnetic fields, magnetic separation, moieties, nanosilver, silver, surfactants
Self-assembly exploits a facile non-covalent way to couple structurally different building blocks for creating soft materials with synergetic novel properties and functions. Taking advantage of magneto-properties from magnetic surfactants as well as versatile functional ligand formed by carbon quantum dots with cysteine (cys-CQDs), the magnetic network materials were firstly constructed by using magnetic surfactants and cys-CQDs as self-assembly building blocks. Counterions of Br−, [GdCl3Br]−, [HoCl3Br]− in surfactants could control the morphology of magnetic network structures, and the concentration of magnetic surfactants manoeuvres a versatile scenario of self-assembly behavior. Self-assembly of cys-CQDs and CTAHo brought out a 10-fold increase in magnetic moment of CTAHo. The fluorescent property of carbon quantum dots firstly served as an effective indicator element to dissect the collective effect in self-assembly process. For the sake of capturing the target sequence-specific DNA molecules, in situ growth of Ag nanoparticles (AgNPs) upon the magnetic network structures was realized by synergetically electrostatic and coordinated interaction of carboxyl groups and Ag ions. The magnetic Ag self-assemblies anchored thiol-containing DNA, serving as a magnetic separation booster for the target sequence-specific DNA molecules under an applied magnetic field, which will bring light on designing magneto-functional self-assembly materials according to practical application requirements.