Coating of magnetic nanoparticles affects their interactions with model cell membranes

Design of engineered nanoparticles for biomedical applications by computational modeling

Engineered nanoparticles exhibit superior physicochemical, antibacterial, optical, and sensing properties compared to their bulk counterparts, rendering them attractive for biomedical applications. However, given that nanoparticle properties are sensitive to their nanostructural characteristics and their chemical stability is largely affected by physiological conditions, nanoparticle behavior can be unpredictable in vivo, requiring careful surface modification to ensure biocompatibility, prevent rapid aggregation, and maintain functionality under biological environments. Therefore, understanding the mechanisms of nanoparticle formation and macroscopic behavior in physiological media is essential for the development of structure-property relationships and, their rational design for biomedical applications. Computational simulations provide insight into nanoscale phenomena and nanoparticle dynamics, expediting material discovery and innovation. This review provides an overview of the process design and characterization of metallic and metal oxide nanoparticles with an emphasis on atomistic and mesoscale simulations for their application in bionanomedicine.

Effect of colloidal magnetite (Fe3O4) nanoparticles on the electrical characteristics of the azolectin bilayer in a static inhomogeneous magnetic field

This work is devoted to the study of the combined effects of applied magnetic field and MNPs on the electrical characteristics of bilayer lipid membranes. We present results of the study of electrical parameters of azolectin membranes in a static inhomogeneous magnetic field at the one-sided addition of positively charged quasi-spherical superparamagnetic magnetite nanoparticles with a diameter of about 4 nm. The magnet was located at different distances from the membrane, and the magnetic field attracted the nanoparticles to the membrane surface with different strengths. We observed three pronounced effects that depended on the external magnetic field. Firstly, after addition of nanoparticles in a magnetic field, the conductance of the membranes increased. A smooth increase in conductance was accompanied in some cases by the appearance of current jumps, which can be associated with the formation of through pores with a radius of no more than 1 nm. The conductance increased with increasing magnetic field gradient. Secondly, at zero command voltage, a negative current through the membrane was observed. Although our experiments did not allow us to unambiguously determine which particles create this current, we believe that this current is associated with the penetration of particles through the membrane. This effect intensified with increasing magnetic field gradient. Thirdly, we observed a sharp change in the nonlinear dependence of capacitance on voltage associated both with the change in the surface potential of the azolectin membrane and with the effect of MNP binding to the membrane surface on the apparent membrane capacitance.

Interaction of anionic Fe3O4 nanoparticles with lipid vesicles: a review on deformation and poration under various conditions

This review focuses on the deformation and poration of lipid vesicles caused by the interaction of anionic magnetite nanoparticles (MNPs). Effects of various factors, such as surface charge density, salt and sugar concentrations in buffer, membrane cholesterol content, polymer-grafted phospholipid, and membrane potential have been discussed for the interaction of MNPs with lipid vesicles. To quantify these effects on the vesicles, compactness, fraction of deformation and poration, dynamics of membrane permeation, and kinetics of membrane permeation have been critically evaluated. The review explores the potential advancements as well as future directions of the research field in the biomedical application of MNPs.

PEO-b-PCL/Tween 80/cyclodextrin systems: from bioinspired fabrication to possible nasal administration of ropinirole hydrochloride

In this study, we designed and developed systems composed of poly(ethylene-oxide)-b-poly(ε-caprolactone) block copolymers of different molecular weights and compositions, non-ionic surfactant, and cyclodextrins. The innovation of this study lies in the combination of these diverse biomaterials to create biomimetic and bioinspired drug delivery supramolecular structures. The systems were formed by the thin-film hydration method. Extensive physicochemical and morphological characterization was conducted using differential scanning calorimetry, light scattering techniques, microcalorimetry analysis, high-resolution ultrasound spectroscopy, surface tension measurements, fluorescence spectroscopy, cryogenic transmission electron microscopy images, and in vitro cytotoxicity evaluation. These innovative hybrid nanoparticles were found to be attractive candidates as drug delivery systems with unique properties by encompassing the physicochemical and thermotropic properties of both classes of materials. Subsequently, Ropinirole hydrochloride was used as a model drug for the purpose of this study. These systems showed a high RH content (%), and in vitro diffusion experiments revealed that more than 90% of the loading dose was released under pH and temperature conditions that simulate the conditions of the nasal cavity. Promising drug release performance was observed with all tested formulations, worth further investigation to explore both ex vivo permeation through the nasal mucosa and in vivo performance in an experimental animal model.

