Controlling protein interactions in blood for effective liver immunosuppressive therapy by silica nanocapsules

Circulating immunotherapy strategy based on pyroptosis and STING pathway: Mn-loaded paclitaxel prodrug nanoplatform against tumor progression and metastasis

Immunotherapy has emerged as a promising strategy against tumors. However, its efficacy is limited by low immunogenicity, poor antigen presentation, and inadequate lymphocyte infiltration. Herein, we develop a nanoplatform (Mn-HSP) loaded with manganese ions (Mn2+) and paclitaxel (PTX) prodrug based on hyaluronic acid. PTX in Mn-HSP induces DNA damage and pyroptosis to release tumor-associated antigens (TAAs), enhancing tumor-specific adaptive immunity. Meanwhile, Mn2+ in Mn-HSP, together with PTX-induced DNA damage, activates the stimulator of interferon gene (STING) pathway to amplify innate immunity. Mn-HSP combines with adaptive and innate immunity, effectively enhancing the presentation of antigen-presenting cells (APCs) and promoting tumor infiltration of cytotoxic T lymphocytes (CTLs). In turn, the granzyme B (GZMB) secreted by CTLs triggers pyroptosis again, thereby establishing a "circulating immunotherapy" against tumors. Our results demonstrate that Mn-HSP efficiently inhibits primary breast tumors, as well as rechallenge tumors and lung metastasis in vivo. Therefore, the circulating immunotherapy that combines pyroptosis mediated adaptive immunity and STING pathway amplified innate immunity provides a novel strategy for enhancing tumor immunotherapy.

Anti-PEG antibodies enriched in the protein corona of PEGylated nanocarriers impact the cell uptake

Poly(ethylene glycol) (PEG) is the gold standard used to reduce unspecific protein adsorption and prolong nanocarrier circulation time. However, this stealth effect could be counteracted by the increasing prevalence of anti-PEG antibodies in the bloodstream. Up to now, the presence of anti-PEG antibodies in the protein corona and their effect on cell uptake has not been investigated yet. Our results showed a high concentration and prevalence of anti-PEG antibodies in the German population. PEGylated nanocarriers exhibited a higher level of anti-PEG antibodies in the protein corona compared to non-PEGylated, which lead to higher uptake in macrophages. Consequently, the anti-PEG antibodies in the protein corona could mitigate the stealth effect of PEG, leading to accelerated blood clearance and unwanted side effects.

Delivery of Immunostimulatory Cargos in Nanocarriers Enhances Anti-Tumoral Nanovaccine Efficacy

Finding a long-term cure for tumor patients still represents a major challenge. Immunotherapies offer promising therapy options, since they are designed to specifically prime the immune system against the tumor and modulate the immunosuppressive tumor microenvironment. Using nucleic-acid-based vaccines or cellular vaccines often does not achieve sufficient activation of the immune system in clinical trials. Additionally, the rapid degradation of drugs and their non-specific uptake into tissues and cells as well as their severe side effects pose a challenge. The encapsulation of immunomodulatory molecules into nanocarriers provides the opportunity of protected cargo transport and targeted uptake by antigen-presenting cells. In addition, different immunomodulatory cargos can be co-delivered, which enables versatile stimulation of the immune system, enhances anti-tumor immune responses and improves the toxicity profile of conventional chemotherapeutic agents.

Confining the Sol-Gel Reaction at the Water/Oil Interface: Creating Compartmentalized Enzymatic Nano-Organelles for Artificial Cells

Living organisms compartmentalize their catalytic reactions in membranes for increased efficiency and selectivity. To mimic the organelles of eukaryotic cells, we develop a mild approach for in situ encapsulating enzymes in aqueous-core silica nanocapsules. In order to confine the sol-gel reaction at the water/oil interface of miniemulsion, we introduce an aminosilane to the silica precursors, which serves as both catalyst and an amphiphilic anchor that electrostatically assembles with negatively charged hydrolyzed alkoxysilanes at the interface. The semi-permeable shell protects enzymes from proteolytic attack, and allows the transport of reactants and products. The enzyme-carrying nanocapsules, as synthetic nano-organelles, are able to perform cascade reactions when enveloped in a polymer vesicle, mimicking the hierarchically compartmentalized reactions in eukaryotic cells. This in situ encapsulation approach provides a versatile platform for the delivery of biomacromolecules.

