Customized Multifunctional Peptide Hydrogel Scaffolds for CAR-T-Cell Rapid Proliferation and Solid Tumor Immunotherapy

Advances in ligand-based surface engineering strategies for fine-tuning T cell mechanotransduction toward efficient immunotherapy

T cell-based immunotherapy has recently emerged as a promising strategy to treat cancer, requiring the activation of antigen-directed cytotoxicity to eliminate cancer cells. Mechanical signaling, although often overshadowed by its biochemical counterpart, plays a crucial role in T cell anticancer responses, from activation to cytolytic killing. Rapid advancements in the fields of chemistry, biomaterials, and micro/nanoengineering offer an interdisciplinary approach to incorporating mechano- and immunomodulatory ligands, including but not limited to synthetic peptides, small molecules, cytokines, and artificial antigens, onto the biomaterial-based platforms to modulate mechanotransducive processes in T cells. The surface engineering of these immunomodulatory ligands with optimization of ligand density, geometrical arrangement, and mobility has been proven to better mimic the natural ligation between immunoreceptors and ligands to directly enhance or inhibit mechanotransduction pathways in T cells, through triggering upstream mechanosensitive channels, adhesion molecules, cytoskeletal components, or downstream mechanoimmunological regulators. Despite its tremendous potential, current research on this new biomaterial surface engineering approach for mechanomodulatory T cell activation and effector functions remains in a nascent stage. This review highlights the recent progress in this new direction, focusing on achievements in mechanomodulatory ligand-based surface engineering strategies and underlying principles, and outlooks the further research in the rapidly evolving field of T cell mechanotransduction engineering for efficient immunotherapy.

Peptide-based supramolecular hydrogels and their biotherapeutic applications

In recent years, supramolecular hydrogels have made groundbreaking research progress in biomedical fields such as drug delivery, biosensing, imaging analysis, and tissue engineering. Peptides, with their unique characteristics of facile preparation, low immunogenicity and easy biodegradability, are commonly used as building blocks of supramolecular hydrogels. Peptide-based supramolecular hydrogels loaded with drugs, prepared via physical means or covalent crosslinking, exhibit unique three-dimensional network structures and strong water retention capacities. These properties enhance drug bioavailability and reduce side effects, enabling drug accumulation and responsive release at disease sites, significantly improving the therapeutic efficacy. Here, we review recent advancements in peptide-based supramolecular hydrogels and their biotherapeutic applications, including chemotherapy, photothermal therapy, photodynamic therapy, immunotherapy, gene therapy, antibacterial and anti-inflammatory treatments, and other biological applications. This review aims to provide new inspiration for the development of biomaterials in the therapeutic field and provide more personalized options for disease treatment. Additionally, challenges and limitations in this field are briefly discussed.

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.

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.

Applications of self-assembled peptide hydrogels in anti-tumor therapy

Peptides are a class of active substances composed of a variety of amino acids with special physiological functions. The rational design of peptide sequences at the molecular level enables their folding into diverse secondary structures. This property has garnered significant attention in the biomedical sphere owing to their favorable biocompatibility, adaptable mechanical traits, and exceptional loading capabilities. Concurrently with advancements in modern medicine, the diagnosis and treatment of tumors have increasingly embraced targeted and personalized approaches. This review explores recent applications of self-assembled peptides derived from natural amino acids in chemical therapy, immunotherapy, and other adjunctive treatments. We highlighted the utilization of peptide hydrogels as delivery systems for chemotherapeutic drugs and other bioactive molecules and then discussed the challenges and prospects for their future application.

Engineered Bio-Based Hydrogels for Cancer Immunotherapy

Immunotherapy represents a revolutionary paradigm in cancer management, showcasing its potential to impede tumor metastasis and recurrence. Nonetheless, challenges including limited therapeutic efficacy and severe immune-related side effects are frequently encountered, especially in solid tumors. Hydrogels, a class of versatile materials featuring well-hydrated structures widely used in biomedicine, offer a promising platform for encapsulating and releasing small molecule drugs, biomacromolecules, and cells in a controlled manner. Immunomodulatory hydrogels present a unique capability for augmenting immune activation and mitigating systemic toxicity through encapsulation of multiple components and localized administration. Notably, hydrogels based on biopolymers have gained significant interest owing to their biocompatibility, environmental friendliness, and ease of production. This review delves into the recent advances in bio-based hydrogels in cancer immunotherapy and synergistic combinatorial approaches, highlighting their diverse applications. It is anticipated that this review will guide the rational design of hydrogels in the field of cancer immunotherapy, fostering clinical translation and ultimately benefiting patients.

