Deciphering intracellular events triggered by mild magnetic hyperthermia in vitro and in vivo

Phage-Templated Synthesis of Targeted Photoactive 1D-Thiophene Nanoparticles

Thiophene-based nanoparticles (TNPs) are promising therapeutic and imaging agents. Here, using an innovative phage-templated synthesis, a strategy able to bypass the current limitations of TNPs in nanomedicine applications is proposed. The phage capsid is decorated with oligothiophene derivatives, transforming the virus in a 1D-thiophene nanoparticle (1D-TNP). A precise control of the shape/size of the nanoparticles is obtained exploiting the well-defined morphology of a refactored filamentous M13 phage, engineered by phage display to selectively recognize the Epidermal Growth Factor Receptor (EGFR). The tropism of the phage is maintained also after the bioconjugation of the thiophene molecules on its capsid. Moreover, the 1D-TNP proved highly fluorescent and photoactive, generating reactive oxygen species through both type I and type II mechanisms. The phototheranostic properties of this platform are investigated on biosystems presenting increasing complexity levels, from in vitro cancer cells in 2D and 3D architectures, to the in vivo tissue-like model organism Hydra vulgaris. The phage-templated 1D-TNP showed photocytotoxicity at picomolar concentrations, and the ability to deeply penetrate 3D spheroids and Hydra tissues. Collectively the results indicate that phage-templated synthesis of organic nanoparticles represents a general strategy, exploitable in many diagnostic and therapeutic fields based on targeted imaging and light mediated cell ablation.

Membrane-localized magnetic hyperthermia promotes intracellular delivery of cell-impermeant probes

In this work, we report the disruptive use of membrane-localized magnetic hyperthermia to promote the internalization of cell-impermeant probes. Under an alternating magnetic field, magnetic nanoparticles (MNPs) immobilized on the cell membrane via bioorthogonal click chemistry act as nanoheaters and lead to the thermal disruption of the plasma membrane, which can be used for internalization of different types of molecules, such as small fluorescent probes and nucleic acids. Noteworthily, no cell death, oxidative stress and alterations of the cell cycle are detected after the thermal stimulus, although cells are able to sense and respond to the thermal stimulus through the expression of different types of heat shock proteins (HSPs). Finally, we demonstrate the utility of this approach for the transfection of cells with a small interference RNA (siRNA), revealing a similar efficacy to a standard transfection method based on the use of cationic lipid-based reagents (such as Lipofectamine), but with lower cell toxicity. These results open the possibility of developing new procedures for "opening and closing" cellular membranes with minimal disturbance of cellular integrity. This on-demand modification of cell membrane permeability could allow the direct intracellular delivery of biologically relevant (bio)molecules, drugs and nanomaterials, thus overcoming traditional endocytosis pathways and avoiding endosomal entrapment.

Interface Engineering of Water-Dispersible Near-Infrared-Emitting CuInZnS/ZnSe/ZnS Quantum Dots

We report the synthesis of near-infrared (IR)-emitting core/shell/shell quantum dots of CuInZnS/ZnSe/ZnS and their phase transfer to water. The intermediate ZnSe shell was added to inhibit the migration of ions from the standard ZnS shell into the emitting core, which often leads to a blue shift in the emission profile. By engineering the interface between the core and terminal shell layer, the optical properties can be controlled, and emission was maintained in the near-IR region, making the materials attractive for biological applications. In addition, the hydrodynamic diameter of the particle was controlled using amphiphilic polymers.

An Integrated Multilevel Approach Unveils Complex Seed-Nanoparticle Interactions and Their Implications for Seed Priming

Nanotechnology has the potential to revolutionize agriculture with the introduction of engineered nanomaterials. However, their use is hindered by high cost, marginal knowledge of their interactions with plants, and unpredictable effects related to massive use in crop cultivation. Nanopriming is an innovative seed priming technology able to match economic, agronomic, and environmental needs in agriculture. The present study was focused on unveiling, by a multilevel integrated approach, undisclosed aspects of seed priming mediated by iron oxide magnetic nanoparticles in pepper seeds (Capsicum annuum), one of the most economically important crops worldwide. Inductively coupled plasma atomic emission mass spectrometry and scanning electron microscopy were used to quantify the MNP uptake and assess seed surface changes. Magnetic resonance imaging mapped the distribution of MNPs prevalently in the seed coat. The application of MNPs significantly enhanced the root and vegetative growth of pepper plants, whereas seed priming with equivalent Fe concentrations supplied as FeCl3 did not yield these positive effects. Finally, global gene expression by RNA-sequencing identified more than 2,200 differentially expressed genes, most of them involved in plant developmental processes and defense mechanisms. Collectively, these data provide evidence on the link between structural seed changes and an extensive transcriptional reprogramming, which boosts the plant growth and primes the embryo to cope with environmental challenges that might occur during the subsequent developmental and growth stages.

