Improving the Cellular Uptake of Biomimetic Magnetic Nanoparticles

This research was funded by the FUR (Fondo Unico della Ricerca—University of Verona) of M. Perduca. C.J.-L. acknowledges funding from projects CGL2016-76723 from the Ministerio de Economía y Competitividad from Spain and Fondo Europeo de Desarrollo Regional (FEDER) and Programa Operativo FEDER 2014–2020 (A-BIO-376-UGR18) Junta de Andalucia. M.P.C.-J. acknowledges funding from projects PID2019-109294RB-100 from the Ministerio de Ciencia e Innovación from Spain.We are grateful to the “Centro Piattaforme Tecnologiche” of the University of Verona for giving access to DLS equipment. CJL acknowledges. the Unidad Cientıfica de Excelencia UCE PP 2016.05 (U. Granada) and Instituto de Biotecnología. Y.J. wants to acknowledge a FPU2016 grant (ref. FPU16_04580) from the Ministerio de Educación, Ciencia y Deporte y Competitividad (Spain). AS-L is funded by the Spanish Ministry of Science, Innovation and Universities: Formación de Doctores 2018 (ref. PRE2018-0854409). Thanks go to the Scientific Instrumentation Center (CIC) personnel of the University of Granada for technical assistance with the TEM.We also thank Salvatore Calogero Gaglio for his help in preparing Figure S4.Magnetococcus marinus magnetosome-associated protein MamC, expressed as recombinant, has been proven to mediate the formation of novel biomimetic magnetic nanoparticles (BMNPs) that are successful drug nanocarriers for targeted chemotherapy and hyperthermia agents. These BMNPs present several advantages over inorganic magnetic nanoparticles, such as larger sizes that allow the former to have larger magnetic moment per particle, and an isoelectric point at acidic pH values, which allows both the stable functionalization of BMNPs at physiological pH value and the molecule release at acidic (tumor) environments, simply based on electrostatic interactions. However, difficulties for BMNPs cell internalization still hold back the efficiency of these nanoparticles as drug nanocarriers and hyperthermia agents. In the present study we explore the enhanced BMNPs internalization following upon their encapsulation by poly (lactic-co-glycolic) acid (PLGA), a Food and Drug Administration (FDA) approved molecule. Internalization is further optimized by the functionalization of the nanoformulation with the cell-penetrating TAT peptide (TATp). Our results evidence that cells treated with the nanoformulation [TAT-PLGA(BMNPs)] show up to 80% more iron internalized (after 72 h) compared to that of cells treated with BMNPs (40%), without any significant decrease in cell viability. This nanoformulation showing optimal internalization is further characterized. In particular, the present manuscript demonstrates that neither its magnetic properties nor its performance as a hyperthermia agent are significantly altered due to the encapsulation. In vitro experiments demonstrate that, following upon the application of an alternating magnetic field on U87MG cells treated with BMNPs and TAT-PLGA(BMNPs), the cytotoxic effect of BMNPs was not affected by the TAT-PLGA enveloping. Based on that, difficulties shown in previous studies related to poor cell uptake of BMNPs can be overcome by the novel nanoassembly described here.FUR (Fondo Unico della Ricerca-University of Verona)Ministerio de Economia y Competitividad from Spain CGL2016-76723European Commission CGL2016-76723Junta de Andalucia A-BIO-376-UGR18Spanish Government PID2019-109294RB-10

In vitro characterization of adipose stem cells non-enzymatically extracted from the thigh and abdomen

Autologous fat grafting is a surgical technique in which adipose tissue is transferred from one area of the body to another, in order to reconstruct or regenerate damaged or injured tissues. Before reinjection, adipose tissue needs to be purified from blood and cellular debris to avoid inflammation and preserve the graft viability. To perform this purification, different enzymatic and mechanical methods can be used. In this study, we characterized in vitro the product of a closed automatic device based on mechanical disaggregation, named Rigenera\uae, focusing on two sites of adipose tissue harvesting. At first, we optimized the Rigenera\uae operating timing, demonstrating that 60 s of treatment allows a higher cellular yield, in terms of the cell number and growth rate. This result optimizes the mechanical disaggregation and it can increase the clinical efficiency of the final product. When comparing the extracted adipose samples from the thigh and abdomen, our results showed that the thigh provides a higher number of mesenchymal-like cells, with a faster replication rate and a higher ability to form colonies. We can conclude that by collecting adipose tissue from the thigh and treating it with the Rigenera\uae device for 60 s, it is possible to obtain the most efficient product

Nanoparticles exhibiting self-regulating temperature as innovative agents for Magnetic Fluid Hyperthermia