Nanostructured Lipid Carriers Loaded with Dexamethasone Prevent Inflammatory Responses in Primary Non-Parenchymal Liver Cells

Liver inflammation represents a major clinical problem in a wide range of pathologies. Among the strategies to prevent liver failure, dexamethasone (DXM) has been widely used to suppress inflammatory responses. The use of nanocarriers for encapsulation and sustained release of glucocorticoids to liver cells could provide a solution to prevent severe side effects associated with systemic delivery as the conventional treatment regime. Here we describe a nanostructured lipid carrier developed to efficiently encapsulate and release DXM. This nano-formulation proved to be stable over time, did not interact in vitro with plasma opsonins, and was well tolerated by primary non-parenchymal liver cells (NPCs). Released DXM preserved its pharmacological activity, as evidenced by inducing robust anti-inflammatory responses in NPCs. Taken together, nanostructured lipid carriers may constitute a reliable platform for the delivery of DXM to treat pathologies associated with chronic liver inflammation.

Temperature, concentration, and surface modification influence the cellular uptake and the protein corona of polystyrene nanoparticles

The composition of the protein corona varies depending on several parameters and influences the cellular fate of the nanocarriers. Here, we investigated the influence of three key parameters (surface charge, temperature, and plasma concentration) on the formation and composition of the protein corona of polystyrene nanoparticles and ultimately on the cellular uptake of pre-coated nanoparticles. At a fixed temperature and concentration, the surface charge, and surfactant influence its composition. We observed that the composition of the corona formed at low temperatures (4°C) is different from that formed at physiological temperatures (37°C). At low plasma concentrations (up to 25%), the corona consists of more diverse proteins than at higher concentrations. Finally, we concluded that regardless of the nanoparticle formulation, the degree of uptake by model cancer and endothelial cells of the nanoparticles decreased when pre-coated at increasing temperature or plasma concentration. STATEMENT OF SIGNIFICANCE: Drug delivery through nanocarriers is an increasingly important concept in research and medicine. One problem in the application of nanocarriers in medicine is the protein corona that forms around the nanocarriers when they get in contact with protein-containing fluids. So far, several factors have been identified that influence the composition of the protein corona and thus the biological identity of the particles. However, lacking comparability remains between the studies because different concentrations or temperatures of the protein solutions are used. In this study we demonstrate how the incubation temperature or the concentration of plasma influences the protein corona and thus the cellular uptake of polystyrene nanoparticles.

Temperature-Responsive Nanoparticles Enable Specific Binding of Apolipoproteins from Human Plasma

Apolipoproteins are an important class of proteins because they provide a so-called stealth effect to nanoparticles. The stealth effect on nanocarriers leads to a reduced unspecific uptake into immune cells and thereby to a prolonged blood circulation time. Herein, a novel strategy to bind apolipoproteins specifically on nanoparticles by adjusting the temperature during their incubation in human plasma is presented. This specific binding, in turn, allows a control of the stealth behavior of the nanoparticles. Nanoparticles with a well-defined poly(N-isopropylacrylamide) shell are prepared, displaying a reversible change of hydrophobicity at a temperature around 32 °C. It is shown by label-free quantitative liquid chromatography-mass spectrometry that the nanoparticles are largely enriched with apolipoprotein J (clusterin) at 25 °C while they are enriched with apolipoprotein A1 and apolipoprotein E at 37 °C. The temperature-dependent protein binding is found to significantly influence the uptake of the nanoparticles by RAW264.7 and HeLa cells. The findings imply that the functionalization of nanoparticles with temperature-responsive materials is a suitable method for imparting stealth properties to nanocarriers for drug-delivery.