Improving the Efficacy of Magnetic Nanoparticle-Mediated Hyperthermia Using Trapezoidal Pulsed Electromagnetic Fields as an In Vitro Anticancer Treatment in Melanoma and Glioblastoma Multiforme Cell Lines

Magnetic hyperthermia (MHT) is an oncological therapy that uses magnetic nanoparticles (MNPs) to generate localized heat under a low-frequency alternating magnetic field (AMF). Recently, trapezoidal pulsed alternating magnetic fields (TPAMFs) have proven their efficacy in enhancing the efficiency of heating in MHT as compared to the sinusoidal one. Our study aims to compare the TPAMF waveform's killing effect against the sinusoidal waveform in B16F10 and CT2A cell lines to determine more efficient waveforms in causing cell death. For that purpose, we used MNPs and different AMF waveforms: trapezoidal (TP), almost-square (TS), triangular (TR), and sinusoidal signal (SN). MNPs at 1 and 4 mg/mL did not affect cell viability during treatment. The exposition of B16F10 and CT2A cells to only AMF showed nonsignificant mortality. Hence, the synergetic effect of the AMF and MNPs causes the observed cell death. Among the explored cases, the nonharmonic signals demonstrated better efficacy than the SN one as an MHT treatment. This study has revealed that the application of TP, TS, or TR waveforms is more efficient and has considerable capability to increase cancer cell death compared to the traditional sinusoidal treatment. Overall, we can conclude that the application of nonharmonic signals enhances MHT treatment efficiency against tumor cells.

A Novel Patient-Personalized Nanovector Based on Homotypic Recognition and Magnetic Hyperthermia for an Efficient Treatment of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the deadliest brain tumor, characterized by an extreme genotypic and phenotypic variability, besides a high infiltrative nature in healthy tissues. Apart from very invasive surgical procedures, to date, there are no effective treatments, and life expectancy is very limited. In this work, an innovative therapeutic approach based on lipid-based magnetic nanovectors is proposed, owning a dual therapeutic function: chemotherapy, thanks to an antineoplastic drug (regorafenib) loaded in the core, and localized magnetic hyperthermia, thanks to the presence of iron oxide nanoparticles, remotely activated by an alternating magnetic field. The drug is selected based on ad hoc patient-specific screenings; moreover, the nanovector is decorated with cell membranes derived from patients' cells, aiming at increasing homotypic and personalized targeting. It is demonstrated that this functionalization not only enhances the selectivity of the nanovectors toward patient-derived GBM cells, but also their blood-brain barrier in vitro crossing ability. The localized magnetic hyperthermia induces both thermal and oxidative intracellular stress that lead to lysosomal membrane permeabilization and to the release of proteolytic enzymes into the cytosol. Collected results show that hyperthermia and chemotherapy work in synergy to reduce GBM cell invasion properties, to induce intracellular damage and, eventually, to prompt cellular death.

Photonic and magnetic materials for on-demand local drug delivery

Nanomedicine has been considered a promising tool for biomedical research and clinical practice in the 21st century because of the great impact nanomaterials could have on human health. The generation of new smart nanomaterials, which enable time- and space-controlled drug delivery, improve the limitations of conventional treatments, such as non-specific targeting, poor biodistribution and permeability. These smart nanomaterials can respond to internal biological stimuli (pH, enzyme expression and redox potential) and/or external stimuli (such as temperature, ultrasound, magnetic field and light) to further the precision of therapies. To this end, photonic and magnetic nanoparticles, such as gold, silver and iron oxide, have been used to increase sensitivity and responsiveness to external stimuli. In this review, we aim to report the main and most recent systems that involve photonic or magnetic nanomaterials for external stimulus-responsive drug release. The uniqueness of this review lies in highlighting the versatility of integrating these materials within different carriers. This leads to enhanced performance in terms of in vitro and in vivo efficacy, stability and toxicity. We also point out the current regulatory challenges for the translation of these systems from the bench to the bedside, as well as the yet unresolved matter regarding the standardization of these materials.

