Thermoreversible poly(ethylene glycol)-g-chitosan hydrogel as a therapeutic T lymphocyte depot for localized glioblastoma immunotherapy

Thermosensitive injectable fibrillar gels based on cellulose nanocrystals grafted with poly(N-isopropylacrylamide) as biocompatible brain implants

Drug treatment of glioblastoma, the most aggressive and widespread form of brain cancer, is complicated due to the difficulty of penetration of chemotherapeutic drugs through the blood-brain barrier (BBB). Moreover, with surgical removal of tumors, in 90 % of cases they reappear near the original focus. To solve this problem, we propose to use hydrogel based on cellulose nanocrystals grafted with poly(N-isopropylacrylamide) (CNC-g-PNIPAM) as a promising material for filling postoperative cavities in the brain with the release of antitumor drugs. The CNC-g-PNIPAM is formed by "grafting to" method for precise control of molecular weight and grafting density. This colloidal system is liquid under injection conditions (at r. t.) and turns into a gel at human body temperature (when filling the postoperative area). It was shown for the first time that due to the rod-shaped of CNC, the gel has a fibrillar structure and, thus, mechanical properties similar to those of brain tissue, including nonlinear mechanics (strain-stiffening and compression softening). The biocompatibility of the hydrogel with primary brain cells is demonstrated. In addition, the release of the antitumor drug paclitaxel from the hydrogel and its antitumor activity is shown. The resulting nanocolloid system provides an innovative alternative approach to filling postoperative cavities and can be used for postoperative treatment due to the programmable release of drugs, as well as for in vitro modeling of tumor interaction with the BBB affecting drug transport in the brain.

Doxorubicin-loaded liposome-like particles embedded in chitosan/hyaluronic acid-based hydrogels as a controlled drug release model for local treatment of glioblastoma

Glioblastoma (GBM) resection and medication treatment are limited, and local drug therapies are required. This study aims to create a hybrid system comprising liposome-like particles (LLP-DOX) encapsulated in chitosan/hyaluronic acid/polyethyleneimine (CHI/HA/PEI) hydrogels, enabling controlled local delivery of doxorubicin (DOX) into the resection cavity for treating GBM. CHI/HA/PEI hydrogels were characterized morphologically, physically, chemically, mechanically, and thermally. Findings revealed a high network and compact micro-network structure, along with enhanced physical and thermal stability compared to CHI/HA hydrogels. Simultaneously, drug release from CHI/HA/PEI/LLP-DOX hydrogels was assessed, revealing continuous and controlled release up to the 148th hour, with no significant burst release. Cell studies showed that CHI/HA/PEI hydrogels are biocompatible with low genotoxicity. Additionally, LLP-DOX-loaded CHI/HA/PEI hydrogels significantly decreased cell viability and gene expression levels compared to LLP-DOX alone. It was also observed that the viability of GBM spheroids decreased over time when interacting with CHI/HA/PEI/LLP-DOX hydrogels, accompanied by a reduction in total surface area and an increase in apoptotic tendencies. In this study, we hypothesized that creating a hybrid drug delivery system by encapsulating DOX-loaded LLPs within a CHI/HA/PEI hydrogel matrix could achieve sustained drug release, improve anticancer efficacy via localized treatment, and effectively mitigate GBM progression for 3D microtissues.

Nanogel: A versatile drug delivery system for the treatment of various diseases and their future perspective

Nanogel (NG) drug delivery systems have emerged as promising tools for targeted and controlled drug release, revolutionizing treatment approaches across various diseases. Their unique physicochemical properties, such as nano size, high surface area, biocompatibility, stability, and tunable drug release, make them ideal carriers for a wide range of therapeutic agents. Nanogels (NGs), characterized by their 3D network of crosslinked polymers, offer unique edges like high drug loading capacity, controlled release, and targeted delivery. Additionally, the diverse applications of NGs in medical therapeutics highlight their versatility and potential impact on improving patient outcomes. Their application spans cancer treatment, infectious diseases, and chronic conditions, allowing for precise drug delivery to specific tissues or cells, minimizing side effects, and enhancing therapeutic efficacy. Despite their potential, challenges such as scalability, manufacturing reproducibility, and regulatory hurdles must be addressed. Achieving clinical translation requires overcoming these obstacles to ensure therapeutic payloads' safe and efficient delivery. Strategies such as surface modification and incorporating stimuli-responsive elements enhanced NG performance and addressed specific therapeutic challenges. Advances in nanotechnology, biomaterials, and targeted drug design offer opportunities to improve the performance of NGs and address current limitations. Tailoring NGs for exploring combination therapies and integrating diagnostics for real-time monitoring represent promising avenues for future research. In conclusion, NG drug delivery systems have demonstrated tremendous potential in diverse disease applications. Overcoming challenges and leveraging emerging technologies will pave the way for their widespread clinical implementation, ushering in a new era of precision medicine and improved patient care.

Injectable Biodegradable Chitosan-PEG/PEG-Dialdehyde Hydrogel for Stem Cell Delivery and Cartilage Regeneration

Stem cell-based therapy holds promise for cartilage regeneration in treating knee osteoarthritis (KOA). Injectable hydrogels have been developed to mimic the extracellular matrix (ECM) and facilitate stem cell growth, proliferation, and differentiation. However, these hydrogels face limitations such as poor mechanical strength, inadequate biocompatibility, and suboptimal biodegradability, collectively hindering their effectiveness in cartilage regeneration. This study introduces an injectable, biodegradable, and self-healing hydrogel composed of chitosan-PEG and PEG-dialdehyde for stem cell delivery. This hydrogel can form in situ by blending two polymer solutions through injection at physiological temperature, encapsulating human adipose-derived stem cells (hADSCs) during the gelation process. Featuring a 3D porous structure with large pore size, optimal mechanical properties, biodegradability, easy injectability, and rapid self-healing capability, the hydrogel supports the growth, proliferation, and differentiation of hADSCs. Notably, encapsulated hADSCs form 3D spheroids during proliferation, with their sizes increasing over time alongside hydrogel degradation while maintaining high viability for at least 10 days. Additionally, hADSCs encapsulated in this hydrogel exhibit upregulated expression of chondrogenic differentiation genes and proteins compared to those cultured on 2D surfaces. These characteristics make the chitosan-PEG/PEG-dialdehyde hydrogel-stem cell construct suitable for direct implantation through minimally invasive injection, enhancing stem cell-based therapy for KOA and other cell-based treatments.

