Effects of nanoparticle surface-coupled peptides, functional endgroups, and charge on intracellular distribution and functionality of human primary reticuloendothelial cells

PEGylated Gold Nanoparticles Target Age-Associated B Cells In Vivo

Engineered gold nanoparticles (GNPs) have become a useful tool in various therapeutic and diagnostic applications. Uncertainty remains regarding the possible impact of GNPs on the immune system. In this regard, we investigated the interactions of polymer-coated GNPs with B cells and their functions in mice. Surprisingly, we observed that polymer-coated GNPs mainly interact with the recently identified subpopulation of B lymphocytes named age-associated B cells (ABCs). Importantly, we also showed that GNPs did not affect cell viability or the percentages of other B cell populations in different organs. Furthermore, GNPs did not activate B cell innate-like immune responses in any of the tested conditions, nor did they impair adaptive B cell responses in immunized mice. Together, these data provide an important contribution to the otherwise limited knowledge about GNP interference with B cell immune function, and demonstrate that GNPs represent a safe tool to target ABCs in vivo for potential clinical applications.

Gold Nanorods Induce Endoplasmic Reticulum Stress and Autocrine Inflammatory Activation in Human Neutrophils

Gold nanorods (AuNRs) are promising agents for diverse biomedical applications such as drug and gene delivery, bioimaging, and cancer treatment. Upon in vivo application, AuNRs quickly interact with cells of the immune system. On the basis of their strong intrinsic phagocytic activity, polymorphonuclear neutrophils (PMNs) are specifically equipped for the uptake of particulate materials such as AuNRs. Therefore, understanding the interaction of AuNRs with PMNs is key for the development of safe and efficient therapeutic applications. In this study, we investigated the uptake, intracellular processing, and cell biological response induced by AuNRs in PMNs. We show that uptake of AuNRs mainly occurs via phagocytosis and macropinocytosis with rapid deposition of AuNRs in endosomes within 5 min. Within 60 min, AuNR uptake induced an unfolded protein response (UPR) along with induction of inositol-requiring enzyme 1 α (IREα) and features of endoplasmic reticulum (ER) stress. This early response was followed by a pro-inflammatory autocrine activation loop that involves LOX1 upregulation on the cell surface and increased secretion of IL8 and MMP9. Our study provides comprehensive mechanistic insight into the interaction of AuNRs with immune cells and suggests potential targets to limit the unwanted immunopathological activation of PMNs during application of AuNRs.

Gold Nanoparticles: Multifaceted Roles in the Management of Autoimmune Disorders

Gold nanoparticles (GNPs) have been recently applied for various diagnostic and therapeutic purposes. The unique properties of these nanoparticles (NPs), such as relative ease of synthesis in various sizes, shapes and charges, stability, high drug-loading capacity and relative availability for modification accompanied by non-cytotoxicity and biocompatibility, make them an ideal field of research in bio-nanotechnology. Moreover, their potential to alleviate various inflammatory factors, nitrite species, and reactive oxygen production and the capacity to deliver therapeutic agents has attracted attention for further studies in inflammatory and autoimmune disorders. Furthermore, the characteristics of GNPs and surface modification can modulate their toxicity, biodistribution, biocompatibility, and effects. This review discusses in vitro and in vivo effects of GNPs and their functionalized forms in managing various autoimmune disorders (Ads) such as rheumatoid arthritis, type 1 diabetes, and multiple sclerosis.

Immunomodulatory Nanomedicine for the Treatment of Atherosclerosis

Atherosclerosis is the main underlying cause of cardiovascular diseases (CVDs), which remain the number one contributor to mortality worldwide. Although current therapies can slow down disease progression, no treatment is available that can fully cure or reverse atherosclerosis. Nanomedicine, which is the application of nanotechnology in medicine, is an emerging field in the treatment of many pathologies, including CVDs. It enables the production of drugs that interact with cellular receptors, and allows for controlling cellular processes after entering these cells. Nanomedicine aims to repair, control and monitor biological and physiological systems via nanoparticles (NPs), which have been shown to be efficient drug carriers. In this review we will, after a general introduction, highlight the advantages and limitations of the use of such nano-based medicine, the potential applications and targeting strategies via NPs. For example, we will provide a detailed discussion on NPs that can target relevant cellular receptors, such as integrins, or cellular processes related to atherogenesis, such as vascular smooth muscle cell proliferation. Furthermore, we will underline the (ongoing) clinical trials focusing on NPs in CVDs, which might bring new insights into this research field.