Optical Control of Tissue Regeneration through Photostimulation of Organic Semiconducting Nanoparticles

Next generation bioengineering strives to identify crucial cues that trigger regeneration of damaged tissues, and to control the cells that execute these programs with biomaterials and devices. Molecular and biophysical mechanisms driving embryogenesis may inspire novel tools to reactivate developmental programs in situ. Here nanoparticles based on conjugated polymers are employed for optical control of regenerating tissues by using an animal with unlimited regenerative potential, the polyp Hydra, as in vivo model, and human keratinocytes as an in vitro model to investigate skin repair. By integrating animal, cellular, molecular, and biochemical approaches, nanoparticles based on poly-3-hexylthiophene (P3HT) are shown able to enhance regeneration kinetics, stem cell proliferation, and biomolecule oxidation levels. Opposite outputs are obtained with PCPDTBT-NPs (Poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b'] dithiophene)-alt-4,7(2,1,3-benzothiadiazole)], causing a beneficial effect on Hydra regeneration but not on the migratory capability of keratinocytes. These results suggest that the artificial modulation of the redox potential in injured tissues may represent a powerful modality to control their regenerative potential. Importantly, the possibility to fine-tuning materials' photocatalytic efficiency may enable a biphasic modulation over a wide dynamic range, which can be exploited to augment the tissue regenerative capacity or inhibit the unlimited potential of cancerous cells in pathological contexts.

Pathological impact and medical applications of electromagnetic field on melanoma: A focused review

Electromagnetic Field (EMF) influences melanoma in various ways. EMF can be classified into extremely low-frequency electromagnetic field, low-frequency magnetic field, static moderate magnetic field, strong electromagnetic field, alternating magnetic field, and magnetic nanoparticles. Each type of EMF influences melanoma development differently, and the detailed influence of each specific type of EMF on melanoma is reviewed. Furthermore, EMF influences melanoma cell polarity and hence affects drug uptake. In this review, the impacts of EMF on the effectiveness of drugs used to treat melanoma are listed according to drug types, with detailed effects according to the types of EMF and specific melanoma cell lines. EMF also impacts clinical therapies of melanoma, including localized magnetic hyperthermia, focalized thermotherapy, proton radiation treatment, nanostructure heating magnetic hyperthermia, radiation therapy, Polycaprolactone-Fe₃O₄ fiber mat-based bandage, and optune therapy. Above all, EMF has huge potential in melanoma treatment.

The Intracellular Number of Magnetic Nanoparticles Modulates the Apoptotic Death Pathway after Magnetic Hyperthermia Treatment

Magnetic hyperthermia is a cancer treatment based on the exposure of magnetic nanoparticles to an alternating magnetic field in order to generate local heat. In this work, 3D cell culture models were prepared to observe the effect that a different number of internalized particles had on the mechanisms of cell death triggered upon the magnetic hyperthermia treatment. Macrophages were selected by their high capacity to uptake nanoparticles. Intracellular nanoparticle concentrations up to 7.5 pg Fe/cell were measured both by elemental analysis and magnetic characterization techniques. Cell viability after the magnetic hyperthermia treatment was decreased to <25% for intracellular iron contents above 1 pg per cell. Theoretical calculations of the intracellular thermal effects that occurred during the alternating magnetic field application indicated a very low increase in the global cell temperature. Different apoptotic routes were triggered depending on the number of internalized particles. At low intracellular magnetic nanoparticle amounts (below 1 pg Fe/cell), the intrinsic route was the main mechanism to induce apoptosis, as observed by the high Bax/Bcl-2 mRNA ratio and low caspase-8 activity. In contrast, at higher concentrations of internalized magnetic nanoparticles (1-7.5 pg Fe/cell), the extrinsic route was observed through the increased activity of caspase-8. Nevertheless, both mechanisms may coexist at intermediate iron concentrations. Knowledge on the different mechanisms of cell death triggered after the magnetic hyperthermia treatment is fundamental to understand the biological events activated by this procedure and their role in its effectiveness.

