Reactive oxygen species-responsive and Raman-traceable hydrogel combining photodynamic and immune therapy for postsurgical cancer treatment

Smart hydrogel: A new platform for cancer therapy

Cancer is a significant contributor to mortality worldwide, posing a significant threat to human life and health. The unique bioactivity, ability to precisely control drug release, and minimally invasive properties of hydrogels are indispensable attributes that facilitate optimal performance in cancer therapy. However, conventional hydrogels lack the ability to dynamically respond to changes in the surrounding environment, withstand drastic changes in the microenvironment, and trigger drug release on demand. Therefore, this review focuses on smart-responsive hydrogels that are capable of adapting and responding to external stimuli. We comprehensively summarize the raw materials, preparation, and cross-linking mechanisms of smart hydrogels derived from natural and synthetic materials, elucidate the response principles of various smart-responsive hydrogels according to different stimulation sources. Further, we systematically illustrate the important role played by hydrogels in modern cancer therapies within the context of therapeutic principles. Meanwhile, the smart hydrogel that uses machine learning to design precise drug delivery has shown great prospects in cancer therapy. Finally, we present the outlook on future developments and make suggestions for future related work. It is anticipated that this review will promote the practical application of smart hydrogels in cancer therapy and contribute to the advancement of medical treatment.

Co-encapsulated Ce6 + CpG and biopeptide-modified liposomes for enhanced transdermal photo-immunotherapy of superficial tumors

Cancer immunotherapy encounters challenges of a low treatment response rate due to the tumor immunosuppressive microenvironment and immune-related adverse events caused by off-target immunotherapy agents delivered through systemic administration in clinical practice. Photodynamic therapy (PDT) offers a viable approach to improve the immunotherapy efficacy through inducing immunogenic tumor cell death and is particularly advantageous in superficial tumor treatment. Therefore, leveraging integrated nanomaterials for photo-immunotherapy appears to be an ideal strategy to improve therapeutic outcome. In this study, we develop a transdermal-enhancing peptide (TD)-modified cationic liposome that simultaneously encapsulated with photosensitizer chlorine 6 (Ce6) and immunoadjuvant CpG, denoted as Ce6/CpG@Lip-TD, to mediate photo-immunotherapy of superficial tumors via the skin. The functionalization of TD peptide and positively charged surface endow the liposomes enhanced skin penetration capability. The combination of Ce6 and CpG within the liposomes synergistically potentiates the photo-immunotherapy effect when exposed to laser irradiation. In both melanoma and breast cancer murine models, Ce6/CpG@Lip-TD demonstrated substantial tumor-suppressing properties, along with an augmented systemic immune response against distal tumors. As a topical therapeutic agent, Ce6/CpG@Lip-TD circumvents the regulatory challenges associated with the systemic delivery of nanomaterials and significantly reduces systemic side effects, holding great promise for rapid translation into clinical applications.

Spatial-Constraint Modulation of Intra/Extracellular Reactive Oxygen Species by Adaptive Hybrid Materials for Boosting Pyroptosis and Combined Immunotherapy of Breast Tumor

Pyroptosis-immunotherapy has potential for triple-negative breast cancer treatment, but its efficacy is limited by insufficient pyroptosis activation and the need for phased, balanced, and spatially controlled activation of active species during long-term treatment. To reconcile intracellular/extracellular demands in tumor ablation, a nanoparticle-hydrogel hybrid enabling spatiotemporal reactive oxygen species (ROS) modulation is engineered. An open-shell sonosensitizer with unpaired electrons in its molecular orbitals is prepared by chelating Cu2⁺ with TCPP. These sonosensitizers are undergoing bovine serum albumin mediated biomineralization to form calcium phosphate particles and are incorporated into an injectable hydrogel through Schiff base crosslinking between dopamine-functionalized oxidized hyaluronic acid and gallic acid-modified chitosan. After intratumoral injection, nanoparticles endocytosed into tumor cells undergo acidic degradation, releasing calcium ions and GSH-activatable sonosensitizers. Calcium overload synergizes with ultrasound-mediated oxidative stress to induce mitochondrial damage and pyroptosis, while adhesive hydrogels retained in the extracellular matrix control excessive secondary ROS levels to protect oxidation-sensitive entities. This dual-action mechanism enhances the overall therapeutic effect by combining immediate tumor killing with long-term immune activation. This study provides a new route to hybrid material design, addressing the conflicting demands of short-term tumor ablation and long-term immune activation, overcoming the limitations of current pyroptosis-based immunotherapies.

Spatial Configuration-Guided Design of Covalent Organic Framework-Based Artificial Metalloantioxidases for Inhibiting Inflammatory Cascades and Regulating Bone Homeostasis

Intense oxidative stress in bone tissues can trigger the hyperactivation of neutrophils, thereby causing inflammatory cascades to deteriorate bone homeostasis. Here, inspired by the catalytic centers of natural antioxidases, we introduce the spatial configuration-guided design of covalent organic framework (COF)-based artificial metalloantioxidases for inhibiting inflammatory cascades and regulating bone homeostasis. Specifically, the hexaiminohexaazatrinaphthalene COF with ruthenium coordination (S-HACOF-Ru), featuring electron-rich centers with a spatial configuration, demonstrates exceptional antioxidase-like reactive oxygen species (ROS) scavenging capabilities for efficiently mitigating the oxidative stress. As a result, S-HACOF-Ru efficiently prevents the generation of neutrophil extracellular traps and inhibits the release of myeloperoxidase (MPO). By preventing MPO-induced activation of nuclear factor-kappa B and inhibiting proinflammatory macrophage polarization, S-HACOF-Ru successfully blocks the neutrophil-macrophage inflammatory cascades. This intervention promotes bone homeostasis by a shift from bone resorption to tissue regeneration, which can efficiently inhibit alveolar bone loss in periodontal tissues and reverse cartilage damage in ankle joint cavities. We propose that this design strategy provides an intriguing avenue for developing new artificial antioxidases and biocatalytic materials with potential applications in treating a wide range of chronic inflammatory diseases.

X-ray-Induced Photodegradation of Hydrogels by the Incorporation of X-ray-Activated Long Persistent Luminescent Nanoparticles

The development of on-demand degradable hydrogels remains an important challenge. Even though photodegradable hydrogels offer spatiotemporal control over degradation, it is difficult to use ultraviolet, visible, or near-infrared light as a tool for noninvasive triggering in vivo due to the poor tissue-penetration capacity. In contrast, X-ray irradiation can penetrate deep tissue and has virtually no penetration limitations for biological soft tissues. In this study, we propose an X-ray-photodegradation cascade system for hydrogel degradation by incorporating X-ray-activated persistent luminescence nanoparticles (X-PLNPs) into photodegradable hydrogels. A photodegradable 9,10-dialkoxyanthracene-based cross-linker was synthesized and used to prepare photodegradable hydrogels, of which the degradation behavior can be triggered by visible green light. Next, Tb3+-doped β-NaLuF4 was introduced as an X-PLNP that can convert X-rays into visible light centered at 544 nm. The afterglow can even be detected for 4 × 103 s after switching off the X-ray irradiation. The X-ray-induced green light emission was demonstrated to trigger photodegradation of the hydrogel. This proof-of-concept system for X-ray irradiation-induced on-demand hydrogel degradation was used to demonstrate X-ray-sensitive drug delivery inside a chicken breast as the in vitro tissue model. As this X-ray-induced cascade degradation of hydrogels can penetrate deep tissues, it is a promising platform for future in vivo applications requiring on-demand triggered hydrogel degradation, such as drug delivery or removal of hydrogel patches, hydrogel adhesives, or hydrogel tissue engineering scaffolds. It should, however, be noted that the hydrogel's X-ray and photoresponsiveness should be further improved to enable future in vivo use.

