Detecting and treating cancer with nanotechnology

Biogenic green metal nano systems as efficient anti-cancer agents

Metal/metal oxide nano systems (M-NSs) of tunable and manipulative properties are emerging suitable for cancer management via immunity development, early-stage diagnosis, nanotherapeutics, and targeted drug delivery systems. However, noticeable toxicity, off-targeted actions, lacking biocompatibility, and being expensive limit their acceptability. Moreover, involving high energy (top-down routes) and hazardous chemicals (bottom-up chemical routes) is altering human cycle. To manage such challenges, biomass (plants, microbes, animals) and green chemistry-based M-NSs due to scalability, affordability, are cellular, tissue, and organ acceptability are emerging as desired biogenic M-NSs for cancer management with enhanced features. The state-of-art and perspective of green metal/metal oxide nano systems (GM-NSs) as an efficient anti-cancer agent including, imaging, immunity building elements, site-specific drug delivery, and therapeutics developments are highlighted in this review critically. It is expected that this report will serve as guideline for design and develop high-performance GM-NSs for establishing them as next-generation anti-cancer agent capable to manage cancer in personalized manner.

An Investigation of the Resonant and Non-Resonant Angular Time Delay of e-C60 Elastic Scattering

Time delay in electron scattering depends on both the scattering angle θ and scattered electron energy E. A study on the angular time delay of e-C60 elastic scattering was carried out in the present work. We employed the annular square well (ASW) potential to simulate the C60 environment. The contribution from different partial waves to the total angular time delay profile was examined in detail. The investigation was performed for both resonant and non-resonant energies, and salient characteristics in the time delay profile for each case were studied.

Noninvasive Biomarkers of Colorectal Cancer: Role in Diagnosis and Personalised Treatment Perspectives

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. It has been estimated that more than one-third of patients are diagnosed when CRC has already spread to the lymph nodes. One out of five patients is diagnosed with metastatic CRC. The stage of diagnosis influences treatment outcome and survival. Notwithstanding the recent advances in multidisciplinary management and treatment of CRC, patients are still reluctant to undergo screening tests because of the associated invasiveness and discomfort (e.g., colonoscopy with biopsies). Moreover, the serological markers currently used for diagnosis are not reliable and, even if they were useful to detect disease recurrence after treatment, they are not always detected in patients with CRC (e.g., CEA). Recently, translational research in CRC has produced a wide spectrum of potential biomarkers that could be useful for diagnosis, treatment, and follow-up of these patients. The aim of this review is to provide an overview of the newer noninvasive or minimally invasive biomarkers of CRC. Here, we discuss imaging and biomolecular diagnostics ranging from their potential usefulness to obtain early and less-invasive diagnosis to their potential implementation in the development of a bespoke treatment of CRC.

Current applications and future prospects of nanomaterials in tumor therapy

Tumors are one of the most serious human diseases and cause numerous global deaths per year. In spite of many strategies applied in tumor therapy, such as radiation therapy, chemotherapy, surgery, and a combination of these treatments, tumors are still the foremost killer worldwide among human diseases, due to their specific limitations, such as multidrug resistance and side effects. Therefore, it is urgent and necessary to develop new strategies for tumor therapy. Recently, the fast development of nanoscience has paved the way for designing new strategies to treat tumors. Nanomaterials have shown great potential in tumor therapy, due to their unique properties, including passive targeting, hyperthermia effects, and tumor-specific inhibition. This review summarizes the recent progress using the innate antitumor properties of metallic and nonmetallic nanomaterials to treat tumors, and related challenges and prospects are discussed.

Extracellular mycosynthesis of silver nanoparticles and their microbicidal activity

Myconanotechnology, a combination of mycology and nanotechnology that deals with the synthesis of nanoparticles using fungi or their metabolites, has great potential in the area of agriculture owing to the high surface-to-volume ratio and excellent biomedical, electronic, mechanical and physicochemical properties of these myconanoparticles. Extracellular mycosynthesis of Aspergillus flavus (KF934407) silver nanoparticles (AgNPs) was performed, which were produced by redox reaction. Furthermore, the extracellular synthesised AgNPs were characterised by ultraviolet/visible spectrophotometry, differential light scattering (DLS) and transmission electron microscopy. The bactericidal and fungicidal actions of synthesised silver myconanoparticles (myco-AgNPs) were studied against pathogenic bacteria and fungi. The formulated myco-AgNPs were spherical in shape, with a size in the range of 50nm and DLS at an intensity of 107.8nm. The myco-AgNPs showed effective antimicrobial properties against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Trichoderma spp. at high concentrations. In conclusion, AgNPs have a prolonged microbicidal effect as a result of continuous release of Ag⁺ at sufficient concentrations. Thus, A. flavus-based myco-AgNPs have the potential to be used as a non-toxic and cheap antimicrobial agent against various pathogenic bacteria and fungi.

Noninvasive targeting delivery and in vivo magnetic resonance tracking method for live apoptotic cells in cerebral ischemia with functional Fe2O3 magnetic nanoparticles

Background

Apoptotic neuronal death is known as programmed cell death. Inhibition of this progression might contribute to a new treatment strategy. However, methods for in vivo detection of live apoptotic cells are in need to be developed and established.

