Pathogen recognition and development of particulate vaccines: does size matter?

Bionano Interactions of Organosilica Nanoparticles with Myeloid Derived Immune Cells

Investigating the interactions between nanomaterials and the cells they are likely to encounter in vivo is a critical aspect of designing nanomedicines for imaging and therapeutic applications. Immune cells such as dendritic cells, macrophages, and myeloid derived suppressor cells have a frontline role in the identification and removal of foreign materials from the body, with interactions shown to be heavily dependent on variables such as nanoparticle size, charge, and surface chemistry. Interactions such as cellular association or uptake of nanoparticles can lead to diminished functionality or rapid clearance from the body, making it critical to consider these interactions when designing and synthesizing nanomaterials for biomedical applications ranging from drug delivery to imaging and biosensing. We investigated the interactions between PEGylated organosilica nanoparticles and naturally endocytic immune cells grown from stem cells in murine bone marrow. Specifically, we varied the particle size from 60 nm up to 1000 nm and investigated the effects of size on immune cell association, activation, and maturation with these critical gatekeeper cells. These results will help inform future design parameters for in vitro and in vivo biomedical applications utilizing organosilica nanoparticles.

Poria cocos polysaccharide-loaded Alum Pickering emulsion as vaccine adjuvant to enhance immune responses

Traditional Alum adjuvants mainly elicit a Th2 humoral immune response, but fail to generate a robust Th1 cellular immune response. However, the cellular immune response is essential for vaccination against cancer and a number of chronic infectious diseases, including human immunodeficiency virus infection and tuberculosis. In our previous study, we demonstrated that the polysaccharide from Poria cocos (PCP) has the potential to serve as an immunologic stimulant, enhancing both humoral and cellular immune responses. However, this effect was only observed at high concentrations. In this study, to enhance the immune-stimulation effect of PCP and modify the type of immune response elicited by Alum adjuvant, we successfully developed a Pickering emulsion delivery system (PCP-Al-Pickering) using PCP-loaded Alhydrogel particles as the stabilizer. After optimization, the Pickering emulsion exhibited excellent storage capacity and effectively adsorbed the PCP and antigen. As an adjuvant delivery system, the PCP-Al-Pickering emulsion facilitated the antigen uptake by macrophages, increased the recruitment of cells at injection sites, improved the activation of dendritic cells in draining lymph nodes, elicited a potent and durable antibody response, and promoted the activation of CD4+ and CD8+ T cells. Importantly, the PCP-Al-Pickering emulsion adjuvant elicited a balanced Th1 and Th2 immune response, in comparison to Alum adjuvant. The PCP-Al-Pickering emulsion may serve as a safe and promising adjuvant delivery system to enhance immune responses.

Computational method for designing vaccines applied to virus-like particles (VLPs) as epitope carriers

Nonenveloped virus-like particles (VLPs) are self-assembled oligomeric structures composed of one or more proteins that originate from diverse viruses. Because these VLPs have similar antigenicity to the parental virus, they are successfully used as vaccines against cognate virus infection. Furthermore, after foreign antigenic sequences are inserted in their protein components (chimVLPs), some VLPs are also amenable to producing vaccines against pathogens other than the virus it originates from (these VLPs are named platform or epitope carrier). Designing chimVLP vaccines is challenging because the immunogenic response must be oriented against a given antigen without altering stimulant properties inherent to the VLP. An important step in this process is choosing the location of the sequence modifications because this must be performed without compromising the assembly and stability of the original VLP. Currently, many immunogenic data and computational tools can help guide the design of chimVLPs, thus reducing experimental costs and work. In this study, we analyze the structure of a novel VLP that originate from an insect virus and describe the putative regions of its three structural proteins amenable to insertion. For this purpose, we employed molecular dynamics (MD) simulations to assess chimVLP stability by comparing mutated and wild-type (WT) VLP protein trajectories. We applied this procedure to design a chimVLP that can serve as a prophylactic vaccine against the SARS-CoV-2 virus. The methodology described in this work is generally applicable for VLP-based vaccine development.

Development of α-Tocopherol Loaded PLGA Nanoparticles and Its Evaluation as a Novel Immune Adjuvant

With the continuous development of preventive and therapeutic vaccines, traditional adjuvants cannot provide sufficient immune efficacy and it is of high necessity to develop safe and effective novel nanoparticle-based vaccine adjuvants. α-Tocopherol (TOC) is commonly used in oil-emulsion adjuvant systems as an immune enhancer, yet its bioavailability is limited by poor water solubility. This study aims to develop TOC-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TOC-PLGA NPs) to explore the potential of TOC-PLGA NPs as a novel nanoparticle-immune adjuvant. TOC-PLGA NPs are prepared by a nanoprecipitation method and their physicochemical properties are characterized. It is shown that TOC-PLGA NPs are 110.8 nm, polydispersity index value of 0.042, and Zeta potential of -13.26 mV. The encapsulation efficiency and drug loading of NPs are 82.57% and 11.80%, respectively, and the cumulative release after 35 days of in vitro testing reaches 47%. Furthermore, TOC-PLGA NPs demonstrate a superior promotion effect on RAW 264.7 cell proliferation compared to PLGA NPs, being well phagocytosed and also promoting antigen uptake by macrophages. TOC-PLGA NPs can strongly upregulate the expression of co-stimulatory surface molecules and the secretion of cytokines. In conclusion, TOC-PLGA NPs can be a novel vaccine adjuvant with excellent biocompatibility and significant immune-enhancing activity.

Mucosal vaccines for viral diseases: Status and prospects

Virus-associated infectious diseases are highly detrimental to human health and animal husbandry. Among all countermeasures against infectious diseases, prophylactic vaccines, which developed through traditional or novel approaches, offer potential benefits. More recently, mucosal vaccines attract attention for their extraordinary characteristics compared to conventional parenteral vaccines, particularly for mucosal-related pathogens. Representatively, coronavirus disease 2019 (COVID-19), a respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), further accelerated the research and development efforts for mucosal vaccines by thoroughly investigating existing strategies or involving novel techniques. While several vaccine candidates achieved positive progresses, thus far, part of the current COVID-19 mucosal vaccines have shown poor performance, which underline the need for next-generation mucosal vaccines and corresponding platforms. In this review, we summarized the typical mucosal vaccines approved for humans or animals and sought to elucidate the underlying mechanisms of these successful cases. In addition, mucosal vaccines against COVID-19 that are in human clinical trials were reviewed in detail since this public health event mobilized all advanced technologies for possible solutions. Finally, the gaps in developing mucosal vaccines, potential solutions and prospects were discussed. Overall, rational application of mucosal vaccines would facilitate the establishing of mucosal immunity and block the transmission of viral diseases.

Liposomes, transfersomes and niosomes: production methods and their applications in the vaccinal field

One of the most effective strategies to fight viruses and handle health diseases is vaccination. Recent studies and current applications are moving on antigen, DNA and RNA-based vaccines to overcome the limitations related to the conventional vaccination strategies, such as low safety, necessity of multiple injection, and side effects. However, due to the instability of pristine antigen, RNA and DNA molecules, the use of nanocarriers is required. Among the different nanocarriers proposed for vaccinal applications, three types of nanovesicles were selected and analysed in this review: liposomes, transfersomes and niosomes. PubMed, Scopus and Google Scholar databases were used for searching recent papers on the most frequently used conventional and innovative methods of production of these nanovesicles. Weaknesses and limitations of conventional methods (i.e., multiple post-processing, solvent residue, batch-mode processes) can be overcome using innovative methods, in particular, the ones assisted by supercritical carbon dioxide. SuperSomes process emerged as a promising production technique of solvent-free nanovesicles, since it can be easily scaled-up, works in continuous-mode, and does not require further post-processing steps to obtain the desired products. As a result of the literature analysis, supercritical carbon dioxide assisted methods attracted a lot of interest for nanovesicles production in the vaccinal field. However, despite their numerous advantages, supercritical processes require further studies for the production of liposomes, transfersomes and niosomes with the aim of reaching well-defined technologies suitable for industrial applications and mass production of vaccines.

