Delivery of CAR-T cells in a transient injectable stimulatory hydrogel niche improves treatment of solid tumors

Gel@CAT-L hydrogel mediates mitochondrial unfolded protein response to regulate reactive oxygen species and mitochondrial homeostasis in osteoarthritis

OBJECTIVE

This study investigates the role of Gelatin-Catalase (Gel@CAT)-L hydrogel in mediating reactive oxygen species (ROS) production and maintaining mitochondrial homeostasis through SIRT3-mediated unfolded protein response (UPRmt), while exploring its involvement in the molecular mechanism of osteoarthritis (OA).

METHODS

Self-assembled Gel@CAT-L hydrogels were fabricated and characterized using transmission electron microscopy, mechanical testing, external release property evaluation, and oxygen production measurement. Biocompatibility was assessed via live/dead cell staining and CCK8 assays. An OA mouse model was established using destabilization of the medial meniscus (DMM) surgery. X-ray and micro-CT imaging were employed to evaluate the structural integrity of the mouse knee joints, while histological staining was used to assess cartilage degeneration. Immunohistochemistry was performed to analyze the expression of proteins including Col2a1, Aggrecan, MMP13, ADAMTS5, SIRT3, PINK1, and Parkin. Multi-omics analyses-encompassing high-throughput sequencing, proteomics, and metabolomics-were conducted to identify key genes and metabolic pathways targeted by Gel@CAT-L hydrogel intervention in OA. Immunofluorescence techniques were utilized to measure ROS levels, mitochondrial membrane potential, and the expression of SIRT3, PINK1, Parkin, LYSO, LC3B, Col2a1, and MMP13 in primary mouse chondrocytes and mouse knee joints. Flow cytometry was applied to quantify ROS-positive cells. RT-qPCR analysis was conducted to determine mRNA levels of Aggrecan, Col2a1, ADAMTS5, MMP13, SIRT3, mtDNA, HSP60, LONP1, CLPP, and Atf5 in primary mouse chondrocytes, mouse knee joints, and human knee joints. Western blotting was performed to measure protein expression levels of SIRT3, HSP60, LONP1, CLPP, and Atf5 in both primary mouse chondrocytes and mouse knee joints. Additionally, 20 samples each from the control (CON) and OA groups were collected for analysis. Hematoxylin and eosin staining was used to evaluate cartilage degeneration in human knee joints. The Mankin histological scoring system quantified the degree of cartilage degradation, while immunofluorescence analyzed SIRT3 protein expression in human knee joints.

RESULTS

In vitro experiments demonstrated that self-assembled Gel@CAT-L hydrogels exhibited excellent biodegradability and oxygen-releasing capabilities, providing a stable three-dimensional environment conducive to cell viability and proliferation while reducing ROS levels. Multi-omics analysis identified SIRT3 as a key regulatory gene in mitigating OA and revealed its central role in the UPRmt pathway. Furthermore, Gel@CAT-L was confirmed to regulate mitochondrial homeostasis. Both in vitro experiments and in vivo mouse model studies confirmed that Gel@CAT-L significantly reduced ROS levels and regulated mitochondrial autophagy by activating the SIRT3-mediated UPRmt pathway, thereby improving the pathological state of OA. Clinical trials indicated downregulation of SIRT3 and UPRmt-related proteins in OA patients.

CONCLUSION

Gel@CAT-L hydrogel activates SIRT3-mediated UPRmt to regulate ROS and mitochondrial homeostasis, providing potential therapeutic benefits for OA.

Biomaterial-Driven 3D Scaffolds for Immune Cell Expansion toward Personalized Immunotherapy

Immunotherapy has emerged as a transformative medical approach in recent years, providing novel treatments for cancer eradication, autoimmune disorders, and infectious diseases. Fundamental to the success of therapy is the enrichment of the immune cell population, particularly T cells, natural killer cells, and dendritic cells. However, achieving a robust and long-term proliferation of immune cells is still challenging both in vivo and ex vivo. In vivo expansion leverages the patient's natural microenvironment and regulatory mechanisms through therapeutic interventions like immune checkpoint inhibitors, cytokine therapy, and targeted antibodies. This approach fosters long-term immune memory and sustained protection. In contrast, ex vivo expansion involves isolation, manipulation, and expansion of the immune cells under controlled conditions before reinfusion, allowing for precise control over the process and generating potent immune cell populations. Hydrogels, due to their tunable biomechanical properties, high biocompatibility, and ability to mimic the extracellular matrix, provide an ideal platform for both in vivo and ex vivo immune cell expansion. For instance, hydrogel-based scaffolds or beads can facilitate a controlled and efficient expansion of immune cells ex vivo, whereas injectable and implantable hydrogels can provide innovative solutions for enhancing immune cell activity within the patient supporting prolonged immune cell activity. This review aims to elucidate the importance of hydrogel-based strategies in immune cell expansion, advancing the development of effective, personalized immunotherapies to improve patient outcomes. STATEMENT OF SIGNIFICANCE: This review highlights the transformative potential of hydrogel-based 3D scaffolds in advancing personalized immunotherapy. By integrating in vivo and ex vivo strategies, hydrogels provide an innovative platform to enhance immune cell expansion, addressing critical challenges in immunotherapy. The discussion emphasizes the unique biomechanical and biochemical tunability of hydrogels, enabling precise mimicry of the extracellular matrix to support T cell proliferation, activation, and memory formation. These advances offer scalable, cost-effective solutions for producing high-quality immune cells, contributing to more effective cancer treatments, autoimmune disease management, and infectious disease control. By bridging materials science and immunology, this work underscores the pivotal role of hydrogels in shaping the future of immune-based therapies.

Subtypes of tumor-associated neutrophils and their roles in cancer immunotherapy

Neutrophils are essential components of the innate immune system. Tumor-associated neutrophils (TANs) are shaped by tumor microenvironment (TME), leading to significant heterogeneity in biological characteristics and functions. Recent advances in single-cell sequencing have revealed a wide array of TAN subtypes, while a comprehensive classification system is still lacking. This review aims to summarize the alterations observed in TAN subgroups following cancer immunotherapy, and identify the distinctions and commonalities between pro-tumor and anti-tumor subgroups. Current progress of preclinical and clinical studies is also highlighted, involving novel therapies targeting TANs.

Regulating Intratumoral Fungi With Hydrogels: A Novel Approach to Modulating the Tumor Microbiome for Cancer Therapy

BACKGROUND

Fungi in tumors act as a double-edged sword, potentially worsening or alleviating malignancy based on the ecological balance within the tumor microenvironment (TME). Hydrogels, as innovative drug delivery systems, are poised to redefine treatment paradigms. As advanced biomaterials, they offer a versatile platform for encapsulating and releasing antifungal agents and immunomodulators, responding to the TME's unique demands.

METHODS

We have conducted and collated numerous relevant reviews and studies in recent years from three aspects: Hydrogels, intra-tumoral fungi, and tumor microbe microenvironment, in the hope of identifying the connections between hydrogels and intra-tumoral microbes.