Lipid nanoparticle formulations for targeting leukocytes with therapeutic RNA in liver fibrosis

Obesity and low-grade inflammation are promoters of a multitude of diseases including liver fibrosis. Activation of the mobile leukocytes has a major impact on the outcome of inflammatory disease and can hence foster or mitigate liver fibrosis. This renders immunological targets valuable for directed interventions using nanomedicines. Particularly, RNA-based drugs formulated as lipid nanoparticles (LNP) can open new avenues for the personalized treatment of liver fibrosis both through specific interference and via the induction of the expression of functional and therapeutic proteins. Using microfluidics technology, all components, including lipid-anchored targeting ligands, are assembled in a single-step mixing process. A highlight is set to immunologically relevant liver cell types that are most vulnerable for being reached by LNP. A selection of LNP from other therapeutic fields applicable for reaching these cells in liver fbrosis is summarized. Furthermore, recent proceedings and major obstacles in the field of these targeted LNP are presented.

Anti-Tumor Metastasis via Platelet Inhibitor Combined with Photothermal Therapy under Activatable Fluorescence/Magnetic Resonance Bimodal Imaging Guidance

Photothermal therapy (PTT) is a promising tumor therapy strategy; however, heterogeneous heat distribution over the tumor often exists, resulting in insufficient photothermal ablation and potential risk of cancer metastasis, which has been demonstrated to be associate with platelets. Herein, a near-infrared (NIR) photothermal agent of IR780 was conjugated with MRI agent of Gd-DOTA via a disulfide linkage (ICD-Gd), which was coassembly with lipid connecting tumor-homing pentapeptide CREKA (Cys-Arg-Glu-Lys-Ala) (DSPE-PEG-CREKA) to encapsulate a platelet inhibitor of ticagrelor (Tic), affording a multistimuli-responsive nanosystem (DPC@ICD-Gd-Tic). The nanosystem with completely quenching fluorescence could specifically target the tumor-associated platelets and showed pH/reduction/NIR light-responsive drug release, which simultaneously resulting in dis-assembly of nanoparticle and fluorescence recovery, enabling the drug delivery visualization in tumor in situ via activatable NIR fluorescence/MR bimodal imaging. Finally, DPC@ICD-Gd-Tic further integrated the photoinduced hyperthermia and platelet function inhibitor to achieve synergistic anticancer therapy, leading to ablation of primary tumor cells and effectively suppressed their distant metastasis. The number of lung metastases in 4T1 tumor bearing mice was reduced by about 90%, and the size of tumor was reduced by about 70%, while half of the mouse was completely cured by this smart nanosystem.

A DM1-doped porous gold nanoshell system for NIR accelerated redox-responsive release and triple modal imaging guided photothermal synergistic chemotherapy

Background

Although many treatments for breast cancer are available, poor tumour targeting limits the effectiveness of most approaches. Consequently, it is difficult to achieve satisfactory results with monotherapies. The lack of accurate diagnostic and monitoring methods also limit the benefits of cancer treatment. The aim of this study was to design a nanocarrier comprising porous gold nanoshells (PGNSs) co-decorated with methoxy polyethylene glycol (mPEG) and trastuzumab (Herceptin®, HER), a therapeutic monoclonal antibody that binds specifically to human epidermal receptor-2 (HER2)-overexpressing breast cancer cells. Furthermore, a derivative of the microtubule-targeting drug maytansine (DM1) was incorporated in the PGNSs.

Methods

Prepared PGNSs were coated with mPEG, DM1 and HER via electrostatic interactions and Au–S bonds to yield DM1-mPEG/HER-PGNSs. SK-BR-3 (high HER2 expression) and MCF-7 (low HER2) breast cancer cells were treated with DM1-mPEG/HER-PGNSs, and cytotoxicity was evaluated in terms of cell viability and apoptosis. The selective uptake of the coated PGNSs by cancer cells and subsequent intracellular accumulation were studied in vitro and in vivo using inductively coupled plasma mass spectrometry and fluorescence imaging. The multimodal imaging feasibility and synergistic chemo-photothermal therapeutic efficacy of the DM1-mPEG/HER-PGNSs were investigated in breast cancer tumour-bearing mice. The molecular mechanisms associated with the anti-tumour therapeutic use of the nanoparticles were also elucidated.