Engineered Bacterial Outer Membrane Vesicles Hitchhiking on Neutrophils for Antibody Drug Delivery to Enhance Postoperative Immune Checkpoint Therapy

In clinical practice, surgical removal of tumors often leaves behind small tumors and circulating tumor cells, increasing the risk of metastasis and recurrence, which seriously affects treatment outcomes. Immunotherapy activates the immune system to monitor and inhibit tumor metastasis and recurrence long-term. However, inflammatory microenvironments at surgical sites lead to immunosuppressive tumor-associated macrophages (TAMs), causing immune evasion. Additionally, tumor cells overexpress the immune checkpoint CD47, further weakening the phagocytic and cytotoxic functions of macrophages. Here, the bacterial outer membrane vesicles (OMV) hitchhiking on neutrophils are utilized to precisely deliver immune checkpoint blockade antibodies to the tumor resection site. Escherichia coli is reprogrammed to express CD47 antibody and used to extract CD47 antibody-containing OMV, followed by insertion of Ce6 photosensitizer into the membrane (OC47-Ce6). Purified autologous neutrophils phagocytose and carry OC47-Ce6 for precise targeting to the postoperative tumor resection site, mediating tumor cell killing, aCD47 release, and tumor-associated antigen presentation by light. In vitro and in vivo experiments demonstrate that OC47-Ce6 enhances TAM phagocytic function through TAM polarization and CD47 blockade. This approach effectively activates T-cell anti-tumor immune responses and significantly reduces the risk of postoperative tumor recurrence and metastasis.

Latest advancements and trends in biomedical polymers for disease prevention, diagnosis, treatment, and clinical application

Biomedical polymers are at the forefront of medical advancements, offering innovative solutions in disease prevention, diagnosis, treatment, and clinical use due to their exceptional physicochemical properties. This review delves into the characteristics, classification, and preparation methods of these polymers, highlighting their diverse applications in drug delivery, medical imaging, tissue engineering, and regenerative medicine. We present a thorough analysis of the recent advancements in biomedical polymer research and their clinical applications, acknowledging the challenges that remain, such as immune response management, controlled degradation rates, and mechanical property optimization. Addressing these issues, we explore future directions, including personalization and the integration of nanotechnology, which hold significant potential for further advancing the field. This comprehensive review aims to provide a deep understanding of biomedical polymers and serve as a valuable resource for the development of innovative polymer materials in both fundamental research and clinical practice.

Targeted Raman Visualization and Mitigation of α-Synuclein Amyloidogenesis in Living Zebrafish by a Nanobody-Decorated Polydiacetylene

α-Synuclein (α-Syn) amyloidogenesis is considered a promising diagnostic marker and therapeutic target for Parkinson's disease (PD). Simultaneously visualizing and mitigating α-Syn amyloidogenesis are essential for future PD theranostics, yet they continue to pose an insurmountable challenge. This study have herein developed a nanobody-decorated polydiacetylene to approach a straightforward solution. Grafting α-Syn61-95 segment into the third complementary determining region of a parent nanobody generates an engineered nanobody X30 that can bind with α-Syn and prevent its amyloidogenesis through homotypic interaction. It next use X30 to decorate poly(deca-4,6-diynedioic acid) (PDDA), a polydiacetylene with an ultrastrong alkyne Raman signal (2120 cm-1) in the cellular silent region, to create an α-Syn targeting Raman probe PX30. The binding affinity between X30 and α-Syn can be further boosted for over 150 times attributed to the rigidity of PDDA backbone and the multivalent effect. Therefore, PX30 not only enables real-time Raman visualization of α-Syn amyloidogenesis with a high signal-to-noise ratio in living zebrafish, but also alleviates amyloidogenesis-mediated damage to zebrafish embryos by effectively inhibiting α-Syn amyloidogenesis at low stoichiometric concentrations and scavenging pathologic reactive oxygen species.

Cascade-Responsive Nanoprodrug Disrupts Immune-Fibroblast Communications for Potentiated Cancer Mechanoimmunotherapy

The abnormal tumor mechanical microenvironment due to specific cancer-associated fibroblasts (CAFs) subset and low tumor immunogenicity caused by inefficient conversion of active chemotherapeutic agents are two key obstacles that impede patients with desmoplastic tumors from achieving stable and complete immune responses. Herein, it is demonstrated that FAP-α+CAFs-induced stromal stiffness accelerated tumor progression by precluding cytotoxic T lymphocytes. Subsequently, a cascade-responsive nanoprodrug capable of re-educating FAP-α+CAFs and amplifying tumor immunogenicity for potentiated cancer mechanoimmunotherapy is ingeniously designed. Benefiting from the active targeted release of angiotensin II receptor antagonist (losartan) guided by FAP-α cleavable peptide and the efficient conversion of topoisomerase I inhibitor (7-Ethyl-10-hydroxycamptothecin) prodrug under high glutathione/esterase within tumor cells, this regimen created an immune-activated landscape that retarded primary tumor growth and counteracted resistance to immune checkpoint inhibitor in mice with triple-negative breast cancer. This nanoprodrug-assisted mechanoimmunotherapy can serve as a universal strategy for conferring efficient tumoricidal immunity in "immune excluded" desmoplastic tumor interventions.

PhotoChem Interplays: Lighting the Way for Drug Delivery and Diagnosis

Light, a non-invasive tool integrated with cutting-edge nanotechnologies, has driven transformative advancements in imaging-based diagnosis and drug delivery for cancer and bacterial treatments. This review discusses recent progress in these areas, beginning with emerging imaging technologies. Unlike traditional photosensors activated by visible light, alternative energy sources such as near-infrared (NIR) light, X-rays, and ultrasound have been extensively investigated to activate various photosensors, achieving high sensitivity, wavelength versatility, and spatial resolution for deep-tissue imaging. Moreover, to address challenges like tissue autofluorescence in real-time fluorescence imaging, afterglow luminescent nanoparticles are being developed by integrating these alternative energy sources for real-time imaging and sensing in deep tissue for precise cancer diagnosis and treatment beyond superficial tissues. In addition to deep tissue imaging, light-responsive nanomedicines are revolutionizing anticancer and antimicrobial phototherapy by enabling spatially and temporally controlled drug release. These smart nanoparticles are engineered to release therapeutic cargo at target sites in response to microenvironmental cues specific to tumors or infections. In anticancer phototherapy, these nanoparticles facilitate controlled drug release via photoisomerization, photothermal, and photodynamic processes. To enhance circulation time and specific targeting, biomimetic nanoparticles, which mimic natural anti-tumor responses by our body, have attracted increasing attention. In antimicrobial phototherapy, research has been focused on the chemical modification of the photosensitizer to enable targeted drug delivery. An intriguing strategy has recently emerged involving the development of "pro-photosensitizers" that are specifically activated within bacterial cells upon light irradiation, offering a high margin of safety. These advancements leverage photochemical reactions and nanotechnology to enhance precision therapy and diagnosis in addressing critical health challenges.

All-Small-Molecule Supramolecular Hydrogel Combining Self-Delivery and ROS-Responsive Release for Inhibiting Tumor Growth and Postoperative Recurrence

Supramolecular hydrogels show unprecedented advantages and have attracted widespread attention in biomedical sciences. However, it is challenging for bioactive star molecules, such as celastrol, to meet ideal formation conditions. Here, we report a dynamic covalent method to construct a dihydrol-type celastrol-phenylenediboronic acid-guanosine (DHcelPBG) supramolecular hydrogel. The DHcelPBG hydrogel can effectively accelerate 4T1 cell apoptosis by modulating the PI3K/Akt signaling pathway. Especially, the DHcelPBG hydrogel can serve as a self-delivery platform for reactive oxygen species (ROS)-facilitated self-release. An excessive ROS-containing tumor microenvironment can promote the obtained DHcelPBG hydrogel to kill more 4T1 tumor cells. Meanwhile, the hydrogel also exhibits distinguished degradability and biocompatibility. Subsequently, the orthotopic 4T1 tumor model results further demonstrate that the DHcelPBG hydrogel remarkably inhibits tumor growth and does not damage healthy tissue. In the postoperative recurrence 4T1 tumor model, the DHcelPBG hydrogel also effectively prevents postoperative tumor recurrence and lung metastasis without causing adverse side effects, resulting in an extended lifetime. The DHcelPBG hydrogel also exhibits distinguished degradability and biocompatibility. The DHcelPBG hydrogel integrates ROS-responsiveness, localized self-delivery, and antitumor activity into one system for breast cancer treatment with fewer side effects, showing great potential for clinical transformation in cancer therapy.