Mechanical forces amplify TCR mechanotransduction in T cell activation and function

Adoptive T cell immunotherapies, including engineered T cell receptor (eTCR) and chimeric antigen receptor (CAR) T cell immunotherapies, have shown efficacy in treating a subset of hematologic malignancies, exhibit promise in solid tumors, and have many other potential applications, such as in fibrosis, autoimmunity, and regenerative medicine. While immunoengineering has focused on designing biomaterials to present biochemical cues to manipulate T cells ex vivo and in vivo, mechanical cues that regulate their biology have been largely underappreciated. This review highlights the contributions of mechanical force to several receptor-ligand interactions critical to T cell function, with central focus on the TCR-peptide-loaded major histocompatibility complex (pMHC). We then emphasize the role of mechanical forces in (i) allosteric strengthening of the TCR-pMHC interaction in amplifying ligand discrimination during T cell antigen recognition prior to activation and (ii) T cell interactions with the extracellular matrix. We then describe approaches to design eTCRs, CARs, and biomaterials to exploit TCR mechanosensitivity in order to potentiate T cell manufacturing and function in adoptive T cell immunotherapy.

Immune-cell-mediated tissue engineering strategies for peripheral nerve injury and regeneration

During the process of peripheral nerve repair, there are many complex pathological and physiological changes, including multi-cellular responses and various signaling molecules, and all these events establish a dynamic microenvironment for axon repair, regeneration, and target tissue/organ reinnervation. The immune system plays an indispensable role in the process of nerve repair and function recovery. An effective immune response not only involves innate-immune and adaptive-immune cells but also consists of chemokines and cytokines released by these immune cells. The elucidation of the orchestrated interplay of immune cells with nerve regeneration and functional restoration is meaningful for the exploration of therapeutic strategies. This review mainly enumerates the general immune cell response to peripheral nerve injury and focuses on their contributions to functional recovery. The tissue engineering-mediated strategies to regulate macrophages and T cells through physical and biochemical factors combined with scaffolds are discussed. The dynamic immune responses during peripheral nerve repair and immune-cell-mediated tissue engineering methods are presented, which provide a new insight and inspiration for immunomodulatory therapies in peripheral nerve regeneration.

Recent advances in biomaterial designs for assisting CAR-T cell therapy towards potential solid tumor treatment

Chimeric antigen receptor T (CAR-T) cells have shown promising outcomes in the treatment of hematologic malignancies. However, CAR-T cell therapy in solid tumor treatment has been significantly hindered, due to the complex manufacturing process, difficulties in proliferation and infiltration, lack of precision, or poor visualization ability. Fortunately, recent reports have shown that functional biomaterial designs such as nanoparticles, polymers, hydrogels, or implantable scaffolds might have potential to address the above challenges. In this review, we aim to summarize the recent advances in the designs of functional biomaterials for assisting CAR-T cell therapy for potential solid tumor treatments. Firstly, by enabling efficient CAR gene delivery in vivo and in vitro, functional biomaterials can streamline the difficult process of CAR-T cell therapy manufacturing. Secondly, they might also serve as carriers for drugs and bioactive molecules, promoting the proliferation and infiltration of CAR-T cells. Furthermore, a number of functional biomaterial designs with immunomodulatory properties might modulate the tumor microenvironment, which could provide a platform for combination therapies or improve the efficacy of CAR-T cell therapy through synergistic therapeutic effects. Last but not least, the current challenges with biomaterials-based CAR-T therapies will also be discussed, which might be helpful for the future design of CAR-T therapy in solid tumor treatment.

Elevating the potential of CAR-T cell therapy in solid tumors: exploiting biomaterials-based delivery techniques

Chimeric antigen receptor (CAR) T cells exhibit promising progress in addressing hematologic malignancies. However, CAR-T therapy for solid tumors remains limited, with no FDA-approved CAR-T products available for clinical use at present. Primary reasons include insufficient infiltration, accumulation, tumor immunosuppression of the microenvironment, and related side effects. Single utilization of CAR-T cannot effectively overcome these unfavorable obstacles. A probable effective pathway to achieve a better CAR-T therapy effect would be to combine the benefits of biomaterials-based technology. In this article, comprehensive biomaterials strategies to break through these obstacles of CAR-T cell therapy at the tumor sites are summarized, encompassing the following aspects: 1) generating orthotopic CAR-T cells; 2) facilitating CAR-T cell trafficking; 3) stimulating CAR-T cell expansion and infiltration; 4) improving CAR-T cell activity and persistence; 5) reprogramming the immunosuppressive microenvironments. Additionally, future requirements for the development of this field, with a specific emphasis on promoting innovation and facilitating clinical translation, are thoroughly discussed.

