Nano-vesicles based on phospholipid-like amphiphilic polyphosphazenes to orally deliver ovalbumin antigen for evoking anti-tumor immune response

Harnessing Bacterial Membrane Components for Tumor Vaccines: Strategies and Perspectives

Tumor vaccines stand at the vanguard of tumor immunotherapy, demonstrating significant potential and promise in recent years. While tumor vaccines have achieved breakthroughs in the treatment of cancer, they still encounter numerous challenges, including improving the immunogenicity of vaccines and expanding the scope of vaccine application. As natural immune activators, bacterial components offer inherent advantages in tumor vaccines. Bacterial membrane components, with their safer profile, easy extraction, purification, and engineering, along with their diverse array of immune components, activate the immune system and improve tumor vaccine efficacy. This review systematically summarizes the mechanism of action and therapeutic effects of bacterial membranes and its derivatives (including bacterial membrane vesicles and hybrid membrane biomaterials) in tumor vaccines. Subsequently, the authors delve into the preparation and advantages of tumor vaccines based on bacterial membranes and hybrid membrane biomaterials. Following this, the immune effects of tumor vaccines based on bacterial outer membrane vesicles are elucidated, and their mechanisms are explained. Moreover, their advantages in tumor combination therapy are analyzed. Last, the challenges and trends in this field are discussed. This comprehensive analysis aims to offer a more informed reference and scientific foundation for the design and implementation of bacterial membrane-based tumor vaccines.

Polymersomes for Therapeutic Protein and Peptide Delivery: Towards Better Loading Properties

Therapeutics based on proteins and peptides have profoundly transformed the landscape of treatment for diseases, from diabetes mellitus to cancers, yet the short half-life and low bioavailability of therapeutic proteins and peptides hinder their wide applications. To break through this bottleneck, biomolecules-loaded polymersomes with strong adjustability and versatility have attracted more and more attentions recently. Loading proteins or peptides into polymersomes is the first but extremely important step towards developing high-quality formulation products. However, increasing protein and peptide loading content is quite challenging due to the inherent nature of self-assembled vesicle formation mechanism and physiochemical characteristics of biomacromolecules. This review highlights the potential of polymersomes as the next-generation therapeutic proteins and peptides carrier and emphatically introduces novel approaches and recent progress to achieve satisfactory encapsulation capability of polymersomes for proteins and peptides. On the one hand, with the help of intermolecular interactions, such as electrostatic, lipid-protein, and hydrophobic interactions, the drug loading could be significantly improved. On the other hand, loading improvement could be attained through innovation of preparation methods, ranging from modified traditional film hydration techniques to the novel phase-guided assembly method.

Mucosal vaccination: onward and upward

INTRODUCTION

The unique mucosal immune system allows the generation of robust protective immune responses at the front line of pathogen encounters. The needle-free delivery route and cold chain-free logistic requirements also provide additional advantages in ease and economy. However, the development of mucosal vaccines faces several challenges, and only a handful of mucosal vaccines are currently licensed. These vaccines are all in the form of live attenuated or inactivated whole organisms, whereas no subunit-based mucosal vaccine is available.

AREAS COVERED

The selection of antigen, delivery vehicle, route and adjuvants for mucosal vaccination are highly important. This is particularly crucial for subunit vaccines, as they often fail to elicit strong immune responses. Emerging research is providing new insights into the biological and immunological uniqueness of mucosal tissues. However, many aspects of the mucosal immunology still await to be investigated.

EXPERT OPINION

This article provides an overview of the current understanding of mucosal vaccination and discusses the remaining knowledge gaps. We emphasize that because of the potential benefits mucosal vaccines can bring from the biomedical, social and economic standpoints, the unmet goal to achieve mucosal vaccine success is worth the effort.

Polyphosphazene-Based Biomaterials for Biomedical Applications

Recently, synthetic polymers have attracted great interest in the field of biomedical science. Among these, polyphosphazenes (PPZs) are regarded as one of the most promising materials, due to their structural flexibility and biodegradability compared to other materials. PPZs have been developed through numerous studies. In particular, multi-functionalized PPZs have been proven to be potential biomaterials in various forms, such as nanoparticles (NPs) and hydrogels, through the introduction of various functional groups. Thus, PPZs have been applied for the delivery of therapeutic molecules (low molecular weight drugs, genes and proteins), bioimaging, phototherapy, bone regeneration, dental liners, modifiers and medical devices. The main goal of the present review is to highlight the recent and the most notable existing PPZ-based biomaterials for aforementioned applications, with future perspectives in mind.

