Multifunctional Nano-Biomaterials for Cancer Therapy via Inducing Enhanced Immunogenic Cell Death

Enhancing Ferroptosis-Mediated Radiosensitization via Synergistic Disulfidptosis Induction

Ferroptosis plays an important role in radiotherapy (RT), and the induction of ferroptosis can effectively sensitize radiotherapy. However, the therapeutic efficiency is always affected by ferroptosis resistance, especially SLC7A11 (Solute Carrier Family 7 Member 11)-cystine-cysteine-GSH (glutathione)-GPX4 (glutathione peroxidase 4) pathway-mediated resistance. In this study, tumor-microenvironment self-activated high-Z element-containing nanoferroptosis inducers, PEGylated Fe-Bi-SS metal-organic frameworks (FBSP MOFs), were developed to sensitize RT. Unexpectedly, ferroptosis-resistant SLC7A11 would be self-adaptively upregulated, leading to self-responsive ferroptosis resistance. Since the conversion from SLC7A11-transported cystine to cysteine is highly glucose-dependent, glucose oxidase (GOx) was incorporated in the MOFs, causing the depletion of NADPH (nicotinamide adenine dinucleotide phosphate) to terminate the conversion from cystine to cysteine, relieving the self-adaptive ferroptosis resistance. Excitingly, the accumulation of cystine would synergistically lead to disulfide stress and trigger disulfidptosis, making a new contribution to enhance therapeutic efficiency. Moreover, the hydrogen peroxide produced during glucose oxidation could also cascade-react with the Fenton reaction, therefore enhancing ferropotosis. Both in vitro and in vivo results suggested that therapeutic efficiency of ferroptosis-mediated radiosensitization could be enhanced benefiting from synergistic disulfidptosis induction, indicating that disulfidptosis might be an efficient strategy to relieve ferroptosis resistance and enhance RT efficiency.

Emerging nitric oxide gas-assisted cancer photothermal treatment

Photothermal therapy (PTT) has garnered significant attention in recent years, but the standalone application of PTT still faces limitations that hinder its ability to achieve optimal therapeutic outcomes. Nitric oxide (NO), being one of the most extensively studied gaseous molecules, presents itself as a promising complementary candidate for PTT. In response, various nanosystems have been developed to enable the simultaneous utilization of PTT and NO-mediated gas therapy (GT), with the integration of photothermal agents (PTAs) and thermally-sensitive NO donors being the prevailing approach. This combination seeks to leverage the synergistic effects of PTT and GT while mitigating the potential risks associated with gas toxicity through the use of a single laser irradiation. Furthermore, additional internal or external stimuli have been employed to trigger NO release when combined with different types of PTAs, thereby further enhancing therapeutic efficacy. This comprehensive review aims to summarize recent advancements in NO gas-assisted cancer photothermal treatment. It commences by providing an overview of various types of NO donors and precursors, including those sensitive to photothermal, light, ultrasound, reactive oxygen species, and glutathione. These NO donors and precursors are discussed in the context of dual-modal PTT/GT. Subsequently, the incorporation of other treatment modalities such as chemotherapy (CHT), photodynamic therapy (PDT), alkyl radical therapy, radiation therapy, and immunotherapy (IT) in the creation of triple-modal therapeutic nanoplatforms is presented. The review further explores tetra-modal therapies, such as PTT/GT/CHT/PDT, PTT/GT/CHT/chemodynamic therapy (CDT), PTT/GT/PDT/IT, PTT/GT/starvation therapy (ST)/IT, PTT/GT/Ca2+ overload/IT, PTT/GT/ferroptosis (FT)/IT, and PTT/GT/CDT/IT. Finally, potential challenges and future perspectives concerning these novel paradigms are discussed. This comprehensive review is anticipated to serve as a valuable resource for future studies focused on the development of innovative photothermal/NO-based cancer nanotheranostics.

