Sugar-Nanocapsules Imprinted with Microbial Molecular Patterns for mRNA Vaccination

Photosynthetic Bacteria-Hitchhiking 2D iMXene-mRNA Vaccine to Enable Photo-Immunogene Cancer Therapy

Therapeutic mRNA vaccines have become powerful therapeutic tools for severe diseases, including infectious diseases and malignant neoplasms. mRNA vaccines encoding tumor-associated antigens provide unprecedented hope for many immunotherapies that have hit the bottleneck. However, the application of mRNA vaccines is limited because of biological instability, innate immunogenicity, and ineffective delivery in vivo. This study aims to construct a novel mRNA vaccine delivery nanosystem to successfully co-deliver a tumor-associated antigen (TAA) encoded by the Wilms' tumor 1 (WT1) mRNA. In this system, named PSB@Nb1.33C/mRNA, photosynthetic bacteria (PSB) efficiently delivers the iMXene-WT1 mRNA to the core tumor region using photo-driven and hypoxia-driven properties. The excellent photothermal therapeutic (PTT) properties of PSB and 2D iMxene (Nb1.33C) trigger tumor immunogenic cell death, which boosts the release of the WT1 mRNA. The released WT1 mRNA is translated, presenting the TAA and amplifying immune effect in vivo. The designed therapeutic strategy demonstrates an excellent ability to inhibit distant tumors and counteract postsurgical lung metastasis. Thus, this study provides an innovative and effective paradigm for tumor immunotherapy, i.e., photo-immunogene cancer therapy, and establishes an efficient delivery platform for mRNA vaccines, thereby opening a new path for the wide application of mRNA vaccines.

Exploring nanocarriers as innovative materials for advanced drug delivery strategies in onco-immunotherapies

In recent years, Onco-immunotherapies (OIMTs) have been shown to be a potential therapy option for cancer. Several immunotherapies have received regulatory approval, while many others are now undergoing clinical testing or are in the early stages of development. Despite this progress, a large number of challenges to the broad use of immunotherapies to treat cancer persists. To make immunotherapy more useful as a treatment while reducing its potentially harmful side effects, we need to know more about how to improve response rates to different types of immunotherapies. Nanocarriers (NCs) have the potential to harness immunotherapies efficiently, enhance the efficiency of these treatments, and reduce the severe adverse reactions that are associated with them. This article discusses the necessity to incorporate nanomedicines in OIMTs and the challenges we confront with current anti-OIMT approaches. In addition, it examines the most important considerations for building nanomedicines for OIMT, which may improve upon current immunotherapy methods. Finally, it highlights the applications and future scenarios of using nanotechnology.

From structural design to delivery: mRNA therapeutics for cancer immunotherapy

mRNA therapeutics have emerged as powerful tools for cancer immunotherapy in accordance with their superiority in expressing all sequence-known proteins in vivo. In particular, with a small dosage of delivered mRNA, antigen-presenting cells (APCs) can synthesize mutant neo-antigens and multi-antigens and present epitopes to T lymphocytes to elicit antitumor effects. In addition, expressing receptors like chimeric antigen receptor (CAR), T-cell receptor (TCR), CD134, and immune-modulating factors including cytokines, interferons, and antibodies in specific cells can enhance immunological response against tumors. With the maturation of in vitro transcription (IVT) technology, large-scale and pure mRNA encoding specific proteins can be synthesized quickly. However, the clinical translation of mRNA-based anticancer strategies is restricted by delivering mRNA into target organs or cells and the inadequate endosomal escape efficiency of mRNA. Recently, there have been some advances in mRNA-based cancer immunotherapy, which can be roughly classified as modifications of the mRNA structure and the development of delivery systems, especially the lipid nanoparticle platforms. In this review, the latest strategies for overcoming the limitations of mRNA-based cancer immunotherapies and the recent advances in delivering mRNA into specific organs and cells are summarized. Challenges and opportunities for clinical applications of mRNA-based cancer immunotherapy are also discussed.

Functional Nucleic Acid-Based Immunomodulation for T Cell-Mediated Cancer Therapy

T cell-mediated immunity plays a pivotal role in cancer immunotherapy. The anticancer actions of T cells are coordinated by a sequence of biological processes, including the capture and presentation of antigens by antigen-presenting cells (APCs), the activation of T cells by APCs, and the subsequent killing of cancer cells by activated T cells. However, cancer cells have various means to evade immune responses. Meanwhile, these vulnerabilities provide potential targets for cancer treatments. Functional nucleic acids (FNAs) make up a class of synthetic nucleic acids with specific biological functions. With their diverse functionality, good biocompatibility, and high programmability, FNAs have attracted widespread interest in cancer immunotherapy. This Review focuses on recent research progress in employing FNAs as molecular tools for T cell-mediated cancer immunotherapy, including corresponding challenges and prospects.

mRNA vaccine designs for optimal adjuvanticity and delivery

Adjuvanticity and delivery are crucial facets of mRNA vaccine design. In modern mRNA vaccines, adjuvant functions are integrated into mRNA vaccine nanoparticles, allowing the co-delivery of antigen mRNA and adjuvants in a unified, all-in-one formulation. In this formulation, many mRNA vaccines utilize the immunostimulating properties of mRNA and vaccine carrier components, including lipids and polymers, as adjuvants. However, careful design is necessary, as excessive adjuvanticity and activation of improper innate immune signalling can conversely hinder vaccination efficacy and trigger adverse effects. mRNA vaccines also require delivery systems to achieve antigen expression in antigen-presenting cells (APCs) within lymphoid organs. Some vaccines directly target APCs in the lymphoid organs, while others rely on APCs migration to the draining lymph nodes after taking up mRNA vaccines. This review explores the current mechanistic understanding of these processes and the ongoing efforts to improve vaccine safety and efficacy based on this understanding.

Advanced nano-based strategies for mRNA tumor vaccine

Tumor vaccine is a promising strategy for cancer immunotherapy by introducing tumor antigens into the body to activate specific anti-tumor immune responses. Along with the technological breakthroughs in genetic engineering and delivery systems, messenger ribonucleic acid (mRNA) technology has achieved unprecedented development and application over the last few years, especially the emergency use authorizations of two mRNA vaccines during the COVID-19 pandemic, which has saved countless lives and makes the world witness the powerful efficacy of mRNA technology in vaccines. However, unlike infectious disease vaccines, which mainly induce humoral immunity, tumor vaccines also need to activate potent cellular immunity to control tumor growth, which creates a higher demand for mRNA delivery to the lymphatic organs and antigen-presenting cells (APCs). Here we review the existing bottlenecks of mRNA tumor vaccines and advanced nano-based strategies to overcome those challenges, as well as future considerations of mRNA tumor vaccines and their delivery systems.