Emerging Phospholipid Nanobiomaterials for Biomedical Applications to Lab-on-a-Chip, Drug Delivery, and Cellular Engineering

The design of advanced nanobiomaterials to improve analytical accuracy and therapeutic efficacy has become an important prerequisite for the development of innovative nanomedicines. Recently, phospholipid nanobiomaterials including 2-methacryloyloxyethyl phosphorylcholine (MPC) have attracted great attention with remarkable characteristics such as resistance to nonspecific protein adsorption and cell adhesion for various biomedical applications. Despite many recent reports, there is a lack of comprehensive review on the phospholipid nanobiomaterials from synthesis to diagnostic and therapeutic applications. Here, we review the synthesis and characterization of phospholipid nanobiomaterials focusing on MPC polymers and highlight their attractive potentials for applications in micro/nanofabricated fluidic devices, biosensors, lab-on-a-chip, drug delivery systems (DDSs), COVID-19 potential usages for early diagnosis and even treatment, and artificial extracellular matrix scaffolds for cellular engineering.

Advancedoral vaccine delivery strategies for improving the immunity

Infectious diseases continue to inflict a high global disease burden. The consensus is that vaccination is the most effective option against infectious diseases. Oral vaccines have unique advantages in the prevention of global pandemics due to their ease of use, high compliance, low cost, and the ability to induce both systemic and mucosal immune responses. However, challenges of adapting vaccines for oral administration remain significant. Foremost among these are enzymatic and pH-dependent degradation of antigens in the stomach and intestines, the low permeability of mucus barrier, the nonspecific uptake of antigens at the intestinal mucosal site, and the immune suppression result from the elusive immune tolerance mechanisms. Innovative delivery techniques promise great potential for improving the flexibility and efficiency of oral vaccines. A better understanding of the delivery approaches and the immunological mechanisms of oral vaccine delivery systems may provide new scientific insight and tools for developing the next-generation oral vaccine. Here, an overview of the advanced technologies in the field of oral vaccination is proposed, including mucus-penetrating nanoparticle (NP), mucoadhesive delivery vehicles, targeting antigen-presenting cell (APC) nanocarriers and enhanced paracellular delivery strategies and so on. Meanwhile, the mechanisms of delivery vectors interact with mucosal barriers are discussed.

Biomaterial nanocarrier-driven mechanisms to modulate anti-tumor immunity

Cancer immunotherapy approaches that utilize or enhance patients' inherent immunity have received extensive attention in the past decade. Biomaterial-based nanocarriers with tunable physicochemical properties offer significant promise in cancer immunotherapies. They can lower payload toxicity, provide sustained release of diverse payloads, and target specific disease site(s). Furthermore, nanocarrier-mediated immunotherapies can induce antigen-specific T lymphocytes, tissue-directed immune activation, and apoptosis of cancer cells all of which may comprise a new paradigm in cancer immunotherapy. This review describes key steps in biomaterial-mediated immune activation ranging from biomaterial surface protein adsorption, antigen presenting cell processing, and T cell activation. Nanocarrier-based immunomodulatory mechanisms including inherent adjuvanticity, enhanced cellular internalization, lymph node delivery, cross-presentation, and immunogenic cell death are discussed. In addition, studies that synergistically influence outcomes of nanocarrier-based combination immunotherapies are presented.

Paclitaxel/sunitinib-loaded micelles promote an antitumor response in vitro through synergistic immunogenic cell death for triple-negative breast cancer

Chemotherapy-induced immunogenic cell death (ICD) may offer a strategy to improve the effect of the therapeutic treatment of triple-negative breast cancer (TNBC) by eliciting broad antitumor immunity. However, chemotherapy shows a limited therapeutic effect because of multi-drug resistance and the immunosuppressive tumor microenvironment (TME) of TNBC. The unique pharmacological actions of sunitinib (SUN) indicate its possible synergies with paclitaxel (PTX) to enhance chemo-immunotherapy for TNBC. Here, we prepared a co-delivery platform composed of poly(styrene-co-maleic anhydride) (SMA) via a self-assembly process for a combination of PTX and SUN, which was able to induce a higher synergistic ICD. The nanomicellar delivery of PTX and SUN loaded at an optimal ratio of 1:5 (PTX:SUN) presented the characteristics of an appropriate particle size, long-term stability, and time sequence release which synergistically promoted the apoptosis of MDA-MB-231 tumor cells. Moreover, we demonstrated that the combination of PTX and SUN could significantly induce a synergistic effect because it promoted an ICD response, improved tumor immunogenicity, and regulated immunosuppressive factors in the TME. Overall, PTX and SUN with synergistic effects entrapped in a self-assembly nano-delivery system could offer the potential for clinical applicationof a combination chemo-immunotherapy strategy to improve the effect of the therapeutic treatment of TNBC.