Targeting dendritic cells in lymph node with an antigen peptide-based nanovaccine for cancer immunotherapy

The design of peptide-based subunit vaccine formulations for the direct delivery of tumor antigen peptides (Aps) to dendritic cells (DCs) localized within draining lymph nodes (DLNs) is challenging. Mature DCs (mDCs) are abundantly distributed within DLNs but have dramatically reduced endocytic uptake and antigen-processing abilities, so their role as potential vaccine targets has been largely overlooked. Here we report an ultra-small biocompatible nanovaccine (α-Ap-FNP) functionalized by avidly targeting delivery of Ap via the scavenger receptor class B1 (SR-B1) pathway to mDCs. The self-assembly, small size (∼30 nm), SR-B1-targeting and optical properties of α-Ap-FNP resulted in its efficient Ap loading, substantial LN accumulation, targeting of mDCs and enhanced Ap presentation, and fluorescence trafficking, respectively. We also demonstrate that the α-Ap-FNP can be either used alone or encapsulated with CpG oligodeoxynucleotide as a prophylactic and therapeutic vaccine. Thus, the excellent properties of α-Ap-FNP provide it potential for clinical applications as a potent nanovaccine for cancer immunotherapy.

Nanomedicines Targeting the Tumor Microenvironment

We review recent progress in cancer nanomedicine to overcome the delivery barriers in tumor microenvironment, including the understanding in the nanomedicine delivery process, stimulus-responsive delivery, and several new strategies to normalize tumor microenvironment. The application of nanomedicine in cancer immunotherapy, a renewed cancer therapy by recent breakthrough, is also highlighted.

ZnO-Based Nanoplatforms for Labeling and Treatment of Mouse Tumors without Detectable Toxic Side Effects

ZnO quantum dots (QDs) were synthesized with polymer shells, coordinated with Gd(3+) ions and adsorbed doxorubicin (DOX) together to form a new kind of multifunctional ZnO-Gd-DOX nanoplatform. Such pH sensitive nanoplatforms were shown to release DOX to cancer cells in vitro and to mouse tumors in vivo, and reveal better specificity and lower toxicity than free DOX, and even better therapeutic efficacy than an FDA approved commercial DOX-loading drug DOX-Liposome Injection (DOXIL, NDA#050718). The ZnO-Gd-DOX nanoplatforms exhibited strong red fluorescence, which benefited the fluorescent imaging on live mice. Due to the special structure of ZnO-Gd-DOX nanoparticles, such nanoplatforms possessed a high longitudinal relaxivity r1 of 52.5 mM(-1) s(-1) at 0.55 T, which was superior to many other Gd(3+) based nanoparticles. Thus, both fluorescence labeling and magnetic resonance imaging could be applied simultaneously on the tumor bearing mice along with drug delivery. After 36 days of treatment on these mice, ZnO-Gd-DOX nanoparticles greatly inhibited the tumor growth without causing any appreciable abnormality in major organs. The most important merit of ZnO-Gd-DOX was that such a nanoplatform was biodegraded completely and showed no toxic side effects after H&E (hematoxylin and eosin) staining of tumor slices and ICP-AES (inductively coupled plasma atomic emission spectrometry) bioanalyses.

Programmed Nanococktail for Intracellular Cascade Reaction Regulating Self-Synergistic Tumor Targeting Therapy

In this work, a ZnO based nanococktail with programmed functions is designed and synthesized for self-synergistic tumor targeting therapy. The nanococktail can actively target tumors via specific interaction of hyaluronic acid (HA) with CD44 receptors and respond to HAase-rich tumor microenvironment to induce intracellular cascade reaction for controlled therapy. The exposed cell-penetrating peptide (R8) potentiates the cellular uptake of therapeutic nanoparticles into targeted tumor cells. Then ZnO cocktail will readily degrade in acidic endo/lysosomes and induce the production of desired reactive oxygen species (ROS) in situ. The destructive ROS not only leads to serious cell damage but also triggers the on-demand drug release for precise chemotherapy, thus achieving enhanced antitumor efficiency synergistically. After tail vein injection of ZnO cocktail, a favorable tumor apoptosis rate (71.2 ± 8.2%) is detected, which is significantly superior to that of free drug, doxorubicin (12.9 ± 5.2%). Both in vitro and in vivo studies demonstrate that the tailor-made ZnO cocktail with favorable biocompatibility, promising tumor specificity, and self-synergistically therapeutic capacity opens new avenues for cancer therapy.

Zinc-Containing Magnetic Oxides Stabilized by a Polymer: One Phase or Two?

Here we developed a new family of Zn-containing magnetic oxides of different structures by thermal decomposition of Zn(acac)2 in the reaction solution of preformed magnetite nanoparticles (NPs) stabilized by polyphenylquinoxaline. Upon an increase of the Zn(acac)2 loading from 0.15 to 0.40 mmol (vs 1 mmol of Fe(acac)3), the Zn content increases, and the Zn-containing magnetic oxide NPs preserve a spinel structure of magnetite and an initial, predominantly multicore NP morphology. X-ray photoelectron spectroscopy (XPS) of these samples revealed that the surface of iron oxide NPs is enriched with Zn, although Zn species were also found deep under the iron oxide NP surface. For all the samples, XPS also demonstrates the atom ratio of Fe(3+)/Fe(2+) = 2:1, perfectly matching Fe3O4, but not ZnFe2O4, where Fe(2+) ions are replaced with Zn(2+). The combination of XPS with other physicochemical methods allowed us to propose that ZnO forms an ultrathin amorphous layer on the surface of iron oxide NPs and also diffuses inside the magnetite crystals. At higher Zn(acac)2 loading, cubic ZnO nanocrystals coexist with magnetite NPs, indicating a homogeneous nucleation of the former. The catalytic testing in syngas conversion to methanol demonstrated outstanding catalytic properties of Zn-containing magnetic oxides, whose activities are dependent on the Zn loading. Repeat experiments carried out with the best catalyst after magnetic separation showed remarkable catalyst stability even after five consecutive catalytic runs.

