Non-invasive radiofrequency ablation of malignancies mediated by quantum dots, gold nanoparticles and carbon nanotubes

Computer simulation-based nanothermal field and tissue damage analysis for cardiac tumor ablation

Radiofrequency ablation is a nominally invasive technique to eradicate cancerous or non-cancerous cells by heating. However, it is still hampered to acquire a successful cell destruction process due to inappropriate RF intensities that will not entirely obliterate tumorous tissues, causing in treatment failure. In this study, we are acquainted with a nanoassisted RF ablation procedure of cardiac tumor to provide better outcomes for long-term survival rate without any recurrences. A three-dimensional thermo-electric energy model is employed to investigate nanothermal field and ablation efficiency into the left atrium tumor. The cell death model is adopted to quantify the degree of tissue injury while injecting the Fe3O4 nanoparticles concentrations up to 20% into the target tissue. The results reveal that when nanothermal field extents as a function of tissue depth (10 mm) from the electrode tip, the increasing thermal rates were approximately 0.54362%, 3.17039%, and 7.27397% for the particle concentration levels of 7%, 10%, and 15% compared with no-particle case. In the 7% Fe3O4 nanoparticles, 100% fractional damage index is achieved after ablation time of 18 s whereas tissue annihilation approach proceeds longer to complete for no-particle case. The outcomes indicate that injecting nanoparticles may lessen ablation time in surgeries and prevent damage to adjacent healthy tissue.

Recent advances on hyperthermia therapy applications of carbon-based nanocomposites

Generally, hyperthermia is referred to the composites capability to increase local temperature in such a way that the generated heat would lead to cancerous or bacteria cells destruction, with minimum damage to normal tissue cells. Many different materials have been utilized for hyperthermia application via different heat generating methods. Carbon-based nanomaterials consisting of graphene oxide (GO), carbon nanotube (CNT), carbon dot (CD) and carbon quantum dot (CQD), nanodiamond (ND), fullerene and carbon fiber (CF), have been studied significantly for different applications including hyperthermia due to their biocompatibility, biodegradability, chemical and physical stability, thermal and electrical conductivity and in some cases photothermal conversion. Therefore, in this comprehensive review, a structure-based view on carbon nanomaterials application in hyperthermia therapy of cancer and bacteria via various methods such as optical, magnetic, ultrasonic and radiofrequency-induced hyperthermia is presented.

Dendrimers: Advancements and Potential Applications in Cancer Diagnosis and Treatment-An Overview

Cancer is a leading cause of death worldwide, and the main treatment methods for this condition are surgery, chemotherapy, and radiotherapy. These treatment methods are invasive and can cause severe adverse reactions among organisms, so nanomaterials are increasingly used as structures for anticancer therapies. Dendrimers are a type of nanomaterial with unique properties, and their production can be controlled to obtain compounds with the desired characteristics. These polymeric molecules are used in cancer diagnosis and treatment through the targeted distribution of some pharmacological substances. Dendrimers have the ability to fulfill several objectives in anticancer therapy simultaneously, such as targeting tumor cells so that healthy tissue is not affected, controlling the release of anticancer agents in the tumor microenvironment, and combining anticancer strategies based on the administration of anticancer molecules to potentiate their effect through photothermal therapy or photodynamic therapy. The purpose of this review is to summarize and highlight the possible uses of dendrimers regarding the diagnosis and treatment of oncological conditions.

Radiofrequency-Activated Pyroptosis of Bi-Valent Gold Nanocluster for Cancer Immunotherapy

Pyroptosis is gasdermin-mediated programmed necrosis that exhibits promising potential application in cancer immunotherapy, and the main challenge lies in how to provoke specific pyroptosis of tumor cells. Here, biGC@PNA with a precisely stoichiometric ratio of Au(I) ion/Au(0) atom induced pyroptosis of tumor cells by its radiofrequency (RF)-heating effect. An in vitro/in vivo assay on 4T1 tumor cells indicates RF-activated pyroptosis of tumor cells elicits a robust ICD effect, enhancing the synergistic antitumor efficacy of biGC@PNA with decitabine, significantly suppressing tumor metastasis and relapse by provoking systemic antitumor immune responses. Utilizing RF-activated pyroptotic immune responses, biGC@PNA efficiently enhances the antitumor efficacy of αPD-1 immunotherapy under RF irradiation and provides a promising strategy for improving cancer immunotherapy by the noninvasive RF field with high clinical transformation potential.