Path towards mRNA delivery for cancer immunotherapy from bench to bedside

Messenger RNA (mRNA) has emerged as a promising therapeutic agent for the prevention and treatment of various diseases. mRNA vaccines, in particular, offer an alternative approach to conventional vaccines, boasting high potency, rapid development capabilities, cost-effectiveness, and safe administration. However, the clinical application of mRNA vaccines is hindered by the challenges of mRNA instability and inefficient in vivo delivery. In recent times, remarkable technological advancements have emerged to address these challenges, utilizing two main approaches: ex vivo transfection of dendritic cells (DCs) with mRNA and direct injection of mRNA-based therapeutics, either with or without a carrier. This review offers a comprehensive overview of major non-viral vectors employed for mRNA vaccine delivery. It showcases notable preclinical and clinical studies in the field of cancer immunotherapy and discusses important considerations for advancing these promising vaccine platforms for broader therapeutic applications. Additionally, we provide insights into future possibilities and the remaining challenges in mRNA delivery technology, emphasizing the significance of ongoing research in mRNA-based therapeutics.

Advances, opportunities and challenges in developing therapeutic cancer vaccines

Therapeutic cancer vaccines have shown promising efficacy in helping immunotherapy for cancer patients, but the systematic characterization of the clinical application and the method for improving efficacy is lacking. Here, we mainly summarize the classification of therapeutic cancer vaccines, including protein vaccines, nucleic acid vaccines, cellular vaccines and anti-idiotypic antibody vaccines, and subdivide the above vaccines according to different types and delivery forms. Additionally, we outline the clinical efficacy and safety of vaccines, as well as the combination strategies of therapeutic cancer vaccines with other therapies. This review will provide a detailed overview and rationale for the future clinical application and development of therapeutic cancer vaccines.

Modulation of immune cells with mRNA nanoformulations for cancer immunotherapy

The global adaptation of mRNA vaccines to protect against the COVID-19 pandemic was a major interdisciplinary milestone, demonstrating the potential of combining mRNA applications with nanotechnology. This innovative strategy holds great promise as an improved therapeutic modality for cancer immunotherapy, as further development could facilitate targeted mRNA delivery to specific immune cells and enable manipulation of effector functions. Toward this, researchers have made substantial efforts to modulate various immune cell types, including lymphoid organ dendritic cells for cancer vaccines, peripheral blood lymphocytes for in situ T-cell therapy, and macrophages in the tumor microenvironment to restore antitumor functions. Here, we highlight recent advances in mRNA nanoformulations for cancer immunotherapy, emphasizing strategies for target cell engagement in different immunological sites.

The Distinct Properties of Polysaccharide Nanoparticles Tune Immune Responses against mRNA Antigen via Stimulator of Interferon Genes-Mediated Autophagy and Inflammasome

mRNA antigens require powerful nanocarriers for efficient delivery, as well as immunomodulators for controlling their excessive immunogenicity. While lipid nanoparticles (LNPs) used in mRNA vaccines exhibited systemic toxicity, there is an urgent need for developing potential nanoparticles with strong immunoenhancing effects for mRNA antigens. Although natural polysaccharides as adjuvants assisted various types of antigens in triggering potent immune responses, they have been rarely investigated in mRNA vaccines. Here, we constructed four polysaccharide nanoparticles with different molecular weights (MWs) to deliver and protect mRNA antigens, and boosted antigen cross-presentation, DC maturation, CD4+/CD8+T cell responses and humoral immune responses. Importantly, the immunoenhancing capacities of polysaccharide nanoparticles were highly dependent on their MW properties. CS NPs with high MW initiated stimulator of interferon genes (STING)-mediated autophagy and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome signaling, consequently possessing superior mRNA antigen-specific immune responses in vitro and in vivo. In contrast, CS NPs with low MWs induced NLRP3 signaling without STING or autophagy activation, which failed to induce robust immune responses. Therefore, it uncovered the MW-dependent immunoenhancing effects and mechanism of polysaccharide nanoparticles, providing a platform for designing potential nanosized polysaccharide immunomodulators for mRNA vaccines.

mRNA Cancer Vaccines: Construction and Boosting Strategies

In late 2020, the U.S. Food and Drug Administration (FDA) approved a lipid-based mRNA vaccine for the prevention of COVID-19, which has pushed this field to be more closely studied and motivated researchers to delve deeper into mRNA therapeutics. To date, the research on mRNA cancer vaccines has been developed rapidly, and substantial hopeful therapeutic results have been achieved against various solid tumors in clinical trials. In this review, we first introduce three main components of mRNA cancer vaccines, including mRNA antigens, adjuvants, and delivery vectors. Engineering these components can optimize the therapeutic effects of mRNA cancer vaccines. For instance, appropriate modification of mRNA structure can alleviate the poor stability and innate immunogenicity of mRNA, and the use of mRNA delivery vectors can address the issues of low delivery efficiency in vivo. Second, we emphatically discuss some strategies to further improve the efficacy of mRNA cancer vaccines, namely modulating the immunosuppressive tumor environment, optimizing administration routes, achieving targeting delivery to intended tissues or organs, and employing combination therapy. These strategies can strengthen the tumor inhibitory ability of mRNA cancer vaccines and increase the possibility of tumor elimination. Finally, we point out some challenges in the clinical practice of mRNA cancer vaccines and offer our perspectives on future developments in this rapidly evolving field. It is anticipated that mRNA cancer vaccines will be rapidly developed for clinical cancer therapy in the near future.

mRNA-based vaccines and therapeutics: an in-depth survey of current and upcoming clinical applications

mRNA-based drugs have tremendous potential as clinical treatments, however, a major challenge in realizing this drug class will promise to develop methods for safely delivering the bioactive agents with high efficiency and without activating the immune system. With regard to mRNA vaccines, researchers have modified the mRNA structure to enhance its stability and promote systemic tolerance of antigenic presentation in non-inflammatory contexts. Still, delivery of naked modified mRNAs is inefficient and results in low levels of antigen protein production. As such, lipid nanoparticles have been utilized to improve delivery and protect the mRNA cargo from extracellular degradation. This advance was a major milestone in the development of mRNA vaccines and dispelled skepticism about the potential of this technology to yield clinically approved medicines. Following the resounding success of mRNA vaccines for COVID-19, many other mRNA-based drugs have been proposed for the treatment of a variety of diseases. This review begins with a discussion of mRNA modifications and delivery vehicles, as well as the factors that influence administration routes. Then, we summarize the potential applications of mRNA-based drugs and discuss further key points pertaining to preclinical and clinical development of mRNA drugs targeting a wide range of diseases. Finally, we discuss the latest market trends and future applications of mRNA-based drugs.