Design and advances in antioxidant hydrogels for ROS-induced oxidative disease

Reactive oxygen species (ROS) play a crucial role in human physiological processes, but oxidative stress caused by excessive ROS may lead to a variety of acute and chronic diseases. Despite the development of various strategies and biomaterials, an efficiently and broadly applied method for treatment of ROS-induced oxidative disease remains a bottleneck. Aiming to improve the local oxidative stress environment, numerous bioactive hydrogels with antioxidant properties have emerged and are proven to quickly and continuously eliminate excessive ROS. To deeply understand the design principles and applications of antioxidant hydrogels is highly beneficial for designing antioxidant hydrogels for treatment of oxidative disease. This review provides a detailed summary of recent advances in design and applications of antioxidant hydrogels for various ROS-induced oxidative diseases. In this review, the kinds of antioxidant components in antioxidant hydrogels are outlined in detail. Additionally, the crosslinking methods and the biomedical applications of antioxidant hydrogels are widely summarized and discussed, especially focusing on their usage in different types of diseases and the attention given to the treatment of diseases such as skin wounds, myocardial infarction, and osteoarthritis. Finally, the future development direction of antioxidant hydrogel is further proposed. STATEMENT OF SIGNIFICANCE: Oxidative stress is a pivotal biochemical process that plays a critical role in cellular homeostasis. Excessive cellular oxidative stress triggers an inflammatory response, which is implicated in a spectrum of associated diseases. Given the critical need for managing oxidative stress, antioxidant therapies have become a vital focus in medical research. Hydrogels have garnered substantial interest among biomaterial scientists due to their hydrophilic nature and biocompatibility. The review delves into the realm of antioxidant hydrogels, encompassing the classification of antioxidant components, the synthesis and fabrication of hydrogels, and a comprehensive overview of the biological applications and challenges of these antioxidant hydrogels. Aiming to provide new perspectives for researchers in developing cutting-edge therapeutic approaches that leverage antioxidant hydrogels.

Cancer theragnostics: closing the loop for advanced personalized cancer treatment through the platform integration of therapeutics and diagnostics

Cancer continues to be one of the leading causes of death worldwide, and conventional cancer therapies such as chemotherapy, radiation therapy, and surgery have limitations. RNA therapy and cancer vaccines hold considerable promise as an alternative to conventional therapies for their ability to enable personalized therapy with improved efficacy and reduced side effects. The principal approach of cancer vaccines is to induce a specific immune response against cancer cells. However, a major challenge in cancer immunotherapy is to predict which patients will respond to treatment and to monitor the efficacy of the vaccine during treatment. Theragnostics, an integration of diagnostic and therapeutic capabilities into a single hybrid platform system, has the potential to address these challenges by enabling real-time monitoring of treatment response while allowing endogenously controlled personalized treatment adjustments. In this article, we review the current state-of-the-art in theragnostics for cancer vaccines and RNA therapy, including imaging agents, biomarkers, and other diagnostic tools relevant to cancer, and their application in cancer therapy development and personalization. We also discuss the opportunities and challenges for further development and clinical translation of theragnostics in cancer vaccines.

Photo-Triggered Fluorescence Polyelectrolyte Nanoassemblies: Manipulate and Boost Singlet Oxygen in Photodynamic Therapy

Photodynamic therapy (PDT) is a clinically approved therapeutic modality that has shown great potential for cancer treatment. However, there exist two major problems hindering PDT applications: the nonspecific phototoxicity requiring patients to stay in dark post-PDT, and the limited photodynamic efficiency. Herein, we report a photo-triggered porphyrin polyelectrolyte nanoassembling (photo-triggered PPN) strategy, in which porphyrin photosensitizer and photoswitchable energy accepter are assembled into polyelectrolyte micelles by a combined force of charge interaction and metal-ligand coordination. The polyelectrolyte-based PPN exhibits good biocompatibility, and bestows a unique "confining isolated" inner microenvironment for fully overcoming the π-π stacking of porphyrins with significant photodynamic efficiency (123-fold enhancement). Due to the high Förster resonance energy transfer (FRET) (91.5 %) between porphyrin and photoswitch in closed-form, we could use light as a specific trigger to modulate photoswitch between closed- and open-form, and manipulate the 1O2 generation in three stages: pre-PDT (quenching 1O2 generation), during PDT (activating 1O2 generation), and post-PDT (silencing 1O2 generation). This de novo strategy has for the first time realized remotely manipulating and boosting 1O2 generation in PDT, well resolving the critical and general challenges of limited photodynamic efficiency and side effects from nonspecific phototoxicity.

Biomimetic intelligent nanoplatform with cascade amplification effect for tumor synergy therapy

Tumor heterogeneity, immune-suppressive microenvironment and the precise killing of tumor cells by drugs are important factors affecting tumor treatment. In this study, we developed environment-responsive drug delivery system (FM@IQ/PST&ZIF-8/DOX) based on ZIF-8 for tumor photothermal/immunotherapy/chemotherapy synergistic therapy. The prepared FM@IQ/PST&ZIF-8/DOX nanoplatfrom not only has highly drug loading capacity for chemotherapeutic drug-doxorubicin, but also erythrocyte membrance modified on their surface can endow their immunity-escaping property and prolong their blood circulation time. More important, the neurotransmitter serotonin was encapsulated on the surface of ZIF-8/DOX by oxidative polymerization, which can effectively avoid the premature leakage of DOX in the blood circulation. And the formed polyserotonin shell has superior photothermal conversion performance, as well as the adsorption property of polyserotonin shell was utilized to load imiqumod. When FM@IQ/PST&ZIF-8/DOX entered the tumor tissue, the surface modified folate molecules can specifically bind to the folate receptors on the surface of tumor cells to improve FM@IQ/PST&ZIF-8/DOX uptake by tumor cells. In vitro and in vivo results showed that FM@IQ/PST&ZIF-8/DOX nanoplatform could generate a large amount of heat under near-infrared light irradiation, and then induce the apoptosis of tumor cells, release tumor associated antigens, and effectively solve the problem of tumor heterogeneity. In addition, the loaded imiquimod could effectively improve the immunosuppressive microenvironment, enhance the body's anti-tumor immune response, to inhibit tumor metastasis and recurrence. Therefore, the novel FM@IQ/PST&ZIF-8/DOX nanoplatform designed in this research can not only achieve controllable and precise drug release, but also it is expected to become a promising new strategy for tumor treatment and provide corresponding inspiration for the later research and development of environment-responsive drugs.

A hyaluronic acid-based dual-functional hydrogel microneedle system for sequential melanoma ablation and skin regeneration

Melanoma treatment remains a challenge due to the inadequacy of existing clinical approaches and the difficulty of tissue regeneration. Recently, microneedles have been widely studied in tumor therapy and skin repair. Hence, a hyaluronic acid (HA)-based dual-functional hydrogel microneedle (MN) system was constructed to sequentially achieve tumor ablation and skin regeneration. Carbon nanotubes@calcium peroxide@tannic acid-Fe/chlorin e6 (CCa@TF/Ce6) nanomaterial was encapsulated in dissolvable polyvinyl alcohol/polyvinylpyrrolidone tips and accurately released to the tumor site to suppress melanoma via the photothermal and photodynamic therapies under the dual laser irradiation due to the generation of reactive oxygen species (ROS) and heat. Particularly, ROS and heat triggered immunogenic cell death, promoted dendritic cells maturation and reshaped the tumor-associated macrophage phenotype from the protumor M2 phenotype to the anti-tumor M1 phenotype, ultimately activating autoimmunity to eliminate the tumor. Following tumor ablation, the MN base accelerated skin regeneration owing to HB-PVA hydrogel through reducing oxidative stress, promoting cell proliferation and facilitating cell migration. Overall, the dual-functional hydrogel MN designed in this study, offers a new avenue for sequential melanoma combination treatment and skin regeneration.

