Treating metastatic cancer with nanotechnology

Ultrasensitive, Biocompatible, Self-Calibrating, Multiparametric Temperature Sensors

Core-shell quantum dots serve as self-calibrating, ultrasensitive, multiparametric, near-infrared, and biocompatible temperature sensors. They allow temperature measurement with nanometer accuracy in the range 150-373 K, the broadest ever recorded for a nanothermometer, with sensitivities among the highest ever reported, which makes them essentially unique in the panorama of biocompatible nanothermometers with potential for in vivo biological thermal imaging and/or thermoablative therapy.

Abnormalities in Alternative Splicing of Apoptotic Genes and Cardiovascular Diseases

Apoptosis is required for normal heart development in the embryo, but has also been shown to be an important factor in the occurrence of heart disease. Alternative splicing of apoptotic genes is currently emerging as a diagnostic and therapeutic target for heart disease. This review addresses the involvement of abnormalities in alternative splicing of apoptotic genes in cardiac disorders including cardiomyopathy, myocardial ischemia and heart failure. Many pro-apoptotic members of the Bcl-2 family have alternatively spliced isoforms that lack important active domains. These isoforms can play a negative regulatory role by binding to and inhibiting the pro-apoptotic forms. Alternative splicing is observed to be increased in various cardiovascular diseases with the level of alternate transcripts increasing elevated in diseased hearts compared to healthy subjects. In many cases these isoforms appear to be the underlying cause of the disease, while in others they may be induced in response to cardiovascular pathologies. Regardless of this, the detection of alternate splicing events in the heart can serve as useful diagnostic or prognostic tools, while those splicing events that seem to play a causative role in cardiovascular disease make attractive future drug targets.

Glyconanomaterials for Combating Bacterial Infections

Bacterial infections constitute an increasing problem to human health in response to build-up of resistance to present antibiotics and sluggish development of new pharmaceuticals. However, a means to address this problem is to pinpoint the drug delivery to-and into-the bacteria. This results in a high local concentration of the drug, circumventing the increasingly high doses otherwise necessary. Combined with other effectors, such as covalent attachment to carriers, rendering the drugs less degradable, and the combination with efflux inhibitors, old drugs can be revived. In this context, glyconanomaterials offer exceptional potential, since these materials can be tailored to accommodate different effectors. In this Concept article, we describe the different advantages of glyconanomaterials, and point to their potential in antibiotic "revitalization".

Microfluidics-based single-step preparation of injection-ready polymeric nanosystems for medical imaging and drug delivery

Translation of therapeutic polymeric nanosystems to patients and industry requires simplified, reproducible and scalable methods for assembly and loading. A single-step in-line process based on nanocoprecipitation of oxazoline-siloxane block copolymers in flow-focusing poly(dimethylsiloxane) microfluidics was designed to manufacture injection-ready nanosystems. Nanosystem characteristics could be controlled by copolymer concentration, block length and chemistry, microchannel geometry, flow rate, aqueous/organic flow rate ratio and payload concentration. The well-tolerated nanosystems exhibited differential cell binding and payload delivery and could confer sensitivity to photodynamic therapy to HeLa cancer cells. Such injection-ready nanosystems carrying drugs, diagnostic or functional materials may facilitate translation to clinical application.

Double loaded self-decomposable SiO₂ nanoparticles for sustained drug release

Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms-the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood circulation with a Tmax of about 8 h, afterwards a long lasting release pattern was achieved to maintain drug systemic exposure with a plasma elimination half-life of approximately 28 h. We disclosed that the absorbed drug molecules contributed to the initial fast release for quickly reaching the therapeutic level with relatively higher plasma concentrations, while the "grown-in" drugs were responsible for maintaining the therapeutic level via the later controlled slow and sustained release. The present nanoparticle carrier drug configuration and the loading/maintenance release mechanisms provide a promising platform that ensures a prolonged therapeutic effect by controlling drug concentrations within the therapeutic window-a sustained drug delivery system with a great impact on improving the management of chronic diseases.

Diagnosis of prostate cancer via nanotechnological approach

Prostate cancer is one of the leading causes of cancer-related deaths among the Caucasian adult males in Europe and the USA. Currently available diagnostic strategies for patients with prostate cancer are invasive and unpleasant and have poor accuracy. Many patients have been overly or underly treated resulting in a controversy regarding the reliability of current conventional diagnostic approaches. This review discusses the state-of-the-art research in the development of novel noninvasive prostate cancer diagnostics using nanotechnology coupled with suggested diagnostic strategies for their clinical implication.

Development of nanotheranostics against metastatic breast cancer--A focus on the biology & mechanistic approaches

Treatment for metastatic breast cancer still remains to be a challenge since the currently available diagnostic and treatment strategies fail to detect the micro-metastasis resulting in higher mortality rate. Moreover, the lack of specificity to target circulating tumor cells is also a factor. In addition, currently available imaging modalities to identify the secondaries vary with respect to various metastatic anatomic areas and size of the tumor. The drawbacks associated with the existing clinical management of the metastatic breast cancer demands the requirement of multifunctional nanotheranostics, which could diagnose at macro- and microscopic level, target the solid as well as circulating tumor cells and control further progression with the simultaneous evaluation of treatment response in a single platform. However, without the understanding of the biology as well as preferential homing ability of circulating tumor cells at distant organs, it is quite impossible to address the existing challenges in the present diagnostics and therapeutics against the breast cancer metastasis. Hence this review outlines the severity of the problem, basic biology and organ specificity with the sequential steps for the secondary progression of disease followed by the various mechanistic approaches in diagnosis and therapy at different stages.

Polymer nanoassemblies with solvato- and halo-fluorochromism for drug release monitoring and metastasis imaging

BACKGROUND

Theranostics, an emerging technique that combines therapeutic and diagnostic modalities for various diseases, holds promise to detect cancer in early stages, eradicate metastatic tumors and ultimately reduce cancer mortality.