Enhanced Local Delivery of Engineered IL-2 mRNA by Porous Silica Nanoparticles to Promote Effective Antitumor Immunity

Localized expression of immunomodulatory molecules can stimulate immune responses against tumors in the tumor microenvironment while avoiding toxicities associated with systemic administration. In this study, we developed a polyethylenimine-modified porous silica nanoparticle (PPSN)-based delivery platform carrying cytokine mRNA for local immunotherapy in vivo. Our delivery platform was significantly more efficient than FDA-approved lipid nanoparticles for localized mRNA translation. We observed no off-target translation of mRNA in any organs and no evidence of systemic toxicity. Intratumoral injection of cytokine mRNA-loaded PPSNs led to high-level expression of protein within the tumor and stimulated immunogenic cancer cell death. Additionally, combining cytokine mRNA with an immune checkpoint inhibitor enhanced anticancer responses in several murine cancer models and enabled the inhibition of distant metastatic tumors. Our results demonstrate the potential of PPSNs-mediated mRNA delivery as a specific, effective, and safe platform for mRNA-based therapeutics in cancer immunotherapy.

Engineering nanoparticle toolkits for mRNA delivery

The concept of using mRNA to produce its own medicine in situ in the body makes it an ideal drug candidate, holding great potential to revolutionize the way we approach medicine. The unique characteristics of mRNA, as well as its customizable biomedical functions, call for the rational design of delivery systems to protect and transport mRNA molecules. In this review, a nanoparticle toolkit is presented for the development of mRNA-based therapeutics from a drug delivery perspective. Nano-delivery systems derived from either natural systems or chemical synthesis, in the nature of organic or inorganic materials, are summarised. Delivery strategies in controlling the tissue targeting and mRNA release, as well as the role of nanoparticles in building and boosting the activity of mRNA drugs, have also been introduced. In the end, our insights into the clinical and translational development of mRNA nano-drugs are presented.

Advances in mRNA therapeutics for cancer immunotherapy: From modification to delivery

RNA vaccines have demonstrated their ability to solve the issues posed by the COVID-19 pandemic. This success has led to the renaissance of research into mRNA and their nanoformulations as potential therapeutic modalities for various diseases. The potential of mRNA as a template for synthesizing proteins and protein fragments for cancer immunotherapy is now being explored. Despite the promise, the use of mRNA in cancer immunotherapy is limited by challenges, such as low stability against extracellular RNases, poor delivery efficiency to the target organs and cells, short circulatory half-life, variable expression levels and duration. This review highlights recent advances in chemical modification and advanced delivery systems that are helping to address these challenges and unlock the biological and pharmacological potential of mRNA therapeutics in cancer immunotherapy. The review concludes by discussing future perspectives for mRNA-based cancer immunotherapy, which holds great promise as a next-generation therapeutic modality.

The use of RNA-based treatments in the field of cancer immunotherapy

Over the past several decades, mRNA vaccines have evolved from a theoretical concept to a clinical reality. These vaccines offer several advantages over traditional vaccine techniques, including their high potency, rapid development, low-cost manufacturing, and safe administration. However, until recently, concerns over the instability and inefficient distribution of mRNA in vivo have limited their utility. Fortunately, recent technological advancements have mostly resolved these concerns, resulting in the development of numerous mRNA vaccination platforms for infectious diseases and various types of cancer. These platforms have shown promising outcomes in both animal models and humans. This study highlights the potential of mRNA vaccines as a promising alternative approach to conventional vaccine techniques and cancer treatment. This review article aims to provide a thorough and detailed examination of mRNA vaccines, including their mechanisms of action and potential applications in cancer immunotherapy. Additionally, the article will analyze the current state of mRNA vaccine technology and highlight future directions for the development and implementation of this promising vaccine platform as a mainstream therapeutic option. The review will also discuss potential challenges and limitations of mRNA vaccines, such as their stability and in vivo distribution, and suggest ways to overcome these issues. By providing a comprehensive overview and critical analysis of mRNA vaccines, this review aims to contribute to the advancement of this innovative approach to cancer treatment.

Nanocarriers for cancer nano-immunotherapy

The host immune system possesses an intrinsic ability to target and kill cancer cells in a specific and adaptable manner that can be further enhanced by cancer immunotherapy, which aims to train the immune system to boost the antitumor immune response. Several different categories of cancer immunotherapy have emerged as new standard cancer therapies in the clinic, including cancer vaccines, immune checkpoint inhibitors, adoptive T cell therapy, and oncolytic virus therapy. Despite the remarkable survival benefit for a subset of patients, the low response rate and immunotoxicity remain the major challenges for current cancer immunotherapy. Over the last few decades, nanomedicine has been intensively investigated with great enthusiasm, leading to marked advancements in nanoparticle platforms and nanoengineering technology. Advances in nanomedicine and immunotherapy have also led to the emergence of a nascent research field of nano-immunotherapy, which aims to realize the full therapeutic potential of immunotherapy with the aid of nanomedicine. In particular, nanocarriers present an exciting opportunity in immuno-oncology to boost the activity, increase specificity, decrease toxicity, and sustain the antitumor efficacy of immunological agents by potentiating immunostimulatory activity and favorably modulating pharmacological properties. This review discusses the potential of nanocarriers for cancer immunotherapy and introduces preclinical studies designed to improve clinical cancer immunotherapy modalities using nanocarrier-based engineering approaches. It also discusses the potential of nanocarriers to address the challenges currently faced by immuno-oncology as well as the challenges for their translation to clinical applications.

Emerging Progress of RNA-Based Antitumor Therapeutics

RNA-based therapeutics (e.g., mRNAs, siRNAs, microRNAs, ASOs, and saRNAs) have considerable potential for tumor treatment. The development and optimization of RNA modifications and delivery systems enable the stable and efficient delivery of RNA cargos in vivo to elicit an antitumor response. Targeted RNA-based therapeutics with multiple specificities and high efficacies are now available. In this review, we discuss progress in RNA-based antitumor therapeutics, including mRNAs, siRNAs, miRNAs, ASOs, saRNAs, RNA aptamers, and CRISPR-based gene editing. We focus on the immunogenicity, stability, translation efficiency, and delivery of RNA drugs, and summarize their optimization and the development of delivery systems. In addition, we describe the mechanisms by which RNA-based therapeutics induce antitumor responses. Furthermore, we review the merits and limitations of RNA cargos and their therapeutic potential for cancers.

