Scaffolds that mimic antigen-presenting cells enable ex vivo expansion of primary T cells

Immunomodulatory bioadhesive technologies

Bioadhesives have found significant use in medicine and engineering, particularly for wound care, tissue engineering, and surgical applications. Compared to traditional wound closure methods such as sutures and staples, bioadhesives offer advantages, including reduced tissue damage, enhanced healing, and ease of implementation. Recent progress highlights the synergy of bioadhesives and immunoengineering strategies, leading to immunomodulatory bioadhesives capable of modulating immune responses at local sites where bioadhesives are applied. They foster favorable therapeutic outcomes such as reduced inflammation in wounds and implants or enhanced local immune responses to improve cancer therapy efficacy. The dual functionalities of bioadhesion and immunomodulation benefit wound management, tissue regeneration, implantable medical devices, and post-surgical cancer management. This review delves into the interplay between bioadhesion and immunomodulation, highlighting the mechanobiological coupling involved. Key areas of focus include the modulation of immune responses through chemical and physical strategies, as well as the application of these bioadhesives in wound healing and cancer treatment. Discussed are remaining challenges such as achieving long-term stability and effectiveness, necessitating further research to fully harness the clinical potential of immunomodulatory bioadhesives.

Melting point matters: designing lipid nanocarriers for improved T cell activation

Surface-modified lipid nanocarriers are increasingly used as artificial antigen-presenting cells for therapeutic applications in immunotherapy. Within these nanocarriers, the role of the lipids is typically limited to providing structure/stability of the particle, to anchoring a targeting moiety, and/or to altering the biodistribution of the nanocarriers in vivo. However, lipid membranes also possess special thermodynamic properties that impact their function. Here, we investigate the effect of the melting transition temperature of lipid nanocarriers on the activation efficiency of an immortalized line of T lymphocytes. Using an established in vitro activation assay and αCD3-functionalized lipid nanocarriers, we screened a variety of lipid nanocarriers with respect to their capacity to activate T cells. We observed a correlation between T cell activation efficiency and proximity of the melting transition temperature of the lipid nanocarrier to the temperature at which the activation study was conducted (37 °C). This relationship held across a variety of lipid compositions and appeared to be more important than the lipid headgroup or chain length. This trend was preserved when the activation temperature was shifted to 30 °C, supporting the role of the nanocarrier membrane state for target cell activation and the potential impact of phase-transition-related effects on nanocarrier activity. We conclude that lipid composition is indeed an important parameter for lipid-based nanocarrier design, not only for the more explored biochemical roles of the lipids but also for the thermodynamic properties the lipid mixtures generate. Our results provide a new consideration in therapeutic nanocarrier design that could significantly improve the efficacy of targeted nanocarrier formulations.

Cell-Instructive Biomaterials with Native-Like Biochemical Complexity

Biochemical signals in native tissue microenvironments instruct cell behavior during many biological processes ranging from developmental morphogenesis and tissue regeneration to tumor metastasis and disease progression. The detection and characterization of these signals using spatial and highly resolved quantitative methods have revealed their existence as matricellular proteins in the matrisome, some of which are bound to the extracellular matrix while others are freely diffusing. Including these biochemical signals in engineered biomaterials can impart enhanced functionality and native-like complexity, ultimately benefiting efforts to understand, model, and treat various diseases. In this review, we discuss advances in characterizing, mimicking, and harnessing biochemical signals in developing advanced engineered biomaterials. An overview of the diverse forms in which these biochemical signals exist and their effects on intracellular signal transduction is also provided. Finally, we highlight the application of biochemically complex biomaterials in the three broadly defined areas of tissue regeneration, immunoengineering, and organoid morphogenesis.

Mechanoregulation of lymphocyte cytotoxicity

Cytotoxic lymphocytes counter intracellular pathogens and cancer by recognizing and destroying infected or transformed target cells. The basis for their function is the cytolytic immune synapse, a structurally stereotyped cell-cell interface through which lymphocytes deliver toxic proteins to target cells. The immune synapse is a highly dynamic contact capable of exerting nanonewton-scale forces against the target cell. In recent years, it has become clear that the interplay between these forces and the biophysical properties of the target influences the entirety of the cytotoxic response, from the initial activation of cytotoxic lymphocytes to the release of dying target cells. As a result, cellular cytotoxicity has become an exemplar of the ways in which biomechanics can regulate immune cell activation and effector function. This Review covers recent progress in this area, which has prompted a reconsideration of target cell killing from a more mechanobiological perspective.

Silicasomes in Oncology: From Conventional Chemotherapy to Combined Immunotherapy

The use of nanoparticles as drug carriers in oncology has evolved from their traditional role as chemotherapy carriers to their application in immunotherapy, exploiting not only their passive accumulation in solid tumors but also their ability to interact with immune cells. Silicasomes are highly versatile nanoplatforms composed of a mesoporous silica core whose external surface is coated with a lipid bilayer that allows the co-delivery of therapeutic agents having different chemical natures (small molecules, proteins, enzymes, or oligonucleotides, among others). Herein, cutting-edge advances carried out in the development and application of silicasomes are presented, providing a general description of the performance of these nanotransporters. Additionally, the specific load of chemotherapeutic drugs is explored, followed by a discussion of the immunotherapeutic application of silicasomes and the combination of different therapeutic strategies, including theragnosis, in a single silicasome platform, highlighting the enormous potential of these nanosystems.

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.

Cytoskeleton-functionalized synthetic cells with life-like mechanical features and regulated membrane dynamicity

The cytoskeleton is a crucial determinant of mammalian cell structure and function, providing mechanical resilience, supporting the cell membrane and orchestrating essential processes such as cell division and motility. Because of its fundamental role in living cells, developing a reconstituted or artificial cytoskeleton is of major interest. Here we present an approach to construct an artificial cytoskeleton that imparts mechanical support and regulates membrane dynamics. Our system involves amylose-based coacervates stabilized by a terpolymer membrane, with a cytoskeleton formed from polydiacetylene fibrils. The fibrils bundle due to interactions with the positively charged amylose derivative, forming micrometre-sized structures mimicking a cytoskeleton. Given the intricate interplay between cellular structure and function, the design and integration of this artificial cytoskeleton represent a crucial advancement, paving the way for the development of artificial cell platforms exhibiting enhanced life-like behaviour.

Controlled activation modulates T-cell expansion and phenotype in stirred-tank bioreactors

BACKGROUND AIMS

Autologous cell therapies using chimeric antigen receptor (CAR) T cells have shown significant clinical success in hematologic cancers. However, current production platforms face challenges in scaling up to produce sufficient numbers of cells to meet the demands of multi-dose regimens. Additionally, tight control over critical process parameters during the distinct stages of cell production is required to maximize key phenotypic characteristics of CAR T-cell products that correlate with improved clinical responses. To address these issues, we propose an integrated manufacturing process in stirred-tank bioreactors (STBs) for controlled T-cell activation and expansion.

METHODS

By tailoring the stirring profile of STBs (Ambr 15 bioreactors; Sartorius, Göttingen, Germany), microbeads functionalized with anti-CD3/CD28 antibodies allow control over the initiation/termination of T-cell activation without requiring additional washing steps to remove the activation signaling cues.

RESULTS

This strategy resulted in up to a 10-fold increase in T-cell numbers compared with conventional static culture systems, resulting in a final cell concentration of 2.5 × 107 cells/mL after 10 days of culture. Importantly, a higher proportion of CD8+ T cells and lower expression of exhaustion markers programmed cell death protein 1, lymphocyte activation gene 3 and T-cell immunoglobulin and mucin domain 3 (<8%) were obtained in STBs relative to static cultures. Additionally, the anti-CD3/CD28-functionalized microbeads were as efficient as the standard TransAct (Miltenyi Biotec, Bergisch Gladbach, Germany) stimuli in activating and expanding T cells in STBs.

