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Gold Nanoparticles and Radiofrequency in Experimental Models for Hepatocellular Carcinoma
Abstract
Unlabelled:
Hepatocellular carcinoma (HCC) is one of the most lethal and chemo-refractory cancers, clearly, alternative treatment strategies are needed. We utilized 10nm gold nanoparticles as a scaffold to synthesize nanoconjugates bearing a targeting antibody (cetuximab, C225) and gemcitabine. Loading efficiency of gemcitabine on the gold nanoconjugates was 30%. Targeted gold nanoconjugates in combination with RF were selectively cytotoxic to EGFR expressing Hep3B and SNU449 cells when compared to isotype particles with/without RF (P<0.05). In animal experiments, targeted gold nanoconjugates halted the growth of subcutaneous Hep3B xenografts in combination with RF exposure (P<0.05). These xenografts also demonstrated increased apoptosis, necrosis and decreased proliferation compared to controls. Normal tissues were unharmed. We have demonstrated that non-invasive RF-induced hyperthermia when combined with targeted delivery of gemcitabine is more effective and safe at dosages ~275-fold lower than the current clinically-delivered systemic dose of gemcitabine.
From the clinical editor:
In a model of hepatocellular carcinoma, the authors demonstrate that non-invasive RF-induced hyperthermia applied with cetuximab targeted delivery of Au NP-gemcitabine conjugate is more effective and safe at dosages ~ 275-fold lower than the current clinically-used systemic dose of gemcitabine.
... At smaller scales, to enhance the penetration of the DDSs to tissues and cells, nanoparticles (for example, gold, carbon nanotubes, iron-based MNPs, platinum and quantum dots) have been employed [104][105][106] . Aside from carrying therapeutic cargos (for example, antibodies) to the site of action, cancer cell ablation via heating has been demonstrated with these particles. ...
... Aside from carrying therapeutic cargos (for example, antibodies) to the site of action, cancer cell ablation via heating has been demonstrated with these particles. For example, it has been shown in a model of hepatocellular carcinoma (one of the most lethal and chemo-refractory cancers) that non-invasive RF-induced hyperthermia combined with cetuximab targeted delivery of a gold nanoparticle (AuNP)-gemcitabine conjugate is more safe and effective at dosages ~275-fold lower than the current clinically used systemic dose of gemcitabine (Fig. 4j) 106 . ...
Wireless on-demand drug delivery systems exploit exogenous stimuli—acoustic waves, electric fields, magnetic fields and electromagnetic radiation—to trigger drug carriers. The approach allows drugs to be delivered with controlled release profiles and minimal off-target effects. Recent advances in electronics and materials engineering have led to the development of sophisticated systems designed for specific applications. Here we review the development of wireless on-demand drug delivery systems. We examine the working mechanisms, applications, advantages and limitations of systems that are triggered by electric fields, magnetic fields or electromagnetic radiation. We also provide design guidelines for the development of such systems, including key metrics for evaluating the practicality of different smart drug delivery systems. This Review examines wireless on-demand drug delivery systems that are triggered by electric fields, magnetic fields or electromagnetic radiation, and provides design guidelines for the development of such systems.
... The in vivo data of combined treatment also showed significant retardation of the tumor growth compared to mono-therapy with chemotherapeutic agents [148]. Raoof et al. [149] evaluated the therapeutic efficacy of antibody (C225)-conjugated AuNPs loaded with gemcitabine coupled with radiofrequency-induced hyperthermia against hepatocellular carcinoma Hep3B cells. Their results demonstrated that the targeted AuPNs, in combination with hyperthermia, stopped the growth of subcutaneous Hep3B xenografts. ...
... Increased necrosis, apoptosis and reduced proliferation were also observed in these xenografts compared to controls. They also reported that the radiofrequency-induced hyperthermia combined with the targeted delivery of gemcitabine is more effective and safe at a remarkably low dosage (about 275-fold lower than the conventional dose of this agent) [149]. In a recent study, Mirrahimi et al. [150] developed a new nano-complex containing alginate nanogel co-loaded with AuNPs and cisplatin as the combination treatment agent of chemotherapy and PTT (by 532 nm laser light) against BALB/c mice bearing CT26 model. ...