Size-dependent redox behavior of iron observed by in-situ single nanoparticle spectro-microscopy on well-defined model systems

Understanding the chemistry of nanoparticles is crucial in many applications. Their synthesis in a controlled manner and their characterization at the single particle level is essential to gain deeper insight into chemical mechanisms. In this work, single nanoparticle spectro-microscopy with top-down nanofabrication is demonstrated to study individual iron nanoparticles of nine different lateral dimensions from 80 nm down to 6 nm. The particles are probed simultaneously, under same conditions, during in-situ redox reaction using X-ray photoemission electron microscopy elucidating the size effect during the early stage of oxidation, yielding time-dependent evolution of iron oxides and the mechanism for the inter-conversion of oxides in nanoparticles. Fabrication of well-defined system followed by visualization and investigation of singled-out particles eliminates the ambiguities emerging from dispersed nanoparticles and reveals a significant increase in the initial rate of oxidation with decreasing size, but the reactivity per active site basis and the intrinsic chemical properties in the particles remain the same in the scale of interest. This advance of nanopatterning together with spatially-resolved single nanoparticle X-ray absorption spectroscopy will guide future discourse in understanding the impact of confinement of metal nanoparticles and pave way to solve fundamental questions in material science, chemical physics, magnetism, nanomedicine and nanocatalysis.

Configuration-dependent Presentation of Multivalent IL-15:IL-15Rα Enhances the Antigen-specific T Cell Response and Anti-tumor Immunity

Here we report a "configuration-dependent" mechanism of action for IL-15:IL-15Rα (heterodimeric IL-15 or hetIL-15) where the manner by which IL-15:IL-15Rα molecules are presented to target cells significantly affects its function as a vaccine adjuvant. Although the cellular mechanism of IL-15 trans-presentation via IL-15Rα and its importance for IL-15 function have been described, the full effect of the IL-15:IL-15Rα configuration on responding cells is not yet known. We found that trans-presenting IL-15:IL-15Rα in a multivalent fashion on the surface of antigen-encapsulating nanoparticles enhanced the ability of nanoparticle-treated dendritic cells (DCs) to stimulate antigen-specific CD8(+) T cell responses. Localization of multivalent IL-15:IL-15Rα and encapsulated antigen to the same DC led to maximal T cell responses. Strikingly, DCs incubated with IL-15:IL-15Rα-coated nanoparticles displayed higher levels of functional IL-15 on the cell surface, implicating a mechanism for nanoparticle-mediated transfer of IL-15 to the DC surface. Using artificial antigen-presenting cells to highlight the effect of IL-15 configuration on DCs, we showed that artificial antigen-presenting cells presenting IL-15:IL-15Rα increased the sensitivity and magnitude of the T cell response, whereas IL-2 enhanced the T cell response only when delivered in a paracrine fashion. Therefore, the mode of cytokine presentation (configuration) is important for optimal immune responses. We tested the effect of configuration dependence in an aggressive model of murine melanoma and demonstrated significantly delayed tumor progression induced by IL-15:IL-15Rα-coated nanoparticles in comparison with monovalent IL-15:IL-15Rα. The novel mechanism of IL-15 transfer to the surface of antigen-processing DCs may explain the enhanced potency of IL-15:IL-15Rα-coated nanoparticles for antigen delivery.

Synthesis of bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles

Bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles were synthesized by a modified nanoemulsion process using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The morphology and crystal structure of the nanoparticles were studied by TEM/HRTEM and XRD. The nanoparticles manifest soft ferromagnetic and/or near superparamagnetic behavior with a small coercivity of ~19 Oe at room temperature. The corresponding magnetic hysteresis curves were elucidated by the modified Langevin equation. The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the nanoparticles. The UV-vis and PL results reveal the well-behaved absorption bands including surface plasmon resonance and multiple visible fingerprint photoluminescent emissions of the nanoparticles dispersed in both hydrophilic and hydrophobic solvents. Moreover, the processes of solvent dispersion-collection of the nanoparticles were demonstrated for application readiness of such core-shell nanostructures.

Engineering iodine-doped carbon dots as dual-modal probes for fluorescence and X-ray CT imaging

X-ray computed tomography (CT) is the most commonly used imaging technique for noninvasive diagnosis of disease. In order to improve tissue specificity and prevent adverse effects, we report the design and synthesis of iodine-doped carbon dots (I-doped CDs) as efficient CT contrast agents and fluorescence probe by a facile bottom-up hydrothermal carbonization process. The as-prepared I-doped CDs are monodispersed spherical nanoparticles (a diameter of ~2.7 nm) with favorable dispersibility and colloidal stability in water. The aqueous solution of I-doped CDs showed wavelength-dependent excitation and stable photoluminescence similar to traditional carbon quantum dots. Importantly, I-doped CDs displayed superior X-ray attenuation properties in vitro and excellent biocompatibility. After intravenous injection, I-doped CDs were distributed throughout the body and excreted by renal clearance. These findings validated that I-doped CDs with high X-ray attenuation potency and favorable photoluminescence show great promise for biomedical research and disease diagnosis.