CONCLUSIONS

Overall, this approach presents a promising strategy for the scalable and tightly controlled manufacturing of T-cell therapies, particularly focusing on the T-cell activation step while minimizing manual operations, thus contributing to more and cost-effective immunotherapies.

Subcutaneous biodegradable scaffolds for restimulating the antitumour activity of pre-administered CAR-T cells

The efficacy of adoptive T-cell therapies based on chimaeric antigen receptors (CARs) is limited by the poor proliferation and persistence of the engineered T cells. Here we show that a subcutaneously injected biodegradable scaffold that facilitates the infiltration and egress of specific T-cell subpopulations, which forms a microenvironment mimicking features of physiological T-cell activation, enhances the antitumour activity of pre-administered CAR-T cells. CAR-T-cell expansion, differentiation and cytotoxicity were driven by the scaffold's incorporation of co-stimulatory bound ligands and soluble molecules, and depended on the types of co-stimulatory molecules and the context in which they were presented. In mice with aggressive lymphoma, a single, local injection of the scaffold following non-curative CAR-T-cell dosing led to more persistent memory-like T cells and extended animal survival. Injectable biomaterials with optimized ligand presentation may boost the therapeutic performance of CAR-T-cell therapies.

Heart-on-a-chip: a revolutionary organ-on-chip platform for cardiovascular disease modeling

Heart-on-a-chip (HoC) devices have emerged as a powerful tool for studying the human heart's intricate functions and dysfunctions in vitro. Traditional preclinical models, such as 2D cell cultures model and animal model, have limitations in accurately predicting human response to cardiovascular diseases and treatments. The HoC approach addresses these shortcomings by recapitulating the microscale anatomy, physiology, and biomechanics of the heart, thereby providing a more clinically relevant platform for drug testing, disease modeling, and personalized therapy. Recent years have seen significant strides in HoC technology, driven by advancements in biomaterials, bioelectronics, and tissue engineering. Here, we first review the construction and on-chip detection in HoC. Then we introduce the current proceedings of in vitro models for studying cardiovascular diseases (CVD) based on the HoC platform, including ischemia and myocardial infarction, cardiac fibrosis, cardiac scar, myocardial hypertrophy and other CVD models. Finally, we discuss the future directions of HoC and related emerging technologies.

Mannose metabolism reshapes T cell differentiation to enhance anti-tumor immunity

Cellular metabolic status profoundly influences T cell differentiation, persistence, and anti-tumor efficacy. Our single-cell metabolic analyses of T cells reveal that diminished mannose metabolism is a prominent feature of T cell dysfunction. Conversely, experimental augmentation/restoration of mannose metabolism in adoptively transferred T cells via D-mannose supplementation enhances anti-tumor activity and restricts exhaustion differentiation both in vitro and in vivo. Mechanistically, D-mannose treatment induces intracellular metabolic programming and increases the O-GlcNAc transferase (OGT)-mediated O-GlcNAcylation of β-catenin, which preserves Tcf7 expression and epigenetic stemness, thereby promoting stem-like programs in T cells. Furthermore, in vitro expansion with D-mannose supplementation yields T cell products for adoptive therapy with stemness characteristics, even after extensive long-term expansion, that exhibits enhanced anti-tumor efficacy. These findings reveal cell-intrinsic mannose metabolism as a physiological regulator of CD8+ T cell fate, decoupling proliferation/expansion from differentiation, and underscoring the therapeutic potential of mannose modulation in cancer immunotherapy.

Ex vivo enhancement of CD8+ T cell activity using functionalized hydrogel encapsulating tonsil-derived lymphatic endothelial cells

Rationale: This study investigates a method for programming immune cells using a biomaterial-based system, providing an alternative to traditional ex vivo cell manipulation techniques. It addresses the limitations of engineered adoptive T cell therapies, such as T cell exhaustion, by introducing a gelatin-hyaluronic acid (GH-GMA) hydrogel system. Methods: We characterized tonsil mesenchymal stem cells (TMSCs), lymphatic endothelial cells (T-LECs), stimulated T-CD8+ T cells (STCs), and GH-GMA biomaterials. The 10% 5:1 GH-GMA hydrogel, loaded with anti-CD28, cytokines interleukin-2 (IL-2) and vascular endothelial growth factor C (VEGF-C), forms a functional hydrogel capable of releasing these immune-stimulating factors. T-LEC spheroids, derived from tonsil mesenchymal stem cells (TMSCs), were encapsulated within the hydrogel to act as antigen-presenting cells for T cells. Results: Co-encapsulation of STCs and T-LEC spheroids in the functional hydrogel resulted in significant expansion and enrichment of STCs during cultivation. Moreover, when cancer cells were co-encapsulated with STCs and T-LECs, there was increased migration of STCs towards the cancer cells and elevated expression of PD-L1 on the cancer cells. Conclusions: These findings suggest that the GH-GMA hydrogel, combined with anti-CD28, IL-2, VEGF-C, and T-LEC spheroids, enhances T cell activity, presenting a promising platform for cancer immunotherapies and modulation of the suppressive tumor microenvironment.

Viscoelastic synthetic antigen-presenting cells for augmenting the potency of cancer therapies

The use of synthetic antigen-presenting cells to activate and expand engineered T cells for the treatment of cancers typically results in therapies that are suboptimal in effectiveness and durability. Here we describe a high-throughput microfluidic system for the fabrication of synthetic cells mimicking the viscoelastic and T-cell-activation properties of antigen-presenting cells. Compared with rigid or elastic microspheres, the synthetic viscoelastic T-cell-activating cells (SynVACs) led to substantial enhancements in the expansion of human CD8+ T cells and to the suppression of the formation of regulatory T cells. Notably, activating and expanding chimaeric antigen receptor (CAR) T cells with SynVACs led to a CAR-transduction efficiency of approximately 90% and to substantial increases in T memory stem cells. The engineered CAR T cells eliminated tumour cells in a mouse model of human lymphoma, suppressed tumour growth in mice with human ovarian cancer xenografts, persisted for longer periods and reduced tumour-recurrence risk. Our findings underscore the crucial roles of viscoelasticity in T-cell engineering and highlight the utility of SynVACs in cancer therapy.

Biomimetic cell stimulation with a graphene oxide antigen-presenting platform for developing T cell-based therapies

Chimeric antigen receptor (CAR)-engineered T cells represent a front-line therapy for cancers. However, the current CAR T cell manufacturing protocols do not adequately reproduce immunological synapse formation. Here, in response to this limitation, we have developed a flexible graphene oxide antigen-presenting platform (GO-APP) that anchors antibodies onto graphene oxide. By decorating anti-CD3 (αCD3) and anti-CD28 (αCD28) on graphene oxide (GO-APP3/28), we achieved remarkable T cell proliferation. In vitro interactions between GO-APP3/28 and T cells closely mimic the in vivo immunological synapses between antigen-presenting cells and T cells. This immunological synapse mimicry shows a high capacity for stimulating T cell proliferation while preserving their multifunctionality and high potency. Meanwhile, it enhances CAR gene-engineering efficiency, yielding a more than fivefold increase in CAR T cell production compared with the standard protocol. Notably, GO-APP3/28 stimulated appropriate autocrine interleukin-2 (IL-2) in T cells and overcame the in vitro reliance on external IL-2 supplementation, offering an opportunity to culture T cell-based products independent of IL-2 supplementation.

Liquid Phase Exfoliation of Protein Parent Crystals into Nanosheets and Fibrils Based on Orthogonal Supramolecular Interactions

Proteins are attractive building blocks for fabricating diverse and precise nanomaterials. However, the facile fabrication of multidimensional artificial assemblies is highly challenging. Here, inspired by the large-scale production technique of inorganic nanomaterials, we demonstrate the application of liquid phase exfoliation (LPE) on native protein ConA by the design of synthetic ligands. These ligands provide distinct in-plane and out-of-plane supramolecular interactions, allowing the generation of multidimensional architectures based on the same protein by dissociating a single interaction in solution, including 3D porous protein crystals, 2D sizable nanosheets, and 1D fibrils. Importantly, the exfoliated 2D sheets were dozens of times larger than the self-assembled nanosheets, resulting in a dramatic enhancement of the intrinsic bioactivity of the building blocks by receptor clustering and less endocytosis. These findings enable the successful application of LPE on biomacromolecules and open up an alternative avenue to generate advanced multidimensional nanomaterials, without the need for complex protein design and careful adjustment of self-assembly conditions.