During the last few years, for therapeutic purposes in oncology, considerable attention has been focused on a method called magnetic fluid hyperthermia (MFH) based on local heating of tumor cells. In this paper, an innovative, promising nanomaterial, M48 composed of iron oxide-based phases has been tested. M48 shows self-regulating temperature due to the observable second order magnetic phase transition from ferromagnetic to paramagnetic state. A specific hydrophilic coating based on both citrate ions and glucose molecules allows high biocompatibility of the nanomaterial in biological matrices and its use in vivo. MFH mediator efficiency is demonstrated in vitro and in vivo in breast cancer cells and tumors, confirming excellent features for biomedical application. The temperature increase, up to the Curie temperature, gives rise to a phase transition from ferromagnetic to paramagnetic state, promoting a shortage of the r2 transversal relaxivity that allows a switch in the contrast in Magnetic Resonance Imaging (MRI). Combining this feature with a competitive high transversal (spin-spin) relaxivity, M48 paves the way for a new class of temperature sensitive T2 relaxing contrast agents. Overall, the results obtained in this study prepare for a more affordable and tunable heating mechanism preventing the damages of the surrounding healthy tissues and, at the same time, allowing monitoring of the temperature reached

Improving the Cellular Uptake of Biomimetic Magnetic Nanoparticles

Magnetococcus marinus magnetosome-associated protein MamC, expressed as recombinant, has been proven to mediate the formation of novel biomimetic magnetic nanoparticles (BMNPs) that are successful drug nanocarriers for targeted chemotherapy and hyperthermia agents. These BMNPs present several advantages over inorganic magnetic nanoparticles, such as larger sizes that allow the former to have larger magnetic moment per particle, and an isoelectric point at acidic pH values, which allows both the stable functionalization of BMNPs at physiological pH value and the molecule release at acidic (tumor) environments, simply based on electrostatic interactions. However, difficulties for BMNPs cell internalization still hold back the efficiency of these nano-particles as drug nanocarriers and hyperthermia agents. In the present study we explore the enhanced BMNPs internalization following upon their encapsulation by poly (lac-tic-co-glycolic) acid (PLGA), a Food and Drug Administration (FDA) approved molecule. Inter-nalization is further optimized by the functionalization of the nanoformulation with the cell-penetrating TAT peptide (TATp). Our results evidence that cells treated with the nanofor-mulation [TAT-PLGA(BMNPs)] show up to 80% more iron internalized (after 72 h) compared to that of cells treated with BMNPs (40%), without any significant decrease in cell viability. This nanoformulation showing optimal internalization is further characterized. In particular, the present manuscript demonstrates that neither its magnetic properties nor its performance as a hyperthermia agent are significantly altered due to the encapsulation. In vitro experiments demonstrate that, following upon the application of an alternating magnetic field on U87MG cells treated with BMNPs and TAT-PLGA(BMNPs), the cytotoxic effect of BMNPs was not affected by the TAT-PLGA enveloping. Based on that, difficulties shown in previous studies related to poor cell uptake of BMNPs can be overcome by the novel nanoassembly described here

Biomimetic Magnetic Nanocarriers Drive Choline Kinase Alpha Inhibitor inside Cancer Cells for Combined Chemo-Hyperthermia Therapy

Choline kinase a1 (ChoKa1) has become an excellent antitumor target. Among all the inhibitors synthetized, the new compound Ff35 shows an excellent capacity to inhibit ChoKa1 activity. However, soluble Ff35 is also capable of inhibiting choline uptake, making the inhibitor not selective for ChoKa1. In this study, we designed a new protocol with the aim of disentangling whether the Ff35 biological action is due to the inhibition of the enzyme and/or to the choline uptake. Moreover, we offer an alternative to avoid the inhibition of choline uptake caused by Ff35, since the coupling of Ff35 to novel biomimetic magnetic nanoparticles (BMNPs) allows it to enter the cell through endocytosis without interacting with the choline transporter. This opens the possibility of a clinical use of Ff35. Our results indicate that Ff35-BMNPs nanoassemblies increase the selectivity of Ff35 and have an antiproliferative effect. Also, we demonstrate the effectiveness of the tandem Ff35-BMNPs and hyperthermia.This research was funded by the Ministerio de Economía y Competitividad (CGL2013-46612 and CGL2016-76723 projects), Ramón y Cajal programme (RYC-2014-16901) and the Fondo Europeo de Desarrollo Regional (FEDER). Also, this research was aided by the Andalusian regional government (CTS-236)

Characterization and optimization of nano-structures with hyperthermic properties for biomedical applications.

In the last years, our group focused on magnetic nanoparticles (MNPs), which are able to induce hyperthermia, as potential biomedical tools. Magnetic hyperthermia is a term used to denote the generation of heat by MNPs in response to the application of an external alternating magnetic field. We applied hyperthermia in vitro with different aims and the effects on cells were analyzed by applying viability test and morphological analysis with light and transmission electron microscopy (TEM) techniques. We used superparamagnetic iron oxide nanoparticles (NPs) to induce delipidation in 3T3L1 adipocytes and human adipose-derived adult stem cells. Immediately after hyperthermia, we observed a drastic intracellular lipid loss that persisted for at least 24h in the absence of cell death, damage or dedifferentiation. These results open interesting perspectives for the application of hyperthermia to treat obesity. We applied hyperthermic treatment also to cancer cells, known to be more sensitive to heat shock than healthy cells, in order to induce apoptosis. A glioblastoma cell line (U87MG) was treated with either Zn-SPIONs or biomimetic magnetic NPs (BMNPs). Zn-SPIONs are amphiphilic polymer, dodecyl grafted poly(isobutylene-alt-maleic anhydride) coated zinc-doped iron oxide (Fe3O4) NPs of 15\ub12 nm size, and show a high thermal capacity. BMNPs, synthetized with the protein MamC from magnetotactic bacteria, may act as both drug carriers and hyperthermic agents, being promising tools for the treatment of many types of tumor. BMNPs were also tested in a human hepatocyte carcinoma cell line (HepG2) after functionalizaton with a Choline Kinase inhibitor in order to obtain a nanocarrier potentially suitable for targeted chemotherapy. In fact, Choline Kinase is considered as a biomarker of tumor progression and carcinogenesis, and a target therapy. Therefore, our nanocarriers would allow a local treatment of cancer thus avoiding/reducing possible systemic side effects. The internalization of BMNPs was evaluated using TEM. Taken together, our results prove the efficacy of MNPs in inducing hyperthermia in cultured cells. Although these basic data have been obtained in in vitro models, they suggest the suitability of these NPs as therapeutic tools and encourage further studies for their application in the biomedical field