Size Tuning of Mesoporous Silica Adjuvant for One-Shot Vaccination with Long-Term Anti-Tumor Effect

Despite recent clinical successes in cancer immunotherapy, it remains difficult to initiate a long-term anti-tumor effect. Therefore, repeated administrations of immune-activating agents are generally required in most cases. Herein, we propose an adjuvant particle size tuning strategy to initiate a long-term anti-tumor effect by one-shot vaccination. This strategy is based on the size-dependent immunostimulation mechanism of mesoporous silica particles. Hollow mesoporous silica (HMS) nanoparticles enhance the antigen uptake with dendritic cells around the immunization site in vivo. In contrast, hierarchically porous silica (HPS) microparticles prolong cancer antigen retention and release in vivo. The size tuning of the mesoporous silica adjuvant prepared by combining both nanoparticles and microparticles demonstrates the immunological properties of both components and has a long-term anti-tumor effect after one-shot vaccination. One-shot vaccination with HMS-HPS-ovalbumin (OVA)-Poly IC (PIC, a TLR3 agonist) increases CD4+ T cell, CD8+ T cell, and CD86+ cell populations in draining lymph nodes even 4 months after vaccination, as well as effector memory CD8+ T cell and tumor-specific tetramer+CD8+ T cell populations in splenocytes. The increases in the numbers of effector memory CD8+ T cells and tumor-specific tetramer+CD8+ T cells indicate that the one-shot vaccination with HMS-HPS-OVA-PIC achieved the longest survival time after a challenge with E.G7-OVA cells among all groups. The size tuning of the mesoporous silica adjuvant shows promise for one-shot vaccination that mimics multiple clinical vaccinations in future cancer immunoadjuvant development. This study may have important implications in the long-term vaccine design of one-shot vaccinations.

Nanodiamonds: A Cutting-Edge Approach to Enhancing Biomedical Therapies and Diagnostics in Biosensing

Nanodiamonds (NDs) have garnered attention in the field of nanomedicine due to their unique properties. This review offers a comprehensive overview of NDs synthesis methods, properties, and their uses in biomedical applications. Various synthesis techniques, such as detonation, high-pressure, high-temperature, and chemical vapor deposition, offer distinct advantages in tailoring NDs' size, shape, and surface properties. Surface modification methods further enhance NDs' biocompatibility and enable the attachment of bioactive molecules, expanding their applicability in biological systems. NDs serve as promising nanocarriers for drug delivery, showcasing biocompatibility and the ability to encapsulate therapeutic agents for targeted delivery. Additionally, NDs demonstrate potential in cancer treatment through hyperthermic therapy and vaccine enhancement for improved immune responses. Functionalization of NDs facilitates their utilization in biosensors for sensitive biomolecule detection, aiding in precise diagnostics and rapid detection of infectious diseases. This review underscores the multifaceted role of NDs in advancing biomedical applications. By synthesizing NDs through various methods and modifying their surfaces, researchers can tailor their properties for specific biomedical needs. The ability of NDs to serve as efficient drug delivery vehicles holds promise for targeted therapy, while their applications in hyperthermic therapy and vaccine enhancement offer innovative approaches to cancer treatment and immunization. Furthermore, the integration of NDs into biosensors enhances diagnostic capabilities, enabling rapid and sensitive detection of biomolecules and infectious diseases. Overall, the diverse functionalities of NDs underscore their potential as valuable tools in nanomedicine, paving the way for advancements in healthcare and biotechnology.

GalNAc- or Mannose-PEG-Functionalized Polyplexes Enable Effective Lectin-Mediated DNA Delivery

A cationic, dendrimer-like oligo(aminoamide) carrier with four-arm topology based on succinoyl tetraethylene pentamine and histidines, cysteines, and N-terminal azido-lysines was screened for plasmid DNA delivery on various cell lines. The incorporated azides allow modification with various shielding agents of different polyethylene glycol (PEG) lengths and/or different ligands by copper-free click reaction, either before or after polyplex formation. Prefunctionalization was found to be advantageous over postfunctionalization in terms of nanoparticle formation, stability, and efficacy. A length of 24 ethylene oxide repetition units and prefunctionalization of ≥50% of azides per carrier promoted optimal polyplex shielding. PEG shielding resulted in drastically reduced DNA transfer, which could be successfully restored by active lectin targeting via novel GalNAc or mannose ligands, enabling enhanced receptor-mediated endocytosis of the carrier system. The involvement of the asialoglycoprotein receptor (ASGPR) in the uptake of GalNAc-functionalized polyplexes was confirmed in the ASGPR-positive hepatocarcinoma cell lines HepG2 and Huh7. Mannose-modified polyplexes showed superior cellular uptake and transfection efficacy compared to unmodified and shielded polyplexes in mannose-receptor-expressing dendritic cell-like DC2.4 cells.

Peptide nanovaccine in melanoma immunotherapy

Melanoma is an especially fatal neoplasm resistant to traditional treatment. The advancement of novel therapeutical approaches has gained attention in recent years by shedding light on the molecular mechanisms of melanoma tumorigenesis and their powerful interplay with the immune system. The presence of many mutations in melanoma cells results in the production of a varied array of antigens. These antigens can be recognized by the immune system, thereby enabling it to distinguish between tumors and healthy cells. In the context of peptide cancer vaccines, generally, they are designed based on tumor antigens that stimulate immunity through antigen-presenting cells (APCs). As naked peptides often have low potential in eliciting a desirable immune reaction, immunization with such compounds usually necessitates adjuvants and nanocarriers. Actually, nanoparticles (NPs) can provide a robust immune response to peptide-based melanoma vaccines. They improve the directing of peptide vaccines to APCs and induce the secretion of cytokines to get maximum immune response. This review provides an overview of the current knowledge of the utilization of nanotechnology in peptide vaccines emphasizing melanoma, as well as highlights the significance of physicochemical properties in determining the fate of these nanovaccines in vivo, including their drainage to lymph nodes, cellular uptake, and influence on immune responses.

Size-matching compositing nanoprobe of AIE-type gold nanocluster supramolecular nanogels wrapped by hypergravity-tailored MnO2 nanosheets for cellular glutathione detection

Compositing has been the main approach for material creation via wisely combining material components with different properties. MnO2 nanosheets (MNSs) with thin 2 D morphology are usually applied to composite molecules or nanomaterials for biosensing and bioimaging applications. However, such composition is actually structurally unmatched, albeit performance matching. Here, a series of benefits merely on the basis of structural match have been unearthed via tailoring MNSs with four sizes by synthesis under controllable hypergravity field. The classical fluorophore-quencher couple was utilized as the subject model, where the soft supramolecular nanogels based on aggregation-induced emission (AIE)-active gold nanoclusters were wrapped by MNSs of strong absorption. By comparative study of one-on-one wrapping and one-to-many encapsulation with geometrical selection of different MNSs, we found that the one-on-one wrapping model protected weakly-bonded nanogels from combination-induced distortion and strengthened nanogel networks via endowing exoskeleton. Besides, wrapping pattern and size-match significantly enhanced the quenching efficiency of MNSs towards the emissive nanogels. More importantly, the well-wrapped nanocomposites had considerable enhanced biological compatibility with much lower cytotoxicity and higher transfection capacity than the untailored MNSs composite and could serve as cellular glutathione detection.