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.

Multifunctional Nanocarriers for Alzheimer's Disease: Befriending the Barriers

Neurodegenerative diseases (NDDs) have been increasing in incidence in recent years and are now widespread worldwide. Neuronal death is defined as the progressive loss of neuronal structure or function which is closely associated with NDDs and represents the intrinsic features of such disorders. Amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's, Parkinson's, and Huntington's diseases (AD, PD, and HD, respectively) are considered neurodegenerative diseases that affect a large number of people worldwide. Despite the testing of various drugs, there is currently no available therapy that can remedy or effectively slow the progression of these diseases. Nanomedicine has the potential to revolutionize drug delivery for the management of NDDs. The use of nanoparticles (NPs) has recently been developed to improve drug delivery efficiency and is currently subjected to extensive studies. Nanoengineered particles, known as nanodrugs, can cross the blood-brain barrier while also being less invasive compared to the most treatment strategies in use. Polymeric, magnetic, carbonic, and inorganic NPs are examples of NPs that have been developed to improve drug delivery efficiency. Primary research studies using NPs to cure AD are promising, but thorough research is needed to introduce these approaches to clinical use. In the present review, we discussed the role of metal-based NPs, polymeric nanogels, nanocarrier systems such as liposomes, solid lipid NPs, polymeric NPs, exosomes, quantum dots, dendrimers, polymersomes, carbon nanotubes, and nanofibers and surfactant-based systems for the therapy of neurodegenerative diseases. In addition, we highlighted nanoformulations such as N-butyl cyanoacrylate, poly(butyl cyanoacrylate), D-penicillamine, citrate-coated peptide, magnetic iron oxide, chitosan (CS), lipoprotein, ceria, silica, metallic nanoparticles, cholinesterase inhibitors, an acetylcholinesterase inhibitors, metal chelators, anti-amyloid, protein, and peptide-loaded NPs for the treatment of AD.

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.

Nanofibrous MultiDomain Peptide Hydrogels Provide T Cells a 3D, Cytocompatible Environment for Cell Expansion and Antigen-Specific Killing

T cells have the ability to recognize and kill specific target cells, giving therapies based on their potential for treating infection, diabetes, cancer, and other diseases. However, the advancement of T cell-based treatments has been hindered by difficulties in their ex vivo activation and expansion, the number of cells required for sustained in vivo levels, and preferential localization following systemic delivery. Biomaterials may help to overcome many of these challenges by providing a combined means of proliferation, antigen presentation, and cell localization upon delivery. In this work, we studied self-assembling Multidomain Peptides (MDPs) as scaffolds for T cell culture, activation, and expansion. We evaluated the effect of different MDP chemistries on their biocompatibility with T cells and the maintenance of antigen specificity for T cells cultured in the hydrogels. We also examined the potential application of MDPs as scaffolds for T cell activation and expansion and the effect of MDP encapsulation on T cell phenotype. We found high cell viability when T cells were encapsulated in noncationic MDPs, O5 and D2, and superior retention of antigen specificity and tumor-reactivity were preserved in the anionic MDP, D2. Maintenance of antigen recognition by T cells in D2 hydrogels was confirmed by quantifying immune synapses of T Cells engaged with antigen-presenting cancer cells. When 3D cultured in anionic MDP D2 coloaded with anti-CD3, anti-CD28, IL2, IL7, and IL15, we observed successful T cell proliferation evidenced by upregulation of CD27 and CD107a. This study is the first to investigate the potential of self-assembling peptide-based hydrogels as 3D scaffolds for human T cell applications and demonstrates that MDP hydrogels are a viable platform for enabling T cell in vitro activation, expansion, and maintenance of antigen specificity and therefore a promising tool for future T cell-based therapies.

Blood-brain barrier disruption in dementia: Nano-solutions as new treatment options

Candidate drugs targeting the central nervous system (CNS) demonstrate extremely low clinical success rates, with more than 98% of potential treatments being discontinued due to poor blood-brain barrier (BBB) permeability. Neurological conditions were shown to be the second leading cause of death globally in 2016, with the number of people currently affected by neurological disorders increasing rapidly. This increasing trend, along with an inability to develop BBB permeating drugs, is presenting a major hurdle in the treatment of CNS-related disorders, like dementia. To overcome this, it is necessary to understand the structure and function of the BBB, including the transport of molecules across its interface in both healthy and pathological conditions. The use of CNS drug carriers is rapidly gaining popularity in CNS research due to their ability to target BBB transport systems. Further research and development of drug delivery vehicles could provide essential information that can be used to develop novel treatments for neurological conditions. This review discusses the BBB and its transport systems and evaluates the potential of using nanoparticle-based delivery systems as drug carriers for CNS disease with a focus on dementia.

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.

Glioma stem cells remodel immunotolerant microenvironment in GBM and are associated with therapeutic advancements

Glioma is the most common primary tumor of the central nervous system (CNS). Glioblastoma (GBM) is incurable with current treatment strategies. Additionally, the treatment of recurrent GBM (rGBM) is often referred to as terminal treatment, necessitating hospice-level care and management. The presence of the blood-brain barrier (BBB) gives GBM a more challenging or "cold" tumor microenvironment (TME) than that of other cancers and gloma stem cells (GSCs) play an important role in the TME remodeling, occurrence, development and recurrence of giloma. In this review, our primary focus will be on discussing the following topics: niche-associated GSCs and macrophages, new theories regarding GSC and TME involving pyroptosis and ferroptosis in GBM, metabolic adaptations of GSCs, the influence of the cold environment in GBM on immunotherapy, potential strategies to transform the cold GBM TME into a hot one, and the advancement of GBM immunotherapy and GBM models.

Drug delivery methods for cancer immunotherapy

Despite the fact that numerous immunotherapy-based drugs have been approved by the FDA for the treatment of primary and metastatic tumors, only a small proportion of the population can benefit from them because of primary and acquired resistances. Moreover, the translation of immunotherapy from the bench to the clinical practice is being challenging because of the short half-lives of the involved molecules, the difficulties to accomplish their delivery to the target sites, and some serious adverse effects that are being associated with these approaches. The emergence of drug delivery vehicles in the field of immunotherapy is helping to overcome these difficulties and limitations and this review describes how, providing some illustrative examples. Moreover, this article provides an exhaustive review of the studies that have been published to date on the particular case of hematological cancers. (Created with BioRender).