Replenishing Cation-π Interactions for the Fabrication of Mesoporous Levodopa Nanoformulations for Parkinson Remission

Directly assembling drugs into mesoporous nanoformulations will be greatly favored due to the combination of enhanced drug delivery efficiency and mesostructure-enabled nanobio interactions. However, such an approach is hindered due to the lack of understanding of polymer nanoparticles' formation mechanism, especially the relationship between polymerization, self-assembly, and the nucleation process. Here, by investigating the levodopa and dopamine polymerization process, we identify π-cation interaction as pivotal in the self-assembly and nucleation control of dopa molecules. Thus, through manipulation of the π-cation interaction, we present the direct assembly of a commercial drug, levodopa, into mesoporous nanoformulations. The synthesized nanospheres, approximately 200 nm in diameter, exhibit uniform mesopores of around 8 nm. These nanoformulations, abundant in mesopores, enhance chiral phenylalanine interaction with α-synuclein (Syn), curbing aggregation, safeguarding neurons, and alleviating Parkinson's pathology. When combating α-synuclein, the nanoformulation achieved ∼100% inhibition of protein aggregation and sustained neuron viability up to 300%. We believe that this study may advance mesoscale self-assembly knowledge, guiding future nanopharmaceutical developments.

In vivo human T cell engineering with enveloped delivery vehicles

Viruses and virally derived particles have the intrinsic capacity to deliver molecules to cells, but the difficulty of readily altering cell-type selectivity has hindered their use for therapeutic delivery. Here, we show that cell surface marker recognition by antibody fragments displayed on membrane-derived particles encapsulating CRISPR-Cas9 protein and guide RNA can deliver genome editing tools to specific cells. Compared to conventional vectors like adeno-associated virus that rely on evolved capsid tropisms to deliver virally encoded cargo, these Cas9-packaging enveloped delivery vehicles (Cas9-EDVs) leverage predictable antibody-antigen interactions to transiently deliver genome editing machinery selectively to cells of interest. Antibody-targeted Cas9-EDVs preferentially confer genome editing in cognate target cells over bystander cells in mixed populations, both ex vivo and in vivo. By using multiplexed targeting molecules to direct delivery to human T cells, Cas9-EDVs enable the generation of genome-edited chimeric antigen receptor T cells in humanized mice, establishing a programmable delivery modality with the potential for widespread therapeutic utility.

Adaptive immunity of materials: Implications for tissue healing and regeneration

Recent cumulative findings signify the adaptive immunity of materials as a key agenda in tissue healing that can improve regenerative events and outcomes. Modulating immune responses, mainly the recruitment and functions of T and B cells and their further interplay with innate immune cells (e.g., dendritic cells, macrophages) can be orchestrated by materials. For instance, decellularized matrices have been shown to promote muscle healing by inducing T helper 2 (Th2) cell immunity, while synthetic biopolymers exhibit differential effects on B cell responses and fibrosis compared decellularized matrices. We discuss the recent findings on how implantable materials instruct the adaptive immune events and the subsequent tissue healing process. In particular, we dissect the materials' physicochemical properties (shape, size, topology, degradation, rigidity, and matrix dynamic mechanics) to demonstrate the relations of these parameters with the adaptive immune responses in vitro and the underlying biological mechanisms. Furthermore, we present evidence of recent in vivo phenomena, including tissue healing, cancer progression, and fibrosis, wherein biomaterials potentially shape adaptive immune cell functions and in vivo outcomes. Our discussion will help understand the materials-regulated immunology events more deeply, and offer the design rationale of materials with tunable matrix properties for accelerated tissue repair and regeneration.

Artificial antigen-presenting cell system reveals CD28's role in modulating T cell functions during human immunodeficiency virus infection

T cell immune dysfunction is a prominent feature of chronic HIV infection. To evaluate non-specific dysfunction, a method involving both generic activation and T cell receptor (TCR) stimulation is necessary. We created a tunable artificial antigen-presenting cell (aAPC) system. This system consists of lipid bilayers on cytometry-compatible silica microbeads (5 μm). When only anti-CD3 is incorporated, T cell activation is limited. Introducing anti-CD28 agonists significantly elevates the cytokine expression and upregulation of activation-induced markers. CD28 co-stimulation modulates the response profile, preferentially promoting IL-2 expression relative to other cytokines. aAPCs-stimulated CD4+ and CD8+ T cells from untreated HIV-infected individuals exhibit altered effector functions and diminished CD28 dependence. These functions are skewed toward TNFα, IFNγ and CD107a, with reduced IL-2. Antiretroviral therapy partially normalizes this distorted profile in CD4+ T cells, but not in CD8+ T cells. Our findings show T cell intrinsic biases that may contribute to persistent systemic T cell dysfunction associated with HIV pathogenesis.

Jump-starting chimeric antigen receptor-T cells to go the extra mile with nanotechnology

Despite success in treating hematologic malignancies, chimeric antigen receptor-T cell (CAR-T) therapy still faces multiple challenges that have halted progress, especially against solid tumors. Recent advances in nanoscale engineeirng provide several avenues for overcoming these challenges, including more efficienct programming of CAR-Ts ex vivo, promoting immune responsiveness in the tumor microenvironment (TME) in vivo, and boosting CAR-T function in situ. Here, we summarize recent innovations that leverage nanotechnology to directly address the major obstacles that impede CAR-T therapy from reaching its full potential across various cancer types. We conclude with a commentary on the state of the field and how nanotechnology can shape the future of CAR-T and adoptive cell therapy in immuno-oncology.

Engineering Functional Particles to Modulate T Cell Responses

T cells play a critical role in adaptive immune responses. They work with other immune cells such as B cells to protect our bodies when the first line of defense, the innate immune system, is overcome by certain infectious diseases or cancers. Studying and regulating the responses of T cells, such as activation, proliferation, and differentiation, helps us understand not only their behavior in vivo but also their translation and application in the field of immunotherapy, such as adoptive T cell therapy and immune checkpoint therapy, the situations in which T cells cannot fight cancer alone and require external engineering regulation to help them. Nano- to micrometer-sized particulate biomaterials have achieved great progress in the assistance of T cell-based immunomodulation. For example, various types of microparticles decorated with T cell recognition and activation signals to mimic native antigen-presenting cells have shown successful ex vivo expansion of primary T cells and have been approved for clinical use in adoptive T cell therapy. Functional particles can also serve as vehicles for transporting cargos including small molecule drugs, cytokines, and antibodies. Especially for cargos with limited bioavailability and high repeat-dose toxicity, systemic administration in their free form is difficult. By using particle-assisted systems, the delivery can be tailored on demand, of which targeting and controlled release are two typical examples, ultimately aiding in the regulation of T cell responses. Furthermore, when T cells become overactive and behave in ways that contradict our expectations, such as attacking our own cells or innocuous foreign molecules, this can lead to a breakdown of immune tolerance. In such cases, particles to help reprogram those overactive T cells or suppress their activity are appreciated in vivo. The urgent need to introduce immune stimulation into the treatment of cancers, infectious diseases, and autoimmune diseases has driven recent advances in the engineering of functional particulate biomaterials that regulate T cell responses. In this Account, we will first cover a brief overview of the process of T cell-based immunomodulation from principle to development. It then outlines critical points in the design of functional particle platforms, including materials, size, morphology, surface engineering, and delivery of cargos, to modulate the features of T cells, and introduces selected work from our and other research groups with a focus on three major therapeutic applications: adoptive T cell therapy, immune checkpoint therapy, and immune tolerance restoration. Current challenges and future opportunities are also discussed.