Radiofrequency ablation in the treatment of hepatocellular carcinoma

OBJECTIVE

The purpose of this article is to discuss the use, comparative efficacy, and research progress of radiofrequency ablation (RFA), alone or in combination with other therapies, for the treatment of hepatocellular carcinoma (HCC).

METHOD

To search and summarize the basic and clinical studies of RFA in recent years.

RESULTS

RFA is one of the radical treatment methods listed in the guidelines for the diagnosis and treatment of HCC. It has the characteristics of being minimally invasive and safe and can obtain good local tumor control, and it can improve the local immune ability, improve the tumor microenvironment and enhance the efficacy of chemotherapy drugs. It is commonly used for HCC treatment before liver transplantation and combined ALPPS and hepatectomy for HCC. In addition, the technology of RFA is constantly developing. The birth of noninvasive, no-touch RFA technology and equipment and the precise RFA concept have improved the therapeutic effect of RFA.

CONCLUSION

RFA has good local tumor control ability, is minimally invasive, is safe and has other beneficial characteristics. It plays an increasingly important role in the comprehensive treatment strategy of HCC. Whether RFA alone or combined with other technologies expands the surgical indications of patients with HCC and provides more benefits for HCC patients needs to be determined.

Nanomaterials in cancer: Reviewing the combination of hyperthermia and triggered chemotherapy

Nanoparticle mediated hyperthermia has been explored as a method to increase cancer treatment efficacy by heating tumours inside-out. With that purpose, nanoparticles have been designed and their properties tailored to respond to external stimuli and convert the supplied energy into heat, therefore inducing damage to tumour cells. Moreover, the combination of hyperthermia with chemotherapy has been described as a more effective strategy due to the synergy between the high temperature and the drug's effects, also associated with a remote controlled and on-demand drug release. In this review, the methods behind nanoparticle mediated hyperthermia, namely material design, external stimuli response and energy conversion will be discussed and critically analysed. We will address the most relevant studies on hyperthermia and temperature triggered drug release for cancer treatment. Finally, the advantages, difficulties and challenges of this therapeutic strategy will be discussed, while giving insight for future developments.

Advances in Cancer Therapeutics: Conventional Thermal Therapy to Nanotechnology-Based Photothermal Therapy

In this review, advancement in cancer therapy that shows a transition from conventional thermal therapies to laser-based photothermal therapies is discussed. Laser-based photothermal therapies are gaining popularity in cancer therapeutics due to their overall outcomes. In photothermal therapy, light is converted into heat to destruct the various types of cancerous growth. The role of nanoparticles as a photothermal agent is emphasized in this review article. Magnetic, as well as non-magnetic, nanoparticles have been effectively used in the photothermal-based cancer therapies. The discussion includes a critical appraisal of in vitro and in vivo, as well as the latest clinical studies completed in this area. Plausible evidence suggests that photothermal therapy is a promising avenue in the treatment of cancer.

Exploiting gold nanoparticles for diagnosis and cancer treatments

Gold nanoparticles (AuNPs) represent a relatively simple nanosystem to be synthesised and functionalized. AuNPs offer numerous advantages over different nanomaterials, primarily due to highly optimized protocols for their production with sizes in the range 1-150 nm and shapes, spherical, nanorods (AuNRs), nanocages, nanostars or nanoshells (AuNSs), just to name a few. AuNPs possess unique properties both from the optical and chemical point of view. AuNPs can absorb and scatter light with remarkable efficiency. Their outstanding interaction with light is due to the conduction electrons on the metal surface undergoing a collective oscillation when they are excited by light at specific wavelengths. This oscillation, known as a localized surface plasmon resonance, causes the absorption and scattering intensities of AuNPs to be significantly higher than identically sized non-plasmonic nanoparticles. In addition, AuNP absorption and scattering properties can be tuned by controlling the particle size, shape, and the local refractive index near the particle surface. By the chemical side, AuNPs offer the advantage of functionalization with therapeutic agents through covalent and ionic binding, which can be useful for biomedical applications, with particular emphasis on cancer treatments. Functionalized AuNPs exhibit good biocompatibility and controllable distribution patterns when delivered in cells and tissues, which make them particularly fine candidates for the basis of innovative therapies. Currently, major available AuNP-based cancer therapeutic approaches are the photothermal therapy (PTT) or photodynamic therapy (PDT). PTT and PDT rely upon irradiation of surface plasmon resonant AuNPs (previously delivered in cancer cells) by light, in particular, in the near-infrared range. Under irradiation, AuNPs surface electrons are excited and resonate intensely, and fast conversion of light into heat takes place in about 1 ps. The cancer cells are destroyed by the induced hyperthermia, i.e. the condition under which cells are subject to temperature in the range of 41 °C-47 °C for tens of minutes. The review is focused on the description of the optical and thermal properties of AuNPs that underlie their continuous and progressive exploitation for diagnosis and cancer therapy.