RESULTS

This review underscores the crucial role of intra-tumoral microbes, particularly fungi, in tumorigenesis, progression, and treatment efficacy. At the same time, we concentrated on the findings of hydrogels investigations, with their remarkable adaptability to the tumor microenvironment emerge as intelligent drug delivery systems.

CONCLUSIONS

Hydrogels unique ability to precisely target and modulate the tumor microflora, including fungi, endows them with a significant edge in enhancing treatment efficacy. This innovative approach not only holds great promise for improving cancer therapy outcomes but also paves the way for developing novel strategies to control metastasis and prevent cancer recurrence.

Harnessing nano-delivery systems to un-cover the challenges for cervical cancer therapy

Cervical cancer (CC) remains a prevalent malignancy among women, with current therapeutic strategies facing significant challenges in curbing its rising incidence. Nano-delivery systems have emerged as a promising approach to hinder CC progression. This review provides a comprehensive examination of CC pathogenesis and its physiological characteristics while focusing on applying various nano-delivery systems in CC therapy. Specifically, it highlights the potential of both internal (e.g., pH, reactive oxygen species, glutathione) and external (e.g., Photo, magnetism, sound waves, microwaves, electricity) stimuli-responsive nano-delivery platforms to enhance therapeutic efficacy. The challenges of nano-delivery systems in CC therapy, encompassing in vivo stability, biosafety, distribution, and metabolic processes, are addressed, along with potential remedies. Additionally, the review underscores recent preclinical advances in nano-delivery systems for CC therapy. By thoroughly exploring nanomaterial applications, this review provides valuable perspectives for advancing CC treatment and stimulating future research and innovation in this domain.

Generation of an inflammatory niche in a hydrogel depot through recruitment of key immune cells improves efficacy of mRNA vaccines

Messenger RNA (mRNA) delivered in lipid nanoparticles (LNPs) rose to the forefront of vaccine candidates during the COVID-19 pandemic due to scalability, adaptability, and potency. Yet, there remain critical areas for improvements of these vaccines in durability and breadth of humoral responses. In this work, we explore a modular strategy to target mRNA/LNPs to antigen-presenting cells with an injectable polymer-nanoparticle (PNP) hydrogel technology, which recruits key immune cells and forms an immunological niche in vivo. We characterize this niche on a single-cell level and find it is highly tunable through incorporation of adjuvants like MPLAs and 3M-052. Delivering commercially available severe acute respiratory syndrome coronavirus 2 mRNA vaccines in PNP hydrogels improves the durability and quality of germinal center reactions, and the magnitude, breadth, and durability of humoral responses. The tunable immune niche formed within PNP hydrogels effectively skews immune responses based on encapsulated adjuvants, creating opportunities to precisely modulate mRNA/LNP vaccines for various indications from infectious diseases to cancers.

Pharmacokinetics-Based Design of Subcutaneous Controlled Release Systems for Biologics

Protein therapeutics have emerged as an exceedingly promising treatment modality in recent times but are predominantly given as intravenous administration. Transitioning to subcutaneous (SC) administration of these therapies could significantly enhance patient convenience by enabling at-home administration, thereby potentially reducing the overall cost of treatment. Approaches that enable sustained delivery of subcutaneously administered biologics offer further advantages in terms of less frequent dosing and better patient compliance. Controlled release technologies, such as hydrogels and subcutaneous implantable technologies, present exciting solutions by enabling the gradual release of biologics from the delivery system. Despite their substantial potential, significant hurdles remain in appropriately applying and integrating these technologies with the ongoing development of complex biologic-based therapies. We evaluate the potential impact of subcutaneously delivered controlled release systems on the downstream pharmacokinetics (PK) of several FDA-approved biologics by employing rigorous mathematical analysis and predictive PK simulations. By leveraging linear time-invariant (LTI) systems theory, we provide a robust framework for understanding and optimizing the release dynamics of these technologies. We demonstrate simple quantitative metrics and approaches that can inform the design and implementation of controlled release technologies. The findings highlight key opportunity areas to reduce dosing frequency, stabilize concentration profiles, and synergize the codelivery of biologics, calling for collaboration between drug delivery and PK scientists to create the most convenient, optimized, and effective precision therapies.

Highly Extensible Physically Crosslinked Hydrogels for High-Speed 3D Bioprinting

Hydrogels have emerged as promising materials for bioprinting and many other biomedical applications due to their high degree of biocompatibility and ability to support and/or modulate cell viability and function. Yet, many hydrogel bioinks have suffered from low efficiency due to limitations on accessible printing speeds, often limiting cell viability and/or the constructs which can be generated. In this study, a highly extensible bioink system created by modulating the rheology of physically crosslinked hydrogels comprising hydrophobically-modified cellulosics and either surfactants or cyclodextrins is reported. It is demonstrated that these hydrogels are highly shear-thinning with broadly tunable viscoelasticity and stress-relaxation through simple modulation of the composition. Rheological experiments demonstrate that increasing concentration of rheology-modifying additives yields hydrogel materials exhibiting extensional strain-to-break values up to 2000%, which is amongst the most extensible examples of physically crosslinked hydrogels of this type. The potential of these hydrogels for use as bioinks is demonstrated by evaluating the relationship between extensibility and printability, demonstrating that greater hydrogel extensibility enables faster print speeds and smaller print features. The findings suggest that optimizing hydrogel extensibility can enhance high-speed 3D bioprinting capabilities, reporting over 5000 fold enhancement in speed index compared to existing works reported for hydrogel-based bioinks in extrusion-based printing.

Improved Efficacy of Triple-Negative Breast Cancer Immunotherapy via Hydrogel-Based Co-Delivery of CAR-T Cells and Mitophagy Agonist

Leaky and structurally abnormal blood vessels and increased pressure in the tumor interstitium reduce the infiltration of CAR-T cells in solid tumors, including triple-negative breast cancer (TNBC). Furthermore, high burden of tumor cells may cause reduction of infiltrating CAR-T cells and their functional exhaustion. In this study, various effector-to-target (E:T) ratio experiments are established to model the treatment using CAR-T cells in leukemia (high E:T ratio) and solid tumor (low E:T ratio). It is found that the antitumor immune response is decreased in solid tumors with low E:T ratio. Furthermore, single cell sequencing is performed to investigate the functional exhaustion at a low ratio. It is revealed that the inhibition of mitophagy-mediated mitochondrial dysfunction diminished the antitumor efficacy of CAR-T-cell therapy. The mitophagy agonist BC1618 is screened via AI-deep learning and cytokine detection, in vivo and in vitro studies revealed that BC1618 significantly strengthened the antitumor response of CAR-T cells via improving mitophagy. Here, injection hydrogels are engineered for the controlled co-delivery of CAR-T cells and BC1618 that improves the treatment of TNBC. Local delivery of hydrogels creates an inflammatory and mitophagy-enhanced microenvironment at the tumor site, which stimulates the CAR-T cells proliferation, provides antitumor ability persistently, and improves the effect of treatment.

