Physiologically triggered injectable red blood cell-based gel for tumor photoablation and enhanced cancer immunotherapy

A thermoresponsive chitosan-based in situ gel formulation incorporated with 5-FU loaded nanoerythrosomes for fibrosarcoma local chemotherapy

Local administration of drugs at tumor sites over an extended period of time shows potential as a promising approach for cancer treatment. In the present study, the temperature-induced phase transition of chitosan and poloxamer 407 is used to construct an injectable hydrogel encapsulating 5-FU-loaded nanoerythrosome (5-FU-NER-gel). The 5-FU-NERs were found to be spherical, measuring approximately 115 ± 20 nm in diameter and having a surface potential of -7.06 ± 0.4. The drug loading efficiency was approximately 40 %. In situ gel formation took place within 15 s when the gel was exposed to body temperature or subcutaneous injection. A sustained release profile was observed at pH 7.4 and 6.8, with a total 5-FU release of 76.57 ± 4.4 and 98.07 ± 6.31 in 24 h, respectively. MTT, Live/dead, and migration assays confirmed the cytocompatibility of the drug carrier and its effectiveness as a chemotherapeutic formulation. After in vivo antitumor assessment in a subcutaneous autograft model, it was demonstrated that tumor growth inhibition in 14 days was 90 %. Therefore, the obtained injectable chitosan-based hydrogel containing 5-FU-loaded nanoerythrosomes illustrated promising potential as a candidate for local and enhanced delivery of chemotherapeutics at the tumor site.

Nanomedicine Targeting Myeloid-Derived Suppressor Cells Enhances Anti-Tumor Immunity

Cancer immunotherapy, a field within immunology that aims to enhance the host's anti-cancer immune response, frequently encounters challenges associated with suboptimal response rates. The presence of myeloid-derived suppressor cells (MDSCs), crucial constituents of the tumor microenvironment (TME), exacerbates this issue by fostering immunosuppression and impeding T cell differentiation and maturation. Consequently, targeting MDSCs has emerged as crucial for immunotherapy aimed at enhancing anti-tumor responses. The development of nanomedicines specifically designed to target MDSCs aims to improve the effectiveness of immunotherapy by transforming immunosuppressive tumors into ones more responsive to immune intervention. This review provides a detailed overview of MDSCs in the TME and current strategies targeting these cells. Also the benefits of nanoparticle-assisted drug delivery systems, including design flexibility, efficient drug loading, and protection against enzymatic degradation, are highlighted. It summarizes advances in nanomedicine targeting MDSCs, covering enhanced treatment efficacy, safety, and modulation of the TME, laying the groundwork for more potent cancer immunotherapy.

Recent Biomaterial-Assisted Approaches for Immunotherapeutic Inhibition of Cancer Recurrence

Biomaterials possess distinctive properties, notably their ability to encapsulate active biological products while providing biocompatible support. The immune system plays a vital role in preventing cancer recurrence, and there is considerable demand for an effective strategy to prevent cancer recurrence, necessitating effective strategies to address this concern. This review elucidates crucial cellular signaling pathways in cancer recurrence. Furthermore, it underscores the potential of biomaterial-based tools in averting or inhibiting cancer recurrence by modulating the immune system. Diverse biomaterials, including hydrogels, particles, films, microneedles, etc., exhibit promising capabilities in mitigating cancer recurrence. These materials are compelling candidates for cancer immunotherapy, offering in situ immunostimulatory activity through transdermal, implantable, and injectable devices. They function by reshaping the tumor microenvironment and impeding tumor growth by reducing immunosuppression. Biomaterials facilitate alterations in biodistribution, release kinetics, and colocalization of immunostimulatory agents, enhancing the safety and efficacy of therapy. Additionally, how the method addresses the limitations of other therapeutic approaches is discussed.