Gold Nanorods and Nanoprisms Mediate Different Photothermal Cell Death Mechanisms In Vitro and In Vivo

Photothermal therapy (PTT) is an efficient method of inducing localized hyperthermia and can be achieved using gold nanoparticles as photothermal agents. However, there are many hurdles to get over before this therapy can safely reach the clinics, including nanoparticles' optimal shape and the accurate prediction of cellular responses. Here, we describe the synthesis of gold nanorods and nanoprisms with similar surface plasmon resonances in the near-infrared (NIR) and comparable photothermal conversion efficiencies and characterize the response to NIR irradiation in two biological systems, melanoma cells and the small invertebrate Hydra vulgaris. By integrating animal, cellular, and molecular biology approaches, we show a diverse outcome of nanorods and nanoprisms on the two systems, sustained by the elicitation of different pathways, from necrosis to programmed cell death mechanisms (apoptosis and necroptosis). The comparative multilevel analysis shows great accuracy of in vivo invertebrate models to predict overall responses to photothermal challenging and superior photothermal performance of nanoprisms. Understanding the molecular pathways of these responses may help develop optimized nanoheaters that, safe by design, may improve PTT efficacy for clinical purposes.

Confining Iron Oxide Nanocubes inside Submicrometric Cavities as a Key Strategy To Preserve Magnetic Heat Losses in an Intracellular Environment

The design of magnetic nanostructures whose magnetic heating efficiency remains unaffected at the tumor site is a fundamental requirement to further advance magnetic hyperthermia in the clinic. This work demonstrates that the confinement of magnetic nanoparticles (NPs) into a sub-micrometer cavity is a key strategy to enable a certain degree of nanoparticle motion and minimize aggregation effects, consequently preserving the magnetic heat loss of iron oxide nanocubes (IONCs) under different conditions, including intracellular environments. We fabricated magnetic layer-by-layer (LbL) self-assembled polyelectrolyte sub-micrometer capsules using three different approaches, and we studied their heating efficiency as obtained in aqueous dispersions and after internalization by tumor cells. First, IONCs were added to the hollow cavities of LbL submicrocapsules, allowing the IONCs to move to a certain extent in the capsule cavities. Second, IONCs were coencapsulated into solid calcium carbonate cores coated with LbL polymer shells. Third, IONCs were incorporated within the polymer layers of the LbL capsule walls. In aqueous solution, higher specific absorption rate (SAR) values were related to those of free IONCs, while lower SAR values were recorded for capsule/core assemblies. However, after uptake by cancer cell lines (SKOV-3 cells), the SAR values of the free IONCs were significantly lower than those observed for capsule/core assemblies, especially after prolonged incubation periods (24 and 48 h). These results show that IONCs packed into submicrocavities preserve the magnetic losses, as the SAR values remained almost invariable. Conversely, free IONCs without the protective capsule shell agglomerated and their magnetic losses were strongly reduced. Indeed, IONC-loaded capsules and free IONCs reside inside endosomal and lysosomal compartments after cellular uptake and show strongly reduced magnetic losses due to the immobilization and aggregation in centrosymmetrical structures in the intracellular vesicles. The confinement of IONCs into sub-micrometer cavities is a key strategy to provide a sustained and predictable heating dose inside biological matrices.

In Vivo Biotransformations of Indium Phosphide Quantum Dots Revealed by X-Ray Microspectroscopy

Many attempts have been made to synthesize cadmium-free quantum dots (QDs), using nontoxic materials, while preserving their unique optical properties. Despite impressive advances, gaps in knowledge of their intracellular fate, persistence, and excretion from the targeted cell or organism still exist, precluding clinical applications. In this study, we used a simple model organism (Hydra vulgaris) presenting a tissue grade of organization to determine the biodistribution of indium phosphide (InP)-based QDs by X-ray fluorescence imaging. By complementing elemental imaging with In L-edge X-ray absorption near edge structure, unique information on in situ chemical speciation was obtained. Unexpectedly, spectral profiles indicated the appearance of In-O species within the first hour post-treatment, suggesting a fast degradation of the InP QD core in vivo, induced mainly by carboxylate groups. Moreover, no significant difference in the behavior of bare core QDs and QDs capped with an inorganic Zn(Se,S) gradient shell was observed. The results paralleled those achieved by treating animals with an equivalent dose of indium salts, confirming the preferred bonding type of In³⁺ ions in Hydra tissues. In conclusion, by focusing on the chemical identity of indium along a 48 h long journey of QDs in Hydra, we describe a fast degradation process, in the absence of evident toxicity. These data pave the way to new paradigms to be considered in the biocompatibility assessment of QD-based biomedical applications, with greater emphasis on the dynamics of in vivo biotransformations, and suggest strategies to drive the design of future applied materials for nanotechnology-based diagnosis and therapeutics.