Triggering immunogenic death of cancer cells by nanoparticles overcomes immunotherapy resistance

Immunotherapy resistance poses a significant challenge in oncology, necessitating novel strategies to enhance the therapeutic efficacy. Immunogenic cell death (ICD), including necroptosis, pyroptosis and ferroptosis, triggers the release of tumor-associated antigens and numerous bioactive molecules. This release can potentiate a host immune response, thereby overcoming resistance to immunotherapy. Nanoparticles (NPs) with their biocompatible and immunomodulatory properties, are emerging as promising vehicles for the delivery of ICD-inducing agents and immune-stimulatory adjuvants to enhance immune cells tumoral infiltration and augment immunotherapy efficacy. This review explores the mechanisms underlying immunotherapy resistance, and offers an in-depth examination of ICD, including its principles and diverse modalities of cell death that contribute to it. We also provide a thorough overview of how NPs are being utilized to trigger ICD and bolster antitumor immunity. Lastly, we highlight the potential of NPs in combination with immunotherapy to revolutionize cancer treatment.

Biodegradable persistent ROS-generating nanosonosensitizers for enhanced synergistic cancer therapy by inducing cascaded oxidative stress

Sonodynamic therapy (SDT) is gaining popularity in cancer treatment due to its superior controllability and high tissue permeability. Nonetheless, the efficacy of SDT is severely diminished by the transient generation of limited reactive oxygen species (ROS). Herein, we introduce an acid-activated nanosonosensitizer, CaO2@PCN, by the controllable coating of porphyrinic metal-organic frameworks (PCN-224) on CaO2 to induce cascaded oxidative stress in tumors. The PCN-224 doping can generate ROS during SDT to induce intracellular oxidative stress and abnormal calcium channels. Meanwhile, the ultrasound also promotes extracellular calcium influx. In addition, CaO2@PCN sequentially degrades in the tumor cell lysosomes, releasing Ca2+ and H2O2 to induce further abnormal calcium channels and elevate the levels of Ca2+. Insufficient catalase (CAT) in tumor cells promotes intracellular calcium overload, which can induce persistent ROS generation and mitochondrial dysfunction through ion interference therapy (IIT). More importantly, PCN-224 also protects CaO2 against significant degradation under neutral conditions. Hence, the well-designed CaO2@PCN produces synergistic SDT/IIT effects and persistent ROS against cancer. More notably, the acidity-responsive biodegradability endows CaO2@PCN with excellent biosafety and promising clinical potential.

Advancements in nano-immunotherapy for gynecological cancers: A new frontier

Gynecological cancers rank among the leading causes of death for women worldwide. Traditional treatment methods, including surgery, chemotherapy, and radiotherapy, are commonly employed in patients with these tumors. However, the effectiveness of these approaches remains suboptimal due to issues like treatment resistance and challenges in early detection. As an alternative, immunotherapy has shown promise by offering improved anti-tumor responses and fewer side effects. In recent years, there have been significant advances in nanoparticle (NP) and nanoengineering technologies, paving the way for the development of nano-immunotherapy-an approach designed to enhance the effectiveness of immunotherapy. Thanks to the flexibility, adaptability, small size, and responsiveness of NP platforms to the tumor microenvironment (TME), nano-immunotherapy has demonstrated improved anti-tumor activity and safety. This is achieved through enhanced tumor targeting, better delivery of immune agents, and reduced toxicity and side effects. Recently, researchers have explored the application of nano-immunotherapy in treating gynecological cancers, aiming to slow tumor progression and improve patient outcomes. In this review, we provide an overview of the latest advances in nano-immunotherapy for gynecological cancers, including ovarian, cervical, and endometrial cancers. Additionally, we discuss the challenges facing the clinical translation of nano-immunotherapy from the lab to real-world applications.

