Use of Tumor Necrosis Factor–alpha-coated Gold Nanoparticles to Enhance Radiofrequency Ablation in a Translational Model of Renal Tumors

The influence of size and surface chemistry on the bioavailability, tissue distribution and toxicity of gold nanoparticles in zebrafish (Danio rerio)

Gold nanoparticles (AuNPs) are widely used in biomedicine and their specific properties including, size, geometrics, and surface coating, will affect their fate and behaviour in biological systems. These properties are well studied for their intended biological targets, but there is a lack of understanding on the mechanisms by which AuNPs interact in non-target organisms when they enter the environment. We investigated the effects of size and surface chemistry of AuNPs on their bioavailability, tissue distribution and potential toxicity using zebrafish (Danio rerio) as an experimental model. Larval zebrafish were exposed to fluorescently tagged AuNPs of different sizes (10-100 nm) and surface modifications (TNFα, NHS/PAMAM and PEG), and uptake, tissue distribution and depuration rates were measured using selective-plane illumination microscopy (SPIM). The gut and pronephric tubules were found to contain detectable levels of AuNPs, and the concentration-dependent accumulation was related to the particle size. Surface addition of PEG and TNFα appeared to enhance particle accumulation in the pronephric tubules compared to uncoated particles. Depuration studies showed a gradual removal of particles from the gut and pronephric tubules, although fluorescence indicating the presence of the AuNPs remained in the pronephros 96 h after exposure. Toxicity assessment using two transgenic zebrafish reporter lines, however, revealed no AuNP-related renal injury or cellular oxidative stress. Collectively, our data show that AuNPs used in medical applications across the size range 40-80 nm, are bioavailable to larval zebrafish and some may persist in renal tissue, although their presence did not result in measurable toxicity with respect to pronephric organ function or cellular oxidative stress for short term exposures.

Rational Design of Biomaterials to Potentiate Cancer Thermal Therapy

Cancer thermal therapy, also known as hyperthermia therapy, has long been exploited to eradicate mass lesions that are now defined as cancer. With the development of corresponding technologies and equipment, local hyperthermia therapies such as radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound, have has been validated to effectively ablate tumors in modern clinical practice. However, they still face many shortcomings, including nonspecific damages to adjacent normal tissues and incomplete ablation particularly for large tumors, restricting their wide clinical usage. Attributed to their versatile physiochemical properties, biomaterials have been specially designed to potentiate local hyperthermia treatments according to their unique working principles. Meanwhile, biomaterial-based delivery systems are able to bridge hyperthermia therapies with other types of treatment strategies such as chemotherapy, radiotherapy and immunotherapy. Therefore, in this review, we discuss recent progress in the development of functional biomaterials to reinforce local hyperthermia by functioning as thermal sensitizers to endow more efficient tumor-localized thermal ablation and/or as delivery vehicles to synergize with other therapeutic modalities for combined cancer treatments. Thereafter, we provide a critical perspective on the further development of biomaterial-assisted local hyperthermia toward clinical applications.

Lessons learned from immunological characterization of nanomaterials at the Nanotechnology Characterization Laboratory

Nanotechnology carriers have become common in pharmaceutical products because of their benefits to drug delivery, including reduced toxicities and improved efficacy of active pharmaceutical ingredients due to targeted delivery, prolonged circulation time, and controlled payload release. While available examples of reduced drug toxicity through formulation using a nanocarrier are encouraging, current data also demonstrate that nanoparticles may change a drug’s biodistribution and alter its toxicity profile. Moreover, individual components of nanoparticles and excipients commonly used in formulations are often not immunologically inert and contribute to the overall immune responses to nanotechnology-formulated products. Said immune responses may be beneficial or adverse depending on the indication, dose, dose regimen, and route of administration. Therefore, comprehensive toxicology studies are of paramount importance even when previously known drugs, components, and excipients are used in nanoformulations. Recent data also suggest that, despite decades of research directed at hiding nanocarriers from the immune recognition, the immune system’s inherent property of clearing particulate materials can be leveraged to improve the therapeutic efficacy of drugs formulated using nanoparticles. Herein, I review current knowledge about nanoparticles’ interaction with the immune system and how these interactions contribute to nanotechnology-formulated drug products’ safety and efficacy through the lens of over a decade of nanoparticle characterization at the Nanotechnology Characterization Laboratory.

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.

Fiber-Optic Distributed Sensing Network for Thermal Mapping of Gold Nanoparticles-Mediated Radiofrequency Ablation

In this work, we report the design of an optical fiber distributed sensing network for the 2-dimensional (2D) in situ thermal mapping of advanced methods for radiofrequency thermal ablation. The sensing system is based on six high-scattering MgO-doped optical fibers, interleaved by a scattering-level spatial multiplexing approach that allows simultaneous detection of each fiber location, in a 40 × 20 mm grid (7.8 mm2 pixel size). Radiofrequency ablation (RFA) was performed on bovine phantom, using a pristine approach and methods mediated by agarose and gold nanoparticles in order to enhance the ablation properties. The 2D sensors allow the detection of spatiotemporal patterns, evaluating the heating properties and investigating the repeatability. We observe that agarose-based ablation yields the widest ablated area in the best-case scenario, while gold nanoparticles-mediated ablation provides the best trade-off between the ablated area (53.0-65.1 mm2, 61.5 mm2 mean value) and repeatability.