Immunoactivity of a hybrid membrane biosurface on nanoparticles: enhancing interactions with dendritic cells to augment anti-tumor immune responses

Nano-biointerfaces play a pivotal role in determining the functionality of engineered therapeutic nanoparticles, particularly in the context of designing nanovaccines to effectively activate immune cells for cancer immunotherapy. Unlike involving chemical reactions by conventional surface decorating strategies, cell membrane-coating technology offers a straightforward approach to endow nanoparticles with natural biosurfaces, enabling them to mimic and integrate into the intricate biosystems of the body to interact with specific cells under physiological conditions. In this study, cell membranes, in a hybrid formulation, derived from cancer and activated macrophage cells were found to enhance the interaction of nanoparticles (HMP) with dendritic cells (DCs) and T cells among the mixed immune cells from lymph nodes (LNs), which could be leveraged in the development of nanovaccines for anti-tumor therapy. After loading with an adjuvant (R837), the nanoparticles coated with a hybrid membrane (HMPR) demonstrated effectiveness in priming DCs both in vitro and in vivo, resulting in amplified anti-tumor immune responses compared to those of nanoparticles coated with a single type of membrane or those lacking a membrane coating. The elevated immunoactivity of nanoparticles achieved by incorporating a hybrid membrane biosurface provides us a more profound comprehension of the nano-immune interaction, which may significantly benefit the development of bioactive nanomaterials for advanced therapy.

Photo-Controllable Smart Hydrogels for Biomedical Application: A Review

Nowadays, smart hydrogels are being widely studied by researchers because of their advantages such as simple preparation, stable performance, response to external stimuli, and easy control of response behavior. Photo-controllable smart hydrogels (PCHs) are a class of responsive hydrogels whose physical and chemical properties can be changed when stimulated by light at specific wavelengths. Since the light source is safe, clean, simple to operate, and easy to control, PCHs have broad application prospects in the biomedical field. Therefore, this review timely summarizes the latest progress in the PCHs field, with an emphasis on the design principles of typical PCHs and their multiple biomedical applications in tissue regeneration, tumor therapy, antibacterial therapy, diseases diagnosis and monitoring, etc. Meanwhile, the challenges and perspectives of widespread practical implementation of PCHs are presented in biomedical applications. This study hopes that PCHs will flourish in the biomedical field and this review will provide useful information for interested researchers.

Emerging role of mesenchymal stromal cells in gynecologic cancer therapy

Mesenchymal stromal cells (MSCs) show considerable promise in regenerative medicine with superior anti-fibrotic, immunomodulatory, and angiogenic functions. More recently, discovered with the tumor tropism, MSCs have been exploited as the basis of targeted cancer therapy. In this scenario, MSCs can directly home to tumor tissues and play anti-tumor properties. In addition, MSCs, MSC-derived exosomes and MSC-derived membranes are often developed as carriers for precisely delivering cytotoxic agents to cancer sites, including chemotherapeutic drugs, therapeutic genes, or oncolytic viruses. However, it has revealed the tumorigenic risk of MSCs as an important component within the tumor microenvironment, hampering the translation of MSC-based cancer therapies into clinical settings. Therefore, in this review, we introduce the specific tumor-tropic ability of MSCs and underlying mechanisms. We also summarize the current application of MSC-based therapeutic approaches in treating gynecologic cancers, mainly including cervical, ovarian, and endometrial cancers. Moreover, we discuss the main challenges that the current MSC-based cancer therapies are facing.

Advances in NIR-Responsive Natural Macromolecular Hydrogel Assembly Drugs for Cancer Treatment

Cancer is a serious disease with an abnormal proliferation of organ tissues; it is characterized by malignant infiltration and growth that affects human life. Traditional cancer therapies such as resection, radiotherapy and chemotherapy have a low cure rate and often cause irreversible damage to the body. In recent years, since the traditional treatment of cancer is still very far from perfect, researchers have begun to focus on non-invasive near-infrared (NIR)-responsive natural macromolecular hydrogel assembly drugs (NIR-NMHADs). Due to their unique biocompatibility and extremely high drug encapsulation, coupling with the spatiotemporal controllability of NIR, synergistic photothermal therapy (PTT), photothermal therapy (PDT), chemotherapy (CT) and immunotherapy (IT) has created excellent effects and good prospects for cancer treatment. In addition, some emerging bioengineering technologies can also improve the effectiveness of drug delivery systems. This review will discuss the properties of NIR light, the NIR-functional hydrogels commonly used in current research, the cancer therapy corresponding to the materials encapsulated in them and the bioengineering technology that can assist drug delivery systems. The review provides a constructive reference for the optimization of NIR-NMHAD experimental ideas and its application to human body.