The conventional cancer treatment modalities such as radiotherapy and chemotherapy suffer from several limitations; hence, their efficiency needs to be improved with other complementary modalities. Hyperthermia, as an adjuvant therapeutic modality for cancer, can result in a synergistic effect on radiotherapy (radiosensitizer) and chemotherapy (chemosensitizer). Conventional hyperthermia methods affect both tumoral and healthy tissues and have low specificity. In addition, a temperature gradient generates in the tissues situated along the path of the heat source, which is a more serious for deep-seated tumors. Nanoparticles (NPs)-induced hyperthermia can resolve these drawbacks through localization around/within tumoral tissue and generating local hyperthermia. Although there are several review articles dealing with NPs-induced hyperthermia, lack of a paper discussing the combination of NPs-induced hyperthermia with the conventional chemotherapy or radiotherapy is tangible. Accordingly, the main focus of the current paper is to summarize the principles of NPs-induced hyperthermia and more importantly its synergic effects on the conventional chemotherapy or radiotherapy. The heat-producing nanostructures such as gold NPs, iron oxide NPs, and carbon NPs, as well as the non-heat-producing nanostructures, such as lipid-based, polymeric, and silica-based NPs, as the carrier for heat-producing NPs, are discussed and their pros and cons highlighted.
... The choice of AuNPs as a therapeutic agent to be delivered by the GO-PEI nanoplatform proved to be promising due to its performance in inhibiting the signaling of several important pathways for cancer biology, showing that AuNPs specifically target cancer cells. It has been shown that when inside cancer cells, AuNPs target tumor suppressor genes and oncogenes [54][55][56]. ...
Aim: This report proposes using the Hill model to assess the benchmark dose, the 50% lethal dose, the cooperativity and the dissociation constant while analyzing cell viability data using nanomaterials to evaluate the antitumor potential while combined with radiofrequency therapy. Materials & methods: A nanocomposite was synthesized (graphene oxide–polyethyleneimine–gold) and the viability was evaluated using two tumor cell lines, namely LLC-WRC-256 and B16-F10. Results: Our findings demonstrated that while the nanocomposite is biocompatible against the LLC-WRC-256 and B16-F10 cancer cell lines in the absence of radiofrequency, the application of radiofrequency enhances the cell toxicity by orders of magnitude. Conclusion: This result points to prospective studies with the tested cell lines using tumor animal models.
... 4,11 The RF system he designed is known as a "Kanzius Machine" and is used by many groups to study hyperthermia with gold nanoparticles. 4,12,13,14 Since the first publications on heat production by gold nanoparticles, the heating mechanism during exposure of colloidal gold to RF electromagnetic waves has been the subject of debate in the literature. 15,16,17,18 Careful calculations of the Joule heat resulting from induced currents within the gold nanoparticles was shown to be insufficient to account for the temperature increase by the gold colloids under RF exposure. ...
Gold nanoparticles can be used as efficient nanotransducers of RF electromagnetic energy into heat, rendering them as excellent candidates for noninvasive hyperthermia treatment of cancer with minimal side effects. Here we report on experimental heating profiles of gold nanoparticles of various sizes (5 nm, 10 nm, 20 nm, and 30 nm) exposed to a capacitively coupled RF field at various frequencies (6.5 MHz, 8.2 MHz, 10 MHz, 13.56 MHz, 15 MHz, and 17 MHz). We find that the heating rates depend on the size of the gold nanoparticles and the frequency of RF irradiation. We use the energy balance equations to numerically simulate the heating profiles of the gold colloidal solutions.
... Two fluid-based dopants were considered, normal saline and colloidal gold. While saline infusion has been clinically used at different concentrations to dope RFA target tissue [12,20], colloidal gold is little used in clinical practice [21]. The use of a fluid-based dopant before and during RFA is associated with the following two phenomena: (1) higher substrate electrical conductivity, especially if hypertonic saline (> 3%) is used instead of normal saline (0.9%); and (2) roll-off is delayed due to rehydration of the desiccated tissue (only with continuous infusion or periodic administration of bolus during RFA [20]). ...
Background
The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g., gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes.
Methods
The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group).
Results
The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone.
Conclusions
Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.
Cancer remains a serious health problem in terms of incidence and mortality worldwide. As a result, researchers are working to identify new chemotherapeutic therapies or, potentially, to use innovative drug delivery methods in existing therapies. Recently, there has been a lot of interest in using nanocarriers as drug delivery systems, particularly for the treatment of cancer. Several novel nanocarrier-mediated drug delivery systems are currently being used to deliver chemotherapeutic agents to specific sites. Polymeric nanoparticles, liposomes, polymeric micelles, carbon nanotubes, dendrimers, solid lipid nanoparticles, magnetic nanoparticles and quantum dots are all examples of important nanocarriers. One of the most often prescribed chemotherapeutics for first-line therapy is gemcitabine hydrochloride, which has a broad spectrum of effects. Gemcitabine hydrochloride is an intriguing example of a drug for which various nanostructured targeted delivery methods are being explored over history. Even though some of these systems already exist on the market, there is continued research on this topic and new solutions are continually sought. In this context, the present review examines gemcitabine not as a specific drug, but as a proof of concept study that has drawn upon a wide range of innovative nanotechnology approaches.