Tailor-Made Nanomaterials for Diagnosis and Therapy of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers worldwide due to its aggressiveness and the challenge to early diagnosis and treatment. In recent decades, nanomaterials have received increasing attention for diagnosis and therapy of PDAC. However, these designs are mainly focused on the macroscopic tumor therapeutic effect, while the crucial nano-bio interactions in the heterogeneous microenvironment of PDAC remain poorly understood. As a result, the majority of potent nanomedicines show limited performance in ameliorating PDAC in clinical translation. Therefore, exploiting the unique nature of the PDAC by detecting potential biomarkers together with a deep understanding of nano-bio interactions that occur in the tumor microenvironment is pivotal to the design of PDAC-tailored effective nanomedicine. This review will introduce tailor-made nanomaterials-enabled laboratory tests and advanced noninvasive imaging technologies for early and accurate diagnosis of PDAC. Moreover, the fabrication of a myriad of tailor-made nanomaterials for various PDAC therapeutic modalities will be reviewed. Furthermore, much preferred theranostic multifunctional nanomaterials for imaging-guided therapies of PDAC will be elaborated. Lastly, the prospects of these nanomaterials in terms of clinical translation and potential breakthroughs will be briefly discussed.

Percutaneous ultrasound guided PEG-coated gold nanoparticles enhanced radiofrequency ablation in liver

To investigate the effects of PEG-coated gold nanoparticles on ablation zone volumes following in vivo radiofrequency ablation of porcine liver. This prospective study was performed following institutional animal care and committee approval was used. Radiofrequency ablations were performed in the livers of ten Sus scrofa domesticus swines. During each ablation, 10 mL (mL) of Peg-coated gold nanoparticles at two different concentrations (0.5 mg/mL and 0.01 mg/mL) were injected through the electrode channel into the target zone. For the control group, 10 mL of physiological saline was used. Five to ten minutes after each ablation, contrast enhanced ultrasound (CEUS) was performed to evaluate the volume of the coagulation zone. On day five we performed another CEUS and the animals were sacrificed. Treated tissues were explanted for quantification of the ablation zones' volumes. Hematoxylin and eosin (H&E) staining was also performed for histologic analysis. A total of 30 ablations were performed in the livers. The mean coagulation zone volume as measured by CEUS on day 5 after RFA was: 21.69 ± 3.39 cm3, 19.22 ± 5.77 cm3, and 8.80 ± 3.33 cm3 for N1, N2 and PS respectively. The coagulation zone volume after N1 and N2 treatments was significantly higher compared to PS treatment (p < 0.001 and p = 0.025 respectively). There was no difference between N1 and N2 treatment (p = 0.60). In our proof-of concept, pilot study we have shown for the first time that when injected directly into the target tissue during RFA, gold nanoparticles can substantially increase the coagulation zone.

Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): computer modeling and ex vivo experiments

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.

Thermal ablation of biological tissues in disease treatment: A review of computational models and future directions