Tumor Vascular Destruction and cGAS-STING Activation Induced by Single Drug-Loaded Nano-Micelles for Multiple Synergistic Therapies of Cancer

Cancer and its metastasis/recurrence still threaten human health, despite various advanced treatments being employed. It is of great significance to develop simple drug formulations to enhance the efficacy and synergistic integration of various monotherapies. Herein, DMXAA, a vasodestructive agent with cGAS-STING stimulation capacity, is integrated with polyethylene glycol grafted poly (lactic-co-glycolic) acid co-polymer (PLGA-PEG), obtaining PLGA-PEG/DMXAA (PPD) nanoparticles to induce the tumor-specific vascular destruction for multiple synergistic therapies of cancer. PPD could induce the formation of blood clots in the tumor after intravenous injection, which subsequently mediate photothermal therapy and further promote the release of oxygen for enhanced radiotherapy. Meanwhile, the enhanced vascular injury can induce perfect starvation therapy of tumor. More importantly, PPD-mediated therapies could trigger potent systemic anti-tumor immunity via inducing the immunogenic death of tumor cells and activating the cGAS-STING pathway. Together with anti-PD-L1, PPD-mediated therapies could not only remove the primary tumors, but also effectively eliminate the distant tumors, metastasis, and recurrence. Therefore, the modulation of tumor composition induced by a single drug-loaded nano-micelle could be utilized to enhance the therapeutic effect of multiple treatments for synergistic and systemic antitumor response, providing a practical strategy for cancer therapy.

Red blood cells: a potential delivery system

Red blood cells (RBCs) are the most abundant cells in the body, possessing unique biological and physical properties. RBCs have demonstrated outstanding potential as delivery vehicles due to their low immunogenicity, long-circulating cycle, and immune characteristics, exhibiting delivery abilities. There have been several developments in understanding the delivery system of RBCs and their derivatives, and they have been applied in various aspects of biomedicine. This article compared the various physiological and physical characteristics of RBCs, analyzed their potential advantages in delivery systems, and summarized their existing practices in biomedicine.

Allomelanin-based biomimetic nanotherapeutics for orthotopic glioblastoma targeted photothermal immunotherapy

Immune checkpoint blockade (ICB) therapy has shown great potential in the treatment of malignant tumors, but its therapeutic effect on glioblastoma (GBM) is unsatisfactory because of the low immunogenicity and T cell infiltration, as well as the presence of blood-brain barrier (BBB) that blocks most of ICB agents to the GBM tissues. Herein, we developed a biomimetic nanoplatform of AMNP@CLP@CCM for GBM-targeted photothermal therapy (PTT) and ICB synergistic therapy by loading immune checkpoint inhibitor CLP002 into the allomelanin nanoparticles (AMNPs) and followed by coating cancer cell membranes (CCM). The resulting AMNP@CLP@CCM can successfully cross the BBB and deliver CLP002 to GBM tissues due to the homing effect of CCM. As a natural photothermal conversion agent, AMNPs are used for tumor PTT. The increased local temperature by PTT not only enhances BBB penetration but also upregulates the PD-L1 level on GBM cells. Importantly, PTT can effectively stimulate immunogenic cell death to induce tumor-associated antigen exposure and promote T lymphocyte infiltration, which can further amplify the antitumor immune responses of GBM cells to CLP002-mediated ICB therapy, resulting in significant growth inhibition of the orthotopic GBM. Therefore, AMNP@CLP@CCM has great potential for the treatment of orthotopic GBM by PTT and ICB synergistic therapy. STATEMENT OF SIGNIFICANCE: The effect of ICB therapy on GBM is limited by the low immunogenicity and insufficient T-cell infiltration. Here we developed a biomimetic nanoplatform of AMNP@CLP@CCM for GBM-targeted PTT and ICB synergistic therapy. In this nanoplatform, AMNPs are used as both photothermal conversion agents for PTT and nanocarriers for CLP002 delivery. PTT not only enhances BBB penetration but also upregulates the PD-L1 level on GBM cells by increasing local temperature. Additionally, PTT also induces tumor-associated antigen exposure and promotes T lymphocyte infiltration to amplify the antitumor immune responses of GBM cells to CLP002-mediated ICB therapy, resulting in significant growth inhibition of the orthotopic GBM. Thus, this nanoplatform holds great potential for orthotopic GBM treatment.