Development of individualized anti-metastasis strategies by engineering nanomedicines

Metastasis is deadly and also tough to treat as it is much more complicated than the primary tumour. Anti-metastasis approaches available so far are far from being optimal. A variety of nanomedicine formulae provide a plethora of opportunities for developing new strategies and means for tackling metastasis. It should be noted that individualized anti-metastatic nanomedicines are different from common anti-cancer nanomedicines as they specifically target different populations of malignant cells. This review briefly introduces the features of the metastatic cascade, and proposes a series of nanomedicine-based anti-metastasis strategies aiming to block each metastatic step. Moreover, we also concisely introduce the advantages of several promising nanoparticle platforms and their potential for constructing state-of-the-art individualized anti-metastatic nanomedicines.

Improving cell-based therapies by nanomodification

Cell-based therapies are emerging as a promising approach for various diseases. Their therapeutic efficacy depends on rational control and regulation of the functions and behaviors of cells during their treatments. Different from conventional regulatory strategy by chemical adjuvants or genetic engineering, which is restricted by limited synergistic regulatory efficiency or uncertain safety problems, a novel approach based on nanoscale artificial materials can be applied to modify living cells to endow them with novel functions and unique properties. Inspired by natural "nano shell" and "nano compass" structures, cell nanomodification can be developed through both external and internal pathways. In this review, some novel cell surface engineering and intracellular nanoconjugation strategies are summarized. Their potential applications are also discussed, including cell protection, cell labeling, targeted delivery and in situ regulation. It is believed that these novel cell-material complexes can have great potentials for biomedical applications.

A Novel pseudo-Four-Component Domino Reaction for the Synthesis of Naphtho[2,1-b]furan-2(1H)-ones Using a Nanocatalyst

In this article, an original one-pot method is utilized to synthesize a variety of derivatives of naphtho[2,1-b]furan-2(1H)-one via a pseudo-four-component domino reaction of aryl aldehydes, acetic anhydride, hippuric acids, and 2-naphthols catalyzed by HSW@SPIONs. This reaction illustrates an array of attractive features including, with particular interest in this report, a convenient and unique process of creating and utilizing a powerful recyclable nanocatalyst.

Transfer of silica-coated magnetic (Fe3O4) nanoparticles through food: a molecular and morphological study in zebrafish

The increasing use of magnetic iron oxide nanoparticles (NPs) in biomedical applications has prompted extensive investigation of their interactions with biological systems also through animal models. A variety of toxic effects have been detected in NP-exposed fish and fish embryos, including oxidative stress and associated changes, such as lipid oxidation, apoptosis, and gene expression alterations. The main exposure route for fish is through food and the food web. This study was devised to investigate the effects of silica-coated NP administration through food in zebrafish (ZF, Danio rerio). Silica-coated magnetic NPs were administered to ZF through feed (zooplankton) from day 1 to 15 posthatching (ph). Larvae were examined 6 and 15 days ph and adults 3 and 6 months ph. A multidisciplinary approach, including morphometric examination; light, transmission electron, and confocal microscopy; inductively coupled plasma emission spectrometry; and real-time polymerase chain reaction, was applied to detect NP accumulation, structural and ultrastructural damage, and activation of detoxification processes in larvae and adults. Our findings document that the silica-coated NPs: (1) do not induce toxicity in ZF, (2) are excreted through feces, and (3) do not activate detoxification processes or promote tissue/cell injury.

'Smart' nanoparticles as drug delivery systems for applications in tumor therapy

INTRODUCTION

In the therapy of clinical diseases such as cancer, it is important to deliver drugs directly to tumor sites in order to maximize local drug concentration and reduce side effects. This objective may be realized by using 'smart' nanoparticles (NPs) as drug delivery systems, because they enable dramatic conformational changes in response to specific physical/chemical stimuli from the diseased cells for targeted and controlled drug release.

AREAS COVERED

In this review, we first briefly summarize the characteristics of 'smart' NPs as drug delivery systems in medical therapy, and then discuss their targeting transport, transmembrane and endosomal escape behaviors. Lastly, we focus on the applications of 'smart' NPs as drug delivery systems for tumor therapy.

EXPERT OPINION

Biodegradable 'smart' NPs have the potential to achieve maximum efficacy and drug availability at the desired sites, and reduce the harmful side effects for healthy tissues in tumor therapy. It is necessary to select appropriate NPs and modify their characteristics according to treatment strategies of tumor therapy.

Nanomaterials for enhanced immunity as an innovative paradigm in nanomedicine

Since the advent of nanoparticle technology, novel and versatile properties of nanomaterials have been introduced, which has constantly expanded their applications in therapeutics. Introduction of nanomaterials for immunomodulation has opened up new avenues with tremendous potential. Interesting properties of nanoparticles, such as adjuvanticity, capability to enhance cross-presentation, polyvalent presentation, siRNA delivery for silencing of immunesuppressive gene, targeting and imaging of immune cells have been known to have immense utility in vaccination and immunotherapy. A thorough understanding of the merits associated with nanomaterials is crucial for designing of modular and versatile nanovaccines, for improved immune response. With the emerging prerequisites of vaccination, nanomaterial-based immune stimulation, seems to be capable of taking the field of immunization to a next higher level.