Percutaneous thermal ablation has proven to be an effective modality for treating both benign and malignant tumours in various tissues. Among these modalities, radiofrequency ablation (RFA) is the most promising and widely adopted approach that has been extensively studied in the past decades. Microwave ablation (MWA) is a newly emerging modality that is gaining rapid momentum due to its capability of inducing rapid heating and attaining larger ablation volumes, and its lesser susceptibility to the heat sink effects as compared to RFA. Although the goal of both these therapies is to attain cell death in the target tissue by virtue of heating above 50°C, their underlying mechanism of action and principles greatly differs. Computational modelling is a powerful tool for studying the effect of electromagnetic interactions within the biological tissues and predicting the treatment outcomes during thermal ablative therapies. Such a priori estimation can assist the clinical practitioners during treatment planning with the goal of attaining successful tumour destruction and preservation of the surrounding healthy tissue and critical structures. This review provides current state-of-the-art developments and associated challenges in the computational modelling of thermal ablative techniques, viz., RFA and MWA, as well as touch upon several promising avenues in the modelling of laser ablation, nanoparticles assisted magnetic hyperthermia and non-invasive RFA. The application of RFA in pain relief has been extensively reviewed from modelling point of view. Additionally, future directions have also been provided to improve these models for their successful translation and integration into the hospital work flow.

Recent Advances in Magnetite Nanoparticle Functionalization for Nanomedicine

Functionalization of nanomaterials can enhance and modulate their properties and behaviour, enabling characteristics suitable for medical applications. Magnetite (Fe3O4) nanoparticles are one of the most popular types of nanomaterials used in this field, and many technologies being already translated in clinical practice. This article makes a summary of the surface modification and functionalization approaches presented lately in the scientific literature for improving or modulating magnetite nanoparticles for their applications in nanomedicine.

External stimulus responsive inorganic nanomaterials for cancer theranostics

Cancer is a highly intelligent system of cells, that works together with the body to thrive and subsequently overwhelm the host in order for its survival. Therefore, treatment regimens should be equally competent to outsmart these cells. Unfortunately, it is not the case with current therapeutic practices, the reason why it is still one of the most deadly adversaries and an imposing challenge to healthcare practitioners and researchers alike. With rapid nanotechnological interventions in the medical arena, the amalgamation of diagnostic and therapeutic functionalities into a single platform, theranostics provides a never before experienced hope of enhancing diagnostic accuracy and therapeutic efficiency. Additionally, the ability of these nanotheranostic agents to perform their actions on-demand, i.e. can be controlled by external stimulus such as light, magnetic field, sound waves and radiation has cemented their position as next generation anti-cancer candidates. Numerous reports exist of such stimuli-responsive theranostic nanomaterials against cancer, but few have broken through to clinical trials, let alone clinical practice. This review sheds light on the pros and cons of a few such theranostic nanomaterials, especially inorganic nanomaterials which do not require any additional chemical moieties to initiate the stimulus. The review will primarily focus on preclinical and clinical trial approved theranostic agents alone, describing their success or failure in the respective stages.

Multifunctional fluorescent iron quantum clusters for non-invasive radiofrequency ablationof cancer cells

This work reports the potential of iron quantum clusters (FeQCs) as a hyperthermia agent for cancer, by testing its in-vitro response to shortwave (MHz range), radiofrequency (RF) waves non-invasively. Stable, fluorescent FeQCs of size ∼1 nm prepared by facile aqueous chemistry from endogenous protein haemoglobin were found to give a high thermal response, with a ΔT ∼50 °C at concentrationsas low as165 μg/mL. The as-prepared nanoclusters purified by lyophilization as well as dialysis showed a concentration, power and time-dependent RF response, with the lyophilized FeQCs exhibiting pronounced heating effects. FeQCs were found to be cytocompatible to NIH-3T3 fibroblast and 4T1 cancer cells treated at concentrations upto 1000 μg/mL for 24 h. Upon incubation with FeQCs and exposure to RF waves, significant cancer cell death was observed which proves its therapeutic ability. The fluorescent ability of the clusters could additionally be utilized for imaging cancer cells upon excitation at ∼450 nm. Further, to demonstrate the feasibility of imparting additional functionality such as drug/biomolecule/dye loading to FeQCs, they were self assembled with cationic polymers to form nanoparticles. Self assembly did not alter the RF heating potential of FeQCs and additionally enhanced its fluorescence. The multifunctional fluorescent FeQCs therefore show good promise as a novel therapeutic agent for RF hyperthermia and drug loading.