Injectable hydrogels for personalized cancer immunotherapies

The field of cancer immunotherapy has shown significant growth, and researchers are now focusing on effective strategies to enhance and prolong local immunomodulation. Injectable hydrogels (IHs) have emerged as versatile platforms for encapsulating and controlling the release of small molecules and cells, drawing significant attention for their potential to enhance antitumor immune responses while inhibiting metastasis and recurrence. IHs delivering natural killer (NK) cells, T cells, and antigen-presenting cells (APCs) offer a viable method for treating cancer. Indeed, it can bypass the extracellular matrix and gradually release small molecules or cells into the tumor microenvironment, thereby boosting immune responses against cancer cells. This review provides an overview of the recent advancements in cancer immunotherapy using IHs for delivering NK cells, T cells, APCs, chemoimmunotherapy, radio-immunotherapy, and photothermal-immunotherapy. First, we introduce IHs as a delivery matrix, then summarize their applications for the local delivery of small molecules and immune cells to elicit robust anticancer immune responses. Additionally, we discuss recent progress in IHs systems used for local combination therapy, including chemoimmunotherapy, radio-immunotherapy, photothermal-immunotherapy, photodynamic-immunotherapy, and gene-immunotherapy. By comprehensively examining the utilization of IHs in cancer immunotherapy, this review aims to highlight the potential of IHs as effective carriers for immunotherapy delivery, facilitating the development of innovative strategies for cancer treatment. In addition, we demonstrate that using hydrogel-based platforms for the targeted delivery of immune cells, such as NK cells, T cells, and dendritic cells (DCs), has remarkable potential in cancer therapy. These innovative approaches have yielded substantial reductions in tumor growth, showcasing the ability of hydrogels to enhance the efficacy of immune-based treatments. STATEMENT OF SIGNIFICANCE: As cancer immunotherapy continues to expand, the mode of therapeutic agent delivery becomes increasingly critical. This review spotlights the forward-looking progress of IHs, emphasizing their potential to revolutionize localized immunotherapy delivery. By efficiently encapsulating and controlling the release of essential immune components such as T cells, NK cells, APCs, and various therapeutic agents, IHs offer a pioneering pathway to amplify immune reactions, moderate metastasis, and reduce recurrence. Their adaptability further shines when considering their role in emerging combination therapies, including chemoimmunotherapy, radio-immunotherapy, and photothermal-immunotherapy. Understanding IHs' significance in cancer therapy is essential, suggesting a shift in cancer treatment dynamics and heralding a novel period of focused, enduring, and powerful therapeutic strategies.

Bionic peptide scaffold in situ polarization and recruitment of M2 macrophages to promote peripheral nerve regeneration

Tissue regeneration requires exogenous and endogenous signals, and there is increasing evidence that the exogenous microenvironment may play an even more dominant role in the complex process of coordinated multiple cells. The short-distance peripheral nerve showed a spontaneous regenerative phenomenon, which was initiated by the guiding role of macrophages. However, it cannot sufficiently restore long-distance nerve injury by itself. Based on this principle, we firstly constructed a proinflammatory model to prove that abnormal M2 expression reduce the guidance and repair effect of long-distance nerves. Furthermore, a bionic peptide hydrogel scaffold based on self-assembly was developed to envelop M2-derived regenerative cytokines and extracellular vesicles (EVs). The cytokines and EVs were quantified to mimic the guidance and regenerative microenvironment in a direct and mild manner. The bionic scaffold promoted M2 transformation in situ and led to proliferation and migration of Schwann cells, neuron growth and motor function recovery. Meanwhile, the peptide scaffold combined with CX3CL1 recruited more blood-derived M2 macrophages to promote long-distance nerve reconstruction. Overall, we systematically confirmed the important role of M2 in regulating and restoring the injury peripheral nerve. This bionic peptide hydrogel scaffold mimicked and remodeled the local environment for M2 transformation and recruitment, favoring long-distance peripheral nerve regeneration. It can help to explicate regulative effect of M2 may be a cause not just a consequence in nerve repair and tissue integration, which facilitating the development of pro-regenerative biomaterials.

Advanced Materials and Delivery Systems for Enhancement of Chimeric Antigen Receptor Cells

Chimeric antigen receptor (CAR) cell therapy is a great success and breakthrough in immunotherapy. However, there are still lots of barriers to its wide use in clinical, including long time consumption, high cost, and failure against solid tumors. For these challenges, researches are deplored to explore CAR cells to more appliable products in clinical. This minireview focuses on the advanced non-viral materials for CAR-T transfection ex vivo with better performance, delivery systems combined with other therapy for enhancement of CAR-T therapy in solid tumors. In addition, the targeted delivery platform for CAR cells in vivo generation as a breakthrough technology as its low cost and convenience. In the end, the prospective direction and future of CAR cell therapy are discussed.

Mechano-modulation of T cells for cancer immunotherapy

Immunotherapy, despite its promise for future anti-cancer approach, faces significant challenges, such as off-tumor side effects, innate or acquired resistance, and limited infiltration of immune cells into stiffened extracellular matrix (ECM). Recent studies have highlighted the importance of mechano-modulation/-activation of immune cells (mainly T cells) for effective caner immunotherapy. Immune cells are highly sensitive to the applied physical forces and matrix mechanics, and reciprocally shape the tumor microenvironment. Engineering T cells with tuned properties of materials (e.g., chemistry, topography, and stiffness) can improve their expansion and activation ex vivo, and their ability to mechano-sensing the tumor specific ECM in vivo where they perform cytotoxic effects. T cells can also be exploited to secrete enzymes that soften ECM, thus increasing tumor infiltration and cellular therapies. Furthermore, T cells, such as chimeric antigen receptor (CAR)-T cells, genomic engineered to be spatiotemporally controllable by physical stimuli (e.g., ultrasound, heat, or light), can mitigate adverse off-tumor effects. In this review, we communicate these recent cutting-edge endeavors devoted to mechano-modulating/-activating T cells for effective cancer immunotherapy, and discuss future prospects and challenges in this field.