Clustering of Iron Oxide Nanoparticles with Amphiphilic Invertible Polymer Enhances Uptake and Release of Drugs and MRI Properties

Abstract

A functionalization of iron oxide nanoparticles (NPs) of different diameters by the amphiphilic invertible polymer, (PEG600‐alt‐PTHF650)k (PEG and PTHF stand for poly(ethylene glycol) and poly(tetrahydrofuran), respectively), leads to different NP/polymer architectures for dye/drug uptake and release, as is reported here for the first time. It is demonstrated that 18.6 ± 1.4 and 11.9 ± 0.6 nm NPs are individually coated by this polymer, while 5.9 ± 0.6 nm NPs form nanoparticle clusters (NPCs) which could be isolated by either ultracentrifugation or magnetic separation. This phenomenon is most likely due to the character of the (PEG600‐alt‐PTHF650)k macromolecule with alternating hydrophilic and hydrophobic fragments and its dimensions sufficient to cause NP clustering. Utilizing Rhodamine B base (RBB) and doxorubicin (DOX), the data on uptake upon mixing and further release via inversion into octanol (mimicking the penetration of the cell biomembrane) are presented. The magnetic NPCs display enhanced uptake and release of both RBB and DOX most likely due to the higher retained polymer amount. The NPCs also display exceptional magnetic resonance imaging properties. This and the high uptake/release efficiency of the NPCs combined with easy magnetic separation make them promising for theranostic probes for magnetically targeted drug delivery.

Naturally Derived Melanin Nanoparticle Composites with High Electrical Conductivity and Biodegradability

“…This melanin composite demonstrates hierarchical structures with 1) tightly packed MNPs in a mesoscale cluster ( Figure d), 2) a porous layer formed by continuously connected mesoscale melanin clusters (Figure c), and 3) a PVA‐rich strip at the top of the dried film (Figure b), rather than a simple uniformly dispersed film. Evidently, the MNPs were not dispersed in a uniform fashion but formed coarsely aggregated MNP clusters by depletion attraction forces between MNPs, which support macro‐structures within the continuum. When the MNP clusters were formed, PVA molecules must be drawn back from the MNP surfaces, and thus tightly packed and electrically conductive MNP clusters were effectively formed.…”

In Vitro Studies of Fe3O4‐ZIF‐8 Core–Shell Nanoparticles Designed as Potential Theragnostics

“…Therefore, various coatings have been suggested to enlarge the drug loading capacity of Fe 3 O 4 nanoparticles. These include coating with various polymers, [ 11,12 ] mesoporous silica, [ 13,14 ] or graphene oxide. [ 15 ] Especially, the attempts with the mesoporous silica coating yielded nanoparticles with high drug loading.…”