A Homotypic Membrane-Camouflaged Biomimetic Nanoplatform with Gold Nanocrystals for Synergistic Photothermal/Starvation/Immunotherapy

Nanomaterials: leading immunogenic cell death-based cancer therapies

The field of oncology has transformed in recent years, with treatments shifting from traditional surgical resection and radiation therapy to more diverse and customized approaches, one of which is immunotherapy. ICD (immunogenic cell death) belongs to a class of regulatory cell death modalities that reactivate the immune response by facilitating the interaction between apoptotic cells and immune cells and releasing specific signaling molecules, and DAMPs (damage-associated molecular patterns). The inducers of ICD can elevate the expression of specific proteins to optimize the TME (tumor microenvironment). The use of nanotechnology has shown its unique potential. Nanomaterials, due to their tunability, targeting, and biocompatibility, have become powerful tools for drug delivery, immunomodulators, etc., and have shown significant efficacy in clinical trials. In particular, these nanomaterials can effectively activate the ICD, trigger a potent anti-tumor immune response, and maintain long-term tumor suppression. Different types of nanomaterials, such as biological cell membrane-modified nanoparticles, self-assembled nanostructures, metallic nanoparticles, mesoporous materials, and hydrogels, play their respective roles in ICD induction due to their unique structures and mechanisms of action. Therefore, this review will explore the latest advances in the application of these common nanomaterials in tumor ICD induction and discuss how they can provide new strategies and tools for cancer therapy. By gaining a deeper understanding of the mechanism of action of these nanomaterials, researchers can develop more precise and effective therapeutic approaches to improve the prognosis and quality of life of cancer patients. Moreover, these strategies hold the promise to overcome resistance to conventional therapies, minimize side effects, and lead to more personalized treatment regimens, ultimately benefiting cancer treatment.

Mesoporous Silica Nanoparticles as an Ideal Platform for Cancer Immunotherapy: Recent Advances and Future Directions

Cancer immunotherapy recently transforms the traditional approaches against various cancer malignancies. Immunotherapy includes systemic and local treatments to enhance immune responses against cancer and involves strategies such as immune checkpoints, cancer vaccines, immune modulatory agents, mimetic antigen-presenting cells, and adoptive cell therapy. Despite promising results, these approaches still suffer from several limitations including lack of precise delivery of immune-modulatory agents to the target cells and off-target toxicity, among others, that can be overcome using nanotechnology. Mesoporous silica nanoparticles (MSNs) are investigated to improve various aspects of cancer immunotherapy attributed to the advantageous structural features of this nanomaterial. MSNs can be engineered to alter their properties such as size, shape, porosity, surface functionality, and adjuvanticity. This review explores the immunological properties of MSNs and the use of MSNs as delivery vehicles for immune-adjuvants, vaccines, and mimetic antigen-presenting cells (APCs). The review also details the current strategies to remodel the tumor microenvironment to positively reciprocate toward the anti-tumor immune cells and the use of MSNs for immunotherapy in combination with other anti-tumor therapies including photodynamic/thermal therapies to enhance the therapeutic effect against cancer. Last, the present demands and future scenarios for the use of MSNs for cancer immunotherapy are discussed.

Advances and perspectives in phototherapy-based combination therapy for cancer treatment

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), has the advantages of spatiotemporal selectivity, non-invasiveness, and negligible drug resistance. Phototherapy has been approved for treating superficial epidermal tumors. However, its therapeutic efficacy is limited by the hypoxic tumor microenvironment and the highly expressed heat shock protein. Moreover, poor tissue penetration and focused irradiation laser region in phototherapy make treating deep tissues and metastatic tumors challenging. Combination therapy strategies, which integrate the advantages of each treatment and overcome their disadvantages, can significantly improve the therapeutic efficacy. Recently, many combination therapy strategies have been reported. Our study summarizes the strategies used for combining phototherapy with other cancer treatments such as chemotherapy, immunotherapy, sonodynamic therapy, gas therapy, starvation therapy, and chemodynamic therapy. Some research cases were selected to analyze the combination therapy effect, delivery platform feature, and synergetic anticancer mechanisms. Moreover, additional research cases are summarized in the tables. This review provides strong evidence that phototherapy-based combination strategies can enhance the anticancer effect compared with phototherapy alone. Additionally, the challenges and future perspectives associated with these combinational therapies are discussed.

