Influences of size and surface coating of gold nanoparticles on inflammatory activation of macrophages

Inflammatory response of nanoparticles: Mechanisms, consequences, and strategies for mitigation

Numerous nano-dimensioned materials have been generated as a result of several advancements in nanoscale science such as metallic nanoparticles (mNPs) which have aided in the advancement of related research. As a result, several significant nanoscale materials are being produced commercially. It is expected that in the future, products that are nanoscale, like mNPs, will be useful in daily life. Despite certain benefits, widespread use of metallic nanoparticles and nanotechnology has negative effects and puts human health at risk because of their continual accumulation in closed biological systems, along with their complex and diverse migratory and transformation pathways. Once within the human body, nanoparticles (NPs) disrupt the body's natural biological processes and trigger inflammatory responses. These NPs can also affect the immune system by activating separate pathways that either function independently or interact with one another. Cytotoxic effects, inflammatory response, genetic material damage, and mitochondrial dysfunction are among the consequences of mNPs. Oxidative stress and reactive oxygen species (ROS) generation caused by mNPs depend upon a multitude of factors that allow NPs to get inside cells and interact with biological macromolecules and cell organelles. This review focuses on how mNPs cause inflammation and oxidative stress, as well as disrupt cellular signaling pathways that support these effects. In addition, possibilities and problems to be reduced are addressed to improve future research on the creation of safer and more environmentally friendly metal-based nanoparticles for commercial acceptance and sustainable use in medicine and drug delivery.

Therapeutic synthetic and natural materials for immunoengineering

Immunoengineering is a rapidly evolving field that has been driving innovations in manipulating immune system for new treatment tools and methods. The need for materials for immunoengineering applications has gained significant attention in recent years due to the growing demand for effective therapies that can target and regulate the immune system. Biologics and biomaterials are emerging as promising tools for controlling immune responses, and a wide variety of materials, including proteins, polymers, nanoparticles, and hydrogels, are being developed for this purpose. In this review article, we explore the different types of materials used in immunoengineering applications, their properties and design principles, and highlight the latest therapeutic materials advancements. Recent works in adjuvants, vaccines, immune tolerance, immunotherapy, and tissue models for immunoengineering studies are discussed.

Immunotoxicity of metal and metal oxide nanoparticles: from toxic mechanisms to metabolism and outcomes

The influence of metal and metal oxide nanomaterials on various fields since their discovery has been remarkable. They have unique properties, and therefore, have been employed in specific applications, including biomedicine. However, their potential health risks cannot be ignored. Several studies have shown that exposure to metal and metal oxide nanoparticles can lead to immunotoxicity. Different types of metals and metal oxide nanoparticles may have a negative impact on the immune system through various mechanisms, such as inflammation, oxidative stress, autophagy, and apoptosis. As an essential factor in determining the function and fate of immune cells, immunometabolism may also be an essential target for these nanoparticles to exert immunotoxic effects in vivo. In addition, the biodegradation and metabolic outcomes of metal and metal oxide nanoparticles are also important considerations in assessing their immunotoxic effects. Herein, we focus on the cellular mechanism of the immunotoxic effects and toxic effects of different types of metal and metal oxide nanoparticles, as well as the metabolism and outcomes of these nanoparticles in vivo. Also, we discuss the relationship between the possible regulatory effect of nanoparticles on immunometabolism and their immunotoxic effects. Finally, we present perspectives on the future research and development direction of metal and metal oxide nanomaterials to promote scientific research on the health risks of nanomaterials and reduce their adverse effects on human health.