Polysaccharide-Based Stimulus-Responsive Nanomedicines for Combination Cancer Immunotherapy

Cancer immunotherapy is a promising antitumor approach, whereas nontherapeutic side effects, tumor microenvironment (TME) intricacy, and low tumor immunogenicity limit its therapeutic efficacy. In recent years, combination immunotherapy with other therapies has been proven to considerably increase antitumor efficacy. However, achieving codelivery of the drugs to the tumor site remains a major challenge. Stimulus-responsive nanodelivery systems show controlled drug delivery and precise drug release. Polysaccharides, a family of potential biomaterials, are widely used in the development of stimulus-responsive nanomedicines due to their unique physicochemical properties, biocompatibility, and modifiability. Here, the antitumor activity of polysaccharides and several combined immunotherapy strategies (e.g., immunotherapy combined with chemotherapy, photodynamic therapy, or photothermal therapy) are summarized. More importantly, the recent progress of polysaccharide-based stimulus-responsive nanomedicines for combination cancer immunotherapy is discussed, with the focus on construction of nanomedicine, targeted delivery, drug release, and enhanced antitumor effects. Finally, the limitations and application prospects of this new field are discussed.

Nanoformulations targeting immune cells for cancer therapy: mRNA therapeutics

The approved worldwide use of two messenger RNA (mRNA) vaccines (BNT162b2 and mRNA-1273) in late 2020 has proven the remarkable success of mRNA therapeutics together with lipid nanoformulation technology in protecting people against coronaviruses during COVID-19 pandemic. This unprecedented and exciting dual strategy with nanoformulations and mRNA therapeutics in play is believed to be a promising paradigm in targeted cancer immunotherapy in future. Recent advances in nanoformulation technologies play a prominent role in adapting mRNA platform in cancer treatment. In this review, we introduce the biologic principles and advancements of mRNA technology, and chemistry fundamentals of intriguing mRNA delivery nanoformulations. We discuss the latest promising nano-mRNA therapeutics for enhanced cancer immunotherapy by modulation of targeted specific subtypes of immune cells, such as dendritic cells (DCs) at peripheral lymphoid organs for initiating mRNA cancer vaccine-mediated antigen specific immunotherapy, and DCs, natural killer (NK) cells, cytotoxic T cells, or multiple immunosuppressive immune cells at tumor microenvironment (TME) for reversing immune evasion. We highlight the clinical progress of advanced nano-mRNA therapeutics in targeted cancer therapy and provide our perspectives on future directions of this transformative integrated technology toward clinical implementation.

Nanomaterials-Based Novel Immune Strategies in Clinical Translation for Cancer Therapy

Immunotherapy shows a lot of promise for addressing the problems with traditional cancer treatments. Researchers and clinicians are working to create innovative immunological techniques for cancer detection and treatment that are more selective and have lower toxicity. An emerging field in cancer therapy, immunomodulation offers patients an alternate approach to treating cancer. These therapies use the host's natural defensive systems to identify and remove malignant cells in a targeted manner. Cancer treatment is now undergoing somewhat of a revolution due to recent developments in nanotechnology. Diverse nanomaterials (NMs) have been employed to overcome the limits of conventional anti-cancer treatments such as cytotoxic, surgery, radiation, and chemotherapy. Aside from that, NMs could interact with live cells and influence immune responses. In contrast, unexpected adverse effects such as necrosis, hypersensitivity, and inflammation might result from the immune system (IS)'s interaction with NMs. Therefore, to ensure the efficacy of immunomodulatory nanomaterials, it is essential to have a comprehensive understanding of the intricate interplay that exists between the IS and NMs. This review intends to present an overview of the current achievements, challenges, and improvements in using immunomodulatory nanomaterials (iNMs) for cancer therapy, with an emphasis on elucidating the mechanisms involved in the interaction between NMs and the immune system of the host.

mRNA-From COVID-19 Treatment to Cancer Immunotherapy

This review provides an overview covering mRNA from its use in the COVID-19 pandemic to cancer immunotherapy, starting from the selection of appropriate antigens, tumor-associated and tumor-specific antigens, neoantigens, the basics of optimizing the mRNA molecule in terms of stability, efficacy, and tolerability, choosing the best formulation and the optimal route of administration, to summarizing current clinical trials of mRNA vaccines in tumor therapy.

Induction of T-helper-17-cell-mediated anti-tumour immunity by pathogen-mimicking polymer nanoparticles

The effectivity of cancer immunotherapies is hindered by immunosuppressive tumour microenvironments that are poorly infiltrated by effector T cells and natural killer cells. In infection and autoimmune disease, the recruitment and activation of effector immune cells is coordinated by pro-inflammatory T helper 17 (TH17) cells. Here we show that pathogen-mimicking hollow nanoparticles displaying mannan (a polysaccharide that activates TH17 cells in microbial cell walls) limit the fraction of regulatory T cells and induce TH17-cell-mediated anti-tumour responses. The nanoparticles activate the pattern-recognition receptor Dectin-2 and Toll-like receptor 4 in dendritic cells, and promote the differentiation of CD4+ T cells into the TH17 phenotype. In mice, intra-tumoural administration of the nanoparticles decreased the fraction of regulatory T cells in the tumour while markedly increasing the fractions of TH17 cells (and the levels of TH17-cell-associated cytokines), CD8+ T cells, natural killer cells and M1-like macrophages. The anti-tumoural activity of the effector cells was amplified by an agonistic antibody against the co-stimulatory receptor OX40 in multiple mouse models. Nanomaterials that induce TH17-cell-mediated immune responses may have therapeutic potential.

mRNA-Based Vaccines and Therapeutics for COVID-19 and Future Pandemics

An unheard mobilization of resources to find SARS-CoV-2 vaccines and therapies has been sparked by the COVID-19 pandemic. Two years ago, COVID-19's launch propelled mRNA-based technologies into the public eye. Knowledge gained from mRNA technology used to combat COVID-19 is assisting in the creation of treatments and vaccines to treat existing illnesses and may avert pandemics in the future. Exploiting the capacity of mRNA to create therapeutic proteins to impede or treat a variety of illnesses, including cancer, is the main goal of the quickly developing, highly multidisciplinary field of biomedicine. In this review, we explore the potential of mRNA as a vaccine and therapeutic using current research findings.