Cell membrane coated nanoparticles as a biomimetic drug delivery platform for enhancing cancer immunotherapy

Cancer immunotherapy, a burgeoning modality for cancer treatment, operates by activating the autoimmune system to impede the growth of malignant cells. Although numerous immunotherapy strategies have been employed in clinical cancer therapy, the resistance of cancer cells to immunotherapeutic medications and other apprehensions impede the attainment of sustained advantages for most patients. Recent advancements in nanotechnology for drug delivery hold promise in augmenting the efficacy of immunotherapy. However, the efficacy is currently constrained by the inadequate specificity of delivery, low rate of response, and the intricate immunosuppressive tumor microenvironment. In this context, the investigation of cell membrane coated nanoparticles (CMNPs) has revealed their ability to perform targeted delivery, immune evasion, controlled release, and immunomodulation. By combining the advantageous features of natural cell membranes and nanoparticles, CMNPs have demonstrated their unique potential in the realm of cancer immunotherapy. This review aims to emphasize recent research progress and elucidate the underlying mechanisms of CMNPs as an innovative drug delivery platform for enhancing cancer immunotherapy. Additionally, it provides a comprehensive overview of the current immunotherapeutic strategies involving different cell membrane types of CMNPs, with the intention of further exploration and optimization.

Cell membrane-based biomimetic technology for cancer phototherapy: Mechanisms, recent advances and perspectives

Despite significant advances in medical technology and antitumour treatments, the diagnosis and treatment of tumours have undergone remarkable transformations. Noninvasive phototherapy methods, such as photodynamic therapy (PDT) and photothermal therapy (PTT), have gained significant interest in antitumour medicine. However, traditional photosensitisers or photothermal agents face challenges like immune system recognition, rapid clearance from the bloodstream, limited tumour accumulation, and phototoxicity concerns. Researchers combine photosensitisers or photothermal agents with natural cell membranes to overcome these obstacles to create a nano biomimetic therapeutic platform. When used to coat nanoparticles, red blood cells, platelets, cancer cells, macrophages, lymphocytes, and bacterial outer membranes could provide prolonged circulation, tumour targeting, immune stimulation, or antigenicity. This article covers the principles of cellular membrane biomimetic nanotechnology and phototherapy, along with recent advancements in applying nano biomimetic technology to PDT, PTT, PCT, and combined diagnosis and treatment. Furthermore, the challenges and issues of using nano biomimetic nanoparticles in phototherapy are discussed. STATEMENT OF SIGNIFICANCE: Currently, there has been significant progress in the field of cell membrane biomimetic technology. Researchers are exploring its potential application in tumor diagnosis and treatment through phototherapy. Scholars have conducted extensive research on combining cell membrane technology and phototherapy in anticancer diagnosis and treatment. This review aims to highlight the mechanisms of phototherapy and the latest advancements in single phototherapy (PTT, PDT) and combination phototherapy (PCT, PRT, and PIT), as well as diagnostic approaches. The review provides an overview of various cell membrane technologies, including RBC membranes, platelet membranes, macrophage cell membranes, tumour cell membranes, bacterial membranes, hybrid membranes, and their potential for anticancer applications under phototherapy. Lastly, the review discusses the challenges and future directions in this field.

