Engineering Magnetosomes for High-Performance Cancer Vaccination

Recent progress in cancer vaccines and nanovaccines

Vaccine science, nanotechnology, and immunotherapy are at the forefront of cancer treatment strategies, each offering significant potential for enhancing tumor-specific immunity and establishing long-lasting immune memory to prevent tumor recurrence. Despite the promise of these personalized and precision-based anti-cancer approaches, challenges such as immunosuppression, suboptimal immune activation, and T-cell exhaustion continue to hinder their effectiveness. The limited clinical success of cancer vaccines often stems from difficulties in identifying effective antigens, efficiently targeting immune cells, lymphoid organs, and the tumor microenvironment, overcoming immune evasion, enhancing immunogenicity, and avoiding lysosomal degradation. However, numerous studies have demonstrated that integrating nanotechnology with immunotherapeutic strategies in vaccine development can overcome these challenges, leading to potent antitumor immune responses and significant progress in the field. This review highlights the critical components of cancer vaccine and nanovaccine strategies for immunomodulatory antitumor therapy. It covers general vaccine strategies, types of vaccines, antigen forms, nanovaccine platforms, challenges faced, potential solutions, and key findings from preclinical and clinical studies, along with future perspectives. To fully unlock the potential of cancer vaccines and nanovaccines, precise immunological monitoring during early-phase trials is essential. This approach will help identify and address obstacles, ultimately expanding the available options for patients who are resistant to conventional cancer immunotherapies.

Bacterial nanotechnology as a paradigm in targeted cancer therapeutic delivery and immunotherapy

Cancer, a multifaceted and diverse ailment, presents formidable obstacles to traditional treatment modalities. Nanotechnology presents novel prospects for surmounting these challenges through its capacity to facilitate meticulous and regulated administration of therapeutic agents to malignant cells while concurrently modulating the immune system to combat neoplasms. Bacteria and their derivatives have emerged as highly versatile and multifunctional platforms for cancer nanotherapy within the realm of nanomaterials. This comprehensive review delves into the multifaceted and groundbreaking implementations of bacterial nanotechnology within cancer therapy. This review encompasses four primary facets: the utilization of bacteria as living conveyors of medicinal substances, the employment of bacterial components as agents that stimulate the immune system, the deployment of bacterial vectors as tools for delivering genetic material, and the development of bacteria-derived nano-drugs as intelligent nano-medications. Furthermore, we elucidate the merits and modalities of operation pertaining to these bacterial nano-systems, along with their capacity to synergize with other cutting-edge nanotechnologies, such as CRISPR-Cas systems. Additionally, we offer insightful viewpoints regarding the forthcoming trajectories and prospects within this expanding domain. It is our deduction that bacterial nanotechnology embodies a propitious and innovative paradigm in the realm of cancer therapy, which has the potential to provide numerous advantages and synergistic effects in enhancing the outcomes and quality of life for individuals afflicted with cancer.

Application of biomimetic nanovaccines in cancer immunotherapy: A useful strategy to help combat immunotherapy resistance

Breakthroughs in actual clinical applications have begun through vaccine-based cancer immunotherapy, which uses the body's immune system, both humoral and cellular, to attack malignant cells and fight diseases. However, conventional vaccine approaches still face multiple challenges eliciting effective antigen-specific immune responses, resulting in immunotherapy resistance. In recent years, biomimetic nanovaccines have emerged as a promising alternative to conventional vaccine approaches by incorporating the natural structure of various biological entities, such as cells, viruses, and bacteria. Biomimetic nanovaccines offer the benefit of targeted antigen-presenting cell (APC) delivery, improved antigen/adjuvant loading, and biocompatibility, thereby improving the sensitivity of immunotherapy. This review presents a comprehensive overview of several kinds of biomimetic nanovaccines in anticancer immune response, including cell membrane-coated nanovaccines, self-assembling protein-based nanovaccines, extracellular vesicle-based nanovaccines, natural ligand-modified nanovaccines, artificial antigen-presenting cells-based nanovaccines and liposome-based nanovaccines. We also discuss the perspectives and challenges associated with the clinical translation of emerging biomimetic nanovaccine platforms for sensitizing cancer cells to immunotherapy.

Convergence of Nanotechnology and Bacteriotherapy for Biomedical Applications

Bacteria have distinctive properties that make them ideal for biomedical applications. They can self-propel, sense their surroundings, and be externally detected. Using bacteria as medical therapeutic agents or delivery platforms opens new possibilities for advanced diagnosis and therapies. Nano-drug delivery platforms have numerous advantages over traditional ones, such as high loading capacity, controlled drug release, and adaptable functionalities. Combining bacteria and nanotechnologies to create therapeutic agents or delivery platforms has gained increasing attention in recent years and shows promise for improved diagnosis and treatment of diseases. In this review, design principles of integrating nanoparticles with bacteria, bacteria-derived nano-sized vesicles, and their applications and future in advanced diagnosis and therapeutics are summarized.

Cancer cell membrane-coated nanoparticles: a promising anti-tumor bionic platform

Nanoparticle (NP) drug delivery systems have shown promise in tumor therapy. However, limitations such as susceptibility to immune clearance and poor targeting in a complex intercellular environment still exist. Recently, cancer cell membrane-encapsulated nanoparticles (CCM-NPs) constructed using biomimetic nanotechnology have been developed to overcome these problems. Proteins on the membrane surface of cancer cells can provide a wide range of activities for CCM-NPs, including immune escape and homologous cell recognition properties. Meanwhile, the surface of the cancer cell membrane exhibits obvious antigen enrichment, so that CCM-NPs can transmit tumor-specific antigen, activate a downstream immune response, and produce an effective anti-tumor effect. In this review, we first provided an overview of the functions of cancer cell membranes and summarized the preparation techniques and characterization methods of CCM-NPs. Then, we focused on the application of CCM-NPs in tumor therapy. In addition, we summarized the functional modifications of cancer cell membranes and compiled the patent applications related to CCM-NPs in recent years. Finally, we proposed the future challenges and directions of this technology in order to provide guidance for researchers in this field.

