Green synthesis as a simple and rapid route to protein modified magnetic nanoparticles for use in the development of a fluorometric molecularly imprinted polymer-based assay for detection of myoglobin To cite this article: Mark V Sullivan et al 2021 Nanotechnology 32 095502 View the article online for updates and enhancements.

Novel hierarchically ordered porous magnetic nanocomposites with interconnecting macroporous windows and meso-microporous walls containing well dispersed magnetic nanoparticles have been fabricated and used as a support to immobilise lipase for the efficient hydrolysis of ester.

Superparamagnetic iron oxide nanoparticles (SPIONs) and core-shell type nanoparticles, consisting of SPIONs coated with mesoporous silica and/or lipid, were synthesised and tested for their potential theranostic applications in drug delivery, magnetic hyperthermia and as a contrast agent. Transmission Electron Microscopy (TEM) confirmed the size of bare and coated SPIONs was in the range of 5–20 nm and 100–200 nm respectively. The superparamagnetic nature of all the prepared nanomaterials as indicated by Vibrating Sample Magnetometry (VSM) and their heating properties under an AC field confirm their potential for hyperthermia applications. Scanning Column Magnetometry (SCM) data showed that extrusion of bare-SPION (b-SPION) dispersions through a 100 nm polycarbonate membrane significantly improved the dispersion stability of the sample. No sedimentation was apparent after 18 h compared to a pre-extrusion estimate of 43% settled at the bottom of the tube over the same time. Lipid coating also enhanced dispersion stability. Transversal relaxation time (T2) measurements for the nanoparticles, using a bench-top relaxometer, displayed a significantly lower value of 46 ms, with a narrow relaxation time distribution, for lipid silica coated SPIONs (Lip-SiSPIONs) as compared to that of 1316 ms for the b-SPIONs. Entrapment efficiency of the anticancer drug, Doxorubicin (DOX) for Lip-SPIONs was observed to be 35% which increased to 58% for Lip-SiSPIONs. Moreover, initial in-vitro cytotoxicity studies against human breast adenocarcinoma, MCF-7 cells showed that % cell viability increased from 57% for bSPIONs to 82% for Lip-SPIONs and to 87% for Lip-SiSPIONs. This suggests that silica and lipid coatings improve the biocompatibility of bSPIONs significantly and enhance the suitability of these particles as drug carriers. Hence, the magnetic nanomaterials prepared in this work have potential theranostic properties as a drug carrier for hyperthermia cancer therapy and also offer enhancement of contrast agent efficacy and a route to a significant increase in dispersion stability.

Ultrastable superparamagnetic core-shell nanoparticles of average diameter 80 nm have been fabricated via a simple one-pot method involving superparamagnetic iron oxide nanoparticles (SPIONs) core (y50 nm in diameter) and lipid bilayer shell by high energy ultrasonication. The surface charges (zeta potentials) were measured to be between 215 mV and + 16 mV depending on the batch composition. Anticancer drug mitomycin C (MMC) was loaded into four different samples of variable surface charges in aqueous solution (pH = 6.8) and released in PBS buffer (pH = 7.2) at room temperature. The kinetics of drug loading and releasing data indicated that the stable lipid bilayer coated SPIONs (LBCSPIONs) of nearly neutral surface exhibited the highest loading (10.9 mg of MMC/mg of materials), whereas uncoated or partially coated SPIONs of positive zeta potential exhibited the lowest loading (2.8 and 3.5 mg MMC/mg of materials, respectively). The release behavior of MMC was observed to be highest (5.8 mg MMC/mg of materials) from materials of negative zeta potential compared to materials of near neutral surfaces (3.68 mg MMC/mg of materials). The plausible mechanism of MMC loading and releasing behavior has been explained based on the electrostatic interaction and diffusion through the lipid bilayers. To ensure biocompatibility, the interaction of the prepared SPIONs with human cervical cancer cell line (HeLa) was also investigated using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and ROS (reactive oxygen species) production assay and the results confirmed the supercompatibility of LBCSPIONs.