Radiofrequency electric field hyperthermia with gold nanostructures: role of particle shape and surface chemistry

Hyperthermia treatment of cancerous cells has been recently developed drastically with the help of nanostructures. Heating of gold nanoparticles in non-invasive radiofrequency electric field (RF-EF) is a promising and unique technique for cancer hyperthermia. However, because of differences between particles (i.e. their surface chemistry and dispersion medium) and between RF-EF sources, the research community has not reached a consensus yet. Here, we report the results of investigations on heating of gold nanoparticles and gold nanorods under RF-EF and feasibility of in-vitro cancer hyperthermia. The heating experiments were performed to investigate the role of particle shape and surface chemistry (CTAB, citrate and PEG molecules). In-vitro hyperthermia was performed on human pancreatic cancer cell (MIA Paca-2) with PEG-coated GNPs and GNRs at concentrations that were found non-toxic based on the results of cytotoxicity assay. Application of RF-EF on cells treated with PEG-GNPs and PEG-GNRs proved highly effective in killing cells.

Nano-assisted radiofrequency ablation of clinically extracted irregularly-shaped liver tumors

Radiofrequency ablation (RFA) for liver tumors is a minimally invasive procedure that uses electrical energy and heat to destroy cancer cells. One of the critical factors that impedes its successful outcome is the use of inappropriate radiofrequency levels that will not completely destroy the target tumor tissues, resulting in therapy failure. Additionally, the surrounding healthy tissues may suffer from serious damage due to excessive ablation. To address these challenges, this work proposes the employment of injected nanoparticles to thermally promote the ablation efficacy of conventional RFA. A three-dimensional finite difference analysis is employed to simulate the RFA treatment. Based on the data acquired from measured experiments, the simulation results have demonstrated close agreement with experimental data with a maximum discrepancy of within ±8.7%. Several types of nanoparticles were selected to evaluate their influences on liver tissue's thermal and electrical properties. We analysed the effects of nanoparticles on liver RFA via a tumor rending process incorporating several clinically-extracted tumor profiles and vascular systems. Simulations were conducted to explore the temperature difference responses between conventional RFA treatment and one with the inclusion of assisted nanoparticles on several irregularly-shaped tumors. Results have indicated that applying selected nanoparticles with high thermal conductivity and electrical conductivity on the targeted tissue zone promotes heating rate while sustaining a similar ablation zone that experiences lower maximum temperature when compared with the conventional RFA treatment. In sum, incorporating thermally-enhancing nanoparticles promotes heat transfer during the RFA treatment, resulting in improved ablation efficiency.

Non-Invasive Radiofrequency Field Treatment to Produce Hepatic Hyperthermia: Efficacy and Safety in Swine

The Kanzius non-invasive radio-frequency hyperthermia system (KNiRFH) has been investigated as a treatment option for hepatic hyperthermia cancer therapy. The treatment involves exposing the patient to an external high-power RF (13.56 MHz) electric field, whereby the propagating waves penetrate deep into the tumor causing targeted heating based on differential tissue dielectric properties. However, a comprehensive examination of the Kanzius system alongside any associated toxicities and its ability to induce hepatic hyperthermia in larger animal models, such as swine, are the subjects of the work herein. Ten Yucatan female mini-swine were treated with the KNiRFH system. Two of the pigs were treated a total of 17 times over a five-week period to evaluate short- and long-term KNiRFH-associated toxicities. The remaining eight pigs were subjected to single exposure sessions to evaluate heating efficacy in liver tissue. Our goal was to achieve a liver target temperature of 43°C and to evaluate toxicities and burns post-treatment. Potential toxicities were evaluated by contrast-enhanced MRI of the upper abdomen and blood work, including complete metabolic panel, complete blood count, and liver enzymes. The permittivities of subcutaneous fat and liver were also measured, which were used to calculate tissue specific absorption rates (SAR). Our results indicate negligible KNiRFH-associated toxicities; however, due to fat overheating, liver tissue temperature did not exceed 38.5°C. This experimental limitation was corroborated by tissue permittivity and SAR calculations of subcutaneous fat and liver. Significant steps must be taken to either reduce subcutaneous fat heating or increase localized heating, potentially through the use of KNiRFH-active nanomaterials, such as gold nanoparticles or single-walled carbon nanotubes, which have previously shown promising results in murine cancer models.