Mitochondria-Targeted Icaritin Nanoparticles Induce Immunogenic Cell Death in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly malignant tumor that is resistant to chemotherapy and immunotherapy. Icaritin (ICT), a traditional Chinese medicine, has been reported as an immunoregulatory agent for treating advanced unresectable HCC. ICT induces mitophagy to cause immunogenic cell death (ICD); however, the poor bioavailability of ICT limits its therapeutic efficacy and clinical use. Therefore, this study aimed to assess the effect of using the poly(2-(N-oxide-N,N-diethylamino) ethyl methacrylate)-b-poly(ε-caprolactone) copolymer (OPDEA-PCL) to encapsulate ICT into nanoparticles (ICT NPs). OPDEA-PCL/ICT NPs colocalized with the mitochondria, promoting the ICD induction effect of ICT in mouse HCC H22 cells. In the H22 subcutaneous tumor model, intravenously injected OPDEA-PCL/ICT NPs quickly accumulated in the tumor and efficiently activated systemic anticancer immunogenicity through their effects on mitophagy. The resulting tumor suppression rate was 60%, which was significantly higher than that of free ICT and poly(ethylene glycol) (PEG)-PCL/ICT NPs. Furthermore, mouse survival was also prolonged by nearly 2-fold with OPDEA-PCL/ICT NPs compared with PBS. In summary, this approach provides valuable insights into improving the immunotherapeutic efficacy of ICT for HCC.

Thiophene assisted cellular uptake enhancement for highly efficient NIR-II cancer phototheranostics

We designed two series of NIR-II PTAs with D-A or D-A-D structures, in which the introduction of thiophene promotes a bathochromic shift of emission into the NIR-II region, helps to improve the cellular uptake of the PTAs and facilitates NIR-II imaging-guided PDT/PTT cancer phototherapy.

Nanomedicine for combination of chemodynamic therapy and immunotherapy of cancers

Chemodynamic therapy (CDT), as a new type of therapy, has received more and more attention in the field of tumor therapy in recent years. By virtue of the characteristics of weak acidity and excess H2O2 in the tumor microenvironment, CDT uses the Fenton or Fenton-like reactions to catalyze the transformation of H2O2 into strongly oxidizing ˙OH, resulting in increased intracellular oxidative stress for lipid oxidation, protein inactivation, or DNA damage, and finally inducing apoptosis of cancer cells. In particular, CDT has the advantage of tumor specificity. However, the therapeutic efficacy of CDT frequently depends on the catalytic efficiency of the Fenton reaction, which needs the presence of sufficient H2O2 and catalytic metal ions. Relatively low concentrations of H2O2 and the lack of catalytic metal ions usually limit the final therapeutic effect. The combination of CDT with immunotherapy will be an effective means to improve the therapeutic effect. In this review paper, the recent progress related to nanomedicine for the combination of CDT and immunotherapy is summarized. Immunogenic death of tumor cells, immune checkpoint inhibitors, and stimulator of interferon gene (STING) activation as the main immunotherapy strategies to combine with CDT are discussed. Finally, the challenges and prospects for the clinical translation and future development direction are discussed.

Inhalable nanoparticles with enhanced cuproptosis and cGAS-STING activation for synergistic lung metastasis immunotherapy

Due to the insufficient Cu+ accumulation, Cu+ efflux mechanism, and highly immunosuppressive tumor microenvironment (TME) in lung metastasis, the cuproptosis efficacy is limited. Herein, an inhalable nanodevice (CLDCu) is constructed to successfully overcome the drawbacks of cuproptosis. CLDCu consists of a Cu2+-chitosan shell and low molecular weight heparin-tocopherol succinate (LMWH-TOS, LT) core with disulfiram (DSF) loading. The prepared CLDCu can be inhaled and accumulate in large amounts in lung lesions (63.6%) with 56.5 times higher than intravenous injection. Within tumor cells, the mild acidity triggers the co-release of DSF and Cu2+, thus generating bis(diethyldithiocarbamate)-copper (CuET) to block Cu+ efflux protein ATP7B and forming toxic Cu+, leading to enhanced cuproptosis. Meanwhile, the released chitosan cooperates with CLDCu-induced cuproptosis to activate stimulator of interferon genes (STING) pathway, which significantly potentiates dendritic cells (DCs) maturation, as wells as evokes innate and adaptive immunity. In lung metastatic mice model, CLDCu is found to induce cuproptosis and reverse the immunosuppressive TME by inhalation administration. Moreover, CLDCu combined with anti-programmed cell death protein ligand-1 antibody (aPD-L1) provokes stronger antitumor immunity. Therefore, nanomedicine that combines cuproptosis with STING activation is a novel strategy for tumor immunotherapy.