Nanomaterial Delivery Vehicles for the Development of Neoantigen Tumor Vaccines for Personalized Treatment

Tumor vaccines have been considered a promising therapeutic approach for treating cancer in recent years. With the development of sequencing technologies, tumor vaccines based on neoantigens or genomes specifically expressed in tumor cells, mainly in the form of peptides, nucleic acids, and dendritic cells, are beginning to receive widespread attention. Therefore, in this review, we have introduced different forms of neoantigen vaccines and discussed the development of these vaccines in treating cancer. Furthermore, neoantigen vaccines are influenced by factors such as antigen stability, weak immunogenicity, and biosafety in addition to sequencing technology. Hence, the biological nanomaterials, polymeric nanomaterials, inorganic nanomaterials, etc., used as vaccine carriers are principally summarized here, which may contribute to the design of neoantigen vaccines for improved stability and better efficacy.

Engineered Cell Membrane-Camouflaged Nanomaterials for Biomedical Applications

Recent strides in nanomaterials science have paved the way for the creation of reliable, effective, highly accurate, and user-friendly biomedical systems. Pioneering the integration of natural cell membranes into sophisticated nanocarrier architectures, cell membrane camouflage has emerged as a transformative approach for regulated drug delivery, offering the benefits of minimal immunogenicity coupled with active targeting capabilities. Nevertheless, the utility of nanomaterials with such camouflage is curtailed by challenges like suboptimal targeting precision and lackluster therapeutic efficacy. Tailored cell membrane engineering stands at the forefront of biomedicine, equipping nanoplatforms with the capacity to conduct more complex operations. This review commences with an examination of prevailing methodologies in cell membrane engineering, spotlighting strategies such as direct chemical modification, lipid insertion, membrane hybridization, metabolic glycan labeling, and genetic engineering. Following this, an evaluation of the unique attributes of various nanomaterials is presented, delivering an in-depth scrutiny of the substantial advancements and applications driven by cutting-edge engineered cell membrane camouflage. The discourse culminates by recapitulating the salient influence of engineered cell membrane camouflage within nanomaterial applications and prognosticates its seminal role in transformative healthcare technologies. It is envisaged that the insights offered herein will catalyze novel avenues for the innovation and refinement of engineered cell membrane camouflaged nanotechnologies.

Materials-Based Approaches for Cancer Vaccination

Therapeutic cancer vaccines offer the promise of stimulating the immune system to specifically eradicate tumor cells and establish long-term memory to prevent tumor recurrence. However, despite showing benign safety profiles and the ability to generate Ag-specific cellular responses, cancer vaccines have been hampered by modest clinical efficacy. Lessons learned from these studies have led to the emergence of innovative materials-based strategies that aim to boost the clinical activity of cancer vaccines. In this Brief Review, we provide an overview of the key elements needed for an effective vaccine-induced antitumor response, categorize current approaches to therapeutic cancer vaccination, and explore recent advances in materials-based strategies to potentiate cancer vaccines.

Neuroprotective Effects of Microglial Membrane-Derived Biomimetic Particles for Spinal Cord Injury

Inhibition of oxidative stress and inflammatory responses caused by secondary injury following traumatic spinal cord injury (SCI) is an attractive strategy in treating traumatic SCI. However, the efficacy of drugs is severely limited owing to the poor penetration of the blood spinal cord barrier (BSCB). Here, inspired by cell chemotaxis and related chemokines production at the lesion sites of SCI, the microglial membrane is selected to construct a drug delivery system with the ability to cross the BSCB and target the lesions. PR@MM is prepared based on the assembly of polylactic-co-glycolic acid (PLGA) and resveratrol (RSV) followed by microglial membrane (MM) coating. Compared to that of the uncoated nanoparticles, the enrichment of PR@MM at the lesion sites of SCI increases, which is beneficial to achieve lesion targeting of RSV and exert therapeutic functions. Both in vitro and in vivo experiments demonstrate that PR@MM has the ability to scavenge reactive oxygen species and anti-inflammatory effects, which ultimately promotes the recovery of locomotory function after SCI. Therefore, this microglial membrane-based drug delivery system provides a promising biomimetic nanomedicine for targeted therapy for SCI.

Lymph node targeting for immunotherapy

Immunotherapy that aims to boost the body's immune responses against pathogens or diseased cells has achieved significant progress for treating different diseases over the past several decades, especially with the success of checkpoint blockades, chimeric antigen receptor T therapy, and cancer vaccines in clinical cancer treatment. Effective immunotherapy necessitates the generation of potent and persistent humoral and T-cell responses, which lies in the ability of modulating and guiding antigen-presenting cells to prime antigen-specific T and B cells in the lymphoid tissues, notably in the lymph nodes proximal to the disease site. To this end, various types of strategies have been developed to facilitate the delivery of immunomodulatory agents to immune cells (e.g. dendritic cells and T cells) in the lymph nodes. Among them, intranodal injection enables the direct exposure of immunomodulators to immune cells in lymph nodes, but is limited by the technical challenge and intrinsic invasiveness. To address, multiple passive and active lymph node-targeting technologies have been developed. In this review, we will provide an overview of different lymph node-targeting technologies developed to date, as well as the mechanism and merits of each approach.

Fused Cytomembrane-Camouflaged Nanoparticles for Tumor-Specific Immunotherapy

Tumor immunotherapy is commonly hindered by inefficient delivery and presentation of tumor antigens as well as immunosuppressive tumor microenvironment. To overcome these barriers, a tumor-specific nanovaccine capable of delivering tumor antigens and adjuvants to antigen-presenting cells and modulating the immune microenvironment to elicit strong antitumor immunity is reported. This nanovaccine, named FCM@4RM, is designed by coating the nanocore (FCM) with a bioreconstituted cytomembrane (4RM). The 4RM, which is derived from fused cells of tumorous 4T1 cells and RAW264.7 macrophages, enables effective antigen presentation and stimulation of effector T cells. FCM is self-assembled from Fe(II), unmethylated cytosine-phosphate-guanine oligodeoxynucleotide (CpG), and metformin (MET). CpG, as the stimulator of toll-like receptor 9, induces the production of pro-inflammatory cytokine and the maturation of cytotoxic T lymphocytes (CTLs), thereby enhancing antitumor immunity. Meanwhile, MET functions as the programmed cell death ligand 1 inhibitor and can restore the immune responses of T cells against tumor cells. Therefore, FCM@4RM exhibits high targeting capabilities toward homologous tumors that develop from 4T1 cells. This work offers a paradigm for developing a nanovaccine that systematically regulates multiple immune-related processes to achieve optimal antitumor immunotherapy.

