Bifunctional Nanoparticles with Fluorescence and Magnetism via Surface-Initiated AGET ATRP Mediated by an Iron Catalyst

Abstract

Fluorescent/magnetic nanoparticles are of interest in many applications in biotechnology and nanomedicine for its living detection. In this study, a novel method of surface modification of nanoparticles was first used to modify a fluorescent monomer on the surfaces of magnetic nanoparticles directly. This was achieved via iron(III)-mediated atom-transfer radical polymerization with activators generated by electron transfer (AGET ATRP). Fluorescent monomer 9-(4-vinylbenzyl)-9H-carbazole (VBK) was synthesized and was grafted from magnetic nanoparticles (ferroferric oxide) via AGET ATRP using FeCl(3)·6H(2)O as the catalyst, tris(3,6-dioxaheptyl)amine (TDA-1) as the ligand, and ascorbic acid (AsAc) as the reducing agent. The initiator for ATRP was modified on magnetic nanoparticles with the reported method: ligand exchange with 3-aminopropyltriethoxysilane (APTES) and then esterification with 2-bromoisobutyryl bromide. After polymerization, a well-defined nanocomposite (Fe(3)O(4)@PVBK) was yielded with a magnetic core and a fluorescent shell (PVBK). Subsequently, well-dispersed bifunctional nanoparticles (Fe(3)O(4)@PVBK-b-P(PEGMA)) in water were obtained via consecutive AGET ATRP of hydrophilic monomer poly(ethylene glycol) methyl ether methacrylate (PEGMA). The chemical composition of the magnetic nanoparticles' surface at different surface modification stages was investigated with Fourier transform infrared (FT-IR) spectra. The magnetic and fluorescent properties were validated with a vibrating sample magnetometer (VSM) and a fluorophotometer. The Fe(3)O(4)@PVBK-b-P(PEGMA) nanoparticles showed an effective imaging ability in enhancing the negative contrast in magnetic resonance imaging (MRI).

PNIPAM grafted surfaces through ATRP and RAFT polymerization: Chemistry and bioadhesion

“…Iron is also the most abundant metal on earth making it relatively cheap; these characteristics have initiated a lot of research and interest in Fe catalyzed organic chemistry, including ATRP, in line with the perspectives of "green chemistry" [66,67]. The choice of the ligand is a complex question; it depends on the nature of the polymer and the catalyst used [68]: for example, pentamethyldiethylenetriamine (PMDETA) can be used in combination with Cu [69], and tris(3,6-dioxaheptyl) amine (TDA) with Fe [70]. Furthermore, the activators regenerated by electron transfer (ARGET) ATRP, developed by Matyjaszewski et al diminish the amount of catalyst needed (< 50 ppm) [71,72].…”

Surface-initiated controlled radical polymerizations from silica nanoparticles, gold nanocrystals, and bionanoparticles

“…The grafting density of the immobilized initiator is usually higher than the density of anchored CTAs and attached alkoxyamines, owing to the smaller steric hindrance of ATRP initiators during the attachment in comparison with RAFT agents and alkoxyamines. 41,42,44,[94][95][96][97][98][99][100] Further ATRP variants, especially reverse ATRP, Activator Generated by Electron Transfer (AGET) ATRP, Activator ReGenerated by Electron Transfer (ARGET) ATRP, and electrochemically mediated ATRP (e-ATRP) have also been successfully utilized to grow polymers from the surfaces of hydroxyapatite, 101 silicon, 102,103 gold, 104 quantum dots, 105 chitosan, 106 silica nanoparticles, [107][108][109] cellulose, 110 iron oxide, 111 and carbon nanotubes. 112 In this review, we mainly focus on the fundamental surface-initiated ATRP from nanoparticles.…”

Hydrophilic Silica/Copolymer Nanoparticles and Protein-Resistance Coatings

“…In the recent research, the significant hydrophiphilic block copolymers are mainly used poly (poly (ethylene glycol) methyl ether methacrylate, P (PEGMA), or poly (poly (ethylene glycol) methacrylate, P(PEG), as the hydrophilic block [4]- [7]. Actually, both P(PEGMA) and P(PEG) consist of a linear methacrylate backbone reactive functional group with a side chain of poly(ethylene glycol) (PEG), which could generate a wealth of new polymeric materials by employing the recently developed living radical polymerization techniques of reversible addition fragmentation chain transfer (RAFT) [8] [9] and atom transfer radical polymerization (ATRP) [10]- [12]. In order to achieve the polymer films with adjusted properties by varying the monomer composition based on PEGMA monomer, well-defined block copolymers are synthesized, such as P(PEGMA)-b-poly(2,5-dibromo 3-vinylthiophene) by RAFT for uniform cross-linked nanoparticles [8], poly (glycidyl methacrylate-co-poly (ethylene glycol) methyl ether methacrylate) nanoparticles by ATRP [12].…”