Graphical Abstract
The selective and efficient delivery of bioactive molecules to sites of interest remains a formidable challenge in medicine. In recent years, it has been shown that stimuli-responsive drug delivery systems display several advantages over traditional drug administration such as an improved pharmacokinetic profile and the desirable ability to gain control over release. Light emerged as one of the most powerful stimuli due to its high biocompatibility, spatio-temporal control, and non-invasiveness. On the road to clinical translation, various chemical systems of high complexity have been reported with the aim to improve efficacy, safety, and versatility of drug delivery under complex biological conditions. For future research on the chemical design of such photo-controlled nanomedicines, it is essential to gain an understanding of their in vivo translation and efficiency. Here, we discuss photo-controlled nanomedicines that have been evaluated in vivo and provide an overview of the state-of-the-art that should guide future research design.
Antibody‐based cancer therapy, one of the most significant therapeutic strategies, has achieved considerable success and progress over the past decades. Nevertheless, obstacles including limited tumor penetration, short circulation half‐lives, undesired immunogencity, and off‐target side effects remain to be overcome for the antibody‐based cancer treatment. Owing to the rapid development of nanotechnology, antibody‐containing nanomedicines that have been extensively explored to overcome these obstacles have already demonstrated to have enhanced anticancer efficacy and clinical translation potential. This review intends to offer an overview of the advancements of antibody‐incorporated nanoparticulate systems in cancer treatment, together with the nontrivial challenges faced by these next‐generation nanomedicines. Diverse strategies of antibody immobilization, formats of antibodies, types of cancer‐associated antigens, and anticancer mechanisms of antibody‐containing nanomedicines are provided and discussed in this review, with an emphasis on the latest applications. The current limitations and future research directions on antibody‐containing nanomedicines are also discussed from different perspectives to provide new insights into the construction of anticancer nanomedicines. This article is protected by copyright. All rights reserved
The specific cytotoxic effects of nanoparticles on tumor cells may be used in future antitumor clinical applications. Gold nanoparticles (AuNPs) have been reported to produce potent cytotoxic effects; however, the precise mechanism is unclear. In this study, AuNPs were synthesized; the average size of the particles was 62.2 ± 6 nm with smooth surface and multiple shapes, which were determined using transmission electron microscopy and field emission scanning electron microscopy. The selected area electron diffraction patterns suggested that the synthesized AuNPs were crystalline. The X‐ray photoelectron spectroscopy (XPS) spectrum of the synthesized AuNPs has presented an intense peak at 100 eV, signifying the entire composition of Au in the developed AuNPs. This synthesized AuNPs showed the most potent efficacy in prostate cancer cells, regardless of whether or not they were androgen dependent. Secretome determinations using two‐dimensional difference in‐gel electrophoresis (2D‐DIGE), followed by enzyme‐linked immunosorbent assay and quantitative reverse transcriptase–polymerase chain reaction validations, have identified a series of secretory proteins that were dysregulated by AuNP treatment in prostate cancer cells, many of which are highly involved in cytokine–chemokine functions, including CXCL3, interleukin‐10, CCL2, and matrix metalloproteinase 9 (MMP9). Further research on molecular mechanism has indicated that AuNPs can trigger the secretion of anticancer factors and myeloid cell‐polarizing factors from tumor cells through MMP9 inhibition. These results have clearly signified the cytotoxic potential of AuNPs for treating prostate cancer and may provide a novel direction for prostate cancer therapy in the future.
Background: The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g. gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes.
Methods: The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: 1) non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group).
Results: The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone.
Conclusions: Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.
There is a renewed interest in developing high-intensity short wave capacitively-coupled radiofrequency (RF) electric-fields for nanoparticle-mediated tumor-targeted hyperthermia. However, the direct thermal effects of such high-intensity electric-fields (13.56 MHZ, 600 W) on normal and tumor tissues are not completely understood. In this study, we investigate the heating behavior and dielectric properties of normal mouse tissues and orthotopically-implanted human hepatocellular and pancreatic carcinoma xenografts. We note tumor-selective hyperthermia (relative to normal mouse tissues) in implanted xenografts that can be explained on the basis of differential dielectric properties. Furthermore, we demonstrate that repeated RF exposure of tumor-bearing mice can result in significant anti-tumor effects compared to control groups without detectable harm to normal mouse tissues.