Photothermal Effect of Gold Nanoparticles as a Nanomedicine for Diagnosis and Therapeutics

Gold nanoparticles (AuNPs) have received great attention for various medical applications due to their unique physicochemical properties. AuNPs with tunable optical properties in the visible and near-infrared regions have been utilized in a variety of applications such as in vitro diagnostics, in vivo imaging, and therapeutics. Among the applications, this review will pay more attention to recent developments in diagnostic and therapeutic applications based on the photothermal (PT) effect of AuNPs. In particular, the PT effect of AuNPs has played an important role in medical applications utilizing light, such as photoacoustic imaging, photon polymerase chain reaction (PCR), and hyperthermia therapy. First, we discuss the fundamentals of the optical properties in detail to understand the background of the PT effect of AuNPs. For diagnostic applications, the ability of AuNPs to efficiently convert absorbed light energy into heat to generate enhanced acoustic waves can lead to significant enhancements in photoacoustic signal intensity. Integration of the PT effect of AuNPs with PCR may open new opportunities for technological innovation called photonic PCR, where light is used to enable fast and accurate temperature cycling for DNA amplification. Additionally, beyond the existing thermotherapy of AuNPs, the PT effect of AuNPs can be further applied to cancer immunotherapy. Controlled PT damage to cancer cells triggers an immune response, which is useful for obtaining better outcomes in combination with immune checkpoint inhibitors or vaccines. Therefore, this review examines applications to nanomedicine based on the PT effect among the unique optical properties of AuNPs, understands the basic principles, the advantages and disadvantages of each technology, and understands the importance of a multidisciplinary approach. Based on this, it is expected that it will help understand the current status and development direction of new nanoparticle-based disease diagnosis methods and treatment methods, and we hope that it will inspire the development of new innovative technologies.

Research progress of nanovaccine in anti-tumor immunotherapy

Tumor vaccines aim to activate dormant or unresponsive tumor-specific T lymphocytes by using tumor-specific or tumor-associated antigens, thus enhancing the body's natural defense against cancer. However, the effectiveness of tumor vaccines is limited by the presence of tumor heterogeneity, low immunogenicity, and immune evasion mechanisms. Fortunately, multifunctional nanoparticles offer a unique chance to address these issues. With the advantages of their small size, high stability, efficient drug delivery, and controlled surface chemistry, nanomaterials can precisely target tumor sites, improve the delivery of tumor antigens and immune adjuvants, reshape the immunosuppressive tumor microenvironment, and enhance the body's anti-tumor immune response, resulting in improved efficacy and reduced side effects. Nanovaccine, a type of vaccine that uses nanotechnology to deliver antigens and adjuvants to immune cells, has emerged as a promising strategy for cancer immunotherapy due to its ability to stimulate immune responses and induce tumor-specific immunity. In this review, we discussed the compositions and types of nanovaccine, and the mechanisms behind their anti-tumor effects based on the latest research. We hope that this will provide a more scientific basis for designing tumor vaccines and enhancing the effectiveness of tumor immunotherapy.

Recent advances of nanocrystals in cancer theranostics

Emerging cancer cases across the globe and treating them with conventional therapies with multiple limitations have been challenging for decades. Novel drug delivery systems and alternative theranostics are required for efficient detection and treatment. Nanocrystals (NCs) have been established as a significant cancer diagnosis and therapeutic tool due to their ability to deliver poorly water-soluble drugs with sustained release, low toxicity, and flexibility in the route of administration, long-term sustainable drug release, and noncomplicated excretion. This review summarizes several therapies of NCs, including anticancer, immunotherapy, radiotherapy, biotheranostics, targeted therapy, photothermal, and photodynamic. Further, different imaging and diagnostics using NCs are mentioned, including imaging, diagnosis through magnetic resonance imaging (MRI), computed tomography (CT), biosensing, and luminescence. In addition, the limitations and potential solutions of NCs in the field of cancer theranostics are discussed. Preclinical and clinical data depicting the importance of NCs in the spotlight of cancer, its current status, future aspects, and challenges are covered in detail.