Designing Hydrogels for Immunomodulation in Cancer Therapy and Regenerative Medicine

The immune system not only acts as a defense against pathogen and cancer cells, but also plays an important role in homeostasis and tissue regeneration. Targeting immune systems is a promising strategy for efficient cancer treatment and regenerative medicine. Current systemic immunomodulation therapies are usually associated with low persistence time, poor targeting to action sites, and severe side effects. Due to their extracellular matrix-mimetic nature, tunable properties and diverse bioactivities, hydrogels are intriguing platforms to locally deliver immunomodulatory agents and cells, as well as provide an immunomodulatory microenvironment to recruit, activate, and expand host immune cells. In this review, the design considerations, including polymer backbones, crosslinking mechanisms, physicochemical nature, and immunomodulation-related components, of the hydrogel platforms, are focused on. The immunomodulatory effects and therapeutic outcomes in cancer therapy and tissue regeneration of different hydrogel systems are emphasized, including hydrogel depots for delivery of immunomodulatory agents, hydrogel scaffolds for cell delivery, and immunomodulatory hydrogels depending on the intrinsic properties of materials. Finally, the remained challenges in current systems and future development of immunomodulatory hydrogels are discussed.

Cancer Immunotherapy Using Bioengineered Micro/Nano Structured Hydrogels

Hydrogels, a class of materials with a 3D network structure, are widely used in various applications of therapeutic delivery, particularly cancer therapy. Micro and nanogels as miniaturized structures of the bioengineered hydrogels may provide extensive benefits over the common hydrogels in encapsulation and controlled release of small molecular drugs, macromolecular therapeutics, and even cells. Cancer immunotherapy is rapidly developing, and micro/nanostructured hydrogels have gained wide attention regarding their engineered payload release properties that enhance systemic anticancer immunity. Additionally, they are a great candidate due to their local administration properties with a focus on local immune cell manipulation in favor of active and passive immunotherapies. Although applied locally, such micro/nanostructured can also activate systemic antitumor immune responses by releasing nanovaccines safely and effectively inhibiting tumor metastasis and recurrence. However, such hydrogels are mostly used as locally administered carriers to stimulate the immune cells by releasing tumor lysate, drugs, or nanovaccines. In this review, the latest developments in cancer immunotherapy are summarized using micro/nanostructured hydrogels with a particular emphasis on their function depending on the administration route. Moreover, the potential for clinical translation of these hydrogel-based cancer immunotherapies is also discussed.

Local immunotherapy of glioblastoma: A comprehensive review of the concept

Despite advancements in standard treatments, the prognosis of Glioblastoma (GBM) remains poor, prompting research for novel therapies. Immunotherapy is a promising treatment option for GBM, and many immunotherapeutic agents are currently under investigation. Chimeric antigen receptor (CAR) T cells are rapidly evolving in immunotherapy of GBM with many clinical trials showing efficacy of CAR T cells exerting anti-tumor activity following recognition of tumor-associated antigens (TAAs). Exhaustion in CAR T cells can reduce their capacity for long-term persistence and anti-tumor action. Local immunotherapy, which targets the tumor microenvironment and creates a more hospitable immunological environment for CAR T cells, has the potential to reduce CAR T cell exhaustion and increase immunity. Tertiary lymphoid structures (TLS) are ectopic lymphoid-like formations that can develop within the tumor microenvironment or in other non-lymphoid tissues. As a comprehensive local immunotherapy tool, the incorporation of TLS into an implanted biodegradable scaffold has amazing immunotherapeutic potential. The immune response to GBM can be improved even further by strategically inserting a stimulator of interferon genes (STING) agonist into the scaffold. Additionally, the scaffold's addition of glioma stem cells (GSC), which immunotherapeutic approaches may use to target, enhances the removal of cancer cells from their source. Furthermore, it has been demonstrated that GSCs have an impact on TLS formation, which helps to create a favorable tumor microenvironment. Herein, we overview local delivery of a highly specific tandem AND-gate CAR T cell along with above mentioned components. A multifaceted approach that successfully engages the immune system to mount an efficient targeted immune response against GBM is provided by the integration of CAR T cells, TLS, STING agonists, and GSCs within an implantable biodegradable scaffold. This approach offers a promising therapeutic approach for patients with GBM.

Nanogels as novel drug nanocarriers for CNS drug delivery

Nanogels are highly recognized as adaptable drug delivery systems that significantly contribute to improving various therapies and diagnostic examinations for different human diseases. These three-dimensional, hydrophilic cross-linked polymers have the ability to absorb large amounts of water or biological fluids. Due to the growing demand for enhancing current therapies, nanogels have emerged as the next-generation drug delivery system. They effectively address the limitations of conventional drug therapy, such as poor stability, large particle size, and low drug loading efficiency. Nanogels find extensive use in the controlled delivery of therapeutic agents, reducing adverse drug effects and enabling lower therapeutic doses while maintaining enhanced efficacy and patient compliance. They are considered an innovative drug delivery system that highlights the shortcomings of traditional methods. This article covers several topics, including the involvement of nanogels in the nanomedicine sector, their advantages and limitations, ideal properties like biocompatibility, biodegradability, drug loading capacity, particle size, permeability, non-immunological response, and colloidal stability. Additionally, it provides information on nanogel classification, synthesis, drug release mechanisms, and various biological applications. The article also discusses barriers associated with brain targeting and the progress of nanogels as nanocarriers for delivering therapeutic agents to the central nervous system.

Polysaccharide-based nanoassemblies: From synthesis methodologies and industrial applications to future prospects

Polysaccharides, due to their remarkable features, have gained significant prominence in the sustainable production of nanoparticles (NPs). High market demand and minimal production cost, compared to the chemically synthesised NPs, demonstrate a drive towards polysaccharide-based nanoparticles (PSNPs) benign to environment. Various approaches are used for the synthesis of PSNPs including cross-linking, polyelectrolyte complexation, and self-assembly. PSNPs have the potential to replace a wide diversity of chemical-based agents within the food, health, medical and pharmacy sectors. Nevertheless, the considerable challenges associated with optimising the characteristics of PSNPs to meet specific targeting applications are of utmost importance. This review provides a detailed compilation of recent accomplishments in the synthesis of PSNPs, the fundamental principles and critical factors that govern their rational fabrication, as well as various characterisation techniques. Noteworthy, the multiple use of PSNPs in different disciplines such as biomedical, cosmetics agrochemicals, energy storage, water detoxification, and food-related realms, is accounted in detail. Insights into the toxicological impacts of the PSNPs and their possible risks to human health are addressed, and efforts made in terms of PSNPs development and optimising strategies that allow for enhanced delivery are highlighted. Finally, limitations, potential drawbacks, market diffusion, economic viability and future possibilities for PSNPs to achieve widespread commercial use are also discussed.