METHODS & RESULTS

This study reports unique polymer nanoassemblies that increase fluorescence intensity upon addition of hydrophobic drugs and either increase or decrease fluorescence intensity in acidic environments, depending on nanoparticle core environment properties. Extensive spectroscopic analyses were performed to determine optimal excitation and emission wavelengths, which enabled real time measurement of drugs releasing from the nanoassemblies and ex vivo imaging of acidic liver metastatic tumors from mice.

CONCLUSION

Polymer nanoassemblies with solvato- and halo-fluorochromic properties are promising platforms to develop novel theranostic tools for the detection and treatment of metastatic tumors.

89 Zr- and Fe-Labeled Polymeric Micelles for Dual Modality PET and T1 -Weighted MR Imaging

In this study, a new ⁸⁹ Zr- and Fe³⁺ -labeled micelle nanoplatform (⁸⁹ Zr/Fe-DFO-micelles) for dual modality position emission tomography/magnetic resonance (PET/MR) imaging is investigated. The nanoplatform consists of self-assembling amphiphilic diblock copolymers that are functionalized with ⁸⁹ Zr-deferoxamine (⁸⁹ Zr-DFO) and Fe³⁺ -deferoxamine (Fe-DFO) for PET and MR purposes, respectively. ⁸⁹ Zr displays favorable PET imaging characteristics with a 3.3 d half-life suitable for imaging long circulating nanoparticles. The nanoparticles are modified with Fe-DFO as MR T₁ -contrast label instead of commonly used Gd³⁺ -based chelates. As these micelles are cleared by liver and spleen, any long term Gd- related toxicity such as nephrogenic systemic fibrosis is avoided. As a proof of concept, an in vivo PET/MR study in mice is presented showing tumor targeting of ⁸⁹ Zr/Fe-DFO-micelles through the enhanced permeability and retention (EPR) effect of tumors, yielding high tumor-to-blood (10.3 ± 3.6) and tumor-to-muscle (15.3 ± 8.1) ratios at 48 h post injection. In vivo PET images clearly delineate the tumor tissue and show good correspondence with ex vivo biodistribution results. In vivo magnetic resonance imaging (MRI) allows visualization of the intratumoral distribution of the ⁸⁹ Zr/Fe-DFO-micelles at high resolution. In summary, the ⁸⁹ Zr/Fe-DFO-micelle nanoparticulate platform allows EPR-based tumor PET/MRI, and, furthermore, holds great potential for PET/MR image guided drug delivery.

On/off-switchable anti-neoplastic nanoarchitecture

Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO₂ Pops) nanoarchitecture. The resulting TiO₂ Pops, unlike TiO₂ nanoparticles (TiO₂ NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO₂ Pops show very high photocatalytic activity compared to TiO₂ NPs. Upon on/off-switchable photo activation, the TiO₂ Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the ‘death gate’, thus reducing the survival of cancer cells by at least six times in comparison with TiO₂ NPs without affecting the normal cells.

Mathematical framework for activity-based cancer biomarkers

Advances in nanomedicine are providing sophisticated functions to precisely control the behavior of nanoscale drugs and diagnostics. Strategies that coopt protease activity as molecular triggers are increasingly important in nanoparticle design, yet the pharmacokinetics of these systems are challenging to understand without a quantitative framework to reveal nonintuitive associations. We describe a multicompartment mathematical model to predict strategies for ultrasensitive detection of cancer using synthetic biomarkers, a class of activity-based probes that amplify cancer-derived signals into urine as a noninvasive diagnostic. Using a model formulation made of a PEG core conjugated with protease-cleavable peptides, we explore a vast design space and identify guidelines for increasing sensitivity that depend on critical parameters such as enzyme kinetics, dosage, and probe stability. According to this model, synthetic biomarkers that circulate in stealth but then activate at sites of disease have the theoretical capacity to discriminate tumors as small as 5 mm in diameter-a threshold sensitivity that is otherwise challenging for medical imaging and blood biomarkers to achieve. This model may be adapted to describe the behavior of additional activity-based approaches to allow cross-platform comparisons, and to predict allometric scaling across species.

Reversal of multidrug resistance by co-delivery of paclitaxel and lonidamine using a TPGS and hyaluronic acid dual-functionalized liposome for cancer treatment

Multidrug resistance (MDR) remains the primary issue in cancer therapy, which is characterized by the overexpressed P-glycoprotein (P-gp)-included efflux pump or the upregulated anti-apoptotic proteins. In this study, a D-alpha-tocopheryl poly (ethylene glycol 1000) succinate (TPGS) and hyaluronic acid (HA) dual-functionalized cationic liposome containing a synthetic cationic lipid, 1,5-dioctadecyl-N-histidyl-L-glutamate (HG2C18) was developed for co-delivery of a small-molecule chemotherapeutic drug, paclitaxel (PTX) with a chemosensitizing agent, lonidamine (LND) to treat the MDR cancer. It was demonstrated that the HG2C18 lipid contributes to the endo-lysosomal escape of the liposome following internalization for efficient intracellular delivery. The TPGS component was confirmed able to elevate the intracellular accumulation of PTX by inhibiting the P-gp efflux, and to facilitate the mitochondrial-targeting of the liposome. The intracellularly released LND suppressed the intracellular ATP production by interfering with the mitochondrial function for enhanced P-gp inhibition, and additionally, sensitized the MDR breast cancer (MCF-7/MDR) cells to PTX for promoted induction of apoptosis through a synergistic effect. Functionalized with the outer HA shell, the liposome preferentially accumulated at the tumor site and showed a superior antitumor efficacy in the xenograft MCF-7/MDR tumor mice models. These findings suggest that this dual-functional liposome for co-delivery of a cytotoxic drug and an MDR modulator provides a promising strategy for reversal of MDR in cancer treatment.