Superparamagnetic MRI probes for in vivo tracking of dendritic cell migration with a clinical 3 T scanner

Dendritic cell (DC) based vaccines have shown promising results in the immunotherapy of cancers and other diseases. How to track the in vivo fate of DC vaccines will provide important insights to the final therapeutic results. In this study, we chose magnetic resonance imaging (MRI) to track murine DCs migration to the draining lymph node under a clinical 3 T scanner. Different from labeling immature DCs usually reported in literature, this study instead labeled matured DC with superparamagnetic iron oxide (SPIO) nanoparticle based imaging probes. The labeling process did not show negative impacts on cell viability, morphology, and surface biomarker expression. To overcome the imaging challenges brought by the limitations of the scanner, the size of lymph node, and the number of labeled cell, we optimized MRI pulse sequences. As a result, the signal reduction, caused either by gelatin phantoms containing as low as 12 SPIO-laden cells in each voxel or by the homing SPIO-laden DCs within the draining nodes after footpad injection of only 1 × 10(5) cells, can be clearly depicted under a 3 T MR scanner. Overall, the MRI labeling probes offer a low-toxic and high-efficient MR imaging platform for the assessment of DC-based immunotherapies.

Antigen-Loaded Upconversion Nanoparticles for Dendritic Cell Stimulation, Tracking, and Vaccination in Dendritic Cell-Based Immunotherapy

A dendritic cell (DC) vaccine, which is based on efficient antigen delivery into DCs and migration of antigen-pulsed DCs to draining lymph nodes after vaccination, is an effective strategy in initiating CD8(+) T cell immunity for immunotherapy. Herein, antigen-loaded upconversion nanoparticles (UCNPs) are used to label and stimulate DCs, which could be precisely tracked after being injected into animals and induce an antigen-specific immune response. It is discovered that a model antigen, ovalbumin (OVA), could be adsorbed on the surface of dual-polymer-coated UCNPs via electrostatic interaction, forming nanoparticle-antigen complexes, which are efficiently engulfed by DCs and induce DC maturation and cytokine release. Highly sensitive in vivo upconversion luminescence (UCL) imaging of nanoparticle-labeled DCs is successfully carried out, observing the homing of DCs to draining lymph nodes after injection. In addition, strong antigen-specific immune responses including enhanced T cell proliferation, interferon gamma (IFN-γ) production, and cytotoxic T lymphocyte (CTL)-mediated responses are induced by a nanoparticle-pulsed DC vaccine, which is promising for DC-based immunotherapy potentially against cancer.

MD2 expression is reduced in large airways of smokers and COPD smokers

Toll-like receptor 4 (TLR4) signaling requires a number of accessory proteins to initiate a signal. MD-2 is one of the accessory proteins with a relevant role in lipopolysaccharide responses. Although cigarette smoke increases TLR4 expression, TLR4 signaling is altered in smokers and in smokers COPD patients. The main aims of this study were to explore whether MD2 is altered in large and small airways of COPD and of smokers without COPD. The expression of MD2 ex vivo was assessed by immunohistochemistry in surgical specimens from current smokers COPD (s-COPD; n = 14), smokers without COPD (S; n = 7), and from non-smoker non-COPD subjects (C; n = 11. The in vitro effects of cigarette smoke extracts on the MD2 expression in a human bronchial epithelial cell line (16-HBE) were also assessed by flow cytometry. MD2 is reduced in the epithelium and in the submucosa in large airways but not in the epithelium and in the submucosa in small airways of smokers and of s-COPD. The expression of MD2 in the submucosa of the large airways is significantly higher in comparison to the submucosa of the small airways in all the studied groups. In vitro, cigarette smoke is able to increase TLR4 but it reduces MD2 in a dose-dependent manner in bronchial epithelial cells. Cigarette smoke may alter innate immune responses reducing the expression of the MD2, a molecule with an important role in TLR4 signaling.

Antitumor Activities of Metal Oxide Nanoparticles

Nanoparticles have received much attention recently due to their use in cancer therapy. Studies have shown that different metal oxide nanoparticles induce cytotoxicity in cancer cells, but not in normal cells. In some cases, such anticancer activity has been demonstrated to hold for the nanoparticle alone or in combination with different therapies, such as photocatalytic therapy or some anticancer drugs. Zinc oxide nanoparticles have been shown to have this activity alone or when loaded with an anticancer drug, such as doxorubicin. Other nanoparticles that show cytotoxic effects on cancer cells include cobalt oxide, iron oxide and copper oxide. The antitumor mechanism could work through the generation of reactive oxygen species or apoptosis and necrosis, among other possibilities. Here, we review the most significant antitumor results obtained with different metal oxide nanoparticles.

Tracking of dendritic cell migration into lymph nodes using molecular imaging with sodium iodide symporter and enhanced firefly luciferase genes

We sought to evaluate the feasibility of molecular imaging using the human sodium iodide symporter (hNIS) gene as a reporter, in addition to the enhanced firefly luciferase (effluc) gene, for tracking dendritic cell (DCs) migration in living mice. A murine dendritic cell line (DC2.4) co-expressing hNIS and effluc genes (DC/NF) was established. For the DC-tracking study, mice received either parental DCs or DC/NF cells in the left or right footpad, respectively, and combined I-124 PET/CT and bioluminescence imaging (BLI) were performed. In vivo PET/CT imaging with I-124 revealed higher activity of the radiotracer in the draining popliteal lymph nodes (DPLN) of the DC/NF injection site at day 1 than DC injection site (p < 0.05). The uptake value further increased at day 4 (p < 0.005). BLI also demonstrated migration of DC/NF cells to the DPLNs at day 1 post-injection, and signals at the DPLNs were much higher at day 4. These data support the feasibility of hNIS reporter gene imaging in the tracking of DC migration to lymphoid organs in living mice. DCs expressing the NIS reporter gene could be a useful tool to optimize various strategies of cell-based immunotherapy.

