Facile graft of poly(2-methacryloyloxyethyl phosphorylcholine) onto Fe3O4nanoparticles by ATRP: Synthesis, properties, and biocompatibility

Biocompatibility of magnetic nanoparticles synthesized through green routed with a focus on hematological and histological analysis

The interaction of metal nanoparticles (MNPs) with blood cells and tissues is essential from the perspectives of biocompatibility and the production of novel drug delivery systems. In the present study, biosynthesized-Fe₃O₄ nanoparticles (bio-Fe₃O₄ NPs) were prepared and bio-modified using Daphne mucronata Royle leaf extracts. The physicochemical properties of bio-Fe₃O₄ NPs were determined using UV-Visible spectroscopy, Energy-dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), dynamic light scattering (DLS), and Fourier transform infrared (FT-IR) analyses. According to the SEM analysis, the bio-Fe₃O₄ NPs are spherical-shaped with a size range of 10-30 nm. Antibacterial effects of bio-Fe₃O₄ NPs against Staphylococcus aureus ATCC 43300 and Pseudomonas aeruginosa ATCC 27853 bacteria were measured by minimum inhibition/bactericidal concentrations (MIC and MBC tests). Result showed that the bio-Fe₃O₄ NPs (300 ppm) revealed highest antibacterial effect on S. aureus ATCC 43300. Also, bio-Fe₃O₄ NPs have different cell viability in the human breast cancer cell line (MCF-7) and mouse embryonic fibroblast (MEF). The interaction of bio-Fe₃O₄ NPs with blood cells and the complete blood count (CBC) factor illustrated that the morphology of blood cells and platelet clumping did not influence by nanoparticles. Furthermore, histological analysis of the liver, spleen, and kidney did not show any abnormality upon exposure to 100 mg kg^-1 bio-Fe₃O₄ NPs treated samples. Hence, the biosynthesized Fe₃O₄ NPs are a good candidate for applications in medical fields.

Direct Comparison of Poly(ethylene glycol) and Phosphorylcholine Drug-Loaded Nanoparticles In Vitro and In Vivo

Phosphorylcholine is known to repel the absorption of proteins onto surfaces, which can prevent the formation of a protein corona on the surface of nanoparticles. This can influence the fate of nanoparticles used for drug delivery. This material could therefore serve as an alternative to poly(ethylene glycol) (PEG). Herein, the synthesis of different particles prepared by polymerization-induced self-assembly (PISA) coated with either poly(ethylene glycol) (PEG) or zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and 4-(N-(S-penicillaminylacetyl)amino) phenylarsenonous acid (PENAO) was reported. The anticancer drug 4-(N-(S-penicillaminylacetyl)amino) phenylarsenonous acid (PENAO) was conjugated to the shell-forming block. Interactions of the different coated nanoparticles, which present comparable sizes and size distributions (76-85 nm, PDI = 0.067-0.094), with two-dimensional (2D) and three-dimensional (3D) cultured cells were studied, and their cytotoxicities, cellular uptakes, spheroid penetration, and cell localization profiles were analyzed. While only a minimal difference in behaviour was observed for nanoparticles assessed using in vitro experiment (with PEG-co- PENAO-coated micelles showing slightly higher cytotoxicity and better spheroid penetration and cell localization ability), the effect of the different physicochemical properties between nanoparticles had a more dramatic effect on in vivo biodistribution. After 1 h of injection, the majority of the MPC-co-PENAO-coated nanoparticles were found to accumulate in the liver, making this particle system unfeasible for future biological studies.

Biocompatible zwitterionic copolymer-stabilized magnetite nanoparticles: a simple one-pot synthesis, antifouling properties and biomagnetic separation

A simple one-pot synthesis of biocompatible and antifouling magnetite nanoparticles (Fe₃O₄NPs) was developed. The process involves co-precipitation and in situ coating of zwitterionic copolymer poly[(methacrylic acid)-co-(2-methacryloyloxyethyl phosphorylcholine)] (PMAMPC). The influence of one-step and two-step coating methods on the performance of modified Fe₃O₄NP was investigated. The PMAMPC-Fe₃O₄NP with a narrow particle size distribution obtained from the two-step approach were highly stable in aqueous media within a wide range of pH. The particles exhibited superparamagnetic behavior with high saturation magnetization values so that they could be easily separated from solution by a magnet. Their antifouling characteristics against 2 selected proteins, lysozyme (LYZ) and bovine serum albumin (BSA), as a function of copolymer molecular weight and composition were also evaluated. Moreover, taking advantage of having carboxyl groups in the coated copolymer, the PMAMPC-Fe₃O₄NP were conjugated with a model biomolecular probe, biotin. The biotin-immobilized PMAMPC-Fe₃O₄NP were then tested for their specific capturing of a target molecule, streptavidin. The results have demonstrated the potential of PMAMPC-Fe₃O₄NP prepared by the two-step in situ coating method for probe immobilization and subsequent biomagnetic separation of target molecules. The fact that the developed functionalizable magnetite nanoparticles are biocompatible and antifouling also opens up the possibility of their use in other biomedical-relevant applications.