Result

The prepared DM1-mPEG/HER-PGNSs had a size of 78.6 nm and displayed excellent colloidal stability, photothermal conversion ability and redox-sensitive drug release. These DM1-mPEG/HER-PGNSs were taken up selectively by cancer cells in vitro and accumulated at tumour sites in vivo. Moreover, the DM1-mPEG/HER-PGNSs enhanced the performance of multimodal computed tomography (CT), photoacoustic (PA) and photothermal (PT) imaging and enabled chemo-thermal combination therapy. The therapeutic mechanism involved the induction of tumour cell apoptosis via the activation of tubulin, caspase-3 and the heat shock protein 70 pathway. M2 macrophage suppression and anti-metastatic functions were also observed.

Conclusion

The prepared DM1-mPEG/HER-PGNSs enabled nanodart-like tumour targeting, visibility by CT, PA and PT imaging in vivo and powerful tumour inhibition mediated by chemo-thermal combination therapy in vivo. In summary, these unique gold nanocarriers appear to have good potential as theranostic nanoagents that can serve both as a probe for enhanced multimodal imaging and as a novel targeted anti-tumour drug delivery system to achieve precision nanomedicine for cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00824-5.

Innovative Nanotechnological Formulations to Reach the Hepatic Stellate Cell

Purpose of Review

Treatment of liver fibrosis benefits from hepatic stellate cell (HSC)-specific delivery. Since the description of first carrier to HSC, many developments have taken place in this area. The purpose is to give an overview of the different carriers and homing moieties that are available for HSC targeting and illustrate the opportunities and hurdles they provide.

Recent Findings

There is a growing number of homing devices to deliver drugs to HSC, and options to deliver siRNA to HSC have emerged. Other developments include controlling corona formation, development of linker technology, and design of theranostic approaches. We are on the eve of reaching the clinic with innovative HSC-specific compounds.

Summary

An overview of different core molecules is presented together with an overview of targeting strategies toward different receptors on HSC, providing a versatile toolbox. Many therapeutics, ranging from small chemical entities and proteins to RNA- or DNA-modulating substances, have already been incorporated in these constructs in the recent years.

Therapeutic Targeting of Neutrophil Granulocytes in Inflammatory Liver Disease

Neutrophil granulocytes are the most numerous type of leukocyte in humans bearing an enormous, yet largely unexplored therapeutic potential. Scientists have very recently increased their efforts to study and understand these cells which contribute to various types of inflammatory diseases and cancer. The mechanisms that regulate neutrophil recruitment to inflamed tissues and neutrophil cytotoxic activities against host tissues and pathogens require more attention. The reactive oxygen species (ROS) are a popular source of cellular stress and organ injury, and are critically expressed by neutrophils. By combating pathogens using molecular combat factors such as neutrophil extracellular traps (NETs), these are immobilized and killed i.e., by ROS. NETs and ROS are essential for the immune defense, but upon excessive activation, may also harm healthy tissue. Thus, exploring new routes for modulating their migration and activation is highly desired for creating novel anti-inflammatory treatment options. Leukocyte transmigration represents a key process for inflammatory cell infiltration to injury sites. In this review, we briefly summarize the differentiation and roles of neutrophils, with a spotlight on intravital imaging. We further discuss the potential of nanomedicines, i.e., selectin mimetics to target cell migration and influence liver disease outcome in animal models. Novel perspectives further arise from formulations of the wide array of options of small non-coding RNA such as small interfering RNA (siRNA) and micro-RNA (miR) which exhibit enzymatic functions: while siRNA binds and degrades a single mRNA based on full complementarity of binding, miR can up and down-regulate multiple targets in gene transcription and translation, mediated by partial complementarity of binding. Notably, miR is known to regulate at least 60% of the protein-coding genes and thus includes a potent strategy for a large number of targets in neutrophils. Nanomedicines can combine properties of different drugs in a single formulation, i.e., combining surface functionalization with ligands and drug delivery. Inevitably, nanomedicines accumulate in other phagocytes, a fact that should be controlled for every novel formulation to restrain activation of macrophages or modifications of the immunological synapse. Controlled drug release enabled by nanotechnological delivery systems may advance the options of modulating neutrophil activation and migration.