The evaluation of heat production from gold nanoparticles (AuNPs) irradiated with radio-frequency (RF) energy has been problematic due to Joule heating of their background ionic buffer suspensions. Insights into the physical heating mechanism of nanomaterials under RF excitations must be obtained if they are to have applications in fields such as nanoparticle-targeted hyperthermia for cancer therapy. By developing a purification protocol that allows for highly stable and concentrated solutions of citrate-capped AuNPs to be suspended in high-resistivity water, we show herein, for the first time, that heat production is only evident for AuNPs of diameters ≤10 nm, indicating a unique size-dependent heating behavior not previously observed. Heat production has also shown to be linearly dependent on both AuNP concentration and total surface area and was severely attenuated upon AuNP aggregation. These relationships have been further validated using permittivity analysis across a frequency range of 10 MHz–3 GHz as well as static conductivity measurements. Theoretical evaluations suggest that the heating mechanism can be modeled by the electrophoretic oscillation of charged AuNPs across finite length scales in response to a time-varying electric field. It is anticipated these results will assist future development of nanoparticle-assisted heat production by RF fields for applications such as targeted cancer hyperthermia.
Enhanced heating of nanoparticles for applications such as thermoacoustic imaging and therapeutic heat delivery is considered. The optimum electrical conductivity to achieve maximum electromagnetic energy deposition in a given nanoparticle is obtained, with emphasis on rf frequencies, where plasmon resonances associated with negative permittivity are generally not possible. Spheres, coated spheres, nanowires, and carbon nanotubes are considered. In all cases, it is found that relatively small conductivity values (e.g., σ≪1 S / m for spheres) provide the maximum absorption of rf energy, and thus maximizes heat production in the nanoparticle. Therefore, lossy dielectrics may be a better choice for maximizing nanoparticle heat production than metallic particles.
Gold nanoparticles (GNPs) are nontoxic, can be functionalized with ligands, and preferentially accumulate in tumors. We have developed a 13.56-MHz RF-electromagnetic field (RFEM) delivery system capable of generating high E-fleld strengths required for noninvasive, noncontact heating of GNPs. The bulk heating and specific heating rates were measured as a function of NP size and concentration. It was found that heating is both size and concentration dependent, with 5 nm particles producing a 50.6 ± 0.2°C temperature rise in 30 s for 25 μg/mL gold (125 W input). The specific heating rate was also size and concentration dependent, with 5 nm particles producing a specific heating rate of 356 ± 78 kW/g gold at 16 μg/mL (125 W input). Furthermore, we demonstrate that cancer cells incubated with GNPs are killed when exposed to 13.56 MHz RF-EM fields. Compared to cells that were not incubated with GNPs, three out of four RF-treated groups showed a significant enhancement of cell death with GNPs (p <; 0.05). GNP-enhanced cell killing appears to require temperatures above 50°C for the experimental parameters used in this study. Transmission electron micrographs show extensive vacuolization with the combination of GNPs and RF treatment.
Purpose:
To investigate the schedule-dependency of 2',2'difluorodeoxycytidine (dFdC, Gemcitabine) combined with hyperthermia (HT), in vitro as well as in vivo.
Materials and methods:
Rat R-1 rhabdomyosarcoma cells were treated with various concentrations of dFdC for 70 min, 4 h and 24 h. After various time intervals HT (60 min at 43 degrees C) was applied. Cell survival was determined by clonogenic assays. Female Wag/Rij rats bearing R-1 tumours on the hind limbs were treated with dFdC (20 mg/kg), with locally applied HT (60 min at 43 degrees C) or with a combined treatment using different time intervals (0, 24 and 48 h). Tumour growth delay (TGD) and normal tissue toxicity were assessed.
Results:
With dFdC alone, significant cytotoxicity was observed after a 24 h-exposure. Except for the 24 h-exposure, HT reduced the cytotoxicity of dFdC in simultaneous applications. An enhanced cytotoxic effect was found when HT was applied 20 h after a 4 h-incubation with dFdC. In vivo, HT applied 48 h after dFdC-administration resulted in potentiation of the effect of dFdC with respect to TGD without an increase in toxicity.
Conclusions:
The efficacy of dFdC combined with HT is schedule-dependent both in vitro and in vivo. The addition of HT enhances the effectiveness of dFdC in the R-1 tumour model.