TRAIL acts synergistically with iron oxide nanocluster-mediated magneto- and photothermia

Targeting TRAIL (Tumor necrosis factor (TNF)-Related Apoptosis-Inducing Ligand) receptors for cancer therapy remains challenging due to tumor cell resistance and poor preparations of TRAIL or its derivatives. Herein, to optimize its therapeutic use, TRAIL was grafted onto iron oxide nanoclusters (NCs) with the aim of increasing its pro-apoptotic potential through nanoparticle-mediated magnetic hyperthermia (MHT) or photothermia (PT). Methods: The nanovector, NC@TRAIL, was characterized in terms of size, grafting efficiency, and potential for MHT and PT. The therapeutic function was assessed on a TRAIL-resistant breast cancer cell line, MDA-MB-231, wild type (WT) or TRAIL-receptor-deficient (DKO), by combining complementary methylene blue assay and flow cytometry detection of apoptosis and necrosis. Results: Combined with MHT or PT under conditions of "moderate hyperthermia" at low concentrations, NC@TRAIL acts synergistically with the TRAIL receptor to increase the cell death rate beyond what can be explained by the mere global elevation of temperature. In contrast, all results are consistent with the idea that there are hotspots, close to the nanovector and, therefore, to the membrane receptor, which cause disruption of the cell membrane. Furthermore, nanovectors targeting other membrane receptors, unrelated to the TNF superfamily, were also found to cause tumor cell damage upon PT. Indeed, functionalization of NCs by transferrin (NC@Tf) or human serum albumin (NC@HSA) induces tumor cell killing when combined with PT, albeit less efficiently than NC@TRAIL. Conclusions: Given that magnetic nanoparticles can easily be functionalized with molecules or proteins recognizing membrane receptors, these results should pave the way to original remote-controlled antitumoral targeted thermal therapies.

Flower-like Mn-Doped Magnetic Nanoparticles Functionalized with αvβ3-Integrin-Ligand to Efficiently Induce Intracellular Heat after Alternating Magnetic Field Exposition, Triggering Glioma Cell Death

Despite the potential of magnetic nanoparticles (NPs) to mediate intracellular hyperthermia when exposed to an alternating magnetic field (AMF), several studies indicate that the intracellular heating capacity of magnetic NPs depends on factors such as cytoplasm viscosity, nanoparticle aggregation within subcellular compartments, and dipolar interactions. In this work, we report the design and synthesis of monodispersed flowerlike superparamagnetic manganese iron oxide NPs with maximized SAR (specific absorption rate) and evaluate their efficacy as intracellular heaters in the human tumor-derived glioblastoma cell line U87MG. Three main strategies to tune the particle anisotropy of the core and the surface to reach the maximum heating efficiency were adopted: (1) varying the crystalline anisotropy by inserting a low amount of Mn²⁺ in the inverse spinel structure, (2) varying the NP shape to add an additional anisotropy source while keeping the superparamagnetic behavior, and (3) maximizing NP-cell affinity through conjugation with a biological targeting molecule to reach the NP concentration required to increase the temperature within the cell. We investigate possible effects produced by these improved NPs under the AMF (f = 96 kHz, H = 47 kA/m) exposure in the glioblastoma cell line U87MG by monitoring the expression of hsp70 gene and reactive oxygen species (ROS) production, as both effects have been described to be induced by increasing the intracellular temperature. The induced cell responses include cellular membrane permeabilization and rupture with concomitant high ROS appearance and hsp70 expression, followed by cell death. The responses were largely limited to cells that contained the NPs exposed to the AMF. Our results indicate that the developed strategies to optimize particle anisotropy in this work are a promising guidance to improve the heating efficiency of magnetic NPs in the human glioma cell line.