Context and purpose

The purpose of this study is to develop a new method for in vivo brain imaging for live apoptotic lesions using magnetic resonance imaging (MRI). We focused on the specific accumulation of our recently developed functional magnetic nanoparticles (FMNPs) into apoptotic cells using a rat cerebral ischemia model. Sulphorhodamine B, fluorescent dye was linked to valylalanylaspartic acid fluoromethyl ketone as a pan-caspase inhibitor to form SR-FLIVO. SR-FLIVO was bound with FMNPs to develop SR-FLIVO-FMNP probe. Ischemic rat brains were scanned by 7T MRI before and after intravenous injection of SR-FLIVO-FMNP and the distribution was evaluated by subtraction images of T2* colored mapping. SR-FLIVO, intracellular FMNPs, and T2* reduction area were histologically analyzed. The distribution of SR-FLIVO-FMNP was evaluated by subtracting the T2* signal images and was significantly correlated with the histological findings by TUNEL staining.

Results

Our experimental results revealed several findings where our newly developed probe SR-FLIVO-FMNP was intravenously administered into ischemic rats and FLIVO expression was tracked and found in apoptotic cells in rat brains after cerebral ischemia. A remarkable T2* reduction within the ischemic lesion was recorded using MRI based SR-FLIVO-FMNP probe as a contrasting agent due to the specific probe accumulation in apoptotic cells whereas, no observation of T2* reduction within the non-ischemic lesion due to no probe accumulation in non-apoptotic cells. Histological analysis based on the correlation between FLIVO and TUNEL staining showed that almost all FLIVO-positive cells were positive for TUNEL staining. These findings suggest the possibility for establishment of in vivo targeting delivery methods to live apoptotic cells based on conjugation of magnetic and fluorescent dual functional probes.

Conclusion

A newly developed probe SR-FLIVO-FMNP might be considered as a useful probe for in vivo apoptotic detection, and FMNPs might be a strong platform for noninvasive imaging and targeting delivery.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0173-1) contains supplementary material, which is available to authorized users.

Recent achievements in colorectal cancer diagnostic and therapy by the use of nanoparticles

Colorectal cancer is a major public health issue, being the third most common cancer in men and the second in women. It is one of the leading causes of cancer deaths. Nanomedicine is an emerging field of interest, many of its aspects being linked to cancer research. Chemotherapy has a well-established role in colorectal cancer management, unfortunately being limited by inability to have a selective distribution, by multidrug resistance and adverse effects. Researches carried out in recent years about nanotechnologies aimed, among others, to resolve the issues mentioned above. Targeted and localized delivery of the chemotherapeutic drugs, using nanoparticles, with selective destruction of cancerous cells would minimize the toxicity on healthy tissues. Also, the use of nanomaterials as contrast agent could improve sensitivity and specificity of diagnosis. The purpose of this review is to highlight the recent achievements of cancer research by use of nanomaterials, in the idea of finding the ideal composite, capable to simultaneous diagnostic and treat cancer.

Antimicrobial and immunomodulatory efficacy of extracellularly synthesized silver and gold nanoparticles by a novel phosphate solubilizing fungus Bipolaris tetramera

Background

Particulates of nanometers size have occupied a significant area in the field of medicinal and agricultural purposes due to their large surface-to-volume ratio and exceptional physicochemical, electronic and mechanical properties. Myconanotechnology, an interface between mycology and nanotechnology is budding nowadays for nanoparticle-fabrication using fungus or its metabolites. In the present study, we have isolated and characterized a novel phosphate solubilizing fungus B. tetramera KF934408 from rhizospheric soil. This phosphatase releasing fungus was subjected to extracellular synthesis of metal nanoparticles by redox reaction.

Results

Silver (AgNPs) and gold nanoparticles (AuNPs) were characterized by dynamic light scattering and transmission electron microscopic analysis. The formulated AgNPs were irregular shaped with a size ranging between 54.78 nm to 73.49 nm whereas AuNPs were spherical or hexagonal, with a size of 58.4 and 261.73 nm, respectively. The nanoparticles were assessed for their antibacterial and antifungal efficacy. The results showed effective antimicrobial activity of AgNPs against Bacillus cereus, Staphylococcus aureus, Enterobacter aeroginosa and Trichoderma sp. at higher concentrations, however, AuNPs possessed only moderate antibacterial efficacy while they found no antifungal activity. Cytotoxicity analysis of nanoparticles on J774 and THP1 α cell lines revealed the dose dependence in case of AgNPs, while AuNPs were non-toxic at both low and high doses. Furthermore, significant elevation of intracellular ROS was observed after 4 h of incubation with both the nanoparticles. The capping of fungal proteins on the particulates might be involved in the activities demonstrated by these inert metal nanoparticles.

Conclusion

In conclusion, the findings showed that the metal nanoparticles synthesized by fungus B. tetramera could be used as an antimicrobial agents as well as cost effective and nontoxic immunomodulatory delivery vehicle.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-015-0391-y) contains supplementary material, which is available to authorized users.