CAR-T therapy dilemma and innovative design strategies for next generation

Chimeric antigen receptor (CAR)-T-cell therapy has shown remarkable curative effects on hematological tumors, driving the exponential growth in CAR-T-related research. Although CD19-targeting CAR-T-cell therapy has displayed remarkable promise in clinical trials, many obstacles are arising that limit its therapeutic efficacy in tumor immunotherapy. The "dilemma" of CAR-T cell-based tumor therapy includes lethal cytotoxicity, restricted trafficking, limited tumor infiltration, an immunosuppressive microenvironment, immune resistance and limited potency. The solution to CAR-T-cell therapy's dilemma requires interdisciplinary strategies, including synthetic biology-based ON/OFF switch, bioinstructive scaffolds, nanomaterials, oncolytic viruses, CRISPR screening, intestinal microbiota and its metabolites. In this review, we will introduce and summarize these interdisciplinary-based innovative technologies for the next generation CAR-T-cell design and delivery to overcome the key barriers of current CAR-T cells.

Osteopontin attenuates the foreign-body response to silicone implants

The inflammatory process resulting in the fibrotic encapsulation of implants has been well studied. However, how acellular dermal matrix (ADM) used in breast reconstruction elicits an attenuated foreign-body response (FBR) remains unclear. Here, by leveraging single-cell RNA-sequencing and proteomic data from pairs of fibrotically encapsulated specimens (bare silicone and silicone wrapped with ADM) collected from individuals undergoing breast reconstruction, we show that high levels of the extracellular-matrix protein osteopontin are associated with the use of ADM as a silicone wrapping. In mice with osteopontin knocked out, FBR attenuation by ADM-coated implants was abrogated. In wild-type mice, the sustained release of recombinant osteopontin from a hydrogel placed adjacent to a silicone implant attenuated the FBR in the absence of ADM. Our findings suggest strategies for the further minimization of the FBR.

Sustained Vaccine Exposure Elicits More Rapid, Consistent, and Broad Humoral Immune Responses to Multivalent Influenza Vaccines

With the ever-present threat of pandemics, it is imperative vaccine technologies eliciting broad and durable immunity to high-risk pathogens are developed. Yet, current annual influenza vaccines, for example, fail to provide robust immunity against the 3-4 homologous strains they contain, let alone heterologous strains. Herein, this study demonstrates that sustained delivery of multivalent influenza vaccines from an injectable polymer-nanoparticle (PNP) hydrogel technology induces more rapid, consistent, and potent humoral immune responses against multiple homologous viruses, as well as potent responses against heterologous viruses and potential pandemic subtypes H5N1, H7N9 and H9N2. Further, admixing PNP hydrogels with commercial influenza vaccines results in stronger hemagglutination inhibition against both heterologous and homologous viruses. Additional investigation shows this enhanced potency and breadth arise from higher affinity antibodies targeting both the hemagglutinin stem and head. Overall, this simple and effective sustained delivery platform for multivalent annual influenza vaccines generates durable, potent, and remarkably broad immunity to influenza.

Harnessing phytochemicals: Innovative strategies to enhance cancer immunotherapy

Cancer immunotherapy has revolutionized cancer treatment, but therapeutic ineffectiveness-driven by the tumor microenvironment and immune evasion mechanisms-continues to limit its clinical efficacy. This challenge underscores the need to explore innovative approaches, such as multimodal immunotherapy. Phytochemicals, bioactive compounds derived from plants, have emerged as promising candidates for overcoming these barriers due to their immunomodulatory and antitumor properties. This review explores the synergistic potential of phytochemicals in enhancing immunotherapy by modulating immune responses, reprogramming the tumor microenvironment, and reducing immunosuppressive factors. Integrating phytochemicals with conventional immunotherapy strategies represents a novel approach to mitigating resistance and enhancing therapeutic outcomes. For instance, nab-paclitaxel has shown the potential in overcoming resistance to immune checkpoint inhibitors, while QS-21 synergistically enhances the efficacy of tumor vaccines. Furthermore, we highlight recent advancements in leveraging nanotechnology to engineer phytochemicals for improved bioavailability and targeted delivery. These innovations hold great promise for optimizing the clinical application of phytochemicals. However, further large-scale clinical studies are crucial to fully integrate these compounds into immunotherapeutic regimens effectively.

A thiol-ene click-based strategy to customize injectable polymer-nanoparticle hydrogel properties for therapeutic delivery

Polymer-nanoparticle (PNP) hydrogels are a promising injectable biomaterial platform that has been used for a wide range of biomedical applications including adhesion prevention, adoptive cell delivery, and controlled drug release. By tuning the chemical, mechanical, and erosion properties of injected hydrogel depots, additional control over cell compatibility and pharmaceutical release kinetics may be realized. Here, we employ thiol-ene click chemistry to prepare a library of modified hydroxypropylmethylcellulose (HPMC) derivatives for subsequent use in PNP hydrogel applications. When combined with poly(ethylene glycol)-b-poly(lactic acid) nanoparticles, we demonstrate that systematically altering the hydrophobic, steric, or pi stacking character of HPMC modifications can readily tailor the mechanical properties of PNP hydrogels. Additionally, we highlight the compatibility of the synthetic platform for the incorporation of cysteine-bearing peptides to access PNP hydrogels with improved bioactivity. Finally, through leveraging the tunable physical properties afforded by this method, we show hydrogel retention time in vivo can be dramatically altered without sacrificing mesh size or cargo diffusion rates. This work offers a route to optimize PNP hydrogels for a variety of translational applications and holds promise in the highly tunable delivery of pharmaceuticals and adoptive cells.

Recent Advances in Polysaccharide-Based Hydrogels for Tumor Immunotherapy

Immunotherapy has revolutionized cancer treatment and led to a significant increase in patient survival rates and quality of life. However, the effectiveness of current immunotherapies is limited by various factors, including immune evasion mechanisms and serious side effects. Hydrogels are a type of medical material with an ideal biocompatibility, variable structure, flexible synthesis method, and physical properties. Hydrogels have long been recognized and used as a superior choice for various biomedical applications. The fascinating results were derived from both in vitro and in vivo models. The rapid expansion of this area suggests that the principles and uses of functionalized polysaccharides are transformative, motivating researchers to investigate novel polysaccharide-based hydrogels for wider applications. Polysaccharide hydrogels have proven to be a practicable delivery strategy for tumor immunotherapy due to their biocompatibility, biodegradability, and pronounced bioactive characteristics. This study aims to examine in detail the latest developments of polysaccharide hydrogels in tumor immunotherapy, focusing on their design, mechanism of action, and potential therapeutic applications.

Chimeric Antigen Receptor Cells Solid Tumor Immunotherapy Assisted by Biomaterials Tools

Chimeric antigen receptor (CAR) immune cell therapies have revolutionized oncology, particularly in hematological malignancies, yet their efficacy against solid tumors remains limited due to challenges such as dense stromal barriers and immunosuppressive microenvironments. With advancements in nanobiotechnology, researchers have developed various strategies and methods to enhance the CAR cell efficacy in solid tumor treatment. In this Review, we first outline the structure and mechanism of CAR-T (T, T cell), CAR-NK (NK, natural killer), and CAR-M (M, macrophage) cell therapies and deeply analyze the potential of these cells in the treatment of solid tumors and the challenges they face. Next, we explore how biomaterials can optimize these treatments by improving the tumor microenvironment, controlling CAR cell release, promoting cell infiltration, and enhancing efficacy. Finally, we summarize the current challenges and potential solutions, emphasize the effective combination of biomaterials and CAR cell therapy, and look forward to its future clinical application and treatment strategies. This Review provides important theoretical perspectives and practical guidance for the future development of more effective solid tumor treatment strategies.