Temperature responsive porous silicon nanoparticles for cancer therapy - spatiotemporal triggering through infrared and radiofrequency electromagnetic heating

One critical functionality of the carrier system utilized in targeted drug delivery is its ability to trigger the release of the therapeutic cargo once the carrier has reached its target. External triggering is an alluring approach as it can be applied in a precise spatiotemporal manner. In the present study, we achieved external triggering through the porous silicon (PSi) nanoparticles (NPs) by providing a pulse of infrared or radiofrequency radiation. The NPs were grafted with a temperature responsive polymer whose critical temperature was tailored to be slightly above 37°C. The polymer coating improved the biocompatibility of the NPs significantly in comparison with their uncoated counterparts. Radiation induced a rapid temperature rise, which resulted in the collapse of the polymer chains facilitating the cargo release. Both infrared and radiofrequency radiation were able to efficiently trigger the release of the encapsulated drug in vitro and induce significant cell death in comparison to the control groups. Radiofrequency radiation was found to be more efficient in vitro, and the treatment efficacy was verified in vivo in a lung carcinoma (3LL) mice model. After a single intratumoral administration of the carrier system combined with radiofrequency radiation, there was clear suppression of the growth of the carcinoma and a prolongation of the survival time of the animals.

TOC IMAGE

The temperature responsive (TR) polymer grafted on the surface of porous silicon nanoparticles (PSi NPs) changes its conformation in response to the heating induced by infrared or radiofrequency radiation. The conformation change allows the loaded doxorubicin to escape from the pores, achieving controlled drug release from TR PSi NPs, which displayed efficacy against malignant cells both in vitro and in vivo.

Transferrin-Conjugated Biodegradable Graphene for Targeted Radiofrequency Ablation of Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is a clinically established therapy for hepatocellular carcinoma (HCC). However, because of poor radio-thermal conductivity of liver tissues, RFA is less efficient against relatively larger (>5 cm) liver tumors. Recently, nanoparticle-enabled RFA has emerged as a better strategy. On the basis of our recent understanding on biodegradability and novel electrothermal properties of graphene, herein, we report development of transferrin conjugated, biodegradable graphene (TfG) for RFA therapy. Cellular uptake studies using confocal microscopy and Raman imaging revealed significantly higher TfG uptake by HCC cells compared to bare graphene. TfG-treated cancer cells upon 5 min exposure to 100 W, 13.5 MHz RF showed >85% cell death, which was 4 times greater than bare graphene. Further evaluation in 3D (3 Dimensional) HCC culture system as well as in vivo rat models demonstrated uniform destruction of tumor cells throughout the 3D microenvironment. This study reveals the potential of molecularly targeted graphene for augmented RFA therapy of liver tumor.

Radiofrequency ablation of drug-resistant cancer cells using molecularly targeted carboxyl-functionalized biodegradable graphene

Under ultralow radiofrequency (RF) power, transferrin-conjugated graphene nanoparticles can thermally ablate drug- or radiation-resistant cancer cells very effectively. The results suggest that graphene-based RF hyperthermia can be an efficient method to manage drug-/radiation-resistant cancers.

Biomedical applications of gold nanomaterials: opportunities and challenges

In the past few years, there has been an unprecedented development of gold nanomaterials (AuNMs) for potential clinical applications. Owing to their advantageous physical, chemical, and biological properties, AuNMs have attracted great attention in the nanomedicine arena for applications in biological sensing, biomedical imaging, drug delivery, and photothermal therapy. Their tunable size, shape, and surface characteristics coupled with excellent biocompatibility render them ideal candidates for translation from bench-top to bedside. This review summarizes the recent research on the applications of AuNM with a focus on biomedical diagnostics and therapeutics. The bio-interaction of these NM with cells and their in vivo responses are presented. After reviewing these potential applications, future challenges and prospects are discussed and the suitability of how AuNMs are used as effective tools in clinical medicine is assessed.

Knockdown of glutamate cysteine ligase catalytic subunit by siRNA causes the gold nanoparticles-induced cytotoxicity in lung cancer cells

Gold nanoparticles (GNPs) have shown promising medical applications in cancer treatment involved in the regulation of intracellular redox balance. Previously, we have reported that GNPs can trigger apoptosis and necrosis in human lung cancer cells (A549) when L-buthionine-sulfoximine (BSO) was used to decrease the expression of intracellular glutathione (GSH). Herein, we investigated the cytotoxicity of GNPs toward lung cancer cells under the glutamate cysteine ligase catalytic subunit (GCLC) was silenced by siRNA. Our results showed that GNPs cause apoptosis and necrosis in cells transfected with GCLC siRNA by elevating intracellular reactive oxygen species (ROS). These findings demonstrated that the regulation of glutathione synthesis by GCLC siRNA in A549 cells can initiate the gold nanoparticles-induced cytotoxicity.