A general pHLA-CD80 scaffold fusion protein to promote efficient antigen-specific T cell-based immunotherapy

Inadequate antigen-specific T cells activation hampers immunotherapy due to complex antigen presentation. In addition, therapeutic in vivo T cell expansion is constrained by slow expansion rates and limited functionality. Herein, we introduce a model fusion protein termed antigen-presenting cell-mimic fusion protein (APC-mimic), designed to greatly mimicking the natural antigen presentation pattern of antigen-presenting cells and directly expand T cells both in vitro and in vivo. The APC-mimic comprises the cognate peptide-human leukocyte antigen (pHLA) complex and the co-stimulatory marker CD80, which are natural ligands on APCs. Following a single stimulation, APC-mimic leads to an approximately 400-fold increase in the polyclonal expansion of antigen-specific T cells compared with the untreated group in vitro without the requirement for specialized antigen-presenting cells. Through the combination of single-cell TCR sequencing (scTCR-seq) and single-cell RNA sequencing (scRNA-seq), we identify an approximately 600-fold monoclonal expansion clonotype among these polyclonal clonotypes. It also exhibits suitability for in vivo applications confirmed in the OT-1 mouse model. Furthermore, T cells expanded by APC-mimic effectively inhibits tumor growth in adoptive cell transfer (ACT) murine models. These findings pave the way for the versatile APC-mimic platform for personalized therapeutics, enabling direct expansion of polyfunctional antigen-specific T cell subsets in vitro and in vivo.

Application of fibrin-based biomaterial for human ovarian tissue encapsulation and cryopreservation as alternative approach for fertility preservation

This study aimed to investigate the effects of fibrin-based hydrogel encapsulation, with or without vascular endothelial growth factor (VEGF), on follicle quality and cell survival signaling pathways after ovarian tissue cryopreservation. Ovarian cortex donated by seven patients (ages 44-47 years old) was divided into four groups: I) fresh control, II) ovarian tissue without encapsulation (non-FT), III) fibrin (10 mg/mL fibrinogen plus 50 IU/mL thrombin; 10FT) encapsulated tissue without VEGF, and IV) encapsulated tissue with 0.1 μg/mL VEGF (10FT-VEGF), followed by a slow freezing process. Evaluation criteria included normal follicle morphology, density, cell proliferation, apoptosis, and metabolism signaling pathways (BAX/BCL-2 ratio, CASPASE-3 and 9, ATP-6 genes, VEGF-A, and ERK-1/2 protein expression levels). Major outcomes revealed that the percentages of morphologically normal follicles and density were significantly decreased by cryopreservation. Ovarian tissue encapsulation using the 10FT formulation (with or without VEGF) could maintain the ERK-signaling cascade, which was comparable to the fresh control. Among the frozen-thawed cohorts, the BAX/BCL-2 ratio, CASPASE-3, CASPASE-9, and ATP-6 expression levels were unfavorable in the non-FT group. However, statistically different results, including VEGF-A expression levels, were not detected. Collectively, our present data demonstrated the first applicable biomaterial matrix for human ovarian tissue encapsulation which might create an optimal intra-ovarian cortex environment during cryopreservation. Further studies to optimize hydrogel polymerization should be expanded, given the potential benefits for cancer patients who wish to preserve fertility through ovarian tissue cryopreservation.

Engineering potent chimeric antigen receptor T cells by programming signaling during T-cell activation

Programming cell signaling during T-cell activation represents a simple strategy for improving the potency of therapeutic T-cell products. Stim-R technology (Lyell Immunopharma) is a customizable, degradable synthetic cell biomimetic that emulates physiologic, cell-like presentation of signal molecules to control T-cell activation. A breadth of Stim-R formulations with different anti-CD3/anti-CD28 (αCD3/αCD28) antibody densities and stoichiometries were screened for their effects on multiple metrics of T-cell function. We identified an optimized formulation that produced receptor tyrosine kinase-like orphan receptor 1 (ROR1)-targeted chimeric antigen receptor (CAR) T cells with enhanced persistence and polyfunctionality in vitro, as assessed in repeat-stimulation assays, compared with a benchmark product generated using a conventional T-cell-activating reagent. In transcriptomic analyses, CAR T cells activated with Stim-R technology showed downregulation of exhaustion-associated gene sets and retained a unique subset of stem-like cells with effector-associated gene signatures following repeated exposure to tumor cells. Compared with the benchmark product, CAR T cells activated using the optimized Stim-R technology formulation exhibited higher peak expansion, prolonged persistence, and improved tumor control in a solid tumor xenograft model. Enhancing T-cell products with Stim-R technology during T-cell activation may help improve therapeutic efficacy against solid tumors.

Tumor Microenvironment-Responsive Magnetotactic Bacteria-Based Multi-Drug Delivery Platform for MRI-Visualized Tumor Photothermal Chemodynamic Therapy

Cancer cells display elevated reactive oxygen species (ROS) and altered redox status. Herein, based on these characteristics, we present a multi-drug delivery platform, AMB@PDAP-Fe (APPF), from the magnetotactic bacterium AMB-1 and realize MRI-visualized tumor-microenvironment-responsive photothermal-chemodynamic therapy. The Fe3+ in PDAP-Fe is reduced by the GSH at the tumor site and is released in the form of highly active Fe2+, which catalyzes the generation of ROS through the Fenton reaction and inhibits tumor growth. At the same time, the significant absorption of the mineralized magnetosomes in AMB-1 cells in the NIR region enables them to efficiently convert near-infrared light into heat energy for photothermal therapy (PTT), to which PDAP also contributes. The heat generated in the PTT process accelerates the process of Fe2+ release, thereby achieving an enhanced Fenton reaction in the tumor microenvironment. In addition, the magnetosomes in AMB-1 are used as an MRI contrast agent, and the curing process is visualized. This tumor microenvironment-responsive MTB-based multi-drug delivery platform displays the potency to combat tumors and demonstrates the utility and practicality of understanding the cooperative molecular mechanism when designing multi-drug combination therapies.

Spiky Gold Nanoparticles, a Nanoscale Approach to Enhanced Ex Vivo T-Cell Activation

While existing synthetic technologies for ex vivo T-cell activation face challenges like suboptimal expansion rates and low effectiveness, artificial antigen-presenting cells (aAPCs) hold great promise for enhanced T-cell based therapies. In particular, gold nanoparticles (AuNPs), known for their biocompatibility, ease of synthesis, and versatile surface chemistry, are strong candidates for use as nanoscale aAPCs. In this study, we developed spiky AuNPs with branched geometries to present activating ligands to primary human T-cells. The special structure of spiky AuNPs enhances biomolecule loading capacity and significantly improves T-cell activation through multivalent binding of costimulatory ligands and receptors. Our spiky AuNPs outperform existing systems including Dynabeads and soluble activators by promoting greater polyclonal expansion of T-cells, boosting sustained cytokine production, and generating highly functional T-cells with reduced exhaustion. In addition, spiky AuNPs effectively activate and expand CD19 CAR-T cells while demonstrating increased in vitro cytotoxicity against target cells using fewer effector cells than Dynabeads. This study underscores the potential of spiky AuNPs as a powerful tool, bringing new opportunities to adoptive cell therapy applications.