Nanoparticle-based drug delivery systems to enhance cancer immunotherapy in solid tumors

Immunotherapy has developed rapidly in solid tumors, especially in the areas of blocking inhibitory immune checkpoints and adoptive T-cell transfer for immune regulation. Many patients benefit from immunotherapy. However, the response rate of immunotherapy in the overall population are relatively low, which depends on the characteristics of the tumor and individualized patient differences. Moreover, the occurrence of drug resistance and adverse reactions largely limit the development of immunotherapy. Recently, the emergence of nanodrug delivery systems (NDDS) seems to improve the efficacy of immunotherapy by encapsulating drug carriers in nanoparticles to precisely reach the tumor site with high stability and biocompatibility, prolonging the drug cycle of action and greatly reducing the occurrence of toxic side effects. In this paper, we mainly review the advantages of NDDS and the mechanisms that enhance conventional immunotherapy in solid tumors, and summarize the recent advances in NDDS-based therapeutic strategies, which will provide valuable ideas for the development of novel tumor immunotherapy regimen.

Biomimetic Cell-Derived Nanoparticles: Emerging Platforms for Cancer Immunotherapy

Cancer immunotherapy can significantly prevent tumor growth and metastasis by activating the autoimmune system without destroying normal cells. Although cancer immunotherapy has made some achievements in clinical cancer treatment, it is still restricted by systemic immunotoxicity, immune cell dysfunction, cancer heterogeneity, and the immunosuppressive tumor microenvironment (ITME). Biomimetic cell-derived nanoparticles are attracting considerable interest due to their better biocompatibility and lower immunogenicity. Moreover, biomimetic cell-derived nanoparticles can achieve different preferred biological effects due to their inherent abundant source cell-relevant functions. This review summarizes the latest developments in biomimetic cell-derived nanoparticles for cancer immunotherapy, discusses the applications of each biomimetic system in cancer immunotherapy, and analyzes the challenges for clinical transformation.

Mesoporous silica/organosilica nanoparticles for cancer immunotherapy

Cancer is one of the fatal diseases in the history of humankind. In this regard, cancer immunotherapeutic strategies have revolutionized the traditional mode of cancer treatment. Silica based nano-platforms have been extensively applied in nanomedicine including cancer immunotherapy. Mesoporous silica nanoparticles (MSN) and mesoporous organosilica nanoparticles (MON) are attractive candidates due to the ease in controlling the structural parameters as needed for the targeted immunotherapeutic applications. Especially, the MON provide an additional advantage of controlling the composition and modulating the biological functions to actively synergize with other immunotherapeutic strategies. In this review, the applications of MSN, MON, and metal-doped MSN/MON in the field of cancer immunotherapy and tumor microenvironment regulation are comprehensively summarized by highlighting the structural and compositional attributes of the silica-based nanoplatforms.

Recent advances in nanoscale metal-organic frameworks for cancer chemodynamic therapy

Chemodynamic therapy (CDT), a novel therapeutic approach based on Fenton (Fenton-like) reaction, has been widely employed for tumor therapy. This approach utilizes Fe, Cu, or other metal ions (Mn, Zn, Co, or Mo) to react with the excess hydrogen peroxide (H₂O₂) in tumor microenvironments (TME), and form highly cytotoxic hydroxyl radical (˙OH) to kill cancer cells. Recently, nanoscale metal-organic frameworks (nMOFs) have attracted considerable attention as promising CDT agents with the rapid development of cancer CDT. This review focuses on summarizing the latest advances (2020-2022) on the design of nMOFs as nanomedicine for CDT or combination therapy of CDT and other therapies. The future development and challenges of CDT are also proposed based on recent progress. Our group hopes that this review will enlighten the research and development of nMOFs for CDT.

Biomimetic Active Materials Guided Immunogenic Cell Death for Enhanced Cancer Immunotherapy

Despite immunotherapy emerging as a vital approach to improve cancer treatment, the activation of efficient immune responses is still hampered by immunosuppression, especially due to the low tumor immunogenicity. Immunogenic cell death (ICD) is a promising strategy to reshape the tumor microenvironment (TME) for achieving high immunogenicity. Various stimuli are able to effectively initiate their specific ICD by utilizing the corresponding ICD-inducer. However, the ICD-guided antitumor immune effects are usually impaired by various biological barriers and TME-associated immune resistance. Biomimetic active materials are being extensively explored as guided agents for ICD due to their unique advantages. In this review, two major strategies are systematically introduced that have been employed to exploit biomimetic active materials guided ICD for cancer immunotherapy, mainly including naive organism-derived nanoagents and engineered bioactive platforms. This review outlines the recent advances in the field at biomimetic active materials guided physiotherapy, chemotherapy, and biotherapy for ICD induction. The advances and challenges of biomimetic active materials guided ICD for cancer immunotherapy applications are further discussed in future clinical practice. This review provides an overview of the advances of biomimetic active materials for targeting immunoregulation and treatment and can contribute to the future of advanced antitumor combination therapy.