Nanomedicine applied to translational oncology: A future perspective on cancer treatment

The high global incidence of cancer is associated with high rates of mortality and morbidity worldwide. By taking advantage of the properties of matter at the nanoscale, nanomedicine promises to develop innovative drugs with greater efficacy and less side effects than standard therapies. Here, we discuss both clinically available anti-cancer nanomedicines and those en route to future clinical application. The properties, therapeutic value, advantages and limitations of these nanomedicine products are highlighted, with a focus on their increased performance versus conventional molecular anticancer therapies. The main regulatory challenges toward the translation of innovative, clinically effective nanotherapeutics are discussed, with a view to improving current approaches to the clinical management of cancer. Ultimately, it becomes clear that the critical steps for clinical translation of nanotherapeutics require further interdisciplinary and international effort, where the whole stakeholder community is involved from bench to bedside. From the Clinical Editor: Cancer is a leading cause of mortality worldwide and finding a cure remains the holy-grail for many researchers and clinicians. The advance in nanotechnology has enabled novel strategies to develop in terms of cancer diagnosis and therapy. In this concise review article, the authors described current capabilities in this field and outlined comparisons with existing drugs. The difficulties in bringing new drugs to the clinics were also discussed.

Nano-Sized Drug Delivery Systems: Development and Implication in Treatment of Hepatocellular Carcinoma

Liver cancer results in enormous human toll worldwide. Over the years, various chemotherapeutic entities have been employed for treatment of advanced HCC; however, as of yet none embody attributes to improve overall survival. Following rapid advancement in nanotechnology, it is envisage that nanoscale systems may emerge as intriguing platforms to improve chemotherapeutic strategies against various cancers including liver cancer; with better insight in the understanding of pathophysiology of liver cancer and material science, the field of nanotechnology may bring newer hope to liver cancer treatment. Reckoning with these, we detailed the arsenal of nanoformulations that are in various stages of clinical development/ preclinical settings for the treatment of liver cancer together with providing a glimpse of the attributes of nanotechnology in revolutionizing the status of chemotherapeutic modalities.

Particle tracking in drug and gene delivery research: State-of-the-art applications and methods

Particle tracking is a powerful microscopy technique to quantify the motion of individual particles at high spatial and temporal resolution in complex fluids and biological specimens. Particle tracking's applications and impact in drug and gene delivery research have greatly increased during the last decade. Thanks to advances in hardware and software, this technique is now more accessible than ever, and can be reliably automated to enable rapid processing of large data sets, thereby further enhancing the role that particle tracking will play in drug and gene delivery studies in the future. We begin this review by discussing particle tracking-based advances in characterizing extracellular and cellular barriers to therapeutic nanoparticles and in characterizing nanoparticle size and stability. To facilitate wider adoption of the technique, we then present a user-friendly review of state-of-the-art automated particle tracking algorithms and methods of analysis. We conclude by reviewing technological developments for next-generation particle tracking methods, and we survey future research directions in drug and gene delivery where particle tracking may be useful.

Non-genetic engineering of cells for drug delivery and cell-based therapy

Cell-based therapy is a promising modality to address many unmet medical needs. In addition to genetic engineering, material-based, biochemical, and physical science-based approaches have emerged as novel approaches to modify cells. Non-genetic engineering of cells has been applied in delivering therapeutics to tissues, homing of cells to the bone marrow or inflammatory tissues, cancer imaging, immunotherapy, and remotely controlling cellular functions. This new strategy has unique advantages in disease therapy and is complementary to existing gene-based cell engineering approaches. A better understanding of cellular systems and different engineering methods will allow us to better exploit engineered cells in biomedicine. Here, we review non-genetic cell engineering techniques and applications of engineered cells, discuss the pros and cons of different methods, and provide our perspectives on future research directions.

Spatiotemporal Targeting of a Dual-Ligand Nanoparticle to Cancer Metastasis

Various targeting strategies and ligands have been employed to direct nanoparticles to tumors that upregulate specific cell-surface molecules. However, tumors display a dynamic, heterogeneous microenvironment, which undergoes spatiotemporal changes including the expression of targetable cell-surface biomarkers. Here, we investigated a dual-ligand nanoparticle to effectively target two receptors overexpressed in aggressive tumors. By using two different chemical specificities, the dual-ligand strategy considered the spatiotemporal alterations in the expression patterns of the receptors in cancer sites. As a case study, we used two mouse models of metastasis of triple-negative breast cancer using the MDA-MB-231 and 4T1 cells. The dual-ligand system utilized two peptides targeting P-selectin and αvβ3 integrin, which are functionally linked to different stages of the development of metastatic disease at a distal site. Using in vivo multimodal imaging and post mortem histological analyses, this study shows that the dual-ligand nanoparticle effectively targeted metastatic disease that was otherwise missed by single-ligand strategies. The dual-ligand nanoparticle was capable of capturing different metastatic sites within the same animal that overexpressed either receptor or both of them. Furthermore, the highly efficient targeting resulted in 22% of the injected dual-ligand nanoparticles being deposited in early-stage metastases within 2 h after injection.

Disulfide-Functionalized Unimolecular Micelles as Selective Redox-Responsive Nanocarriers

Redox-sensitive hyperbranched dendritic-linear polymers (HBDLPs) were prepared and stabilized individually as unimolecular micelles with diameters in the range 25-40 nm. The high molecular weight (500-950 kDa), core-shell amphiphilic structures were synthesized through a combination of self-condensing vinyl copolymerization (SCVCP) and atom transfer radical polymerization (ATRP). Cleavable disulfide bonds were introduced, either in the backbone, or in pendant groups, of the hyperbranched core of the HBDLPs. By triggered reductive degradation, the HBDLPs showed up to a 7-fold decrease in molecular weight, and the extent of degradation was tuned by the amount of incorporated disulfides. The HBDLP with pendant disulfide-linked functionalities in the hyperbranched core was readily postfunctionalized with a hydrophobic dye, as a mimic for a drug. An instant release of the dye was observed as a response to a reductive environment similar to the one present intracellularly. The proposed strategy shows a facile route to highly stable unimolecular micelles, which attractively exhibit redox-responsive degradation and cargo release properties.