Advances in antitumor application of ROS enzyme-mimetic catalysts

The rapid growth of research on enzyme-mimetic catalysts (Enz-Cats) is expected to promote further advances in nanomedicine for biological detection, diagnosis and treatment of disease, especially tumors. ROS-based nanomedicines present fascinating potential in antitumor therapy owing to the rapid development of nanotechnology. In this review, we focus on the applications of Enz-Cats based on ROS in antitumor therapy. Firstly, the definition and category of ROS are introduced, and the key factors enhancing ROS levels are carefully elucidated. Then, the rationally engineered Enz-Cats via different synthetic approaches with high ROS-producing efficiencies are comprehensively discussed. Subsequently, oncotherapy application of Enz-Cats is comprehensively discussed, which integrates diverse synergistic treatment modalities and exhibits high efficiency in ROS generation. Finally, the challenges and future research direction of this field are presented. This review is dedicated to unraveling the enigmas surrounding the interplay of nanomedicine and organisms.

Accurately Controlled Tumor Temperature with Silica-Coated Gold Nanorods for Optimal Immune Checkpoint Blockade Therapy

Photothermal therapy (PTT) at mild temperatures ranging from 44 to 45 °C holds tremendous promise as a strategy for inducing potent immunogenic cell death (ICD) within tumor tissues, which can reverse the immunosuppressive tumor microenvironment (ITM) into an immune-responsive milieu. However, accurately and precisely controlling the tumor temperature remains a formidable challenge. Here, we report the precision photothermal immunotherapy by using silica-coated gold nanorods (AuNR@SiO2), and investigating the optimal administration routes and treatment protocols, which enabled to achieve the sustained and controlled mild heating within the tumor tissues. First, the highest photothermal performance of AuNR@SiO2 with 20-nm silica shell thickness than 5 or 40 nm was confirmed in vitro and in vivo. Then, the optimal conditions for precision immunotherapy were further investigated to produce mild temperature (44 to 45 °C) accurately in tumor tissues. The optimal conditions with AuNR@SiO2 result in a distinct cell death with high early/late apoptosis and low necrosis, leading to very efficient ICD compared to lower or higher temperatures. In colon tumor-bearing mice, intratumorally injected AuNR@SiO2 efficiently promotes a mild temperature within the tumor tissues by local irradiation of near-infrared (NIR) laser. This mild PTT substantially increases the population of mature dendritic cells (DCs) and cytotoxic T cells (CTLs) within tumor tissues, ultimately reversing the ITM into an immune-responsive milieu. Furthermore, we found that the combination mild PTT with AuNR@SiO2 and anti-PD-L1 therapy could lead to the 100% complete regression of primary tumors and immunological memory to prevent tumor recurrence. Collectively, this study demonstrates that AuNR@SiO2 with a robust methodology capable of continuously inducing mild temperature accurately within the ITM holds promise as an approach to achieve the precision photothermal immunotherapy.

Advancing nanotechnology for neoantigen-based cancer theranostics

Neoantigens play a pivotal role in the field of tumour therapy, encompassing the stimulation of anti-tumour immune response and the enhancement of tumour targeting capability. Nonetheless, numerous factors directly influence the effectiveness of neoantigens in bolstering anti-tumour immune responses, including neoantigen quantity and specificity, uptake rates by antigen-presenting cells (APCs), residence duration within the tumour microenvironment (TME), and their ability to facilitate the maturation of APCs for immune response activation. Nanotechnology assumes a significant role in several aspects, including facilitating neoantigen release, promoting neoantigen delivery to antigen-presenting cells, augmenting neoantigen uptake by dendritic cells, shielding neoantigens from protease degradation, and optimizing interactions between neoantigens and the immune system. Consequently, the development of nanotechnology synergistically enhances the efficacy of neoantigens in cancer theranostics. In this review, we provide an overview of neoantigen sources, the mechanisms of neoantigen-induced immune responses, and the evolution of precision neoantigen-based nanomedicine. This encompasses various therapeutic modalities, such as neoantigen-based immunotherapy, phototherapy, radiotherapy, chemotherapy, chemodynamic therapy, and other strategies tailored to augment precision in cancer therapeutics. We also discuss the current challenges and prospects in the application of neoantigen-based precision nanomedicine, aiming to expedite its clinical translation.