Targeted and precise drug delivery using a glutathione-responsive ultra-short peptide-based injectable hydrogel as a breast cancer cure

Harnessing the potential of hydrogel-based localized drug delivery systems holds immense promise for mitigating the systemic side effects associated with conventional cancer therapies. However, the development of such systems demands the fulfillment of multiple stringent criteria, including injectability, biocompatibility, and controlled release. Herein, we present an ultra-small peptide-based hydrogel for the sustained and targeted delivery of doxorubicin in a murine model of breast cancer. The hydrogel evades dissolution and remains stable in biological fluids, serving as a reliable drug reservoir. However, it specifically reacts to the high levels of glutathione (GSH) in the tumor microenvironment and releases drugs in a controlled manner over time for consistent therapeutic benefits. Remarkably, administration of a single dose of doxorubicin-loaded hydrogel elicited superior tumor regression (approximately 75% within 18 days) compared to conventional doxorubicin treatment alone. Furthermore, the persistent presence of the drug-loaded hydrogel near the tumor site for up to 18 days after administration highlights its enduring effectiveness. There is great clinical potential for this localized delivery strategy because of the minimal off-target effects on healthy tissues. Our findings underscore the efficacy of this smart peptide-hydrogel platform and pave the way for developing next-generation localized drug delivery systems with enhanced therapeutic outcomes in cancer treatment.

Biomaterial-Based Therapeutic Delivery of Immune Cells

Immune cell therapy (ICT) is a transformative approach used to treat a wide range of diseases including type 1 diabetes, sickle cell disease, disorders of the hematopoietic system, and certain forms of cancers. Despite excellent clinical successes, the scope of adoptively transferred immune cells is limited because of toxicities like cytokine release syndrome and immune effector cell-associated neurotoxicity in patients. Furthermore, reports suggest that such treatment can impact major organ systems including cardiac, renal, pulmonary, and hepatic systems in the long term. Additionally, adoptively transferred immune cells cannot achieve significant penetration into solid tissues, thus limiting their therapeutic potential. Recent studies suggest that biomaterial-assisted delivery of immune cells can address these challenges by reducing toxicity, improving localization, and maintaining desired phenotypes to eventually regain tissue function. In this review, recent efforts in the field of biomaterial-based immune cell delivery for the treatment of diseases, their pros and cons, and where these approaches stand in terms of clinical treatment are highlighted.

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.

Linking structural and rheological memory in disordered soft materials

Linking the macroscopic flow properties and nanoscopic structure is a fundamental challenge to understanding, predicting, and designing disordered soft materials. Under small stresses, these materials are soft solids, while larger loads can lead to yielding and the acquisition of plastic strain, which adds complexity to the task. In this work, we connect the transient structure and rheological memory of a colloidal gel under cyclic shearing across a range of amplitudes via a generalized memory function using rheo-X-ray photon correlation spectroscopy (rheo-XPCS). Our rheo-XPCS data show that the nanometer scale aggregate-level structure recorrelates whenever the change in recoverable strain over some interval is zero. The macroscopic recoverable strain is therefore a measure of the nano-scale structural memory. We further show that yielding in disordered colloidal materials is strongly heterogeneous and that memories of prior deformation can exist even after the material has been subjected to flow.

Fluorescein-based SynNotch adaptors for regulating gene expression responses to diverse extracellular and matrix-based cues

Synthetic Notch (SynNotch) receptors function like natural Notch proteins and can be used to install customized sense-and-respond capabilities into mammalian cells. Here, we introduce an adaptor-based strategy for regulating SynNotch activity via fluorescein isomers and analogs. Using an optimized fluorescein-binding SynNotch receptor, we describe ways to chemically control SynNotch signaling, including an approach based on a bio-orthogonal chemical ligation and a spatially controllable strategy via the photo-patterned uncaging of an o-nitrobenzyl-caged fluorescein conjugate. We further show that fluorescein-conjugated extracellular matrix (ECM)-binding peptides can be used to regulate SynNotch activity depending on the folding state of collagen-based ECM networks. To demonstrate the utility of these tools, we apply them to activate dose-dependent gene expression responses and to induce myogenic-like phenotypes in multipotent fibroblasts with spatiotemporal and microenvironmental control. Overall, we introduce an optimized fluorescein-binding SynNotch as a versatile tool for regulating transcriptional responses to ligands based on the clinically-approved fluorescein dye.

Intrinsic immunomodulatory hydrogels for chronic inflammation

The immune system plays a pivotal role in maintaining physiological homeostasis and influencing disease processes. Dysregulated immune responses drive chronic inflammation, which in turn results in a range of diseases that are among the leading causes of death globally. Traditional immune interventions, which aim to regulate either insufficient or excessive inflammation, frequently entail lifelong comorbidities and the risk of severe side effects. In this context, intrinsic immunomodulatory hydrogels, designed to precisely control the local immune microenvironment, have recently attracted increasing attention. In particular, these advanced hydrogels not only function as delivery mechanisms but also actively engage in immune modulation, optimizing interactions with the immune system for enhanced tissue repair, thereby providing a sophisticated strategy for managing chronic inflammation. In this tutorial review, we outline key elements of chronic inflammation and subsequently explore the strategic design principles of intrinsic immunomodulatory hydrogels based on these elements. Finally, we examine the challenges and prospects of such immunomodulatory hydrogels, which are expected to inspire further preclinical research and clinical translation in addressing chronic inflammation.

Unlocking the Potential of Hybrid Nanocomposite Hydrogels: Design, Mechanical Properties and Biomedical Performances

Hybrid nanocomposite hydrogels consist of the homogeneous incorporation of nano‐objects in a hydrogel matrix. The latter, whether made of natural or synthetic materials, possesses a microporous, soft structure that makes it an ideal host for a variety of polymer and lipid‐based nano‐objects as well as metal‐ and silica‐based ones. By carefully choosing the composition and the proportions of the different constituents, hybrid hydrogels can display a wide array of properties, from simple enhancement of mechanical characteristics to specific bioactivity. This review aims to provide an overview of the state of the art in hybrid hydrogels highlighting key aspects that make them a promising choice for a variety of biomedical applications. Strategies for the preparation of hybrid hydrogels are discussed by covering the selection of individual components. The review will also explore the physico‐chemical and rheological characterization of these materials, which is essential for understanding their structure and function, ultimately satisfying specifications for the intended use. Successful examples of biomedical applications will also be presented, and the main challenges to be met will be discussed, with the aim of stimulating the research community to exploit the full potential of these materials.