Biologics, theranostics, and personalized medicine in drug delivery systems

The progress in human disease treatment can be greatly advanced through the implementation of nanomedicine. This approach involves targeted and cell-specific therapy, controlled drug release, personalized dosage forms, wearable drug delivery, and companion diagnostics. By integrating cutting-edge technologies with drug delivery systems, greater precision can be achieved at the tissue and cellular levels through the use of stimuli-responsive nanoparticles, and the development of electrochemical sensor systems. This precision targeting - by virtue of nanotechnology - allows for therapy to be directed specifically to affected tissues while greatly reducing side effects on healthy tissues. As such, nanomedicine has the potential to transform the treatment of conditions such as cancer, genetic diseases, and chronic illnesses by facilitating precise and cell-specific drug delivery. Additionally, personalized dosage forms and wearable devices offer the ability to tailor treatment to the unique needs of each patient, thereby increasing therapeutic effectiveness and compliance. Companion diagnostics further enable efficient monitoring of treatment response, enabling customized adjustments to the treatment plan. The question of whether all the potential therapeutic approaches outlined here are viable alternatives to current treatments is also discussed. In general, the application of nanotechnology in the field of biomedicine may provide a strong alternative to existing treatments for several reasons. In this review, we aim to present evidence that, although in early stages, fully merging advanced technology with innovative drug delivery shows promise for successful implementation across various disease areas, including cancer and genetic or chronic diseases.

pH-responsive nanogels with enhanced antioxidant and antitumor activities on drug delivery and smart drug release

pH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method. The chemical structure of chitosan derivatives was verified by 1H NMR and FT-IR techniques. Compared to hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-based nanogels, BIMIXHAC-based nanogels exhibit better drug encapsulation efficiency and loading capacity (BIMIXHAC-D-HA 91.76 %, and 32.23 %), with pH-responsive release profiles and accelerated release in vitro. The series of nanogels formed by crosslinking with three different polyanionic crosslinkers have different particle size potentials and antioxidant properties. BIMIXHAC-HA, BIMIXHAC-SA and BIMIXHAC-CMC demonstrate favorable antioxidant capability. In addition, cytotoxicity tests showed that BIMIXHAC-based nanogels have high biocompatibility. BIMIXHAC-based nanogels exhibit preferable anticancer effects on MCF-7 and A549 cells. Furthermore, the BIMIXHAC-D-HA nanogel was 2.62 times less toxic than DOX to L929 cells. These results suggest that BIMIXHAC-based nanogels can serve as pH-responsive nanoplatforms for the delivery of anticancer drugs.

Improvement of the Antioxidant and Antitumor Activities of Benzimidazole-Chitosan Quaternary Ammonium Salt on Drug Delivery Nanogels

The present study focused on the design and preparation of acid-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for a controlled, slow-release of Doxorubicin HCl (DOX.HCl). The BIMIXHAC was crosslinked with sodium tripolyphosphate (TPP) using the ion crosslinking method. The method resulted in nanogels with low polydispersity index, small particle size, and positive zeta potential values, indicating the good stability of the nanogels. Compared to hydroxypropyl trimethyl ammonium chloride chitosan-Doxorubicin HCl-sodium tripolyphosphate (HACC-D-TPP) nanogel, the benzimidazole-chitosan quaternary ammonium salt-Doxorubicin HCl-sodium tripolyphosphate (BIMIXHAC-D-TPP) nanogel show higher drug encapsulation efficiency and loading capacity (BIMIXHAC-D-TPP 93.17 ± 0.27% and 31.17 ± 0.09%), with acid-responsive release profiles and accelerated release in vitro. The hydroxypropyl trimethyl ammonium chloride chitosan-sodium tripolyphosphate (HACC-TPP), and benzimidazole-chitosan quaternary ammonium salt-sodium tripolyphosphate (BIMIXHAC-TPP) nanogels demonstrated favorable antioxidant capability. The assay of cell viability, measured by the MTT assay, revealed that nanogels led to a significant reduction in the cell viability of two cancer cells: the human lung adenocarcinoma epithelial cell line (A549) and the human breast cancer cell line (MCF-7). Furthermore, the BIMIXHAC-D-TPP nanogel was 2.96 times less toxic than DOX.HCl to the mouse fibroblast cell line (L929). It was indicated that the BIMIXHAC-based nanogel with enhanced antioxidant and antitumor activities and acidic-responsive release could serve as a potential nanocarrier.

Development of a novel squalene/α-tocopherol-based self-emulsified nanoemulsion incorporating Leishmania peptides for induction of antigen-specific immune responses

Vaccination has emerged as the most effective strategy to confront infectious diseases, among which is leishmaniasis, that threat public health. Despite laborious efforts there is still no vaccine for humans to confront leishmaniasis. Multi-epitope protein/peptide vaccines present a number of advantages, however their use along with appropriate adjuvants that may also act as antigen carriers is considered essential to overcome subunit vaccines' low immunogenicity. In the present study, a stable self-emulsified nanoemulsion was developed and double-adjuvanted with squalene and α-tocopherol. The prepared nanoemulsion droplets exhibited low cytotoxicity in a certain range of concentrations, while they were efficiently taken up by macrophages and dendritic cells in vitro as well as in vivo in secondary lymphoid organs. To further characterize nanoformulation's potent antigen delivery capability, three multi-epitope Leishmania peptides were incorporated into the nanoemulsion. Peptide encapsulation resulted in dendritic cells' functional differentiation characterized by elevated levels of maturation markers and intracellular cytokine production. Intramuscular administration of the nanoemulsion incorporating Leishmania peptides induced antigen-specific spleen cell proliferation as well as elicitation of CD4+ central memory cells, supporting the potential of the developed nanoformulation to successfully act also as an antigen delivery vehicle and thus encouraging further preclinical studies on its vaccine candidate potency.

In vitro and in vivo evaluation of immune response of poly(lactic acid) nanoparticles with different end groups

Poly(lactic acid) (PLA) has excellent properties of biodegradability and biocompatibility, which is a US Food and Drug Administration (FDA) approved biopolymer for the preparation of safe and effective vaccines, drugs, and gene delivery systems. However, there still exists a great problem whether and how the end group affects the immune response of PLA vaccines. Therefore, the aim of this study was to evaluate the in vitro and in vivo of immune response of PLA nanoparticles (NPs) with carboxyl (COOH) and ester (COOR) end groups. In vitro experiments suggested COOH NPs could promote the higher phagocytosis and activation of bone marrow dendritic cells (BMDCs) with a lower cytotoxicity. In vivo experiments showed that COOR NPs and COOH NPs could strongly elicit IgG, IgG1, and IgG2a responses both in the short and long-terms. However, the highest T cell and B cell activation, and central memory T cells response was induced by COOH NPs. In addition, the COOH NPs could significantly enhance splenocytes proliferation and cytokines secretion. Thus, the PLA with the COOH end group shows greater potential as efficient carrier materials of NPs for enhancing cellular and humoral immune responses.

In vivo evaluation of new adjuvant systems based on combination of Salmonella Typhi porins with particulate systems: Liposomes versus polymeric particles

Subunit vaccines that have weak immunogenic activity require adjuvant systems for enhancedcellular and long-acting humoral immune responses. Both lipid-based and polymeric-based particulate adjuvants have been widely investigated to induce the desired immune responses against the subunit vaccines. The adjuvant efficacy of these particulate adjuvants depends upon their physicochemical properties such as particle size, surface charge, shape and their composition. Previously, we showed in vitro effect of adjuvant systems based on combination of chitosan and Salmonella Typhi porins in microparticle or nanoparticle form, which were spherical with positive surface charge. In the present study, we have further developed an adjuvant system based on combination of porins with liposomes (cationic and neutral) and investigated the adjuvant effect of both the liposomal and polymeric systems in BALB/c mice using a model antigen, ovalbumin. Humoral immune responses were determined following priming and booster dose at 15-day intervals. In overall, IgM and IgG levels were induced in the presence of both the liposomal and polymeric adjuvant systems indicating the positive impact of combination with porins. The highest IgM levels were obtained on Day 8, and liposomal adjuvant systems were found to elicit significantly higher IgM levels compared to polymeric systems. IgG levels were increased significantly after booster, particularly more profound with the micro-sized polymeric system when compared to cationic liposomal system with nano-size. Our results demonstrated that the developed particulate systems are promising both as an adjuvant and delivery system, providing enhanced immune responses against subunit antigens, and have the potential for long-term protection.

Novel liposomal glatiramer acetate: Preparation and immunomodulatory evaluation in murine model of multiple sclerosis

The frequent administration rate required for Glatiramer acetate (GA), a first-line therapy for Multiple sclerosis (MS), poses patient compliance issues. Only a small portion of the subcutaneously administered GA is available for phagocytosis by macrophages, as most of it is hydrolyzed at its administration site or excreted renally. To unravel these hurdles, we have prepared liposomal formulations of GA through thin film-hydration method plus extrusion. The clinical and histopathological efficacy of GA-loaded liposomes were assessed in prophylactic and therapeutic manners on murine model of MS (experimental autoimmune encephalomyelitis (EAE)). The selected GA liposomal formulation showed favorable size (275 nm on average), high loading efficiency, and high macrophage localization. Moreover, administration of GA-liposomes in mice robustly suppressed the inflammatory responses and decreased the inflammatory and demyelinated lesion regions in CNS compared to the free GA with subsequent reduction of the EAE clinical score. Our study indicated that liposomal GA could be served as a reliable nanomedicine-based platform to hopefully curb MS-related aberrant autoreactive immune responses with higher efficacy, longer duration of action, fewer administration frequencies, and higher delivery rate to macrophages. This platform has the potential to be introduced as a vaccine for MS after clinical translation and merits further investigations.