Mn(iii)-mediated carbon-centered radicals generate an enhanced immunotherapeutic effect

A strategy for designing cancer therapeutic nanovaccines based on immunogenic cell death (ICD)-inducing therapeutic modalities is particularly attractive for optimal therapeutic efficacy. In this work, a highly effective cancer therapeutic nanovaccine (denoted as MPL@ICC) based on immunogenic photodynamic therapy (PDT) was rationally designed and fabricated. MPL@ICC was composed of a nanovehicle of MnO2 modified with a host-guest complex using amino pillar[6]arene and lactose-pyridine, a prodrug of isoniazid (INH), and chlorine e6 (Ce6). The nanovaccine exhibited excellent biosafety, good targeting ability to hepatoma cells and enrichment at tumor sites. Most importantly, it could modulate the tumor microenvironment (TME) to facilitate the existence of Mn(iii) and Mn(iii)-mediated carbon-centered radical generation with INH released from the prodrug in situ to further strengthen ICD. This is the first report on Mn(iii)-mediated generation of carbon-centered radicals for successful anti-tumor immunotherapy using ICD, which provides a novel strategy for designing highly efficient cancer therapeutic nanovaccines.

Amplifying "eat me signal" by immunogenic cell death for potentiating cancer immunotherapy

Immunogenic cell death (ICD) is a unique mode of cell death, which can release immunogenic damage-associated molecular patterns (DAMPs) and tumor-associated antigens to trigger long-term protective antitumor immune responses. Thus, amplifying "eat me signal" during tumor ICD cascade is critical for cancer immunotherapy. Some therapies (radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), etc.) and inducers (chemotherapeutic agents, etc.) have enabled to initiate and/or facilitate ICD and activate antitumor immune responses. Recently, nanostructure-based drug delivery systems have been synthesized for inducing ICD through combining treatment of chemotherapeutic agents, photosensitizers for PDT, photothermal transformation agents for PTT, radiosensitizers for radiotherapy, etc., which can release loaded agents at an appropriate dosage in the designated place at the appropriate time, contributing to higher efficiency and lower toxicity. Also, immunotherapeutic agents in combination with nanostructure-based drug delivery systems can produce synergetic antitumor effects, thus potentiating immunotherapy. Overall, our review outlines the emerging ICD inducers, and nanostructure drug delivery systems loading diverse agents to evoke ICD through chemoradiotherapy, PDT, and PTT or combining immunotherapeutic agents. Moreover, we discuss the prospects and challenges of harnessing ICD induction-based immunotherapy, and highlight the significance of multidisciplinary and interprofessional collaboration to promote the optimal translation of this treatment strategy.

Enhancing Cancer Chemo-Immunotherapy: Innovative Approaches for Overcoming Immunosuppression by Functional Nanomaterials

Chemotherapy is a critical modality in cancer therapy to combat malignant cell proliferation by directly attacking cancer cells and inducing immunogenic cell death, serving as a vital component of multi-modal treatment strategies for enhanced therapeutic outcomes. However, chemotherapy may inadvertently contribute to the immunosuppression of the tumor microenvironment (TME), inducing the suppression of antitumor immune responses, which can ultimately affect therapeutic efficacy. Chemo-immunotherapy, combining chemotherapy and immunotherapy in cancer treatment, has emerged as a ground-breaking approach to target and eliminate malignant tumors and revolutionize the treatment landscape, offering promising, durable responses for various malignancies. Notably, functional nanomaterials have substantially contributed to chemo-immunotherapy by co-delivering chemo-immunotherapeutic agents and modulating TME. In this review, recent advancements in chemo-immunotherapy are thus summarized to enhance treatment effectiveness, achieved by reversing the immunosuppressive TME (ITME) through the exploitation of immunotherapeutic drugs, or immunoregulatory nanomaterials. The effects of two-way immunomodulation and the causes of immunoaugmentation and suppression during chemotherapy are illustrated. The current strategies of chemo-immunotherapy to surmount the ITME and the functional materials to target and regulate the ITME are discussed and compared. The perspective on tumor immunosuppression reversal strategy is finally proposed.

