Polymer coated gold-ferric oxide superparamagnetic nanoparticles for theranostic applications

Abstract

BackgroundEngineered inorganic nanoparticles (NPs) are essential components in the development of nanotechnologies. For applications in nanomedicine, particles need to be functionalized to ensure a good dispersibility in biological fluids. In many cases however, functionalization is not sufficient: the particles become either coated by a corona of serum proteins or precipitate out of the solvent. We show that by changing the coating of magnetic iron oxide NPs using poly-l-lysine (PLL) polymer the colloidal stability of the dispersion is improved in aqueous solutions including water, phosphate buffered saline (PBS), PBS with 10% fetal bovine serum (FBS) and cell culture medium, and the internalization of the NPs toward living mammalian cells is profoundly affected.MethodsA multifunctional magnetic NP is designed to perform a near-infrared (NIR)-responsive remote control photothermal ablation for the treatment of breast cancer. In contrast to the previously reported studies of gold (Au) magnetic (Fe3O4) core–shell NPs, a Janus-like nanostructure is synthesized with Fe3O4 NPs decorated with Au resulting in an approximate size of 60 nm mean diameter. The surface of trisoctahedral Au–Fe3O4 NPs was coated with a positively charged polymer, PLL to deliver the NPs inside cells. The PLL–Au–Fe3O4 NPs were characterized by transmission electron microscopy (TEM), XRD, FT-IR and dynamic light scattering (DLS). The unique properties of both Au surface plasmon resonance and superparamagnetic moment result in a multimodal platform for use as a nanothermal ablator and also as a magnetic resonance imaging (MRI) contrast agent, respectively. Taking advantage of the photothermal therapy, PLL–Au–Fe3O4 NPs were incubated with BT-474 and MDA-MB-231 breast cancer cells, investigated for the cytotoxicity and intracellular uptake, and remotely triggered by a NIR laser of ~ 808 nm (1 W/cm2 for 10 min).ResultsThe PLL coating increased the colloidal stability and robustness of Au–Fe3O4 NPs (PLL–Au–Fe3O4) in biological media including cell culture medium, PBS and PBS with 10% fetal bovine serum. It is revealed that no significant (< 10%) cytotoxicity was induced by PLL–Au–Fe3O4 NPs itself in BT-474 and MDA-MB-231 cells at concentrations up to 100 μg/ml. Brightfield microscopy, fluorescence microscopy and TEM showed significant uptake of PLL–Au–Fe3O4 NPs by BT-474 and MDA-MB-231 cells. The cells exhibited 40 and 60% inhibition in BT-474 and MDA-MB-231 cell growth, respectively following the internalized NPs were triggered by a photothermal laser using 100 μg/ml PLL–Au–Fe3O4 NPs. The control cells treated with NPs but without laser showed < 10% cell death compared to no laser treatment controlConclusionCombined together, the results demonstrate a new polymer gold superparamagnetic nanostructure that integrates both diagnostics function and photothermal ablation of tumors into a single multimodal nanoplatform exhibiting a significant cancer cell death.Electronic supplementary materialThe online version of this article (10.1186/s12951-018-0405-7)...

Design and Synthesis of Multi-Functional Superparamagnetic Core-Gold Shell Nanoparticles Coated with Chitosan and Folate for Targeted Antitumor Therapy

“…The combination of Au NPs and SPION enables drug accumulation in a specific location in the body by using a magnetic field for effective targeted therapy at the tumor site [ 16 ]. The Au-coated SPION is a robust platform and a suitable agent for improving stability, biocompatibility, and surface interaction [ 17 ]. The chitosan (CS) surface is a natural cationic polysaccharide that exhibits low toxicity, biocompatibility, and hydrophilicity and is subsequently considered for DOX delivery [ 18 ].…”

Synthesis and Properties of Magnetic Self‐Healing Polymers: An Effective Method for Improving Interface Compatibility of Doped Functional Polymers

“…It can be attributed to the diamagnetic organic polymers coated on the surface of the pure Fe 3 O 4 NPs and with the proportion of the organic polymers increasing both in the coated Fe 3 O 4 NPs and magnetic self‐healing polymers, the actual saturation magnetization decreases obviously. The reason has been suggested in many former literature ,,. Though the sharp decrease of the actual saturation magnetization in magnetic self‐healing polymers compared with the pure and coated Fe 3 O 4 NPs, it still remains a certain intensity that do great contribution to the self‐healing of the magnetic self‐healing polymers both internal and external when applied an external magnetic field.…”

“…Thus, synthesizing a kind of nanoparticles with high compatibility is important. There are many former reports which had highlight the importance of interface compatibility between inorganic and organic materials and made great progress in medicine science and biological research, but the application in chemical science such as self‐healing polymers materials was rarely reported before.…”

Theranostics Based on Magnetic Nanoparticles and Polymers: Intelligent Design for Efficient Diagnostics and Therapy

“…Janus particles composed of trisoctahedral magnetite NPs and Au NPs coated with poly-L-lysine yielded a single nanoprobe with increased stability in vivo and efficient photothermal tumor ablation (due to gold) as well as enhanced MRI contrast properties due to the polymer layer (Abedin et al, 2018 ). Each constituent of these multicomponent particles plays an important role in theranostic applications.…”