Dawn of advanced molecular medicine: nanotechnological advancements in cancer imaging and therapy

Nanotechnology plays an increasingly important role not only in our everyday life (with all its benefits and dangers) but also in medicine. Nanoparticles are to date the most intriguing option to deliver high concentrations of agents specifically and directly to cancer cells; therefore, a wide variety of these nanomaterials has been developed and explored. These span the range from simple nanoagents to sophisticated smart devices for drug delivery or imaging. Nanomaterials usually provide a large surface area, allowing for decoration with a large amount of moieties on the surface for either additional functionalities or targeting. Besides using particles solely for imaging purposes, they can also carry as a payload a therapeutic agent. If both are combined within the same particle, a theranostic agent is created. The sophistication of highly developed nanotechnology targeting approaches provides a promising means for many clinical implementations and can provide improved applications for otherwise suboptimal formulations. In this review we will explore nanotechnology both for imaging and therapy to provide a general overview of the field and its impact on cancer imaging and therapy.

Magnetite nanoparticles inhibit tumor growth and upregulate the expression of p53/p16 in Ehrlich solid carcinoma bearing mice

Background

Magnetite nanoparticles (MNPs) have been widely used as contrast agents and have promising approaches in cancer treatment. In the present study we used Ehrlich solid carcinoma (ESC) bearing mice as a model to investigate MNPs antitumor activity, their effect on expression of p53 and p16 genes as an indicator for apoptotic induction in tumor tissues.

Method

MNPs coated with ascorbic acid (size: 25.0±5.0 nm) were synthesized by co-precipitation method and characterized. Ehrlich mice model were treated with MNPs using 60 mg/Kg day by day for 14 injections; intratumorally (IT) or intraperitoneally (IP). Tumor size, pathological changes and iron content in tumor and normal muscle tissues were assessed. We also assessed changes in expression levels of p53 and p16 genes in addition to p53 protein level by immunohistochemistry.

Results

Our results revealed that tumor growth was significantly reduced by IT and IP MNPs injection compared to untreated tumor. A significant increase in p53 and p16 mRNA expression was detected in Ehrlich solid tumors of IT and IP treated groups compared to untreated Ehrlich solid tumor. This increase was accompanied with increase in p53 protein expression. It is worth mentioning that no significant difference in expression of p53 and p16 could be detected between IT ESC and control group.

Conclusion

MNPs might be more effective in breast cancer treatment if injected intratumorally to be directed to the tumor tissues.

Plasmonic nanobubbles as tunable cellular probes for cancer theranostics

This review is focused on a novel cellular probe, the plasmonic nanobubble (PNB), which has the dynamically tunable and multiple functions of imaging, diagnosis, delivery, therapy and, ultimately, theranostics. The concept of theranostics was recently introduced in order to unite the clinically important stages of treatment, namely diagnosis, therapy and therapy guidance, into one single, rapid and highly accurate procedure. Cell level theranostics will have far-reaching implications for the treatment of cancer and other diseases at their earliest stages. PNBs were developed to support cell level theranostics as a new generation of on-demand tunable cellular probes. A PNB is a transient vapor nanobubble that is generated within nanoseconds around an overheated plasmonic nanoparticle with a short laser pulse. In the short term, we expect that PNB technology will be rapidly adaptable to clinical medicine, where the single cell resolution it provides will be critical for diagnosing incipient or residual disease and eliminating cancer cells, while leaving healthy cells intact. This review discusses mechanisms of plasmonic nanobubbles and their biomedical applications with the focus on cancer cell theranostics.

Modified Gadonanotubes as a promising novel MRI contrasting agent

Background and purpose of the study

Carbon nanotubes (CNTs) are emerging drug and imaging carrier systems which show significant versatility. One of the extraordinary characteristics of CNTs as Magnetic Resonance Imaging (MRI) contrasting agent is the extremely large proton relaxivities when loaded with gadolinium ion (Gd_n³⁺) clusters.

Methods

In this study equated Gd_n³⁺ clusters were loaded in the sidewall defects of oxidized multiwalled (MW) CNTs. The amount of loaded gadolinium ion into the MWCNTs was quantified by inductively coupled plasma (ICP) method. To improve water solubility and biocompatibility of the system, the complexes were functionalized using diamine-terminated oligomeric poly (ethylene glycol) via a thermal reaction method.

Results

Gd_n³⁺ loaded PEGylated oxidized CNTs (Gd_n³⁺@CNTs-PEG) is freely soluble in water and stable in phosphate buffer saline having particle size of about 200 nm. Transmission electron microscopy (TEM) images clearly showed formation of PEGylated CNTs. MRI analysis showed that the prepared solution represents 10% more signal intensity even in half concentration of Gd³⁺ in comparison with commerciality available contrasting agent Magnevist®. In addition hydrophilic layer of PEG at the surface of CNTs could prepare stealth nanoparticles to escape RES.

Conclusion

It was shown that Gd_n³⁺@CNTs-PEG was capable to accumulate in tumors through enhanced permeability and retention effect. Moreover this system has a potential for early detection of diseases or tumors at the initial stages.

