Magnetic Nanovectors for the Development of DNA Blood-Stage Malaria Vaccines

Potential of nanoformulations in malaria treatment

Malaria is caused by the protozoan Plasmodium sp and affects millions of people worldwide. Its clinical form ranges from asymptomatic to potentially fatal and severe. Current treatments include single drugs such as chloroquine, lumefantrine, primaquine, or in combination with artemisinin or its derivatives. Resistance to antimalarial drugs has increased; therefore, there is an urgent need to diversify therapeutic approaches. The disease cycle is influenced by biological, social, and anthropological factors. This longevity and complexity contributes to the records of drug resistance, where further studies and proposals for new therapeutic formulations are needed for successful treatment of malaria. Nanotechnology is promising for drug development. Preclinical formulations with antimalarial agents have shown positive results, but only a few have progressed to clinical phase. Therefore, studies focusing on the development and evaluation of antimalarial formulations should be encouraged because of their enormous therapeutic potential.

Design of Personalized Neoantigen RNA Vaccines Against Cancer Based on Next-Generation Sequencing Data

The good clinical results of immune checkpoint inhibitors (ICIs) in recent cancer therapy and the success of RNA vaccines against SARS-nCoV2 have provided important lessons to the scientific community. On the one hand, the efficacy of ICI depends on the number and immunogenicity of tumor neoantigens (TNAs) which unfortunately are not abundantly expressed in many cancer subtypes. On the other hand, novel RNA vaccines have significantly improved both the stability and immunogenicity of mRNA and its efficient delivery, this way overcoming past technique limitations and also allowing a quick vaccine development at the same time. These two facts together have triggered a resurgence of therapeutic cancer vaccines which can be designed to include individual TNAs and be synthesized in a timeframe short enough to be suitable for the tailored treatment of a given cancer patient.In this chapter, we explain the pipeline for the synthesis of TNA-carrying RNA vaccines which encompasses several steps such as individual tumor next-generation sequencing (NGS), selection of immunogenic TNAs, nucleic acid synthesis, drug delivery systems, and immunogenicity assessment, all of each step comprising different alternatives and variations which will be discussed.

Engineered Nanodelivery Systems to Improve DNA Vaccine Technologies

DNA vaccines offer a flexible and versatile platform to treat innumerable diseases due to the ease of manipulating vaccine targets simply by altering the gene sequences encoded in the plasmid DNA delivered. The DNA vaccines elicit potent humoral and cell-mediated responses and provide a promising method for treating rapidly mutating and evasive diseases such as cancer and human immunodeficiency viruses. Although this vaccine technology has been available for decades, there is no DNA vaccine that has been used in bed-side application to date. The main challenge that hinders the progress of DNA vaccines and limits their clinical application is the delivery hurdles to targeted immune cells, which obstructs the stimulation of robust antigen-specific immune responses in humans. In this updated review, we discuss various nanodelivery systems that improve DNA vaccine technologies to enhance the immunological response against target diseases. We also provide possible perspectives on how we can bring this exciting vaccine technology to bedside applications.

Nanoparticle systems for cancer vaccine

As effective tools for public health, vaccines prevent disease by priming the body's adaptive and innate immune responses against an infection. Due to advances in understanding cancers and their relationship with the immune system, there is a growing interest in priming host immune defenses for a targeted and complete antitumor response. Nanoparticle systems have shown to be promising tools for effective antigen delivery as vaccines and/or for potentiating immune response as adjuvants. Here, we highlight relevant physiological processes involved in vaccine delivery, review recent advances in the use of nanoparticle systems for vaccines and discuss pertinent challenges to viably translate nanoparticle-based vaccines and adjuvants for public use.

Enhanced Th1/Th2 mixed immune responses elicited by polyethyleneimine adjuvanted influenza A (H7N9) antigen HA1-2 in chickens

Influenza A (H7N9) viruses have caused severe human infections and deaths every year in China since 2013. To reduce the risk of human infection and prevent a new influenza pandemic, there is a pressing need to develop safe and effective anti-H7N9 vaccines for poultry. Polyethyleneimine (PEI) is an organic polycation used extensively as a transfection reagent for decades. Although the adjuvant potential of PEI is well studied in mammals, its applicability and immune characteristics to avian species are still very rare. Here, to investigate the adjuvant activity of PEI, we analyzed the immune responses in chicken peripheral blood mononuclear cells in vitro. PEI significantly upregulated the expression of immune-related cytokines (IFN-γ, IL-2, IL-4, IL-6, IL-18, and IL-1β) and chemokines (CXCLi1, CXCLi2, MIP-1β, and MCP-3), suggesting that PEI promoted immune responses of avian cells. We also assessed the in vivo immune responses to PEI in a chicken model. After the second and third vaccinations, significantly higher IgG titers were observed in the chickens immunized with HA1-2+PEI than that of HA1-2 alone. The HA1-2+PEI group also increased percentages of CD4+ and CD8+ T cells and improved PBMC proliferation. The significantly upregulated IFN-γ and IL-4 levels of splenocytes from HA1-2+PEI vaccinated chickens further indicated that PEI promoted a Th1/Th2 mixed immune responses. This study not only demonstrates the adjuvant potential of PEI when co-administered with influenza H7N9 antigen HA1-2 in chickens, but also supports the use of PEI as a versatile systemic adjuvant platform in poultry.