Impact of Nanoparticle Physicochemical Properties on Protein Corona and Macrophage Polarization

Macrophages, the major component of the mononuclear phagocyte system, uptake and clear systemically administered nanoparticles (NPs). Therefore, leveraging macrophages as a druggable target may be advantageous to enhance NP-mediated drug delivery. Despite many studies focused on NP-cell interactions, NP-mediated macrophage polarization mechanisms are still poorly understood. This work aimed to explore the effect of NP physicochemical parameters (size and charge) on macrophage polarization. Upon exposure to biological fluids, proteins rapidly adsorb to NPs and form protein coronas. To this end, we hypothesized that NP protein coronas govern NP-macrophage interactions, uptake, and subsequent macrophage polarization. To test this hypothesis, model polystyrene NPs with various charges and sizes, as well as NPs relevant to drug delivery, were utilized. Data suggest that cationic NPs potentiate both M1 and M2 macrophage markers, while anionic NPs promote M1-to-M2 polarization. Additionally, anionic polystyrene nanoparticles (APNs) of 50 nm exhibit the greatest influence on M2 polarization. Proteomics was pursued to further understand the effect of NPs physicochemical parameters on protein corona, which revealed unique protein patterns based on NP charge and size. Several proteins impacting M1 and M2 macrophage polarization were identified within cationic polystyrene nanoparticles (CPNs) corona, while APNs corona included fewer M1 but more M2-promoting proteins. Nevertheless, size impacts protein corona abundance but not identities. Altogether, protein corona identities varied based on NP surface charge and correlated to dramatic differences in macrophage polarization. In contrast, NP size differentially impacts macrophage polarization, which is dominated by NP uptake level rather than protein corona. In this work, specific corona proteins were identified as a function of NP physicochemical properties. These proteins are correlated to specific macrophage polarization programs and may provide design principles for developing macrophage-mediated NP drug delivery systems.

Nano-Immunomodulation: A New Strategy for Skeletal Muscle Diseases and Aging?

The skeletal muscle has a very remarkable ability to regenerate upon injury under physiological conditions; however, this regenerative capacity is strongly diminished in physio-pathological conditions, such as those present in diseased or aged muscles. Many muscular dystrophies (MDs) are characterized by aberrant inflammation due to the deregulation of both the lymphoid and myeloid cell populations and the production of pro-inflammatory cytokines. Pathological inflammation is also observed in old muscles due to a systemic change in the immune system, known as "inflammaging". Immunomodulation represents, therefore, a promising therapeutic opportunity for different skeletal muscle conditions. However, the use of immunomodulatory drugs in the clinics presents several caveats, including their low stability in vivo, the need for high doses to obtain therapeutically relevant effects, and the presence of strong side effects. Within this context, the emerging field of nanomedicine provides the powerful tools needed to control the immune response. Nano-scale materials are currently being explored as biocarriers to release immunomodulatory agents in the damaged tissues, allowing therapeutic doses with limited off-target effects. In addition, the intrinsic immunomodulatory properties of some nanomaterials offer further opportunities for intervention that still need to be systematically explored. Here we exhaustively review the state-of-the-art regarding the use of nano-sized materials to modulate the aberrant immune response that characterizes some physio-pathological muscle conditions, such as MDs or sarcopenia (the age-dependent loss of muscle mass). Based on our learnings from cancer and immune tolerance induction, we also discuss further opportunities, challenges, and limitations of the emerging field of nano-immunomodulation.

From hurdle to springboard: The macrophage as target in biomaterial-based bone regeneration strategies

The past decade has seen a growing appreciation for the role of the innate immune response in mediating repair and biomaterial directed tissue regeneration. The long-held view of the host immune/inflammatory response as an obstacle limiting stem cell regenerative activity, has given way to a fresh appreciation of the pivotal role the macrophage plays in orchestrating the resolution of inflammation and launching the process of remodelling and repair. In the context of bone, work over the past decade has established an essential coordinating role for macrophages in supporting bone repair and sustaining biomaterial driven osteogenesis. In this review evidence for the role of the macrophage in bone regeneration and repair is surveyed before discussing recent biomaterial and drug-delivery based approaches that target macrophage modulation with the goal of accelerating and enhancing bone tissue regeneration.