Long-Acting Therapeutic Delivery Systems for the Treatment of Gliomas

Despite the emergence of cutting-edge therapeutic strategies and tremendous progress in research, a complete cure of glioma remains elusive. The heterogenous nature of tumor, immunosuppressive state and presence of blood brain barrier are few of the major obstacles in this regard. Long-acting depot formulations such as injectables and implantables are gaining attention for drug delivery to brain owing to their ease in administration and ability to elute drug locally for extended durations in a controlled manner with minimal toxicity. Hybrid matrices fabricated by incorporating nanoparticulates within such systems help to enhance pharmaceutical advantages. Utilization of long-acting depots as monotherapy or in conjunction with existing strategies rendered significant survival benefits in many preclinical studies and some clinical trials. The discovery of novel targets, immunotherapeutic strategies and alternative drug administration routes are now coupled with several long-acting systems with an ultimate aim to enhance patient survival and prevent glioma recurrences.

Loco-regional treatment with temozolomide-loaded thermogels prevents glioblastoma recurrences in orthotopic human xenograft models

Glioblastoma multiforme (GBM) is the most aggressive primary tumor of the central nervous system and the diagnosis is often dismal. GBM pharmacological treatment is strongly limited by its intracranial location beyond the blood-brain barrier (BBB). While Temozolomide (TMZ) exhibits the best clinical performance, still less than 20% crosses the BBB, therefore requiring administration of very high doses with resulting unnecessary systemic side effects. Here, we aimed at designing new negative temperature-responsive gel formulations able to locally release TMZ beyond the BBB. The biocompatibility of a chitosan-β-glycerophosphate-based thermogel (THG)-containing mesoporous SiO₂ nanoparticles (THG@SiO₂) or polycaprolactone microparticles (THG@PCL) was ascertained in vitro and in vivo by cell counting and histological examination. Next, we loaded TMZ into such matrices (THG@SiO₂-TMZ and THG@PCL-TMZ) and tested their therapeutic potential both in vitro and in vivo, in a glioblastoma resection and recurrence mouse model based on orthotopic growth of human cancer cells. The two newly designed anticancer formulations, consisting in TMZ-silica (SiO₂@TMZ) dispersed in the thermogel matrix (THG@SiO₂-TMZ) and TMZ, spray-dried on PLC and incorporated into the thermogel (THG@PCL-TMZ), induced cell death in vitro. When applied intracranially to a resected U87-MG-Red-FLuc human GBM model, THG@SiO₂-TMZ and THG@PCL-TMZ caused a significant reduction in the growth of tumor recurrences, when compared to untreated controls. THG@SiO₂-TMZ and THG@PCL-TMZ are therefore new promising gel-based local therapy candidates for the treatment of GBM.

T cell-responsive macroporous hydrogels for in situ T cell expansion and enhanced antitumor efficacy

Adoptive T cell therapy has demonstrated great promise for treating cancer and other diseases. While extensive effort has been made to improve ex vivo expansion of T cells, strategies for maintaining the proliferation and function of T cells post adoptive transfer are still lacking. Here we report an injectable T cell-responsive macroporous hydrogel that enables in situ activation and expansion of T cells. The macroporous gel is composed of a polymeric network with dispersed macropores (∼150 μm) that are large enough to home T cells. In the presence of T cells that can gradually disrupt the gel network surrounding the macropores, activation cues can be gradually released for in situ activation and expansion of T cells. This T cell-responsive macroporous gel enables expansion of effector T cells in vivo, is stable over weeks upon subcutaneous injection, and results in enhanced CD8+ T cell response and antitumor efficacy. We further show that the T cell-responsive macroporous gel could achieve comparable antitumor efficacy to conventional T cell therapy with a much lower cell dose. This injectable, T cell-responsive macroporous gel provides a platform for in vivo expansion of engineered T cells in a controlled manner, for timely and effective treatment of diseases.

Cell delivery devices for cancer immunotherapy

Adoptive cell therapy (ACT) that leverages allogeneic or autologous immune cells holds vast promise in targeted cancer therapy. Despite the tremendous success of ACT in treating hematopoietic malignancies, its efficacy is limited in eradicating solid tumors via intravenous infusion of immune cells. With the extending technology of cancer immunotherapy, novel delivery strategies have been explored to improve the therapeutic potency of adoptively transferred cells for solid tumor treatment by innovating the administration route, maintaining the cell viability, and normalizing the tumor microenvironment. In this review, a variety of devices for cell delivery are summarized. Perspectives and challenges of cell delivery devices for cancer immunotherapy are also discussed.

Recent Advances in the Biomedical Applications of Functionalized Nanogels

Nanomaterials have been extensively used in several applications in the past few decades related to biomedicine and healthcare. Among them, nanogels (NGs) have emerged as an important nanoplatform with the properties of both hydrogels and nanoparticles for the controlled/sustained delivery of chemo drugs, nucleic acids, or other bioactive molecules for therapeutic or diagnostic purposes. In the recent past, significant research efforts have been invested in synthesizing NGs through various synthetic methodologies such as free radical polymerization, reversible addition-fragmentation chain-transfer method (RAFT) and atom transfer radical polymerization (ATRP), as well as emulsion techniques. With further polymeric functionalizations using activated esters, thiol-ene/yne processes, imines/oximes formation, cycloadditions, nucleophilic addition reactions of isocyanates, ring-opening, and multicomponent reactions were used to obtain functionalized NGs for targeted delivery of drug and other compounds. NGs are particularly intriguing for use in the areas of diagnosis, analytics, and biomedicine due to their nanodimensionality, material characteristics, physiological stability, tunable multi-functionality, and biocompatibility. Numerous NGs with a wide range of functionalities and various external/internal stimuli-responsive modalities have been possible with novel synthetic reliable methodologies. Such continuous development of innovative, intelligent materials with novel characteristics is crucial for nanomedicine for next-generation biomedical applications. This paper reviews the synthesis and various functionalization strategies of NGs with a focus on the recent advances in different biomedical applications of these surface modified/functionalized single-/dual-/multi-responsive NGs, with various active targeting moieties, in the fields of cancer theranostics, immunotherapy, antimicrobial/antiviral, antigen presentation for the vaccine, sensing, wound healing, thrombolysis, tissue engineering, and regenerative medicine.