Recent Advances in Hydrogel-Based Phototherapy for Tumor Treatment

Phototherapeutic agent-based phototherapies activated by light have proven to be safe modalities for the treatment of various malignant tumor indications. The two main modalities of phototherapies include photothermal therapy, which causes localized thermal damage to target lesions, and photodynamic therapy, which causes localized chemical damage by generated reactive oxygen species (ROS). Conventional phototherapies suffer a major shortcoming in their clinical application due to their phototoxicity, which primarily arises from the uncontrolled distribution of phototherapeutic agents in vivo. For successful antitumor phototherapy, it is essential to ensure the generation of heat or ROS specifically occurs at the tumor site. To minimize the reverse side effects of phototherapy while improving its therapeutic performance, extensive research has focused on developing hydrogel-based phototherapy for tumor treatment. The utilization of hydrogels as drug carriers allows for the sustained delivery of phototherapeutic agents to tumor sites, thereby limiting their adverse effects. Herein, we summarize the recent advancements in the design of hydrogels for antitumor phototherapy, offer a comprehensive overview of the latest advances in hydrogel-based phototherapy and its combination with other therapeutic modalities for tumor treatment, and discuss the current clinical status of hydrogel-based antitumor phototherapy.

Boosting Checkpoint Immunotherapy with Biomaterials

The immune checkpoint blockade (ICB) therapy has revolutionized the field of cancer treatment, while low response rates and systemic toxicity limit its clinical outcomes. With the rapid advances in nanotechnology and materials science, various types of biomaterials have been developed to maximize therapeutic efficacy while minimizing side effects by increasing tumor antigenicity, reversing immunosuppressive microenvironment, amplifying antitumor immune response, and reducing extratumoral distribution of checkpoint inhibitors as well as enhancing their retention within target sites. In this review, we reviewed current design strategies for different types of biomaterials to augment ICB therapy effectively and then discussed present representative biomaterial-assisted immune modulation and targeted delivery of checkpoint inhibitors to boost ICB therapy. Current challenges and future development prospects for expanding the ICB with biomaterials were also summarized. We anticipate this review will be helpful for developing emerging biomaterials for ICB therapy and promoting the clinical application of ICB therapy.

Erythrocyte-Inspired Functional Materials for Biomedical Applications

Erythrocytes are the most abundant cells in the blood. As the results of long-term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte-inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte-inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte-inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications.

Blood Clot Scaffold Loaded with Liposome Vaccine and siRNAs Targeting PD-L1 and TIM-3 for Effective DC Activation and Cancer Immunotherapy

Tumor vaccines have been showing a relatively weak response rate in cancer patients, while deficiencies in delivery efficiency to dendritic cells (DCs), as well as DC-intrinsic immunosuppressive signals, contribute to a great extent. In this work, we report an implantable blood clot loaded with liposomes-protamine-hyaluronic acid nanoparticles (LPH NPs) containing vaccine (LPH-vaccine) and LPH NPs containing siRNA (LPH-siRNA) for synergistic DC recruitment and activation. The subcutaneously implanted blood clot scaffold can recruit abundant immune cells, particularly DCs, to form a DC-rich environment in vivo. Within the scaffold, LPH-vaccine effectively delivers antigens and adjuvants to the recruited DCs and induces the maturation of DCs. More importantly, LPH-siRNA that targets programmed death-ligand 1 (PD-L1) and T cell immunoglobulin and mucin-containing molecule 3 (TIM-3) can reduce immunosuppressive signals in mature DCs and prevent the DCs from expressing a regulatory program in the scaffold. The activated DCs correlate with an improved magnitude and efficacy of T cell priming, resulting in the production of tumor antigen-specific T cells in multiple mouse models. Our strategy can also be used for patient-tailored therapy by change of tumor neoantigens, suggesting a promising strategy for cancer therapy in the clinic.