Advances in nanomedicines for lymphatic imaging and therapy

Lymph nodes play a pivotal role in tumor progression as key components of the lymphatic system. However, the unique physiological structure of lymph nodes has traditionally constrained the drug delivery efficiency. Excitingly, nanomedicines have shown tremendous advantages in lymph node-specific delivery, enabling distinct recognition and diagnosis of lymph nodes, and hence laying the foundation for efficient tumor therapies. In this review, we comprehensively discuss the key factors affecting the specific enrichment of nanomedicines in lymph nodes, and systematically summarize nanomedicines for precise lymph node drug delivery and therapeutic application, including the lymphatic diagnosis and treatment nanodrugs and lymph node specific imaging and identification system. Notably, we delve into the critical challenges and considerations currently facing lymphatic nanomedicines, and futher propose effective strategies to address these issues. This review encapsulates recent findings, clinical applications, and future prospects for designing effective nanocarriers for lymphatic system targeting, with potential implications for improving cancer treatment strategies.

Rethinking Antigen Source: Cancer Vaccines Based on Whole Tumor Cell/tissue Lysate or Whole Tumor Cell

Cancer immunotherapies have improved human health, and one among the important technologies for cancer immunotherapy is cancer vaccine. Antigens are the most important components in cancer vaccines. Generally, antigens in cancer vaccines can be divided into two categories: pre-defined antigens and unidentified antigens. Although, cancer vaccines loaded with predefined antigens are commonly used, cancer vaccine loaded with mixed unidentified antigens, especially whole cancer cells or cancer cell lysates, is a very promising approach, and such vaccine can obviate some limitations in cancer vaccines. Their advantages include, but are not limited to, the inclusion of pan-spectra (all or most kinds of) antigens, inducing pan-clones specific T cells, and overcoming the heterogeneity of cancer cells. In this review, the recent advances in cancer vaccines based on whole-tumor antigens, either based on whole cancer cells or whole cancer cell lysates, are summarized. In terms of whole cancer cell lysates, the focus is on applying whole water-soluble cell lysates as antigens. Recently, utilizing the whole cancer cell lysates as antigens in cancer vaccines has become feasible. Considering that pre-determined antigen-based cancer vaccines (mainly peptide-based or mRNA-based) have various limitations, developing cancer vaccines based on whole-tumor antigens is a promising alternative.

Nanovaccine-based strategies for lymph node targeted delivery and imaging in tumor immunotherapy

Therapeutic tumor vaccines have attracted considerable attention in the past decade; they can induce tumor regression, eradicate minimal residual disease, establish lasting immune memory and avoid non-specific and adverse side effects. However, the challenge in the field of therapeutic tumor vaccines is ensuring the delivery of immune components to the lymph nodes (LNs) to activate immune cells. The clinical response rate of traditional therapeutic tumor vaccines falls short of expectations due to inadequate lymph node delivery. With the rapid development of nanotechnology, a large number of nanoplatform-based LN-targeting nanovaccines have been exploited for optimizing tumor immunotherapies. In addition, some nanovaccines possess non-invasive visualization performance, which is benefit for understanding the kinetics of nanovaccine exposure in LNs. Herein, we present the parameters of nanoplatforms, such as size, surface modification, shape, and deformability, which affect the LN-targeting functions of nanovaccines. The recent advances in nanoplatforms with different components promoting LN-targeting are also summarized. Furthermore, emerging LNs-targeting nanoplatform-mediated imaging strategies to both improve targeting performance and enhance the quality of LN imaging are discussed. Finally, we summarize the prospects and challenges of nanoplatform-based LN-targeting and /or imaging strategies, which optimize the clinical efficacy of nanovaccines in tumor immunotherapies.

Biomaterials Facilitating Dendritic Cell-Mediated Cancer Immunotherapy

Dendritic cell (DC)-based cancer immunotherapy has exhibited remarkable clinical prospects because DCs play a central role in initiating and regulating adaptive immune responses. However, the application of traditional DC-mediated immunotherapy is limited due to insufficient antigen delivery, inadequate antigen presentation, and high levels of immunosuppression. To address these challenges, engineered biomaterials have been exploited to enhance DC-mediated immunotherapeutic effects. In this review, vital principal components that can enhance DC-mediated immunotherapeutic effects are first introduced. The parameters considered in the rational design of biomaterials, including targeting modifications, size, shape, surface, and mechanical properties, which can affect biomaterial optimization of DC functions, are further summarized. Moreover, recent applications of various engineered biomaterials in the field of DC-mediated immunotherapy are reviewed, including those serve as immune component delivery platforms, remodel the tumor microenvironment, and synergistically enhance the effects of other antitumor therapies. Overall, the present review comprehensively and systematically summarizes biomaterials related to the promotion of DC functions; and specifically focuses on the recent advances in biomaterial designs for DC activation to eradicate tumors. The challenges and opportunities of treatment strategies designed to amplify DCs via the application of biomaterials are discussed with the aim of inspiring the clinical translation of future DC-mediated cancer immunotherapies.

Virus-like Magnetic Mesoporous Silica Particles as a Universal Vaccination Platform against Pathogenic Infections

Vaccination is the most important way of population protection from life-threatening pathogenic infections. However, its efficiency is frequently compromised by a failure of strong antigen presentation and immune activation. Herein, we developed virus-like magnetic mesoporous silica nanoparticles as a universal vaccination platform (termed MagParV) for preventing pathogenic infections. This platform was constructed by integrating synthetic biology-based endoplasmic reticulum-targeting vesicles with magnetic mesoporous silica particles. This platform exhibited high antigen-loading capacity, strongly targeting the endoplasmic reticulum and promoting antigen presentation in dendritic cells. After prime-boost vaccination, the antigen-loading MagParV with AMF drastically elicited specific antibody production against corresponding antigens of fungal, bacterial, and viral pathogens. A systemic infection model further revealed that the platform effectively protected the mice from severe fungal systemic infections. This study realized synthetic biology-facilitated green manufacturing of vaccines, which is promising for magnetism-activated vaccination against different kinds of pathogenic infections.

Combined Cancer Immunotheranostic Nanomedicines: Delivery Technologies and Therapeutic Outcomes

Cancer is among the main causes of mortality all over the world. The delayed diagnosis is directly related to the decrease in survival rate. The use of immunotherapy has dramatically changed the treatment outcomes of different types of cancers. However, many patients still do not respond to immunotherapies, and many also suffer from severe immune-related side effects. Recent advances in the fields of nanomedicine bioengineering and in particular imaging offered new approaches which can enhance not only the safety but also the efficacy of immunotherapy. Theranostics has showed great progress as a branch of medicine which integrates both diagnosis and therapy in a single system. The outcomes from animal studies demonstrated an improvement in the diagnostic and immunotherapeutic potential of nanoparticles within the theranostic framework. Herein, we discuss the most recent developments in the application of nanotheranostics for combining tumor imaging and cancer immunotherapies.