Current status of glucocorticoid usage in solid organ transplantation

Glucocorticoids (GCs) have been the mainstay of immunosuppressive therapy in solid organ transplantation (SOT) for decades, due to their potent effects on innate immunity and tissue protective effects. However, some SOT centers are reluctant to administer GCs long-term because of the various related side effects. This review summarizes the advantages and disadvantages of GCs in SOT. PubMed and Scopus databases were searched from 2011 to April 2021 using search syntaxes covering “transplantation” and “glucocorticoids”. GCs are used in transplant recipients, transplant donors, and organ perfusate solution to improve transplant outcomes. In SOT recipients, GCs are administered as induction and maintenance immunosuppressive therapy. GCs are also the cornerstone to treat acute antibody- and T-cell-mediated rejections. Addition of GCs to organ perfusate solution and pretreatment of transplant donors with GCs are recommended by some guidelines and protocols, to reduce ischemia-reperfusion injury peri-transplant. GCs with low bioavailability and high potency for GC receptors, such as budesonide, nanoparticle-mediated targeted delivery of GCs to specific organs, and combination use of dexamethasone with inducers of immune-regulatory cells, are new methods of GC application in SOT patients to reduce side effects or induce immune-tolerance instead of immunosuppression. Various side effects involving different non-targeted organs/tissues, such as bone, cardiovascular, neuromuscular, skin and gastrointestinal tract, have been noted for GCs. There are also potential drug-drug interactions for GCs in SOT patients.

Synthetic Silica Nano-Organelles for Regulation of Cascade Reactions in Multi-Compartmentalized Systems

In eukaryotic cells, enzymes are compartmentalized into specific organelles so that different reactions and processes can be performed efficiently and with a high degree of control. In this work, we show that these features can be artificially emulated in robust synthetic organelles constructed using an enzyme co-compartmentalization strategy. We describe an in-situ encapsulation approach that allows enzymes to be loaded into silica nanoreactors in well-defined compositions. The nanoreactors can be combined into integrated systems to produce a desired reaction outcome. We used the selective enzyme co-compartmentalization and nanoreactor integration to regulate competitive cascade reactions and to modulate the kinetics of sequential reactions involving multiple nanoreactors. Furthermore, we show that the nanoreactors can be efficiently loaded into giant polymer vesicles, resulting in multi-compartmentalized microreactors.

Costunolide Loaded in pH-Responsive Mesoporous Silica Nanoparticles for Increased Stability and an Enhanced Anti-Fibrotic Effect

Liver fibrosis remains a significant public health problem. However, few drugs have yet been validated. Costunolide (COS), as a monomeric component of the traditional Chinese medicinal herb Saussurea Lappa, has shown excellent anti-fibrotic efficacy. However, COS displays very poor aqueous solubility and poor stability in gastric juice, which greatly limits its application via an oral administration. To increase the stability, improve the dissolution rate and enhance the anti-liver fibrosis of COS, pH-responsive mesoporous silica nanoparticles (MSNs) were selected as a drug carrier. Methacrylic acid copolymer (MAC) as a pH-sensitive material was used to coat the surface of MSNs. The drug release behavior and anti-liver fibrosis effects of MSNs-COS-MAC were evaluated. The results showed that MSNs-COS-MAC prevented a release in the gastric fluid and enhanced the dissolution rate of COS in the intestinal juice. At half the dose of COS, MSNs-COS-MAC still effectively ameliorated parenchymal necrosis, bile duct proliferation and excessive collagen. MSNs-COS-MAC significantly repressed hepatic fibrogenesis by decreasing the expression of hepatic fibrogenic markers in LX-2 cells and liver tissue. These results suggest that MSNs-COS-MAC shows great promise for anti-liver fibrosis treatment.

Nanocapsules with excellent biocompatibility and stability in protein solutions

Silica nanocapsules (SiO₂NCs) are usually prepared with cationic surfactants that are not cytocompatible. Dialysis can be used to remove surfactants but leads to instability of the SiO₂NCs when they are in the presence of proteins or biological media. Herein, SiO₂NCs stabilized with a reactive surfactant are synthesized to prevent leaching upon dialysis. The SiO₂NCs show superior stability and biocompatibility compared with SiO₂NCs prepared with conventional surfactants. The SiO₂NCs can be used in self-healing materials, smart agriculture and biomedical applications.