Nucleation-Inhibited Emulsion Interfacial Assembled Polydopamine Microvesicles as Artificial Antigen-Presenting Cells

Albeit microemulsion systems have emerged as efficient platforms for fabricating tunable nano/microstructures, lack of understanding on the emulsion-interfacial assembly hindered the control of fabrication. Herein, a nucleation-inhibited microemulsion interfacial assembly method is proposed, which deviates from conventional interfacial nucleation approaches, for the synthesis of polydopamine microvesicles (PDA MVs). These PDA MVs exhibit an approximate diameter of 1 µm, showcasing a pliable structure reminiscent of cellular morphology. Through modifications of antibodies on the surface of PDA MVs, their capacity as artificial antigen presentation cells is evaluated. In comparison to solid nanoparticles, PDA MVs with cell-like structures show enhanced T-cell activation, resulting in a 1.5-fold increase in CD25 expression after 1 day and a threefold surge in PD-1 positivity after 7 days. In summary, the research elucidates the influence of nucleation and interfacial assembly in microemulsion polymerization systems, providing a direct synthesis method for MVs and substantiating their effectiveness as artificial antigen-presenting cells.

Nanomaterials Boost CAR-T Therapy for Solid Tumors

T cell engineering, particularly via chimeric antigen receptor (CAR) modifications for enhancing tumor specificity, has shown efficacy in treating hematologic malignancies. The extension of CAR-T cell therapy to solid tumors, however, is impeded by several challenges: The absence of tumor-specific antigens, antigen heterogeneity, a complex immunosuppressive tumor microenvironment, and physical barriers to cell infiltration. Additionally, limitations in CAR-T cell manufacturing capacity and the high costs associated with these therapies restrict their widespread application. The integration of nanomaterials into CAR-T cell production and application offers a promising avenue to mitigate these challenges. Utilizing nanomaterials in the production of CAR-T cells can decrease product variability and lower production expenses, positively impacting the targeting and persistence of CAR-T cells in treatment and minimizing adverse effects. This review comprehensively evaluates the use of various nanomaterials in the production of CAR-T cells, genetic modification, and in vivo delivery. It discusses their underlying mechanisms and potential for clinical application, with a focus on improving specificity and safety in CAR-T cell therapy.

Surface-Functionalized Microgels as Artificial Antigen-Presenting Cells to Regulate Expansion of T Cells

Artificial antigen-presenting cells (aAPCs) are currently used to manufacture T cells for adoptive therapy in cancer treatment, but a readily tunable and modular system can enable both rapid T cell expansion and control over T cell phenotype. Here, it is shown that microgels with tailored surface biochemical properties can serve as aAPCs to mediate T cell activation and expansion. Surface functionalization of microgels is achieved via layer-by-layer coating using oppositely charged polymers, forming a thin but dense polymer layer on the surface. This facile and versatile approach is compatible with a variety of coating polymers and allows efficient and flexible surface-specific conjugation of defined peptides or proteins. The authors demonstrate that tethering appropriate stimulatory ligands on the microgel surface efficiently activates T cells for polyclonal and antigen-specific expansion. The expansion, phenotype, and functional outcome of primary mouse and human T cells can be regulated by modulating the concentration, ratio, and distribution of stimulatory ligands presented on microgel surfaces as well as the stiffness and viscoelasticity of the microgels.

Mesoporous Silica Nanoparticles as an Ideal Platform for Cancer Immunotherapy: Recent Advances and Future Directions

Cancer immunotherapy recently transforms the traditional approaches against various cancer malignancies. Immunotherapy includes systemic and local treatments to enhance immune responses against cancer and involves strategies such as immune checkpoints, cancer vaccines, immune modulatory agents, mimetic antigen-presenting cells, and adoptive cell therapy. Despite promising results, these approaches still suffer from several limitations including lack of precise delivery of immune-modulatory agents to the target cells and off-target toxicity, among others, that can be overcome using nanotechnology. Mesoporous silica nanoparticles (MSNs) are investigated to improve various aspects of cancer immunotherapy attributed to the advantageous structural features of this nanomaterial. MSNs can be engineered to alter their properties such as size, shape, porosity, surface functionality, and adjuvanticity. This review explores the immunological properties of MSNs and the use of MSNs as delivery vehicles for immune-adjuvants, vaccines, and mimetic antigen-presenting cells (APCs). The review also details the current strategies to remodel the tumor microenvironment to positively reciprocate toward the anti-tumor immune cells and the use of MSNs for immunotherapy in combination with other anti-tumor therapies including photodynamic/thermal therapies to enhance the therapeutic effect against cancer. Last, the present demands and future scenarios for the use of MSNs for cancer immunotherapy are discussed.

Implantable CAR T cell factories enhance solid tumor treatment

Chimeric Antigen Receptor (CAR) T cell therapy has produced revolutionary success in hematological cancers such as leukemia and lymphoma. Nonetheless, its translation to solid tumors faces challenges due to manufacturing complexities, short-lived in vivo persistence, and transient therapeutic impact. We introduce 'Drydux' - an innovative macroporous biomaterial scaffold designed for rapid, efficient in-situ generation of tumor-specific CAR T cells. Drydux expedites CAR T cell preparation with a mere three-day turnaround from patient blood collection, presenting a cost-effective, streamlined alternative to conventional methodologies. Notably, Drydux-enabled CAR T cells provide prolonged in vivo release, functionality, and enhanced persistence exceeding 150 days, with cells transitioning to memory phenotypes. Unlike conventional CAR T cell therapy, which offered only temporary tumor control, equivalent Drydux cell doses induced lasting tumor remission in various animal tumor models, including systemic lymphoma, peritoneal ovarian cancer, metastatic lung cancer, and orthotopic pancreatic cancer. Drydux's approach holds promise in revolutionizing solid tumor CAR T cell therapy by delivering durable, rapid, and cost-effective treatments and broadening patient accessibility to this groundbreaking therapy.

Mechanoimmunology in the solid tumor microenvironment

The tumor microenvironment (TME) is a complex and dynamic ecosystem that adjoins the cancer cells within solid tumors and comprises distinct components such as extracellular matrix, stromal and immune cells, blood vessels, and an abundance of signaling molecules. In recent years, the mechanical properties of the TME have emerged as critical determinants of tumor progression and therapeutic response. Aberrant mechanical cues, including altered tissue architecture and stiffness, contribute to tumor progression, metastasis, and resistance to treatment. Moreover, burgeoning immunotherapies hold great promise for harnessing the immune system to target and eliminate solid malignancies; however, their success is hindered by the hostile mechanical landscape of the TME, which can impede immune cell infiltration, function, and persistence. Consequently, understanding TME mechanoimmunology - the interplay between mechanical forces and immune cell behavior - is essential for developing effective solid cancer therapies. Here, we review the role of TME mechanics in tumor immunology, focusing on recent therapeutic interventions aimed at modulating the mechanical properties of the TME to potentiate T cell immunotherapies, and innovative assays tailored to evaluate their clinical efficacy.

Immunological nanomaterials to combat cancer metastasis

Metastasis causes greater than 90% of cancer-associated deaths, presenting huge challenges for detection and efficient treatment of cancer due to its high heterogeneity and widespread dissemination to various organs. Therefore, it is imperative to combat cancer metastasis, which is the key to achieving complete cancer eradication. Immunotherapy as a systemic approach has shown promising potential to combat metastasis. However, current clinical immunotherapies are not effective for all patients or all types of cancer metastases owing to insufficient immune responses. In recent years, immunological nanomaterials with intrinsic immunogenicity or immunomodulatory agents with efficient loading have been shown to enhance immune responses to eliminate metastasis. In this review, we would like to summarize various types of immunological nanomaterials against metastasis. Moreover, this review will summarize a series of immunological nanomaterial-mediated immunotherapy strategies to combat metastasis, including immunogenic cell death, regulation of chemokines and cytokines, improving the immunosuppressive tumour microenvironment, activation of the STING pathway, enhancing cytotoxic natural killer cell activity, enhancing antigen presentation of dendritic cells, and enhancing chimeric antigen receptor T cell therapy. Furthermore, the synergistic anti-metastasis strategies based on the combinational use of immunotherapy and other therapeutic modalities will also be introduced. In addition, the nanomaterial-mediated imaging techniques (e.g., optical imaging, magnetic resonance imaging, computed tomography, photoacoustic imaging, surface-enhanced Raman scattering, radionuclide imaging, etc.) for detecting metastasis and monitoring anti-metastasis efficacy are also summarized. Finally, the current challenges and future prospects of immunological nanomaterial-based anti-metastasis are also elucidated with the intention to accelerate its clinical translation.