The evaluation of heat production from gold nanoparticles (AuNPs) irradiated with radiofrequency (RF) energy has been problematic due to Joule heating of their background ionic buffer suspensions. Insights into the physical heating mechanism of nanomaterials under RF excitations must be obtained if they are to have applications in fields such as nanoparticle-targeted hyperthermia for cancer therapy. By developing a purification protocol which allows for highly-stable and concentrated solutions of citrate-capped AuNPs to be suspended in high-resistivity water, we show herein, for the first time, that heat production is only evident for AuNPs of diameters ≤ 10 nm, indicating a unique size-dependent heating behavior not previously observed. Heat production has also shown to be linearly dependent on both AuNP concentration and total surface area, and severely attenuated upon AuNP aggregation. These relationships have been further validated using permittivity analysis across a frequency range of 10 MHz to 3 GHz, as well as static conductivity measurements. Theoretical evaluations suggest that the heating mechanism can be modeled by the electrophoretic oscillation of charged AuNPs across finite length scales in response to a time-varying electric field. It is anticipated these results will assist future development of nanoparticle-assisted heat production by RF fields for applications such as targeted cancer hyperthermia.
Single-walled carbon nanotubes (SWNTs) have remarkable physicochemical properties that may have several medical applications. The authors have discovered a novel property of SWNTs—heat release in a radiofrequency (RF) field—that they hypothesized may be used to produce thermal cytotoxicity in malignant cells.
Functionalized, water-soluble SWNTs were exposed to a noninvasive, 13.56-megahertz RF field, and heating characteristics were measured with infrared thermography. Three human cancer cell lines were incubated with various concentrations of SWNTs and then treated in the RF field. Cytotoxicity was measured by fluorescence-activated cell sorting. Hepatic VX2 tumors in rabbits were injected with SWNTs or with control solutions and were treated in the RF field. Tumors were harvested 48 hours later to assess viability.
The RF field induced efficient heating of aqueous suspensions of SWNTs. This phenomenon was used to produce a noninvasive, selective, and SWNT concentration-dependent thermal destruction in vitro of human cancer cells that contained internalized SWNTs. Direct intratumoral injection of SWNTs in vivo followed by immediate RF field treatment was tolerated well by rabbits bearing hepatic VX2 tumors. At 48 hours, all SWNT-treated tumors demonstrated complete necrosis, whereas control tumors that were treated with RF without SWNTs remained completely viable. Tumors that were injected with SWNTs but were not treated with RF also were viable.
The current results suggested that SWNTs targeted to cancer cells may allow noninvasive RF field treatments to produce lethal thermal injury to the malignant cells. Now, the authors are developing SWNTs coupled with cancer cell-targeting agents to enhance SWNT uptake by cancer cells while limiting uptake by normal cells. Cancer 2007.
It was natural that the exceptional properties of gold and the mystique surrounding the metal should induce man to seek medicinal
applications for it. These attempts met with no apparent success until a few decades ago, when the efficacy of gold compounds
in the treatment of rheumatoid arthritis was confirmed. Nevertheless, they form an important, and sometimes colourful, part
of the history of pharmacology and medicine.
Unlabelled:
The use of noninvasive radiofrequency (RF) electric fields as an energy source for thermal activation of nanoparticles within cancer cells could be a valuable addition to the emerging field of nano-mediated cancer therapies. Based on investigations of cell death through hyperthermia, and offering the ability for total-body penetration by RF fields, this technique is thought to complement and possibly outperform existing nano-heat treatments that utilize alternative heat production via optical or magnetic stimuli. However, it remains a challenge to understand fully the complex RF-nanoparticle-intracellular interactions before full system optimization can be engineered. Herein we have shown that liver cancer cells can selectively internalize antibody-conjugated gold nanoparticles (AuNPs) through receptor-mediated endocytosis, with the nanoparticles predominantly accumulating and aggregating within cytoplasmic endolysosomes. After exposure to an external RF field, nonaggregated AuNPs absorbed and dissipated energy as heat, causing thermal damage to the targeted cancer cells. We also observed that RF absorption and heat dissipation is dependent on solubility of AuNPs in the colloid, which is pH dependent. Furthermore, by modulating endolysosomal pH it is possible to prevent intracellular AuNP aggregation and enhance thermal cytotoxicity in hepatocellular cancer cells.
From the clinical editor:
Gold nanoparticles absorb energy from RF fields and can exert hyperthermic effects leading to cell death. Combining this known effect with antibody-based targeting of the nanoparticles, selective cancer specific hyperthermia induced cell death therapies can be designed, as demonstrated in this article.