In-depth review of delivery carriers associated with vaccine adjuvants: current status and future perspectives

INTRODUCTION

Vaccines are powerful tools for controlling microbial infections and preventing epidemics. To enhance the immune response to antigens, effective subunit vaccines or mRNA vaccines often require the combination of adjuvants or delivery carriers. In recent years, with the rapid development of immune mechanism research and nanotechnology, various studies based on the optimization of traditional adjuvants or various novel carriers have been intensified, and the construction of vaccine adjuvant delivery systems (VADS) with both adjuvant activity and antigen delivery has become more and more important in vaccine research.

AREAS COVERED

This paper reviews the common types of vaccine adjuvant delivery carriers, classifies the VADS according to their basic carrier types, introduces the current research status and future development trend, and emphasizes the important role of VADS in novel vaccine research.

EXPERT OPINION

As the number of vaccine types increases, conventional aluminum adjuvants show limitations in effectively stimulating cellular immune responses, limiting their use in therapeutic vaccines for intracellular infections or tumors. In contrast, the use of conventional adjuvants as VADS to carry immunostimulatory molecules or deliver antigens can greatly enhance the immune boosting effect of classical adjuvants. A comprehensive understanding of the various delivery vehicles will further facilitate the development of vaccine adjuvant research.

Nanoenabled Trainable Systems: From Biointerfaces to Biomimetics

In the dynamic biological system, cells and tissues adapt to diverse environmental conditions and form memories, an essential aspect of training for survival and evolution. An understanding of the biological training principles will inform the design of biomimetic materials whose properties evolve with the environment and offer routes to programmable soft materials, neuromorphic computing, living materials, and biohybrid robotics. In this perspective, we examine the mechanisms by which cells are trained by environmental cues. We outline the artificial platforms that enable biological training and examine the relationship between biological training and biomimetic materials design. We place emphasis on nanoscale material platforms which, given their applicability to chemical, mechanical and electrical stimulation, are critical to bridging natural and synthetic systems.

Recent advances in developing active targeting and multi-functional drug delivery systems via bioorthogonal chemistry

Bioorthogonal chemistry reactions occur in physiological conditions without interfering with normal physiological processes. Through metabolic engineering, bioorthogonal groups can be tagged onto cell membranes, which selectively attach to cargos with paired groups via bioorthogonal reactions. Due to its simplicity, high efficiency, and specificity, bioorthogonal chemistry has demonstrated great application potential in drug delivery. On the one hand, bioorthogonal reactions improve therapeutic agent delivery to target sites, overcoming off-target distribution. On the other hand, nanoparticles and biomolecules can be linked to cell membranes by bioorthogonal reactions, providing approaches to developing multi-functional drug delivery systems (DDSs). In this review, we first describe the principle of labeling cells or pathogenic microorganisms with bioorthogonal groups. We then highlight recent breakthroughs in developing active targeting DDSs to tumors, immune systems, or bacteria by bioorthogonal chemistry, as well as applications of bioorthogonal chemistry in developing functional bio-inspired DDSs (biomimetic DDSs, cell-based DDSs, bacteria-based and phage-based DDSs) and hydrogels. Finally, we discuss the difficulties and prospective direction of bioorthogonal chemistry in drug delivery. We expect this review will help us understand the latest advances in the development of active targeting and multi-functional DDSs using bioorthogonal chemistry and inspire innovative applications of bioorthogonal chemistry in developing smart DDSs for disease treatment.

Lymph node-targeting nanovaccines for cancer immunotherapy

Cancer immunotherapies such as tumor vaccines, chimeric antigen receptor T cells and immune checkpoint blockades, have attracted tremendous attention. Among them, tumor vaccines prime immune response by delivering antigens and adjuvants to the antigen presenting cells (APCs), thus enhancing antitumor immunotherapy. Despite tumor vaccines have made considerable achievements in tumor immunotherapy, it remains challenging to efficiently deliver tumor vaccines to activate the dendritic cells (DCs) in lymph nodes (LNs). Rational design of nanovaccines on the basis of biomedical nanotechnology has emerged as one of the most promising strategies for boosting the outcomes of cancer immunotherapy. In recent years, great efforts have been made in exploiting various nanocarrier-based LNs-targeting tumor nanovaccines. In view of the rapid advances in this field, we here aim to summarize the latest progression in LNs-targeting nanovaccines for cancer immunotherapy, with special attention to various nano-vehicles developed for LNs-targeting delivery of tumor vaccines, including lipid-based nanoparticles, polymeric nanocarriers, inorganic nanocarriers and biomimetic nanosystems. Moreover, the recent trends in nanovaccines-based combination cancer immunotherapy are provided. Finally, the rationality, advantages and challenges of LNs-targeting nanovaccines for clinical translation and application are spotlighted.

Tumor-Derived Membrane Vesicles: A Promising Tool for Personalized Immunotherapy

Tumor-derived membrane vesicles (TDMVs) are non-invasive, chemotactic, easily obtained characteristics and contain various tumor-borne substances, such as nucleic acid and proteins. The unique properties of tumor cells and membranes make them widely used in drug loading, membrane fusion and vaccines. In particular, personalized vectors prepared using the editable properties of cells can help in the design of personalized vaccines. This review focuses on recent research on TDMV technology and its application in personalized immunotherapy. We elucidate the strengths and challenges of TDMVs to promote their application from theory to clinical practice.

Image-guided/improved diseases management: From immune-strategies and beyond

Timely and accurate assessment and diagnosis are extremely important and beneficial for all diseases, especially for some of the major human disease, such as cancers, cardiovascular diseases, infectious diseases, and neurodegenerative diseases. Limited by the variable disease microenvironment, early imperceptible symptoms, complex immune system interactions, and delayed clinical phenotypes, disease diagnosis and treatment are difficult in most cases. Molecular imaging (MI) techniques can track therapeutic drugs and disease sites in vivo and in vitro in a non-invasive, real-time and visible strategies. Comprehensive visual imaging and quantitative analysis based on different levels can help to clarify the disease process, pathogenesis, drug pharmacokinetics, and further evaluate the therapeutic effects. This review summarizes the application of different MI techniques in the diagnosis and treatment of these major human diseases. It is hoped to shed a light on the development of related technologies and fields.