Locoregional Lymphatic Delivery Systems Using Nanoparticles and Hydrogels for Anticancer Immunotherapy

The lymphatic system has gained significant interest as a target tissue to control cancer progress, which highlights its central role in adaptive immune response. Numerous mechanistic studies have revealed the benefits of nano-sized materials in the transport of various cargos to lymph nodes, overcoming barriers associated with lymphatic physiology. The potential of sustained drug delivery systems in improving the therapeutic index of various immune modulating agents is also being actively discussed. Herein, we aim to discuss design rationales and principles of locoregional lymphatic drug delivery systems for invigorating adaptive immune response for efficient antitumor immunotherapy and provide examples of various advanced nanoparticle- and hydrogel-based formulations.

Tumor microenvironment and immunotherapy of oral cancer

Oral cancer is one of the most common malignant tumors of the head and neck, not only affects the appearance, but also affects eating and even endangers life. The clinical treatments of oral cancer mainly include surgery, radiotherapy, and chemotherapy. However, unsatisfactory therapeutic effect and toxic side effects are still the main problems in clinical treatment. Tumor microenvironment (TME) is not only closely related to the occurrence, growth, and metastasis of tumor but also works in the diagnosis, prevention, and treatment of tumor and prognosis. Future studies should continue to investigate the relationship of TME and oral cancer therapy. This purpose of this review was to analyze the characteristics of oral cancer microenvironment, summarize the traditional oral cancer therapy and immunotherapy strategies, and finally prospect the development prospects of oral cancer immunotherapy. Immunotherapy targeting tumor microenvironment is expected to provide a new strategy for clinical treatment of oral cancer.

Lipid nanoparticle-based mRNA vaccines in cancers: Current advances and future prospects

Messenger RNA (mRNA) vaccines constitute an emerging therapeutic method with the advantages of high safety and efficiency as well as easy synthesis; thus, they have been widely used in various human diseases, especially in malignant cancers. However, the mRNA vaccine technology has some limitations, such as instability and low transitive efficiency in vivo, which greatly restrict its application. The development of nanotechnology in the biomedical field offers new strategies and prospects for the early diagnosis and treatment of human cancers. Recent studies have demonstrated that Lipid nanoparticle (LNP)-based mRNA vaccines can address the poor preservation and targeted inaccuracy of mRNA vaccines. As an emerging cancer therapy, mRNA vaccines potentially have broad future applications. Unlike other treatments, cancer mRNA vaccines provide specific, safe, and tolerable treatments. Preclinical studies have used personalized vaccines to demonstrate the anti-tumor effect of mRNA vaccines in the treatment of various solid tumors, including colorectal and lung cancer, using these in a new era of therapeutic cancer vaccines. In this review, we have summarized the latest applications and progress of LNP-based mRNA vaccines in cancers, and discussed the prospects and limitations of these fields, thereby providing novel strategies for the targeted therapy of cancers.

In vivo fate and intracellular trafficking of vaccine delivery systems

With the pandemic of severe acute respiratory syndrome coronavirus 2, vaccine delivery systems emerged as a core technology for global public health. Given that antigen processing takes place inside the cell, the intracellular delivery and trafficking of a vaccine antigen will contribute to vaccine efficiency. Investigations focusing on the in vivo behavior and intracellular transport of vaccines have improved our understanding of the mechanisms relevant to vaccine delivery systems and facilitated the design of novel potent vaccine platforms. In this review, we cover the intracellular trafficking and in vivo fate of vaccines administered via various routes and delivery systems. To improve immune responses, researchers have used various strategies to modulate vaccine platforms and intracellular trafficking. In addition to progress in vaccine trafficking studies, the challenges and future perspectives for designing next-generation vaccines are discussed.

Nano Drug Delivery System for Tumor Immunotherapy: Next-Generation Therapeutics

Tumor immunotherapy is an artificial stimulation of the immune system to enhance anti-cancer response. It has become a powerful clinical strategy for treating cancer. The number of immunotherapy drug approvals has been increasing in recent years, and many treatments are in clinical and preclinical stages. Despite this progress, the special tumor heterogeneity and immunosuppressive microenvironment of solid tumors made immunotherapy in the majority of cancer cases difficult. Therefore, understanding how to improve the intratumoral enrichment degree and the response rate of various immunotherapy drugs is key to improve efficacy and control adverse reactions. With the development of materials science and nanotechnology, advanced biomaterials such as nanoparticle and drug delivery systems like T-cell delivery therapy can improve effectiveness of immunotherapy while reducing the toxic side effects on non-target cells, which offers innovative ideas for improving immunity therapeutic effectiveness. In this review, we discuss the mechanism of tumor cell immune escape and focus on current immunotherapy (such as cytokine immunotherapy, therapeutic monoclonal antibody immunotherapy, PD-1/PD-L1 therapy, CAR-T therapy, tumor vaccine, oncolytic virus, and other new types of immunity) and its challenges as well as the latest nanotechnology (such as bionic nanoparticles, self-assembled nanoparticles, deformable nanoparticles, photothermal effect nanoparticles, stimuli-responsive nanoparticles, and other types) applications in cancer immunotherapy.

Nucleic acid and oligonucleotide delivery for activating innate immunity in cancer immunotherapy

A group of nucleic acids and oligonucleotides play various roles in the innate immune system. They can stimulate pattern recognition receptors to activate innate immune cells, encode immunostimulatory proteins or peptides, or silence specific genes to block negative regulators of immune cells. Given the limitations of current cancer immunotherapy, there has been increasing interest in harnessing innate immune responses by nucleic acids and oligonucleotides. The poor biopharmaceutical properties of nucleic acids and oligonucleotides make it critical to use carriers that can protect them in circulation, retain them in the tumor microenvironment, and bring them to intracellular targets. Therefore, various gene carriers have been repurposed to deliver nucleic acids and oligonucleotides for cancer immunotherapy and improve their safety and activity. Here, we review recent studies that employed carriers to enhance the functions of nucleic acids and oligonucleotides and overall immune responses to cancer, and discuss remaining challenges and future opportunities in the development of nucleic acid-based immunotherapeutics.

mRNA cancer vaccines: Advances, trends and challenges

Patients exhibit good tolerance to messenger ribonucleic acid (mRNA) vaccines, and the choice of encoded molecules is flexible and diverse. These vaccines can be engineered to express full-length antigens containing multiple epitopes without major histocompatibility complex (MHC) restriction, are relatively easy to control and can be rapidly mass produced. In 2021, the U.S. Food and Drug Administration (FDA) approved the first mRNA-based coronavirus disease 2019 (COVID-19) vaccine produced by Pfizer and BioNTech, which has generated enthusiasm for mRNA vaccine research and development. Based on the above characteristics and the development of mRNA vaccines, mRNA cancer vaccines have become a research hotspot and have undergone rapid development, especially in the last five years. This review analyzes the advances in mRNA cancer vaccines from various perspectives, including the selection and expression of antigens/targets, the application of vectors and adjuvants, different administration routes, and preclinical evaluation, to reflect the trends and challenges associated with these vaccines.