Ultrasmall Nanocapsules Obtained by Controlling Ostwald Ripening

We describe here a method to synthesize ultrasmall nanocapsules with a diameter of 6 nm, exhibiting a well-defined core-shell morphology. Remarkably, the nanocapules are synthesized in a miniemulsion process without the need of large amounts of surfactant as commonly used in the microemulsion process. Ultrasmall nanocapsules with an oil core and a silica shell are formed by the concurrent processes of a sol-gel reaction and Ostwald ripening. Using solvents with different water solubilities and alkoxysilanes with different reactivities, we demonstrate that sizes of obtained nanocapsules depend on the ripening rate and alkoxysilane conversion rate. The method can be also used for encapsulating natural oils such as peppermint oil and limonene. This work shows that the Ostwald ripening phenomenon can be employed beneficially for the preparation of very small colloids.

Polymeric nanocapsules: A review on design and production methods for pharmaceutical purpose

Polymeric nanocapsules have extensive application potential in medical, biological, and pharmaceutical fields, and, therefore, much research has been dedicated to their production. Indeed, production protocols and the materials used are decisive for obtaining the desired nanocapsules characteristics and biological performance. In addition to that, several technological strategies have been developed in the last decade to improve processing techniques and form more valuable nanocapsules. This review provides a guide to current methods for developing polymeric nanocapsules, reporting aspects to be considered when choosing appropriate materials, and discussing different ways to produce nanocapsules for superior performances.

Novel IMB16-4 Compound Loaded into Silica Nanoparticles Exhibits Enhanced Oral Bioavailability and Increased Anti-Liver Fibrosis In Vitro

Background: Liver fibrosis, as a common and refractory disease, is challenging to treat due to the lack of effective agents worldwide. Recently, we have developed a novel compound, N-(3,4,5-trichlorophenyl)-2(3-nitrobenzenesulfonamide) benzamide (IMB16-4), which is expected to have good potential effects against liver fibrosis. However, IMB16-4 is water-insoluble and has very low bioavailability. Methods: Mesoporous silica nanoparticles (MSNs) were selected as drug carriers for the purpose of increasing the dissolution of IMB16-4, as well as improving its oral bioavailability and inhibiting liver fibrosis. The physical states of IMB16-4 and IMB16-4-MSNs were investigated using nitrogen adsorption, thermogravimetric analysis (TGA), HPLC, UV-Vis, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results: The results show that MSNs enhanced the dissolution rate of IMB16-4 significantly. IMB16-4-MSNs reduced cytotoxicity at high concentrations of IMB16-4 on human hepatic stellate cells LX-2 cells and improved oral bioavailability up to 530% compared with raw IMB16-4 on Sprague–Dawley (SD) rats. In addition, IMB16-4-MSNs repressed hepatic fibrogenesis by decreasing the expression of hepatic fibrogenic markers, including α-smooth muscle actin (α-SMA), transforming growth factor-beta (TGF-β1) and matrix metalloproteinase-2 (MMP2) in LX-2 cells. Conclusions: These results provided powerful information on the use of IMB16-4-MSNs for the treatment of liver fibrosis in the future.

Brush Conformation of Polyethylene Glycol Determines the Stealth Effect of Nanocarriers in the Low Protein Adsorption Regime

For nanocarriers with low protein affinity, we show that the interaction of nanocarriers with cells is mainly affected by the density, the molecular weight, and the conformation of polyethylene glycol (PEG) chains bound to the nanocarrier surface. We achieve a reduction of nonspecific uptake of ovalbumin nanocarriers by dendritic cells using densely packed PEG chains with a "brush" conformation instead of the collapsed "mushroom" conformation. We also control to a minor extent the dysopsonin adsorption by tailoring the conformation of attached PEG on the nanocarriers. The brush conformation of PEG leads to a stealth behavior of the nanocarriers with inhibited uptake by phagocytic cells, which is a prerequisite for successful in vivo translation of nanomedicine to achieve long blood circulation and targeted delivery. We can clearly correlate the brush conformation of PEG with inhibited phagocytic uptake of the nanocarriers. This study shows that, in addition to the surface's chemistry, the conformation of polymers controls cellular interactions of the nanocarriers.