Cascade reaction triggering and photothermal AuNPs@MIL MOFs doped intraocular lens for enhanced posterior capsular opacification prevention

Posterior capsular opacification (PCO) is the most common complication after cataract surgery. Present strategies can't meet the clinical needs of long-term prevention. This research reports a novel intraocular lens (IOL) bulk material with high biocompatibility and synergistic therapy. Gold nanoparticles (AuNPs) doped MIL-101-NH₂ metal-organic frameworks (MOFs) (AuNPs@MIL) was firstly fabricated via in situ reductions. Then the functionalized MOFs were uniformly mixed with glycidyl methacrylate (GMA) and 2-(2-ethoxyethoxy) ethyl acrylate (EA) to form the nanoparticle doped polymer (AuNPs@MIL-PGE), and which was used to fabricate IOL bulk materials. The materials' optical and mechanical properties with different mass contents of nanoparticles are investigated. Such bulk functionalized IOL material could efficiently remove residual human lens epithelial cells (HLECs) in the capsular bag in the short term, and can prevent PCO on demand in the long run by near-infrared illumination (NIR) action. In vivo and in vitro experiments demonstrate the biosafety of the material. The AuNPs@MIL-PGE exhibits excellent photothermal effects, which could inhibit cell proliferation under NIR and doesn't cause pathological effects on the surrounding tissues. Such functionalized IOL can not only avoid the side effects of the antiproliferative drugs but also realize the enhanced PCO prevention in clinical practice.

Rhythm Mild-Temperature Photothermal Therapy Enhancing Immunogenic Cell Death Response in Oral Squamous Cell Carcinoma

The low antitumor efficiency and unexpected thermo-tolerance activation of mild-temperature photothermal therapy (mPTT) severely impede the therapeutic efficacy, thereby the implementation of reasonable mPTT procedure to improve antitumor efficiency is of great significance for clinical transformation. Herein, a rhythm mPTT with organic photothermal nanoparticles (PBDB-T NPs) is demonstrated, synergistically increasing tumor elimination and intense immunogenic cancer cell death (ICD) to elicit tumor-specific immune responses for tumor treatment. Specifically, PBDB-T NPs are characterized by favorable biocompatibility, excellent and controllable photothermal properties, exhibit the properties of noninvasive diagnostic imaging, and effective mPTT against oral squamous cell carcinoma (OSCC). Encouragingly, a temperature-dependent release of damage-associated molecular patterns (DAMPs) is discovered during the mPTT-induced ICD. Meanwhile, orchestrated rhythm mPTT referring to radiotherapy procedure amplifies and balances antitumor efficiency and abundant DAMPs generation to gain optimal immune activation within clinical-recommended hyperthermia temperature compared with conventional PTT. The in vitro and in vivo results show that the rhythm mPTT unites the killing effect and ICD induction, generating strong mPTT efficacy and active tumor-specific adaptive immune responses. The study offers a promising strategy and a new opportunity for the clinical application of mPTT.