Testing nanocarriers in vitro: are always cultured cells a reliable reference system?

Different nanocarriers have been tested in vitro in both cultured cells and explanted muscle

Easy formulation of liposomal doxorubicin modified with a bombesin peptide analogue for selective targeting of GRP receptors overexpressed by cancer cells

The article concerns the obtainment of liposomal doxorubicin (Dox) in which liposomes are externally modified with a targeting peptide able to drive the formulation in a selective way on membrane receptors overexpressed in tumors. We developed a kit composed by three different vials: (A) a vial containing a sterile, translucent, red dispersion of the liposomal doxorubicin drug (Doxil®), (B) a vial filled with a lyophilized powder of a modified phospholipid with a reactive function (DSPE-Peg-maleimide), and (C) a vial containing a 1–9 bombesin peptide analogue (Cys-BN-AA1) chemically modified to react in stoichiometric ratio respect to DSPE-Peg-maleimide. The chosen peptide is a stable analogue antagonist of the wild-type 1–9 bombesin peptide; it is very stable in serum; maintains high specificity, with nanomolar affinity, towards gastrin release peptide receptors (GRPRs indicated also as BB2); and is overexpressed in some cancer cells. Results on animal studies clearly indicate that in mice treated with the kit product (i.e., pegylated liposomal Dox modified with the bombesin analogue, Doxil-BN-AA1), tumor growth is reduced, with an improved efficacy respect to mice treated with non-modified pegylated liposomal Dox or with saline solution

Polymer-coated silver-iron nanoparticles as efficient and biodegradable MRI contrast agents

Bimetallic nanoparticles allow new and synergistic properties compared to the monometallic equivalents, often leading to unexpected results. Here we present on silver-iron nanoparticles coated with polyethylene glycol, which exhibit a high transverse relaxivity (316 \ub1 13 mM-1s-1, > 3 times that of the most common clinical benchmark based on iron oxide), excellent colloidal stability and biocompatibility in vivo. Ag-Fe nanoparticles are obtained through a one-step, low-cost laser-assisted synthesis, which makes surface functionalization with the desired biomolecules very easy. Besides, Ag-Fe nanoparticles show biodegradation over a few months, as indicated by incubation in the physiological environment. This is crucial for nanomaterials removal from the living organism and, in fact, in vivo biodistribution studies evidenced that Ag-Fe nanoparticles tend to be cleared from liver over a period in which the benchmark iron oxide contrast agent persisted. Therefore, the Ag-Fe NPs offer positive prospects for the problems of biopersistence, efficient contrast, difficulties of synthesis and surface functionalization usually encountered in nanoparticulate contrast agents

Colloidal polymer-coated Zn-doped iron oxide nanoparticles with high relaxivity and specific absorption rate for efficient magnetic resonance imaging and magnetic hyperthermia

Colloidally stable nanoparticles-based magnetic agents endowed with very high relaxivity and specific absorption rate are extremely desirable for efficient magnetic resonance imaging and magnetic hyperthermia, respectively. Here, we report a water dispersible magnetic agent consisting of zinc-doped superparamagnetic iron oxide nanoparticles (i.e., Zn-SPIONs) of 15 nm size with high saturation magnetization coated with an amphiphilic polymer for effective magnetic resonance imaging and magnetic hyperthermia of glioblastoma cells. These biocompatible polymer-coated Zn-SPIONs had 24 nm hydrodynamic diameter and exhibited high colloidal stability in various aqueous media, very high transverse relaxivity of 471 mM-1 s-1, and specific absorption rate up to 743.8 W g-1, which perform better than most iron oxide nanoparticles reported in the literature, including commercially available agents. Therefore, using these polymer-coated Zn-SPIONs even at low concentrations, T2-weighted magnetic resonance imaging and moderate magnetic hyperthermia of glioblastoma cells under clinically relevant magnetic field were successfully implemented. In addition, the results of this in vitro study suggest the superior potential of Zn-SPIONs as a theranostic nanosystem for brain cancer treatment, simultaneously acting as a contrast agent for magnetic resonance imaging and a heat mediator for localized magnetic hyperthermia