Polymerized porin as a novel delivery platform for coronavirus vaccine

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), seriously threatens human life and health. The correct folding and polymerization of the receptor-binding domain (RBD) protein of coronavirus in Escherichia coli may reduce the cost of SARS-CoV-2 vaccines. In this study, we constructed this nanopore by using the principle of ClyA porin polymerization triggered by the cell membrane. We used surfactants to "pick" the ClyA-RBD nanopore from the bacterial outer membrane. More importantly, the polymerized RBD displayed on the ClyA-RBD polymerized porin (RBD-PP) already displays some correct spatial conformational epitopes that can induce neutralizing antibodies. The nanostructures of RBD-PP can target lymph nodes and promote antigen uptake and processing by dendritic cells, thereby effectively eliciting the production of anti-SARS-CoV-2 neutralizing antibodies, systemic cellular immune responses, and memory T cells. We applied this PP-based vaccine platform to fabricate an RBD-based subunit vaccine against SARS-CoV-2, which will provide a foundation for the development of inexpensive coronavirus vaccines. The development of a novel vaccine delivery system is an important part of innovative drug research. This novel PP-based vaccine platform is likely to have additional applications, including other viral vaccines, bacterial vaccines, tumor vaccines, drug delivery, and disease diagnosis.

Bacteria-based nanodrug for anticancer therapy

Bacteria-based immunotherapy has become a promising strategy to induce innate and adaptive responses for fighting cancer. The advantages of bacteriolytic tumor therapy mainly lie in stimulation of innate immunity and colonization of some bacteria targeting the tumor microenvironment (TME). These bacteria have cytotoxic proteins and immune modulating factors that can effectively restrain tumor growth. However, cancer is a multifactorial disease and single therapy is typically unable to eradicate tumors. Rapid progress has been made in combining bacteria with nanotechnology. Using the nanomolecular properties of bacterial products for tumor treatment preserves many features from the original bacteria while providing some unique advantages. Nano-bacterial therapy can enhance permeability and retention of drugs, increase the tolerability of the targeted drugs, promote the release of immune cell mediators, and induce immunogenic cell death pathways. In addition, combining nano-bacterial mediated antitumor therapeutic systems with modern therapy is an effective strategy for overcoming existing barriers in antitumor treatment and can achieve satisfactory therapeutic efficacy. Overall, exploring the immune antitumor characteristics of adjuvant clinical treatment with bacteria can provide potential efficacious treatment strategies for combatting cancer.

Cell-derived membrane biomimetic nanocarriers for targeted therapy of pulmonary disease

Pulmonary diseases are currently one of the major threats of human health, especially considering the recent COVID-19 pandemic. However, the current treatments are facing the challenges like insufficient local drug concentrations, the fast lung clearance and risks to induce unexpected inflammation. Cell-derived membrane biomimetic nanocarriers are recently emerged delivery strategy, showing advantages of long circulation time, excellent biocompatibility and immune escape ability. In this review, applications of using cell-derived membrane biomimetic nanocarriers from diverse cell sources for the targeted therapy of pulmonary disease were summarized. In addition, improvements of the cell-derived membrane biomimetic nanocarriers for augmented therapeutic ability against different kinds of pulmonary diseases were introduced. This review is expected to provide a general guideline for the potential applications of cell-derived membrane biomimetic nanocarriers to treat pulmonary diseases.

Triggering Immune System With Nanomaterials for Cancer Immunotherapy

Cancer is a major cause of incidence rate and mortality worldwide. In recent years, cancer immunotherapy has made great progress in the preclinical and clinical treatment of advanced malignant tumors. However, cancer patients will have transient cancer suppression reaction and serious immune related adverse reactions when receiving immunotherapy. In recent years, nanoparticle-based immunotherapy, which can accurately deliver immunogens, activate antigen presenting cells (APCs) and effector cells, provides a new insight to solve the above problems. In this review, we discuss the research progress of nanomaterials in immunotherapy including nanoparticle-based delivery systems, nanoparticle-based photothermal and photodynamic immunotherapy, nanovaccines, nanoparticle-based T cell cancer immunotherapy and nanoparticle-based bacteria cancer immunotherapy. We also put forward the current challenges and prospects of immunomodulatory therapy.

Nanovaccines with cell-derived components for cancer immunotherapy

Cancer nanovaccines as one of immunotherapeutic approaches are able to attack tumors by stimulating tumor-specific immunological responses. However, there still exist multiple challenges to be tackled for cancer nanovaccines to evoke potent antitumor immunity. Particularly, the administration of exogenous materials may cause the off-target immunotherapy responses. In recent years, biomimetic nanovaccines by using cell lysates, cell-derived nanovesicles, or extracted cell membranes as the functional components have received extensive attention. Such nanovaccines based on cell-derived components would show many unique advantages including inherent biocompatibility and the ability to trigger immune responses against a range of tumor-associated antigens. In this review article, we will introduce the recent research progresses of those cell-derived biomimetic nanovaccines for cancer immunotherapy, and discuss the perspectives and challenges associated with the future clinical translation of these emerging vaccine platforms.

Metal-free bioorthogonal click chemistry in cancer theranostics

Bioorthogonal chemistry is a powerful tool to site-specifically activate drugs in living systems. Bioorthogonal reactions between a pair of biologically reactive groups can rapidly and specifically take place in a mild physiological milieu without perturbing inherent biochemical processes. Attributed to their high selectivity and efficiency, bioorthogonal reactions can significantly decrease background signals in bioimaging. Compared with metal-catalyzed bioorthogonal click reactions, metal-free click reactions are more biocompatible without the metal catalyst-induced cytotoxicity. Although a great number of bioorthogonal chemistry-based strategies have been reported for cancer theranostics, a comprehensive review is scarce to highlight the advantages of these strategies. In this review, recent progress in cancer theranostics guided by metal-free bioorthogonal click chemistry will be depicted in detail. The elaborate design as well as the advantages of bioorthogonal chemistry in tumor theranostics are summarized and future prospects in this emerging field are emphasized.