Small, Smaller, Nano: New Applications for Potato Virus X in Nanotechnology

Nanotechnology is an expanding interdisciplinary field concerning the development and application of nanostructured materials derived from inorganic compounds or organic polymers and peptides. Among these latter materials, proteinaceous plant virus nanoparticles have emerged as a key platform for the introduction of tailored functionalities by genetic engineering and conjugation chemistry. Tobacco mosaic virus and Cowpea mosaic virus have already been developed for bioimaging, vaccination and electronics applications, but the flexible and filamentous Potato virus X (PVX) has received comparatively little attention. The filamentous structure of PVX particles allows them to carry large payloads, which are advantageous for applications such as biomedical imaging in which multi-functional scaffolds with a high aspect ratio are required. In this context, PVX achieves superior tumor homing and retention properties compared to spherical nanoparticles. Because PVX is a protein-based nanoparticle, its unique functional properties are combined with enhanced biocompatibility, making it much more suitable for biomedical applications than synthetic nanomaterials. Moreover, PVX nanoparticles have very low toxicity in vivo, and superior pharmacokinetic profiles. This review focuses on the production of PVX nanoparticles engineered using chemical and/or biological techniques, and describes current and future opportunities and challenges for the application of PVX nanoparticles in medicine, diagnostics, materials science, and biocatalysis.

Applications of nanoparticles in biomedical imaging

An urgent need for early detection and diagnosis of diseases continuously pushes the advancements of imaging modalities and contrast agents. Current challenges remain for fast and detailed imaging of tissue microstructures and lesion characterization that could be achieved via development of nontoxic contrast agents with longer circulation time. Nanoparticle technology offers this possibility. Here, we review nanoparticle-based contrast agents employed in most common biomedical imaging modalities, including fluorescence imaging, MRI, CT, US, PET and SPECT, addressing their structure related features, advantages and limitations. Furthermore, their applications in each imaging modality are also reviewed using commonly studied examples. Future research will investigate multifunctional nanoplatforms to address safety, efficacy and theranostic capabilities. Nanoparticles as imaging contrast agents have promise to greatly benefit clinical practice.

Thermosensitive biomimetic polyisocyanopeptide hydrogels may facilitate wound repair

Changing wound dressings inflicts pain and may disrupt wound repair. Novel synthetic thermosensitive hydrogels based on polyisocyanopeptide (PIC) offer a solution. These gels are liquid below 16 °C and form gels beyond room temperature. The architecture and mechanical properties of PIC gels closely resemble collagen and fibrin, and include the characteristic stiffening response at high strains. Considering the reversible thermo-responsive behavior, we postulate that PIC gels are easy to apply and remove, and facilitate healing without eliciting foreign body responses or excessive inflammation. Biocompatibility may be higher in RGD-peptide-functionalized PIC gels due to enhanced cell binding capabilities. Full-thickness dorsal skin wounds in mice were compared to wounds treated with PIC gel and PIC-RGD gel for 3 and 7 days. No foreign body reactions and similar wound closure rates were found in all groups. The level of macrophages, myofibroblasts, epithelial migration, collagen expression, and blood vessels did not significantly differ from controls. Surprisingly, granulocyte populations in the wound decreased significantly in the PIC gel-treated groups, likely because foreign bacteria could not penetrate the gel. RGD-peptides did not further improve any effect observed for PIC. The absence of adverse effects, ease of application, and the possibilities for bio-functionalization make the biomimetic PIC hydrogels suitable for development into wound dressings.

Aluminium adjuvants used in vaccines

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To assess the benefits and harms of aluminium adjuvants used in a vaccine or an excipient versus the same vaccine or excipient, but having a different type of aluminium adjuvant formulation, or a different concentration, or with a different particle size.

Multifunctional core-shell nanoplatforms (gold@graphene oxide) with mediated NIR thermal therapy to promote miRNA delivery

Recent insights into the nanomedicine have revealed that nanoplatforms enhance the efficacy of carrier in therapeutic applications. Here, multifunctional nanoplatforms were utilized in miRNA-101 delivery and NIR thermal therapy to induce apoptosis in breast cancer cells. Au nanorods (NRs) or nanospheres (NSs) covered with graphene oxide (GO) were prepared and functionalized with polyethylene glycol as a stabilizer and poly-L-arginine (P-L-Arg) as a targeting agent. In nanoplatforms, coupling Au@GO prepared stable structures with higher NIR reactivity. P-L-Arg substantially enhanced the cellular uptake and gene retardation of stuffs coated by them. However, rod-shape nanoplatforms indicated better performance in cellular uptake and gene transfection than spherical ones. NIR thermal therapy was implemented to improve gene release and in synergy with miRNA-101 activated the apoptotic pathway and decreased the viability of breast cancer cell (<20%). Briefly, presented delivery systems are potentially efficient in distinguishing cancer cells, miRNA internalization and controlling apoptosis of cancer cells.