Molecular mechanisms underlying the modulation of T-cell proliferation and cytotoxicity by immobilized CCL21 and ICAM1

BACKGROUND

Adoptive cancer immunotherapy, using engineered T-cells, expressing chimeric antigen receptor or autologous tumor infiltrating lymphocytes became, in recent years, a major therapeutic approach for diverse types of cancer. However, despite the transformative potential of adoptive cancer immunotherapy, this field still faces major challenges, manifested by the apparent decline of the cytotoxic capacity of effector CD8+ T cells upon their expansion. To address these challenges, we have developed an ex vivo "synthetic immune niche" (SIN), composed of immobilized CCL21 and ICAM1, which synergistically induce an efficient expansion of antigen-specific CD8+ T cells while retaining, and even enhancing their cytotoxic potency.

METHODS

To explore the molecular mechanisms through which a CCL21+ICAM1-based SIN modulates the interplay between the proliferation and cytotoxic potency of antigen-activated and CD3/CD28-activated effector CD8+ T cells, we performed integrated analysis of specific differentiation markers via flow cytometry, together with gene expression profiling.

RESULTS

On day 3, the transcriptomic effect induced by the SIN was largely similar for both dendritic cell (DC)/ovalbumin (OVA)-activated and anti-CD3/CD28-activated cells. Cell proliferation increased and the cells exhibited high killing capacity. On day 4 and on, the proliferation/cytotoxicity phenotypes became radically "activation-specific"; The DC/OVA-activated cells lost their cytotoxic activity, which, in turn, was rescued by the SIN treatment. On longer incubation, the cytotoxic activity further declined, and on day7, could not be rescued by the SIN. SIN stimulation following activation with anti-CD3/CD28 beads induced a major increase in the proliferative phenotype while transiently suppressing their cytotoxicity for 2-3 days and fully regaining their killing activity on day 7. Potential molecular regulatory pathways of the SIN effects were identified, based on transcriptomic and multispectral imaging profiling.

CONCLUSIONS

These data indicate that cell proliferation and cytotoxicity are negatively correlated, and the interplay between them is differentially regulated by the mode of initial activation. The SIN stimulation greatly enhances the cell expansion, following both activation modes, while displaying high survival and cytotoxic potency at specific time points following stimulation, suggesting that it could effectively reinforce adoptive cancer immunotherapy.

Enzyme-Instructed Photoactivatable Supramolecular Antigens on Cancer Cell Membranes for Precision-Controlled T-Cell-Based Cancer Immunotherapy

Cancer immunotherapies based on cytotoxic CD8+ T lymphocytes (CTLs) are highly promising for cancer treatment. The specific interaction between T-cell receptors and peptide-MHC-I complexes (pMHC-I) on cancer cell membranes critically determines their therapeutic outcomes. However, the lack of appropriate endogenous antigens for MHC-I presentation disables tumor recognition by CTLs. By devising three antigen-loaded self-assembling peptides of pY-K(Ag)-ERGD, pY-K(Ag)-E, and Y-K(Ag)-ERGD to noncovalently generate light-activatable supramolecular antigens at tumor sites in different manners, we report pY-K(Ag)-ERGD as a promising candidate to endow tumor cells with pMHC-I targets on demand. Specifically, pY-K(Ag)-ERGD first generates low-antigenic supramolecular antigens on cancer cell membranes, and a successive light pulse allows antigen payloads to efficiently release from the supramolecular scaffold, directly producing antigenic pMHC-I. Intravenous administration of pY-K(Ag)-ERGD enables light-controlled tumor inhibition when combined with adoptively transferred antigen-specific CTLs. Our strategy is feasible for broadening tumor antigen repertoires for T-cell immunotherapies and advancing precision-controlled T-cell immunotherapies.

Biodegradable pyroptosis inducer with multienzyme-mimic activity kicks up reactive oxygen species storm for sensitizing immunotherapy

Triggering pyroptosis is a major new weathervane for activating tumor immune response. However, biodegradable pyroptosis inducers for the safe and efficient treatment of tumors are still scarce. Herein, a novel tumor microenvironment (TME)-responsive activation nanoneedle for pyroptosis induction, copper-tannic acid (CuTA), was synthesized and combined with the sonosensitizer Chlorin e6 (Ce6) to form a pyroptosis amplifier (CuTA-Ce6) for dual activation and amplification of pyroptosis by exogenous ultrasound (US) and TME. It was demonstrated that Ce6-triggered sonodynamic therapy (SDT) further enhanced the cellular pyroptosis caused by CuTA, activating the body to develop a powerful anti-tumor immune response. Concretely, CuTA nanoneedles with quadruple mimetic enzyme activity could be activated to an "active" state in the TME, destroying the antioxidant defense system of the tumor cells through self-destructive degradation, breaking the "immunosilent" TME, and thus realizing the pyroptosis-mediated immunotherapy with fewer systemic side effects. Considering the outstanding oxygen-producing capacity of CuTA and the distinctive advantages of US, the sonosensitizer Ce6 was attached to CuTA via an amide reaction, which further amplified the pyroptosis and sensitized pyroptosis-induced immunotherapy with the two-pronged strategy of CuTA enzyme-catalyzed cascade and US-driven SDT pathway to generate a "reactive oxygen species (ROS) storm". Conclusively, this work provided a representative paradigm for achieving safe, reliable and efficient pyroptosis, which was further enhanced by SDT for more robust immunotherapy.

T Cell Activators Exhibit Distinct Downstream Effects on Chimeric Antigen Receptor T Cell Phenotype and Function

T cell activation is an essential step in chimeric Ag receptor (CAR) T (CAR T) cell manufacturing and is accomplished by the addition of activator reagents that trigger the TCR and provide costimulation. We explore several T cell activation reagents and examine their effects on key attributes of CAR T cell cultures, such as activation/exhaustion markers, cell expansion, gene expression, and transduction efficiency. Four distinct activators were examined, all using anti-CD3 and anti-CD28, but incorporating different mechanisms of delivery: Dynabeads (magnetic microspheres), TransAct (polymeric nanomatrix), Cloudz (alginate hydrogel), and Microbubbles (lipid membrane containing perfluorocarbon gas). Clinical-grade lentiviral vector was used to transduce cells with a bivalent CD19/CD22 CAR, and cell counts and flow cytometry were used to monitor the cells throughout the culture. We observed differences in CD4/CD8 ratio when stimulating with the Cloudz activator, where there was a significant skewing toward CD8 T cells. The naive T cell subset expressing CD62L+CCR7+CD45RA+ was the highest in all donors when stimulating with Dynabeads, whereas effector/effector memory cells were highest when using the Cloudz. Functional assays demonstrated differences in killing of target cells and proinflammatory cytokine secretion, with the highest killing from the Cloudz-stimulated cells among all donors. This study demonstrates that the means by which these stimulatory Abs are presented to T cells contribute to the activation, resulting in differing effects on CAR T cell function. These studies highlight important differences in the final product that should be considered when manufacturing CAR T cells for patients in the clinic.

