Dendritic maleimide functionalization of core–shell (γ-Fe₂O₃/polymer) nanoparticles for efficient bio-immobilization

Abstract

A new route for the preparation of stable and water-dispersible coreshell g-Fe 2 O 3 /polymer MNPs has been developed in order to ensure a selective and covalent immobilization of biomolecules using maleimide-thiol coupling chemistry. A high maleimide functionalization was achieved by the grafting of dendritic coupling agent via a convergent approach.The integration of chemistry and nanotechnology in the eld of molecular biology has resulted in a new emerging research area, which offers exciting opportunities for discovering new materials, processes, and phenomena.1-4 In the last two decades, tremendous progress has been made in the development of magnetic particles on both synthetic and technological aspects.2-7 Due to the simplicity in their use and their large surface-to-volume ratio, magnetic particles are nowadays the most common solid platform for immobilization and detection of biomolecules.8-12 Among the major advances, important efforts have been dedicated to the development of highly functionalized magnetic nanoparticles (MNPs) for the immobilization of biomolecules. 8,9In this context, one of the major focuses is to design MNPs, which would covalently bind biomolecules without disrupting their biological activity, and concomitantly limit nonspecic adsorption. Nevertheless it is obvious that the amount of covalently immobilized biomolecules is limited by the number of available functional groups at the MNP surface. Therefore, in this work we aimed to ensure a high number of functional groups at the MNP surface by its functionalization with dendritic coupling agent. The efficiency of this approach was demonstrated in our previous results, which showed an increase of the surface functionalization 13-15 together with a dendritic effect on the intrinsic physico-chemical properties of the materials.16 In this study, the maleimide functional group was chosen for its biocompatibility and for its high selectivity towards thiol group of cysteine residue, naturally present or articially introduced in biomolecules. [17][18][19][20] In this context, maleimide functionalization of nanoparticles surfaces is one of the well-studied strategies for bioconjugation of nanoparticles. [21][22][23] Taking into account that the number of cysteine residues naturally present in biomolecules is very scarce (in comparison with other functionalities as amino or carboxyl groups), the maleimide-thiol coupling chemistry enables a degree of control over biomolecular orientation and at the same time requires no additional reagent and generates no byproducts (comparing to the EDC bioconjugate chemistry, for example). The Michael addition of thiol containing biomolecules to maleimide group is typically performed under mild conditions (in aqueous solutions or protic solvent at neutral pH and temperatures from 25 up to 37 C), resulting in the formation of a stable thioether linkage. 20The functionalization of MNPs with dendritic structures can be achieved either by a divergent approach for which the dendritic structure is built step by...

Positive Dendritic Effect on Maleimide Surface Modification of Core-Shell (γ-Fe2O3/Polymer) Nanoparticles for Bio-Immobilization

“…Finally, previously reported G2 was obtained following the general method of growth of PAMAM dendrons followed by Michael type addition of their primary amine to the acrylate 4. [14], [19] Preparation of maleimide modified MNPs…”

“…These are strongly absorbent in the UV-Vis region 520-530 nm, and the absorbance is proportional to the concentration of gold. [22] According to the calibration curve, [14] 1.16 3 10 12 , 1.58 3 10 12 and 1.72 3 10 12 SA-Au NPs are immobilized per mg of respectively g-Fe 2 O 3 /Pol@2-Mal@Biot, g-Fe 2 O 3 /Pol@G1-Mal@-Biot and g-Fe 2 O 3 /Pol@G2-Mal@Biot ( Figure S9). That is to say, 189 pmol, 257 pmol and 280 pmol of streptavidin are immobilized per mg of respectively g-Fe 2 O 3 /Pol@2-Mal@Biot, g-Fe 2 O 3 / Pol@G1-Mal@Biot and g-Fe 2 O 3 /Pol@G2-Mal@Biot MNPs.…”

“…In previous work, we demonstrated that G2 functionalization of MNPs led to efficient specific and selective bioimmobilization by using maleimide-thiol coupling chemistry. [14] Indeed, Streptavidin coated gold nanoparticles were used as nanoscale bio-markers for TEM and UV-Vis analysis of the bioimmobilization efficiency.…”

Polyamidoamine Dendrimers as Crosslinkers for Efficient Electron Transfer between Redox Probes onto Magnetic Nanoparticles

“…Polyamidoamine (PAMAM) dendrimers of different generations are suitable for carboxylate‐modified NPs using carbodiimide chemistry. In previous studies, PAMAM dendrimers were either grafted or built step by step onto iron oxide NPs or other kinds of NPs such as silica or quantum dots …”

“…Polyamidoamine (PAMAM) dendrimers of different generations are suitable for carboxylate-modified NPs using carbodiimide chemistry. In previous studies, PAMAM dendrimers were either grafted [27] or built step by step [28][29][30] onto iron oxide NPs or other kinds of NPs such as silica [31] or quantum dots. [32] This work reports on the functionalization of carboxymodified magnetic NPs with PAMAM dendrimers of different generations derived from the same ethylenediamine (EDA) core.…”