Block Copolymer Encapsulation of Disarib, an Inhibitor of BCL2 for Improved Chemotherapeutic Potential

A chemical inhibitor of antiapoptotic protein, BCL2, known as Disarib, suffers poor solubility in aqueous environments; thereby limiting its potential as a chemotherapeutic agent. To overcome this limitation and enhance the therapeutic efficacy of Disarib, we have employed the encapsulation of this small molecule inhibitor within P123 copolymer matrix. Micelles were synthesized using a thin-film hydration technique, and a comprehensive analysis was undertaken to evaluate the resulting micelle properties, including morphology, particle size, intermolecular interactions, encapsulation efficiency, and in vitro release characteristics. This assessment utilized various physicochemical techniques including UV spectroscopy, FTIR spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). Disarib-loaded P123 micelle formulation denoted as P123D exhibited a well-defined particle size of approximately 29.2 nm spherical core-shell morphology. Our investigations revealed a notable encapsulation efficiency of 75%, and we observed a biphasic release pattern for the encapsulated Disarib. Furthermore, our cytotoxicity assessment of P123D micelles against mouse breast adenocarcinoma, mouse lymphoma, and human leukemic cell lines showed 40-45% increase in cytotoxicity compared with the administration of Disarib alone in the breast adenocarcinoma cell line. Enhancement in the cytotoxicity of P123D was found to be higher or limited; however, it is important to observe that the encapsulation method significantly enhanced the aqueous solubility of Disarib as it has the best solubility in dimethyl sulfoxide (DMSO) in the unencapsulated state.

Shear Stress and ROS Dual-Responsive RBC-Hitchhiking Nanoparticles for Atherosclerosis Therapy

Atherosclerosis (AS), a leading cause of death worldwide, is a chronic inflammatory disease rich in lipids and reactive oxygen species (ROS) within plaques. Therefore, lowering lipid and ROS levels is effective in treating AS and reducing AS-induced mortality. In this study, an intelligent biomimetic drug delivery system that specifically responded to both shear stress and ROS microenvironment was developed, consisting of red blood cells (RBCs) and cross-linked polyethyleneimine nanoparticles (SA PEI) loaded with a lipid-lowering drug simvastatin acid (SA), and RBCs were self-assembled with SA PEI to obtain biresponsive SA PEI@RBCs for the treatment of AS. SA PEI could achieve sustained release of SA in response to ROS and reduce ROS and lipid levels to achieve the purpose of treating AS. Shear stress model experiments showed that SA PEI@RBCs could respond to the high shear stress level (100 dynes/cm2) at plaques, realizing the desorption and enrichment of SA PEI and improving the therapeutic efficiency of SA PEI@RBCs. In vitro and in vivo experiments have confirmed that SA PEI@RBCs exhibits better in vivo safety and therapeutic efficacy than SA PEI and free SA. Therefore, shaping SA PEI@RBCs into a biomimetic drug delivery system with dual sensitivity to ROS and shear stress is an effective strategy and treatment to facilitate their delivery into plaques.

Carbopol dispersed PAA-modified UIO-66 with high colloidal stability as a combination nano-adjuvant boosts immune response and protection against pseudorabies virus in mice and pigs

Although inactivated vaccines have higher safety than live-attenuated vaccines in the control of pseudorabies virus (PRV), their protection efficacy is limited due to insufficient immunogenicity when used alone. High-performance adjuvants that can potentiate immune responses are highly desirable to improve the protection efficacy of inactivated vaccines. In this work, we have developed U@PAA-Car, a Carbopol dispersed zirconium-based metal-organic framework UIO-66 modified by polyacrylic acid (PAA), as a promising adjuvant for inactivated PRV vaccines. The U@PAA-Car has good biocompatibility, high colloidal stability, and antigen (vaccine) loading capacity. It significantly potentiates humoral and cellular immune responses over either U@PAA, Carbopol, or commercial adjuvants such as Alum and biphasic 201 by inducing a higher specific antibody titer, IgG2a/IgG1 ratio, cell cytokine secretion, and splenocyte proliferation. A protection rate of over 90% was observed in challenge tests in the model animal mice and the host animal pigs, which is much higher than that observed with commercial adjuvants. The high performance of the U@PAA-Car is attributed to antigen sustainable release at the injection site and highly efficient antigen internalization and presentation. In conclusion, this work not only demonstrates a great potential of the developed U@PAA-Car nano-adjuvant for the inactivated PRV vaccine but also gives a preliminary explanation of its action mechanism. STATEMENT OF SIGNIFICANCE: We have developed a Carbopol dispersed PAA-modified zirconium-based metal-organic framework UIO-66 (U@PAA-Car) as a promising combination nano-adjuvant for the inactivated PRV vaccine. The U@PAA-Car induced higher specific antibody titers and IgG2a/IgG1 ratio, increased cell cytokines secretion, and better splenocyte proliferation than U@PAA, Carbopol, and the commercial adjuvants Alum and biphasic 201, indicating that it induces a significant potentiation of humoral and cellular immune response. In addition, much higher protection rates were achieved with the U@PAA-Car-adjuvanted PRV vaccine in mice and pigs challenge than those observed from the commercial adjuvant groups. This work not only demonstrates the great potential of the U@PAA-Car nano-adjuvant in an inactivated PRV vaccine but also gives a preliminary explanation of its action mechanism.

Polymeric nanoparticles for DNA vaccine-based cancer immunotherapy: a review

Cancer is one of the leading causes of death and mortality in the world. There is an essential need to develop new drugs or therapeutic approaches to manage treatment-resistant cancers. Cancer immunotherapy is a type of cancer treatment that uses the power of the body's immune system to prevent, control, and eliminate cancer. One of the materials used as a vaccine in immunotherapy is DNA. The application of polymeric nanoparticles as carriers for DNA vaccines could be an effective therapeutic approach to activate immune responses and increase antigen presentation efficiency. Various materials have been used as polymeric nanoparticles, including: chitosan, poly (lactic-co-glycolic acid), Polyethylenimine, dendrimers, polypeptides, and polyesters. Application of these polymer nanoparticles has several advantages, including increased vaccine delivery, enhanced antigen presentation, adjuvant effects, and more sustainable induction of the immune system. Besides many clinical trials and commercial products that were developed based on polymer nanoparticles, there is still a need for more comprehensive studies to increase the DNA vaccine efficiency in cancer immunotherapy using this type of carrier.

Current status of nano-vaccinology in veterinary medicine science

Vaccination programmes provide a safe, effective and cost-efficient strategy for maintaining population health. In veterinary medicine, vaccination not only reduces disease within animal populations but also serves to enhance public health by targeting zoonoses. Nevertheless, for many pathogens, an effective vaccine remains elusive. Recently, nanovaccines have proved to be successful for various infectious and non-infectious diseases of animals. These novel technologies, such as virus-like particles, self-assembling proteins, polymeric nanoparticles, liposomes and virosomes, offer great potential for solving many of the vaccine production challenges. Their benefits include low immunotoxicity, antigen stability, enhanced immunogenicity, flexibility sustained release and the ability to evoke both humoral and cellular immune responses. Nanovaccines are more efficient than traditional vaccines due to ease of control and plasticity in their physio-chemical properties. They use a highly targeted immunological approach which can provide strong and long-lasting immunity. This article reviews the currently available nanovaccine technology and considers its utility for both infectious diseases and non-infectious diseases such as auto-immunity and cancer. Future research opportunities and application challenges from bench to clinical usage are also discussed.

Nanoparticles as Potent Agents for Treatment of Schistosoma Infections: A Systematic Review

Background

Schistosomiasis is an acute and chronic parasitic disease caused by blood flukes of the genus Schistosoma. The current drugs for treating schistosomiasis are associated with some side effects.