Bionanotechnology and the future of glioma

Designer nanoscaled materials have the potential to revolutionize diagnosis and treatment for glioma. This review summarizes current progress in nanoparticle-based therapies for glioma treatment including targeting, drug delivery, gene delivery, and direct tumor ablation. Preclinical and current human clinical trials are discussed. Although progress in the field has been significant over the past decade, many successful strategies demonstrated in the laboratory have yet to be implemented in human clinical trials. Looking forward, we provide examples of combined treatment strategies, which harness the potential for nanoparticles to interact with their biochemical environment, and simultaneously with externally applied photons or magnetic fields. We present our notion of the "ideal" nanoparticle for glioma, a concept that may soon be realized.

Therapeutic gold, silver, and platinum nanoparticles

There are an abundance of nanoparticle technologies being developed for use as part of therapeutic strategies. This review focuses on a narrow class of metal nanoparticles that have therapeutic potential that is a consequence of elemental composition and size. The most widely known of these are gold nanoshells that have been developed over the last two decades for photothermal ablation in superficial cancers. The therapeutic effect is the outcome of the thickness and diameter of the gold shell that enables fine tuning of the plasmon resonance. When these metal nanoparticles are exposed to the relevant wavelength of light, their temperature rapidly increases. This in turn induces a localized photothermal ablation that kills the surrounding tumor tissue. Similarly, gold nanoparticles have been developed to enhance radiotherapy. The high-Z nature of gold dramatically increases the photoelectric cross-section. Thus, the photoelectric effects are significantly increased. The outcome of these interactions is enhanced tumor killing with lower doses of radiation, all while sparing tissue without gold nanoparticles. Silver nanoparticles have been used for their wound healing properties in addition to enhancing the tumor-killing effects of anticancer drugs. Finally, platinum nanoparticles are thought to serve as a reservoir for platinum ions that can induce DNA damage in cancer cells. The future is bright with the path to clinical trials is largely cleared for some of the less complex therapeutic metal nanoparticle systems.

Gold-gold sulfide nanoshell as a novel intensifier for anti-tumor effects of radiofrequency fields

OBJECTIVES

Several studies have been carried out to investigate the effect of various nanoparticles exposed to radiofrequency (RF) waves on cancerous tissues. In this study, a colon carcinoma tumor model was irradiated by RF in the presence of gold-gold sulfide (GGS) nanoshells.

MATERIALS AND METHODS

Synthesis and characterization of GGS nanoshells were initially performed. CT26 cells were subcutaneously injected into the flank of BALB/c mice to create the colon carcinoma tumor models. Then the tumors were subjected to different treatments. Treatment factors included intratumoral injection of GGS and RF radiation. Different groups were considered as control with no treatment, receiving GGS, RF irradiated and simultaneous administration of GGS and RF. Efficacy of the treatments was evaluated by daily monitoring of tumor volume and recording the relative changes in it, the time needed for a 5-fold increase in the volume of tumor (T5) and utilizing pathologic studies to determine the lost volume of the tumors.

RESULTS

In comparison with control group, tumor growth was not markedly inhibited in the groups receiving only GGS or RF, while in the group receiving GGS and RF, tumor growth was effectively inhibited compared with the other groups. In addition, the lost volume of the tumor and T5 was markedly higher in groups receiving GGS and RF compared with other groups.

CONCLUSION

This study showed that RF radiation can markedly reduce the tumor growth in presence of GGS. Hence, it can be predicted that GGS nanoshells convert sub-lethal effects of noninvasive RF fields into lethal damages.