Design of magnetic nanoparticles for hepatocellular carcinoma treatment using the control mechanisms of the cell internal nucleus and external membrane

Nanoparticle drugs and relevant treatment technologies have achieved widespread attention in recent years. Hepatocellular carcinoma (HCC) remains a challenging malignancy of worldwide importance since it is one of the worst malignant tumors. In this study, magnetic Fe₃O₄ nanoparticles are prepared via a co-precipitation reaction with self-assembled surface monolayers of oleic acid molecules. For synthesizing the nanoparticle anti-tumor drug used against HCC, the liquid photo-immobilization method is used to bond the photoactive N-isopropylacrylamide derivative (NIPAm-AA) onto the oleic acid monolayer for subsequently embedding doxorubicin, photoactive tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ), and folic acid (FOL). We investigate how the nanoparticle drug inhibits the growth of human hepatocellular carcinoma HepG2 cells in vitro and in vivo. Remarkably, our characterizations show that the nanoparticle drug demonstrates much higher anticancer efficacy (94.7%) in vitro than previously reported drugs. It is revealed that the programmed cell death induced by the drug is mainly oncosis, a new programmed cell death pathway, different from earlier proposed mechanisms. This oncosis mechanism is also confirmed in the other two hepatocellular carcinoma cells (BEL-7402 and Huh-7). This study may be helpful for developing a new type of nanoparticle drug capable of assuring molecular control of both the cell inner nucleus and outer membrane as a means to enormously increase the drug efficacy in human hepatocellular carcinoma.

Fe₃O₄@ZnO core-shell nanocomposites for efficient and repetitive removal of low density lipoprotein in plasma and on blood vessel

Low density lipoprotein (LDL)-apheresis therapy, which directly removes LDL from plasma by LDL-adsorbents in vitro is found to be clinically effective and safe to lower the LDL content in blood to prevent cardiovascular disease. Thus, developing excellent LDL adsorbents are becoming more and more attractive. Herein, functional Fe3O4@ZnO core-shell nanocomposites have been synthesized by a facile and eco-friendly two-step method. Not only do they possess high LDL adsorption (in PBS/plasma as well as on blood vessels) and favorable magnetic targeting ability but they can also be reused conveniently, which offer the Fe3O4@ZnO core-shell nanocomposites significant potential in the removal of LDL in vitro and in vivo.

Inducing cells to disperse nickel nanowires via integrin-mediated responses

We present non-cytotoxic, magnetic, Arg-Gly-Asp (RGD)-functionalized nickel nanowires (RGD-nanowires) that trigger specific cellular responses via integrin transmembrane receptors, resulting in dispersal of the nanowires. Time-lapse fluorescence and phase contrast microscopy showed that dispersal of 3 μm long nanowire increased by a factor of 1.54 with functionalization by RGD, compared to polyethylene glycol (PEG), through integrin-specific binding, internalization and proliferation in osteosarcoma cells. Further, a 35.5% increase in cell density was observed in the presence of RGD-nanowires, compared to an increase of only 15.6% with PEG-nanowires. These results promise to advance applications of magnetic nanoparticles in drug delivery, hyperthermia, and cell separation where uniformity and high efficiency in cell targeting is desirable.

Functional manipulation of dendritic cells by photoswitchable generation of intracellular reactive oxygen species

Reactive oxygen species (ROS) play an important role in cellular signaling as second messengers. However, studying the role of ROS in physiological redox signaling has been hampered by technical difficulties in controlling their generation within cells. Here, we utilize two inert components, a photosensitizer and light, to finely manipulate the generation of intracellular ROS and examine their specific role in activating dendritic cells (DCs). Photoswitchable generation of intracellular ROS rapidly induced cytosolic mobilization of Ca(2+), differential activation of mitogen-activated protein kinases, and nuclear translocation of NF-κB. Moreover, a transient intracellular ROS surge could activate immature DCs to mature and potently enhance migration in vitro and in vivo. Finally, we observed that intracellular ROS-stimulated DCs enhanced antigen specific T-cell responses in vitro and in vivo, which led to delayed tumor growth and prolonged survival of tumor-bearing mice when immunized with a specific tumor antigen. Therefore, a transient intracellular ROS surge alone, if properly manipulated, can cause immature DCs to differentiate into a motile state and mature forms that are sufficient to initiate adaptive T cell responses in vivo.

Solid-binding peptides: smart tools for nanobiotechnology

Over the past decade, solid-binding peptides (SBPs) have been used increasingly as molecular building blocks in nanobiotechnology. These peptides show selectivity and bind with high affinity to the surfaces of a diverse range of solid materials including metals, metal oxides, metal compounds, magnetic materials, semiconductors, carbon materials, polymers, and minerals. They can direct the assembly and functionalisation of materials, and have the ability to mediate the synthesis and construction of nanoparticles and complex nanostructures. As the availability of newly synthesised nanomaterials expands rapidly, so too do the potential applications for SBPs.