Immunotoxicity responses to polystyrene nanoplastics and their related mechanisms in the liver of zebrafish (Danio rerio) larvae

Nanoplastics in aquatic environments may induce adverse immunotoxicity effects in fish. However, there is insufficient evidence on the visible immunotoxicity endpoints in the larval stages of fish. The liver plays an important role in systemic and local innate immunity in the fish. In this study, the hepatic inflammatory effects of polystyrene (PS) nanoplastic particles (NPs: 100 and 50 nm) and micron PS particles on transgenic zebrafish (Danio rerio) larvae were estimated using fluorescent-labeled neutrophils, macrophages, and liver-type inflammatory binding protein (fabp10a). Particles with smaller size induced higher aggregations of neutrophils and apoptosis of macrophages in the abdomen of the larvae, corresponding to greater hepatic inflammation in the larvae. NPs increased the expression of fabp10a in the larval livers in a dose- and size-dependent manner. PS particles of 50 nm at a concentration of 0.1 mg·L^-1 increased the expression of fabp10a in the larval liver by 21.90% (P < 0.05). The plausible mechanisms of these effects depend on their distribution and the generation of reactive oxygen species in the larvae. Metabonomic analysis revealed that the metabolic pathways of catabolic processes, amino acids, and purines were highly promoted by NPs, compared to micron PS particles. NPs also activate steroid hormone biosynthesis in zebrafish larvae, which may lead to the occurrence of immune-related diseases. For the first time, the liver was identified as the target organ for the immunotoxicity effects of NPs in the larval stage of fish.

Size-dependent impact of polystyrene microplastics on the toxicity of cadmium through altering neutrophil expression and metabolic regulation in zebrafish larvae

Insufficient evidence exists regarding the visible physiological toxic endpoints of MPs exposures on zebrafish larvae due to their small sizes. Herein, the impacts of micro-polystyrene particles (μ-PS) and 100 nm polystyrene particles (n-PS) on the toxicity of cadmium (Cd) through altering neutrophil expressions were identified and quantified in the transgenic zebrafish (Danio rerio) larvae Tg(lyz:DsRed2), and the effects were size-dependent. When exposed together with μ-PS, the amount of neutrophils in Cd treated zebrafish larvae decreased by 25.56% through reducing Cd content in the larvae. By contrast, although n-PS exposure caused lower Cd content in the larvae, the expression of neutrophils under their combined exposure remained high. The mechanism of immune toxicity was analyzed based on the results of metabonomics. n-PS induced high oxidative stress in the larvae, which promoted taurine metabolism and unsaturated fatty biosynthesis in n-PS + Cd treatment. This observation was accordance with the significant inhibition of the activities of superoxide dismutase and catalase enzymes detected in their combined treatment. Moreover, n-PS promoted the metabolic pathways of catabolic processes, amino acid metabolism, purine metabolism, and steroid hormone biosynthesis in Cd treated zebrafish larvae. Nanoplasctis widely coexist with other pollutants in the environment at relatively low concentrations. We conclude that more bio-markers of immune impact should be explored to identify their toxicological mechanisms and mitigate the effects on the environment.

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.

Gold Nanoparticles Dissolve Extracellularly in the Presence of Human Macrophages

INTRODUCTION

Gold nanoparticles (AuNPs) have the potential to be used in various biomedical applications, partly due to the inertness and stability of gold. Upon intravenous injection, the NPs interact with the mononuclear phagocyte system, first with monocytes in the blood and then with macrophages in tissue. The NP-macrophage interaction will likely affect the stability of the AuNPs, but this is seldom analyzed. This study aimed to elucidate the role of macrophages in the biodissolution of AuNPs and underlying mechanisms.

METHODS

With an in vitro dissolution assay, we used inductively coupled plasma mass spectrometry to quantitatively compare the dissolution of 5 and 20 nm AuNPs coated with citrate or PEG in cell medium alone or in the presence of THP1-derived macrophages at 24 hours. In addition, we analyzed the cell dose, compared extra- and intracellular dissolution, and explored the possible role of reactive nitrogen species.

RESULTS

The results showed a higher cellular dose of the citrate-coated AuNPs, but dissolution was mainly evident for those sized 5 nm, irrespective of coating. The macrophages clearly assisted the dissolution, which was approximately fivefold higher in the presence of macrophages. The dissolution, however, appeared to take place mainly extracellularly. Acellular experiments demonstrated that peroxynitrite can initiate oxidation of gold, but a ligand is required to keep the gold ions in solution.