Transformable vesicles for cancer immunotherapy

Immunotherapy that utilizes the human immune system to fight cancer represents a revolutionary method for cancer treatment. Immunotherapeutic agents that trigger the immune response should be carefully delivered to the desired site to maximize immunotherapy effectiveness and minimize side effects. Vesicles offer the possibility of encapsulating both hydrophilic and hydrophobic drugs and thus serve as a promising delivery tool. As multiple irreconcilable requirements exist at different transport stages, developing vesicles transformable in response to given stimuli is of great significance. In this review, we first introduced various vesicle types used for immunotherapy. Furthermore, the typical stimuli that trigger vesicle transformation and the usually generated transformation styles were described. Focusing on three aspects of antigen-presenting cell (APC)/T cell activation, tumor microenvironment (TME) amelioration, and immunogenic cell death (ICD)-induced immunotherapy, we reviewed recently reported transformable vesicles for tumor treatment. Finally, we put forward possible directions for future research and clinical translation.

Nanotechnology-enhanced immunotherapy for metastatic cancer

A vast majority of cancer deaths occur as a result of metastasis. Unfortunately, effective treatments for metastases are currently lacking due to the difficulty of selectively targeting these small, delocalized tumors distributed across a variety of organs. However, nanotechnology holds tremendous promise for improving immunotherapeutic outcomes in patients with metastatic cancer. In contrast to conventional cancer immunotherapies, rationally designed nanomaterials can trigger specific tumoricidal effects, thereby improving immune cell access to major sites of metastasis such as bone, lungs, and lymph nodes, optimizing antigen presentation, and inducing a persistent immune response. This paper reviews the cutting-edge trends in nano-immunoengineering for metastatic cancers with an emphasis on different nano-immunotherapeutic strategies. Specifically, it discusses directly reversing the immunological status of the primary tumor, harnessing the potential of peripheral immune cells, preventing the formation of a pre-metastatic niche, and inhibiting the tumor recurrence through postoperative immunotherapy. Finally, we describe the challenges facing the integration of nanoscale immunomodulators and provide a forward-looking perspective on the innovative nanotechnology-based tools that may ultimately prove effective at eradicating metastatic diseases.

Applications of Magnetite Nanoparticles in Cancer Immunotherapies: Present Hallmarks and Future Perspectives

Current immuno-oncotherapeutic protocols that inhibit tumor immune evasion have demonstrated great clinical success. However, the therapeutic response is limited only to a percentage of patients, and the immune-related adverse events can compromise the therapeutic benefits. Therefore, improving cancer immunotherapeutic approaches that pursue high tumor suppression efficiency and low side effects turn out to be a clinical priority. Novel magnetite nanoparticles (MNPs) exhibit great potential for therapeutic and imaging applications by utilizing their properties of superparamagnetism, good biocompatibility, as well as the easy synthesis and modulation/functionalization. In particular, the MNPs can exert magnetic hyperthermia to induce immunogenic cell death of tumor cells for effective antigen release and presentation, and meanwhile polarize tumor-associated macrophages (TAMs) to M1 phenotype for improved tumor killing capability, thus enhancing the anti-tumor immune effects. Furthermore, immune checkpoint antibodies, immune-stimulating agents, or tumor-targeting agents can be decorated on MNPs, thereby improving their selectivity for the tumor or immune cells by the unique magnetic navigation capability of MNPs to promote the tumor killing immune therapeutics with fewer side effects. This mini-review summarizes the recent progress in MNP-based immuno-oncotherapies, including activation of macrophage, promotion of cytotoxic T lymphocyte (CTL) infiltration within tumors and modulation of immune checkpoint blockade, thus further supporting the applications of MNPs in clinical therapeutic protocols.

Enhancing therapeutic performance of personalized cancer vaccine via delivery vectors

In recent years, personalized cancer vaccines have gained increasing attention as emerging immunotherapies with the capability to overcome interindividual differences and show great benefits for individual patients in the clinic due to the highly tailored vaccine formulations. A large number of materials have been studied as delivery vectors to enhance the therapeutic performance of personalized cancer vaccines, including artificial materials, engineered microorganisms, cells and cell derivatives. These delivery vectors with distinct features are employed to change antigen biodistributions and to facilitate antigen uptake, processing and presentation, improving the strength, velocity, and duration of the immune response when delivered by different strategies. Here, we provide an overview of personalized cancer vaccine delivery vectors, describing their materials, physicochemical properties, delivery strategies and challenges for clinical transformation.

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.

Dynamic nanoassembly-based drug delivery system (DNDDS): Learning from nature

Dynamic nanoassembly-based drug delivery system (DNDDS) has evolved from being a mere curiosity to emerging as a promising strategy for high-performance diagnosis and/or therapy of various diseases. However, dynamic nano-bio interaction between DNDDS and biological systems remains poorly understood, which can be critical for precise spatiotemporal and functional control of DNDDS in vivo. To deepen the understanding for fine control over DNDDS, we aim to explore natural systems as the root of inspiration for researchers from various fields. This review highlights ingenious designs, nano-bio interactions, and controllable functionalities of state-of-the-art DNDDS under endogenous or exogenous stimuli, by learning from nature at the molecular, subcellular, and cellular levels. Furthermore, the assembly strategies and response mechanisms of tailor-made DNDDS based on the characteristics of various diseased microenvironments are intensively discussed. Finally, the current challenges and future perspectives of DNDDS are briefly commented.

A High-Resolution Ternary Model Demonstrates How PEGylated 2D Nanomaterial Stimulates Integrin αv β8 on Cell Membrane

Bio-nano interfaces are integral to all applications of nanomaterials in biomedicine. In addition to peptide-ligand-functionalized nanomaterials, passivation on 2D nanomaterials has emerged as a new regulatory factor for integrin activation. However, the mechanisms underlying such ligand-independent processes are poorly understood. Here, using graphene oxide passivated with polyethylene glycol (GO-PEG) as a test bed, a ternary simulation model is constructed that also includes a membrane and both subunits of integrin αv β8 to characterize GO-PEG-mediated integrin activation on the cell membrane in a ligand-independent manner. Combined with the experimental findings, production simulations of the ternary model show a three-phase mechanotransduction process in the vertical interaction mode. Specifically, GO-PEG first induces lipid aggregation-mediated integrin proximity, followed by transmembrane domain rotation and separation, leading to the extension and activation of extracellular domains. Thus, this study presents a complete picture of the interaction between passivated 2D nanomaterials and cell membranes to mediate integrin activation, and provides insights into the potential de novo design and rational use of novel desirable nanomaterials at diverse bio-nano interfaces.