A novel Trojan-horse targeting strategy to reduce the non-specific uptake of nanocarriers by non-cancerous cells

One big challenge with active targeting of nanocarriers is non-specific binding between targeting molecules and non-target moieties expressed on non-cancerous cells, which leads to non-specific uptake of nanocarriers by non-cancerous cells. Here, we propose a novel Trojan-horse targeting strategy to hide or expose the targeting molecules of nanocarriers on-demand. The non-specific uptake by non-cancerous cells can be reduced because the targeting molecules are hidden in hydrophilic polymers. The nanocarriers are still actively targetable to cancer cells because the targeting molecules can be exposed on-demand at tumor regions. Typically, Fe3O4 nanocrystals (FN) as magnetic resonance imaging (MRI) contrast agents were encapsulated into albumin nanoparticles (AN), and then folic acid (FA) and pH-sensitive polymers (PP) were grafted onto the surface of AN-FN to construct PP-FA-AN-FN nanoparticles. Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), transmission electron microscope (TEM) and gel permeation chromatography (GPC) results confirm successful construction of PP-FA-AN-FN. According to difference of nanoparticle-cellular uptake between pH 7.4 and 5.5, the weight ratio of conjugated PP to nanoparticle FA-AN-FN (i.e. graft density) and the molecular weight of PP (i.e. graft length) are optimized to be 1.32 and 5.7 kDa, respectively. In vitro studies confirm that the PP can hide ligand FA to prevent it from binding to cells with FRα at pH 7.4 and shrink to expose FA at pH 5.5. In vivo studies demonstrate that our Trojan-horse targeting strategy can reduce the non-specific uptake of the PP-FA-AN-FN by non-cancerous cells. Therefore, our PP-FA-AN-FN might be used as an accurately targeted MRI contrast agent.

Macrophage Cell Membrane Camouflaged Mesoporous Silica Nanocapsules for In Vivo Cancer Therapy

Engineering natural macrophage cell membrane-camouflaged mesoporous silica nanocapsules can reduce the arrested percentage of immune cells and tissues, effectively prolong the survival time of nanoparticles in blood circulation system, and improve the accumulation in tumor.

Vascular Targeting of a Gold Nanoparticle to Breast Cancer Metastasis

The vast majority of breast cancer deaths are due to metastatic disease. Although deep tissue targeting of nanoparticles is suitable for some primary tumors, vascular targeting may be a more attractive strategy for micrometastasis. This study combined a vascular targeting strategy with the enhanced targeting capabilities of a nanoparticle to evaluate the ability of a gold nanoparticle (AuNP) to specifically target the early spread of metastatic disease. As a ligand for the vascular targeting strategy, we utilized a peptide targeting alpha(v) beta(3) integrin, which is functionally linked to the development of micrometastases at a distal site. By employing a straightforward radiolabeling method to incorporate Technetium-99m into the AuNPs, we used the high sensitivity of radionuclide imaging to monitor the longitudinal accumulation of the nanoparticles in metastatic sites. Animal and histological studies showed that vascular targeting of the nanoparticle facilitated highly accurate targeting of micrometastasis in the 4T1 mouse model of breast cancer metastasis using radionuclide imaging and a low dose of the nanoparticle. Because of the efficient targeting scheme, 14% of the injected AuNP deposited at metastatic sites in the lungs within 60 min after injection, indicating that the vascular bed of metastasis is a viable target site for nanoparticles.

The amphiphilic nature of saponins and their effects on artificial and biological membranes and potential consequences for red blood and cancer cells

Saponins, amphiphiles of natural origin with numerous biological activities, are widely used in the cosmetic and pharmaceutical industry. Some saponins exhibit relatively selective cytotoxic effects on cancer cells but the tendency of saponins to induce hemolysis limits their anticancer potential. This review focused on the effects of saponin activity on membranes and consequent implications for red blood and cancer cells. This activity seems to be strongly related to the amphiphilic character of saponins that gives them the ability to self-aggregate and interact with membrane components such as cholesterol and phospholipids. Membrane interactions of saponins with artificial membrane models, red blood and cancer cells are reviewed with respect to their molecular structures. The review considered the mechanisms of these membrane interactions and their consequences including the modulation of membrane dynamics, interaction with membrane rafts, and membrane lysis. We summarized current knowledge concerning the mechanisms involved in the interactions of saponins with membrane lipids and examined the structure activity relationship of saponins regarding hemolysis and cancer cell death. A critical analysis of these findings speculates on their potential to further develop new anticancer compounds.

Redox-sensitive nanoparticles from amphiphilic cholesterol-based block copolymers for enhanced tumor intracellular release of doxorubicin

A novel amphiphilic cholesterol-based block copolymer comprised of a polymethacrylate bearing cholesterol block and a polyethylene glycol block with reducible disulfide bonds (PC5MA-SS-PEO) was synthesized and evaluated as a redox-sensitive nanoparticulate delivery system. The self-assembled PC5MA-SS-PEO nanoparticles (SS-NPs) encapsulated the anticancer drug doxorubicin (DOX) with high drug loading (18.2% w/w) and high encapsulation efficiency (94.9%). DOX-encapsulated PC5MA-SS-PEO self-assembled nanoparticles (DOX-encapsulated SS-NPs) showed excellent stability and exhibited a rapid DOX release in response to dithiothreitol reductive condition. Importantly, following internalization by lung cancer cells, the reducible DOX-encapsulated SS-NPs achieved higher cytotoxicity than the non-reducible thioester NPs whereas blank nanoparticles were non-cytotoxic. Furthermore, in vivo imaging studies in tumor-bearing severe combined immunodeficiency (SCID) mice showed that the nanoparticles preferentially accumulated in tumor tissue with remarkably reduced accumulation in the healthy non-target organs. The results indicated that the SS-NPs may be a promising platform for cancer-cell specific delivery of hydrophobic anticancer drugs.

FROM THE CLINICAL EDITOR

The use of nanocarriers for drug delivery against tumors has been under intense research. One problem of using carrier system is the drug release kinetics at tumor site. In this article, the authors continued their previous study in the development of an amphiphilic cholesterol-based block copolymer with redox-sensitive modification, so that the payload drug could be released in response to the microenvironment. The interesting results should provide a new direction for designing future novel nanocarrier systems.