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.

DM1 Loaded Ultrasmall Gold Nanoparticles Display Significant Efficacy and Improved Tolerability in Murine Models of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide with poor prognosis and limited options for treatment. Life expectancy after diagnosis is short; the currently available treatments are not well tolerated and have limited clinical benefit. There is a clear unmet clinical need for the development of new treatments. In this study, ultrasmall, 2 nm gold core nanoparticles (MidaCore) conjugated with the potent maytansine analogue DM1 (MTC-100038) were assessed as a systemic nanomedicine for the treatment of hepatocellular carcinoma. The platform improved overall tolerability of DM1, permitting ∼3-fold higher levels of drug to be administered compared to free drug. Dose for dose, MTC-100038 also facilitated delivery of ∼2.0-fold higher ( p = 0.039) levels of DM1 to the tumor compared to free DM1. MTC-100038 produced significant efficacy (tumor growth index ∼102%; p = <0.0001), in several murine xenograft models of HCC, and was superior to both free DM1 and the current standard of care, sorafenib. Furthermore, MTC-100038 displayed potent (nM) in vitro activity in various HCC primary patient derived cell lines and across various other different cancer cell types. These data demonstrate the potential of MidaCore nanoparticles to enhance tumor delivery of cytotoxic drugs and indicate MTC-100038 is worthy of further investigation as a potential treatment for HCC and other cancer types.

Gold Nanoparticles and Radio Frequency Field Interactions: Effects of Nanoparticle Size, Charge, Aggregation, Radio Frequency, and Ionic Background

In this study, we investigated experimentally the dependency of radio frequency (rf) absorption by gold nanoparticles (AuNPs) on frequency (10 kHz to 450 MHz), NP size (3.5, 17, and 36 nm), charge of the ligand shell (positive amino and negative carboxylic functional groups), aggregation state, and presence of electrolytes (0-1 M NaCl). In addition, we examined the effect of protein corona on the rf absorption by AuNPs. For the first time, rf energy absorption by AuNPs was analyzed in the 10 kHz to 450 MHz rf range. We have demonstrated that the previously reported rf heating of AuNPs can be solely attributed to the heating of the ionic background and AuNPs do not absorb noticeable rf energy regardless of the NP size, charge, aggregation, and presence of electrolytes. However, the formation of protein corona on the AuNP surface resulted in rf energy absorption by AuNP-albumin constructs, suggesting that protein corona might be partially responsible for the heating of AuNPs observed in vivo. The optimal frequency of rf absorption for the AuNP-albumin constructs is significantly higher than conventional 13.56 MHz, suggesting that the heating of AuNPs in rf field should be performed at considerably higher frequencies for better results in vivo.

Interaction of gold nanoparticles with proteins and cells

Gold nanoparticles (Au NPs) possess many advantages such as facile synthesis, controllable size and shape, good biocompatibility, and unique optical properties. Au NPs have been widely used in biomedical fields, such as hyperthermia, biocatalysis, imaging, and drug delivery. The broad application range may result in hazards to the environment and human health. Therefore, it is important to predict safety and evaluate therapeutic efficiency of Au NPs. It is necessary to establish proper approaches for the study of toxicity and biomedical effects. In this review, we first focus on the recent progress in biological effects of Au NPs at the molecular and cellular levels, and then introduce key techniques to study the interaction between Au NPs and proteins. Knowledge of the biomedical effects of Au NPs is significant for the rational design of functional nanomaterials and will help predict their safety and potential applications.

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.

Applications of nanoparticles in the detection and treatment of kidney diseases

Nanoparticles have emerged in the medical field as a technology well suited for the diagnosis and treatment of various disease states. They have been heralded as efficacious in terms of improved therapeutic efficacy and reduction of treatment side effects in some cases. Various nanomaterials have been developed that can be tagged with targeting moieties as well as with drug delivery and imaging capability or a combination of both as a theranostic agent. These nanomaterials have been investigated for treatment and detection of various pathological conditions. The emphasis of this review is to demonstrate current research and clinical applications for nanoparticles in the diagnosis and treatment of kidney diseases.

Induction of apoptosis by high-dose gold nanoparticles in nasopharyngeal carcinoma cells

OBJECTIVE

Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is a common cancer in southern Asia. Local recurrent disease and distant metastasis of NPC are still the unsolved problems. Recently, gold nanoparticles (AuNPs) have been developed as potential in vivo diagnostic and therapeutic agents. However, their role on nasopharyngeal cancer remains unknown. The object of this study is to investigate if AuNPs can be used as a new therapeutic agent for NPC by evaluating their anti-tumor effect in vitro.