Biomaterials for enhanced immunotherapy

Cancer immunotherapies have revolutionized the treatment of numerous cancers, with exciting results often superior to conventional treatments, such as surgery and chemotherapy. Despite this success, limitations such as limited treatment persistence and toxic side effects remain to be addressed to further improve treatment efficacy. Biomaterials offer numerous advantages in the concentration, localization and controlled release of drugs, cancer antigens, and immune cells in order to improve the efficacy of these immunotherapies. This review summarizes and highlights the most recent advances in the use of biomaterials for immunotherapies including drug delivery and cancer vaccines, with a particular focus on biomaterials for immune cell delivery.

Multimodal targeting of glioma with functionalized nanoparticles

The most common and aggressive primitive intracranial tumor of the central nervous system is the glioma. The blood–brain barrier (BBB) has proven to be a significant obstacle to the effective treatment of glioma. To effectively treat glioma, different ways have been used to cross the BBB to deliver drugs to the brain. Drug delivery through nanocarriers proves to be an effective and non-invasive technique for the treatment of glioma and has great potential in the treatment of glioma. In this review, we will provide an overview of nanocarrier-mediated drug delivery and related glioma therapy. Nanocarrier-mediated drug delivery techniques to cross the BBB (liposomes, micelles, inorganic systems, polymeric nanoparticles, nanogel system, and biomimetic nanoparticles) are explored. Finally, the use of nanotherapeutic approaches in the treatment of glioblastoma including chemotherapy, radiotherapy, photothermal therapy, gene therapy, glioma genome editing, immunotherapy, chimeric antigen receptor (CAR) T-cells, immune checkpoint modulators, immune photothermal therapy, vaccine-based immunotherapy, and combination therapy is summarized. Furthermore, this article offers various views on the clinical applicability of nanomedicine.

Immunology Meets Bioengineering: Improving the Effectiveness of Glioblastoma Immunotherapy

Glioblastoma (GBM) therapy has seen little change over the past two decades. Surgical excision followed by radiation and chemotherapy is the current gold standard treatment. Immunotherapy techniques have recently transformed many cancer treatments, and GBM is now at the forefront of immunotherapy research. GBM immunotherapy prospects are reviewed here, with an emphasis on immune checkpoint inhibitors and oncolytic viruses. Various forms of nanomaterials to enhance immunotherapy effectiveness are also discussed. For GBM treatment and immunotherapy, we outline the specific properties of nanomaterials. In addition, we provide a short overview of several 3D (bio)printing techniques and their applications in stimulating the GBM microenvironment. Lastly, the susceptibility of GBM cancer cells to the various immunotherapy methods will be addressed.

Nanomedicine for Glioblastoma: Progress and Future Prospects

Glioblastoma is the most aggressive form of brain tumor, accounting for the highest mortality and morbidity rates. Current treatment for patients with glioblastoma includes maximal safe tumor resection followed by radiation therapy with concomitant temozolomide (TMZ) chemotherapy. The addition of TMZ to the conformal radiation therapy has improved the median survival time only from 12 months to 16 months in patients with glioblastoma. Despite these aggressive treatment strategies, patients' prognosis remains poor. This therapeutic failure is primarily attributed to the blood-brain barrier (BBB) that restricts the transport of TMZ from reaching the tumor site. In recent years, nanomedicine has gained considerable attention among researchers and shown promising developments in clinical applications, including the diagnosis, prognosis, and treatment of glioblastoma tumors. This review sheds light on the morphological and physiological complexity of the BBB. It also explains the development of nanomedicine strategies to enhance the permeability of drug molecules across the BBB.

Injectable Natural Polymer Hydrogels for Treatment of Knee Osteoarthritis

Osteoarthritis (OA) is a serious chronic and degenerative disease that increasingly occurs in the aged population. Its current clinical treatments are limited to symptom relief and cannot regenerate cartilage. Although a better understanding of OA pathophysiology has been facilitating the development of novel therapeutic regimen, delivery of therapeutics to target sites with minimal invasiveness, high retention, and minimal side effects remains a challenge. Biocompatible hydrogels have been recognized to be highly promising for controlled delivery and release of therapeutics and biologics for tissue repair. In this review, the current approaches and the challenges in OA treatment, and unique properties of injectable natural polymer hydrogels as delivery system to overcome the challenges are presented. The common methods for fabrication of injectable polysaccharide-based hydrogels and the effects of their composition and properties on the OA treatment are detailed. The strategies of the use of hydrogels for loading and release cargos are also covered. Finally, recent efforts on the development of injectable polysaccharide-based hydrogels for OA treatment are highlighted, and their current limitations are discussed.

Injectable Diels-Alder cycloaddition hydrogels with tuneable gelation, stiffness and degradation for the sustained release of T-lymphocytes

Engineered T-cell therapies have proven highly efficacious for the treatment of haematological cancers, but translation of this success to solid tumours has been limited, in part, due to difficulties in maintaining high doses at specific target sites. Hydrogel delivery systems that provide a sustained release of T-cells at the target site are emerging as a promising strategy. Therefore, in this study we aimed to develop an injectable hydrogel that gels in situ via efficient Diels-Alder cycloaddition (DAC) chemistry and provides a sustained release of T-cells through gradual hydrolysis of the hydrogel matrix. Hydrogels were prepared via the DAC between fulvene and maleimide functionalised poly(ethylene glycol) (PEG) derivatives. By adjusting the concentration and molecular weight of the functionalised PEGs in the hydrogel formulation the in vitro gelation time (T_gel), initial Young's modulus (E) and degradation time (T_d) could be tailored from 15-150 min, 5-179 kPa and 7-114 h, respectively. Prior to gelation, the formulations could be readily injected through narrow gauge (26 G) needles with the working time correlating closely with the T_gel. A 5 wt% hydrogel formation with conjugated cyclic RGD motif was found to be optimal for the encapsulation and release of CD3⁺ T-cells with a near linear release profile and >70% cell viability over the first 4 d and release continuing out to 7 d. With their tuneable T_gel, T_d and stiffness, the DAC hydrogels provide the opportunity to control the release period and profile of encapsulated cells.