A Catalytic Immune Activator Based on Magnetic Nanoparticles to Reprogram the Immunoecology of Breast Cancer from "Cold" to "Hot" State

Triple-negative breast cancer (TNBC) as "cold" tumor is characterized by severe immunosuppression of the tumor microenvironment (TME). To effectively activate the immune response of TNBC, a new kind of therapy strategy called cancer catalytic immunotherapy is proposed based on magnetic nanoparticles (NPs) as immune activators. Utilizing the weak acidity and excessive hydrogen peroxide of TME, these magnetic NPs can release ferrous ions to promote Fenton reaction, leading to abundant ·OH and reactive oxygen species (ROS) for ultimately killing cancer cells. Mechanistically, these magnetic NPs activate the ROS-related signaling pathway to generate more ROS. Meanwhile, these magnetic NPs with unique immunological properties can promote the maturation of dendritic cells and the polarization of macrophages from M2 to M1, resulting in the infiltration of more T cells to reprogram the immunoecology of TNBC from "cold" to "hot" state. Besides directly affecting immune cells, these magnetic NPs can also affect the secretion of some immune-related cytokines by cancer cells, to further indirectly activate the immune response. In conclusion, these catalytic immune activators are designed to achieve the synergistic treatment of chemodynamic therapy-enhanced immunotherapy guided by computed tomography (CT)/near-infrared region-II (NIR-II) dual-mode imaging, providing a new strategy for TNBC treatment.

Membrane-wrapped nanoparticles for photothermal cancer therapy

Cancer is a global health problem that needs effective treatment strategies. Conventional treatments for solid-tumor cancers are unsatisfactory because they cause unintended harm to healthy tissues and are susceptible to cancer cell resistance. Nanoparticle-mediated photothermal therapy is a minimally invasive treatment for solid-tumor cancers that has immense promise as a standalone therapy or adjuvant to other treatments like chemotherapy, immunotherapy, or radiotherapy. To maximize the success of photothermal therapy, light-responsive nanoparticles can be camouflaged with cell membranes to endow them with unique biointerfacing capabilities that reduce opsonization, prolong systemic circulation, and improve tumor delivery through enhanced passive accumulation or homotypic targeting. This ensures a sufficient dose of photoresponsive nanoparticles arrives at tumor sites to enable their complete thermal ablation. This review summarizes the state-of-the-art in cell membrane camouflaged nanoparticles for photothermal cancer therapy and provides insights to the path forward for clinical translation.

Naphthofluorescein-based organic nanoparticles with superior stability for near-infrared photothermal therapy

Photothermal agents (PTAs) based on organic small molecules with near-infrared (NIR) absorption (700-900 nm) have attracted increasing attention in cancer photothermal therapy (PTT). However, NIR organic PTAs often suffer from poor stability. Fluorescein and its derivatives have been widely used in biological imaging and sensing due to their minimal cytotoxicity. But fluorescein and its derivatives have not been used in PTT because most of them don't have NIR absorption. In this work, two NIR naphthofluorescein derivatives, namely NFOM-1 and NFOM-2, were synthesized. In contrast to NFOM-1, NFOM-2 possesses an intramolecular hydrogen bonding network, which extends the absorption to the NIR region and significantly improves the photostability. NFOM-2 was encapsulated into an amphiphilic polymer (DSPE-mPEG2000) to obtain NFOMNPs as PTAs. Compared to the organic molecule NFOM-2, the absorption of NFOMNPs is broadened and further red-shifted to fit an 808 nm light source. Moreover, NFOMNPs exhibit good photothermal conversion efficiency (PCE, 40.4%, 808 nm, 1.0 W cm^-2), remarkable photostability and physiological stability, and significant PTT efficacy in vitro and in vivo was achieved. In other words, this study provides an intramolecular hydrogen bond network strategy and a fluorescein-based molecular platform to construct ultra-stable PTAs for efficient NIR PTT.

Glucose Metabolism Intervention-Facilitated Nanomedicine Therapy

Ordinarily, cancer cells possess features of abnormally increased nutrient intake and metabolic pathways. The disorder of glucose metabolism is the most important among them. Therefore, starvation therapy targeting glucose metabolism specifically, which results in metabolic disorders, restricted synthesis, and inhibition of tumor growth, has been developed for cancer therapy. However, issues such as inadequate targeting effectiveness and drug tolerance impede their clinical transformation. In recent years, nanomaterial-assisted starvation treatment has made significant progress in addressing these challenges, whether as a monotherapy or in combination with other medications. Herein, representative researches on the construction of nanosystems conducting starvation therapy are introduced. Elaborate designs and interactions between different treatment mechanisms are meticulously mentioned. Not only are traditional treatments based on glucose oxidase involved, but also newly sprung small molecule agents targeting glucose metabolism. The obstacles and potential for advancing these anticancer therapies were also highlighted in this review.