Objective

The aim of this systematic study was an overview of the treatment of diseases caused by Schistosoma based on nanoparticles.

Methods

In the present systematic research with keywords "Schistosoma", "parasitism", "anti-Schistosoma activity", "nanoparticles", "metal nanoparticles", "silver nanoparticles", "gold nanoparticles", "polymer nanoparticles", "PLGA nanoparticles", "nanoemulsions", "in vitro", and "in vivo" from five English-language databases, including ScienceDirect, europePMC, PubMed, Scopus, Ovid, and Cochrane were searched from 2000 to 2022 by 2 researchers.

Results

In the initial search, 250 studies were selected. Based on the inclusion and exclusion criteria, 27 articles were finally selected after removing duplicate, unrelated, and articles containing full text. In present article, the most nanoparticles used against Schistosoma were gold nanoparticles (22%).

Conclusions

The results indicate the high potential of various nanoparticles, including metal nanoparticles, against Schistosoma. Also, the remarkable anti-schistosomal activity of nanoparticles suggests their use in different fields to eliminate this pathogenic microorganism so that it can be used as an effective candidate in the preparation of anti-schistosomal compounds because these compounds have fewer side effects than chemical drugs. Ther Res Clin Exp. 2023; XX:XXX-XXX).

Nanoadjuvants: Promising Bioinspired and Biomimetic Approaches in Vaccine Innovation

Adjuvants are the important part of vaccine manufacturing as they elicit the vaccination effect and enhance the durability of the immune response through controlled release. In light of this, nanoadjuvants have shown unique broad spectrum advantages. As nanoparticles (NPs) based vaccines are fast-acting and better in terms of safety and usability parameters as compared to traditional vaccines, they have attracted the attention of researchers. A vaccine nanocarrier is another interesting and promising area for the development of next-generation vaccines for prophylaxis. This review looks at the various nanoadjuvants and their structure-function relationships. It compiles the state-of-art literature on numerous nanoadjuvants to help domain researchers orient their understanding and extend their endeavors in vaccines research and development.

Superior possibilities and upcoming horizons for nanoscience in COVID-19: noteworthy approach for effective diagnostics and management of SARS-CoV-2 outbreak

The outbreak of COVID-19 has caused great havoc and affected many parts of the world. It has imposed a great challenge to the medical and health fraternity with its ability to continue mutating and increasing the transmission rate. Some challenges include the availability of current knowledge of active drugs against the virus, mode of delivery of the medicaments, its diagnosis, which are relatively limited and do not suffice for further prognosis. One recently developed drug delivery system called nanoparticles is currently being utilized in combating COVID-19. This article highlights the existing methods for diagnosis of COVID-19 such as computed tomography scan, reverse transcription-polymerase chain reaction, nucleic acid sequencing, immunoassay, point-of-care test, detection from breath, nanotechnology-based bio-sensors, viral antigen detection, microfluidic device, magnetic nanosensor, magnetic resonance platform and internet-of-things biosensors. The latest detection strategy based on nanotechnology, biosensor, is said to produce satisfactory results in recognizing SARS-CoV-2 virus. It also highlights the successes in the research and development of COVID-19 treatments and vaccines that are already in use. In addition, there are a number of nanovaccines and nanomedicines currently in clinical trials that have the potential to target COVID-19.

Comparative Efficacy of Mayaro Virus-Like Particle Vaccines Produced in Insect or Mammalian Cells

Mayaro virus (MAYV) is a mosquito-transmitted alphavirus that causes often debilitating rheumatic disease in tropical Central and South America. There are currently no licensed vaccines or antiviral drugs available for MAYV disease. Here, we generated Mayaro virus-like particles (VLPs) using the scalable baculovirus-insect cell expression system. High-level secretion of MAYV VLPs in the culture fluid of Sf9 insect cells was achieved, and particles with a diameter of 64 to 70 nm were obtained after purification. We characterize a C57BL/6J adult wild-type mouse model of MAYV infection and disease and used this model to compare the immunogenicity of VLPs from insect cells with that of VLPs produced in mammalian cells. Mice received two intramuscular immunizations with 1 μg of nonadjuvanted MAYV VLPs. Potent neutralizing antibody responses were generated against the vaccine strain, BeH407, with comparable activity seen against a contemporary 2018 isolate from Brazil (BR-18), whereas neutralizing activity against chikungunya virus was marginal. Sequencing of BR-18 illustrated that this virus segregates with genotype D isolates, whereas MAYV BeH407 belongs to genotype L. The mammalian cell-derived VLPs induced higher mean neutralizing antibody titers than those produced in insect cells. Both VLP vaccines completely protected adult wild-type mice against viremia, myositis, tendonitis, and joint inflammation after MAYV challenge. IMPORTANCE Mayaro virus (MAYV) is associated with acute rheumatic disease that can be debilitating and can evolve into months of chronic arthralgia. MAYV is believed to have the potential to emerge as a tropical public health threat, especially if it develops the ability to be efficiently transmitted by urban mosquito vectors, such as Aedes aegypti and/or Aedes albopictus. Here, we describe a scalable virus-like particle vaccine against MAYV that induced neutralizing antibodies against a historical and a contemporary isolate of MAYV and protected mice against infection and disease, providing a potential new intervention for MAYV epidemic preparedness.

Emerging Trends in Lipid-Based Vaccine Delivery: A Special Focus on Developmental Strategies, Fabrication Methods, and Applications

Lipid-based vaccine delivery systems such as the conventional liposomes, virosomes, bilosomes, vesosomes, pH-fusogenic liposomes, transferosomes, immuno-liposomes, ethosomes, and lipid nanoparticles have gained a remarkable interest in vaccine delivery due to their ability to render antigens in vesicular structures, that in turn prevents its enzymatic degradation in vivo. The particulate form of lipid-based nanocarriers confers immunostimulatory potential, making them ideal antigen carriers. Facilitation in the uptake of antigen-loaded nanocarriers, by the antigen-presenting cells and its subsequent presentation through the major histocompatibility complex molecules, leads to the activation of a cascade of immune responses. Further, such nanocarriers can be tailored to achieve the desired characteristics such as charge, size, size distribution, entrapment, and site-specificity through modifications in the composition of lipids and the selection of the appropriate method of preparation. This ultimately adds to its versatility as an effective vaccine delivery carrier. The current review focuses on the various lipid-based carriers that have been investigated to date as potential vaccine delivery systems, the factors that affect their efficacy, and their various methods of preparation. The emerging trends in lipid-based mRNA vaccines and lipid-based DNA vaccines have also been summarized.

Supramolecular Polyphenol-DNA Microparticles for In Vivo Adjuvant and Antigen Co-Delivery and Immune Stimulation

DNA-based materials have attracted interest due to the tunable structure and encoded biological functionality of nucleic acids. A simple and general approach to synthesize DNA-based materials with fine control over morphology and bioactivity is important to expand their applications. Here, we report the synthesis of DNA-based particles via the supramolecular assembly of tannic acid (TA) and DNA. Uniform particles with different morphologies are obtained using a variety of DNA building blocks. The particles enable the co-delivery of cytosine-guanine adjuvant sequences and the antigen ovalbumin in model cells. Intramuscular injection of the particles in mice induces antigen-specific antibody production and T cell responses with no apparent toxicity. Protein expression in cells is shown using capsules assembled from TA and plasmid DNA. This work highlights the potential of TA as a universal material for directing the supramolecular assembly of DNA into gene and vaccine delivery platforms.

Nanovaccines for cancer immunotherapy: Focusing on complex formation between adjuvant and antigen

As an interesting cancer immunotherapy approach, cancer vaccines have been developed to deliver tumor antigens and adjuvants to antigen-presenting cells (APCs). Although the safety and easy production shifted the vaccine designing platforms toward the subunit vaccines, their efficacy is limited due to inefficient vaccine delivery. Nanotechnology-based vaccines, called nanovaccines, address the delivery limitations through co-delivery of antigens and adjuvants into lymphoid organs and APCs and their intracellular release, leading to cross-presentation of antigens and induction of potent anti-tumor immune responses. Although the nanovaccines, either as encapsulating agents or biomimetic nanoparticles, exert the desired anti-tumor activities, there is evidence that the mixing formulation to form nanocomplexes between antigens and adjuvants based on the electrostatic interactions provokes high levels of immune responses owing to Ags' availability and faster release. Here, we summarized the various platforms for developing cancer vaccines and the advantages of using delivery systems. The cancer nanovaccines, including nanoparticle-based and biomimetic-based nanovaccines, are discussed in detail. Finally, we focused on the nanocomplexes formation between antigens and adjuvants as promising cancer nanovaccine platforms.