CONCLUSION

This study suggests extracellular dissolution of AuNPs in the presence of macrophages, likely with the contribution of the release of reactive nitrogen species, and provides new insight into the fate of AuNPs in the body.

The role of morphology, shell composition and protein corona formation in Au/Fe3O4 composite nanoparticle mediated macrophage responses

The great interest in using nanoparticles (NPs) for biomedical applications is transversal to various materials despite the poorly understood correlation between their physicochemical properties and effects on the immune system. NPs, such as gold and Fe₃O₄, are generally regarded as safe, but the immunotoxicological profile of Au/Fe₃O₄ composite NPs with different physicochemical properties is not well documented. This study investigated the biological impact of Au/Fe₃O₄ composite NPs with different morphologies (spherical core-shell and flower-like) and shell composition in vitro to analyze their potential cytotoxic effects and inflammatory responses on RAW 264.7 cells. Au/Fe₃O₄ composite NPs with a flower-like structure (FLNPs) induce a pronounced reduction in cell viability compared with Au/Fe₃O₄ composite NPs with a spherical core-shell structure (CSNPs). The increased production of reactive oxygen species, which damages cellular membranes, might contribute to the cytotoxicity effect of FLNPs. However, CSNPs presented more RAW 264.7 cell adhesion and uptake than FLNPs. Remarkably, a significant TNF-α release was observed with CSNP treated RAW 264.7 cells other than that of FLNPs. Protein corona analysis revealed the adsorption of a distinct amount and profile of proteins on the surface of CSNPs and FLNPs. Given the similar particle size and ζ-potential of CSNPs and FLNPs under the cell culture condition, results indicate that the impact of Au/Fe₃O₄ composite NPs on the macrophage activity highly depends on their morphology, shell composition and protein corona profile.

Immunomodulatory biomaterials and their application in therapies for chronic inflammation-related diseases

The degree of tissue injuries such as the level of scarring or organ dysfunction, and the immune response against them primarily determine the outcome and speed of healing process. The successful regeneration of functional tissues requires proper modulation of inflammation-producing immune cells and bioactive factors existing in the damaged microenvironment. In the tissue repair and regeneration processes, different types of biomaterials are implanted either alone or by combined with other bioactive factors, which will interact with the immune systems including immune cells, cytokines and chemokines etc. to achieve different results highly depending on this interplay. In this review article, the influences of different types of biomaterials such as nanoparticles, hydrogels and scaffolds on the immune cells and the modification of immune-responsive factors such as reactive oxygen species (ROS), cytokines, chemokines, enzymes, and metalloproteinases in tissue microenvironment are summarized. In addition, the recent advances of immune-responsive biomaterials in therapy of inflammation-associated diseases such as myocardial infarction, spinal cord injury, osteoarthritis, inflammatory bowel disease and diabetic ulcer are discussed.

Gold Nanomaterial Engineering for Macrophage-Mediated Inflammation and Tumor Treatment

Macrophages play an important role in the body's immune defense process. Phenotype imbalance between M1 and M2 macrophages induced by inflammation-related disorders and tumor can also be reversibly converted to treat these diseases. As exogenous substances, a large part of gold-based nanomaterials interact with macrophages once they enter the body, which provides gold nanomaterials a huge advantage to act as imaging contrasts, active substance carriers, and therapeutic agents for macrophage modulation. By cutting off macrophage recruitment, inhibiting macrophage activities, and modulating M1/M2 polarization, gold nanomaterial engineering exerts therapeutic effects on inflammation-related diseases at target sites. In this review, biological functions of macrophages in inflammation-related diseases are introduced, the effect of physicochemical factors of gold nanomaterials including size, shape, and surface chemistry is focused on the interaction between macrophages and gold nanomaterials, and the applications of gold nanomaterials are elaborated for tracking and treating these diseases by macrophages. The rational and smart engineering of gold nanomaterials allows a promising platform for macrophage-mediated inflammation and tumor imaging and treatment.