METHODS

The AuNPs were prepared by the reduction of chloroauric acid to neutral gold. Their size distribution and microstructures were characterized by transmission electron microscopy (TEM). To evaluate their cytotoxic effect, NPC cell line TW01 and Human Nasal Epithelial Cells (HNEpC) were cultured in various concentrations of AuNPs for 3 days. Cell viability was evaluated by Trypan Blue viability assay while morphologic findings were observed via light microscopy. Terminal deoxynucleotidyltransferase-mediated dUPT nick end labeling (TUNEL) assay was used to detect apoptosis.

RESULTS

AuNPs prepared in this study had an average diameter of 20.5nm and they were observed under light microscopy as dark material aggregated in the cells after treatment. Contrary to the HNEpC, the AuNPs reduced cell viability of NPC cell in a concentration-dependant manner by Trypan Blue assay, especially at high concentration. Besides, cell apoptosis was demonstrated by positive TUNEL assay.

CONCLUSIONS

The AuNP possesses specific imaging properties and is cytotoxic to NPC cells at high concentrations.

Development of multigene expression signature maps at the protein level from digitized immunohistochemistry slides

Molecular classification of diseases based on multigene expression signatures is increasingly used for diagnosis, prognosis, and prediction of response to therapy. Immunohistochemistry (IHC) is an optimal method for validating expression signatures obtained using high-throughput genomics techniques since IHC allows a pathologist to examine gene expression at the protein level within the context of histologically interpretable tissue sections. Additionally, validated IHC assays may be readily implemented as clinical tests since IHC is performed on routinely processed clinical tissue samples. However, methods have not been available for automated n-gene expression profiling at the protein level using IHC data. We have developed methods to compute expression level maps (signature maps) of multiple genes from IHC data digitized on a commercial whole slide imaging system. Areas of cancer for these expression level maps are defined by a pathologist on adjacent, co-registered H&E slides, allowing assessment of IHC statistics and heterogeneity within the diseased tissue. This novel way of representing multiple IHC assays as signature maps will allow the development of n-gene expression profiling databases in three dimensions throughout virtual whole organ reconstructions.

Gold nanoprobes for theranostics

Gold nanoprobes have become attractive diagnostic and therapeutic agents in medicine and life sciences research owing to their reproducible synthesis with atomic level precision, unique physical and chemical properties, versatility of their morphologies, flexibility in functionalization, ease of targeting, efficiency in drug delivery and opportunities for multimodal therapy. This review highlights some of the recent advances and the potential for gold nanoprobes in theranostics.

Nanoparticle preconditioning for enhanced thermal therapies in cancer

Nanoparticles show tremendous promise in the safe and effective delivery of molecular adjuvants to enhance local cancer therapy. One important form of local cancer treatment that suffers from local recurrence and distant metastases is thermal therapy. In this article, we review a new concept involving the use of nanoparticle-delivered adjuvants to 'precondition' or alter the vascular and immunological biology of the tumor to enhance its susceptibility to thermal therapy. To this end, a number of opportunities to combine nanoparticles with vascular and immunologically active agents are reviewed. One specific example of preconditioning involves a gold nanoparticle tagged with a vascular targeting agent (i.e., TNF-α). This nanoparticle embodiment demonstrates preconditioning through a dramatic reduction in tumor blood flow and induction of vascular damage, which recruits a strong and sustained inflammatory infiltrate in the tumor. The ability of this nanoparticle preconditioning to enhance subsequent heat or cold thermal therapy in a variety of tumor models is reviewed. Finally, the potential for future clinical imaging to judge the extent of preconditioning and thus the optimal timing and extent of combinatorial thermal therapy is discussed.

Gas-phase production of gold-decorated silica nanoparticles

Gold-decorated silica nanoparticles were synthesized in a two-step process in which silica nanoparticles were produced by chemical vapor synthesis using tetraethylorthosilicate (TEOS) and subsequently decorated using two different gas-phase evaporative techniques. Both evaporative processes resulted in gold decoration of the silica particles. This study compares the mechanisms of particle decoration for a production method in which the gas and particles remain cool to a method in which the entire aerosol is heated. Results of transmission electron microscopy and visible spectroscopy studies indicate that both methods produce particles with similar morphologies and nearly identical absorption spectra, with peak absorption at 500-550 nm. A study of the thermal stability of the particles using heated-TEM indicates that the gold decoration on the particle surface remains stable at temperatures below 900 °C, above which the gold decoration begins to both evaporate and coalesce.

Nanoparticle enhanced thermal therapies

Thermal therapies such as hyperthermia, radiofrequency ablation, cryoablation, etc. have shown great potential and are gaining increasing clinical acceptance in the treatment of solid tumors. However, these treatment modalities are limited by the size of tumor that can be treated, incomplete tumor kill, and damage to adjacent normal tissues. To address these limitations, the concept of adjuvant-assisted thermal therapies has been proposed and tested to enhance the tumor destructive effects of thermal therapies. CYT-6091, a pegylated colloidal gold nanoparticle containing TNF-alpha bound to its surface, has been extensively investigated in our lab as an adjuvant to enhance thermal therapies. This paper describes our investigations of nanoparticle enhanced thermal therapies in various preclinical and translational models of solid tumors.