Structure-Based Varieties of Polymeric Nanocarriers and Influences of Their Physicochemical Properties on Drug Delivery Profiles

Carriers are equally important as drugs. They can substantially improve bioavailability of cargos and safeguard healthy cells from toxic effects of certain therapeutics. Recently, polymeric nanocarriers (PNCs) have achieved significant success in delivering drugs not only to cells but also to subcellular organelles. Variety of natural sources, availability of different synthetic routes, versatile molecular architectures, exploitable physicochemical properties, biocompatibility, and biodegradability have presented polymers as one of the most desired materials for nanocarrier design. Recent innovative concepts and advances in PNC-associated nanotechnology are providing unprecedented opportunities to engineer nanocarriers and their functions. The efficiency of therapeutic loading has got considerably increased. Structural design-based varieties of PNCs are widely employed for the delivery of small therapeutic molecules to genes, and proteins. PNCs have gained ever-increasing attention and certainly paves the way to develop advanced nanomedicines. This article presents a comprehensive investigation of structural design-based varieties of PNCs and the influences of their physicochemical properties on drug delivery profiles with perspectives highlighting the inevitability of incorporating both the multi-stimuli-responsive and multi-drug delivery properties in a single carrier to design intelligent PNCs as new and emerging research directions in this rapidly developing area.

Leveraging biomaterials for enhancing T cell immunotherapy

The dynamic roles of T cells in the immune system to recognize and destroy the infected or mutated cells render T cell therapy a prospective treatment for a variety of diseases including cancer, autoimmune diseases, and allograft rejection. However, the clinical applications of T cell therapy remain unsatisfactory due to the tedious manufacturing process, off-target cytotoxicity, poor cell persistence, and associated adverse effects. To this end, various biomaterials have been introduced to enhance T cell therapy by facilitating proliferation, enhancing local enrichment, prolonging retention, and alleviating side effects. This review highlights the design strategies of biomaterials developed for T cell expansion, enrichment, and delivery as well as their corresponding therapeutic effects. The prospects of biomaterials for enhancing T cell immunotherapy are also discussed in this review.

Immunotherapy for glioblastoma: the promise of combination strategies

Glioblastoma (GBM) treatment has remained almost unchanged for more than 20 years. The current standard of care involves surgical resection (if possible) followed by concomitant radiotherapy and chemotherapy. In recent years, immunotherapy strategies have revolutionized the treatment of many cancers, increasing the hope for GBM therapy. However, mostly due to the high, multifactorial immunosuppression occurring in the microenvironment, the poor knowledge of the neuroimmune system and the presence of the blood-brain barrier, the efficacy of immunotherapy in GBM is still low. Recently, new strategies for GBM treatments have employed immunotherapy combinations and have provided encouraging results in both preclinical and clinical studies. The lessons learned from clinical trials highlight the importance of tackling different arms of immunity. In this review, we aim to summarize the preclinical evidence regarding combination immunotherapy in terms of immune and survival benefits for GBM management. The outcomes of recent studies assessing the combination of different classes of immunotherapeutic agents (e.g., immune checkpoint blockade and vaccines) will be discussed. Finally, future strategies to ameliorate the efficacy of immunotherapy and facilitate clinical translation will be provided to address the unmet medical needs of GBM.

Chitosan Nanoparticle-Based System: A New Insight into the Promising Controlled Release System for Lung Cancer Treatment

Lung cancer has been recognized as one of the most often diagnosed and perhaps most lethal cancer diseases worldwide. Conventional chemotherapy for lung cancer-related diseases has bumped into various limitations and challenges, including non-targeted drug delivery, short drug retention period, low therapeutic efficacy, and multidrug resistance (MDR). Chitosan (CS), a natural polymer derived from deacetylation of chitin, and comprised of arbitrarily distributed β-(1-4)-linked d-glucosamine (deacetylated unit) and N-acetyl-d-glucosamine (acetylated unit) that exhibits magnificent characteristics, including being mucoadhesive, biodegradable, and biocompatible, has emerged as an essential element for the development of a nano-particulate delivery vehicle. Additionally, the flexibility of CS structure due to the free protonable amino groups in the CS backbone has made it easy for the modification and functionalization of CS to be developed into a nanoparticle system with high adaptability in lung cancer treatment. In this review, the current state of chitosan nanoparticle (CNP) systems, including the advantages, challenges, and opportunities, will be discussed, followed by drug release mechanisms and mathematical kinetic models. Subsequently, various modification routes of CNP for improved and enhanced therapeutic efficacy, as well as other restrictions of conventional drug administration for lung cancer treatment, are covered.

Precision biomaterials in cancer theranostics and modelling

Despite significant achievements in the understanding and treatment of cancer, it remains a major burden. Traditional therapeutic approaches based on the 'one-size-fits-all' paradigm are becoming obsolete, as demonstrated by the increasing number of patients failing to respond to treatments. In contrast, more precise approaches based on individualized genetic profiling of tumors have already demonstrated their potential. However, even more personalized treatments display shortcomings mainly associated with systemic delivery, such as low local drug efficacy or specificity. A large amount of effort is currently being invested in developing precision medicine-based strategies for improving the efficiency of cancer theranostics and modelling, which are envisioned to be more accurate, standardized, localized, and less expensive. To this end, interdisciplinary research fields, such as biomedicine, material sciences, pharmacology, chemistry, tissue engineering, and nanotechnology, must converge for boosting the precision cancer ecosystem. In this regard, precision biomaterials have emerged as a promising strategy to detect, model, and treat cancer more efficiently. These are defined as those biomaterials precisely engineered with specific theranostic functions and bioactive components, with the possibility to be tailored to the cancer patient needs, thus having a vast potential in the increasing demand for more efficient treatments. In this review, we discuss the latest advances in the field of precision biomaterials in cancer research, which are expected to revolutionize disease management, focusing on their uses for cancer modelling, detection, and therapeutic applications. We finally comment on the needed requirements to accelerate their application in the clinic to improve cancer patient prognosis.

Smart biomaterials to enhance the efficiency of immunotherapy in glioblastoma: State of the art and future perspectives

Glioblastoma multiform (GBM) is considered as the most lethal tumor among CNS malignancies. Although immunotherapy has achieved remarkable advances in cancer treatment, it has not shown satisfactory results in GBM patients. Biomaterial science, along with nanobiotechnology, is able to optimize the efficiency of immunotherapy in these patients. They can be employed to provide the specific activation of immune cells in tumor tissue and combinational therapy as well as preventing systemic adverse effects resulting from hyperactivation of immune responses and off-targeting effect. Advance biomaterials in this field are classified into targeting nanocarriers and localized delivery systems. This review will offer an overview of immunotherapy strategies for glioblastoma and advance delivery systems for immunotherapeutics that may have a high potential in glioblastoma treatment.