Modulation of the tumor microenvironment for cancer treatment: a biomaterials approach

Tumors are complex tissues that consist of stromal cells, such as fibroblasts, immune cells and mesenchymal stem cells, as well as non-cellular components, in addition to neoplastic cells. Increasingly, there is evidence to suggest that these non-neoplastic cell components support cancer initiation, progression and metastasis and that their ablation or reprogramming can inhibit tumor growth. Our understanding of the activities of different parts of the tumor stroma in advancing cancer has been improved by the use of scaffold and matrix-based 3D systems originally developed for regenerative medicine. Additionally, drug delivery systems made from synthetic and natural biomaterials deliver drugs to kill stromal cells or reprogram the microenvironment for tumor inhibition. In this article, we review the impact of 3D tumor models in increasing our understanding of tumorigenesis. We also discuss how different drug delivery systems aid in the reprogramming of tumor stroma for cancer treatment.

Nanoparticle-based immunotherapy for cancer

The design of nanovaccines capable of triggering effective antitumor immunity requires an understanding of how the immune system senses and responds to threats, including pathogens and tumors. Equally important is an understanding of the mechanisms employed by tumor cells to evade immunity and an appreciation of the deleterious effects that antitumor immune responses can have on tumor growth, such as by skewing tumor cell composition toward immunologically silent tumor cell variants. The immune system and tumors engage in a tug-of-war driven by competition where promoting antitumor immunity or tumor cell death alone may be therapeutically insufficient. Nanotechnology affords a unique opportunity to develop therapeutic compounds than can simultaneously tackle both aspects, favoring tumor eradication. Here, we review the current status of nanoparticle-based immunotherapeutic strategies for the treatment of cancer, ranging from antigen/adjuvant delivery vehicles (to professional antigen-presenting cell types of the immune system) to direct tumor antigen-specific T-lymphocyte-targeting compounds and their combinations thereof.

Magnetic field-guided cell delivery with nanoparticle-loaded human corneal endothelial cells

To improve the delivery and integration of cell therapy using magnetic cell guidance for replacement of corneal endothelium, here we assess magnetic nanoparticles' (MNPs') effects on human corneal endothelial cells (HCECs) in vitro. Biocompatible, 50 nm superparamagnetic nanoparticles endocytosed by cultured HCECs induced no short- or long-term change in viability or identity. Assessment of guidance of the magnetic HCECs in the presence of different magnet shapes and field strengths showed a 2.4-fold increase in delivered cell density compared to gravity alone. After cell delivery, HCECs formed a functional monolayer, with no difference in tight junction formation between MNP-loaded and control HCECs. These data suggest that nanoparticle-mediated magnetic cell delivery may increase the efficiency of cell delivery without compromising HCEC survival, identity or function. Future studies may assess the safety and efficacy of this therapeutic modality in vivo. From the clinical editor: The authors show in this article that magnetic force facilitates the delivery of human corneal endothelial cells loaded by superparamagnetic nanoparticles to cornea, without changing their morphology, identity or functional properties. This novel idea can potentially have vast impact in the treatment of corneal endothelial dystrophies by providing self-endothelial cells after ex-vivo expansion.

Facile functionalization and assembly of live cells with microcontact-printed polymeric biomaterials

The functionalization and assembly of live cells with microfabricated polymeric biomaterials have attracted considerable interest in recent years, but the conventional methods suffer from high cost, high complexity, long processing time or inadequate capability. The present study reports on the development of a novel method for functionalizing and assembling live cells by integrating microcontact printing of polymeric biomaterials with a temperature-sensitive sacrificial layer prepared by spin-coating. This method has been used not only to functionalize live cells with microscopic polyelectrolyte and thermoplastic structures of various sizes and shapes, but also to assemble the cells into macroscopic stripes and sheets. The method is applicable to multiple types of cells, including human leukemic cells, mouse embryonic stem cells and human mesenchymal stem cells in the forms of single cells and cell aggregates. In addition, the microcontact-printed structures can be prepared using biodegradable and biocompatible polyelectrolytes and thermoplastic. The unique combination of low cost, ease of use and high versatility renders this method potentially useful for diverse biomedical applications, including drug delivery, cell tracking and tissue engineering.

Cancer immunotherapy: nanodelivery approaches for immune cell targeting and tracking

Cancer is one of the most common diseases afflicting people globally. New therapeutic approaches are needed due to the complexity of cancer as a disease. Many current treatments are very toxic and have modest efficacy at best. Increased understanding of tumor biology and immunology has allowed the development of specific immunotherapies with minimal toxicity. It is important to highlight the performance of monoclonal antibodies, immune adjuvants, vaccines and cell-based treatments. Although these approaches have shown varying degrees of clinical efficacy, they illustrate the potential to develop new strategies. Targeted immunotherapy is being explored to overcome the heterogeneity of malignant cells and the immune suppression induced by both the tumor and its microenvironment. Nanodelivery strategies seek to minimize systemic exposure to target therapy to malignant tissue and cells. Intracellular penetration has been examined through the use of functionalized particulates. These nano-particulate associated medicines are being developed for use in imaging, diagnostics and cancer targeting. Although nano-particulates are inherently complex medicines, the ability to confer, at least in principle, different types of functionality allows for the plausible consideration these nanodelivery strategies can be exploited for use as combination medicines. The development of targeted nanodelivery systems in which therapeutic and imaging agents are merged into a single platform is an attractive strategy. Currently, several nanoplatform-based formulations, such as polymeric nanoparticles, micelles, liposomes and dendrimers are in preclinical and clinical stages of development. Herein, nanodelivery strategies presently investigated for cancer immunotherapy, cancer targeting mechanisms and nanocarrier functionalization methods will be described. We also intend to discuss the emerging nano-based approaches suitable to be used as imaging techniques and as cancer treatment options.