Hydrogel local drug delivery systems for postsurgical management of tumors: Status Quo and perspectives

Surgery is one of the primary treatments for solid tumors. However, the incomplete resection of tumor cells and the immunosuppressive microenvironment make the issue of postsurgical tumor recurrence a great challenge. Furthermore, a wide range of requirements, including ensuring effective hemostasis, implementing prophylactic measures against infection, and promoting wound healing, were also raised in the postsurgical management of tumors. To fulfill these demands, multiple hydrogel local drug delivery systems (HLDDS) were developed recently. These HLDDS are expected to offer numerous advantages in the postsurgical management of tumors, such as achieving high local drug concentrations at the lesion, efficient delivery to surgical microcavities, mitigating systemic side effects, and addressing the diverse demand. Thus, in this review, a detailed discussion of the diverse demands of postsurgical management of tumors is provided. And the current publication trend on HLDDS in the postsurgical management of tumors is analyzed and discussed. Then, the applications of different types of HLDDS, in-situ HLDDS and non-in-situ HLDDS, in postsurgical management of tumors were introduced and summarized. Besides, the current problems and future perspectives are discussed. The review is expected to provide an overview of HLDDS in postsurgical management of tumors and promote their clinical application.

Recent advances in reactive oxygen species (ROS)-responsive drug delivery systems for photodynamic therapy of cancer

Reactive oxygen species (ROS)-responsive drug delivery systems (DDSs) have garnered significant attention in cancer research because of their potential for precise spatiotemporal drug release tailored to high ROS levels within tumors. Despite the challenges posed by ROS distribution heterogeneity and endogenous supply constraints, this review highlights the strategic alliance of ROS-responsive DDSs with photodynamic therapy (PDT), enabling selective drug delivery and leveraging PDT-induced ROS for enhanced therapeutic efficacy. This review delves into the biological importance of ROS in cancer progression and treatment. We elucidate in detail the operational mechanisms of ROS-responsive linkers, including thioether, thioketal, selenide, diselencide, telluride and aryl boronic acids/esters, as well as the latest developments in ROS-responsive nanomedicines that integrate with PDT strategies. These insights are intended to inspire the design of innovative ROS-responsive nanocarriers for enhanced cancer PDT.

A microenvironment-modulating dressing with proliferative degradants for the healing of diabetic wounds

Diabetic wounds are usually entangled in a disorganized and self-perpetuating microenvironment and accompanied by a prolonged delay in tissue repair. Sustained and coordinated microenvironment regulation and tissue regeneration are key to the healing process of diabetic wounds, yet they continue to pose a formidable challenge. Here we report a rational double-layered dressing design based on chitosan and a degradable conjugated polymer polydiacetylene, poly(deca-4,6-diynedioic acid) (PDDA), that can meet this intricate requirement. With an alternating ene-yne backbone, PDDA degrades when reacting with various types of reactive oxygen species (ROS), and more importantly, generates proliferative succinic acid as a major degradant. Inheriting from PDDA, the developed PDDA-chitosan double layer dressing (PCD) can eliminate ROS in the microenvironment of diabetic wounds, alleviate inflammation, and downregulate gene expression of innate immune receptors. PCD degradation also triggers simultaneous release of succinic acid in a sustainable manner, enabling long-term promotion on tissue regeneration. We have validated the biocompatibility and excellent performance of PCD in expediting the wound healing on both diabetic mouse and porcine models, which underscores the significant translational potential of this microenvironment-modulating, growth-promoting wound dressing in diabetic wounds care.

pH factors in chronic wound and pH-responsive polysaccharide-based hydrogel dressings

Chronic wounds present a significant healthcare challenge marked by complexities such as persistent bleeding, inhibited cell proliferation, dysregulated inflammation, vulnerability to infection, and compromised tissue remodeling. Conventional wound dressings often prove inadequate in addressing the intricate requirements of chronic wound healing, leading to slow healing and heightened susceptibility to infections in patients with prolonged medical conditions. Bacterial biofilms in chronic wounds pose an additional challenge due to drug resistance. Advanced wound dressings have emerged as promising tools in expediting the healing process. Among these, pH-responsive polysaccharide-based hydrogels exhibit immense prospect by adapting their functions to dynamic wound conditions. Despite their potential, the current literature lacks a thorough review of these wound dressings. This review bridges this gap by meticulously examining factors related to chronic wounds, current strategies for healing, and the mechanisms and potential applications of pH-responsive hydrogel wound dressings as an emerging therapeutic solution. Special focus is given to their remarkable antibacterial properties and significant self-healing abilities. It further explores the pH-monitoring functions of these dressings, elucidating the associated pH indicators. This synthesis of knowledge aims to guide future research and development in the field of pH-responsive wound dressings, providing valuable insights into their potential applications in wound care.

Salvaging myocardial infarction with nanoenzyme-loaded hydrogels: Targeted scavenging of mitochondrial reactive oxygen species

Myocardial infarction resulting from coronary artery atherosclerosis is the leading cause of heart failure, which represents a significant global health burden. The limitations of conventional pharmacologic thrombolysis and flow reperfusion procedures highlight the urgent need for new therapeutic strategies to effectively treat myocardial infarction. In this study, we present a novel biomimetic approach that integrates polyphenols and metal nanoenzymes, inspired by the structure of pomegranates. We developed tannic acid-coated Mn-Co3O4 (MCT) nanoparticles in combination with an injectable collagen hydrogel for the effective treatment of myocardial infarction. The hydrogel enhanced the infarct microenvironment, while the slow-released MCT targets mitochondria to inhibit the post-infarction surge of reactive oxygen species, providing anti-apoptotic and anti-inflammatory effects. RNA sequencing revealed the potential of hydrogels to serve as an interventional mechanism during the post-infarction inflammatory phase. Notably, we found that the hydrogel, when combined with the nanopomegranate-based therapy, significantly improves adverse ventricular remodeling and restores cardiac function in early infarction management. The MCT hydrogel leverages the unique benefits of both MCT nanopomegranates and collagen, demonstrating a synergistic effect. This approach provides a promising example of the potential cooperation between nanomimetic structures and natural biomaterials in therapeutic applications.

Intelligent Hydrogel-Assisted Hepatocellular Carcinoma Therapy

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

Injectable Therapeutic Hydrogel with H2O2 Self-Supplying and GSH Consumption for Synergistic Chemodynamic/Low-Temperature Photothermal Inhibition of Postoperative Tumor Recurrence and Wound Infection

Postoperative tumor recurrence and wound infection remain significant clinical challenges in surgery, often requiring adjuvant therapies. The combination treatment of photothermal therapy (PTT) and chemodynamic therapy (CDT) has proven to be effective in cancer treatment and wound infection. However, the hyperthermia during PTT increases the risk of normal tissue damage, severely impeding its application. Moreover, the efficacy of CDT is limited by insufficient hydrogen peroxide (H2O2) and excessive glutathione (GSH) levels at tumor or infection sites. Herein, an injectable and multifunctional CuO2@Au hydrogel system (CuO2@Au Gel) is developed for synergistic CDT and low-temperature PTT (LTPTT) to prevent tumor recurrence and bacterial wound infections. CuO2@Au Gel is constructed by embedding therapeutic CuO2@Au into low-melting point agarose hydrogel. In vitro and in vivo experiments confirm that the CuO2@Au in CuO2@Au Gel is capable of self-supplying H2O2 and depleting GSH, exhibiting effective CDT effect in acidic tumor or bacterial infected microenvironment. Additionally, it exhibits favorable photothermal conversion ability, inducing localized temperature elevation and synergistically enhancing CDT efficiency. The prepared CuO2@Au Gel demonstrates efficient tumor ablation capability in post-surgery recurrence mouse models and exhibits promising anti-infective efficiency in bacterial infection wound models, indicating significant potential in adjuvant therapy for post-surgical treatment and recovery.

In situ engineered magnesium alloy implant for preventing postsurgical tumor recurrence

Invasive tumors are difficult to be completely resected in clinical surgery due to the lack of clear resection margins, which greatly increases the risk of postoperative recurrence. However, chemotherapy and radiotherapy as the traditional means of postoperative adjuvant therapy, are limited in postoperative applications, such as multi-drug resistance and low sensitivity, etc. Therefore, an engineered magnesium alloy rod is designed as a postoperative implant to completely remove postoperative residual tumor tissue and inhibit tumor recurrence by gas and mild magnetic hyperthermia therapy (MMHT). As a reactive metal, magnesium alloy responds to the acidic tumor microenvironment by continuously generating hydrogen. The in-situ generation of hydrogen not only protects the surrounding normal tissue, but also enables the magnesium alloy to achieve MMHT under low-intensity alternating magnetic field (AMF). Furthermore, the numerous reactive oxygen species (ROS) produced by heat stress will combine with nitric oxide (NO) generated in situ, to produce more toxic reactive nitrogen species (RNS) storm. In summary, engineered magnesium alloy can completely remove residual tumor tissue and inhibit tumor recurrence by MMHT and RNS storm under low-intensity AMF, and the biodegradability of magnesium alloy makes great potential for clinical application.