Optimising CAR T therapy for the treatment of solid tumors

INTRODUCTION

Adoptive immunotherapy using chimeric antigen receptor (CAR)-engineered T cells has proven transformative in the management of B cell and plasma cel derived malignancies. However, solid tumors have largely proven to be resistant to this therapeutic modality. Challenges include the paucity of safe target antigens, heterogeneity of target expression within the tumor, difficulty in delivery of CAR T cells to the site of disease, poor penetration within solid tumor deposits and inability to circumvent the array of immunosuppressive and biophysical barriers imposed by the solid tumor microenvironment.

AREAS COVERED

Literature was reviewed on the PubMed database, excluding occasional papers which were not available as open access publications or through other means.

EXPERT OPINION

Here, we have surveyed the large body of technological advances that have been made in the quest to bridge the gap toward successful deployment of CAR T cells for the treatment of solid tumors. These encompass the development of more sophisticated targeting strategies to engage solid tumor cells safely and comprehensively, improved drug delivery solutions, design of novel CAR architectures that achieve improved functional persistence and which resist physical, chemical and biological hurdles present in tumor deposits. Prospects for combination therapies that incorporate CAR T cells are also considered.

Developing CAR T-Cell Therapies for Pediatric Solid Tumors

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of hematological malignancies, inducing notable and durable clinical responses. However, for solid tumors, including but not limited to pediatric tumors, several peculiar biological features posed substantial challenges for achieving comparable results. Despite sound pre-clinical evidence of the ability of CAR T cells to eradicate solid malignancies, their activity remains suboptimal when facing the in vivo complexity of solid tumors, characterized by antigen heterogeneity, scarce T-cell infiltration, and an immunosuppressive microenvironment. Neuroblastoma was amongst the first tumors to be evaluated as a potential candidate for GD2-targeting CAR T cells, which recently documented promising results in high-risk, heavily pre-treated patients. Moreover, innovative engineering strategies for generating more potent and persistent CAR T cells suggest the possibility to reproduce, and potentially improve, these promising results on a larger scale. In the next years, harnessing the full therapeutic potential of CAR T cells and other immunotherapeutic strategies may open new possibilities for effectively treating the most aggressive forms of pediatric tumors.

Bioactive nanocomposite hydrogel enhances postoperative immunotherapy and bone reconstruction for osteosarcoma treatment

Osteosarcoma, a malignant bone tumor often characterized by high hedgehog signaling activity, residual tumor cells, and substantial bone defects, poses significant challenges to both treatment response and postsurgical recovery. Here, we developed a nanocomposite hydrogel for the sustained co-delivery of bioactive magnesium ions, anti-PD-L1 antibody (αPD-L1), and hedgehog pathway antagonist vismodegib, to eradicate residual tumor cells while promoting bone regeneration post-surgery. In a mouse model of tibia osteosarcoma, this hydrogel-mediated combination therapy led to remarkable tumor growth inhibition and hence increased animal survival by enhancing the activity of tumor-suppressed CD8+ T cells. Meanwhile, the implanted hydrogel improved the microenvironment of osteogenesis through long-term sustained release of Mg2+, facilitating bone defect repair by upregulating the expression of osteogenic genes. After 21 days, the expression levels of ALP, COL1, RUNX2, and BGLAP in the Vis-αPD-L1-Gel group were approximately 4.1, 5.1, 5.5, and 3.4 times higher than those of the control, respectively. We believe that this hydrogel-based combination therapy offers a potentially valuable strategy for treating osteosarcoma and addressing the tumor-related complex bone diseases.

Generation of an inflammatory niche in an injectable hydrogel depot through recruitment of key immune cells improves efficacy of mRNA vaccines

Messenger RNA (mRNA) delivered in lipid nanoparticles (LNPs) rose to the forefront of vaccine candidates during the COVID-19 pandemic due in part to scalability, adaptability, and potency. Yet there remain critical areas for improvements of these vaccines in durability and breadth of humoral responses. In this work, we explore a modular strategy to target mRNA/LNPs to antigen presenting cells with an injectable polymer-nanoparticle (PNP) hydrogel depot technology which recruits key immune cells and forms an immunological niche in vivo. We characterize this niche on a single cell level and find it is highly tunable through incorporation of adjuvants like MPLAs and 3M-052. Delivering commercially available SARS-CoV-2 mRNA vaccines in PNP hydrogels improves the durability and quality of germinal center reactions, and the magnitude, breadth, and durability of humoral responses. The tunable immune niche formed within PNP hydrogels effectively skews immune responses based on encapsulated adjuvants, creating opportunities to precisely modulate mRNA/LNP vaccines for various indications from infectious diseases to cancers.

CAR T cells in solid tumors and metastasis: paving the way forward

CAR T cell therapy, hailed as a breakthrough in cancer treatment due to its remarkable outcomes in hematological malignancies, encounters significant hurdles when applied to solid tumors. While notable responses to CAR T cells remain sporadic in these patients, challenges persist due to issues such as on-target off-tumor toxicity, difficulties in their trafficking and infiltration into the tumor, and the presence of a hostile and immunosuppressive microenvironment. This review aims to explore recent endeavors aimed at overcoming these obstacles in CAR T cell therapy for solid tumors. Specifically, we will delve into promising strategies for enhancing tumor specificity through antigen targeting, addressing tumor heterogeneity, overcoming physical barriers, and counteracting the immune-suppressive microenvironment.

In vivo gene editing of T-cells in lymph nodes for enhanced cancer immunotherapy

Immune checkpoint blockade (ICB) therapy, while promising for cancer treatment, faces challenges like unexpected side effects and limited objective responses. Here, we develop an in vivo gene-editing strategy for improving ICB cancer therapy in a lastingly effective manner. The approach uses a conductive hydrogel-based electroporation system to enable nucleofection of programmed cell death protein 1 (PD1) targeted CRISPR-Cas9 DNAs into T-cells directly within the lymph nodes, and subsequently produces PD1-deficient T-cells to combat tumor growth, metastasis and recurrence in different melanoma models in mice. Following in vivo gene editing, animals show enhanced cellular and humoral immune responses along with multi-fold increases of effector T-cells infiltration to the solid tumors, preventing tumor recurrence and prolonging their survival. These findings provide a proof-of-concept for direct in vivo T-cell engineering via localized gene-editing for enhanced cancer immunotherapy, and also unlock the possibilities of using this method to treat more complex human diseases.

Biomaterial-Mediated Metabolic Regulation of Ferroptosis for Cancer Immunotherapy

Ferroptosis is a lipid peroxidation-driven cell death route and has attracted enormous interest for cancer therapy. Distinct from other forms of regulated cell death, its process is involved with multiple metabolic pathways including lipids, bioenergetics, iron, and so on, which influence cancer cell ferroptosis sensitivity and communication with the immune cells in the tumor microenvironment. Development of novel technologies for harnessing the ferroptosis-associated metabolic regulatory network would profoundly improve our understanding of the immune responses and enhance the efficacy of ferroptosis-dependent immunotherapy. Interestingly, the recent advances in bio-derived material-based therapeutic platforms offer novel opportunities to therapeutically modulate tumor metabolism through the in situ delivery of molecular or material cues, which not only allows the tumor-specific elicitation of ferroptosis but also holds promise to maximize their immunostimulatory impact. In this review, we will first dissect the crosstalk between tumor metabolism and ferroptosis and its impact on the immune regulation in the tumor microenvironment, followed by the comprehensive analysis on the recent progress in biomaterial-based metabolic regulatory strategies for evoking ferroptosis-mediated antitumor immunity. A perspective section is also provided to discuss the challenges in metabolism-regulating biomaterials for ferroptosis-immunotherapy. We envision that this review may provide new insights for improving tumor immunotherapeutic efficacy in the clinic.