Localized delivery of immunotherapeutics: A rising trend in the field

Immunotherapy is becoming a new standard of care for multiple cancers, while several limitations are impending its further clinical success. Immunotherapeutic agents often have inappropriate pharmacokinetics on their own and/or exhibit limited specificity to tumor cells, leading to severe immuno-related adverse effects and limited efficacy. Suitable formulating strategies that confer prolonged contact with or efficient proliferation in tumors while reducing exposure to normal tissues are highly worthy to explore. With the assistance of biomaterial carriers, targeted therapy can be achieved artificially by implanting or injecting drug depots into desired sites, about which the wisdoms in literature have been rich. The relevant results have suggested a "local but systemic" effect, that is, local replenishment of immune modulators achieves a high treatment efficacy that also governs distant metastases, thereby building another rationale for localized delivery. Particularly, implantable scaffolds have been further engineered to recruit disseminated tumor cells with an efficiency high enough to reduce tumor burdens at typical metastatic organs, and simultaneously provide diagnostic signals. This review introduces recent advances in this emerging area along with a perspective on the opportunities and challenges in the way to clinical application.

Rationally designed drug delivery systems for the local treatment of resected glioblastoma

Glioblastoma (GBM) is a particularly aggressive brain cancer associated with high recurrence and poor prognosis. The standard of care, surgical resection followed by concomitant radio- and chemotherapy, leads to low survival rates. The local delivery of active agents within the tumor resection cavity has emerged as an attractive means to initiate oncological treatment immediately post-surgery. This complementary approach bypasses the blood-brain barrier, increases the local concentration at the tumor site while reducing or avoiding systemic side effects. This review will provide a global overview on the local treatment for GBM with an emphasis on the lessons learned from past clinical trials. The main parameters to be considered to rationally design fit-of-purpose biomaterials and develop drug delivery systems for local administration in the GBM resection cavity to prevent the tumor recurrence will be described. The intracavitary local treatment of GBM should i) use materials that facilitate translation to the clinic; ii) be characterized by easy GMP effective scaling up and easy-handling application by the neurosurgeons; iii) be adaptable to fill the tumor-resected niche, mold to the resection cavity or adhere to the exposed brain parenchyma; iv) be biocompatible and possess mechanical properties compatible with the brain; v) deliver a therapeutic dose of rationally-designed or repurposed drug compound(s) into the GBM infiltrative margin. Proof of concept with high translational potential will be provided. Finally, future perspectives to facilitate the clinical translation of the local perisurgical treatment of GBM will be discussed.

Polysaccharide-based nanomedicines for cancer immunotherapy: A review

Cancer immunotherapy is an effective antitumor approach through activating immune systems to eradicate tumors by immunotherapeutics. However, direct administration of "naked" immunotherapeutic agents (such as nucleic acids, cytokines, adjuvants or antigens without delivery vehicles) often results in: (1) an unsatisfactory efficacy due to suboptimal pharmacokinetics; (2) strong toxic and side effects due to low targeting (or off-target) efficiency. To overcome these shortcomings, a series of polysaccharide-based nanoparticles have been developed to carry immunotherapeutics to enhance antitumor immune responses with reduced toxicity and side effects. Polysaccharides are a family of natural polymers that hold unique physicochemical and biological properties, as they could interact with immune system to stimulate an enhanced immune response. Their structures offer versatility in synthesizing multifunctional nanocomposites, which could be chemically modified to achieve high stability and bioavailability for delivering therapeutics into tumor tissues. This review aims to highlight recent advances in polysaccharide-based nanomedicines for cancer immunotherapy and propose new perspectives on the use of polysaccharide-based immunotherapeutics.

Short Review on Advances in Hydrogel-Based Drug Delivery Strategies for Cancer Immunotherapy

Cancer immunotherapy has become the new paradigm of cancer treatment. The introduction and discovery of various therapeutic agents have also accelerated the application of immunotherapy in clinical trials. However, despite the significant potency and demonstrated advantages of cancer immunotherapy, its clinical application to patients faces several safety and efficacy issues, including autoimmune reactions, cytokine release syndrome, and vascular leak syndrome-related issues. In addressing these problems, biomaterials traditionally used for tissue engineering and drug delivery are attracting attention. Among them, hydrogels can be easily injected into tumors with drugs, and they can minimize side effects by retaining immune therapeutics at the tumor site for a long time. This article reviews the status of functional hydrogels for effective cancer immunotherapy. First, we describe the basic mechanisms of cancer immunotherapy and the advantages of using hydrogels to apply these mechanisms. Next, we summarize recent advances in the development of functional hydrogels designed to locally release various immunotherapeutic agents, including cytokines, cancer immune vaccines, immune checkpoint inhibitors, and chimeric antigen receptor-T cells. Finally, we briefly discuss the current problems and possible prospects of hydrogels for effective cancer immunotherapy.

Injectable Hydrogels as Local Depots at Tumor Sites for Antitumor Immunotherapy and Immune-Based Combination Therapy

Despite the encouraging clinical responses of several human cancers to immunotherapy, the efficacy of this treatment remains limited by variable objective response rates and severe systemic immune-related adverse events. To overcome these issues, injectable hydrogels have been developed as local depots that permit the sustained release of single or multiple immunotherapy agents, including traditional immunomodulatory factors, immune checkpoint blocking antibodies, and exogenous immune cells. The antitumor efficacy of immunotherapy can also be enhanced by its combination with other therapeutic approaches, including chemotherapy, radiotherapy, and phototherapy. Despite local treatment strategies, potent systemic antitumor immune responses with low systemic toxicity can be obtained, leading to significant local and abscopal tumor-killing, reduced tumor metastasis, and the prevention of tumor recurrence. This review highlights recent progress in injectable hydrogel-based local depots for tumor immunotherapy and immune-based combination therapy. Moreover, the proposed mechanisms responsible for these antitumor effects are discussed.