Aqueous core and hollow silica nanocapsules for confined enzyme modules

The development of enzyme modules by coupling several enzymes in confinement is of paramount importance to artificial biological reaction systems for efficient enzymatic reactions. Silica nanocapsules are ideal candidates for loading enzymes. Aqueous core silica nanocapsules have relatively been rarely reported due to the crux of difficulty in forming dense silica shells by interfacial sol-gel reactions. Herein we suggest a one-step synthesis of hollow silica nanocapsules with an aqueous core containing enzymes via a template-free and interfacial condensation method for developing enzyme modules with coupled enzymatic reactions. As a proof-of-concept, we developed enzyme modules for three useful purposes by encapsulating a couple of enzymes: (i) development of a miniature glucose sensor, (ii) protection of living cells, and (iii) regeneration of nicotinamide adenine dinucleotides (NADs). By the modulation of enzymes using silica nanocapsules, more efficient coupled reactions, separation of enzymatic reactions from surroundings, and easy handling of several enzymes by using a single module could be achieved. Therefore, our silica nanocapsules for enzyme modules can be promoted as general platforms for developing artificial nanoreactors.

Knowledge gaps in immune response and immunotherapy involving nanomaterials: Databases and artificial intelligence for material design

Exploring the interactions between the immune system and nanomaterials (NMs) is critical for designing effective and safe NMs, but large knowledge gaps remain to be filled prior to clinical applications (e.g., immunotherapy). The lack of databases on interactions between the immune system and NMs affects the discovery of new NMs for immunotherapy. Complement activation and inhibition by NMs have been widely studied, but the general rules remain unclear. Biomimetic nanocoating to promote the clearance of NMs by the immune system is an alternative strategy for the immune response mediation of the biological corona. Immune response predictions based on NM properties can facilitate the design of NMs for immunotherapy, and artificial intelligences deserve much attention in the field. This review addresses the knowledge gaps regarding immune response and immunotherapy in relation to NMs, effective immunotherapy and material design without adverse immune responses.

Responsive Colloidosomes with Triple Function for Anticorrosion

Strategies for corrosion protection are required to prolong the life span of metallic structures used by the construction, aerospace, and transport industries. Currently, there are no coatings that can provide at the same time information about the corrosion status of the coated metal and protect the metal against corrosive species and mechanical damage. Herein, triple-functional microcarriers with functions of corrosion sensing, self-healing, and corrosion inhibition are produced and embedded in coatings to prolong the lifetime of metals and enhance the anticorrosion performance of coatings. The microcarriers are prepared by creating Pickering droplets loaded with a corrosion inhibitor and a healing agent and stabilized by silica nanocapsules containing thymol blue as corrosion sensor. The microcarriers are then embedded in a water-based polymer matrix coated on metal substrates. When the coating or metal is mechanically damaged, the healing agent is released from the droplets to hinder further corrosion of the metal. When the local pH value near the metal surface is changing by the generation of hydroxide ion due to the corrosion process, a change of color is detected as well as a release of corrosion inhibitor, leading to a significant decrease of corrosion rate of the coated metal.

Biodegradable Mesoporous Organosilica Nanosheets for Chemotherapy/Mild Thermotherapy of Cancer: Fast Internalization, High Cellular Uptake, and High Drug Loading

The choice of nanocarriers is crucial to fabricate ideal therapeutic nanoplatform in the treatment of cancer. Considering the advantages brought by the two-dimensional (2D) materials with atomic thickness in drug loading and cellular uptake, herein, novel 2D biodegradable mesoporous organosilica nanosheets (MONSs) are presented, and their application in chemotherapy/mild thermotherapy of cancer is studied by loading chemotherapy drug doxorubicin (DOX) and conjugating ultrasmall CuS nanoparticles. It is found that the loading of DOX in MONSs is as high as 859 μg/mg due to their large surface area and intermediate void structure. The release of DOX from MONSs is intelligently controlled by pH value, glutathione (GSH) concentration, and laser irradiation. Excitingly, in comparison with traditional spherical mesoporous organosilica nanoparticles, as-prepared MONSs not only show more rapid degradation but also exhibit faster internalization and higher cellular uptake efficiency due to their larger aspect ratios and unique cellular internalization approach of 2D materials. A mild thermotherapy induced by ultrasmall CuS nanoparticles can further promote the cellular uptake and improve chemotherapy efficacy. The in vitro and in vivo experimental results reveal that the theranostic nanoplatform based on degradable MONSs has excellent biocompatibility and anticancer effects. Therefore, MONSs are expected to be a competitive alternative to existing silica-based nanomaterials in antitumor treatment.