Click chemical assembly and validation of bio-functionalized superparamagnetic hybrid microspheres

Abstract

Surface derivatized magnetic nanoparticles have been commonly used for magnetic separation. Facile mechanisms are needed to be developed for the design of bio-functionalized magnetic hybrid materials, where the surfaces can be regenerated for the re-use of the developed platforms. Superparamagnetic iron oxide nanoparticles with a diameter below 10 nm were synthesized via a novel microwave-assisted hydrothermal method in the presence of citrate ions, which allowed to obtain uniform and negatively charged nanoparticles. These were then coupled with Poly-l-lysine (PLL), forming micrometersized self-assembled spherical entities. Cross-linking the PLL within these microspheres with glutaraldehyde stabilized them chemically and mechanically. The active bio-functionality was introduced by a protein grafting methodology, using m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester (SMBS). The Moringa oleifera Coagulant Protein (MOCP) from a seed extract was employed for its characteristic coagulation activity. The performance of the MOCP functionalized microspheres was evaluated as a function of turbidity removal of problematic colloidal clay from water via magnetic separation, resulting in over 80% of activity within 15 min. Surface of these hybrid materials can be regenerated by treatment with alcohol, allowing their easy magnetic separation and re-use. The rapid and strong response with tunable magnetic property makes these hybrid microspheres a powerful tool for many potential applications, due to the general applicability of the developed methodology.

Magnetoresponsive fluorescent core–shell nanoclusters for biomedical applications

“…Asymmetric and symmetric stretching of the carboxyl groups underwent signicant shis between the unbonded (1580 and 1406 cm −1 ) and bonded (1640 and 1380 cm −1 ) states. 20,34 The bands between 1100 and 1200 cm −1 are ascribed to C-O (Cit and Lys) and C-N (Lys) stretching vibrations. C-H and N-H stretching vibrations can be matched with the weak bands at z2900 cm −1 .…”

“…The self-assembly of SPION nanoclusters (SP-NCs) is one of the promising routes for their enhanced functionality for biomedical applications. [15][16][17] To obtain these SP-NCs, it is usually required to follow multiplestep processes, including embedding in micelles, 18 polymeric matrices or shells, 19,20 liposomes, 21 and hydrogels, 16 among others. These approaches will unavoidably lead to a reduced unit magnetization due to the presence of a considerable amount of organic content, to stabilize the clusters.…”

XFCT-MRI hybrid multimodal contrast agents for complementary imaging

“…Ru NPs displayed hexagonal close-packed (hcp) crystal phase, 31,32 while the face-centered cubic (fcc) crystal lattice of SPIONs was confirmed by the observed diffraction rings/peaks of magnetite (or maghemite). [33][34][35][36][37] The absence of other diffractions permitted to exclude the existence of other impurity phases (e.g., hematite), which would negatively affect the overall magnetization and relaxivity. Ru-SPIONs exhibited the same crystal phases of the constituents, as the SPION phase and structure are not influenced by the heterogeneous nucleation of Ru NPs.…”

Effect of manganese substitution of ferrite nanoparticles on particle grain structure

“…[38][39][40] In this study, the tting was done using SPt, a MATLAB based program that was developed by GM Saladino. 41,42 The temperature was set to 300 K and the bulk saturation magnetization was set to 446 kA m À1 . 43 It should be noted that this model assumes non-interacting particles.…”