Potential of Resveratrol to Combine with Hydrogel for Photodynamic Therapy against Bacteria and Cancer-A Review

Bacterial infections and cancers are important issues in public health around the world. Currently, Western medicine is the most suitable approach when dealing with these issues. "Antibiotics" and "Corticosteroids" are the Western medicines used for bacterial infection. "Chemotherapy drugs", "surgery", and "radiotherapy" are common techniques used to treat cancer. These are conventional treatments with many side effects. PDT is a non-invasive and effective therapy for bacterial infection and cancer diseases.

METHODS

Nine electronic databases, namely WanFang Data, PubMed, Science Direct, Scopus, Web of Science, Springer Link, SciFinder, and China National Knowledge Infrastructure (CNKI), were searched to conduct this literature review, without any regard to language constraints. Studies focusing on the photodynamic actions of hydrogel and Resveratrol were included that evaluated the effect of PDT against bacteria and cancer. All eligible studies were analyzed and summarized in this review.

RESULTS

Resveratrol has antibacterial and anticancer effects. It can also act as PS in PDT or adjuvant but has some limitations. This is much better when combined with a hydrogel to enhance the effectiveness of PDT in the fight against bacteria and cancer.

CONCLUSIONS

Resveratrol combined with hydrogel is possible for PDT treatment in bacteria and cancer. They are compatible and reinforce each other to increase the effectiveness of PDT. However, much more work is required, such as cytotoxicity safety assessments of the human body and further enhancing the effectiveness of PDT in different environments for future investigations.

Control nucleation for strong and tough crystalline hydrogels with high water content

Hydrogels, provided that they integrate strength and toughness at desired high content of water, promise in load-bearing tissues such as articular cartilage, ligaments, tendons. Many developed strategies impart hydrogels with some mechanical properties akin to natural tissues, but compromise water content. Herein, a strategy deprotonation-complexation-reprotonation is proposed to prepare polyvinyl alcohol hydrogels with water content as high as ~80% and favorable mechanical properties, including tensile strength of 7.4 MPa, elongation of around 1350%, and fracture toughness of 12.4 kJ m-2. The key to water holding yet improved mechanical properties lies in controllable nucleation for refinement of crystalline morphology. With nearly constant water content, mechanical properties of as-prepared hydrogels are successfully tailored by tuning crystal nuclei density via deprotonation degree and their distribution uniformity via complexation temperature. This work provides a nucleation concept to design robust hydrogels with desired water content, holding implications for practical application in tissue engineering.

Hippophae Rhamnoides-derived Phytomedicine Nano-System Modulates Bax/Fas Pathways to Reduce Proliferation in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most common primary tumor of the breast with limited effectual drug availability. Therefore, the aim of the study is to develop an innovative phyto-nanomedicine (PNM) to cure TNBC with the least genotoxicity. Hereinafter, the sea buckthorn' extracted polyphenols (SBP), combine with metformin (MET), are synthesized as a novel PNM to evaluate its anti-tumor properties, effectiveness, and mechanism of action in TNBC in vitro and in vivo models. The SBP exhibits 16 new kinds of polyphenols that are been reported earlier which regulated cell development, proliferation, and programmed cell death (PCD) effectively. SBP-MET PNM inhibits MDA-MB-231 (47%), MDA-MB-436 (46%), and 4T1 (46%) cell proliferation but does not affect L929 normal murine cell development and successfully induce PCD (73.19%) in MDA-MB-231 cells. Mechanistically, in vivo SBP-MET proteome expression profiling reveals upregulation of proapoptotic Bax protein and activation of Fas signaling pathways convince downstream Daxx and FADD proteins, which further triggers Caspase-3 that prompts apoptosis in human TNBC cells by cleaving PARP-1 protein. Current findings establish innovative highly biocompatible phyto-nanomedicine that has significant potential to inhibit TNBC cell growth and induce regulated cell death (RCD) in vivo model, thereby opening a new arena for TNBC therapy.

ROS-responsive hydrogels: from design and additive manufacturing to biomedical applications

Hydrogels with intricate 3D networks and high hydrophilicity have qualities resembling those of biological tissues, making them ideal candidates for use as smart biomedical materials. Reactive oxygen species (ROS) responsive hydrogels are an innovative class of smart hydrogels, and are cross-linked by ROS-responsive modules through covalent interactions, coordination interactions, or supramolecular interactions. Due to the introduction of ROS response modules, this class of hydrogels exhibits a sensitive response to the oxidative stress microenvironment existing in organisms. Simultaneously, due to the modularity of the ROS-responsive structure, ROS-responsive hydrogels can be manufactured on a large scale through additive manufacturing. This review will delve into the design, fabrication, and applications of ROS-responsive hydrogels. The main goal is to clarify the chemical principles that govern the response mechanism of these hydrogels, further providing new perspectives and methods for designing responsive hydrogel materials.

Nanoparticles destabilizing the cell membranes triggered by NIR light for cancer imaging and photo-immunotherapy

Cationic polymers have great potential for cancer therapy due to their unique interactions with cancer cells. However, their clinical application remains limited by their high toxicity. Here we show a cell membrane-targeting cationic polymer with antineoplastic activity (Pmt) and a second near-infrared (NIR-II) fluorescent biodegradable polymer with photosensitizer Bodipy units and reactive oxygen species (ROS) responsive thioketal bonds (PBodipy). Subsequently, these two polymers can self-assemble into antineoplastic nanoparticles (denoted mt-NPBodipy) which could further accumulate at the tumor and destroy cell membranes through electrostatic interactions, resulting in cell membrane destabilization. Meanwhile, the photosensitizer Bodipy produces ROS to induce damage to cell membranes, proteins, and DNAs to kill cancer cells concertedly, finally resulting in cell membrane lysis and cancer cell death. This work highlights the use of near-infrared light to spatially and temporarily control cationic polymers for photodynamic therapy, photo-immunotherapy, and NIR-II fluorescence for bio-imaging.

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.

Boosting Checkpoint Immunotherapy with Biomimetic Nanodrug Delivery Systems

Immune checkpoint blockade (ICB) has achieved unprecedented progress in tumor immunotherapy by blocking specific immune checkpoint molecules. However, the high biodistribution of the drug prevents it from specifically targeting tumor tissues, leading to immune-related adverse events. Biomimetic nanodrug delivery systems (BNDSs) readily applicable to ICB therapy have been widely developed at the preclinical stage to avoid immune-related adverse events. By exploiting or mimicking complex biological structures, the constructed BNDS as a novel drug delivery system has good biocompatibility and certain tumor-targeting properties. Herein, the latest findings regarding the aforementioned therapies associated with ICB therapy are highlighted. Simultaneously, prospective bioinspired engineering strategies can be designed to overcome the four-level barriers to drug entry into lesion sites. In future clinical translation, BNDS-based ICB combination therapy represents a promising avenue for cancer treatment.

Regulation of CTLs/Tregs via Highly Stable and Ultrasound-Responsive Cerasomal Nano-Modulators for Enhanced Colorectal Cancer Immunotherapy

Immunotherapy is showing good potential for colorectal cancer therapy, however, low responsive rates and severe immune-related drug side effects still hamper its therapeutic effectiveness. Herein, a highly stable cerasomal nano-modulator (DMC@P-Cs) with ultrasound (US)-controlled drug delivery capability for selective sonodynamic-immunotherapy is fabricated. DMC@P-Cs' lipid bilayer is self-assembled from cerasome-forming lipid (CFL), pyrophaeophorbid conjugated lipid (PL), and phospholipids containing unsaturated chemical bonds (DOPC), resulting in US-responsive lipid shell. Demethylcantharidin (DMC) as an immunotherapy adjuvant is loaded in the hydrophilic core of DMC@P-Cs. With US irradiation, reactive oxygen species (ROS) can be effectively generated from DMC@P-Cs, which can not only kill tumor cells for inducing immunogenic cell death (ICD), but also oxidize unsaturated phospholipids-DOPC to change the permeability of the lipid bilayers and facilitate controlled release of DMC, thus resulting in down-regulation of regulatory T cells (Tregs) and amplification of anti-tumor immune responses. After intravenous injection, DMC@P-Cs can efficiently accumulate at the tumor site, and local US treatment resulted in 94.73% tumor inhibition rate. In addition, there is no detectable systemic toxicity. Therefore, this study provides a highly stable and US-controllable smart delivery system to achieve synergistical sonodynamic-immunotherapy for enhanced colorectal cancer therapy.