Functional Characterization of Extracellular Vesicles from Baker's Yeast Saccharomyces Cerevisiae as a Novel Vaccine Material for Immune Cell Maturation

Extracellular vesicles (EVs) encapsulate various bioactive molecules, and much effort has been directed towards developing a novel EV-based therapy. Although recent studies reported the secretion of EVs from probiotics baker's yeast Saccharomyces cerevisiae (S. cerevisiae), their properties and functions remain obscure. The aim of this study was to clarify the usefulness of EVs from S. cerevisiae (S-EVs) as a novel vaccine material by defining their physicochemical properties and biological functions. The collected S-EVs contained β-D-glucan and showed particle sizes and zeta potentials approximately 128.8 nm and -7.39 mV, respectively. S-EVs were positive for heat shock protein 70 kDa (HSP70). These S-EVs considerably enhanced the production of proinflammatory tumor necrosis factor-α and interleukin 6 from RAW264.7 cells (mouse macrophage-like cells) and DC2.4 cells (mouse dendritic cells). The expression of maturation markers CD40, CD80 and CD86 on the surface of these immune cells incubated with S-EVs was remarkably upregulated. Immune cells endocytosed S-EVs, and toll like receptor 2 on immune cells was involved in immune activation by S-EVs. These results indicate that extracellular vesicles derived from baker's yeast Saccharomyces cerevisiae are an attractive source as a novel vaccine material for immune cells maturation.

Outer Membrane Vesicle-Coated Nanoparticle Vaccine Protects Against Acinetobacter baumannii Pneumonia and Sepsis

The highly multidrug-resistant (MDR) Gram-negative bacterial pathogen Acinetobacter baumannii is a top global health priority where an effective vaccine could protect susceptible populations and limit resistance acquisition. Outer membrane vesicles (OMVs) shed from Gram-negative bacteria are enriched with virulence factors and membrane lipids but heterogeneous in size and cargo. We report a vaccine platform combining precise and replicable nanoparticle technology with immunogenic A. baumannii OMVs (Ab-OMVs). Gold nanoparticle cores coated with Ab-OMVs (Ab-NPs) induced robust IgG titers in rabbits that enhanced human neutrophil opsonophagocytic killing and passively protected against lethal A. baumannii sepsis in mice. Active Ab-NP immunization in mice protected against sepsis and pneumonia, accompanied by B cell recruitment to draining lymph nodes, activation of dendritic cell markers, improved splenic neutrophil responses, and mitigation of proinflammatory cytokine storm. Nanoparticles are an efficient and efficacious platform for OMV vaccine delivery against A. baumannii and perhaps other high-priority MDR pathogens.

A-910823, a squalene-based emulsion adjuvant, induces T follicular helper cells and humoral immune responses via α-tocopherol component

Background

Adjuvants are chemical or biological materials that enhance the efficacy of vaccines. A-910823 is a squalene-based emulsion adjuvant used for S-268019-b, a novel vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is currently in clinical development. Published evidence has demonstrated that A-910823 can enhance the induction of neutralizing antibodies against SARS-CoV-2 in humans and animal models. However, the characteristics and mechanisms of the immune responses induced by A-910823 are not yet known.

Methods and Results

To characterize A-910823, we compared the adaptive immune response profile enhanced by A-910823 with that of other adjuvants (AddaVax, QS21, aluminum salt-based adjuvants, and empty lipid nanoparticle [eLNP]) in a murine model. Compared with other adjuvants, A-910823 enhanced humoral immune responses to an equal or greater extent following potent T follicular helper (Tfh) and germinal center B (GCB) cell induction, without inducing a strong systemic inflammatory cytokine response. Furthermore, S-268019-b containing A-910823 adjuvant produced similar results even when given as a booster dose following primary administration of a lipid nanoparticle-encapsulated messenger RNA (mRNA-LNP) vaccine. Preparation of modified A-910823 adjuvants to identify which components of A-910823 play a role in driving the adjuvant effect and detailed evaluation of the immunological characteristics induced by each adjuvant showed that the induction of humoral immunity and Tfh and GCB cell induction in A-910823 were dependent on α-tocopherol. Finally, we revealed that the recruitment of inflammatory cells to the draining lymph nodes and induction of serum cytokines and chemokines by A-910823 were also dependent on the α-tocopherol component.

Conclusions

This study demonstrates that the novel adjuvant A-910823 is capable of robust Tfh cell induction and humoral immune responses, even when given as a booster dose. The findings also emphasize that α-tocopherol drives the potent Tfh-inducing adjuvant function of A-910823. Overall, our data provide key information that may inform the future production of improved adjuvants.

High-Throughput Counting and Sizing of Therapeutic Protein Aggregates in the Nanometer Size Range by Nano-Flow Cytometry

Protein aggregation is one of the greatest challenges in biopharmaceuticals as it could decrease therapeutic efficacy, induce immunogenicity, and reduce shelf life of protein drugs. However, there lacks high-throughput methods than can count and size protein aggregates in the nanometer size range, especially for those smaller than 100 nm. Employing a laboratory-built nano-flow cytometer (nFCM) that enables light scattering detection of single silica nanoparticles as small as 24 nm with sizing resolution and accuracy comparable to those of electron microscopy, here, we report a new benchmark to analyze single protein aggregates as small as 40 nm. With an analysis rate of up to 10,000 particles/min, the size distribution and particle concentration of nanometer protein aggregates can be acquired in 2-3 min. Employing heat-induced aggregation of bovine serum albumin (BSA) at high concentrations as the model system, effects of different categories of excipients, including sugars, polyols, salts, and amino acids on the inhibition of protein aggregation were investigated. Strikingly enough, as high as 10¹⁰ to 10¹² particles/mL of protein aggregates were observed in the size range of 40 to 200 nm for therapeutic proteins of human serum albumin injection, reconstituted recombinant human interieukin-2 solution, and human immunoglobulin injection. nFCM opens a new avenue to count and size nanometer protein aggregates, suggesting its future usability in the quality assessment and formulation promotion of therapeutic proteins.

Polymeric Nanoparticles for Inhaled Vaccines

Many recent studies focus on the pulmonary delivery of vaccines as it is needle-free, safe, and effective. Inhaled vaccines enhance systemic and mucosal immunization but still faces many limitations that can be resolved using polymeric nanoparticles (PNPs). This review focuses on the use of properties of PNPs, specifically chitosan and PLGA to be used in the delivery of vaccines by inhalation. It also aims to highlight that PNPs have adjuvant properties by themselves that induce cellular and humeral immunogenicity. Further, different factors influence the behavior of PNP in vivo such as size, morphology, and charge are discussed. Finally, some of the primary challenges facing PNPs are reviewed including formulation instability, reproducibility, device-related factors, patient-related factors, and industrial-level scale-up. Herein, the most important variables of PNPs that shall be defined in any PNPs to be used for pulmonary delivery are defined. Further, this study focuses on the most popular polymers used for this purpose.

Polyethyleneimine-based immunoadjuvants for designing cancer vaccines

Despite extensive efforts to improve the effectiveness of cancer vaccines, the lack of immunogenicity remains an issue. Adjuvants are required to enhance the immunogenicity of antigens and activate the immune response. However, only a few adjuvants with acceptable toxicity have sufficient potency for use in cancer vaccines, necessitating the discovery of potent adjuvants. The most well-known cationic polymer polyethyleneimine (PEI) acts as a carrier for delivering antigens, and as an immunoadjuvant for enhancing the innate and adaptive immunity. In this review, we have summarized PEI-based adjuvants and discussed how to improve and boost the immune response to vaccines. We further focused on PEI-based adjuvants in cancer vaccines. Finally, we have proposed the potential challenges and future issues of PEI-based adjuvants to elicit the effectiveness of cancer vaccines.

