Strategies for the Controlled Covalent Double Functionalization of Graphene Oxide

Abstract

Graphene oxide (GO) is av ersatile platform with unique properties that have found broad applications in the biomedical field. Double functionalization is ak ey aspecti n the designo fmultifunctional GO with combined imaging, targeting, and therapeutic properties. Compared to noncovalent functionalization, covalents trategies lead to GO conjugates with ah igher stability in biological fluids. However, only af ew double covalentf unctionalization approaches have been developed so far.T he complexity of GO makes the derivatization of the oxygenated groups difficult to control. The combination of an ucleophilic epoxide ring opening with the derivatization of the hydroxyl groups through esterification or Williamson reaction was investigated. The conditions were selective and mild, thus preserving the structure of GO. Our strategy of double functionalization holds great potentialf or different applications in which the derivatization of GO with different molecules is needed, especiallyi nt he biomedical field.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.Scheme1.Double-functionalization approach combining the opening of the epoxides and the Williamson reaction (each reaction is showno nly on one functional group for clarity).Scheme2.Double functionalization of GO performedbyc ombining the epoxide opening with esterification on GO-A (each reaction is shownonly on one functional groupf or clarity).

Is carboxylation an efficient method for graphene oxide functionalization?

“…[24][25][26][27] Compared to noncovalent complexation, covalent functionalization enables us to prepare more stable conjugates and minimize the release of molecules adsorbed onto the GO surface, especially for biological applications. Several strategies have been reported to functionalize GO covalently by targeting different functional groups such as carboxylic acids, 28 epoxide rings 29 and hydroxyl groups [30][31][32][33] allowing the development of approaches for double functionalization. 31,32,34 However, the derivatization of the carboxylic acids leads to very low loading efficiency compared to the functionalization of the hydroxyl and epoxide moieties, due to the limited amount of COOH on GO.…”

“…Several strategies have been reported to functionalize GO covalently by targeting different functional groups such as carboxylic acids, 28 epoxide rings 29 and hydroxyl groups [30][31][32][33] allowing the development of approaches for double functionalization. 31,32,34 However, the derivatization of the carboxylic acids leads to very low loading efficiency compared to the functionalization of the hydroxyl and epoxide moieties, due to the limited amount of COOH on GO. 29 Therefore, a higher amount of carboxylic acids would broaden the possibilities for multi-functionalization of GO with a high loading efficiency.…”

Gadolinium-Incorporated Carbon Nanodots for T1-Weighted Magnetic Resonance Imaging

“…All biological experiments were performed using the same batch of material. 55 According to XPS, RCND-DTPA- gram of RCND-DTPA-Gd, we found that there is one Gd atom every 90 C atoms (52.9/0.586).…”

Effect of Alkyl Structures on the Anti‐stacking and Anchoring of Pd/Diamine‐Functionalized Graphene Nanoparticles in Application in Suzuki Reaction

“…Due to the characteristics of GO, it is often regarded as an effective platform for obtaining functionalized or modified graphene based materials. [ 7‐10 ]…”