DNA-Coated Gold Nanoparticles for the Detection of mRNA in Live Hydra Vulgaris Animals

Advances in nanoparticle design have led to the development of nanoparticulate systems that can sense intracellular molecules, alter cellular processes, and release drugs to specific targets in vitro. In this work, we demonstrate that oligonucleotide-coated gold nanoparticles are suitable for the detection of mRNA in live Hydra vulgaris, a model organism, without affecting the animal's integrity. We specifically focus on the detection of Hymyc1 mRNA, which is responsible for the regulation of the balance between stem cell self-renewal and differentiation. Myc deregulation is found in more than half of human cancers, thus the ability to detect in vivo related mRNAs through innovative fluorescent systems is of outmost interest.

An Integrated Multilevel Analysis Profiling Biosafety and Toxicity Induced by Indium- and Cadmium-Based Quantum Dots in Vivo

Indium phosphide quantum dots (QDs) have emerged as a new class of fluorescent nanocrystals for manifold applications, from biophotonics to nanomedicine. Recent efforts in improving the photoluminescence quantum yield, the chemical stability and the biocompatibility turned them into a valid alternative to well established Cd-based nanocrystals. In vitro studies provided first evidence for the lower toxicity of In-based QDs. Nonetheless, an urgent need exists for further assessment of the potential toxic effects in vivo. Here we use the freshwater polyp Hydra vulgaris, a well-established model previously adopted to assess the toxicity of CdSe/CdS nanorods and CdTe QDs. A systematic multilevel analysis was carried out in vivo, ex vivo, and in vitro comparing toxicity end points of CdSe- and InP-based QDs, passivated by ZnSe/ZnS shells and surface functionalized with penicillamine. Final results demonstrate that both the chemical composition of the QD core (InP vs CdSe) and the shell play a crucial role for final outcomes. Remarkably, in absence of in vivo alterations, cell and molecular alterations revealed hidden toxicity aspects, highlighting the biosafety of InP-based nanocrystals and outlining the importance of integrated multilevel analyses for proper QDs risk assessment.

Aggregation effects on the magnetic properties of iron oxide colloids

Magnetic nanoparticles (MNPs), and in particular iron oxide nanoparticles (mainly magnetite and maghemite), are being widely used in the form of aqueous colloids for biomedical applications. In such colloids, nanoparticles tend to form assemblies, either aggregates, if the union is permanent, or agglomerates, if it is reversible. These clustering processes have a strong impact on the MNPs' properties that are often not well understood. In this review, the causes and consequences of MNPs aggregation/agglomeration are reviewed and discussed. Special attention has been paid to the impact of the MNPs aggregation/agglomeration on their magnetic properties and heating properties, when exposed to an alternating magnetic field in the frame of magnetic hyperthermia. In addition, a model system with MNPs of two different sizes coated with three different molecules oleic acid, meso-2, 3-dimercaptosuccinic acid and poly(maleic anhydride-alt-1-octadecene) has been characterized and the results used to support the ideas reviewed.

Triggering antitumoural drug release and gene expression by magnetic hyperthermia

Magnetic nanoparticles (MNPs) are promising tools for a wide array of biomedical applications. One of their most outstanding properties is the ability to generate heat when exposed to alternating magnetic fields, usually exploited in magnetic hyperthermia therapy of cancer. In this contribution, we provide a critical review of the use of MNPs and magnetic hyperthermia as drug release and gene expression triggers for cancer therapy. Several strategies for the release of chemotherapeutic drugs from thermo-responsive matrices are discussed, providing representative examples of their application at different levels (from proof of concept to in vivo applications). The potential of magnetic hyperthermia to promote in situ expression of therapeutic genes using vectors that contain heat-responsive promoters is also reviewed in the context of cancer gene therapy.

Magnetically-responsive DDS

Magnetic-responsive drug delivery systems have received great attention due to the possibility of building theranostic systems. The application of a non-invasive external stimuli as a magnetic field that also allows the imaging and localization of the devices and the release of therapeutic drugs means a great opportunity for the development of new treatments to prevent diseases such as cancer. This chapter will focus on smart materials based on magnetic nanoparticles that have been studied for the formulation of such delivery systems and their synergic effect in combination with drugs for potential applications in the biomedical field. In addition, the possibility of applying hyperthermia at the macro and nanoscale levels and their implications will be discussed.