DNA topology influences molecular machine lifetime in human serum

DNA nanotechnology holds the potential for enabling new tools for biomedical engineering, including diagnosis, prognosis, and therapeutics. However, applications for DNA devices are thought to be limited by rapid enzymatic degradation in serum and blood. Here, we demonstrate that a key aspect of DNA nanotechnology-programmable molecular shape-plays a substantial role in device lifetimes. These results establish the ability to operate synthetic DNA devices in the presence of endogenous enzymes and challenge the textbook view of near instantaneous degradation.

Systemic Targeting of Lymph Node Metastasis through the Blood Vascular System by Using Size-Controlled Nanocarriers

Occult nodal metastases increase the risk of cancer recurrence, demoting prognosis and quality of life of patients. While targeted drug delivery by using systemically administered nanocarriers can potentially control metastatic disease, lymph node metastases have been mainly dealt by locally injecting nanocarriers, which may not always be applicable. Herein, we demonstrated that sub-50 nm polymeric micelles incorporating platinum anticancer drugs could target lymph node metastases in a syngeneic melanoma model after systemic injection, even after removing the primary tumors, limiting the growth of the metastases. By comparing these micelles with clinically used doxorubicin-loaded liposomes (Doxil) having 80 nm, as well as a 70 nm version of the micelles, we found that the targeting efficiency of the nanocarriers against lymph node metastases was associated with their size-regulated abilities to extravasate from the blood vasculature in metastases and to penetrate within the metastatic mass. These findings indicate the potential of sub-50 nm polymeric micelles for developing effective conservative treatments against lymph node metastasis capable of reducing relapse and improving survival.

Redox-sensitive cross-linking enhances albumin nanoparticle function as delivery system for photodynamic cancer therapy

Photodynamic cancer therapy is still limited in its efficiency because of a lack of targeted methods avoiding non-specific toxicity. To overcome this we developed a system that is solely effective upon cellular uptake and intracellular activation by incorporating redox-sensitive chemistry. We used a nanoprecipitation method to obtain human serum albumin nanoparticles (HSA NP) with a diameter of 295 ± 5 nm and decorated them with the photosensitizer (PS) chlorin e6 (Ce6). The NP were stabilized using a redox-sensitive cross-linker to create a smart drug delivery system that is activated only upon NP disintegration in the reducing intracellular environment. Indeed, our drug delivery NP broke down in an environment emulating the reducing intracellular environment with 10 mM glutathione, but not under extracellular conditions. In contrast, the control cross-linked with glutaraldehyde did not break down in the reducing environment. Upon NP disintegration Ce6 fluorescence doubled as the result of diminished self-quenching. While the Ce6-HSA NP did not produce a significant amount of singlet oxygen upon irradiation, NP disintegration restored singlet oxygen production to about half of the value generated by the free Ce6. In vitro experiments with HeLa cells showed that the smart system was able to kill up to 81% of the cells while the glutaraldehyde cross-linked control only killed 56% of them at a drug concentration of 10 ng/ml. Also, Ce6 immobilization in HSA NP prevented dark toxicity in three different cell lines. For the first time, we demonstrate that it is possible to design a smart NP drug delivery system delivering a PS drug to cancer cells while avoiding toxicity prior to the uptake and irradiation. This finding may provide a means of designing more efficient PDT in cancer treatment.

Enhancing Accumulation and Penetration of HPMA Copolymer-Doxorubicin Conjugates in 2D and 3D Prostate Cancer Cells via iRGD Conjugation with an MMP-2 Cleavable Spacer

To enhance the accumulation and penetration of nanomedicines in tumor tissue, we developed and evaluated the biological properties of matrix metalloproteinase 2 (MMP-2)-responsive N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer drugs and tumor-penetrating peptide conjugates (P-DOX-PLGLAG-iRGD). Two different spacers were used in the design: a lysosomally (cathepsin B) cleavable tetrapeptide GFLG spacer conjugated doxorubicin (DOX) to HPMA copolymer, and an MMP-2-degradable linker (PLGLAG) connected tumor-homing and -penetrating cyclic peptide iRGD to HPMA copolymer. The accumulation of DOX in P-DOX-PLGLAG-iRGD-treated monolayer (2D) and multilayer (3D) DU-145 prostate cancer cells was higher than that of control groups (P-DOX and P-DOX + iRGD). The cell cycle arrest analysis and cytotoxicity data demonstrated that P-DOX-PLGLAG-iRGD produced a higher G2/M arrest and possessed stronger cytotoxicity against DU-145 cells than P-DOX + iRGD or P-DOX, which was consistent with the drug uptake results. Similarly, P-DOX-PLGLAG-iRGD demonstrated the highest penetration ability in 3D multicellular DU-145 tumor cell spheroids. The results indicate that covalent conjugation of iRGD via MMP-2-sensitive bonds enhances accumulation and penetration of nanomedicines into tumor cell monolayers and spheroids.

Cream formulation impact on topical administration of engineered colloidal nanoparticles

In order to minimize the impact of systemic toxicity of drugs in the treatment of local acute and chronic inflammatory reactions, the achievement of reliable and efficient delivery of therapeutics in/through the skin is highly recommended. While the use of nanoparticles is now an established practice for drug intravenous targeted delivery, their transdermal penetration is still poorly understood and this important administration route remains almost unexplored. In the present study, we have synthesized magnetic (iron oxide) nanoparticles (MNP) coated with an amphiphilic polymer, developed a water-in-oil emulsion formulation for their topical administration and compared the skin penetration routes with the same nanoparticles deposited as a colloidal suspension. Transmission and scanning electron microscopies provided ultrastructural evidence that the amphiphilic nanoparticles (PMNP) cream formulation allowed the efficient penetration through all the skin layers with a controllable kinetics compared to suspension formulation. In addition to the preferential follicular pathway, also the intracellular and intercellular routes were involved. PMNP that crossed all skin layers were quantified by inductively coupled plasma mass spectrometry. The obtained data suggests that combining PMNP amphiphilic character with cream formulation improves the intradermal penetration of nanoparticles. While PMNP administration in living mice via aqueous suspension resulted in preferential nanoparticle capture by phagocytes and migration to draining lymph nodes, cream formulation favored uptake by all the analyzed dermis cell types, including hematopoietic and non-hematopoietic. Unlike aqueous suspension, cream formulation also favored the maintenance of nanoparticles in the dermal architecture avoiding their dispersion and migration to draining lymph nodes via afferent lymphatics.