Size-Dependent Antibacterial Immunity of Staphylococcus aureus Protoplast-Derived Particulate Vaccines

Background

Vaccination provides a viable alternative to antibiotics for the treatment of drug-resistant bacterial infection. Bacterial protoplasts have gained much attention for a new generation vaccine due to depleting toxic outer wall components.

Purpose

The objective of this study was to reveal the effects of bacterial protoplast-derived nanovesicles (PDNVs) size on antibacterial immunity.

Methods

Herein, we prepared bacterial PDNVs with different sizes by removing the cell wall of Staphylococcus aureus (S. aureus) to generate multi-antigen nanovaccines. Furthermore, we investigated the ability of PDNVs in different sizes to activate dendritic cells (DCs) and trigger humoral and cellular immune responses in vivo.

Results

We obtained particles of ∼200 nm, 400 nm, and 700 nm diameters and found that all the PDNVs readily induce efficient maturation of DCs in the draining lymph nodes of the vaccinated mice. Dramatically, the activation of DCs was increased with decreasing particle sizes. In addition, vaccination with PDNVs generated elevated expression levels of specific antibody and the production of INF-γ, especially the smaller ones, indicating the capability of inducing strong humoral immunity and Th1 biased cell responses against the source bacteria.

Conclusion

These observed results provide evidence for size-dependent orchestration of immune responses of PDNVs and help to rationally design and develop effective antibacterial vaccines.

Effect of Gold Nanoparticles on the TLR2-Mediated Inflammatory Responses Induced by Leptospira in TLR2-Overexpressed HEK293 Cells

Leptospira infection can cause potential hazards to human health by stimulating inflammation, which is mediated mainly through the Toll-like receptor 2 (TLR2) pathway. Gold nanoparticles (AuNPs) are promising for medical applications, as they display both bioinert and noncytotoxic characteristics. AuNPs have been shown to have the ability to modify immune responses. To understand the in vitro immunomodulatory effect of AuNPs in a Leptospira infection model, the activation of TLR2 expression was examined in HEK-Blue-hTLR2 cells treated with Leptospira serovars and/or AuNPs (10 and 20 nm). The ability of AuNPs to modulate an inflammatory response induced by Leptospira was examined in terms of transcript expression level modulation of three proinflammatory cytokines (tumor necrosis factor-α, interleukin (IL)-1β and IL-6) using two-stage quantitative real-time reverse transcriptase PCR. The results revealed that the administration of 10 nm AuNPs could augment the Leptospira-induced TLR2 signaling response and upregulate the expression of all three cytokine gene transcripts, whereas the 20 nm AuNPs attenuated the TLR2 activation and expression of proinflammatory cytokines. This indicates that AuNPs can modulate inflammatory parameters in Leptospira infection and different-sized AuNPs had different immunomodulatory functions in this model.

Understanding Nanoparticle Toxicity to Direct a Safe-by-Design Approach in Cancer Nanomedicine

Nanomedicine is a rapidly growing field that uses nanomaterials for the diagnosis, treatment and prevention of various diseases, including cancer. Various biocompatible nanoplatforms with diversified capabilities for tumor targeting, imaging, and therapy have materialized to yield individualized therapy. However, due to their unique properties brought about by their small size, safety concerns have emerged as their physicochemical properties can lead to altered pharmacokinetics, with the potential to cross biological barriers. In addition, the intrinsic toxicity of some of the inorganic materials (i.e., heavy metals) and their ability to accumulate and persist in the human body has been a challenge to their translation. Successful clinical translation of these nanoparticles is heavily dependent on their stability, circulation time, access and bioavailability to disease sites, and their safety profile. This review covers preclinical and clinical inorganic-nanoparticle based nanomaterial utilized for cancer imaging and therapeutics. A special emphasis is put on the rational design to develop non-toxic/safe inorganic nanoparticle constructs to increase their viability as translatable nanomedicine for cancer therapies.