How to optimize the immune checkpoint blockade therapy for cancers?

The realm of cancer therapy has been profoundly altered with the emergence of immune checkpoint blockade (ICB) therapy, providing improved survival prospects for many patients with some cancers. However, the challenge of achieving efficient or sustained therapeutic benefits underscores the critical imperative to optimize ICB strategies. This review elucidates the pivotal role of predictive biomarkers in optimizing precision ICB therapy, deciphering the intricate dynamics associated with the response heterogeneity. Furthermore, it critically examines the application of nanotechnology-driven drug delivery as a promising avenue to amplify ICB efficacy, facilitating controlled and targeted drug release. Recognizing the comprehensive and dynamic interplay among tumor cells, immune cells, and stromal cells has catalyzed the transformative advances in reverse translational research. This approach enables researchers to gain insights into the underlying mechanisms of ICB therapy, therapeutic responses, and resistance mechanisms. The convergence of predictive biomarkers, revolutionary nanotechnology, and reverse translational research emerges as an indispensable focal point, propelling the frontiers of precision oncology within the complex landscape of ICB therapy.

Fine-tuning of stable organic free-radical photosensitizers for photodynamic immunotherapy

Photodynamic immunotherapy (PDI) is an innovative approach to cancer treatment that utilizes photodynamic therapy (PDT) and photosensitizers (PSs) to induce immunogenic cell death (ICD). However, currently most commonly used PSs have restricted capabilities to generate reactive oxygen species (ROS) via a type-II mechanism under hypoxic environments, which limits their effectiveness in PDI. To overcome this, we propose a novel approach for constructing oxygen independent PSs based on stable organic free-radical molecules. By fine-tuning the characteristics of tris(2,4,6-trichlorophenyl)-methyl (TTM) radicals through the incorporation of electron-donating moieties, we successfully found that TTMIndoOMe could produce substantial amounts of ROS even in hypoxic environments. In vitro experiments showed that TTMIndoOMe could effectively produce O2˙-, kill tumor cells and trigger ICD. Moreover, in vivo experiments also demonstrated that TTMIndoOMe could further trigger anti-tumor immune response and exhibit a superior therapeutic effect compared with PDT alone. Our study offers a promising approach towards the development of next-generation PSs functioning efficiently even under hypoxic conditions and also paves the way for the creation of more effective PSs for PDI.

Turning Threat to Therapy: A Nanozyme-Patch in Surgical Bed for Convenient Tumor Vaccination by Sustained In Situ Catalysis

Complete surgical resection of tumor is difficult as the invasiveness of cancer, making the residual tumor a lethal threat to patients. The situation is deteriorated by the immune suppression state after surgery, which further nourishes tumor recurrence and metastasis. Immunotherapy is promising to combat tumor metastasis, but is limited by severe toxicity of traditional immunostimulants and complexity of multiple functional units. Here, it is reported that the simple "trans-surgical bed" delivery of Cu2- xSe nanozyme (CSN) by a microneedle-patch can turn the threat to therapy by efficient in situ vaccination. The biocompatible CSN exhibits both peroxidase and glutathione oxidase-like activities, efficiently exhausting glutathione, boosting free radical generation, and inducing immunogenic cell death. The once-for-all inserting of the patch on surgical bed facilitates sustained catalytic action, leading to drastic decrease of recurrence rate and complete suppression of tumor-rechallenge in cured mice. In vivo mechanism interrogation reveals elevated cytotoxic T cell infiltration, re-educated macrophages, increased dendritic cell maturation, and memory T cells formation. Importantly, preliminary metabolism and safety evaluation validated that the metal accumulation is marginable, and the important biochemical indexes are in normal range during therapy. This study has provided a simple, safe, and robust tumor vaccination approach for postsurgical metastasis control.

Carbon-Iodine Polydiacetylene Nanofibers for Image-Guided Radiotherapy and Tumor-Microenvironment-Enhanced Radiosensitization

Radiotherapy is a mainstay treatment used in clinics for locoregional therapy, although it still represents a great challenge to improve the sensitivity and accuracy of radiotherapy for tumors. Here, we report the conjugated polymer, polydiiododiacetylene (PIDA), with an iodine content of 84 wt %, as a highly effective computed tomography (CT) contrast agent and tumor microenvironment-responsive radiosensitizer. PIDA exhibited several key properties that contribute to the improvement of precision radiotherapy. The integrated PIDA nanofibers confined within the tumor envelope demonstrated amplified CT intensity and prolonged retention, providing an accurate calculation of dose distribution and precise radiation delivery for CT image-guided radiotherapy. Therefore, our strategy pioneers PIDA nanofibers as a bridge to cleverly connect a fiducial marker to guide accurate radiotherapy and a radiosensitizer to improve tumor sensitivity, thereby minimizing potential damage to surrounding tissues and facilitating on-demand therapeutic intervention in tumors.

A Silver-Induced Absorption Red-Shifted Dual-Targeted Nanodiagnosis-Treatment Agent for NIR-II Photoacoustic Imaging-Guided Photothermal and ROS Simultaneously Enhanced Immune Checkpoint Blockade Antitumor Therapy

Tumor metastasis remains a leading factor in the failure of cancer treatments and patient mortality. To address this, a silver-induced absorption red-shifted core-shell nano-particle is developed, and surface-modified with triphenylphosphonium bromide (TPP) and hyaluronic acid (HA) to obtain a novel nanodiagnosis-treatment agent (Ag@CuS-TPP@HA). This diagnosis-treatment agent can dual-targets cancer cells and mitochondria, and exhibits maximal light absorption at 1064 nm, thereby enhancing nesr-infrared II (NIR-II) photoacoustic (PA) signal and photothermal effects under 1064 nm laser irradiation. Additionally, the silver in Ag@CuS-TPP@HA can catalyze the Fenton-like reactions with H2 O2 in the tumor tissue, yielding reactive oxygen species (ROS). The ROS production, coupled with enhanced photothermal effects, instigates immunogenic cell death (ICD), leading to a substantial release of tumor-associated antigens (TAAs) and damage-associated molecular patterns, which have improved the tumor immune suppression microenvironment and boosting immune checkpoint blockade therapy, thus stimulating a systemic antitumor immune response. Hence, Ag@CuS-TPP@HA, as a cancer diagnostic-treatment agent, not only accomplishes targeted the NIR-II PA imaging of tumor tissue and addresses the challenge of accurate diagnosis of deep cancer tissue in vivo, but it also leverages ROS/photothermal therapy to enhance immune checkpoint blockade, thereby eliminating primary tumors and effectively inhibiting distant tumor growth.

Antimicrobial research of carbohydrate polymer- and protein-based hydrogels as reservoirs for the generation of reactive oxygen species: A review

Reactive oxygen species (ROS) play an important role in biological milieu. Recently, the rapid growth in our understanding of ROS and their promise in antibacterial applications has generated tremendous interest in the combination of ROS generators with bulk hydrogels. Hydrogels represent promising supporters for ROS generators and can locally confine the nanoscale distribution of ROS generators whilst also promoting cellular integration via biomaterial-cell interactions. This review highlights recent efforts and progress in developing hydrogels derived from biological macromolecules with embedded ROS generators with a focus on antimicrobial applications. Initially, an overview of passive and active antibacterial hydrogels is provided to show the significance of proper hydrogel selection and design. These are followed by an in-depth discussion of the various approaches for ROS generation in hydrogels. The structural engineering and fabrication of ROS-laden hydrogels are given with a focus on their biomedical applications in therapeutics and diagnosis. Additionally, we discuss how a compromise needs to be sought between ROS generation and removal for maximizing the efficacy of therapeutic treatment. Finally, the current challenges and potential routes toward commercialization in this rapidly evolving field are discussed, focusing on the potential translation of laboratory research outcomes to real-world clinical outcomes.