Yeast-derived nanoparticles remodel the immunosuppressive microenvironment in tumor and tumor-draining lymph nodes to suppress tumor growth

Microbe-based cancer immunotherapy has recently emerged as a hot topic for cancer treatment. However, serious limitations remain including infection associated side-effect and unsatisfactory outcomes in clinic trials. Here, we fabricate different sizes of nano-formulations derived from yeast cell wall (YCW NPs) by differential centrifugation. The induction of anticancer immunity of our formulations appears to inversely correlate with their size due to the ability to accumulate in tumor-draining lymph node (TDLN). Moreover, we use a percolation model to explain their distribution behavior toward TDLN. The abundance and functional orientation of each effector component are significantly improved not only in the microenvironment in tumor but also in the TDLN following small size YCW NPs treatment. In combination with programmed death-ligand 1 (PD-L1) blockade, we demonstrate anticancer efficiency in melanoma-challenged mice. We delineate potential strategy to target immunosuppressive microenvironment by microbe-based nanoparticles and highlight the role of size effect in microbe-based immune therapeutics.

Components of the yeast cell wall, including but not limited to β-glucan, have been reported to act as danger signals and promote immune responses. Here the authors report the design and anti-tumor immune responses elicited by yeast cell wall-based nanoparticles in preclinical cancer models.

Polymeric particle-based therapies for acute inflammatory diseases

Acute inflammation is essential for initiating and coordinating the body's response to injuries and infections. However, in acute inflammatory diseases, inflammation is not resolved but propagates further, which can ultimately lead to tissue damage such as in sepsis, acute respiratory distress syndrome and deep vein thrombosis. Currently, clinical protocols are limited to systemic steroidal treatments, fluids and antibiotics that focus on eradicating inflammation rather than modulating it. Strategies based on stem cell therapeutics and selective blocking of inflammatory molecules, despite showing great promise, still lack the scalability and specificity required to treat acute inflammation. By contrast, polymeric particle systems benefit from uniform manufacturing at large scales while preserving biocompatibility and versatility, thus providing an ideal platform for immune modulation. Here, we outline design aspects of polymeric particles including material, size, shape, deformability and surface modifications, providing a strategy for optimizing the targeting of acute inflammation.

Formulation and Delivery Technologies for mRNA Vaccines

mRNA vaccines have become a versatile technology for the prevention of infectious diseases and the treatment of cancers. In the vaccination process, mRNA formulation and delivery strategies facilitate effective expression and presentation of antigens, and immune stimulation. mRNA vaccines have been delivered in various formats: encapsulation by delivery carriers, such as lipid nanoparticles, polymers, peptides, free mRNA in solution, and ex vivo through dendritic cells. Appropriate delivery materials and formulation methods often boost the vaccine efficacy which is also influenced by the selection of a proper administration route. Co-delivery of multiple mRNAs enables synergistic effects and further enhances immunity in some cases. In this chapter, we overview the recent progress and existing challenges in the formulation and delivery technologies of mRNA vaccines with perspectives for future development.

Tailoring the physicochemical properties of nanomaterials for immunomodulation

Immunomodulation is poised to revolutionize the treatment of cancer, autoimmune diseases, and many other inflammation-related disorders. The immune system in these conditions can be either activated or suppressed by nanocarriers loaded with bioactive molecules. Although immunomodulation via these therapeutics has long been recognized, and a broad range of nanocarriers have been designed to accommodate varied usages, less studies have focused on the effects of nanomaterial physicochemical properties on immune responses, especially the immunity altered by nanocarrier materials alone. Conclusions are sometimes seemly inconsistent due to the complexities of nanomaterials and the immune system. An in-depth understanding of the nanocarrier-induced immune responses is essential for clinical applications. In this review, we summarize recent studies of the immune responses influenced by nanomaterial physicochemical properties with an emphasis on the intrinsic features of nanomaterials that modulate the innate and adaptive immunities. We then provide our perspectives on the design of nanomaterials for immunomodulation.

mRNA - A game changer in regenerative medicine, cell-based therapy and reprogramming strategies

After thirty years of intensive research shaping and optimizing the technology, the approval of the first mRNA-based formulation by the EMA and FDA in order to stop the COVID-19 pandemic was a breakthrough in mRNA research. The astonishing success of these vaccines have brought the mRNA platform into the spotlight of the scientific community. The remarkable persistence of the groundwork is mainly attributed to the exceptional benefits of mRNA application, including the biological origin, immediate but transitory mechanism of action, non-integrative properties, safe and relatively simple manufacturing as well as the flexibility to produce any desired protein. Based on these advantages, a practical implementation of in vitro transcribed mRNA has been considered in most areas of medicine. In this review, we discuss the key preconditions for the rise of the mRNA in the medical field, including the unique structural and functional features of the mRNA molecule and its vehicles, which are crucial aspects for a production of potent mRNA-based therapeutics. Further, we focus on the utility of mRNA tools particularly in the scope of regenerative medicine, i.e. cell reprogramming approaches or manipulation strategies for targeted tissue restoration. Finally, we highlight the strong clinical potential but also the remaining hurdles to overcome for the mRNA-based regenerative therapy, which is only a few steps away from becoming a reality.

Innovations in lymph node targeting nanocarriers

Lymph nodes are secondary lymphoid tissues in the body that facilitate the co-mingling of immune cells to enable and regulate the adaptive immune response. They are also tissues implicated in a variety of diseases, including but not limited to malignancy. The ability to access lymph nodes is thus attractive for a variety of therapeutic and diagnostic applications. As nanotechnologies are now well established for their potential in translational biomedical applications, their high relevance to applications that involve lymph nodes is highlighted. Herein, established paradigms of nanocarrier design to enable delivery to lymph nodes are discussed, considering the unique lymph node tissue structure as well as lymphatic system physiology. The influence of delivery mechanism on how nanocarrier systems distribute to different compartments and cells that reside within lymph nodes is also elaborated. Finally, current advanced nanoparticle technologies that have been developed to enable lymph node delivery are discussed.