Drainage of cells and soluble antigen from the CNS to regional lymph nodes

Despite the absence of conventional lymphatics, there is efficient drainage of both cerebrospinal fluid (CSF) and interstitial fluid (ISF) from the CNS to regional lymph nodes. CSF drains from the subarachnoid space by channels that pass through the cribriform plate of the ethmoid bone to the nasal mucosa and cervical lymph nodes in animals and in humans; antigen presenting cells (APC) migrate along this pathway to lymph nodes. ISF and solutes drain from the brain parenchyma to cervical lymph nodes by a separate route along 100–150 nm wide basement membranes in the walls of cerebral capillaries and arteries. This pathway is too narrow for the migration of APC so it is unlikely that APC traffic directly from brain parenchyma to lymph nodes by this route. We present a model for the pivotal involvement of regional lymph nodes in immunological reactions of the CNS. The role of regional lymph nodes in immune reactions of the CNS in virus infections, the remote influence of the gut microbiota, multiple sclerosis and stroke are discussed. Evidence is presented for the role of cervical lymph nodes in the induction of tolerance and its influence on neuroimmunological reactions. We look to the future by examining how nanoparticle technology will enhance our understanding of CNS-lymph node connections and by reviewing the implications of lymphatic drainage of the brain for diagnosis and therapy of diseases of the CNS ranging from neuroimmunological disorders to dementias. Finally, we review the challenges and opportunities for progress in CNS-lymph node interactions and their involvement in disease processes.

STUDY OF THE NEAR INFRARED-MEDIATED HEATING OF DISPERSIONS OF PROTEIN-COATED PRISTINE AND CARBOXYLATED SINGLE-WALLED CARBON NANOTUBES

Previously, we demonstrated the selective NIR-mediated ablation of tumor cells in vitro using pristine single-walled carbon nanotubes (SWNTs) with adsorbed tumor-targeting ligands and carboxylated SWNTs with covalently-attached ligands. The covalent approach is advantageous in ensuring that protein ligands remain associated with the NIR-absorbing SWNTs in biological matrices and the noncovalent approach has the advantage of enabling SWNT functionalization without perturbation of the SWNT lattice and photothermal properties. Herein, we compare the ability of moderately-carboxylated (~4 at.% carboxylic acid groups) and pristine SWNT materials to absorb 808 nm radiation and convert it to heat. Under conditions of a constant 808 nm laser power density, the approach involved measuring the temperature of aqueous dispersions of protein-coated SWNTs as a function of the irradiation time. Nearly identical temperature profiles were observed for dispersions of moderately-carboxylated and pristine SWNTs possessing matched 808 nm optical densities and equivalent concentrations of carbonaceous species (i.e., SWNTs and amorphous carbon impurities). The results indicate that the amount of carbonaceous species in purified dispersions of protein-coated SWNTs is more important for converting absorbed 808 nm radiation into heat than whether or not the SWNTs were moderately carboxylated, and that moderately-carboxylated SWNTs could be the SWNT-material of choice for the targeted photothermal ablation of tumor cells.

Gold nanoparticles in theranostic oncology: current state-of-the-art

INTRODUCTION

In recent years, extensive multidisciplinary investigations have been carried out in the area of cancer nanotechnology. Gold nanoparticles (GNPs) have emerged as promising carrier for delivery of various pay-loads into their target. In view of their unique physicochemical and optical properties, GNPs have been exploited for multimodality imaging, tumor targeting, and as transporter of various therapeutics. Additionally, GNPs have been used as photothermal therapeutics against cancer.

AREAS COVERED

This review will focus on recent progress in the field of gold nanomaterials in cancer therapy and diagnosis. Moreover, concern about the toxicity of gold nanomaterials is addressed.

EXPERT OPINION

GNPs present versatile scaffolds for efficient delivery of cancer chemotherapeutics. Tuneable chemistry of the GNPs contributes to their ever increasing use in oncology research. The promises of a functional cancer therapy using GNPs have been extensively demonstrated, although the materials are still in their infancy stage and not surfaced to meet clinical standards.

Filter-based method for background removal in high-sensitivity wide-field-surface-enhanced Raman scattering imaging in vivo

As molecular imaging moves towards lower detection limits, the elimination of endogenous background signals becomes imperative. We present a facile background-suppression technique that specifically segregates the signal from surface-enhanced Raman scattering (SERS)-active nanoparticles (NPs) from the tissue autofluorescence background in vivo. SERS NPs have extremely narrow spectral peaks that do not overlap significantly with endogenous Raman signals. This can be exploited, using specific narrow-band filters, to image picomolar (pM) concentrations of NPs against a broad tissue autofluorescence background in wide-field mode, with short integration times that compare favorably with point-by-point mapping typically used in SERS imaging. This advance will facilitate the potential applications of SERS NPs as contrast agents in wide-field multiplexed biomarker-targeted imaging in vivo.