Intermittent time-set technique controlling the temperature of magnetic-hyperthermia-ablation for tumor therapy

Magnetic-hyperthermia-ablation is considered as an effective and minimally invasive technology for tumor therapy. However, inappropriate temperature control could induce an excessively high temperature which brings potential safety problems and limits clinical transformation of this technique. Herein, aiming to control the temperature during magnetic hyperthermia ablation, we develop an intermittent time-set technique for temperature control in magnetic hyperthermia ablation of tumors using a polylactic-co-glycolic acid (PLGA)-Fe3O4 implant. In vitro, the intermittent time is set as follows: tubes are continuously heated for 110 seconds. Then the heating process is paused for 20 seconds, and then the tubes are reheated for 10 seconds, followed by repeating the last two processes. The temperature elevation profile upon magnetic hyperthermia interestingly also demonstrates good controllability despite some differences in time-setting between in vitro and in vivo. The in vivo results show the temperature fluctuates within the range of 6.45 ± 1.34 °C after reaching the target temperature. Furthermore, we observe the deformation of an implant employing three-dimensional (3D) ultrasound to better understand the temperature change. The results show no significant deformation of the implant after being heated. The microscopic images prove that this simple technique can successfully cause tumor regression. This temperature control technique provides great benefits for hyperthermia ablation against tumors, advancing the magnetic hyperthermal ablation technology in clinical translation.

Effect of Surface Chemistry and Associated Protein Corona on the Long-Term Biodegradation of Iron Oxide Nanoparticles In Vivo

The protein corona formed on the surface of a nanoparticle in a biological medium determines its behavior in vivo. Herein, iron oxide nanoparticles containing the same core and shell, but bearing two different surface coatings, either glucose or poly(ethylene glycol), were evaluated. The nanoparticles' protein adsorption, in vitro degradation, and in vivo biodistribution and biotransformation over four months were investigated. Although both types of nanoparticles bound similar amounts of proteins in vitro, the differences in the protein corona composition correlated to the nanoparticles biodistribution in vivo. Interestingly, in vitro degradation studies demonstrated faster degradation for nanoparticles functionalized with glucose, whereas the in vivo results were opposite with accelerated biodegradation and clearance of the nanoparticles functionalized with poly(ethylene glycol). Therefore, the variation in the degradation rate observed in vivo could be related not only to the molecules attached to the surface, but also with the associated protein corona, as the key role of the adsorbed proteins on the magnetic core degradation has been demonstrated in vitro.

In Vivo Imaging of Local Gene Expression Induced by Magnetic Hyperthermia

The present work aims to demonstrate that colloidal dispersions of magnetic iron oxide nanoparticles stabilized with dextran macromolecules placed in an alternating magnetic field can not only produce heat, but also that these particles could be used in vivo for local and noninvasive deposition of a thermal dose sufficient to trigger thermo-induced gene expression. Iron oxide nanoparticles were first characterized in vitro on a bio-inspired setup, and then they were assayed in vivo using a transgenic mouse strain expressing the luciferase reporter gene under transcriptional control of a thermosensitive promoter. Iron oxide nanoparticles dispersions were applied topically on the mouse skin or injected subcutaneously with Matrigel™ to generate so-called pseudotumors. Temperature was monitored continuously with a feedback loop to control the power of the magnetic field generator and to avoid overheating. Thermo-induced luciferase expression was followed by bioluminescence imaging 6 h after heating. We showed that dextran-coated magnetic iron oxide nanoparticle dispersions were able to induce in vivo mild hyperthermia compatible with thermo-induced gene expression in surrounding tissues and without impairing cell viability. These data open new therapeutic perspectives for using mild magnetic hyperthermia as noninvasive modulation of tumor microenvironment by local thermo-induced gene expression or drug release.