Cellular-Membrane-Derived Vesicles for Cancer Immunotherapy

The medical community is constantly searching for new and innovative ways to treat cancer, and cellular-membrane-derived artificial vesicles are emerging as a promising avenue for cancer immunotherapy. These vesicles, which are derived from mammal and bacteria cell membranes, offer a range of benefits, including compatibility with living organisms, minimal immune response, and prolonged circulation. By modifying their surface, manipulating their genes, combining them with other substances, stimulating them externally, and even enclosing drugs within them, cellular vesicles have the potential to be a powerful tool in fighting cancer. The ability to merge drugs with diverse compositions and functionalities in a localized area is particularly exciting, as it offers a way to combine different immunotherapy treatments for maximum impact. This review contains information on the various sources of these vesicles and discusses some recent developments in cancer immunotherapy using this promising technology. While there are still obstacles to overcome, the possibilities for cellular vesicles in cancer treatment are truly exciting.

Ultrasound-activated nanosonosensitizer for oxygen/sulfate dual-radical nanotherapy

An all-in-one therapy for cooperatively fighting cancer, infection and boosting wound repair is exceedingly demanded for patients with advanced superficial cancers or after surgical intervention to avoid multiple drug abuse and resultant adverse effects. Here, the ultrasound-activated nanosonosensitizer PHMP that integrated peroxymonosulfate (PMS) into the Pd-catalyzed hydrogenated mesoporous titanium dioxide (PHM) was dexterously designed for combined therapy of cancer and infected wound based on oxygen/sulfate dual-radical nanotherapy. Firstly, the PHM with single crystal structure and abundant oxygen deficiencies exhibited excellent ultrasound-excited reactive oxygen species (ROS) production for enhanced sonodynamic therapy (SDT) under the support of Pd nanozyme-mediated O2 supply. Simultaneously, the physically targeted ultrasound irradiation effectively transformed PMS loaded in the hollow cavities into distinct sulfate radical (•SO4-) with longer half-life and stronger oxidation, which remarkably enhanced the therapeutic efficacy of PHM-mediated SDT for cancer and bacteria. In addition, by embedding PHMP into the hydrogel, the enrichment of PHMP in the focal site was guaranteed, and meanwhile a moist and ventilated environment was created to speed up wound repair. The study broadens the potential of •SO4- in the therapeutic fields and contributes a simple and appealing tactic for the comprehensive treatment of cancer, infection and wound repair.

Three Strategies in Engineering Nanomedicines for Tumor Microenvironment-Enabled Phototherapy

Canonical phototherapeutics have several limitations, including a lack of tumor selectivity, nondiscriminatory phototoxicity, and tumor hypoxia aggravation. The tumor microenvironment (TME) is characterized by hypoxia, acidic pH, and high levels of H2 O2 , GSH, and proteases. To overcome the shortcomings of canonical phototherapy and achieve optimal theranostic effects with minimal side effects, unique TME characteristics are employed in the development of phototherapeutic nanomedicines. In this review, the effectiveness of three strategies for developing advanced phototherapeutics based on various TME characteristics is examined. The first strategy involves targeted delivery of phototherapeutics to tumors with the assistance of TME-induced nanoparticle disassembly or surface modification. The second strategy involves near-infrared absorption increase-induced phototherapy activation triggered by TME factors. The third strategy involves enhancing therapeutic efficacy by ameliorating TME. The functionalities, working principles, and significance of the three strategies for various applications are highlighted. Finally, possible challenges and future perspectives for further development are discussed.