Using viruses as nanomedicines

The field of nanomedicine involves the design and fabrication of novel nanocarriers for the intracellular delivery of therapeutic cargo or for use in molecular diagnostics. Although traditionally recognized for their ability to invade and infect host cells, viruses and bacteriophages have been engineered over the past decade as highly promising molecular platforms for the targeted delivery and treatment of many human diseases. Inherently biodegradable, the outer capsids of viruses are composed entirely of protein building blocks, which can be genetically or chemically engineered with molecular imaging reagents, targeting ligands and therapeutic molecules. While there are several examples of viruses as in vitro molecular cargo carriers, their potential for applications in nanomedicine has only recently emerged. Here we highlight recent developments towards the design and engineering of viruses for the treatment of cancer, bacterial infections and immune system-related diseases.

Trifolium-like Platinum Nanoparticle-Mediated Photothermal Therapy Inhibits Tumor Growth and Osteolysis in a Bone Metastasis Model

Bone metastasis is a frequent and fatal complication of cancer that lacks effective clinical treatment. Photothermal therapy represents a new strategy for the destruction of multiple cancers. In this study, trifolium-like platinum nanoparticles (TPNs) with small size and excellent photothermal conversion property are prepared via a facile and green method. TPNs show minimal cytotoxicity on normal cell lines and kill cancer cells upon exposure to a near-infrared light. These nanoparticles effectively inhibit tumor growth and prevent osteolysis in a bone metastasis model. This study offers a promising strategy in the treatment of bone metastasis.

Enhancing anti-tumor efficacy of Doxorubicin by non-covalent conjugation to gold nanoparticles - in vitro studies on feline fibrosarcoma cell lines

Background

Feline injection-site sarcomas are malignant skin tumors of mesenchymal origin, the treatment of which is a challenge for veterinary practitioners. Methods of treatment include radical surgery, radiotherapy and chemotherapy. The most commonly used cytostatic drugs are cyclophosphamide, doxorubicin and vincristine. However, the use of cytostatics as adjunctive treatment is limited due to their adverse side-effects, low biodistribution after intravenous administration and multidrug resistance. Colloid gold nanoparticles are promising drug delivery systems to overcome multidrug resistance, which is a main cause of ineffective chemotherapy treatment. The use of colloid gold nanoparticles as building blocks for drug delivery systems is preferred due to ease of surface functionalization with various molecules, chemical stability and their low toxicity.

Methods

Stability and structure of the glutathione-stabilized gold nanoparticles non-covalently modified with doxorubicin (Au-GSH-Dox) was confirmed using XPS, TEM, FT-IR, SAXRD and SAXS analyses. MTT assay, Annexin V and Propidium Iodide Apoptosis assay and Rhodamine 123 and Verapamil assay were performed on 4 feline fibrosarcoma cell lines (FFS1WAW, FFS1, FFS3, FFS5). Statistical analyses were performed using Graph Pad Prism 5.0 (USA).

Results

A novel approach, glutathione-stabilized gold nanoparticles (4.3 +/- 1.1 nm in diameter) non-covalently modified with doxorubicin (Au-GSH-Dox) was designed and synthesized. A higher cytotoxic effect (p<0.01) of Au-GSH-Dox than that of free doxorubicin has been observed in 3 (FFS1, FFS3, FFS1WAW) out of 4 feline fibrosarcoma cell lines. The effect has been correlated to the activity of glycoprotein P (main efflux pump responsible for multidrug resistance).

Conclusions

The results indicate that Au-GSH-Dox may be a potent new therapeutic agent to increase the efficacy of the drug by overcoming the resistance to doxorubicin in feline fibrosarcoma cell lines. Moreover, as doxorubicin is non-covalently attached to glutathione coated nanoparticles the synthesized system is potentially suitable to a wealth of different drug molecules.

Large-Scale Silica Overcoating of Gold Nanorods with Tunable Shell Thicknesses

Gold nanorods (GNRs) overcoated with SiO2 are of interest for enhancing the shape stability of GNRs during photo-thermal heating, for further functionalization with silanes, and for biomedical applications. While methods have recently been developed for synthesizing GNRs on a large scale, SiO2 overcoating of GNRs is still conducted on a small reaction scale. Here, we report a method for large-scale synthesis of SiO2-overcoated GNRs (SiO2-GNRs), which gives ~190 mg of SiO2-GNRs. SiO2 is deposited onto and encapsulates the cetyltrimethylammonium bromide (CTAB) coatings that stabilize GNRs by adding tetraethoxysilane (TEOS) via syringe pump. Control over the CTAB concentration is critically important for obtaining uniform overcoatings. Optical absorbance spectra of SiO2-GNRs closely resemble uncoated GNRs, which indicates overcoating of single rather than multiple GNRs and confirms that they remain well dispersed. By adjusting the reaction conditions, shells as thick as ~20 nm can be obtained. For thin shells (< 10 nm), addition of poly(ethylene glycol) silane (PEG-silane) at different times during the overcoating reaction allows facile control over the shell thickness, giving shells as thin as ~2 nm. The bulky PEG chain terminates further crosslinking and deposition of SiO2.