Redispersion of cryoaggregated gold nanoparticle by means of laser irradiation and effect on biological interactions

Agglomeration/aggregation is an indispensable phenomenon observed by different nanoparticles. In the present study, commercial grade (50 nm) and chemically synthesized (40 nm) gold nanoparticles (AuNPs) were aggregated at sub-zero temperatures, followed by disruption of the AuNP aggregates via nanosecond laser-ablation and subsequent effect on biological interactions. AuNPs were characterized pre/post laser-ablation via UV-visible spectroscopy, transmission electron microscopy, atomic force microscopy, etc. The process of freezing (aggregation) and laser-ablation (dispersion) was performed multiple times, in order to compare the yield of nanoparticles after each cycle of laser-ablation. Further, AuNPs pre/post laser-ablation were assessed for cytotoxicity, protein-corona formation, and cell-uptake by in vitro studies using RAW264.7, Caco-2 and Neuro-2 a cell lines. Aggregates for both the types of AuNPs displayed fragmentation following first cycle of laser-ablation. In addition, AuNPs obtained after fragmentation of the aggregates showed reduction in diameter and reshaping, as compared to native AuNPs. The size and shape of the nanoparticles after second and third cycle of laser-ablation was same as that obtained after first cycle of ablation. Both laser-ablated and native AuNPs showed similar effects on viability of RAW 264.7 and Caco-2 cells, after 24 h and 48 h of exposure. Cell uptake of native and laser-ablated AuNPs was observed to be a size dependent phenomenon. Present findings showed that nanosecond laser ablation of cryoaggregated AuNPs lead to changes in the physical properties of AuNPs post ablation like size and shape, however, biological interaction with cells remained same. This work is first report on biological interactions of AuNPs generated via laser-ablation of cryoaggregated AuNPs.

Magnetically Directed Enzyme/Prodrug Prostate Cancer Therapy Based on β-Glucosidase/Amygdalin

Background

β-Glucosidase (β-Glu) can activate amygdalin to kill prostate cancer cells, but the poor specificity of this killing effect may cause severe general toxicity in vivo, limiting the practical clinical application of this approach.

Materials and Methods

In this study, starch-coated magnetic nanoparticles (MNPs) were successively conjugated with β-Glu and polyethylene glycol (PEG) by chemical coupling methods. Cell experiments were used to confirm the effects of immobilized β-Glu on amygdalin-mediated prostate cancer cell death in vitro. Subcutaneous xenograft models were used to carry out the targeting experiment and magnetically directed enzyme/prodrug therapy (MDEPT) experiment in vivo.

Results

Immobilized β-Glu activated amygdalin-mediated prostate cancer cell death. Tumor-targeting studies showed that PEG modification increased the accumulation of β-Glu-loaded nanoparticles in targeted tumor tissue subjected to an external magnetic field and decreased the accumulation of the nanoparticles in the liver and spleen. Based on an enzyme activity of up to 134.89 ± 14.18mU/g tissue in the targeted tumor tissue, PEG-β-Glu-MNP/amygdalin combination therapy achieved targeted activation of amygdalin and tumor growth inhibition in C57BL/6 mice bearing RM1 xenografts. Safety evaluations showed that this strategy had some impact on liver and heart function but did not cause obvious organ damage.

Conclusion

All findings indicate that this magnetically directed enzyme/prodrug therapy strategy has the potential to become a promising new approach for targeted therapy of prostate cancer.

PEG modification enhances the in vivo stability of bioactive proteins immobilized on magnetic nanoparticles

OBJECTIVE

To increase the in vivo stability of bioactive proteins via optimized loading methods.

RESULTS

β-Glucosidase (β-Glu), as a model protein, was immobilized on magnetic nanoparticles(denoted as MNP-β-Glu) by chemical coupling methods and was further modified by poly(ethylene glycol) (PEG) molecules (denoted as MNP-β-Glu-PEG) to increase its stability. The physicochemical properties of the as-prepared nanohybrids, including the particle size, zeta potential, and enzyme activity, were well characterized. The proper MNP/β-Glu feed ratio was important for optimizing the particle size. Analysis of enzyme activity showed that the stability of immobilized β-Glu compared with free β-Glu was lower in deionized water and higher in blood serum at 37 °C. MNP-β-Glu-PEG retained 77.9% of the initial activity within 30 days at 4 °C, whereas the free enzyme retained only 58.2%. Pharmacokinetic studies of Sprague-Dawley (SD) rats showed that the MNP-β-Glu-PEG group retained a higher enzyme activity in vivo (41.46% after 50 min) than the MNP-β-Glu group (0.03% after 50 min) and the β-Glu group (0.37% after 50 min). Moreover, in contrast to the MNP-β-Glu group, the enzyme activity was not fully synchronous with the decrease in the Fe concentration in the MNP-β-Glu-PEG group.