Dynamic mRNA polyplexes benefit from bioreducible cleavage sites for in vitro and in vivo transfer

Currently, messenger RNA (mRNA)-based lipid nanoparticle formulations revolutionize the clinical field. Cationic polymer-based complexes (polyplexes) represent an alternative compound class for mRNA delivery. After establishing branched polyethylenimine with a succinylation degree of 10% (succPEI) as highly effective positive mRNA transfection standard, a diverse library of PEI-like peptides termed sequence-defined oligoaminoamides (OAAs) was screened for mRNA delivery. Notably, sequences, which had previously been identified as potent plasmid DNA (pDNA) or small-interfering RNA (siRNA) carriers, displayed only moderate mRNA transfection activity. A second round of screening combined the cationizable building block succinoyl tetraethylene pentamine and histidines for endosomal buffering, tyrosine tripeptides and various fatty acids for mRNA polyplex stabilization, as well as redox-sensitive units for programmed intracellular release. For the tested OAA carriers, balancing of extracellular stability, endosomal lytic activity, and intracellular release capability was found to be of utmost importance for optimum mRNA transfection efficiency. OAAs with T-shape topology containing two oleic acids as well-stabilizing fatty acids, attached via a dynamic bioreducible building block, displayed superior activity with up to 1000-fold increased transfection efficiency compared to their non-reducible analogs. In the absence of the dynamic linkage, incorporation of shorter less stabilizing fatty acids could only partly compensate for mRNA delivery. Highest GFP expression and the largest fraction of transfected cells (96%) could be detected for the bioreducible OAA with incorporated histidines and a dioleoyl motif, outperforming all other tested carriers as well as the positive control succPEI. The good in vitro performance of the dynamic lead structure was verified in vivo upon intratracheal administration of mRNA complexes in mice.

Nucleic acid delivery for therapeutic applications

Recent medical advances have exploited the ability to address a given disease at the underlying level of transcription and translation. These treatment paradigms utilize nucleic acids - including short interfering RNA (siRNA), microRNA (miRNA), antisense oligonucleotides (ASO), and messenger RNA (mRNA) - to achieve a desired outcome ranging from gene knockdown to induced expression of a selected target protein. Towards this end, numerous strategies for encapsulation or stabilization of various nucleic acid structures have been developed in order to achieve intracellular delivery. In this review, we discuss several therapeutic applications of nucleic acids directed towards specific diseases and tissues of interest, in particular highlighting recent technologies which have reached late-stage clinical trials and received FDA approval.

Lipids and Lipid Derivatives for RNA Delivery

RNA-based therapeutics have shown great promise in treating a broad spectrum of diseases through various mechanisms including knockdown of pathological genes, expression of therapeutic proteins, and programmed gene editing. Due to the inherent instability and negative-charges of RNA molecules, RNA-based therapeutics can make the most use of delivery systems to overcome biological barriers and to release the RNA payload into the cytosol. Among different types of delivery systems, lipid-based RNA delivery systems, particularly lipid nanoparticles (LNPs), have been extensively studied due to their unique properties, such as simple chemical synthesis of lipid components, scalable manufacturing processes of LNPs, and wide packaging capability. LNPs represent the most widely used delivery systems for RNA-based therapeutics, as evidenced by the clinical approvals of three LNP-RNA formulations, patisiran, BNT162b2, and mRNA-1273. This review covers recent advances of lipids, lipid derivatives, and lipid-derived macromolecules used in RNA delivery over the past several decades. We focus mainly on their chemical structures, synthetic routes, characterization, formulation methods, and structure-activity relationships. We also briefly describe the current status of representative preclinical studies and clinical trials and highlight future opportunities and challenges.

A simple and general strategy for postsurgical personalized cancer vaccine therapy based on an injectable dynamic covalent hydrogel

Cancer vaccines artificially stimulate the immune system against cancer and are considered the most promising treatment of cancer. However, the current progress in vaccine research against cancer is still limited and slow, partially due to the difficulties in identifying and obtaining tumor-specific antigens. Considering surgery as the first choice for tumor treatment in most cases, the authors evaluated whether the resected tumor can be directly used as a source of tumor antigens for designing personalized cancer vaccines. Based on this idea, herein, the authors report a dynamic covalent hydrogel-based vaccine (DCHVax) for personalized postsurgical management of tumors. The study uses proteins extracted from the resected tumor as antigens, CpG as the adjuvant, and a multi-armed poly(ethylene glycol) (8-arm PEG)/oxidized dextran (ODEX) dynamically cross-linked hydrogel as the matrix. Subcutaneous injection of DCHVax recruits dendritic cells to the matrix in situ and elicits robust tumor-specific immune responses. Thus, it effectively inhibits the postoperative growth of the residual tumor in several murine tumor models. This simple and personalized method to develop cancer vaccines may be promising in developing clinically relevant strategies for postoperative cancer treatment.

Bio-mimic particles for the enhanced vaccinations: Lessons learnt from the natural traits and pathogenic invasion

In the combat against pathogens, the immune systems were evolved with the immune recognitions against the various danger signals, which responded vigorously upon the pathogen invasions and elicited potent antibodies or T cell engagement against the re-infections. Envisage with the prevailing pandemics and increasing demands for cancer vaccines, bio-mimic particles were developed to imitate the natural traits of the pathogens, which conferred the optimal strategies to stimulate the immune engagement and let to the increased vaccine efficacy. Here, the recent development in bio-mimic particles, as well as the natural cues from the pathogens were discussed. As such, the designing principles that adapted from the physiochemical properties of the pathogens were unfolded as the surface characteristics (hydrophobic, nano-pattern, antigen display, charge), properties (size, shape, softness) and the delivered components (peptide, protein, nuclear acids, toll-like receptor (TLR) agonist, antibody). Additionally, the strategies for the efficient delivery, regarding the biodistribution, internalization and presentation of the antigens were also illustrated. Through reviewing the state-of-art in biomimetic particles, the lesson learnt from the natural traits and pathogenic invasion may shed light on the rational design for the enhanced vaccinations.