Cell Internalization Studies of Gadofullerene-(ZME-018) Immunoconjugates into A375m Melanoma Cells

Fullerene (C(60))-monoclonal antibody (mAb) immunoconjugates have been determined to internalize into target cells using water-soluble Gd(3+) ion-filled metallofullerenes (Gd@C(60)[OH](x)). Two separate conjugations of Gd@C(60)(OH)(x) with the antibody ZME-018 and a murine antibody mixture (MuIgG) were performed in a 1:5 mAb/Gd@C(60) ratio. Characterization of the immunoconjugates was established using inductively coupled plasma mass spectrometry (ICP-MS) for Gd(3+) and UV-Vis spectrometry (for Gd@C(60) + C(60)). Once conjugated, enzyme-linked immunosorbent assays showed little change in the specific binding of ZME-018. Each immunoconjugate was exposed to two cancer cell lines, A375m (antigen positive), and T24, bladder carcinoma (antigen negative). Internalization levels of the immunoconjugate were determined at various time points during 24 hours by harvesting and digesting the cells with 70% HNO(3) for Gd(3+) ion analysis by ICP-MS. These results are the first to demonstrate the practicality of a targeted cancer therapy based on fullerene immunotherapy.

'Click' synthesis of dextran macrostructures for combinatorial-designed self-assembled nanoparticles encapsulating diverse anticancer therapeutics

With the non-specific toxicity of anticancer drugs to healthy tissues upon systemic administration, formulations capable of enhanced selectivity in delivery to the tumor mass and cells are highly desirable. Based on the diversity of the drug payloads, we have investigated a combinatorial-designed strategy where the nano-sized formulations are tailored based on the physicochemical properties of the drug and the delivery needs. Individually functionalized C(2) to C(12) lipid-, thiol-, and poly(ethylene glycol) (PEG)-modified dextran derivatives were synthesized via 'click' chemistry from O-pentynyl dextran and relevant azides. These functionalized dextrans in combination with anticancer drugs form nanoparticles by self-assembling in aqueous medium having PEG surface functionalization and intermolecular disulfide bonds. Using anticancer drugs with logP values ranging from -0.5 to 3.0, the optimized nanoparticles formulations were evaluated for preliminary cellular delivery and cytotoxic effects in SKOV3 human ovarian adenocarcinoma cells. The results show that with the appropriate selection of lipid-modified dextran, one can effectively tailor the self-assembled nano-formulation for intended therapeutic payload.

Multifunctional nanoemulsion platform for imaging guided therapy evaluated in experimental cancer

Nanoparticle applications in medicine have seen a tremendous growth in the past decade. In addition to their drug targeting application and their ability to improve bioavailability of drugs, nanoparticles can be designed to allow their detection with a variety of imaging methodologies. In the current study, we developed a multimodal nanoparticle platform to enable imaging guided therapy, which was evaluated in a colon cancer mouse model. This "theranostic" platform is based on oil-in-water nanoemulsions and carries iron oxide nanocrystals for MRI, the fluorescent dye Cy7 for NIRF imaging, and the hydrophobic glucocorticoid prednisolone acetate valerate (PAV) for therapeutic purposes. Angiogenesis-targeted nanoemulsions functionalized with αvβ(3)-specific RGD peptides were evaluated, as well. When subcutaneous tumors were palpable, the nanoemulsions were administered at a dose of 30 mg of FeO/kg and 10 mg of PAV/kg. MRI and NIRF imaging showed significant nanoparticle accumulation in the tumors, while tumor growth profiles revealed a potent inhibitory effect in all of the PAV nanoemulsion-treated animals as compared to the ones treated with control nanoemulsions, the free drug, or saline. This study demonstrated that our nanoemulsions, when loaded with PAV, iron oxide nanocrystals, and Cy7, represent a flexible and unique theranostic nanoparticle platform that can be applied for imaging guided therapy of cancer.

Gadonanotubes as magnetic nanolabels for stem cell detection

Stem cell-based therapies have emerged as a promising approach in regenerative medicine. In the development of such therapies, the demand for imaging technologies that permit the noninvasive monitoring of transplanted stem cells in vivo is growing. Here, we report the performance of gadolinium-containing carbon nanocapsules, or gadonanotubes (GNTs), as a new T₁-weighted magnetic resonance imaging (MRI) intracellular labeling agent for pig bone marrow-derived mesenchymal stem cells (MSCs). Without the use of a transfection agent, micromolar concentrations of GNTs can deliver up to 10⁹ Gd(3+) ions per cell without compromising cell viability, differentiation potential, proliferation pattern, and phenotype. Imaging 10 × 10⁶ GNT-labeled MSCs demonstrates a nearly two-fold reduction in T₁ relaxation time when compared to unlabeled MSCs at 1.5 T in a clinical MRI scanner, which easily permits the discrimination of GNT-labeled MSCs in a T₁-weighted MR image. It is anticipated that GNTs will allow in vivo tracking of GNT-labeled MSCs, as well as other mammalian cell types, by T₁-weighted imaging with greater efficacy than other current technologies now allow.