Semiconducting polymers are light nanotransducers in eyeless animals

Current implant technology uses electrical signals at the electrode-neural interface. This rather invasive approach presents important issues in terms of performance, tolerability, and overall safety of the implants. Inducing light sensitivity in living organisms is an alternative method that provides groundbreaking opportunities in neuroscience. Optogenetics is a spectacular demonstration of this, yet is limited by the viral transfection of exogenous genetic material. We propose a nongenetic approach toward light control of biological functions in living animals. We show that nanoparticles based on poly(3-hexylthiophene) can be internalized in eyeless freshwater polyps and are fully biocompatible. Under light, the nanoparticles modify the light response of the animals, at two different levels: (i) they enhance the contraction events of the animal body, and (ii) they change the transcriptional activation of the opsin3-like gene. This suggests the establishment of a seamless and biomimetic interface between the living organism and the polymer nanoparticles that behave as light nanotransducers, coping with or amplifying the function of primitive photoreceptors.

Control of Wnt/β-Catenin Signaling Pathway in Vivo via Light Responsive Capsules

The possibility to remotely manipulate intracellular pathways in single cells is among the current goals of biomedicine, demanding new strategies to control cell function and reprogramming cell fate upon external triggering. Optogenetics is one approach in this direction, allowing specific cell stimulation by external illumination. Here, we developed optical switchers of an ancient and highly conserved system controlling a variety of developmental and adult processes in all metazoans, from Hydra to mammals, the Wnt/β-catenin signaling pathway. An intracellular modulator of the Wnt pathway was enclosed into polyelectrolyte multilayer microcapsules engineered to include self-tracking (i.e., fluorescence labeling) and light mediated heating functionalities (i.e., plasmonic nanoparticles). Capsules were delivered in vivo to Hydra and NIR triggered drug release caused forced activation of the Wnt pathway. The possibility to remotely manipulate the Wnt pathway by optical switchers may be broadly translated to achieve spatiotemporal control of cell fate for new therapeutic strategies.

Inhibition of heat-shock protein 90 sensitizes liver cancer stem-like cells to magnetic hyperthermia and enhances anti-tumor effect on hepatocellular carcinoma-burdened nude mice

PURPOSE

To explore the thermoresistance and expression of heat-shock protein 90 (HSP90) in magnetic hyperthermia-treated human liver cancer stem-like cells (LCSCs) and the effects of a heat-shock protein HSP90 inhibitor 17-allylamino-17-demethoxgeldanamycin (17-AAG) on hepatocellular carcinoma-burdened nude mice.

METHODS

CD90(+) LCSCs were isolated by magnetic-activated cell sorting from BEL-7404. Spheroid formation, proliferation, differentiation, drug resistance, and tumor formation assays were performed to identify stem cell characteristics. CD90-targeted thermosensitive magnetoliposomes (TMs)-encapsulated 17-AAG (CD90@17-AAG/TMs) was prepared by reverse-phase evaporation and its characteristics were studied. Heat tolerance in CD90(+) LCSCs and the effect of CD90@17-AAG/TMs-mediated heat sensitivity were examined in vitro and in vivo.

RESULTS

CD90(+) LCSCs showed significant stem cell-like properties. The 17-AAG/TMs were successfully prepared and were spherical in shape with an average size of 128.9±7.7 nm. When exposed to magnetic hyperthermia, HSP90 was up-regulated in CD90(+) LCSCs. CD90@17-AAG/TMs inhibited the activity of HSP90 and increased the sensitivity of CD90(+) LCSCs to magnetic hyperthermia.

CONCLUSION

The inhibition of HSP90 could sensitize CD90(+) LCSCs to magnetic hyperthermia and enhance its anti-tumor effects in vitro and in vivo.

Impact of Carbon Nano-Onions on Hydra vulgaris as a Model Organism for Nanoecotoxicology

The toxicological effects of pristine and chemically modified carbon nano-onions (CNOs) on the development of the freshwater polyp Hydra vulgaris were investigated in order to elucidate the ecotoxicological effects of CNOs. Chemical modifications of the CNOs were accomplished by surface functionalization with benzoic acid, pyridine and pyridinium moieties. thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy confirmed the covalent surface functionalization of CNOs. Hydra specimens were exposed to the carbon nanomaterials by prolonged incubation within their medium. Uptake was monitored by optical microscopy, and the toxicological effects of the CNOs on Hydra behavior, morphology, as well as the long-term effects on the development and reproductive capability were examined. The obtained data revealed the absence of adverse effects of CNOs (in the range 0.05-0.1 mg/L) in vivo at the whole animal level. Together with previously performed in vitro toxicological analyses, our findings indicate the biosafety of CNOs and the feasibility of employing them as materials for biomedical applications.