Nanotechnology-Assisted Immunogenic Cell Death for Effective Cancer Immunotherapy

Tumor vaccines have been used to treat cancer. How to efficiently induce tumor-associated antigens (TAAs) secretion with host immune system activation is a key issue in achieving high antitumor immunity. Immunogenic cell death (ICD) is a process in which tumor cells upon an external stimulus change from non-immunogenic to immunogenic, leading to enhanced antitumor immune responses. The immune properties of ICD are damage-associated molecular patterns and TAA secretion, which can further promote dendritic cell maturation and antigen presentation to T cells for adaptive immune response provocation. In this review, we mainly summarize the latest studies focusing on nanotechnology-mediated ICD for effective cancer immunotherapy as well as point out the challenges.

Building in biologically appropriate multifunctionality in aqueous copper indium selenide-based quantum dots

Advanced nanoplatforms equipped with different functional moieties for theranostics hold appealing promise for reshaping precision medicine. The reliable construction of an individual nanomaterial with intrinsic near-infrared (NIR) photofunction and magnetic domains is much desired but largely unexplored in a direct aqueous synthesis system. Herein, we develop an aqueous phase synthetic strategy for Mn2+ doping of ZnS shell grown on Zn-Cu-In-Se core quantum dots (ZCISe@ZnS:Mn QDs), providing the optimal NIR fluorescence quantum efficiency of up to 18.9% and meanwhile efficiently introducing paramagnetic domains. The relaxometric properties of the water-soluble Mn-doped QDs make them desirable for both the longitudinal and transverse (T1 and T2) magnetic resonance (MR) contrast enhancement due to the shell lattice-doped Mn2+ ions with slow tumbling rates and favoured spin-proton dipolar interactions with surrounding water molecules. Surprisingly, the incorporation of Mn2+ ions into the shell is found to significantly enhance the production of reactive oxygen species (ROS) by combining both the chemodynamic and photodynamic processes upon NIR light irradiation, showing great potential for efficient photo-assisted ablation of cancer cells. Furthermore, a broad-spectrum excitation range beneficial for bright NIR fluorescence imaging of breast cancer has been proven and offers high flexibility in the choice of incident light sources. Multiparametric MR imaging of the brain has also been successfully demonstrated in vivo.

Engineering a facile and versatile nanoplatform to facilitate the delivery of multiple agents for targeted breast cancer chemo-immunotherapy

There is growing evidence showing that single administration of immunotherapeutic agents has limited efficacy in a number of cancer patients mainly due to tumor heterogeneity and immunosuppressive tumor microenvironment. In this study, a novel nanoparticle-based strategy was applied to achieve efficient tumor-targeted therapy by combining chemotherapeutic agents, i.e., doxorubicin (Dox) and melittin (Mel), with an immune checkpoint inhibitor (PD-L1 DsiRNA). The proposed nanoparticle was prepared by the formation of a complex between Mel and PD-L1 DsiRNA (Dicer-substrate short-interfering RNA), followed by the loading of Dox. The surface of the resultant particles (DoxMel/PD-L1 DsiRNA) was then modified with hyaluronic acid (HA) to increase their stability and distribution. In addition, HA can also act as a tumor-targeting agent through binding to its receptor CD44 on the surface of cancer cells. We demonstrated that the surface engineering of DoxMel/PD-L1 DsiRNA with HA significantly enhances its specificity towards breast cancer cells. Moreover, we observed a noticeable reduction in PD-L1 expression together with a synergistic effect of Dox and Mel on killing cancer cells and inducing immunogenic cell death, leading to significantly diminished tumor growth in 4T1-breast tumor bearing Balb/c mice, improved survival rate and extensive infiltration of immune cells including cytotoxic T cells into the tumor microenvironment. Safety analysis revealed that there is no significant toxicity associated with the developed nanoparticle. All in all, the proposed targeted combination treatment strategy can be considered as a useful method to reduce cancer-associated mortality.