Novel multifunctional nanoparticle mediates siRNA tumour delivery, visualisation and therapeutic tumour reduction in vivo

RNA interference (RNAi) is being widely explored as a means of tumour therapy due to the specific and potent silencing of targeted genes. However, in vivo delivery of RNAi effectors, such as small interfering RNA (siRNA) and detection of delivery is fraught with problems. Here, we describe novel theranostic PEGylated siRNA nanoparticles termed liposome-entrapped siRNA (LEsiRNA) nanoparticles. Our LEsiRNA nanoparticles are MR sensitive, contain labels for fluorescence microscopy/histology and promote functional siRNA delivery to tumours in mice leading to a significant reduction in both Survivin expression and tumour growth. LEsiRNA nanoparticles, administered by intravenous injection, were shown to accumulate in xenograft tumours by MR contrast image enhancements 24h post-administration. Fluorescence microscopy was used to corroborate the MR results and simultaneously demonstrate co-localisation of nanoparticles and siRNA within the tumours. The LEsiRNA nanoparticle-mediated delivery of the anti-cancer Survivin siRNA causes significant reduction in tumour growth when compared to controls. Our results suggest that LEsiRNA nanoparticles can be valuable as an in vivo delivery agent for siRNA therapy to tumours.

Magnetic nanoparticle hyperthermia for prostate cancer

Magnetic nanoparticles are increasingly used for clinical applications such as drug delivery, magnetic resonance imaging and magnetic fluid hyperthermia. A novel method of interstitial heating of tumours following direct injection of magnetic nanoparticles has been evaluated in humans in recent clinical trials. In prostate cancer this approach has been investigated in two separate phase I studies, employing magnetic nanoparticle thermotherapy alone and in combination with permanent seed brachytherapy. The feasibility and good tolerability was shown in both trials, using the first prototype of an alternating magnetic field applicator. As with any other heating technique, this novel approach requires specific tools for planning, quality control and thermal monitoring, based on appropriate imaging and modelling techniques. In these first clinical trials a newly developed method for planning and non-invasive calculations of the 3-dimensional temperature distribution based on computed tomography was validated. Limiting factors of the new approach at present are patient discomfort at high magnetic field strengths and irregular intratumoural heat distribution. Until these limitations are overcome and thermoablation can safely be applied as a monotherapy, this treatment modality is being evaluated in combination with irradiation in patients with localised prostate cancer.

The in vivo performance of plasmonic nanobubbles as cell theranostic agents in zebrafish hosting prostate cancer xenografts

Cell theranostics is a new approach that unites diagnosis, therapy and confirmation (guidance) of the results of therapy in one single process at cell level, thus principally improving both the rapidity and precision of treatment. The ideal theranostic agent will support all three of the above functions in vivo with cellular resolution, allowing individual assessment of disease state and the elimination of diseased cells while leaving healthy cells intact. We have developed and evaluated plasmonic nanobubbles (PNBs) as an in vivo tunable theranostic cellular agent in zebrafish hosting prostate cancer xenografts. PNBs were selectively generated around gold nanoparticles in cancer cells in the zebrafish with short single laser pulses. By varying the energy of the laser pulse, we dynamically tuned the PNB size in a theranostic sequence of two PNBs: an initial small PNB detected a cancer cell through optical scattering, followed by a second bigger PNB, which mechanically ablated this cell without damage to surrounding tissue, while its optical scattering confirmed the destruction of the cell. Thus PNBs supported the diagnosis and guided ablation of individual human cancer cells in a living organism without damage to the host.

What is cancer nanotechnology?

Cancer nanotechnology has the potential to dramatically improve current approaches to cancer detection, diagnosis, imaging, and therapy while reducing toxicity associated with traditional cancer therapy (1, 2). In this overview, we will define cancer nanotechnology, consider issues related to application of nanotechnology for cancer imaging and therapy, and broadly consider implications for continued development in nanotechnology for the future of clinical cancer care. These considerations will place in perspective the methodological approaches in cancer nanotechnology and subject reviews outlined in this volume.

Aluminum nanoparticles enhance anticancer immune response induced by tumor cell vaccine

The application of nanomaterial in cancer treatment is promising and intriguing. Anti-tumor immunotherapy has the potential to significantly improve the prognosis of cancer treatment, though the efficacy of immunotherapy generally needs further improvement. One way to improve the efficacy is using immune adjuvants, but the adjuvants for anticancer immunotherapy have to be more potent than for prophylactic vaccines. Here, we report that compared to conventional alum adjuvant, aluminum oxide nanoparticles (nano-alum) may further enhance the anticancer effects of an immunotherapy that employs tumor cell vaccine (TCV). The average tumor size tends to be lower in animals that receive the combinational treatment of nano-alum and TCV. The anticancer cytotoxicity by the lymphocytes was also significantly higher in the treatment group that received both TCV and nano-alum. These results suggest that nano-alum may potentially serve as a potent immune adjuvant and have prospective applications in anticancer immunotherapy.

Conscripts of the infinite armada: systemic cancer therapy using nanomaterials

The field of clinical nanomaterials is enlarging steadily, with more than a billion US dollars of funding allocated to research by US government agencies in the past decade. The first generation of anti-cancer agents using novel nanomaterials has successfully entered widespread use. Newer nanomaterials are garnering increasing interest as potential multifunctional therapeutic agents; these drugs are conferred novel properties, by virtue of their size and shape. The new features of these agents could potentially allow increased cancer selectivity, changes in pharmacokinetics, amplification of cytotoxic effects, and simultaneous imaging capabilities. After attachment to cancer target reactive-ligands, which interact with cell-surface antigens or receptors, these new constructs can deliver cytolytic and imaging payloads. The molecules also introduce new challenges for drug development. While nanoscale molecules are of a similar size to proteins, the paradigms for how cells, tissues and organs of the body react to the non-biological materials are not well understood, because most cellular and metabolic processes have evolved to deal with globular, enzyme degradable molecules. We discuss examples of different materials to illustrate interesting principles for development and future applications of these nanomaterial medicines with emphasis on the possible pharmacologic and safety hurdles for accomplishing therapeutic goals.