Biocompatible copolymer formulations to treat glioblastoma multiforme

The treatment for glioblastoma multiforme (GBM) has not changed for more than 20 years while the prognosis for the patients is still poor and most of them survive less than 1 year after diagnosis. The standard of care for GBM is comprised of surgical resection followed by radiotherapy and oral chemotherapy with temozolomide. The placement of carmustine wafers in the brain after tumour removal is added in cases of recurrent glioma. Significant research is underway to improve the GBM therapy outcome and patient quality of life. Biomaterials are in the front line of the research focus for new treatment options. Specially, biocompatible polymers have been proposed in hydrogel-based formulations aiming at injectable and localized therapies. These formulations can comprise many different pharmacological agents such as chemotherapeutic drugs, nanoparticles, cells, nucleic acids, and diagnostic agents. In this manuscript, we review the most recent formulations developed and tested both in vitro and in vivo using different types of hydrogels. Firstly, we describe three common types of thermo-responsive polymers addressing the advantages and drawbacks of their formulations. Then, we focus on formulations specifically developed for GBM treatment.

Injectable thermoresponsive hydrogels as drug delivery system for the treatment of central nervous system disorders: A review

The central nervous system (CNS), consisting of the brain, spinal cord, and retina, superintends to the acquisition, integration and processing of peripheral information to properly coordinate the activities of the whole body. Neurodegenerative and neurodevelopmental disorders, trauma, stroke, and brain tumors can dramatically affect CNS functions resulting in serious and life-long disabilities. Globally, the societal and economic burden associated with CNS disorders continues to grow with the ageing of the population thus demanding for more effective and definitive treatments. Despite the variety of clinically available therapeutic molecules, medical interventions on CNS disorders are mostly limited to treat symptoms rather than halting or reversing disease progression. This is attributed to the complexity of the underlying disease mechanisms as well as to the unique biological microenvironment. Given its central importance, multiple barriers, including the blood brain barrier and the blood cerebrospinal fluid barrier, protect the CNS from external agents. This limits the access of drug molecules to the CNS thus contributing to the modest therapeutic successes. Loco-regional therapies based on the deposition of thermoresponsive hydrogels loaded with therapeutic agents and cells are receiving much attention as an alternative and potentially more effective approach to manage CNS disorders. In this work, the current understanding and challenges in the design of thermoresponsive hydrogels for CNS therapy are reviewed. First, the biological barriers that hinder mass and drug transport to the CNS are described, highlighting the distinct features of each barrier. Then, the realization, characterization and biomedical application of natural and synthetic thermoresponsive hydrogels are critically presented. Advantages and limitations of each design and application are discussed with the objective of identifying general rules that could enhance the effective translation of thermoresponsive hydrogel-based therapies for the treatment of CNS disorders.

In vivo drug delivery applications of nanogels: a review

In recent years, nanogels have emerged as promising drug delivery vehicles; their ability in holding active molecules, macromolecules and drugs, together with the capability to respond to external stimuli, makes them a suitable tool for a wide range of applications. These features allow nanogels to be exploited against many challenges of nanomedicine associated with different kinds of pathologies which require the use of specific drug delivery systems. In this review our aim is to give the reader an overview of the diseases that can be treated with nanogels as drug delivery systems, such as cancer, CNS disorders, cardiovascular diseases, wound healing and other diseases of human body. For all of these pathologies, biological in vivo assays can be found in the literature and in this work. We focus on the peculiarities of these nanogels, highlighting their features and their advantages in respect to conventional treatments.

GD2-specific CAR T cells encapsulated in an injectable hydrogel control retinoblastoma and preserve vision

Retinoblastoma (RB) is a pediatric retinal tumor that overexpresses the ganglioside GD2. Although it is treatable in patients with early diagnosis, patients may lose one or two eyes. We generated GD2-specific chimeric antigen receptor T lymphocytes (GD2.CAR-Ts) and locally delivered them to mice with an in-situ grafting RB. When used in combination with the local release of interleukin (IL)-15 and an injectable hydrogel, we showed that GD2.CAR-Ts successfully eliminate RB tumor cells without impairment of the mouse vision.

Improving safety of cancer immunotherapy via delivery technology

Breakthroughs in molecular mechanisms underlying immune-suppressive tumor microenvironment and paradigm shifts in the cancer-immunity response cycle have profoundly changed the landscape of cancer immunotherapy. However, one of the challenges is to mitigate the serious side effects caused by systemic autoimmunity and autoinflammatory responses following immunotherapy. Thus, restraining the activation of the immune system in healthy tissues is highly desirable to address this problem. Bioengineering and delivery technologies provide a solution to the issue. In this Review, we first introduce immune-related adverse effects of main immunotherapies and the underlying mechanisms, summarize strategies of designingde bioengineering and delivery systems to reduce their immunotoxicities, and highlight the importance of the development of immunotoxicity-related animal models.

Advances in engineering local drug delivery systems for cancer immunotherapy

Cancer immunotherapy aims to leverage the immune system to suppress the growth of tumors and to inhibit metastasis. The recent promising clinical outcomes associated with cancer immunotherapy have prompted research and development efforts towards enhancing the efficacy of immune checkpoint blockade, cancer vaccines, cytokine therapy, and adoptive T cell therapy. Advancements in biomaterials, nanomedicine, and micro-/nano-technology have facilitated the development of enhanced local delivery systems for cancer immunotherapy, which can enhance treatment efficacy while minimizing toxicity. Furthermore, locally administered cancer therapies that combine immunotherapy with chemotherapy, radiotherapy, or phototherapy have the potential to achieve synergistic antitumor effects. Herein, the latest studies on local delivery systems for cancer immunotherapy are surveyed, with an emphasis on the therapeutic benefits associated with the design of biomaterials and nanomedicines. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Citryl-imine-PEG-ylated chitosan hydrogels - Promising materials for drug delivery applications

The present paper focuses on the synthesis and characterization of new hydrogels and drug delivery systems, designed for local therapy. The hydrogels were obtained by reacting PEG-ylated chitosan derivatives with citral in different molar ratios of their functionalities. The drug delivery systems were obtained by the in situ hydrogelation of PEG-ylated chitosan derivatives with citral, in the presence of a hydrophilic anti-inflammatory drug, diclofenac sodium salt. The hydrogels and the drug delivery systems were characterized from the structural, supramolecular and morphological points of view by FTIR spectroscopy, wide angle X-ray diffraction, polarized optical microscopy and scanning electron microscopy. The in vitro release kinetics of the drug has been monitored in physiological conditions, while the in vivo release was evaluated by the somatic pain model on rats. The in vitro enzymatic degradability of the hydrogels was evaluated in the presence of lysozyme, leading to a significant mass loss of 47% in 21 days. All the findings, recommend the investigated materials as promising candidates for local drug delivery applications.