Photonic control of image-guided ferroptosis cancer nanomedicine

Photonic nanomaterials, characterized by their remarkable photonic tunability, empower a diverse range of applications, including cutting-edge advances in cancer nanomedicine. Recently, ferroptosis has emerged as a promising alternative strategy for effectively killing cancer cells with minimizing therapeutic resistance. Novel design of photonic nanomaterials that can integrate photoresponsive-ferroptosis inducers, -diagnostic imaging, and -synergistic components provide significant benefits to effectively trigger local ferroptosis. This review provides a comprehensive overview of recent advancements in photonic nanomaterials for image-guided ferroptosis cancer nanomedicine, offering insights into their strengths, constraints, and their potential as a future paradigm in cancer treatment.

The role of ROS in tumor infiltrating immune cells and cancer immunotherapy

Reactive oxygen species (ROS) are a group of short-lived highly reactive molecules formed intracellularly from molecular oxygen. ROS can alter biochemical, transcriptional, and epigenetic programs and have an indispensable role in cellular function. In immune cells, ROS are mediators of specialized functions such as phagocytosis, antigen presentation, activation, cytolysis, and differentiation. ROS have a fundamental role in the tumor microenvironment (TME) where they are produced by immune cell-intrinsic and -extrinsic mechanisms. ROS can act as a double-edged sword with short exposures leading to activation in various innate and adaptative immune cells, and prolonged exposures, unopposed by redox balancing antioxidants leading to exhaustion, immunosuppression, and unresponsiveness to cancer immunotherapy. Due to its plasticity and impact on the anti-tumor function of immune cells, attempts are currently in process to harness ROS biology with the purpose to improve contemporary strategies of cancer immunotherapy. Here, we provide a short overview how ROS and various antioxidant systems impact on the function of innate and adaptive immune system cells with emphasis on the TME and immune-based therapies for cancer.

A hydrogel optical fibre sensor for rapid on-site ethanol determination

Ethanol plays a critical role in the modern chemical industry, food production, and medical research. Given its wide applications, the detection of ethanol concentration is very necessary. In this paper, a fibre device for rapid ethanol detection is proposed. The sensing head was fabricated with multimode fibre. The hydrogel was photo-cured on the fibre tip from polyethylene glycol diacrylate (PEGDA). In the hydrogel, rhodamine 6G (R6G) was immobilized as the fluorescent indicator. The sensor was designed based on the swelling behaviour of the hydrogel in liquid. The transparency of the hydrogel was modulated by the component of the water-ethanol mixture, thus, the fluorescence intensity of R6G was monitored for the determination of ethanol. Within the range of 0-62.2 vol%, the detection limit (LOD) was 0.4 vol%. A detailed comparison with other detection methods showed that the proposed sensor has the advantages of being single-ended, low LOD, cost-effective, and easy to prepare. It has great potential for on-site ethanol detection applications.

Injectable Zwitterionic Physical Hydrogel with Enhanced Chemodynamic Therapy and Tumor Microenvironment Remodeling Properties for Synergistic Anticancer Therapy

Surgical resection is the first-line therapy for breast cancer. However, residual tumor cells and the highly immunosuppressive tumor microenvironment (TME) continue to have a serious impact on tumor recurrence and metastasis postresection. Implantation of an in situ hydrogel system postresection has shown to be an effective treatment with great clinical potential. Herein, an injectable zwitterionic hydrogel system was developed for local drug delivery with enhanced immune activation and prevention of tumor recurrence. Driven by electrostatic interactions, poly(sulfobetaine methacrylate) (PSBMA) self-assembles into a hydrogel in saline, achieving low protein adsorption and tunable biodegradability. The chemotherapy drug doxorubicin (DOX) was loaded into copper peroxide nanoparticles (CuO2/DOX), which were coated with macrophage membranes to form tumor-targeting nanoparticles (M/CuO2/DOX). Next, M/CuO2/DOX and the stimulator of interferon genes (STING) agonist 2',3'-cGAMP were coloaded into PSBMA hydrogel (Gel@M/CuO2/DOX/STING). The hydrophilic STING agonist was first released by diffusion from hydrogel to activate the STING pathway and upregulate interferon (IFN) signaling related genes, remodeling the immunosuppressive TME. Then, M/CuO2/DOX targeted the residual tumor cells, combining with DOX-induced DNA damage, immunogenic tumor cell death, and copper death. Hence, this work combines chemodynamic therapy with STING pathway activation in TME, encouraging residual tumor cell death, promoting the maturation of dendritic cells, enhancing tumor-specific CD8+ T cell infiltration, and preventing postoperative recurrence and metastasis.

Stimuli-Responsive Polymer-Based Nanosystems for Cancer Theranostics

Stimuli-responsive polymers can respond to internal stimuli, such as reactive oxygen species (ROS), glutathione (GSH), and pH, biological stimuli, such as enzymes, and external stimuli, such as lasers and ultrasound, etc., by changing their hydrophobicity/hydrophilicity, degradability, ionizability, etc., and thus have been widely used in biomedical applications. Due to the characteristics of the tumor microenvironment (TME), stimuli-responsive polymers that cater specifically to the TME have been extensively used to prepare smart nanovehicles for the targeted delivery of therapeutic and diagnostic agents to tumor tissues. Compared to conventional drug delivery nanosystems, TME-responsive nanosystems have many advantages, such as high sensitivity, broad applicability among different tumors, functional versatility, and improved biosafety. In recent years, a great deal of research has been devoted to engineering efficient stimuli-responsive polymeric nanosystems, and significant improvement has been made to both cancer diagnosis and therapy. In this review, we summarize some recent research advances involving the use of stimuli-responsive polymer nanocarriers in drug delivery, tumor imaging, therapy, and theranostics. Various chemical stimuli will be described in the context of stimuli-responsive nanosystems. Accordingly, the functional chemical groups responsible for the responsiveness and the strategies to incorporate these groups into the polymer will be discussed in detail. With the research on this topic expending at a fast pace, some innovative concepts, such as sequential and cascade drug release, NIR-II imaging, and multifunctional formulations, have emerged as popular strategies for enhanced performance, which will also be included here with up-to-date illustrations. We hope that this review will offer valuable insights for the selection and optimization of stimuli-responsive polymers to help accelerate their future applications in cancer diagnosis and treatment.

Conjugation Length-Dependent Raman Scattering Intensity of Conjugated Polymers

Polydiacetylenes, as a class of conjugated polymers with alternating conjugated C═C and C≡C bonds, have emerged as a promising probe material for biomedical Raman imaging, given their ultrastrong Raman scattering intensity. However, the relationship between the structure, especially the molecular length of polydiacetylenes, and their Raman scattering intensity remains unclear. In this work, a series of water-soluble polydiacetylenes, namely poly(deca-4,6-diynedioic acid) (PDDA) with different molecular weights (MWs), is prepared through controlled polymerization and degradation. The ultraviolet-visible (UV-vis) absorption spectroscopic and Raman spectroscopic studies on these polymers reveal that the Raman scattering intensity of PDDA increases nonlinearly with the MW. The MW-Raman scattering intensity relationship in the polymerization process is completely different from that in the degradation process. In contrast, the Raman scattering intensity increases more linearly with the maximal absorbance of the polymer, and the relationship between the Raman scattering intensity and the maximal absorbance of PDDA in the polymerization process is consistent with that in the degradation process. The Raman scattering intensity of PDDA hence exhibits a better dependence on the effective conjugation length of the polymer, which should guide the future design of conjugated polymers for Raman imaging applications.