In vivo behavior of large doses of ultrashort and full-length single-walled carbon nanotubes after oral and intraperitoneal administration to Swiss mice

Carbon nanotube (CNT) materials are of special interest as potential tools for biomedical applications. However, available toxicological data concerning single-walled carbon nanotubes (SWNTs) and multiwalled carbon nanotubes (MWNTs) remain contradictory. Here, we compared the effects of SWNTs as a function of dose, length, and surface chemistry in Swiss mice. Transmission electron microscopy (TEM), Raman, near-infrared (NIR), and X-ray photoelectron spectroscopies have been used to characterize the tested materials. The dose of SWNT materials used in this study is considerably higher than that proposed for most biomedical applications, but it was deemed necessary to administer such large doses to accurately assess the toxicological impact of the materials. In an acute toxicity test, SWNTs were administered orally at a dose level of 1000 mg/kg bodyweight (b.w.). Neither death nor growth or behavioral troubles were observed. After intraperitoneal administration, SWNTs, irrespective of their length or dose (50-1000 mg/kg b.w.), can coalesce inside the body to form fiberlike structures. When structure lengths exceeded 10 mum, they irremediably induced granuloma formation. Smaller aggregates did not induce granuloma formation, but they persisted inside cells for up to 5 months after administration. Short (<300 nm) well-individualized SWNTs can escape the reticuloendothelial system to be excreted through the kidneys and bile ducts. These findings suggest that if the potential of SWNTs for medical applications is to be realized, they should be engineered into discrete, individual "molecule-like" species.

Targeted hyperthermia using metal nanoparticles

Despite the use of hyperthermia to treat cancer for thousands of years, the challenge of only heating malignant cells remains daunting. In pre-clinical and early clinical trials, metal nanoparticles induce hyperthermic cytotoxicity when exposed to near-infrared radiation or radiofrequency fields. We discuss the emerging roles of nanoparticles, especially gold, in the hyperthermic treatment of cancer. In addition, we discuss the similarities of radiofrequency ablation and nanoparticle mediated cytotoxicity.

Use of nanoparticles for targeted, noninvasive thermal destruction of malignant cells

Shortwave (MHz range) radiofrequency (RF) energy is nonionizing, penetrates deeply into biological tissues with no adverse side effects, and heats metallic nanoparticles efficiently. Targeted delivery of these nanoparticles to cancer cells should result in hyperthermic cytotoxicity upon exposure to a focused, noninvasive RF field. We have demonstrated that gold nanoparticles conjugated with cetuximab (C225) are quickly internalized by Panc-1 (pancreatic adenocarcinoma) and Difi (colorectal adenocarcinoma) cancer cells overexpressing epidermal growth factor receptor (EGFR). Panc-1 or Difi cells treated with naked gold nanoparticles or nonspecific IgG-conjugated gold nanoparticles demonstrated minimal intracellular uptake of gold nanoparticles by transmission electron microscopy (TEM). In contrast, there were dense concentrations of cytoplasmic vesicles containing gold nanoparticles following treatment with cetuximab-conjugated gold nanoparticles. Exposure of cells to a noninvasive RF field produced nearly 100% cytotoxicity in cells treated with the cetuximab-conjugated gold nanoparticles, but significantly lower levels of cytotoxicity in the two control groups (p < 0.00012). Treatment of a breast cancer cell line (CAMA-1) that does not express EGFR with cetuximab-conjugated gold nanoparticles produced no enhanced cytotoxicity following treatment in the RF field. Conjugation of cancer cell-directed targeting agents to gold nanoparticles may represent an effective and cancer-specific therapy to treat numerous types of human malignant disease using noninvasive RF hyperthermia.

Superparamagnetic iron oxide nanoparticles: diagnostic magnetic resonance imaging and potential therapeutic applications in neurooncology and central nervous system inflammatory pathologies, a review

Superparamagnetic iron oxide nanoparticles have diverse diagnostic and potential therapeutic applications in the central nervous system (CNS). They are useful as magnetic resonance imaging (MRI) contrast agents to evaluate: areas of blood-brain barrier (BBB) dysfunction related to tumors and other neuroinflammatory pathologies, the cerebrovasculature using perfusion-weighted MRI sequences, and in vivo cellular tracking in CNS disease or injury. Novel, targeted, nanoparticle synthesis strategies will allow for a rapidly expanding range of applications in patients with brain tumors, cerebral ischemia or stroke, carotid atherosclerosis, multiple sclerosis, traumatic brain injury, and epilepsy. These strategies may ultimately improve disease detection, therapeutic monitoring, and treatment efficacy especially in the context of antiangiogenic chemotherapy and antiinflammatory medications. The purpose of this review is to outline the current status of superparamagnetic iron oxide nanoparticles in the context of biomedical nanotechnology as they apply to diagnostic MRI and potential therapeutic applications in neurooncology and other CNS inflammatory conditions.