Biomedical Applications and Nutritional Value of Specific Food-Derived Polysaccharide-Based Hydrogels

Food-derived polysaccharide-based hydrogels (FPBHs), which are composed of polysaccharides derived from food sources exhibit great potential for biomedical applications. The FPBHs possess a wide range of biological activities and can be utilized in the treatment of various clinical diseases. However, the majority of research efforts have predominantly focused on nonspecific polysaccharides derived from various sources (most plants, animals, and microorganisms), whereas the exploration of hydrogels originating from specific polysaccharides with distinct bioactivity extracted from natural food sources remains limited. In this review, a comprehensive search was conducted across 3 major databases (PubMed, Web of Science, and Medline) until October 24, 2024 to include 32 studies that employed FPBHs for biomedical applications. This review provides an overview of hydrogels based on specific food-derived polysaccharides by summarizing their types, sources, molecular weight, monosaccharide composition, and biological activities. The crosslinking strategies employed in the fabrication of FPBHs were demonstrated. The attributes and characteristics of FPBHs were delined, including their physical, chemical, and functional properties. Of particular note, the review highlights in vivo and in vitro studies exploring the biomedical applications of FPBHs and delve into the nutritional value of specific food-derived polysaccharides. The challenges encountered in basic research involving FPBHs were enumerated as well as limitation in their clinical practice. Finally, the potential market outlook for FPBHs in the future was also discussed.

Intelligent Hydrogel-Assisted Hepatocellular Carcinoma Therapy

Given the high malignancy of liver cancer and the liver's unique role in immune and metabolic regulation, current treatments have limited efficacy, resulting in a poor prognosis. Hydrogels, soft 3-dimensional network materials comprising numerous hydrophilic monomers, have considerable potential as intelligent drug delivery systems for liver cancer treatment. The advantages of hydrogels include their versatile delivery modalities, precision targeting, intelligent stimulus response, controlled drug release, high drug loading capacity, excellent slow-release capabilities, and substantial potential as carriers of bioactive molecules. This review presents an in-depth examination of hydrogel-assisted advanced therapies for hepatocellular carcinoma, encompassing small-molecule drug therapy, immunotherapy, gene therapy, and the utilization of other biologics. Furthermore, it examines the integration of hydrogels with conventional liver cancer therapies, including radiation, interventional therapy, and ultrasound. This review provides a comprehensive overview of the numerous advantages of hydrogels and their potential to enhance therapeutic efficacy, targeting, and drug delivery safety. In conclusion, this review addresses the clinical implementation of hydrogels in liver cancer therapy and future challenges and design principles for hydrogel-based systems, and proposes novel research directions and strategies.

Water-Enhancing Gels Exhibiting Heat-Activated Formation of Silica Aerogels for Protection of Critical Infrastructure During Catastrophic Wildfire

A promising strategy to address the pressing challenges with wildfire, particularly in the wildland-urban interface (WUI), involves developing new approaches for preventing and controlling wildfire within wildlands. Among sprayable fire-retardant materials, water-enhancing gels have emerged as exceptionally effective for protecting civil infrastructure. They possess favorable wetting and viscoelastic properties that reduce the likelihood of ignition, maintaining strong adherence to a wide array of surfaces after application. Although current water-enhancing hydrogels effectively maintain surface wetness by creating a barricade, they rapidly desiccate and lose efficacy under high heat and wind typical of wildfire conditions. To address this limitation, unique biomimetic hydrogel materials from sustainable cellulosic polymers crosslinked by colloidal silica particles are developed that exhibit ideal viscoelastic properties and facile manufacturing. Under heat activation, the hydrogel transitions into a highly porous and thermally insulative silica aerogel coating in situ, providing a robust protective layer against ignition of substrates, even when the hydrogel fire suppressant becomes completely desiccated. By confirming the mechanical properties, substrate adherence, and enhanced substrate protection against fire, these heat-activatable biomimetic hydrogels emerge as promising candidates for next-generation water-enhancing fire suppressants. These advancements have the potential to dramatically improve the ability to protect homes and critical infrastructure during wildfire.

Delivery Systems Developed for Treatment Combinations to Improve Adoptive Cell Therapy

Adoptive cell therapy (ACT) has shown great success in the clinic for treating hematologic malignancies. However, solid tumor treatment with ACT monotherapy is still challenging, owing to insufficient expansion and rapid exhaustion of adoptive cells, tumor antigen downregulation/loss, and dense tumor extracellular matrix. Delivery strategies for combination cell therapy have great potential to overcome these hurdles. The delivery of vaccines, immune checkpoint inhibitors, cytokines, chemotherapeutics, and photothermal reagents in combination with adoptive cells, have been shown to improve the expansion/activation, decrease exhaustion, and promote the penetration of adoptive cells in solid tumors. Moreover, the delivery of nucleic acids to engineer immune cells directly in vivo holds promise to overcome many of the hurdles associated with the complex ex vivo cell engineering strategies. Here, these research advance, as well as the opportunities and challenges for integrating delivery technologies into cell therapy s are discussed, and the outlook for these emerging areas are criticlly analyzed.

DeltaRex-G, tumor targeted retrovector encoding a CCNG1 inhibitor, for CAR-T cell therapy induced cytokine release syndrome

Cytokine release syndrome is a serious complication of chimeric antigen receptor-T cell therapy and is triggered by excessive secretion of inflammatory cytokines by chimeric T cells which could be fatal. Following an inquiry into the molecular mechanisms orchestrating cytokine release syndrome, we hypothesize that DeltaRex-G, a tumor targeted retrovector encoding a cytocidal CCNG1 inhibitor gene, may be a viable treatment option for corticosteroid-resistant cytokine release syndrome. DeltaRex-G received United States Food and Drug Administration Emergency Use Authorization to treat Covid-19-induced acute respiratory distress syndrome, which is due to hyperactivated immune cells. A brief administration of DeltaRex-G would inhibit a certain proportion of hyperactive chimeric T cells, consequently reducing cytokine release while retaining chimeric T cell efficacy.

ReCARving the future: bridging CAR T-cell therapy gaps with synthetic biology, engineering, and economic insights

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematologic malignancies, offering remarkable remission rates in otherwise refractory conditions. However, its expansion into broader oncological applications faces significant hurdles, including limited efficacy in solid tumors, safety concerns related to toxicity, and logistical challenges in manufacturing and scalability. This review critically examines the latest advancements aimed at overcoming these obstacles, highlighting innovations in CAR T-cell engineering, novel antigen targeting strategies, and improvements in delivery and persistence within the tumor microenvironment. We also discuss the development of allogeneic CAR T cells as off-the-shelf therapies, strategies to mitigate adverse effects, and the integration of CAR T cells with other therapeutic modalities. This comprehensive analysis underscores the synergistic potential of these strategies to enhance the safety, efficacy, and accessibility of CAR T-cell therapies, providing a forward-looking perspective on their evolutionary trajectory in cancer treatment.