Immunomodulatory Therapy of Inflammatory Liver Disease Using Selectin-Binding Glycopolymers

Immunotherapies have the potential to significantly advance treatment of inflammatory disease and cancer, which are in large part driven by immune cells. Selectins control the first step in immune cell adhesion and extravasation, thereby guiding leukocyte trafficking to tissue lesions. We analyzed four different highly specific selectin-binding glycopolymers, based on linear poly(2-hydroxypropyl)-methacrylamide (PHPMA) polymers. These glycopolymers contain either the tetrasaccharide sialyl-Lewis^X (SLe^X) or the individual carbohydrates fucose, galactose, and sialic acids mimicking the complex SLe^X binding motive. The glycopolymers strongly bind to primary human macrophages, without activating them, and also to primary human blood leukocytes, but poorly to fibroblasts and endothelial cells in vitro. After intravenous injection in mice, all glycopolymers accumulated in the liver without causing hepatotoxicity. The glycosylated binder most potently targeted resident hepatic macrophages (Kupffer cells) and protected mice from acute toxic liver injury in the two different experimental models, carbon tetrachloride (CCl₄) or Concanavalin A (ConA)-based hepatitis. Its sulfated counterpart, on the other hand, induced a decrease in infiltrating and resident macrophages, increased T helper cells, and aggravated immune-mediated liver injury. We demonstrate that, in the context of selectin-binding glycopolymers, minor modifications strongly impact leukocyte influx and macrophage activation, thereby ameliorating or aggravating liver inflammation depending on the underlying immunopathology. The nonsulfated random glycopolymer is a promising candidate for the treatment of inflammatory disease. The modulation of hepatic immune cells by selectin-binding glycopolymers might breach the immunosuppressive hepatic microenvironment and could improve efficacy of immunotherapies for inflammatory disease and cancer.

Vincristine liposomes with smaller particle size have stronger diffusion ability in tumor and improve tumor accumulation of vincristine significantly

The passive targeting is the premise of active targeting that could make nanocarrier detained in tumor tissue. The particle size is the most important factor that influences the diffusion and distribution of nanoparticle both in vivo and in vitro. In order to investigate the relationship between particle size and diffusion ability, two kinds of liposome loaded with Vincristine (VCR-Lip) were prepared. The diffusion behavior of VCR-Lip with different particle size and free VCR was compared through diffusion stability study. The diffusion ability from 12-well culture plate to Millipore transwell of each formulation reflected on HepG-2 cytotoxicity results. Different cell placement methods and drug adding positions were used to study the VCR-Lip diffusion behaviors, which influenced the apoptosis of HepG-2 cell. The different cell uptake of Nile red–Lip and free Nile red was compared when changed the adding way of fluorescent fluorescein. To study the penetration ability in HepG-2 tumor spheroids, we constructed 30 nm and 100 nm Cy5.5-Lip to compare with free Cy5.5. Then the anti-tumor effect, tissue distribution of free VCR injection, 30 nm and 100 nm VCR-Lip were further investigated on the HepG-2 tumor bearing nude mice. The results of these study showed that the diffusion ability of free drug and fluorescent fluorescein was remarkable stronger than which encapsulated in liposomes. Moreover, diffusion ability of smaller liposome was stronger than larger one. In this way, 30 nm liposome had not only faster and stronger tumor distribution than 100 nm liposome, but also higher tumor drug accumulation than free drug as well. Our study provided a new thinking to improve the targeting efficiency of nano drug delivery system, no matter passive or active targeting.

