Magnetic Colloidal Supraparticles: Design, Fabrication and Biomedical Applications

Abstract

Magnetic nanoparticles (MNPs) bear many intriguing properties such as superparamagnetism, high specific surface area, remarkable colloidal stability and biocompatibility, which evoke great interest and desire of exploration in biomedical applications. For the use in the complicated physiological environment, MNPs are still being developed to have the enhanced performances and down-to-earth practicality. Engineering of MNPs into hierarchical structures is thus proposed to create a new family of magnetic materials, magnetic colloidal supraparticles (MCSPs), which exhibit collective properties and unique nanomaterial characters. From a biomedical point of view, applicability of MCSPs is somewhat more distinctive in contrast to their primary MNPs, because MCSPs are amenable to modulation of secondary structure, promotion of magnetic responsiveness and ease of function design. As a result, MCSPs have been subject to intense researches in recent years, with the aim to develop outstanding composite materials for biomedical applications. In this review, we embark on an overview of foundational topics that detail the design and fabrication of MCSPs by evaporation-induced emulsion and solvothermal techniques, and continue with a guideline for modification of MCSPs with inorganic oxides and organic polymers. Particular focus is then placed on the biomedical applications of modified MCSPs. Many examples illustrate the latest progress in design of MCSP-based microspheres for magnetic resonance imaging, targeted drug delivery, sensing, and harvesting of peptides/proteins. After these detailed accounts, the current challenges and future development of researches and applications are discussed as a conclusion to the review.

Polymer functionalization by luminescent supramolecular gels

“…[16][17][18] The ability of these nanoparticles to disperse must be improved by methods such as surface treatments, which is a barrier to further research and development. [19][20][21] This review focuses on gels (hereafter called supramolecular gels) that can manifest supramolecular functionality through molecular orientation when used as bottom-up nanofillers. We review their use in improving the functionality of transparent polymer materials.…”

Multifunctional Magnetic Gd3+-Based Coordination Polymer Nanoparticles: Combination of Magnetic Resonance and Multispectral Optoacoustic Detections for Tumor-Targeted Imaging in vivo

“…As displayed in Figure S1, Supporting Information, all peaks could be indexed to the cubic structure of Fe 3 As reported, the clustering nanostructure assembled by primary nanoparticles could largely alter the proton relaxation effect. [ 31,32 ] In contrast to a single-domain nanocrystal, the close agglomeration decreases the surface of nanoparticles in contact with water and hence impairs the longitudinal relaxivity ( r 1 ) of clusters, and also, the number and magnetic moment of primary nanoparticles in an assembly are both proportional to transverse relaxivity ( r 2 ). Thus the overall effect of Fe 3 O 4 clusters on r 1 and r 2 cause the increased ratio of r 2 / r 1 and, in turn, yield the high-effi ciency T 2 contrast effect.…”

In Vivo Deep Tissue Fluorescence and Magnetic Imaging Employing Hybrid Nanostructures

“…[13][14][15][16][17][18][19][20] The resulting systems are so-called nanohybrids or hybrid nanostructures (HNS). [21][22][23][24] Recently, great efforts have been made to combine iron oxide NPs (IONPs) with visible/infrared luminescent nanoparticles (LNPs) 25 such as rare earth doped NPs or Quantum Dots (QDs). IONPs are known as contrast agents for magnetic resonance imaging (MRI) 26 and magnetic heating mediators.…”