Facile preparation of a new gadofullerene-based magnetic resonance imaging contrast agent with high 1H relaxivity

A new magnetic resonance imaging (MRI) contrast agent based on the trimetallic nitride templated (TNT) metallofullerene Gd(3)N@C(80) was synthesized by a facile method in high yield. The observed longitudinal and transverse relaxivities r(1) and r(2) for water hydrogens in the presence of the water-soluble gadofullerene 2 Gd(3)N@C(80)(OH)(approximately 26)(CH(2)CH(2)COOM)(approximately 16) (M = Na or H) are 207 and 282 mM(-1) s(-1) (per C(80) cage) at 2.4 T, respectively; these values are 50 times larger than those of Gd(3+) poly(aminocarboxylate) complexes, such as commercial Omniscan and Magnevist. This high (1)H relaxivity for this new hydroxylated and carboxylated gadofullerene derivative provides high signal enhancement at significantly lower Gd concentration as demonstrated by in vitro and in vivo MRI studies. Dynamic light scattering data reveal a unimodal size distribution with an average hydrodynamic radius of ca. 78 nm in pure water (pH = 7), which is significantly different from other hydroxylated or carboxylated fullerene and metallofullerene derivatives reported to date. Agarose gel infusion results indicate that the gadofullerene 2 displayed diffusion properties different from those of commercial Omniscan and those of PEG5000 modified Gd(3)N@C(80). The reactive carboxyl functionality present on this highly efficient contrast agent may also serve as a precursor for biomarker tissue-targeting purposes.

Multiplexed imaging of surface enhanced Raman scattering nanotags in living mice using noninvasive Raman spectroscopy

Raman spectroscopy is a newly developed, noninvasive preclinical imaging technique that offers picomolar sensitivity and multiplexing capabilities to the field of molecular imaging. In this study, we demonstrate the ability of Raman spectroscopy to separate the spectral fingerprints of up to 10 different types of surface enhanced Raman scattering (SERS) nanoparticles in a living mouse after s.c. injection. Based on these spectral results, we simultaneously injected the five most intense and spectrally unique SERS nanoparticles i.v. to image their natural accumulation in the liver. All five types of SERS nanoparticles were successfully identified and spectrally separated using our optimized noninvasive Raman imaging system. In addition, we were able to linearly correlate Raman signal with SERS concentration after injecting four spectrally unique SERS nanoparticles either s.c. (R(2) = 0.998) or i.v. (R(2) = 0.992). These results show great potential for multiplexed imaging in living subjects in cases in which several targeted SERS probes could offer better detection of multiple biomarkers associated with a specific disease.

Translational nanomedicine: status assessment and opportunities

Nano-enabled technologies hold great promise for medicine and health. The rapid progress by the physical sciences/engineering communities in synthesizing nanostructures and characterizing their properties must be rapidly exploited in medicine and health toward reducing mortality rate, morbidity an illness imposes on a patient, disease prevalence, and general societal burden. A National Science Foundation-funded workshop, "Re-Engineering Basic and Clinical Research to Catalyze Translational Nanoscience," was held 16-19 March 2008 at the University of Southern California. Based on that workshop and literature review, this article briefly explores scientific, economic, and societal drivers for nanomedicine initiatives; examines the science, engineering, and medical research needs; succinctly reviews the US federal investment directly germane to medicine and health, with brief mention of the European Union (EU) effort; and presents recommendations to accelerate the translation of nano-enabled technologies from laboratory discovery into clinical practice.

FROM THE CLINICAL EDITOR

An excellent review paper based on the NSF funded workshop "Re-Engineering Basic and Clinical Research to Catalyze Translational Nanoscience" (16-19 March 2008) and extensive literature search, this paper briefly explores the current state and future perspectives of nanomedicine.

Clinical applications of magnetic nanoparticles for hyperthermia

Magnetic fluids are increasingly used for clinical applications such as drug delivery, magnetic resonance imaging and magnetic fluid hyperthermia. The latter technique that has been developed as a cancer treatment for several decades comprises the injection of magnetic nanoparticles into tumors and their subsequent heating in an alternating magnetic field. Depending on the applied temperature and the duration of heating this treatment either results in direct tumor cell killing or makes the cells more susceptible to concomitant radio- or chemotherapy. Numerous groups are working in this field worldwide, but only one approach has been tested in clinical trials so far. Here, we summarize the clinical data gained in these studies on magnetic fluid induced hyperthermia.

Significant redistribution of Ce 4d oscillator strength observed in photoionization of endohedral Ce@C82+ ions

Mass-selected beams of atomic Ceq+ ions (q = 2, 3, 4), of C82+ and of endohedral Ce@C82+ ions were employed to study photoionization of free and encaged cerium atoms. The Ce 4d inner-shell contributions to single and double ionization of the endohedral Ce@C82+ fullerene have been extracted from the data and compared with expectations based on theory and the experiments with atomic Ce ions. Dramatic reduction and redistribution of the ionization contributions to 4d photoabsorption is observed. More than half of the Ce 4d oscillator strength appears to be diverted to the additional decay channels opened by the fullerene cage surrounding the Ce atom.