Development of multistage recombinant protein vaccine formulations against toxoplasmosis using a new chitosan and porin based adjuvant system

Toxoplasmosis is a global health problem affecting both human and animal populations. The lack of effective treatment makes the development of a vaccine against toxoplasmosis one of the main goals in the management of this disease. In our study, vaccine formulations containing the multistage recombinant antigens, rBAG1 + rGRA1 were developed with a combined adjuvant system consisting of chitosan and Salmonella Typhi porins in micro (MicroAS) and nanoparticulate (NanoAS) forms. BALB/c mice were immunized intraperitoneally with vaccine formulations two times at three-week intervals. Three weeks after the second vaccination, mice were challenged with 7-8 live tissue cysts of the virulent T. gondii PRU strain by oral gavage. Higher cellular uptake by macrophages and enhanced cellular (IFN-γ and I-4 in stimulated spleen cells) and humoral (IgG, IgG1, IgG2a) responses were obtained with the adjuvanted formulation, higher with microsystem when compared to that of nanosystem. Microsystem was found to stimulate Th1-polarized immune responses, whereasnon-adjuvanted antigens stimulated Th2-polarized immune response. The highest survival rate and reduction in cysts numbers and T. gondii DNA were obtained with the adjuvanted antigens.Our study showed that adjuvanted multistage recombinant vaccine systems increase theimmune response with strong protection againstT. gondii, more profoundly in microparticulate form.

Nano toolbox in immune modulation and nanovaccines

Despite the great success of vaccines over two centuries, the conventional strategy is based on attenuated/altered microorganisms. However, this is not effective for all microbes and often fails to elicit a protective immune response, and sometimes poses unexpected safety risks. The expanding nano toolbox may overcome some of the roadblocks in vaccine development given the plethora of unique nanoparticle (NP)-based platforms that can successfully induce specific immune responses leading to exciting and novel solutions. Nanovaccines necessitate a thorough understanding of the immunostimulatory effect of these nanotools. We present a comprehensive description of strategies in which nanotools have been used to elicit an immune response and provide a perspective on how nanotechnology can lead to future personalized nanovaccines.

Think like a Virus: Toward Improving Nanovaccine Development against SARS-CoV-2

There is no doubt that infectious diseases present global impact on the economy, society, health, mental state, and even political aspects, causing a long-lasting dent, and the situation will surely worsen if and when the viral spread becomes out of control, as seen during the still ongoing coronavirus disease 2019 (COVID-19) pandemic. Despite the considerable achievements made in viral prevention and treatment, there are still significant challenges that can be overcome through careful understanding of the viral mechanism of action to establish common ground for innovating new preventative and treatment strategies. Viruses can be regarded as devil nanomachines, and one innovative approach to face and stop the spread of viral infections is the development of nanoparticles that can act similar to them as drug/vaccine carriers. Moreover, we can use the properties that different viruses have in designing nanoparticles that reassemble the virus conformational structures but that do not present the detrimental threats to human health that native viruses possess. This review discusses the current preventative strategies (i.e., vaccination) used in facing viral infections and the associated limitations, highlighting the importance of innovating new approaches to face viral infectious diseases and discussing the current nanoapplications in vaccine development and the challenges that still face the nanovaccine field.

A novel CKIP-1 SiRNA slow-release coating on porous titanium implants for enhanced osseointegration

Osseointegration between implants and bone tissue lays the foundation for the long-term stability of implants. The incorporation of a porous structure and local slow release of siRNA to silence casein kinase-2 interacting protein-1 (CKIP-1), a downregulator of bone formation, is expected to promote osseointegration. Here, porous implants with a porous outer layer and dense inner core were prepared by metal coinjection molding (MIM). Mg-doped calcium phosphate nanoparticles (CaPNPs)-grafted arginine-glycine-aspartate cell adhesion sequence (RGD) and transcribed activator (TAT) (MCPRT)/CKIP-1 siRNA complex and polylysine (PLL) were coated onto the surface of the porous implants by layer-by-layer (LBL) self-deposition. The in vitro results showed that the MCPRT-siRNA coating promoted MG63 cell adhesion and proliferation, enhanced the protein expressions (ALP and OC) and bone formation-related gene expression (OPN, OC and COL-1α) in vitro. The in vivo results demonstrated that the porous structure enhanced bone ingrowth and that the local slow release of MCPRT-siRNA accelerated new bone formation at the early stage. The porous structure coupled with local CKIP-1 siRNA delivery constitutes a promising approach to achieve faster and stronger osseointegration for dental implants.

Emerging vaccine nanotechnology: From defense against infection to sniping cancer

Looking retrospectively at the development of humanity, vaccination is an unprecedented medical landmark that saves lives by harnessing the human immune system. During the ongoing coronavirus disease 2019 (COVID-19) pandemic, vaccination is still the most effective defense modality. The successful clinical application of the lipid nanoparticle-based Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines highlights promising future of nanotechnology in vaccine development. Compared with conventional vaccines, nanovaccines are supposed to have advantages in lymph node accumulation, antigen assembly, and antigen presentation; they also have, unique pathogen biomimicry properties because of well-organized combination of multiple immune factors. Beyond infectious diseases, vaccine nanotechnology also exhibits considerable potential for cancer treatment. The ultimate goal of cancer vaccines is to fully mobilize the potency of the immune system as a living therapeutic to recognize tumor antigens and eliminate tumor cells, and nanotechnologies have the requisite properties to realize this goal. In this review, we summarize the recent advances in vaccine nanotechnology from infectious disease prevention to cancer immunotherapy and highlight the different types of materials, mechanisms, administration methods, as well as future perspectives.

Assessing the Efficacy of a Tumor Nanovaccine and Artificial Antigen Presenting Cell-Based System as a Combination Therapy in a Mouse Model of Melanoma

Tumor cell lysate (TCL)-based vaccines contain a large number of tumor-specific and related antigens, albeit at low levels, that require active transfer and presentation by antigen-presenting cells (APCs) in vivo, which stimulate a weak immune response. The artificial APC (aAPC) system presented herein is a cell-based therapeutic system that can significantly enhance the immune response compared to TCL-based vaccines. This study combines these two treatment strategies to assess their in vitro and in vivo effects. We successfully prepared TCL-poly(lactic-co-glycolic acid)-PEI (TPP) and demonstrated that it was phagocytosed by the APCs and enhanced the maturation of DCs in vitro. The use of TPP in combination with the aAPCs resulted in better antitumor effects compared to the individual therapies. The combination therapy induced a higher proportion of CD4+ T, CD8+ T, and TRP2180–188-specific CD8+ T cells in comparison with the individual therapies. Additionally, the combination therapy enhanced the in vitro proliferation activity; greater inhibited regulatory T cells; and promoted inflammatory cytokine secretion, while reduced the production of inhibitory cytokines. In conclusion, the combination therapy consisting of the TPP tumor nanovaccine and the aAPC system enabled a broader immune response and achieve better antitumor effects compared to treatment with the individual therapies.

Preparation of Doxorubicin-Loaded Carboxymethyl-β-Cyclodextrin/Chitosan Nanoparticles with Antioxidant, Antitumor Activities and pH-Sensitive Release

In this study, chitosan nanoparticles (HF-CD NPs) were synthesized by an ionic gelation method using negatively charged carboxymethyl-β-cyclodextrin and positively charged 2-hydroxypropyltrimethyl ammonium chloride chitosan bearing folic acid. The surface morphology of HF-CD NPs was spherical or oval, and they possessed relatively small particle size (192 ± 8 nm) and positive zeta potential (+20 ± 2 mV). Meanwhile, doxorubicin (Dox) was selected as model drug to investigate the prepared nanoparticles’ potential to serve as a drug delivery carrier. The drug loading efficiency of drug-loaded nanoparticles (HF-Dox-CD NPs) was 31.25%. In vitro release profiles showed that Dox release of nanoparticles represented a pH-sensitive sustained and controlled release characteristic. At the same time, the antioxidant activity of nanoparticles was measured, and chitosan nanoparticles possessed good antioxidant activity and could inhibit the lipid peroxidation inside the cell and avoid material infection. Notably, CCK-8 assay testified that the nanoparticles were safe drug carriers and significantly enhanced the antitumor activity of Dox. The nanoparticles possessed good antioxidant activity, pH-sensitive sustained controlled release, enhanced antitumor activity, and could be expected to serve as a drug carrier in future with broad application prospects.