Radiofrequency-triggered release for on-demand delivery of therapeutics from titania nanotube drug-eluting implants

Aim: This study aimed to demonstrate radiofrequency (RF)-triggered release of drugs and drug carriers from drug-eluting implants using gold nanoparticles as energy transducers. Materials & methods: Titanium wire with a titania nanotube layer was used as an implant loaded with indomethacin and micelles (tocopheryl PEG succinate) as a drug and drug carrier model. RF signals were generated from a customized RF generator to trigger in vitro release. Results & discussion: Within 2.5 h, 18 mg (92%) of loaded drug and 14 mg (68%) of loaded drug carriers were released using short RF exposure (5 min), compared with 5 mg (31%) of drug and 2 mg (11%) of drug carriers without a RF trigger. Gold nanoparticles can effectively function as RF energy transducers inside titania nanotubes for rapid release of therapeutics at arbitrary times. Conclusion: The results of this study show that RF is a promising strategy for triggered release from implantable drug delivery systems where on-demand delivery of therapeutics is required.

Original submitted 19 November 2012; Revised submitted 1 April 2013

Emerging advances in nanomedicine with engineered gold nanostructures

Gold nanostructures possess unique characteristics that enable their use as contrast agents, as therapeutic entities, and as scaffolds to adhere functional molecules, therapeutic cargo, and targeting ligands. Due to their ease of synthesis, straightforward surface functionalization, and non-toxicity, gold nanostructures have emerged as powerful nanoagents for cancer detection and treatment. This comprehensive review summarizes the progress made in nanomedicine with gold nanostructures (1) as probes for various bioimaging techniques including dark-field, one-photon and two-photon fluorescence, photothermal optical coherence tomography, photoacoustic tomography, positron emission tomography, and surface-enhanced Raman scattering based imaging, (2) as therapeutic components for photothermal therapy, gene and drug delivery, and radiofrequency ablation, and (3) as a theranostic platform to simultaneously achieve both cancer detection and treatment. Distinct from other published reviews, this article also discusses the recent advances of gold nanostructures as contrast agents and therapeutic actuators for inflammatory diseases including atherosclerotic plaque and arthritis. For each of the topics discussed above, the fundamental principles and progress made in the past five years are discussed. The review concludes with a detailed future outlook discussing the challenges in using gold nanostructures, cellular trafficking, and translational considerations that are imperative for rapid clinical viability of plasmonic nanostructures, as well as the significance of emerging technologies such as Fano resonant gold nanostructures in nanomedicine.

Protocols for assessing radiofrequency interactions with gold nanoparticles and biological systems for non-invasive hyperthermia cancer therapy

Cancer therapies which are less toxic and invasive than their existing counterparts are highly desirable. The use of RF electric-fields that penetrate deep into the body, causing minimal toxicity, are currently being studied as a viable means of non-invasive cancer therapy. It is envisioned that the interactions of RF energy with internalized nanoparticles (NPs) can liberate heat which can then cause overheating (hyperthermia) of the cell, ultimately ending in cell necrosis. In the case of non-biological systems, we present detailed protocols relating to quantifying the heat liberated by highly-concentrated NP colloids. For biological systems, in the case of in vitro experiments, we describe the techniques and conditions which must be adhered to in order to effectively expose cancer cells to RF energy without bulk media heating artifacts significantly obscuring the data. Finally, we give a detailed methodology for in vivo mouse models with ectopic hepatic cancer tumors.

A review of therapeutic aptamer conjugates with emphasis on new approaches

The potential to emulate or enhance antibodies with nucleic acid aptamers while lowering costs has prompted development of new aptamer-protein, siRNA, drug, and nanoparticle conjugates. Specific focal points of this review discuss DNA aptamers covalently bound at their 3' ends to various proteins for enhanced stability and greater pharmacokinetic lifetimes in vivo. The proteins can include Fc tails of IgG for opsonization, and the first component of complement (C1q) to trigger complement-mediated lysis of antibiotic-resistant Gram negative bacteria, cancer cells and possibly some parasites during vulnerable stages. In addition, the 3' protein adduct may be a biotoxin, enzyme, or may simply be human serum albumin (HSA) or a drug known to bind HSA, thereby retarding kidney and other organ clearance and inhibiting serum exonucleases. In this review, the author summarizes existing therapeutic aptamer conjugate categories and describes his patented concept for PCR-based amplification of double-stranded aptamers followed by covalent attachment of proteins or other agents to the chemically vulnerable overhanging 3' adenine added by Taq polymerase. PCR amplification of aptamers could dramatically lower the current $2,000/gram cost of parallel chemical oligonucleotide synthesis, thereby enabling mass production of aptamer-3'-protein or drug conjugates to better compete against expensive humanized monoclonal antibodies.