Red blood cell-based vaccines for ameliorating cancer chemoimmunotherapy

Immune checkpoint blockade (ICB) therapy has shown promising antitumor effects, but its immune response rate remains unsatisfactory. In recent years, chemotherapy has been proven to have synergistic effects with ICB therapy because some chemotherapeutic agents can enhance the immunogenicity of tumor cells by inducing immunogenic cell death (ICD). However, it cannot be ignored that chemotherapy often shows limited therapeutic efficacy due to high cytotoxicity, drug resistance, and some other side effects. Herein, we report a strategy to improve cancer immunotherapy by utilizing red blood cell-based vaccines (RBC-vaccines) where chemotherapy-induced tumor antigens (cAgs) are anchored onto red blood cells (RBCs) via the EDC/NHS-mediated amine coupling reaction. In this work, RBC-vaccines administered subcutaneously are primarily devoured by dendritic cells (DCs) and significantly improve the efficacy of αPD-1 (anti-programmed cell death 1) treatment by increasing the infiltration of intratumoral CD8⁺ and CD4⁺ T cells and elevating the intratumoral ratio of CD8⁺ T cells to regulatory T cells in the CT-26 colon cancer model. Finally, based on the rejection of tumor rechallenge in cured mice, the combination therapy of RBC-vaccines and αPD-1 can induce the expansion of memory T cells and thereby establish a long-term antitumor immune response. Taken together, the proposed RBC-vaccines have great potential to improve chemoimmunotherapy. STATEMENT OF SIGNIFICANCE: Immunotherapy, especially immune checkpoint blockade therapy, has made great contributions to the treatment of some advanced cancers. Unfortunately, the great majority of patients with cancer do not benefit from immunotherapy. To enhance the response rate of immunotherapy, we developed red blood cell-based vaccines (RBC-vaccines) against cancers where antigens were harvested from chemotherapy-treated cancer cells and then attached to erythrocytes via covalent surface modification. Such RBC-vaccines could provide a wide variety of tumor antigens and damage-associated molecular patterns without the use of any extra ingredients to trigger a stronger antitumor immune response. More importantly, the combination of RBC-vaccines with PD-1 blockade could significantly improve the efficacy of cancer immunotherapy and induce durable antitumor immunity.

Red blood cell membrane nanoparticles for tumor phototherapy

Non-invasive phototherapy includes photodynamic therapy (PDT) and photothermal therapy (PTT), and has garnered special interest in anti-tumor therapy. However, traditional photosensitizers or photothermal agents are faced with major challenges, including easy recognition by immune system, rapid clearance from blood circulation, and low accumulation in target sites. Combining the characteristics of natural cell membrane with the characteristics of photosensitizer or photothermal agent is an important technology to achieve the ideal therapeutic effect of cancer. Red cell membrane (RBMs) coated can disguise phototherapy agents as endogenous substances, thus constructing a new nano bionic therapeutic platform, resisting blood clearance and prolonging circulation time. At present, a variety of phototherapy agents based on Nano-RBMs have been isolated or designed. In this review, firstly, the basic principles of Nano-RBMs and phototherapy are expounded respectively. Then, the latest progress of Nano-RBMs for PDT, PTT and PDT/PTT applications in recent five years has been introduced respectively. Finally, the problems and challenges of Nano-RBMs in the field of phototherapy are put forward.

Ultrasound improved immune adjuvant delivery to induce DC maturation and T cell activation

Tumor immunotherapy has emerged as a promising approach to tumor treatment. Currently, immune adjuvant-based therapeutic modalities are rarely curative in solid tumors owing to challenges including the low permeability and extremely poor water solubility of these adjuvants, limiting their ability to effectively promote dendritic cell (DC) maturation. Herein, we employed ultrasound-mediated cavitation (UMC) to promote the delivery of Toll-like receptor agonist (R837)-loaded pH-responsive liposomes (PEOz-Lip@R837) to tumors. The tumor-associated antigens (TAAs) produced by UMC treatment exhibited vaccinal activity, particularly in the presence of immune adjuvants, together promoting the maturation of DC and inducing cytokine production. Importantly, UMC can down-regulate immune checkpoint molecules, like Cd274, Foxp3 and Ctla4, synergistically stimulating the activation and proliferation of T cells in the body to facilitate tumor treatment. This UMC-enhanced PEOz-Lip@R837 approach was able to induce a robust antitumor immune response capable of arresting primary and distant tumor growth, while also developing immunological memory, protecting against tumor rechallenge following initial tumor clearance. Overall, these results highlight a promising UMC- and pH-sensitive immune adjuvant delivery-based treatment for tumors with the potential for clinical application.