Evaluation of the Ability of Nanostructured PEI-Coated Iron Oxide Nanoparticles to Incorporate Cisplatin during Synthesis

Nanoparticles (NPs) have a high potential for biological applications as they can be used as carriers for the controlled release of bioactive factors. Here we focused on poly(ethylenimine) (PEI)-coated iron oxide hybrid NPs obtained by hydrothermal synthesis in high pressure conditions and evaluated their behavior in culture medium in the presence or absence of cells, as well as their ability to incorporate antitumor drug cisplatin. Our results showed that the hydrothermal conditions used for Fe-PEI NPs synthesis allowed the incorporation of cisplatin, which even increased its anti-tumor effects. Furthermore, the commonly occurring phenomenon of NPs aggregation in culture medium was exploited for further entrapment of other active molecules, such as the fluorescent dye DiI and valinomycin. The molecules bound to NPs during synthesis or during aggregation process were delivered inside various cells after in vitro and in vivo direct contact between cells and NPs and their biological activity was preserved, thus supporting the therapeutic value of Fe-PEI NPs as drug delivery tools.

Tuning Properties of Iron Oxide Nanoparticles in Aqueous Synthesis without Ligands to Improve MRI Relaxivity and SAR

Aqueous synthesis without ligands of iron oxide nanoparticles (IONPs) with exceptional properties still remains an open issue, because of the challenge to control simultaneously numerous properties of the IONPs in these rigorous settings. To solve this, it is necessary to correlate the synthesis process with their properties, but this correlation is until now not well understood. Here, we study and correlate the structure, crystallinity, morphology, as well as magnetic, relaxometric and heating properties of IONPs obtained for different durations of the hydrothermal treatment that correspond to the different growth stages of IONPs upon initial co-precipitation in aqueous environment without ligands. We find that their properties were different for IONPs with comparable diameters. Specifically, by controlling the growth of IONPs from primary to secondary particles firstly by colloidal and then also by magnetic interactions, we control their crystallinity from monocrystalline to polycrystalline IONPs, respectively. Surface energy minimization in the aqueous environment along with low temperature treatment is used to favor nearly defect-free IONPs featuring superior properties, such as high saturation magnetization, magnetic volume, surface crystallinity, the transversal magnetic resonance imaging (MRI) relaxivity (up to r₂ = 1189 mM⁻¹·s⁻¹ and r₂/r₁ = 195) and specific absorption rate, SAR (up to 1225.1 W·g_Fe⁻¹).

Polyethylenimine-based micro/nanoparticles as vaccine adjuvants

Vaccines have shown great success in treating and preventing tumors and infections, while adjuvants are always demanded to ensure potent immune responses. Polyethylenimine (PEI), as one of the well-studied cationic polymers, has been used as a transfection reagent for decades. However, increasing evidence has shown that PEI-based particles are also capable of acting as adjuvants. In this paper, we briefly review the physicochemical properties and the broad applications of PEI in different fields, and elaborate on the intracellular processes of PEI-based vaccines. In addition, we sum up the proof of their in vivo and clinical applications. We also highlight some mechanisms proposed for the intrinsic immunoactivation function of PEI, followed by the challenges and future perspectives of the applications of PEI in the vaccines, as well as some strategies to elicit the desirable immune responses.

Release of Doxorubicin by a Folate-Grafted, Chitosan-Coated Magnetic Nanoparticle

In clinical tumor therapy, chemotherapeutic routes have caused severe side effects; current delivery methods are unsatisfactory. Successful design of a remotely folate (FA)-grafted chitosan (CS)-coated magnetic nanoparticle (MNP) with low toxicity, has been achieved. A chemotherapeutic drug such as doxorubicin (DOX), is loaded in the MNP-based matrix (FA-grafted CS-DOX-_TPP-MNP), which is coated by an activated target tumor molecule of FA-grafted CS biopolymer with the inclusion of tripolyphosphate (TPP) as a linker. The resultant nano-complexes exhibited random aggregates (~240 nm) and zeta potential (−24.9 mV). In vivo experiments using athymic BALB/c nude mice with human glioblastoma U87 cells in a subcutaneous tumor model revealed that magnetic guidance of FA-grafted CS-DOX-_TPP-MNP, injected via the tail vein, significantly decreased tumor growth. This manuscript demonstrates the feasibility of magnetizing control of FA-grafted CS-DOX-_TPP-MNP to enhance the localization of drug release.