Mechanistic insights into interactions between ionizable lipid nanodroplets and biomembranes

Delivery of RNA into cells using lipid nanoparticles (LNPs) has been a significant breakthrough in RNA-based medicine, with clinical applicability expanded through the use of ionizable lipids (ILs). These unique lipids can alter their charge state in response to pH changes, which is crucial for pH-triggered endosomal escape and effective lipid-mediated RNA delivery. In this study, we conducted a comprehensive set of molecular dynamics (MD) simulations to investigate interactions between IL-containing lipid nanodroplets (LNDs) and cell membrane models. Using an atomistic resolution model, we investigated the merging process of LNDs with cell membrane models under neutral conditions relevant to an intercellular environment and acidic pH conditions found in late endosomes. Our observations revealed that at neutral pH, LNDs merged with lipid membranes while preserving the bilayer structure. Under acidic conditions, the LNDs remained attached to the bilayer without fusing into the membranes. Importantly, the presence of ILs did not disrupt the original biomembrane structure during the simulation period. The MD simulations provided valuable atomistic insights into the mechanism of interaction between IL-containing nanodroplets and biomembranes, which could aid the rational design of ILs to develop more efficient LNPs for RNA therapies.

Fabricating Polymer/Surfactant/Cyclodextrin Hybrid Particles for Possible Nose-to-Brain Delivery of Ropinirole Hydrochloride: In Vitro and Ex Vivo Evaluation

Ropinirole is a non-ergolinic dopamine agonist used to manage Parkinson's disease and it is characterized by poor oral bioavailability. This study aimed to design and develop advanced drug delivery systems composed of poloxamer 407, a non-ionic surfactant (Tween 80), and cyclodextrins (methyl-β-CD or hydroxy-propyl-β-CD) for possible brain targeting of ropinirole after nasal administration for the treatment of Parkinson's disease. The hybrid systems were formed by the thin-film hydration method, followed by an extensive physicochemical and morphological characterization. The in vitro cytotoxicity of the systems on HEK293 cell lines was also tested. In vitro release and ex vivo mucosal permeation of ropinirole were assessed using Franz cells at 34 °C and with phosphate buffer solution at pH 5.6 in the donor compartment, simulating the conditions of the nasal cavity. The results indicated that the diffusion-controlled drug release exhibited a progressive increase throughout the experiment, while a proof-of-concept experiment on ex vivo permeation through rabbit nasal mucosa revealed a better performance of the prepared hybrid systems in comparison to ropinirole solution. The encouraging results in drug release and mucosal permeation indicate that these hybrid systems can serve as attractive platforms for effective and targeted nose-to-brain delivery of ropinirole with a possible application in Parkinson's disease. Further ex vivo and in vivo studies to support the results of the present work are ongoing.

Bioinspired Synthesis of Magnetic Nanoparticles Based on Iron Oxides Using Orange Waste and Their Application as Photo-Activated Antibacterial Agents

Magnetic nanoparticles based on iron oxides (MNPs-Fe) have been proposed as photothermal agents (PTAs) within antibacterial photothermal therapy (PTT), aiming to counteract the vast health problem of multidrug-resistant bacterial infections. We present a quick and easy green synthesis (GS) to prepare MNPs-Fe harnessing waste. Orange peel extract (organic compounds) was used as a reducing, capping, and stabilizing agent in the GS, which employed microwave (MW) irradiation to reduce the synthesis time. The produced weight, physical-chemical features and magnetic features of the MNPs-Fe were studied. Moreover, their cytotoxicity was assessed in animal cell line ATCC RAW 264.7, as well as their antibacterial activity against Staphylococcus aureus and Escherichia coli. We found that the 50GS-MNPs-Fe sample (prepared by GS, with 50% v/v of NH₄OH and 50% v/v of orange peel extract) had an excellent mass yield. Its particle size was ~50 nm with the presence of an organic coating (terpenes or aldehydes). We believe that this coating improved the cell viability in extended periods (8 days) of cell culture with concentrations lower than 250 µg·mL^-1, with respect to the MNPs-Fe obtained by CO and single MW, but it did not influence the antibacterial effect. The bacteria inhibition was attributed to the plasmonic of 50GS-MNPs-Fe (photothermal effect) by irradiation with red light (630 nm, 65.5 mW·cm^-2, 30 min). We highlight the superparamagnetism of the 50GS-MNPs-Fe over 60 K in a broader temperature range than the MNPs-Fe obtained by CO (160.09 K) and MW (211.1 K). Therefore, 50GS-MNPs-Fe could be excellent candidates as broad-spectrum PTAs in antibacterial PTT. Furthermore, they might be employed in magnetic hyperthermia, magnetic resonance imaging, oncological treatments, and so on.

Cytocompatibility of pH-sensitive, chitosan-coated Fe3O4 nanoparticles in gynecological cells

Nanoparticles that contact human cells without damaging basic human tissues are becoming more widely used in medicine. Efficient delivery to the intracellular target cell or compartment through the cell membrane must be achieved with minimal cytotoxicity to healthy cells. Fe₃O₄ nanoparticles have been widely used in biomedical research for their magnetic, non-toxic, and biocompatible properties. However, the effects of Fe₃O₄ nanoparticles coated with chitosan (CS) on gynecological cells are unclear. In this study, the Fe₃O₄ nanoparticles were coated with CS to enhance their cytocompatibility and dispersion in water. These CS-Fe₃O₄ nanoparticles were taken up by gynecological cells and did not affect cell viability in vitro. They have greater cytocompatibility in acidic environments than normal Fe₃O₄ nanoparticles and have the potential for drug delivery into gynecological cells.