Engineering Improved CAR T Cell Products with A Multi-Cytokine Particle Platform for Hematologic and Solid Tumors

Despite the remarkable clinical efficacy of chimeric antigen receptor (CAR) T cells in hematological malignancies, only a subset of patients achieves a durable complete response (dCR). DCR has been correlated with CAR T cell products enriched with T cells memory phenotypes. Therefore, reagents that consistently promote memory phenotypes during the manufacturing of CAR T cells have the potential to significantly improve clinical outcomes. A novel modular multi-cytokine particle (MCP) platform is developed that combines the signals necessary for activation, costimulation, and cytokine support into a single "all-in-one" stimulation reagent for CAR T cell manufacturing. This platform allows for the assembly and screening of compositionally diverse MCP libraries to identify formulations tailored to promote specific phenotypes with a high degree of flexibility. The approach is leveraged to identify unique MCP formulations that manufacture CAR T cell products from diffuse large B cell patients   with increased proportions of memory-like phenotypes MCP-manufactured CAR T cells demonstrate superior anti-tumor efficacy in mouse models of lymphoma and ovarian cancer through enhanced persistence. These findings serve as a proof-of-principle of the powerful utility of the MCP platform to identify "all-in-one" stimulation reagents that can improve the effectiveness of cell therapy products through optimal manufacturing.

Engineering customized nanovaccines for enhanced cancer immunotherapy

Nanovaccines have gathered significant attention for their potential to elicit tumor-specific immunological responses. Despite notable progress in tumor immunotherapy, nanovaccines still encounter considerable challenges such as low delivery efficiency, limited targeting ability, and suboptimal efficacy. With an aim of addressing these issues, engineering customized nanovaccines through modification or functionalization has emerged as a promising approach. These tailored nanovaccines not only enhance antigen presentation, but also effectively modulate immunosuppression within the tumor microenvironment. Specifically, they are distinguished by their diverse sizes, shapes, charges, structures, and unique physicochemical properties, along with targeting ligands. These features of nanovaccines facilitate lymph node accumulation and activation/regulation of immune cells. This overview of bespoke nanovaccines underscores their potential in both prophylactic and therapeutic applications, offering insights into their future development and role in cancer immunotherapy.

Lyophilized lymph nodes for improved delivery of chimeric antigen receptor T cells

Lymph nodes are crucial organs of the adaptive immune system, orchestrating T cell priming, activation and tolerance. T cell activity and function are highly regulated by lymph nodes, which have a unique structure harbouring distinct cells that work together to detect and respond to pathogen-derived antigens. Here we show that implanted patient-derived freeze-dried lymph nodes loaded with chimeric antigen receptor T cells improve delivery to solid tumours and inhibit tumour recurrence after surgery. Chimeric antigen receptor T cells can be effectively loaded into lyophilized lymph nodes, whose unaltered meshwork and cytokine and chemokine contents promote chimeric antigen receptor T cell viability and activation. In mouse models of cell-line-derived human cervical cancer and patient-derived pancreatic cancer, delivery of chimeric antigen receptor T cells targeting mesothelin via the freeze-dried lymph nodes is more effective in preventing tumour recurrence when compared to hydrogels containing T-cell-supporting cytokines. This tissue-mediated cell delivery strategy holds promise for controlled release of various cells and therapeutics with long-term activity and augmented function.

Advances in nano-immunotherapy for hematological malignancies

Hematological malignancies (HMs) encompass a diverse group of blood neoplasms with significant morbidity and mortality. Immunotherapy has emerged as a validated and crucial treatment modality for patients with HMs. Despite notable advancements having been made in understanding and implementing immunotherapy for HMs over the past decade, several challenges persist. These challenges include immune-related adverse effects, the precise biodistribution and elimination of therapeutic antigens in vivo, immune tolerance of tumors, and immune evasion by tumor cells within the tumor microenvironment (TME). Nanotechnology, with its capacity to manipulate material properties at the nanometer scale, has the potential to tackle these obstacles and revolutionize treatment outcomes by improving various aspects such as drug targeting and stability. The convergence of nanotechnology and immunotherapy has given rise to nano-immunotherapy, a specialized branch of anti-tumor therapy. Nanotechnology has found applications in chimeric antigen receptor T cell (CAR-T) therapy, cancer vaccines, immune checkpoint inhibitors, and other immunotherapeutic strategies for HMs. In this review, we delineate recent developments and discuss current challenges in the field of nano-immunotherapy for HMs, offering novel insights into the potential of nanotechnology-based therapeutic approaches for these diseases.

Multimodal probing of T-cell recognition with hexapod heterostructures

Studies using antigen-presenting systems at the single-cell and ensemble levels can provide complementary insights into T-cell signaling and activation. Although crucial for advancing basic immunology and immunotherapy, there is a notable absence of synthetic material toolkits that examine T cells at both levels, and especially those capable of single-molecule-level manipulation. Here we devise a biomimetic antigen-presenting system (bAPS) for single-cell stimulation and ensemble modulation of T-cell recognition. Our bAPS uses hexapod heterostructures composed of a submicrometer cubic hematite core (α-Fe2O3) and nanostructured silica branches with diverse surface modifications. At single-molecule resolution, we show T-cell activation by a single agonist peptide-loaded major histocompatibility complex; distinct T-cell receptor (TCR) responses to structurally similar peptides that differ by only one amino acid; and the superior antigen recognition sensitivity of TCRs compared with that of chimeric antigen receptors (CARs). We also demonstrate how the magnetic field-induced rotation of hexapods amplifies the immune responses in suspended T and CAR-T cells. In addition, we establish our bAPS as a precise and scalable method for identifying stimulatory antigen-specific TCRs at the single-cell level. Thus, our multimodal bAPS represents a unique biointerface tool for investigating T-cell recognition, signaling and function.

Surface chemical modification of poly(dimethylsiloxane) for stabilizing antibody immobilization and T cell cultures

Advances in cell immunotherapy underscore the need for effective methods to produce large populations of effector T cells, driving growing interest in T-cell bioprocessing and immunoengineering. Research suggests that T cells demonstrate enhanced expansion and differentiation on soft matrices in contrast to rigid ones. Nevertheless, the influence of antibody conjugation chemistry on these processes remains largely unexplored. In this study, we examined the effect of antibody conjugation chemistry on T cell activation, expansion and differentiation using a soft and biocompatible polydimethylsiloxane (PDMS) platform. We rigorously evaluated three distinct immobilization methods, beginning with the use of amino-silane (PDMS-NH2-Ab), followed by glutaraldehyde (PDMS-CHO-Ab) or succinic acid anhydride (PDMS-COOH-Ab) activation, in addition to the conventional physical adsorption (PDMS-Ab). By employing both stable amide bonds and reducible Schiff bases, antibody conjugation significantly enhanced antibody loading and density compared to physical adsorption. Furthermore, we discovered that the PDMS-COOH-Ab surface significantly promoted IL-2 secretion, CD69 expression, and T cell expansion compared to the other groups. Moreover, we observed that both PDMS-COOH-Ab and PDMS-NH2-Ab surfaces exhibited a tendency to induce the differentiation of naïve CD4+ T cells into Th1 cells, whereas the PDMS-Ab surface elicited a Th2-biased immunological response. These findings highlight the importance of antibody conjugation chemistry in the design and development of T cell culture biomaterials. They also indicate that PDMS holds promise as a material for constructing culture platforms to modulate T cell activation, proliferation, and differentiation.

In vitro encapsulation and expansion of T and CAR-T cells using 3D synthetic thermo-responsive matrices

Suspension cell culture and rigid commercial substrates are the most common methods to clinically manufacture therapeutic CAR-T cells ex vivo. However, suspension culture and nano/micro-scale commercial substrates poorly mimic the microenvironment where T cells naturally develop, leading to profound impacts on cell proliferation and phenotype. To overcome this major challenge, macro-scale substrates can be used to emulate that environment with higher precision. This work employed a biocompatible thermo-responsive material with tailored mechanical properties as a potential synthetic macro-scale scaffold to support T cell encapsulation and culture. Cell viability, expansion, and phenotype changes were assessed to study the effect of two thermo-responsive hydrogel materials with stiffnesses of 0.5 and 17 kPa. Encapsulated Pan-T and CAR-T cells were able to grow and physically behave similar to the suspension control. Furthermore, matrix stiffness influenced T cell behavior. In the softer polymer, T cells had higher activation, differentiation, and maturation after encapsulation obtaining significant cell numbers. Even when terpolymer encapsulation affected the CAR-T cell viability and expansion, CAR T cells expressed favorable phenotypical profiles, which was supported with cytokines and lactate production. These results confirmed the biocompatibility of the thermo-responsive hydrogels and their feasibility as a promising 3D macro-scale scaffold for in vitro T cell expansion that could potentially be used for cell manufacturing process.