Immunological properties of gold nanoparticles

In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be properly fabricated to deliver the cargo into the targeted cells through effective endocytosis. In this review, we discuss recent progress in understanding the selective penetration of gold nanoparticles into immune cells. The interaction of gold nanoparticles with immune cell receptors is discussed. As distinct from other published reviews, we present a summary of the immunological properties of gold nanoparticles. This review also summarizes what is known about the application of gold nanoparticles as an antigen carrier and adjuvant in immunization for the preparation of antibodies in vivo. For each of the above topics, the basic principles, recent advances, and current challenges are discussed. Thus, this review presents a detailed analysis of data on interaction of gold nanoparticles with immune cells. Emphasis is placed on the systematization of data over production of antibodies by using gold nanoparticles and adjuvant properties of gold nanoparticles. Specifically, we start our discussion with current data on interaction of various gold nanoparticles with immune cells. The next section describes existing technologies to improve production of antibodies in vivo by using gold nanoparticles conjugated with specific ligands. Finally, we describe what is known about adjuvant properties of bare gold or functionalized nanoparticles. In the Conclusion section, we present a short summary of reported data and some challenges and perspectives.

Immunotoxicity and genotoxicity testing of PLGA-PEO nanoparticles in human blood cell model

A human blood cell model for immunotoxicity and genotoxicity testing was used to measure the response to polylactic-co-glycolic acid (PLGA-PEO) nanoparticle (NP) (0.12, 3, 15 and 75 μg/cm(2) exposure in fresh peripheral whole blood cultures/isolated peripheral blood mononuclear cell cultures from human volunteers (n = 9-13). PLGA-PEO NPs were not toxic up to dose 3 μg/cm(2); dose of 75 μg/cm(2) displays significant decrease in [(3)H]-thymidine incorporation into DNA of proliferating cells after 4 h (70% of control) and 48 h (84%) exposure to NPs. In non-cytotoxic concentrations, in vitro assessment of the immunotoxic effects displayed moderate but significant suppression of proliferative activity of T-lymphocytes and T-dependent B-cell response in cultures stimulated with PWM > CON A, and no changes in PHA cultures. Decrease in proliferative function was the most significant in T-cells stimulated with CD3 antigen (up to 84%). Cytotoxicity of natural killer cells was suppressed moderately (92%) but significantly in middle-dosed cultures (4 h exposure). On the other hand, in low PLGA-PEO NPs dosed cultures, significant stimulation of phagocytic activity of granulocytes (119%) > monocytes (117%) and respiratory burst of phagocytes (122%) was recorded. Genotoxicity assessment revealed no increase in the number of micronucleated binucleated cells and no induction of SBs or oxidised DNA bases in PLGA-PEO-treated cells. To conclude on immuno- and genotoxicity of PLGA-PEO NPs, more experiments with various particle size, charge and composition need to be done.

Chitosan functionalisation of gold nanoparticles encourages particle uptake and induces cytotoxicity and pro-inflammatory conditions in phagocytic cells, as well as enhancing particle interactions with serum components

Background

Gold nanoparticles (AuNPs) are a popular choice for use in medical and biomedical research applications. With suitable functionalisation AuNPs can be applied in drug delivery systems, or can aid in disease diagnosis. One such functionalisation is with chitosan, which enables efficient interaction and permeation of cellular membranes, providing an effective adjuvant. As both AuNPs and chitosan have been shown to have low toxicity and high biocompatibility their proposed use in nanomedicine, either individually or combined, is expanding. However, further toxicological and immunological assessments of AuNP-chitosan conjugates are still needed. Therefore, we have evaluated how AuNP functionalisation with chitosan can affect uptake, cytotoxicity, and immunological responses within mononuclear cells, and influence the interaction of AuNPs with biomolecules within a complex biofluid. The AuNPs used were negatively charged through citrate-coating, or presented either low or high positive charge through chitosan-functionalisation. Uptake by THP-1 cells was assessed via transmission electron microscopy and electron energy loss spectroscopy, pro-inflammatory responses by ELISA and qRT-PCR, and cell death and viability via lactate dehydrogenase release and mitochondrial activity, respectively. Interactions of AuNPs with protein components of a frequently used in vitro cell culture medium supplement, foetal calf serum, were investigated using mass spectrometry.

Results

Although cells internalised all AuNPs, uptake rates and specific routes of intracellular trafficking were dependent upon chitosan-functionalisation. Accordingly, an enhanced immune response was found to be chitosan-functionalisation-dependent, in the form of CCL2, IL-1β, TNF-α and IL-6 secretion, and expression of IL-1β and NLRP3 mRNA. A corresponding increase in cytotoxicity was found in response to chitosan-coated AuNPs. Furthermore, chitosan-functionalisation was shown to induce an increase in unique proteins associating with these highly charged AuNPs.