Magnetic Nanostructures as Emerging Therapeutic Tools to Boost Anti-Tumour Immunity

Cancer immunotherapy has shown remarkable results in various cancer types through a range of immunotherapeutic approaches, including chimeric antigen receptor-T cell (CAR-T) therapy, immune checkpoint blockade (ICB), and therapeutic vaccines. Despite the enormous potential of cancer immunotherapy, its application in various clinical settings has been limited by immune evasion and immune suppressive mechanisms occurring locally or systemically, low durable response rates, and severe side effects. In the last decades, the rapid advancement of nanotechnology has been aiming at the development of novel synthetic nanocarriers enabling precise and enhanced delivery of immunotherapeutics, while improving drug stability and effectiveness. Magnetic nanostructured formulations are particularly intriguing because of their easy surface functionalization, low cost, and robust manufacturing procedures, together with their suitability for the implementation of magnetically-guided and heat-based therapeutic strategies. Here, we summarize and discuss the unique features of magnetic-based nanostructures, which can be opportunely designed to potentiate classic immunotherapies, such as therapeutic vaccines, ICB, adoptive cell therapy (ACT), and in situ vaccination. Finally, we focus on how multifunctional magnetic delivery systems can facilitate the anti-tumour therapies relying on multiple immunotherapies and/or other therapeutic modalities. Combinatorial magnetic-based therapies are indeed offering the possibility to overcome current challenges in cancer immunotherapy.

Orchestration of biomimetic membrane coating and nanotherapeutics in personalized anticancer therapy

Nanoparticle-based therapeutic and detectable modalities can augment anticancer efficiency, holding potential in capable target and suppressive metastases post administration. However, the individual discrepancies of the current "one-size-fits-all" strategies for anticancer nanotherapeutics have heralded the need for "personalized therapy". Benefiting from the special inherency of various cells, diverse cell membrane-coated nanoparticles (CMCNs) were established on a patient-by-patient basis, which would facilitate the personalized treatment of individual cancer patients. CMCNs in a complex microenvironment can evade the immune system and target homologous tumors with a suppressed immune response, as well as a prolonged circulation time, consequently increasing the drug accumulation at the tumor site and anticancer therapeutic efficacy. This review focuses on the emerging strategies and advances of CMCNs to synergistically integrate the merit of source cells with nanoparticulate delivery systems for the orchestration of personalized anticancer nanotherapeutics, thus discussing their rationalities in facilitating chemotherapy, imaging, immunotherapy, phototherapy, radiotherapy, sonodynamic, magnetocaloric, chemodynamic and gene therapy. Furthermore, the mechanism, challenges and opportunities of CMCNs in personalized anticancer therapy were highlighted to further boost cooperation from different fields, including materials science, chemistry, medicine, pharmacy and biology for the lab-to-clinic translation of CMCNs combined with the individual advantages of source cells and nanotherapeutics.

Delivery of nanoparticle antigens to antigen-presenting cells: from extracellular specific targeting to intracellular responsive presentation

An appropriate delivery system can improve the immune effects of antigens against various infections or tumors. Antigen-presenting cells (APCs) are specialized to capture and process antigens in vivo, which link the innate and adaptive immune responses. Functionalization of vaccine delivery systems with targeting moieties to APCs is a promising strategy for provoking potent immune responses. Additionally, the internalization and intracellular distribution of antigens are closely related to the initiation of downstream immune responses. With a deeper understanding of the intracellular microenvironment and the mechanisms of antigen presentation, vehicles designed to respond to endogenous and external stimuli can modulate antigen processing and presentation pathways, which are critical to the types of immune response. Here, an overview of extracellular targeting delivery of antigens to APCs and intracellular stimulus-responsiveness strategies is provided, which might be helpful for the rational design of vaccine delivery systems.

Activable Multi-Modal Nanoprobes for Imaging Diagnosis and Therapy of Tumors

Malignant tumors have become one of the major causes of human death, but there remains a lack of effective methods for tiny tumor diagnosis, metastasis warning, clinical efficacy prediction, and effective treatment. In this context, localizing tiny tumors via imaging and non-invasively extracting molecular information related to tumor proliferation, invasion, metastasis, and drug resistance from the tumor microenvironment have become the most fundamental tasks faced by cancer researchers. Tumor-associated microenvironmental physiological parameters, such as hypoxia, acidic extracellular pH, protease, reducing conditions, and so forth, have much to do with prognostic indicators for cancer progression, and impact therapeutic administrations. By combining with various novel nanoparticle-based activatable probes, molecular imaging technologies can provide a feasible approach to visualize tumor-associated microenvironment parameters noninvasively and realize accurate treatment of tumors. This review focuses on the recent achievements in the design of “smart” nanomedicine responding to the tumor microenvironment-related features and highlights state-of- the-art technology in tumor imaging diagnosis and therapy.

Hyaluronate-Based Self-Stabilized Nanoparticles for Immunosuppression Reversion and Immunochemotherapy in Osteosarcoma Treatment

Immunotherapy is regarded as a potential strategy to combat cancer, especially when immunotherapy is combined with appropriate chemotherapy. However, the immunosuppressive tumor microenvironment (TME) and serious side effects extremely limit the application of immunotherapy. Herein, a self-stabilized hyaluronic acid nanoparticle is synthesized for tumor-targeted delivery of doxorubicin (DOX), cisplatin (CDDP), and resiquimod (R848) in osteosarcoma immunochemotherapy, which is referred to as ^CDDPNP_DOX&R848. ^CDDPNP_DOX&R848 exhibits sufficient stability, great pH responsibility, and brilliant tumor-targeting accumulation in vivo, which make it suitable for further in vivo applications. After intravenous injection, ^CDDPNP_DOX&R848 can release the loaded cargoes under the acidic TME continuously. DOX can induce tumor cell apoptosis in combination with CDDP and trigger immunogenic cell death. More importantly, the immune-activated TME created by R848 can facilitate tumor-associated antigen presentation and antitumor immunity elicitation. Benefiting from the synergistic effect of chemotherapy and immunotherapy, the growth of tumors and lung metastasis was greatly inhibited by ^CDDPNP_DOX&R848 in the K7M2 orthotopic osteosarcoma mouse model. Thus, this intelligent codelivery platform might be a competitive candidate for osteosarcoma immunochemotherapy.