In vivo manufacture and manipulation of CAR-T cells for better druggability

The current CAR-T cell therapy products have been hampered in their druggability due to the personalized preparation required, unclear pharmacokinetic characteristics, and unpredictable adverse reactions. Enabling standardized manufacturing and having clear efficacy and pharmacokinetic characteristics are prerequisites for ensuring the effective practicality of CAR-T cell therapy drugs. This review provides a broad overview of the different approaches for controlling behaviors of CAR-T cells in vivo. The utilization of genetically modified vectors enables in vivo production of CAR-T cells, thereby abbreviating or skipping the lengthy in vitro expansion process. By equipping CAR-T cells with intricately designed control elements, using molecule switches or small-molecule inhibitors, the control of CAR-T cell activity can be achieved. Moreover, the on-off control of CAR-T cell activity would yield potential gains in phenotypic remodeling. These methods provide beneficial references for the future development of safe, controllable, convenient, and suitable for standardized production of CAR-T cell therapy products.

CAR T cell infiltration and cytotoxic killing within the core of 3D breast cancer spheroids under the control of antigen sensing in microwell arrays

The success of chimeric antigen receptor (CAR) T cells in blood cancers has intensified efforts to develop CAR T therapies for solid cancers. In the solid tumor microenvironment, CAR T cell trafficking and suppression of cytotoxic killing represent limiting factors for therapeutic efficacy. Here, we present a microwell platform to study CAR T cell interactions with 3D breast tumor spheroids and determine predictors of anti-tumor CAR T cell function. To precisely control antigen sensing, we utilized a switchable adaptor CAR system that covalently attaches to co-administered antibody adaptors and mediates antigen recognition. Following the addition of an anti-HER2 adaptor antibody, primary human CAR T cells exhibited higher infiltration, clustering, and secretion of effector cytokines. By tracking CAR T cell killing in individual spheroids, we showed the suppressive effects of spheroid size and identified the initial CAR T cell to spheroid area ratio as a predictor of cytotoxicity. We demonstrate that larger spheroids exhibit higher hypoxia levels and are infiltrated by CAR T cells with a suppressed activation state, characterized by reduced expression of IFN-γ, TNF-α, and granzyme B. Spatiotemporal analysis revealed lower CAR T cell numbers and cytotoxicity in the spheroid core compared to the periphery. Finally, increasing CAR T cell seeding density resulted in higher CAR T cell infiltration and cancer cell elimination in the spheroid core. Our findings provide new quantitative insight into CAR T cell function within 3D cancer spheroids. Given its miniaturized nature and live imaging capabilities, our microfabricated system holds promise for screening cellular immunotherapies.

Saponin nanoparticle adjuvants incorporating Toll-like receptor agonists drive distinct immune signatures and potent vaccine responses

Over the past few decades, the development of potent and safe immune-activating adjuvant technologies has become the heart of intensive research in the constant fight against highly mutative and immune evasive viruses such as influenza, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and human immunodeficiency virus (HIV). Herein, we developed a highly modular saponin-based nanoparticle platform incorporating Toll-like receptor agonists (TLRas) including TLR1/2a, TLR4a, and TLR7/8a adjuvants and their mixtures. These various TLRa-saponin nanoparticle adjuvant constructs induce unique acute cytokine and immune-signaling profiles, leading to specific T helper responses that could be of interest depending on the target disease for prevention. In a murine vaccine study, the adjuvants greatly improved the potency, durability, breadth, and neutralization of both COVID-19 and HIV vaccine candidates, suggesting the potential broad application of these adjuvant constructs to a range of different antigens. Overall, this work demonstrates a modular TLRa-SNP adjuvant platform that could improve the design of vaccines and affect modern vaccine development.

Advanced strategies in improving the immunotherapeutic effect of CAR-T cell therapy

Chimeric antigen receptor (CAR-T) cell therapy is a newly developed immunotherapy strategy and has achieved satisfactory outcomes in the treatment of hematological malignancies. However, some adverse effects related to CAR-T cell therapy have to be resolved before it is widely used in clinics as a cancer treatment. Furthermore, the application of CAR-T cell therapy in the treatment of solid tumors has been hampered by numerous limitations. Therefore, it is essential to explore novel strategies to improve the therapeutic effect of CAR-T cell therapy. In this review, we summarized the recently developed strategies aimed at optimizing the generation of CAR-T cells and improving the anti-tumor efficiency of CAR-T cell therapy. Furthermore, the discovery of new targets for CAR-T cell therapy and the combined treatment strategies of CAR-T cell therapy with chemotherapy, radiotherapy, cancer vaccines and nanomaterials are highlighted.

Recent advancements of hydrogels in immunotherapy: Breast cancer treatment

Breast cancer is the most prevalent cancer among women and the leading cause of cancer-related deaths in this population. Recent advances in Immunotherapy, or combined immunotherapy, offering a more targeted and less toxic approach, expand the survival rate of patients more than conventional treatment. Notably, hydrogels, a versatile platform provided promising avenues to combat breast cancer in preclinical studies and extended to clinical practices. With advantages such as the alternation of tumor microenvironment, immunomodulation, targeted delivery of therapeutic agents, and their sustained release at specific sites of interest, hydrogels can potentially be used for the treatment of breast cancer. This review highlights the advantages, mechanisms of action, stimuli-responsiveness properties, and recent advancements of hydrogels for treating breast cancer immunotherapy. Moreover, post-treatment and its clinical translations are discussed in this review. The integration of hydrogels in immunotherapy strategies may pave the way for more effective, personalized, and patient-friendly approaches to combat breast cancer, ultimately contributing to a brighter future for breast cancer patients.

Infusion and delivery strategies to maximize the efficacy of CAR-T cell immunotherapy for cancers

Chimeric antigen receptor (CAR) T-cell therapy has achieved substantial clinical outcomes for tumors, especially for hematological malignancies. However, extending the duration of remission, reduction of relapse for hematological malignancies and improvement of the anti-tumor efficacy for solid tumors are challenges for CAR-T cells immunotherapy. Besides the endeavors to enhance the functionality of CAR-T cell per se, optimization of the infusion and delivery strategies facilitates the breakthrough of the hurdles that limited the efficacy of this cancer immunotherapy. Here, we summarized the infusion and delivery strategies of CAR-T cell therapies under pre-clinical study, clinical trials and on-market status, through which the improvements of safety and efficacy for hematological and solid tumors were analyzed. Of note, novel infusion and delivery strategies, including local-regional infusion, biomaterials bearing the CAR-T cells and multiple infusion technique, overcome many limitations of CAR-T cell therapy. This review provides hints to determine infusion and delivery strategies of CAR-T cell cancer immunotherapy to maximize clinical benefits.