Conclusions

It can be concluded that functionalisation of AuNPs with the perceived non-toxic biocompatible molecule chitosan at a high density can elicit functionalisation-dependent intracellular trafficking mechanisms and provoke strong pro-inflammatory conditions, and that a high affinity of these NP-conjugates for biomolecules may be implicit in these cellular responses.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-015-0146-9) contains supplementary material, which is available to authorized users.

Targeting myeloid cells using nanoparticles to improve cancer immunotherapy

While nanoparticles have traditionally been used to deliver cytotoxic drugs directly to tumors to induce cancer cell death, emerging data suggest that nanoparticles are likely to generate a larger impact on oncology through the delivery of agents that can stimulate antitumor immunity. Tumor-targeted nanocarriers have generally been used to localize chemotherapeutics to tumors and thus decrease off-target toxicity while enhancing efficacy. Challengingly, tumor heterogeneity and evolution render tumor-intrinsic approaches likely to succumb to relapse. The immune system offers exquisite specificity, cytocidal potency, and long-term activity that leverage an adaptive memory response. For this reason, the ability to manipulate immune cell specificity and function would be desirable, and nanoparticles represent an exciting means by which to perform such manipulation. Dendritic cells and tumor-associated macrophages are cells of the myeloid lineage that function as natural phagocytes, so they naturally take up nanoparticles. Dendritic cells direct the specificity and potency of cellular immune responses that can be targeted for cancer vaccines. Herein, we discuss the specific criteria needed for efficient vaccine design, including but not limited to the route of administration, size, morphology, surface charge, targeting ligands, and nanoparticle composition. In contrast, tumor-associated macrophages are critical mediators of immunosuppression whose trans-migratory abilities can be exploited to localize therapeutics to the tumor core and which can be directly targeted for elimination or for repolarization to a tumor suppressive phenotype. It is likely that a combination of targeting dendritic cells to stimulate antitumor immunity and tumor-associated macrophages to reduce immune suppression will impart significant benefits and result in durable antitumor responses.

Interaction of gold nanoparticles with proteins and cells

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

Macrophage silica nanoparticle response is phenotypically dependent

Phagocytes are important players in host exposure to nanomaterials. Macrophages in particular are believed to be among the "first responders" and primary cell types that uptake and process nanoparticles, mediating host biological responses by subsequent interactions with inflammatory signaling pathways and immune cells. However, variations in local microenvironmental cues can significantly change the functional and phenotype of these cells, impacting nanoparticle uptake and overall physiological response. Herein we focus on describing the response of specific RAW 264.7 macrophage phenotypes (M1, INF-gamma/LPS induced and M2, IL-4 induced) to Stöber silica nanoparticle exposure in vitro and how this response might correlate with macrophage response to nanoparticles in vivo. It was observed that variations in macrophage phenotype produce significant differences in macrophage morphology, silica nanoparticle uptake and toxicity. High uptake was observed in M1, versus low uptake in M2 cells. M2 cells also displayed more susceptibility to concentration dependent proliferative effects, suggesting potential M1 involvement in in vivo uptake. Nanoparticles accumulated within liver and spleen tissues, with high association with macrophages within these tissues and an overall Th1 response in vivo. Both in vitro and in vivo studies are consistent in demonstrating that silica nanoparticles exhibit high macrophage sequestration, particularly those with Th1/M1 phenotype and in clearance organs. This sequestration and phenotypic response should be a primary consideration when designing new Stöber silica nanoparticle systems, as it might affect the overall efficacy.

Therapeutic targeting of liver inflammation and fibrosis by nanomedicine

Nanomedicine constitutes the emerging field of medical applications for nanotechnology such as nanomaterial-based drug delivery systems. This technology may hold exceptional potential for novel therapeutic approaches to liver diseases. The specific and unspecific targeting of macrophages, hepatic stellate cells (HSC), hepatocytes, and liver sinusoidal endothelial cells (LSEC) using nanomedicine has been developed and tested in preclinical settings. These four major cell types in the liver are crucially involved in the complex sequence of events that occurs during the initiation and maintenance of liver inflammation and fibrosis. Targeting different cell types can be based on their capacity to ingest surrounding material, endocytosis, and specificity for a single cell type can be achieved by targeting characteristic structures such as receptors, sugar moieties or peptide sequences. Macrophages and especially the liver-resident Kupffer cells are in the focus of nanomedicine due to their highly efficient and unspecific uptake of most nanomaterials as well as due to their critical pathogenic functions during inflammation and fibrogenesis. The mannose receptor enables targeting macrophages in liver disease, but macrophages can also become activated by certain nanomaterials, such as peptide-modified gold nanorods (AuNRs) that render them proinflammatory. HSC, the main collagen-producing cells during fibrosis, are currently targeted using nanoconstructs that recognize the mannose 6-phosphate and insulin-like growth factor II, peroxisome proliferator activated receptor 1, platelet-derived growth factor (PDGF) receptor β, or integrins. Targeting of the major liver parenchymal cell, the hepatocyte, has only recently been achieved with high specificity by mimicking apolipoproteins, naturally occurring nanoparticles of the body. LSEC were found to be targeted most efficiently using carboxy-modified micelles and their integrin receptors. This review will summarize important functions of these cell types in healthy and diseased livers and discuss current strategies of cell-specific targeting for liver diseases by nanomedicine.