Engineering Prodrug Nanomedicine for Cancer Immunotherapy

Immunotherapy has shifted the clinical paradigm of cancer management. However, despite promising initial progress, immunotherapeutic approaches to cancer still suffer from relatively low response rates and the possibility of severe side effects, likely due to the low inherent immunogenicity of tumor cells, the immunosuppressive tumor microenvironment, and significant inter- and intratumoral heterogeneity. Recently, nanoformulations of prodrugs have been explored as a means to enhance cancer immunotherapy by simultaneously eliciting antitumor immune responses and reversing local immunosuppression. Prodrug nanomedicines, which integrate engineering advances in chemistry, oncoimmunology, and material science, are rationally designed through chemically modifying small molecule drugs, peptides, or antibodies to yield increased bioavailability and spatiotemporal control of drug release and activation at the target sites. Such strategies can help reduce adverse effects and enable codelivery of multiple immune modulators to yield synergistic cancer immunotherapy. In this review article, recent advances and translational challenges facing prodrug nanomedicines for cancer immunotherapy are overviewed. Last, key considerations are outlined for future efforts to advance prodrug nanomedicines aimed to improve antitumor immune responses and combat immune tolerogenic microenvironments.

Synthetic Particles for Cancer Vaccines: Connecting the Inherent Supply Chain

Cancer vaccines have opened a new paradigm for safe and effective antitumor therapy, but they still suffer from shortcomings such as insufficient immunogenicity and immune tolerance, which seldom makes them the first choice in clinic. In fact, similar to providing a high-end product, a robust antitumor effect depends on the inherent supply chain, which attains, processes, and presents tumor-associated antigens via antigen presenting cells to T cells, which then leads to lysis of the cancer cells to release more antigens to complete the supply chain. Under these circumstances, the failure of cancer vaccines can be treated as a blockade or chain rupture. Thus, for effective tumor treatment, the key is to rationally design logistic systems to restore the supply chain.Under these circumstances, this Account summarizes our recent attempts to exploit the immunogenic trait of synthetic particles to enhance the distribution, presentation, and immune activations of the whole priming process in cancer vaccines: (1) Raw material (tumor antigen/signals) procurement: We illustrated the efforts to deliver antigens to antigen presenting cells (APCs) and draining lymph nodes for potent internalizations, and put more emphasis on the structural effect of sizes, charges, shapes, and assembly strategies for the antigen depot, lymph node transfer, and APC endocytosis. (2) Manufacture of cytotoxic T lymphocytes (CTLs) via APC recognition and presentation: We centered on exploiting the softness of two-dimensional graphene and Pickering emulsions to dynamically potentiate the immune recognition, and demonstrating the recent advances in lysosome escape strategies for enhanced antigen cross-presentations. (3) Marketing the accumulations of CTLs and the reversal of an immunosuppressive microenvironment within the tumor: We demonstrated the previous attempts to inherently cultivate the tumor tropism of the T cells via the multiantigenic repertoire and discussed the advances and challenges of combinatory cancer vaccines with an immune checkpoint blockade to reinforce the antitumor efficacy. Collectively, this Account aims to illustrate the potential of the particulate cancer vaccines to recapitalize the inherent host immune responses for the maximum antitumor effect. And by integrating the antitumor supply chain, optimized synthetic particles may shed light on the development of safe and effective particulate cancer vaccines.

Choice of Nanovaccine Delivery Mode Has Profound Impacts on the Intralymph Node Spatiotemporal Distribution and Immunotherapy Efficacy

Nanovaccines have attracted booming interests in vaccinology studies, but the profound impacts of their delivery mode on immune response remain unrealized. Herein, immunostimulatory CpG-modified tumor-derived nanovesicles (CNVs) are used as a nanovaccine testbed to initially evaluate the impacts of three distinct delivery modes, including mono-pulse CNVs, staggered-pulse CNVs, and gel-confined CNVs. Fundamentally, delivery mode has enormous impacts on the immunomodulatory effects, altering the spatiotemporal distribution of nanovaccine residence and dendritic cell-T cell interaction in lymph nodes, and finally affecting subsequent T cell-mediated immune performance. As a result, the gel-confined delivery mode offers the best therapeutic performance in multiple tumor models. When extending evaluation to examine how the various delivery modes impact the performance of liposome-based nanovaccines, similar trends in intralymph node distribution and antitumor effect are observed. This work provides a strong empirical foundation that nanovaccine researchers should position delivery mode near the top of their considerations for the experimental design, which should speed up nanovaccine development and facilitate efficient selection of appropriate delivery modes in the clinic.

Stimuli-Responsive Biomaterials for Vaccines and Immunotherapeutic Applications

The immune system is the key target for vaccines and immunotherapeutic approaches aimed at blunting infectious diseases, cancer, autoimmunity, and implant rejection. However, systemwide immunomodulation is undesirable due to the severe side effects that typically accompany such strategies. In order to circumvent these undesired, harmful effects, scientists have turned to tailorable biomaterials that can achieve localized, potent release of immune-modulating agents. Specifically, "stimuli-responsive" biomaterials hold a strong promise for delivery of immunotherapeutic agents to the disease site or disease-relevant tissues with high spatial and temporal accuracy. This review provides an overview of stimuli-responsive biomaterials used for targeted immunomodulation. Stimuli-responsive or "environmentally responsive" materials are customized to specifically react to changes in pH, temperature, enzymes, redox environment, photo-stimulation, molecule-binding, magnetic fields, ultrasound-stimulation, and electric fields. Moreover, the latest generation of this class of materials incorporates elements that allow for response to multiple stimuli. These developments, and other stimuli-responsive materials that are on the horizon, are discussed in the context of controlling immune responses.

Cell and tissue engineering in lymph nodes for cancer immunotherapy

In cancer, lymph nodes (LNs) coordinate tumor antigen presentation necessary for effective antitumor immunity, both at the levels of local cellular interactions and tissue-level organization. In this review, we examine how LNs may be engineered to improve the therapeutic outcomes of cancer immunotherapy. At the cellular scale, targeting the LNs impacts the potency of cancer vaccines, immune checkpoint blockade, and adoptive cell transfer. On a tissue level, macro-scale biomaterials mimicking LN features can function as immune niches for cell reprogramming or delivery in vivo, or be utilized in vitro to enable preclinical testing of drugs and vaccines. We additionally review strategies to induce ectopic lymphoid sites reminiscent of LNs that may improve antitumor T cell priming.