A simple one-pot synthesis of biocompatible and antifouling magnetite nanoparticles (Fe₃O₄NPs) was developed.

Scalable High-Affinity Stabilization of Magnetic Iron Oxide Nanostructures by a Biocompatible Antifouling Homopolymer

Iron oxide nanostructures have been widely developed for biomedical applications because of their magnetic properties and biocompatibility. In clinical applications, stabilization of these nanostructures against aggregation and nonspecific interactions is typically achieved using weakly anchored polysaccharides, with better-defined and more strongly anchored synthetic polymers not commercially adopted because of their complexity of synthesis and use. Here, we show for the first time stabilization and biocompatibilization of iron oxide nanoparticles by a synthetic homopolymer with strong surface anchoring and a history of clinical use in other applications, poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)]. For the commercially important case of spherical particles, binding of poly(MPC) to iron oxide surfaces and highly effective individualization of magnetite nanoparticles (20 nm) are demonstrated. Next-generation high-aspect-ratio nanowires (both magnetite/maghemite and core-shell iron/iron oxide) are, furthermore, stabilized by poly(MPC) coating, with the nanowire cytotoxicity at large concentrations significantly reduced. The synthesis approach exploited to incorporate functionality into the poly(MPC) chain is demonstrated by random copolymerization with an alkyne-containing monomer for click chemistry. Taking these results together, poly(MPC) homopolymers and random copolymers offer a significant improvement over current iron oxide nanoformulations, combining straightforward synthesis, strong surface anchoring, and well-defined molecular weight.

pH-responsive poly(aspartic acid) hydrogel-coated magnetite nanoparticles for biomedical applications

A novel multifunctional nanosystem formed by magnetite nanoparticles coated with pH-responsive poly(aspartic acid) hydrogel was developed. Magnetite nanoparticles (Fe₃O₄) have been intensively investigated for biomedical applications due to their magnetic properties and dimensions similar to the biostructures. Poly(aspartic acid) is a water-soluble, biodegradable and biocompatible polymer, which features makes it a potential candidate for biomedical applications. The nanoparticles surface modification was carried out by crosslinking polysuccinimide on the magnetite nanoparticles surface and hydrolyzing the succinimide units in mild alkaline medium to obtain the magnetic poly(aspartic acid) hydrogel. The surface modification in each step was confirmed by DRIFTS, TEM and zeta potential measurements. The hydrodynamic diameter of the nanosystems decreases as the pH value decreases. The nanosystems showed high colloidal stability in water and no cytotoxicity was detected, which make these nanosystems suitable for biomedical applications.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Synthesis and in vitro properties of iron oxide nanoparticles grafted with brushed phosphorylcholine and polyethylene glycol

A new and facile strategy for grafting IONPs by phosphonic acic terminated PC brushes has been demonstrated and characterized in vitro.

Controlled synthesis of phosphorylcholine derivatives of poly(serine) and poly(homoserine)

We report methods for the synthesis of polypeptides that are fully functionalized with desirable phosphorylcholine, PC, groups. Because of the inherent challenges in the direct incorporation of the PC group into α-amino acid N-carboxyanhydride (NCA) monomers, we developed a synthetic approach that combined functional NCA polymerization with efficient postpolymerization modification. While poly(L-phosphorylcholine serine) was found to be unstable upon synthesis, we successfully prepared poly(L-phosphorylcholine homoserine) with controlled chain lengths and found these to be water-soluble with disordered chain conformations.

Zwitterionic-coated "stealth" nanoparticles for biomedical applications: recent advances in countering biomolecular corona formation and uptake by the mononuclear phagocyte system

Nanoparticles represent highly promising platforms for the development of imaging and therapeutic agents, including those that can either be detected via more than one imaging technique (multi-modal imaging agents) or used for both diagnosis and therapy (theranostics). A major obstacle to their medical application and translation to the clinic, however, is the fact that many accumulate in the liver and spleen as a result of opsonization and scavenging by the mononuclear phagocyte system. This focused review summarizes recent efforts to develop zwitterionic-coatings to counter this issue and render nanoparticles more biocompatible. Such coatings have been found to greatly reduce the rate and/or extent of non-specific adsorption of proteins and lipids to the nanoparticle surface, thereby inhibiting production of the "biomolecular corona" that is proposed to be a universal feature of nanoparticles within a biological environment. Additionally, in vivo studies have demonstrated that larger-sized nanoparticles with a zwitterionic coating have extended circulatory lifetimes, while those with hydrodynamic diameters of ≤5 nm exhibit small-molecule-like pharmacokinetics, remaining sufficiently small to pass through the fenestrae and slit pores during glomerular filtration within the kidneys, and enabling efficient excretion via the urine. The larger particles represent ideal candidates for use as blood pool imaging agents, whilst the small ones provide a highly promising platform for the future development of theranostics with reduced side effect profiles and superior dose delivery and image contrast capabilities.