Liposomal encapsulation of dexamethasone modulates cytotoxicity, inflammatory cytokine response, and migratory properties of primary human macrophages

The encapsulation of drugs into liposomes aims to enhance their efficacy and reduce their toxicity. Corticosteroid-loaded liposomes are currently being evaluated in patients suffering from rheumatoid arthritis, atherosclerosis, colitis, and cancer. Here, using several different fluorophore-labeled formulations, we comprehensively studied the impact of liposome encapsulation of the prototypic corticosteroid dexamethasone on various primary human cells in vitro. Liposomal dexamethasone targeted several primary cell types in a dose and time-dependent manner, but specifically reduced cytotoxicity against human fibroblasts and macrophages in comparison to the solute drug. Furthermore, macrophage maturation and polarization markers were altered. Interestingly, liposomal dexamethasone induced proinflammatory cytokine secretion (specifically TNF, IL1β, IL6) in unstimulated cells, but reduced this response under inflammatory conditions. Monocyte and macrophage migration was significantly inhibited by dexamethasone-loaded liposomes. The findings indicate that the encapsulation of dexamethasone into liposomes modulates their cellular mechanism of action, and provides important indications for follow-up in vivo investigations.

FROM THE CLINICAL EDITOR

This study investigates mechanism of action of liposomal dexamethason in the treatment of inflammatory conditions. It is concluded that liposomal dexamethasone actually induces proinflammatory cytokine secretion in unstimulated cells, but reduces the same response under inflammatory conditions. Monocyte and macrophage migration was also inhibited. The findings indicate that liposomal dexamethasone may have different mechanisms of action than its native counterpart.

Biodistribution and clearance of a filamentous plant virus in healthy and tumor-bearing mice

Aim: Nanoparticles based on plant viruses are emerging biomaterials for medical applications such as drug delivery and imaging. Their regular structures can undergo genetic and chemical modifications to carry large payloads of cargos, as well as targeting ligands. Of several such platforms under development, only few have been characterized in vivo. We recently introduced the filamentous plant virus, potato virus X (PVX), as a new platform. PVX presents with a unique nanoarchitecture and is difficult to synthesize chemically. Methods: Here, we present a detailed analysis of PVX biodistribution and clearance in healthy mice and mouse tumor xenograft models using a combination of ex vivo whole-organ imaging, quantitative fluorescence assays and immunofluorescence microscopy. Results & conclusion: While up to 30% of the PVX signal was from the colon, mammary and brain tumor tissues, remaining particles were cleared by the reticuloendothelial system organs (the spleen and liver), followed by slower processing and clearance through the kidneys and bile.

Original submitted 7 November 2012; Revised submitted 19 January 2013; Published online 9 July 2013

Intelligent design of multifunctional lipid-coated nanoparticle platforms for cancer therapy

Nanotechnology is rapidly evolving and dramatically changing the paradigms of drug delivery. The small sizes, unique chemical properties, large surface areas, structural diversity and multifunctionality of nanoparticles prove to be greatly advantageous for combating notoriously therapeutically evasive diseases such as cancer. Multifunctional nanoparticles have been designed to enhance tumor uptake through either passive or active targeting, while also avoiding reticuloendothelial system uptake through the incorporation of PEG onto the surface. First-generation nanoparticle systems, such as liposomes, are good carriers for drugs and nucleic acid therapeutics, although they have some limitations. These lipid bilayers are now being utilized as excellent carriers for drug-loaded, solid core particles such as iron oxide, mesoporus silica and calcium phosphate. In this article, their design, as well as their multifunctional role in cancer therapy are discussed.