Local scaffold-assisted delivery of immunotherapeutic agents for improved cancer immunotherapy

Cancer immunotherapy, which reprograms a patient's own immune system to eradicate cancer cells, has been demonstrated as a promising therapeutic strategy clinically. Immune checkpoint blockade (ICB) therapies, cytokine therapies, cancer vaccines, and chimeric antigen receptor (CAR) T cell therapies utilize immunotherapy techniques to relieve tumor immune suppression and/or activate cellular immune responses to suppress tumor growth, metastasis and recurrence. However, systemic administration is often hampered by limited drug efficacy and adverse side effects due to nonspecific tissue distribution of immunotherapeutic agents. Advancements in local scaffold-based delivery systems facilitate a controlled release of therapeutic agents into specific tissue sites through creating a local drug reservoir, providing a potent strategy to overcome previous immunotherapy limitations by improving site-specific efficacy and minimizing systemic toxicity. In this review, we summarized recent advances in local scaffold-assisted delivery of immunotherapeutic agents to reeducate the immune system, aiming to amplify anticancer efficacy and minimize immune-related adverse events. Additionally, the challenges and future perspectives of local scaffold-assisted cancer immunotherapy for clinical translation and applications are discussed.

Light-triggered multifunctional nanoplatform for efficient cancer photo-immunotherapy

Cancer immunotherapy is limited by the immune escape of tumor cells and adverse effects. Photo-immunotherapy, the combination of immunotherapy and phototherapy (such as photodynamic therapy (PDT) and photothermal therapy (PTT)), can improve the effectiveness of immunotherapy in cancer treatment. Here, we first explored mesoporous hexagonal core–shell zinc porphyrin-silica nanoparticles (MPSNs), which are composed of a zinc porphyrin core and a mesoporous silica shell, and exhibit high laser-triggered photodynamic and photothermal activity, as well as outstanding drug loading capacity. In other words, MPSNs can be used not only as excellent photosensitizers for photo-immunotherapy, but also as an ideal drug carrier to achieve more efficient synergy. After loading with R837 (imiquimod, a toll-like receptor-7 agonist), MPSNs@R837 will elicit high-efficiency immunogenic cell death via PDT and PTT, and promote dendritic cell maturation after the PH-responsive release of R837, thereby, inducing tumor-specific immune responses. When combined with a programmed death ligand-1 checkpoint blockade, the photo-immunotherapy system markedly restrains primary tumors and metastatic tumors with negligible systemic toxicity. Therefore, the therapeutic strategy of integrating PTT, PDT and checkpoint blockade, shows great potential for suppressing cancer metastasis.

Injectable Erythrocyte Gel Loaded with Bulleyaconitine A for the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease with clinical manifestations including joint cartilage, synovitis, and bone damage. Here we developed an injectable erythrocyte gel loaded with Bulleyaconitine A (BLA) for the treatment of RA and demonstrated its anti-inflammatory effects in vivo and in vitro. In vitro experiments showed that BLA could effectively down-regulate the expression of pro-inflammatory factor in activated macrophages through the nuclear factor-κB (NF-κB) pathway. In vivo experiments have shown that the injection of BLA@RBCs in the inflammatory joints of CIA mice increases the local concentration of BLA in a long time. Improved therapeutic outcomes and reduced toxicity of BLA are demonstrated in our work. Together, the developed BLA@RBCs drug delivery system provides an alternative strategy to treat RA joints and shows high potential in clinical RA treatment.

Locally Injectable Hydrogels for Tumor Immunotherapy

Hydrogel-based local delivery systems provide a good delivery platform for cancer immunotherapy. Injectable hydrogels can directly deliver antitumor drugs to the tumor site to reduce systemic toxicity and achieve low-dose amplification immunotherapy. Therefore, it may overcome the problems of low drug utilization rate and the systemic side effects in cancer immunotherapy through systemic immune drugs, and it provides simple operation and little invasion at the same time. This study aimed to review the research progress of injectable hydrogels in tumor immunotherapy in recent years. Moreover, the local delivery of multiple drugs using injectable hydrogels in tumors is introduced to achieve single immunotherapy, combined chemo-immunotherapy, combined radio-immunotherapy, and photo-immunotherapy. Finally, the application of hydrogels in tumor immunotherapy is summarized, and the challenges and prospects for injectable hydrogels in tumor immunotherapy are proposed.