Interface-controlled synthesis of heterodimeric silver-carbon nanoparticles derived from polysaccharides

Hybrid nanoparticles composed of multiple components can offer unique opportunities for understanding the nanoscale mechanism and advanced material applications. Here, we report the synthesis of heterodimeric silver-carbon dot nanoparticles (Ag-CD NPs) where the Ag NP is grown on the surface of CDs derived from polysaccharides, such as chitosan and alginate, through the photoelectron transfer reaction between CD and Ag(+) ions. The nanoscale interface between the Ag NPs and the CDs is highly tunable depending on the precursor of the CDs and the amount of additives, resulting in fine modification of photoluminescence of the CDs as well as the related surface plasmon resonance of the Ag NPs. This result demonstrates the critical role of the interface between the hybrid nanoparticles in governing the electrical and optical properties of respective nanoparticles.

Applications of nanomaterials as vaccine adjuvants

Vaccine adjuvants are applied to amplify the recipient's specific immune responses against pathogen infection or malignancy. A new generation of adjuvants is being developed to meet the demands for more potent antigen-specific responses, specific types of immune responses, and a high margin of safety. Nanotechnology provides a multifunctional stage for the integration of desired adjuvant activities performed by the building blocks of tailor-designed nanoparticles. Using nanomaterials for antigen delivery can provide high bioavailability, sustained and controlled release profiles, and targeting and imaging properties resulting from manipulation of the nanomaterials' physicochemical properties. Moreover, the inherent immune-regulating activity of particular nanomaterials can further promote and shape the cellular and humoral immune responses toward desired types. The combination of both the delivery function and immunomodulatory effect of nanomaterials as adjuvants is thought to largely benefit the immune outcomes of vaccination. In this review, we will address the current achievements of nanotechnology in the development of novel adjuvants. The potential mechanisms by which nanomaterials impact the immune responses to a vaccine and how physicochemical properties, including size, surface charge and surface modification, impact their resulting immunological outcomes will be discussed. This review aims to provide concentrated information to promote new insights for the development of novel vaccine adjuvants.

Complexity of danger: the diverse nature of damage-associated molecular patterns

In reply to internal or external danger stimuli, the body orchestrates an inflammatory response. The endogenous triggers of this process are the damage-associated molecular patterns (DAMPs). DAMPs represent a heterogeneous group of molecules that draw their origin either from inside the various compartments of the cell or from the extracellular space. Following interaction with pattern recognition receptors in cross-talk with various non-immune receptors, DAMPs determine the downstream signaling outcome of septic and aseptic inflammatory responses. In this review, the diverse nature, structural characteristics, and signaling pathways elicited by DAMPs will be critically evaluated.

Hybrid crystals comprising metal-organic frameworks and functional particles: synthesis and applications

Hybrid crystals containing encapsulated functional species exhibit promising novel physical and chemical properties. The realization of many properties critically depends on the selection of suitable functional species for incorporation, the rational control of the crystallinity of the host materials, and the manipulation of the distribution of the encapsulated species; only a few hybrid crystals achieve this. Here, a novel synthetic method enables the encapsulation of functional species within crystalline metal-organic frameworks (MOFs). Various kinds of single-crystalline MOFs with incorporated particles are presented. The encapsulated particles can be distributed in a controllable manner, and the hybrid crystals are applied to the heterogeneous catalysis of the reduction of nitroarenes. These findings suggest a general approach for the construction of MOF materials with potential applications; by combining species and MOFs with suitable functionalities, new properties--not possible by other means--may arise.

Post-ischemic inflammation regulates neural damage and protection

Post-ischemic inflammation is important in ischemic stroke pathology. However, details of the inflammation process, its resolution after stroke and its effect on pathology and neural damage have not been clarified. Brain swelling, which is often fatal in ischemic stroke patients, occurs at an early stage of stroke due to endothelial cell injury and severe inflammation by infiltrated mononuclear cells including macrophages, neutrophils, and lymphocytes. At early stage of inflammation, macrophages are activated by molecules released from necrotic cells [danger-associated molecular patterns (DAMPs)], and inflammatory cytokines and mediators that increase ischemic brain damage by disruption of the blood–brain barrier are released. After post-ischemic inflammation, macrophages function as scavengers of necrotic cell and brain tissue debris. Such macrophages are also involved in tissue repair and neural cell regeneration by producing tropic factors. The mechanisms of inflammation resolution and conversion of inflammation to neuroprotection are largely unknown. In this review, we summarize information accumulated recently about DAMP-induced inflammation and the neuroprotective effects of inflammatory cells, and discuss next generation strategies to treat ischemic stroke.

TLR4 inhibition impairs bacterial clearance in a therapeutic setting in murine abdominal sepsis

OBJECTIVE AND DESIGN

To investigate the therapeutic effect of E5564 (a clinically used TLR4 inhibitor) in murine abdominal sepsis elicited by intraperitoneal infection with a highly virulent Escherichia coli in the context of concurrent antibiotic therapy.

METHODS

Mice were infected with different doses (~2 × 10(4)-2 × 10(6) CFU) of E. coli O18:K1 and treated after 8 h with ceftriaxone 20 mg/kg i.p. combined with either E5564 10 mg/kg i.v. or vehicle. For survival studies this treatment was repeated every 12 h. Bacterial loads and inflammatory parameters were determined after 20 h in peritoneal lavage fluid, blood, liver and lung tissue. Plasma creatinin, AST, ALT and LDH were determined to assess organ injury.