Multifunctional Role of Silica in Pharmaceutical Formulations

Due to the high surface area, adjustable surface and pore structures, and excellent biocompatibility, nano- and micro-sized silica have certainly attracted the attention of many researchers in the medical fields. This review focuses on the multifunctional roles of silica in different pharmaceutical formulations including solid preparations, liquid drugs, and advanced drug delivery systems. For traditional solid preparations, it can improve compactibility and flowability, promote disintegration, adjust hygroscopicity, and prevent excessive adhesion. As for liquid drugs and preparations, like volatile oil, ethers, vitamins, and self-emulsifying drug delivery systems, silica with adjustable pore structures is a good adsorbent for solidification. Also, silica with various particle sizes, surface characteristics, pore structure, and surface modification controlled by different synthesis methods has gained wide attention owing to its unparalleled advantages for drug delivery and disease diagnosis. We also collate the latest pharmaceutical applications of silica sorted out by formulations. Finally, we point out the thorny issues for application and survey future trends pertaining to silica in an effort to provide a comprehensive overview of its future development in the medical fields. Graphical Abstract.

Tumor microenvironment responsive self-cascade catalysis for synergistic chemo/chemodynamic therapy by multifunctional biomimetic nanozymes

Chemodynamic therapy (CDT) is an emerging approach to treat cancer based on the tumor microenvironment (TME), but its limited content of endogenous hydrogen peroxide (H₂O₂) weakens the anticancer effects. Herein, a multifunctional biomimetic nanozyme (Se@SiO₂-Mn@Au/DOX, named as SSMA/DOX) is fabricated, which undergoes TME responsive self-cascade catalysis to facilitate MRI guided enhanced chemo/chemodynamic therapy. The SSMA/DOX nanocomposites (NCs) responsively degrade in acidic conditions of tumor to release Se, DOX, Au and Mn²⁺. Mn²⁺ not only enables MRI to guided therapy, but also catalyzes the endogenous H₂O₂ into hydroxyl radical (˙OH) for CDT. In addition, the Au NPs continuously catalyze glucose to generate H₂O₂, enhancing CDT by supplementing a sufficiently reactive material and cutting off the energy supply of the tumor by consuming glucose. Simultaneously, Se enhances the chemotherapy of doxorubicin hydrochloride (DOX) and CDT by upregulating ROS in the tumor cells, achieving remarkable inhibition effect towards tumor. Moreover, SSMA/DOX NCs have good biocompatibility and degradability, which avoid long-term toxicity and side effects. Overall, the degradable SSMA/DOX NCs provide an innovative strategy for tumor microenvironment responsive self-cascade catalysis to enhance tumor therapy.

Self-adjuvanting photosensitizer nanoparticles for combination photodynamic immunotherapy

Combination cancer immunotherapy that synergizes the advantages of multiple therapeutic agents has shown great potential in tumor treatment. Herein, we report the one-step assembly of therapeutic nanoparticles (NPs) to co-deliver photosensitizers and adjuvants for combination photodynamic therapy (PDT) and immunotherapy. The NPs are obtained via self-assembly of chlorin e6 (Ce6) and imidazoquinoline-based TLR7 agonists (IMDQ), which results in a high loading efficacy of 72.2% and 27.8% for Ce6 and IMDQ, respectively. Upon laser irradiation, the resulting NPs could not only effectively induce photodynamic immunogenic cancer cell death, but also elicit robust antitumor immunity, leading to significant inhibition of both primary and distant tumors in a bilateral tumor model. This study demonstrates the potential of self-assembled NPs in co-delivering multiple therapeutics for potential immunotherapy to enhance the antitumor efficacy.