Aggregates Associated with Instability of Antibodies during Aerosolization Induce Adverse Immunological Effects

Background: Immunogenicity refers to the inherent ability of a molecule to stimulate an immune response. Aggregates are one of the major risk factors for the undesired immunogenicity of therapeutic antibodies (Ab) and may ultimately result in immune-mediated adverse effects. For Ab delivered by inhalation, it is necessary to consider the interaction between aggregates resulting from the instability of the Ab during aerosolization and the lung mucosa. The aim of this study was to determine the impact of aggregates produced during aerosolization of therapeutic Ab on the immune system. Methods: Human and murine immunoglobulin G (IgG) were aerosolized using a clinically-relevant nebulizer and their immunogenic potency was assessed, both in vitro using a standard human monocyte-derived dendritic cell (MoDC) reporter assay and in vivo in immune cells in the airway compartment, lung parenchyma and spleen of healthy C57BL/6 mice after pulmonary administration. Results: IgG aggregates, produced during nebulization, induced a dose-dependent activation of MoDC characterized by the enhanced production of cytokines and expression of co-stimulatory markers. Interestingly, in vivo administration of high amounts of nebulization-mediated IgG aggregates resulted in a profound and sustained local and systemic depletion of immune cells, which was attributable to cell death. This cytotoxic effect was observed when nebulized IgG was administered locally in the airways as compared to a systemic administration but was mitigated by improving IgG stability during nebulization, through the addition of polysorbates to the formulation. Conclusion: Although inhalation delivery represents an attractive alternative route for delivering Ab to treat respiratory infections, our findings indicate that it is critical to prevent IgG aggregation during the nebulization process to avoid pro-inflammatory and cytotoxic effects. The optimization of Ab formulation can mitigate adverse effects induced by nebulization.

Microplastic consumption induces inflammatory signatures in the colon and prolongs a viral arthritis

Global microplastic (MP) contamination and the effects on the environment are well described. However, the potential for MP consumption to affect human health remains controversial. Mice consuming ≈80 μg/kg/day of 1 μm polystyrene MPs via their drinking water showed no weight loss, nor were MPs detected in internal organs. The microbiome was also not significantly changed. MP consumption did lead to small transcriptional changes in the colon suggesting plasma membrane perturbations and mild inflammation. Mice were challenged with the arthritogenic chikungunya virus, with MP consumption leading to a significantly prolonged arthritic foot swelling that was associated with elevated Th1, NK cell and neutrophil signatures. Immunohistochemistry also showed a significant increase in the ratio of neutrophils to monocyte/macrophages. The picture that emerges is reminiscent of enteropathic arthritis, whereby perturbations in the colon are thought to activate innate lymphoid cells that can inter alia migrate to joint tissues to promote inflammation.

DENV-Mimetic Polymersome Nanoparticles Bearing Multi-Epitope Lipopeptides Antigen as the Next-Generation Dengue Vaccine

Dengue remains a severe threat to public health. The safety and efficacy of the licensed dengue vaccine is not clinically satisfactory, which necessitate the need of new approach in designing an effective dengue vaccine without eliciting adverse reaction. Herein, we have designed a lipidated multi-epitope peptide vaccine (LipoDV) that can elicit highly targeted humoral and cell-mediated immune responses. To improve its immunogenicity, LipoDV was presented on the surface of MPLA-functionalized polymersome nanoparticles (PNs-LipoDV-MPLA). The as-constructed vaccine delivery platform resembles the structural morphology of DENV owing to its spherical nanoscale particle size and surface immunostimulatory properties given by LipoDV and MPLA that emulating the functional role of DENV E and prM/M proteins respectively. A proof-of-concept study demonstrated that BALB/c mice immunized with PNs-LipoDV-MPLA induced a stronger antigen-specific antibody response with an enhanced cell-mediated immunity as characterized by the elevated IFN-γ secretion in comparison to other tested vaccine candidates which possess a lesser structural trait of DENV. The DENV-mimicking nanoparticles vaccine exhibited negligible toxicity as analyzed by hemolytic test, MTT assay, histopathological examination and abnormal toxicity test on immunized mice. Collectively, our study provides a strong foundation in designing an effective peptide-based vaccine delivery platform against DENV infection.

Enhancing Immune Responses to a DNA Vaccine Encoding Toxoplasma gondii GRA7 Using Calcium Phosphate Nanoparticles as an Adjuvant

Toxoplasma gondii infects almost all warm-blooded animals, including humans. DNA vaccines are an effective strategy against T. gondii infection, but these vaccines have often been poorly immunogenic due to the poor distribution of plasmids or degradation by lysosomes. It is necessary to evaluate the antigen delivery system for optimal vaccination strategy. Nanoparticles (NPs) have been shown to modulate and enhance the cellular humoral immune response. Here, we studied the immunological properties of calcium phosphate nanoparticles (CaPNs) as nanoadjuvants to enhance the protective effect of T. gondii dense granule protein (GRA7). BALB/c mice were injected three times and then challenged with T. gondii RH strain tachyzoites. Mice vaccinated with GRA7-pEGFP-C2+nano-adjuvant (CaPNs) showed a strong cellular immune response, as monitored by elevated levels of anti-T. gondii-specific immunoglobulin G (IgG), a higher IgG2a-to-IgG1 ratio, elevated interleukin (IL)-12 and interferon (IFN)-γ production, and low IL-4 levels. We found that a significantly higher level of splenocyte proliferation was induced by GRA7-pEGFP-C2+nano-adjuvant (CaPNs) immunization, and a significantly prolonged survival time and decreased parasite burden were observed in vaccine-immunized mice. These data indicated that CaPN-based immunization with T. gondii GRA7 is a promising approach to improve vaccination.

Effective improvements to the live-attenuated Newcastle disease virus vaccine by polyethylenimine-based biomimetic silicification

Live and killed vaccines impart a significant role in preventing of Newcastle disease (ND) in China. Vaccine efficacy could be ameliorated by improving vaccine-induced cellular immunity and antibody persistency. Previous studies substantiated the potency of silicon dioxide (SiO₂) in the control-release of drugs and as a vaccine adjuvant, and polyethylenimine (PEI) merits as a mucosal adjuvanticity with electro-positivity. The present study employed SiO₂ and PEI to prepare biomimetic silicon mineralized nanoparticle G7M@SiO₂-PEI and microparticle (SiO₂ + PEI)@G7M vaccines of G7M, a candidate for live attenuated vaccine of genotype VII Newcastle disease virus (NDV). The zeta potential experiment confirmed the significant increase in the average zeta potential of the nanoparticle G7M@SiO₂-PEI and microparticle (SiO₂ + PEI)@G7M relative to G7M before mineralization. The results of RT-qPCR revealed more than 99% mineralization efficiency of the G7M@SiO₂-PEI and (SiO₂ + PEI)@G7M. The morphology detected by transmission electron microscopy reported that the diameters of G7M@SiO₂-PEI were similar to those of G7M, while for (SiO₂ + PEI)@G7M, it was about five times larger than that of G7M. Silicon was detected on the surface of both mineralization particles, except for G7M, as observed from the elemental distribution detected by elemental mapping and energy dispersive X-ray spectrogram. Indirect immunofluorescence assays validated that mineralization virus have replicated ability in BHK-21F cells. In vivo experiments revealed higher than 5.50 log₂ of antibody in nanoparticles G7M@SiO₂-PEI group until 10-week post-vaccination, and significant proliferation of antigen-specific CD3⁺CD4⁺ in nanoparticles G7M@SiO₂-PEI immunized group corroborated improved cellular immune responses. Vaccines provided full protection to the immunized chickens, whereas all the chickens receiving mock immunizations succumbed to the disease. Overall, our study concluded the efficacy of biomimetic mineralization of live attenuated vaccine in nanoparticles to improve humoral and cellular immune responses.