A pH-responsive supramolecular hydrogel encapsulating a CuMnS nanoenzyme catalyst for synergistic photothermal-photodynamic-chemodynamic therapy of tumours

Traditional cancer therapies no longer meet the current demand for cancer precision therapy and personalized treatment and it's essential to develop new therapeutic modalities as well as to investigate new combination anti-tumor mechanisms. Therefore, amphiphilic prodrug polymer chains linking methoxy poly(ethylene glycol) (mPEG) and cinnamaldehyde (CA) with adipic acid dihydrazide (ADH) as the pH-responsive center were designed and synthesized, which could self-assemble into PAC micelles in aqueous solution. A supramolecular hydrogel was formed based on the host-guest interaction between α-cyclodextrin (α-CD) and PAC micelles. Polyetherimide (PEI) modified copper manganese sulfide nanoenzyme catalysts (PCMS NPs) were prepared by a solvothermal method, which could be uniformly dispersed in the hydrogel to form a composite supramolecular hydrogel (PCMS@PAC/α-CD Gel). Under an acidic tumor environment, pH-responsive hydrazone bonds were broken, resulting in the slow release of CA and the amplification of hydrogen peroxide (H2O2) levels. PCMS NPs exerted peroxidase (POD)-like activity and catalase (CAT)-like activity, which could convert H2O2 into hydroxyl radicals (˙OH) and oxygen (O2) to alleviate intra-tumor hypoxia and induce apoptosis, while exerting glutathione oxidase (GPX)-like activity to consume glutathione (GSH) to further enhance the effect of chemodynamic therapy (CDT). Under near-infrared light (NIR) irradiation, PCMS NPs exhibited an excellent photothermal conversion performance, which could rapidly increase the temperature of tumor cells to above 42 °C for photothermal therapy (PTT) and convert O2 to a superoxide anion (˙O2-) by exerting oxidase (OXD)-like activity for photodynamic therapy (PDT). It was demonstrated by in vitro and in vivo experiments that the PCMS@PAC/α-CD Gel was highly cytotoxic to cancer cells and could effectively inhibit tumor growth, indicating the potential for applications in the fields of biomedicine and smart materials.

Ascomylactam C Induces an Immunogenic Cell Death Signature via Mitochondria-Associated ER Stress in Lung Cancer and Melanoma

Ascomylactam C (AsC) is a new 13-membered-ring macrocyclic alkaloid, which was first isolated and identified in 2019 from the secondary metabolites of the mangrove endophytic fungus Didymella sp. CYSK-4 in the South China Sea. AsC has been found to have a broad-spectrum cytotoxic activity. However, the antitumor effects in vivo and mechanisms of AsC remain unclear. The aim of this study was to describe the effects of AsC on lung cancer and melanoma cells and to explore the antitumor molecular mechanism of AsC. In vitro, we used plate colony formation experiments and demonstrated the ability of AsC to inhibit low-density tumor growth. An Annexin V/PI cell apoptosis detection experiment revealed that AsC induced tumor cell apoptosis. In vivo, AsC suppressed the tumor growth of LLC and B16F10 allograft significantly in mice, and promoted the infiltration of CD4+ T and CD8+ T cells in tumor tissues. Mechanistically, by analyses of Western blotting, immunofluorescence and ELISA analysis, we found that AsC increased ROS formation, induced endoplasmic reticulum (ER) stress, activated the protein kinase RNA-like ER kinase (PERK)/eukaryotic translation initiation factor (eIF2α)/activating transcription factor 4 (ATF4)/C/EBP homologous protein (CHOP) signaling pathway, and induced immunogenic cell death (ICD) of tumor cells. Our results suggest that AsC may be a potentially promising antitumor drug candidate.

Mussel-inspired "plug-and-play" hydrogel glue for postoperative tumor recurrence and wound infection inhibition

Currently, clinical tumor resection is faced with two options: open and minimally invasive surgery. Open surgery is easy to completely remove the lesion but is prone to infection, while minimally invasive surgery recovers faster but may cause tumor recurrence. To fill the shortcomings of the two surgical modes and make the choice for tumor resection more effortlessly, we developed a postoperative black phosphorus-Ag nanocomposites-loaded dopamine-modified hyaluronic acid-Pluronic® F127 (BP-Ag@HA-DA-Plu) hydrogel implantation system that can prevent tumor recurrence and wound infection simultaneously. Experiments have shown that the hydrogel system combined with 808 nm near-infrared (NIR) irradiation has excellent anti-tumor, antibacterial, and wound healing abilities. Additionally, unlike existing surgical hydrogel products that require inconvenient in-situ cross-linking, the BP-Ag@HA-DA-Plu hydrogel system offers "plug-and-play" functionality during surgery due to its thermo-responsiveness, injectability, and adhesion, thereby greatly improving the efficiency of surgery.

Stimuli-responsive pressure-strain sensor-based conductive hydrogel for alleviated non-alcoholic fatty liver disease by scavenging reactive oxygen species in adipose tissue

A visible light- and reactive oxygen species (ROS)-responsive pressure/strain sensor based on carbon dot (CD)-loaded conductive hydrogel was developed for detecting high-fat diet (HFD) and preventing the risk of non-alcoholic fatty liver disease. The designed nanoparticle consisted of a diselenide polymer dot (dsPD) loaded with a visible light-responsive CD to form dsPD@CD (DSCD). The influence of visible light irradiation and ROS on DSCD facilitated the electron transport, enhancing the conductivity of DSCD-embedded hydrogel (DSCD hydrogel) from 1.3 to 35.9 mS/m. Alternatively, the tensile modulus of the DSCD hydrogel enhanced to 223 % after light-induced ROS treatment, which simultaneously impacted the capacitive response (120 %). The hydrogel implantation into inguinal white adipose tissue of HFD mice showed 82 % higher conductivity and 83 % enhanced pressure sensing response to HFD-generated high ROS levels compared with the normal diet-fed mice. Additionally, the ROS scavenging activity of DSCD hydrogel was confirmed by the downregulation of ROS-responsive genes, such as Sod2, Nrf2, and catalase (Cat) in murine primary hepatocytes isolated from fatty liver-induced mice. In addition, in vivo animal studies also confirmed the suppression of hepatic lipogenesis, as shown by decreased Pparγ and Fasn expression and hypertrophy of adipocytes in HFD mice. The distinguishable real-time wireless resistance response observed with pressure sensing indicates the potential application of the device for monitoring the risk of non-alcoholic fatty liver disease. STATEMENT OF SIGNIFICANCE: A visible-light-induced ROS-responsive carbon dot-loaded conductive hydrogel was developed for the detection of HFD-induced alterations in ROS levels by evaluating the conductivity and electrochemical responses with applied pressure/strain. The implanted hydrogel facilitates the recovery of the inflated adipocytes induced by NAFLD, which reduces fat accumulation in the liver, preventing the risk of NAFLD. Real-time detection based on the resistance response during local compression of the hydrogel is possibly performed utilizing a wireless sensing device, demonstrating the ease of NAFLD monitoring.

Exploring Thioxanthone Derivatives as Singlet Oxygen Photosensitizers for Photodynamic Therapy at the Near-IR Region

In the lowest excited triplet state, the excited photosensitizer reacts with tissue oxygen and forms reactive oxygen species (ROS), which kills tissue cells in photodynamic therapy (PDT). Metal-free thio-based pure organic molecules and analogous nucleobases can be used as photosensitizers for PDT applications. Using quantum chemical methods, we studied one- and two-photon optical absorptions, fluorescence, and other excited-state properties of substituted thioxanthone derivatives for their potential as photosensitizers for PDT. Our calculated values were compared with the available experimental data. The calculation of the intersystem crossing rate constant for these photosensitizers explains the high quantum yield of the formation of ROS, as reported experimentally. The excited triplet-state population of the photosensitizer occurs through the 1π-π* → 3n-π* channel of intersystem crossing and increases in the presence of halogen substitution.

Theranostics with photodynamic therapy for personalized medicine: to see and to treat

Photodynamic Therapy (PDT) is an approved treatment modality, which is presently receiving great attention due to its limited invasiveness, high selectivity and limited susceptibility to drug resistance. Another related research area currently expanding rapidly is the development of novel theranostic agents based on the combination of PDT with different imaging technologies, which allows for both therapy and diagnosis. This combination can help to address issues of suboptimal biodistribution and selectivity through regional imaging, while therapeutic agents enable an effective and personalized therapy. In this review, we describe compounds, whose structures combine PDT photosensitizers with different imaging probes - including examples for near-infrared optical imaging, magnetic resonance imaging (MRI) and nuclear imaging (PET or SPECT), generating novel theranostic drug candidates. We have intentionally focused our attention on novel compounds, which have already been investigated preclinically in vivo in order to demonstrate the potential of such theranostic agents for clinical applications.