RESULTS

E5564 impaired bacterial clearance under the antibiotic regime after infection with a low dose E. coli (1.7 × 10(4) CFU) while renal function was slightly preserved. No differences were observed in bacterial load and organ damage after infection with a tenfold higher (1.7 × 10(5) E. coli) bacterial dose. While treatment with E5564 slightly attenuated inflammatory markers provoked by the sublethal doses of 104-105 E. coli under the antibiotic regime, it did not affect lethality evoked by infection with 1.7 × 106 E. coli.

CONCLUSIONS

The impact of TLR4 inhibition during abdominal sepsis by virulent E. coli bacteria is only beneficial at low infection grade at cost of bactericidal activity.

Construction of a gastric cancer cell line with stably silenced expression of CD14

AIM: To develop a SGC-7901 cell line with stably silenced expression of CD14 to provide an experimental basis for the study of the pathogenesis of gastric cancer.

METHODS: A CD14-shRNA lentiviral vector was constructed to transfect gastric cancer SGC-7901 cells. RT-PCR and Western blot were used to detect the CD14 mRNA and protein levels in untreated SGC-7901 cells (blank control group), SGC-7901 cells transfected with NC-CD14 shRNA (NC-CD14 shRNA control group) and SGC-7901 cells transfected with the CD14-shRNA lentiviral vector (CD14-shRNA lentiviral vector group).

RESULTS: CD14-shRNA expression vector was successfully constructed and transfected into gastric cancer cells. RT-PCR showed that the Ct value for the CD14-shRNA lentiviral vector group was significantly higher than those for the NC-CD14 shRNA control group and blank control group (P = 0.000; P < 0.001), and the 2^Ct value for the CD14-shRNA lentiviral vector group (1±0.08) was significantly lower than those for the NC-CD14 shRNA control group and blank control group (P = 0.0001; P < 0.001). Western blot analysis showed that the relative expression of CD14 protein in the CD14-shRNA lentiviral vector group (0.01) was significantly less than that in the blank control group (1.0) and NC-CD14 shRNA control group (0.83).

CONCLUSION: A CD14-shRNA lentiviral vector has been successfully transfected into gastric cancer SGC-7901 cells, which can inhibit the expression of CD14 mRNA and protein in SGC-7901 cells.

Innate immune factors modulate ethanol interaction with GABAergic transmission in mouse central amygdala

Excessive ethanol drinking in rodent models may involve activation of the innate immune system, especially toll-like receptor 4 (TLR4) signaling pathways. We used intracellular recording of evoked GABAergic inhibitory postsynaptic potentials (eIPSPs) in central amygdala (CeA) neurons to examine the role of TLR4 activation by lipopolysaccharide (LPS) and deletion of its adapter protein CD14 in acute ethanol effects on the GABAergic system. Ethanol (44, 66 or 100mM) and LPS (25 and 50μg/ml) both augmented eIPSPs in CeA of wild type (WT) mice. Ethanol (44mM) decreased paired-pulse facilitation (PPF), suggesting a presynaptic mechanism of action. Acute LPS (25μg/ml) had no effect on PPF and significantly increased the mean miniature IPSC amplitude, indicating a postsynaptic mechanism of action. Acute LPS pre-treatment potentiated ethanol (44mM) effects on eIPSPs in WT mice and restored ethanol's augmenting effects on the eIPSP amplitude in CD14 knockout (CD14 KO) mice. Both the LPS and ethanol (44-66mM) augmentation of eIPSPs was diminished significantly in most CeA neurons of CD14 KO mice; however, ethanol at the highest concentration tested (100mM) still increased eIPSP amplitudes. By contrast, ethanol pre-treatment occluded LPS augmentation of eIPSPs in WT mice and had no significant effect in CD14 KO mice. Furthermore, (+)-naloxone, a TLR4-MD-2 complex inhibitor, blocked LPS effects on eIPSPs in WT mice and delayed the ethanol-induced potentiation of GABAergic transmission. In CeA neurons of CD14 KO mice, (+)-naloxone alone diminished eIPSPs, and subsequent co-application of 100mM ethanol restored the eIPSPs to baseline levels. In summary, our results indicate that TLR4 and CD14 signaling play an important role in the acute ethanol effects on GABAergic transmission in the CeA and support the idea that CD14 and TLR4 may be therapeutic targets for treatment of alcohol abuse.

Nanocarrier-based immunotherapy in cancer management and research

Research in cancer immunotherapy has gained momentum in the last two decades, with many studies and clinical trials showing positive therapeutic outcomes. Immunotherapy can elicit not only a strong anticancer immune response which could even control metastases, but could also induce immunological memory, resulting in long-lasting protection in the prophylactic setting and protection against possible recurrence. Nanocarriers offer an attractive means for delivery of a multitude of therapeutic immunomodulators which are readily taken up by immune cells and can initiate a particular arm of an immunostimulatory cascade leading to tumor cell killing. This review focuses on recent advances in nanocarrier-mediated immunotherapy for the treatment of cancer. Both in vitro and in vivo studies as well as clinical progress are discussed in various sections. Description of the specific role of nanoparticle technology in immunotherapy highlights the way particles can be tailor-made in terms of size, structure, payload, and surface properties for active targeting to antigen-presenting cells and/or enhanced accumulation in the solid tumor.