Effective tumor vessel barrier disruption mediated by perfluoro-N-(4-methylcyclohexyl) piperidine nanoparticles to enhance the efficacy of photodynamic therapy

BACKGROUND

Currently, limited tumor drug permeation, poor oxygen perfusion and immunosuppressive microenvironments are the most important bottlenecks that significantly reduce the efficacy of photodynamic therapy (PDT). The main cause of these major bottlenecks is the platelet activation maintained abnormal tumor vessel barriers. Thus, platelet inhibition may present a new way to most effectively enhance the efficacy of PDT. However, to the best of our knowledge, few studies have validated the effectiveness of such a way in enhancing the efficacy of PDT both in vivo and in vitro. In this study, perfluoro-N-(4-methylcyclohexyl) piperidine-loaded albumin (PMP@Alb) nanoparticles were discovered, which possess excellent platelet inhibition ability. After PMP@Alb treatment, remarkably enhanced intra-tumoral drug accumulation, oxygen perfusion and T cell infiltration could be observed owing to the disrupted tumor vessel barriers. Besides, the effect of ICG@Lip mediated PDT was significantly amplified by PMP@Alb nanoparticles. It was demonstrated that PMP@Alb could be used as a useful tool to improve the efficacy of existing PDT by disrupting tumor vessel barriers through effective platelet inhibition.

Curcumin-Microsphere/IR820 Hybrid Bifunctional Hydrogels for In Situ Osteosarcoma Chemo-co-Thermal Therapy and Bone Reconstruction

Conventional biomaterial-mediated osteosarcoma therapy mainly focuses on its antitumor effect yet often fails to overcome the problem of post-treatment bone tissue defect repair. Simultaneously, minimally invasive drug delivery methods are becoming spotlights for normal tissue preservation. Herein, an injectable curcumin-microsphere/IR820 coloaded hybrid methylcellulose hydrogel (Cur-MP/IR820 gel) platform was designed for osteosarcoma therapy and bone regeneration. In vitro, the K7M2wt osteosarcoma cells were eradicated by hyperthermia and curcumin. Later, the sustained release of curcumin promoted alkaline phosphatase expression and calcium deposition of bone mesenchymal stem cells. In vivo, this hybrid hydrogel could reach tumor site via injection and turned into hydrogel due to heat sensitivity. Under the irradiation of an 808 nm laser, localized hyperthermia (∼51 °C) generated in 5 min to ablate the tumor. Meanwhile, the thermal-accelerated curcumin release and thermal-increased cell membrane permeability led to tumor cell apoptosis. Tumors in photothermal-co-chemotherapy group were successfully restrained from day 2 after treatment. After that, bone reconstruction was promoted because of sustained released curcumin. The chemo-co-thermal efficacy and osteogenic capacity of Cur-MP/IR820 hydrogel suggest a promising approach to the treatment of osteosarcoma and provide provoking inspiration for treating bone tumors and repairing bone tissue.

Construction and evaluation of red blood cells-based drug delivery system for chemo-photothermal therapy

In this study, a novel tumor-targeting drug delivery system (DDS) based on red blood cells (RBCs) were fabricated for combinational chemo-phototherapy against cancer. Cyclic peptide (cRGD) and indocyanine green (ICG) were applied to the surface of RBCs to increase the targeting and photothermal effect, respectively. Doxorubicin (DOX) as a model drug was loaded into RBCs by the hypotonic dialysis method. A series of tests have been carried out to evaluate the RBCs-based DDS and these tasks include physicochemical properties, cellular uptake, targeting ability, and combination therapeutic efficiency. As a result, the DOX was successfully loaded into RBCs and the drug loading amount was 0.84 ± 0.09 mg/mL. There was no significant change of particle size after surface modification of RBCs. The RBCs-based DDS could target to the surface of cancer cells, which delivery DOX to the lesions efficiently and accurately. Meanwhile, due to the combined treatment effect, the RBCs-based DDS can effectively inhibit tumor growth. The RBCs-based DDS constructed in this research may have promising applications in cancer therapy due to their highly synergistic efficient therapy and to investigate its possibility for tumor therapy.