Designing multivalent probes for tunable superselective targeting

Specific targeting is common in biology and is a key challenge in nanomedicine. It was recently demonstrated that multivalent probes can selectively target surfaces with a defined density of surface binding sites. Here we show, using a combination of experiments and simulations on multivalent polymers, that such "superselective" binding can be tuned through the design of the multivalent probe, to target a desired density of binding sites. We develop an analytical model that provides simple yet quantitative predictions to tune the polymer's superselective binding properties by its molecular characteristics such as size, valency, and affinity. This work opens up a route toward the rational design of multivalent probes with defined superselective targeting properties for practical applications, and provides mechanistic insight into the regulation of multivalent interactions in biology. To illustrate this, we show how the superselective targeting of the extracellular matrix polysaccharide hyaluronan to its main cell surface receptor CD44 is controlled by the affinity of individual CD44-hyaluronan interactions.

Theranostic applications of carbon nanomaterials in cancer: Focus on imaging and cargo delivery

Carbon based nanomaterials have attracted significant attention over the past decades due to their unique physical properties, versatile functionalization chemistry, and biological compatibility. In this review, we will summarize the current state-of-the-art applications of carbon nanomaterials in cancer imaging and drug delivery/therapy. The carbon nanomaterials will be categorized into fullerenes, nanotubes, nanohorns, nanodiamonds, nanodots and graphene derivatives based on their morphologies. The chemical conjugation/functionalization strategies of each category will be introduced before focusing on their applications in cancer imaging (fluorescence/bioluminescence, magnetic resonance (MR), positron emission tomography (PET), single-photon emission computed tomography (SPECT), photoacoustic, Raman imaging, etc.) and cargo (chemo/gene/therapy) delivery. The advantages and limitations of each category and the potential clinical utilization of these carbon nanomaterials will be discussed. Multifunctional carbon nanoplatforms have the potential to serve as optimal candidates for image-guided delivery vectors for cancer.

Superparamagnetic iron oxide nanoparticles for in vivo molecular and cellular imaging

In the last decade, the biomedical applications of nanoparticles (NPs) (e.g. cell tracking, biosensing, magnetic resonance imaging (MRI), targeted drug delivery, and tissue engineering) have been increasingly developed. Among the various NP types, superparamagnetic iron oxide NPs (SPIONs) have attracted considerable attention for early detection of diseases due to their specific physicochemical properties and their molecular imaging capabilities. A comprehensive review is presented on the recent advances in the development of in vitro and in vivo SPION applications for molecular imaging, along with opportunities and challenges.

Mesoscale nanoparticles selectively target the renal proximal tubule epithelium

We synthesized "mesoscale" nanoparticles, approximately 400 nm in diameter, which unexpectedly localized selectively in renal proximal tubules and up to 7 times more efficiently in the kidney than other organs. Although nanoparticles typically localize in the liver and spleen, modulating their size and opsonization potential allowed for stable targeting of the kidneys through a new proposed uptake mechanism. Applying this kidney targeting strategy, we anticipate use in the treatment of renal disease and the study of renal physiology.

Biodegradable nanoparticles sequentially decorated with Polyethyleneimine and Hyaluronan for the targeted delivery of docetaxel to airway cancer cells

Background

Novel polymeric nanoparticles (NPs) specifically designed for delivering chemotherapeutics in the body and aimed at improving treatment activity and selectivity, cover a very relevant area in the field of nanomedicine.

Here, we describe how to build a polymer shell of Hyaluronan (HA) and Polyethyleneimine (PEI) on biodegradable NPs of poly(lactic-co-glycolic) acid (PLGA) through electrostatic interactions and to achieve NPs with unique features of sustained delivery of a docetaxel (DTX) drug cargo as well as improved intracellular uptake.

Results

A stable PEI or HA/PEI shell could be obtained by careful selection of layering conditions. NPs with exquisite stability in salt and protein-rich media, with size and surface charge matching biological requirements for intravenous injection and endowed with sustained DTX release could be obtained. Cytotoxicity, uptake and activity of both PLGA/PEI/HA and PLGA/PEI NPs were evaluated in CD44(+) (A549) and CD44(−) (Calu-3) lung cancer cells. In fact, PEI-coated NPs can be formed after degradation/dissociation of the surface HA because of the excess hyaluronidases overexpressed in tumour interstitium. There was no statistically significant cytotoxic effect of PLGA/PEI/HA and PLGA/PEI NPs in both cell lines, thus suggesting that introduction of PEI in NP shell was not hampered by its intrinsic toxicity. Intracellular trafficking of NPs fluorescently labeled with Rhodamine (RHO) (RHO-PLGA/PEI/HA and RHO-PLGA/PEI NPs) demonstrated an increased time-dependent uptake only for RHO-PLGA/PEI/HA NPs in A549 cells as compared to Calu-3 cells. As expected, RHO-PLGA/PEI NP uptake in A549 cells was comparable to that observed in Calu-3 cells. RHO-PLGA/PEI/HA NPs internalized into A549 cells showed a preferential perinuclear localization. Cytotoxicity data in A549 cells suggested that DTX delivered through PLGA/PEI/HA NPs exerted a more potent antiproliferative activity than free DTX. Furthermore, DTX-PLGA/PEI NPs, as hypothetical result of hyaluronidase-mediated degradation in tumor interstitium, were still able to improve the cytotoxic activity of free DTX.

Conclusions

Taken together, results lead us to hypothesize that biodegradable NPs coated with a PEI/HA shell represent a very promising system to treat CD44 overexpressing lung cancer. In principle, this novel nanocarrier can be extended to different single drugs and drug combinations taking advantage of the shell and core properties.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-015-0088-2) contains supplementary material, which is available to authorized users.