CONCLUSIONS

All findings indicated that the method of immobilization on magnetic nanoparticles and PEG modification is promising for the application of bioactive proteins in vivo.

Effect of naked and PEG-coated gold nanoparticles on histopathology and cytokines expression in rat liver and kidneys

Aim: To compare the effects of 5- and 50-nm naked and PEG-coated gold nanoparticles (AuNP) on proinflammatory cytokines (IL-1β, IL-6, TNF-α) expression and histopathological changes in liver and kidneys of rats. Materials & methods: Rats were injected with different nanoparticles and sacrificed after 24 h. Results: Both 5- and 50-nm AuNPs, and 50-nm PEG-AuNPs caused granular clumping of cytoplasm, edema and hydropic dystrophy in hepatic cells. Naked AuNPs of both sizes caused mild shrinkage, whereas 50-nm PEG-AuNPs enlarged the Bowman's space and capsule. Larger nanoparticles produced more profound mRNA expression of cytokines in both the organs. Conclusion: These findings suggest the roles of particle size and coating on immunological response and histopathological changes.

Accelerated Bone Regeneration by Gold-Nanoparticle-Loaded Mesoporous Silica through Stimulating Immunomodulation

Bone repair and regeneration are greatly influenced by the local immune microenvironment. In this regard, the immunomodulatory capability of biomaterials should be considered when evaluating their osteogenic effects. In this study, we investigated the modulatory effects of gold nanoparticle (AuNP)-loaded mesoporous silica nanoparticles (Au-MSNs) on macrophages and the subsequent effects on the behavior of osteoblastic lineage cells. The results demonstrate that Au-MSNs could generate a favorable immune microenvironment by stimulating an anti-inflammatory response and promoting the secretion of osteogenic cytokines by macrophages. As a result, there is an enhancement of osteogenic differentiation in preosteoblastic MC3T3 cells as assessed by the increased expression of osteogenic markers, alkaline phosphatase (ALP) production, and calcium deposition. The immunomodulatory effects and direct osteogenic stimulation by Au-MSNs synergistically increased the osteogenic differentiation capability of MC3T3 cells as a result of crosstalk between Au-MSN-conditioned macrophages and Au-MSN-treated osteoblasts in a coculture system. An in vivo study further revealed that Au-MSNs could accelerate new bone formation in a critical-sized cranial defect site in rats based on computed tomography analysis and histological examination. Together, this novel Au-MSNs could significantly promote osteogenic activity by modulating the immune microenvironment, showing its therapeutic potential for bone tissue repair and regeneration.

Unintended effects of drug carriers: Big issues of small particles

Humoral and cellular host defense mechanisms including diverse phagocytes, leukocytes, and immune cells have evolved over millions of years to protect the body from microbes and other external and internal threats. These policing forces recognize engineered sub-micron drug delivery systems (DDS) as such a threat, and react accordingly. This leads to impediment of the therapeutic action, extensively studied and discussed in the literature. Here, we focus on side effects of DDS interactions with host defenses. We argue that for nanomedicine to reach its clinical potential, the field must redouble its efforts in understanding the interaction between drug delivery systems and the host defenses, so that we can engineer safer interventions with the greatest potential for clinical success.

Influences of surface coating of PLGA nanoparticles on immune activation of macrophages

Uptake of BSA-coated PLGA NPs induces a stronger inflammatory response which is represented by the up-expression of TNF-α.

Inflammatory activation of human serum albumin- or ovalbumin-modified chitosan particles to macrophages and their immune response in human whole blood

Chitosan particles modified with different albumins cause immune response in human whole blood via platelet activation and phagocytosis.