Recent Advancements in Biomaterials for Chimeric Antigen Receptor T Cell Immunotherapy

Cellular immunotherapy is an innovative cancer treatment method that utilizes the patient's own immune system to combat tumor cells effectively. Currently, the mainstream therapeutic approaches include chimeric antigen receptor T cell (CAR-T) therapy, T cell receptor gene-modified T cell therapy and chimeric antigen receptor natural killer-cell therapy with CAR-T therapy mostly advanced. Nonetheless, the conventional manufacturing process of this therapy has shortcomings in each step that call for improvement. Marked efforts have been invested for its enhancement while notable progresses achieved in the realm of biomaterials application. With CAR-T therapy as a prime example, the aim of this review is to comprehensively discuss the various biomaterials used in cell immunotherapy, their roles in regulating immune cells, and their potential for breakthroughs in cancer treatment from gene transduction to efficacy enhancement. This article additionally addressed widely adopted animal models for efficacy evaluating.

Hydrogel Encapsulation Techniques and Its Clinical Applications in Drug Delivery and Regenerative Medicine: A Systematic Review

Hydrogel encapsulation is a promising carrier for cell and drug delivery due to its ability to protect the encapsulated entities from harsh physiological conditions and enhance their therapeutic efficacy and bioavailability. However, there is not yet consensus on the optimal hydrogel type, encapsulation method, and clinical application. Therefore, a systematic review of hydrogel encapsulation techniques and their potential for clinical application is needed to provide a comprehensive and up-to-date overview. In this systematic review, we searched electronic databases for articles published between 2008 and 2023 that described the encapsulation of cells or drug molecules within hydrogels. Herein, we identified 9 relevant studies that met the inclusion and exclusion criteria of our study. Our analysis revealed that the physicochemical properties of the hydrogel, such as its porosity, swelling behavior, and degradation rate, play a critical role in the encapsulation of cells or drug molecules. Furthermore, the encapsulation method, including physical, chemical, or biological methods, can affect the encapsulated entities' stability, bioavailability, and therapeutic efficacy. Challenges of hydrogel encapsulation include poor control over the release of encapsulated entities, limited shelf life, and potential immune responses. Future directions of hydrogel encapsulation include the development of novel hydrogel and encapsulation methods and the integration of hydrogel encapsulation with other technologies, such as 3D printing and gene editing. In conclusion, this review is useful for researchers, clinicians, and policymakers who are interested in this field of drug delivery and regenerative medicine that can serve as a guide for the future development of novel technologies that can be applied into clinical practice.

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.

Injectable Hydrogels: A Paradigm Tailored with Design, Characterization, and Multifaceted Approaches

Biomaterials denoting self-healing and versatile structural integrity are highly curious in the biomedicine segment. The injectable and/or printable 3D printing technology is explored in a few decades back, which can alter their dimensions temporarily under shear stress, showing potential healing/recovery tendency with patient-specific intervention toward the development of personalized medicine. Thus, self-healing injectable hydrogels (IHs) are stunning toward developing a paradigm for tissue regeneration. This review comprises the designing of IHs, rheological characterization and stability, several benchmark consequences for self-healing IHs, their translation into tissue regeneration of specific types, applications of IHs in biomedical such as anticancer and immunomodulation, wound healing and tissue/bone regeneration, antimicrobial potentials, drugs, gene and vaccine delivery, ocular delivery, 3D printing, cosmeceuticals, and photothermal therapy as well as in other allied avenues like agriculture, aerospace, electronic/electrical industries, coating approaches, patents associated with therapeutic/nontherapeutic avenues, and numerous futuristic challenges and solutions.

Immunotherapies for locally aggressive cancers

Improving surgical resection outcomes for locally aggressive tumors is key to inducing durable locoregional disease control and preventing progression to metastatic disease. Macroscopically complete resection of the tumor is the standard of care for many cancers, including breast, ovarian, lung, sarcoma, and mesothelioma. Advancements in cancer diagnostics are increasing the number of surgically eligible cases through early detection. Thus, a unique opportunity arises to improve patient outcomes with decreased recurrence rates via intraoperative delivery treatments using local drug delivery strategies after the tumor has been resected. Of the current systemic treatments (e.g., chemotherapy, targeted therapies, and immunotherapies), immunotherapies are the latest approach to offer significant benefits. Intraoperative strategies benefit from direct access to the tumor microenvironment which improves drug uptake to the tumor and simultaneously minimizes the risk of drug entering healthy tissues thereby resulting in fewer or less toxic adverse events. We review the current state of immunotherapy development and discuss the opportunities that intraoperative treatment provides. We conclude by summarizing progress in current research, identifying areas for exploration, and discussing future prospects in sustained remission.

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

Fluorescein-Based SynNotch Adaptors for Regulating Gene Expression Responses to Diverse Extracellular Cues

We introduce an adaptor-based strategy for regulating fluorescein-binding synthetic Notch (SynNotch) receptors using ligands based on conjugates of fluorescein isomers and analogs. To develop a versatile system, we evaluated the surface expression and activities of multiple constructs containing distinct extracellular fluorescein-binding domains. Using an optimized receptor, we devised ways to regulate signaling via fluorescein-based chemical transformations, including an approach based on a bio-orthogonal chemical ligation and a spatially controllable strategy via the photo-patterned uncaging of an o -nitrobenzyl-caged fluorescein conjugate. We further demonstrate that fluorescein-conjugated extracellular matrix (ECM)-binding peptides can regulate SynNotch activity depending on the folding state of collagen-based ECM networks. Treatment with these conjugates enabled cells to distinguish between folded versus denatured collagen proteins and enact dose-dependent gene expression responses depending on the nature of the signaling adaptors presented. To demonstrate the utility of these tools, we applied them to control the myogenic conversion of fibroblasts into myocytes with spatial and temporal precision and in response to denatured collagen-I, a biomarker of multiple pathological states. Overall, we introduce an optimized fluorescein-binding SynNotch as a versatile tool for regulating transcriptional responses to extracellular ligands based on the widely used and clinically-approved fluorescein dye.

Biomaterial-based scaffolds for direct in situ programming of tumor-infiltrating T lymphocytes

Adoptive cell therapy with tumor-infiltrating T cells (TILs) has generated exciting clinical trial results for the treatment of unresectable solid tumors. However, solid tumors remain difficult targets for adoptively transferred T cells, due in part to poor migration of TILs to the tumor, physical barriers to infiltration, and active suppression of TILs by the tumor. Furthermore, a highly skilled team is required to obtain tumor tissue, isolate and expand the TILs ex vivo, and reinfuse them into the patient, which drives up costs and limits patient access. Here, we describe a cell-free polymer implant designed to recruit, genetically reprogram and expand host T cells at tumor lesions in situ. Importantly, the scaffold can be fabricated on a large scale and is stable to lyophilization. Using a mouse breast cancer model, we show that the implants quickly and efficiently amass cancer-specific host lymphocytes at the tumor site in quantities sufficient to bring about long-term tumor regression. Given that surgical care is the mainstay of cancer treatment for many patients, this technology could be easily implemented in a clinical setting as an add-on to surgery for solid tumors. Furthermore, the approach could be broadened to recruit and genetically reprogram other therapeutically desirable host cells, such as macrophages, natural killer cells or dendritic cells, potentially boosting the antitumor effectiveness of the implant even more.