Harnessing Innate Immunity Using Biomaterials for Cancer Immunotherapy

The discovery of immune checkpoint blockade has revolutionized the field of immuno-oncology and established the foundation for developing various new therapies that can surpass conventional cancer treatments. Most recent immunotherapeutic strategies have focused on adaptive immune responses by targeting T cell-activating pathways, genetic engineering of T cells with chimeric antigen receptors, or bispecific antibodies. Despite the unprecedented clinical success, these T cell-based treatments have only benefited a small proportion of patients. Thus, the need for the next generation of cancer immunotherapy is driven by identifying novel therapeutic molecules or new immunoengineered cells. To maximize the therapeutic potency via innate immunogenicity, the convergence of innate immunity-based therapy and biomaterials is required to yield an efficient index in clinical trials. This review highlights how biomaterials can efficiently reprogram and recruit innate immune cells in tumors and ultimately initiate activation of T cell immunity against advanced cancers. Moreover, the design and specific biomaterials that improve innate immune cells' targeting ability to selectively activate immunogenicity with minimal adverse effects are discussed.

Nanosac, a Noncationic and Soft Polyphenol Nanocapsule, Enables Systemic Delivery of siRNA to Solid Tumors

For systemic delivery of small interfering RNA (siRNA) to solid tumors, the carrier must circulate avoiding premature degradation, extravasate and penetrate tumors, enter target cells, traffic to the intracellular destination, and release siRNA for gene silencing. However, existing siRNA carriers, which typically exhibit positive charges, fall short of these requirements by a large margin; thus, systemic delivery of siRNA to tumors remains a significant challenge. To overcome the limitations of existing approaches, we have developed a carrier of siRNA, called "Nanosac", a noncationic soft polyphenol nanocapsule. A siRNA-loaded Nanosac is produced by sequential coating of mesoporous silica nanoparticles (MSNs) with siRNA and polydopamine, followed by removal of the sacrificial MSN core. The Nanosac recruits serum albumin, co-opts caveolae-mediated endocytosis to enter tumor cells, and efficiently silences target genes. The softness of Nanosac improves extravasation and penetration into tumors compared to its hard counterpart. As a carrier of siRNA targeting PD-L1, Nanosac induces a significant attenuation of CT26 tumor growth by immune checkpoint blockade. These results support the utility of Nanosac in the systemic delivery of siRNA for solid tumor therapy.

mRNA vaccine for cancer immunotherapy

mRNA vaccines have become a promising platform for cancer immunotherapy. During vaccination, naked or vehicle loaded mRNA vaccines efficiently express tumor antigens in antigen-presenting cells (APCs), facilitate APC activation and innate/adaptive immune stimulation. mRNA cancer vaccine precedes other conventional vaccine platforms due to high potency, safe administration, rapid development potentials, and cost-effective manufacturing. However, mRNA vaccine applications have been limited by instability, innate immunogenicity, and inefficient in vivo delivery. Appropriate mRNA structure modifications (i.e., codon optimizations, nucleotide modifications, self-amplifying mRNAs, etc.) and formulation methods (i.e., lipid nanoparticles (LNPs), polymers, peptides, etc.) have been investigated to overcome these issues. Tuning the administration routes and co-delivery of multiple mRNA vaccines with other immunotherapeutic agents (e.g., checkpoint inhibitors) have further boosted the host anti-tumor immunity and increased the likelihood of tumor cell eradication. With the recent U.S. Food and Drug Administration (FDA) approvals of LNP-loaded mRNA vaccines for the prevention of COVID-19 and the promising therapeutic outcomes of mRNA cancer vaccines achieved in several clinical trials against multiple aggressive solid tumors, we envision the rapid advancing of mRNA vaccines for cancer immunotherapy in the near future. This review provides a detailed overview of the recent progress and existing challenges of mRNA cancer vaccines and future considerations of applying mRNA vaccine for cancer immunotherapies.

Adjuvant-pulsed mRNA vaccine nanoparticle for immunoprophylactic and therapeutic tumor suppression in mice

Synthetic mRNA represents an exciting cancer vaccine technology for the implementation of effective cancer immunotherapy. However, inefficient in vivo mRNA delivery along with a requirement for immune co-stimulation present major hurdles to achieving anti-tumor therapeutic efficacy. Here, we demonstrate a proof-of-concept adjuvant-pulsed mRNA vaccine nanoparticle (NP) that is composed of an ovalbumin-coded mRNA and a palmitic acid-modified TLR7/8 agonist R848 (C16-R848), coated with a lipid-polyethylene glycol (lipid-PEG) shell. This mRNA vaccine NP formulation retained the adjuvant activity of encapsulated C16-R848 and markedly improved the transfection efficacy of the mRNA (>95%) and subsequent MHC class I presentation of OVA mRNA derived antigen in antigen-presenting cells. The C16-R848 adjuvant-pulsed mRNA vaccine NP approach induced an effective adaptive immune response by significantly improving the expansion of OVA-specific CD8+ T cells and infiltration of these cells into the tumor bed in vivo, relative to the mRNA vaccine NP without adjuvant. The approach led to an effective anti-tumor immunity against OVA expressing syngeneic allograft mouse models of lymphoma and prostate cancer, resulting in a significant prevention of tumor growth when the vaccine was given before tumor engraftment (84% reduction vs. control) and suppression of tumor growth when given post engraftment (60% reduction vs. control). Our findings indicate that C16-R848 adjuvant pulsation to mRNA vaccine NP is a rational design strategy to increase the effectiveness of synthetic mRNA vaccines for cancer immunotherapy.

Biomaterials to enhance antigen-specific T cell expansion for cancer immunotherapy

T cells are often referred to as the 'guided missiles' of our immune system because of their capacity to traffic to and accumulate at sites of infection or disease, destroy infected or mutated cells with high specificity and sensitivity, initiate systemic immune responses, sterilize infections, and produce long-lasting memory. As a result, they are a common target for a range of cancer immunotherapies. However, the myriad of challenges of expanding large numbers of T cells specific to each patient's unique tumor antigens has led researchers to develop alternative, more scalable approaches. Biomaterial platforms for expansion of antigen-specific T cells offer a path forward towards broadscale translation of personalized immunotherapies by providing "off-the-shelf", yet modular approaches to customize the phenotype, function, and specificity of T cell responses. In this review, we discuss design considerations and progress made in the development of ex vivo and in vivo technologies for activating antigen-specific T cells, including artificial antigen presenting cells, T cell stimulating scaffolds, biomaterials-based vaccines, and artificial lymphoid organs. Ultimate translation of these platforms as a part of cancer immunotherapy regimens hinges on an in-depth understanding of T cell biology and cell-material interactions.