Metabolic Modulation of Kynurenine Based on Kynureninase-Loaded Nanoparticle Depot Overcomes Tumor Immune Evasion in Cancer Immunotherapy

Evading recognition of immune cells is a well-known strategy of tumors used for their survival. One of the immune evasion mechanisms is the synthesis of kynurenine (KYN), a metabolite of tryptophan, which suppresses the effector T cells. Therefore, lowering the KYN concentration can be an efficient antitumor therapy by restoring the activity of immune cells. Recently, kynureninase (KYNase), which is an enzyme transforming KYN into anthranilate, was demonstrated to show the potential to decrease KYN concentration and inhibit tumor growth. However, due to the limited bioavailability and instability of proteins in vivo, it has been challenging to maintain the KYNase concentration sufficiently high in the tumor microenvironment (TME). Here, we developed a nanoparticle system loaded with KYNase, which formed a Biodegradable and Implantable Nanoparticle Depot named 'BIND' following subcutaneous injection. The BIND sustainably supplied KYNase around the TME while located around the tumor, until it eventually degraded and disappeared. As a result, the BIND system enhanced the proliferation and cytokine production of effector T cells in the TME, followed by tumor growth inhibition and increased mean survival. Finally, we showed that the BIND carrying KYNase significantly synergized with PD-1 blockade in three mouse models of colon cancer, breast cancer, and melanoma.

A Novel Approach for Colloidal Lithography: From Dry Particle Assembly to High-Throughput Nanofabrication

We introduce a novel approach for colloidal lithography based on the dry particle assembly into a dense monolayer on an elastomer, followed by mechanical transfer to a substrate of any material and curvature. This method can be implemented either manually or automatically and it produces large area patterns with the quality obtained by the state-of-the-art colloidal lithography at a very high throughput. We first demonstrated the fabrication of nanopatterns with a periodicity ranging between 200 nm and 2 μm. We then demonstrated two nanotechnological applications of this approach. The first one is antireflective structures, fabricated on silicon and sapphire, with different geometries including arrays of bumps and holes and adjusted for different spectral ranges. The second one is smart 3D nanostructures for mechanostimulation of T cells that are used for their effective proliferation, with potential application in cancer immunotherapy. This new approach unleashes the potential of bottom-up nanofabrication and paves the way for nanoscale devices and systems in numerous applications.

Lymph node-biomimetic scaffold boosts CAR-T therapy against solid tumor

The limited infiltration and persistence of chimeric antigen receptor (CAR)-T cells is primarily responsible for their treatment deficits in solid tumors. Here, we present a three-dimensional scaffold, inspired by the physiological process of T-cell proliferation in lymph nodes. This scaffold gathers the function of loading, delivery, activation and expansion for CAR-T cells to enhance their therapeutic effects on solid tumors. This porous device is made from poly(lactic-co-glycolic acid) by a microfluidic technique with the modification of T-cell stimulatory signals, including anti-CD3, anti-CD28 antibodies, as well as cytokines. This scaffold fosters a 50-fold CAR-T cell expansion in vitro and a 15-fold cell expansion in vivo. Particularly, it maintains long-lasting expansion of CAR-T cells for up to 30 days in a cervical tumor model and significantly inhibits the tumor growth. This biomimetic delivery strategy provides a versatile platform of cell delivery and activation for CAR-T cells in treating solid tumors.

Bridging the gender gap in autoimmunity with T-cell-targeted biomaterials

Autoimmune diseases are caused by malfunctions of the immune system and generally impact women at twice the frequency of men. Many of the most serious autoimmune diseases are accompanied by a dysregulation of T-cell phenotype, both regarding the ratio of CD4+ to CD8+ T-cells and proinflammatory versus regulatory phenotypes. Biomaterials, in the form of particles and hydrogels, have shown promise in ameliorating this dysregulation both in vivo and ex vivo. In this review, we explore the role of T-cells in autoimmune diseases, particularly those with high incidence rates in women, and evaluate the promise and efficacy of innovative biomaterial-based approaches for targeting T-cells.

An injectable hydrogel microsphere-integrated training court to inspire tumor-infiltrating T lymphocyte potential

Although tumor-infiltrating T lymphocytes (TIL-Ts) play a crucial role in solid tumor immunotherapy, their clinical application has been limited because of the immunosuppressive microenvironment. Herein, we developed an injectable hydrogel microsphere-integrated training court (MS-ITC) to inspire the function of TIL-Ts and amplify TIL-Ts, through grafting with anti-CD3 and anti-CD28 antibodies and bovine serum albumin nanoparticles encapsulated with IL-7 and IL-15. MS-ITC provided the T-cell receptor and co-stimulatory signals required for TIL-Ts activation and IL-7/IL-15 signals for TIL-Ts expansion. Afterward, the MS-ITC was injected locally into the osteosarcoma tumor tissue in mice. MS-ITC suppressed the growth of primary osteosarcoma by more than 95 %, accompanied with primed and expanded TIL-Ts in the tumor tissues, compromising significantly increased CD8+ T and memory T cells, thereby enhancing the anti-tumor effect. Together, this work provides an injectable hydrogel microsphere-integrated training platform capable of inspiring TIL-Ts potential for a range of solid tumor immunotherapy.

Differentiation, maturation, and collection of THP-1-derived dendritic cells based on a PEG hydrogel culture platform

PURPOSE

Dendritic cell (DC) is a spearhead responsible for immune response and surrounded by extracellular matrix in three-dimensional (3D) tissue. Nevertheless, conventional DC culture has relied on suspension or two-dimensional (2D) tissue culture plate (TCP)-based culture system. This culture condition often fails to recapitulate the physiological behavior of DC in real tissue. In this work, the effect of culture condition on DC physiology was explored with varying 3D hydrogel property (i.e., degradability, adhesion, and stiffness). In particular, DC differentiation and maturation in 3D were evaluated comparing the conventional TCP-based culture condition.

METHOD

THP-1 cells were encapsulated in poly(ethylene glycol) (PEG) hydrogel via thiol-ene photocrosslinking with non-degradable or proteolytically degradable peptide crosslinker. Hydrogel stiffness was manipulated by controlling the concentration of crosslinker. The metabolic activities and cytotoxicity of the encapsulated cells were measured by resazurin and Live/Dead assays, respectively. Cell harvesting was conducted via enzymatic degradation using α-chymotrypsin, and differentiation and maturation of the liberated DCs were evaluated by quantitative polymerase chain reaction and flow cytometry.

RESULTS

THP-1 cells well proliferated in the soft degradable hydrogel with a higher metabolic activity. However, the stiff matrix inhibited cell growth in 3D. The gene expression assay indicated that the 3D hydrogel condition was superior to 2D culture in terms of differentiation and maturation of DC. Interestingly, the stiffness of matrix was important factor in DC function. In the stiff hydrogel, the expression levels of differentiation and maturation markers were higher compared to the low stiffness hydrogel. The mature DCs caged in the hydrogel matrix were harvested after short enzymatic digestion of hydrogel and the liberated cells had over 90% viability. The flow cytometric result revealed that the proportion of CD80 + /CD86 + cells from the stiff hydrogel was relatively higher than cells either from 2D or soft hydrogel in 3D.

CONCLUSION

The collected evidence indicated that the proteolytically degradable PEG hydrogel matrix promoted DC differentiation and maturation. In addition, the matrix stiffness control could manipulate the marker expressions of differentiation and maturation. Particularly, the mature DC was successfully collected from the hydrogel matrix. These results highlighted the PEG hydrogel-based DC culture might be a useful tool for potential DC-based immunotherapies.