Histamine-functionalized copolymer micelles as a drug delivery system in 2D and 3D models of breast cancer

Histamine functionalized block copolymers based on poly(allyl glycidyl ether)-b-poly(ethylene oxide) (PAGE-b-PEO) were prepared with different ratios of histamine and octyl or benzyl groups using UV-initiated thiol-ene click chemistry. At neutral pH, the histamine units are uncharged and hydrophobic, while in acidic environments, such as in the endosome, lysosomes, or extracellular sites of tumours, the histamine groups are positively charged and hydrophilic. pH responsible polymer drug delivery systems is a promising route to site specific delivery of drugs and offers the potential to avoid side effects of systemic treatment. Our detailed in vitro experiments of the efficacy of drug delivery and the intracellular localization characteristics of this library of NPs in 2D and 3D cultures of breast cancer revealed that the 50% histamine-modified polymer loaded with DOX exhibited rapid accumulation in the nucleus of free DOX within 2 h. Confocal studies showed enhanced mitochondrial localization and lysosomal escape when compared to controls. From these combined studies, it was shown that by accurately tuning the structure of the initial block copolymers, the resulting self-assembled NPs can be designed to exploit histamine as an endosomal escape trigger and the octyl/benzyl units give rise to a hydrophobic core resulting in highly efficacious drug delivery systems (DDS) with control over intracellular localization. Optimization and rational control of the intracellular localization of both DDS and the parent drug can give nanomedicines a substantial increase in efficacy and should be explored in future studies.

Joining time-resolved thermometry and magnetic-induced heating in a single nanoparticle unveils intriguing thermal properties

Whereas efficient and sensitive nanoheaters and nanothermometers are demanding tools in modern bio- and nanomedicine, joining both features in a single nanoparticle still remains a real challenge, despite the recent progress achieved, most of it within the last year. Here we demonstrate a successful realization of this challenge. The heating is magnetically induced, the temperature readout is optical, and the ratiometric thermometric probes are dual-emissive Eu(3+)/Tb(3+) lanthanide complexes. The low thermometer heat capacitance (0.021·K(-1)) and heater/thermometer resistance (1 K·W(-1)), the high temperature sensitivity (5.8%·K(-1) at 296 K) and uncertainty (0.5 K), the physiological working temperature range (295-315 K), the readout reproducibility (>99.5%), and the fast time response (0.250 s) make the heater/thermometer nanoplatform proposed here unique. Cells were incubated with the nanoparticles, and fluorescence microscopy permits the mapping of the intracellular local temperature using the pixel-by-pixel ratio of the Eu(3+)/Tb(3+) intensities. Time-resolved thermometry under an ac magnetic field evidences the failure of using macroscopic thermal parameters to describe heat diffusion at the nanoscale.

Monoclonal antibody-functionalized multilayered particles: targeting cancer cells in the presence of protein coronas

Engineered particles adsorb biomolecules (e.g., proteins) when introduced in a biological medium to form a layer called a "corona". Coronas, in particular the protein corona, play an important role in determining the surface properties of particles and their targeting abilities. This study examines the influence of protein coronas on the targeting ability of layer-by-layer (LbL)-assembled polymer capsules and core-shell particles functionalized with monoclonal antibodies. Upon exposure of humanized A33 monoclonal antibody (huA33 mAb)-functionalized poly(methacrylic acid) (PMA) capsules or huA33 mAb-PMA particles to human serum, a total of 83 or 65 proteins were identified in the protein coronas, respectively. Human serum of varying concentrations altered the composition of the protein corona. The antibody-driven specific cell membrane binding was qualitatively and quantitatively assessed by flow cytometry and fluorescence microscopy in both the absence and presence of a protein corona. The findings show that although different protein coronas formed in human serum (at different concentrations), the targeting ability of both the huA33 mAb-functionalized PMA capsules and particles toward human colon cancer cells was retained, demonstrating no significant difference compared with capsules and particles in the absence of protein coronas: ∼70% and ∼90% A33-expressing cells were targeted by the huA33 mAb-PMA capsules and particles, respectively, in a mixed cell population. This result demonstrates that the formation of protein coronas did not significantly influence the targeting ability of antibody-functionalized LbL-polymer carriers, indicating that the surface functionality of engineered particles in the presence of protein coronas can be preserved.

Trial Watch: Immunogenic cell death inducers for anticancer chemotherapy

The term "immunogenic cell death" (ICD) is now employed to indicate a functionally peculiar form of apoptosis that is sufficient for immunocompetent hosts to mount an adaptive immune response against dead cell-associated antigens. Several drugs have been ascribed with the ability to provoke ICD when employed as standalone therapeutic interventions. These include various chemotherapeutics routinely employed in the clinic (e.g., doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin) as well as some anticancer agents that are still under preclinical or clinical development (e.g., some microtubular inhibitors of the epothilone family). In addition, a few drugs are able to convert otherwise non-immunogenic instances of cell death into bona fide ICD, and may therefore be employed as chemotherapeutic adjuvants within combinatorial regimens. This is the case of cardiac glycosides, like digoxin and digitoxin, and zoledronic acid. Here, we discuss recent developments on anticancer chemotherapy based on ICD inducers.

Implantable hydrogel embedded dark-gold nanoswitch as a theranostic probe to sense and overcome cancer multidrug resistance

Multidrug resistance (MDR) in cancer cells is a substantial limitation to the success of chemotherapy. Here, we describe facile means to overcome resistance by silencing the multidrug resistance protein 1 (MRP1), before chemotherapeutic drug delivery in vivo with a single local application. Our platform contains hydrogel embedded with dark-gold nanoparticles modified with 5-fluorouracil (5-FU)-intercalated nanobeacons that serve as an ON/OFF molecular nanoswitch triggered by the increased MRP1 expression within the tumor tissue microenvironment. This nanoswitch can sense and overcome MDR prior to local drug release. The nanobeacons comprise a 5-FU intercalated DNA hairpin, which is labeled with a near-infrared (NIR) dye and a dark-quencher. The nanobeacons are designed to open and release the intercalated drug only upon hybridization of the DNA hairpin to a complementary target, an event that restores fluorescence emission due to nanobeacons conformational reorganization. Despite the cross-resistance to 5-FU, more than 90% tumor reduction is achieved in vivo in a triple-negative breast cancer model following 80% MRP1 silencing compared with the continuous tumor growth following only drug or nanobeacon administration. Our approach can be applied to reverse cross-resistance to other chemotherapeutic drugs and restore treatment efficacy. As a universal nanotheranostic probe, this platform can pave the way to early cancer detection and treatment.