A Tailored Multifunctional Anticancer Nanodelivery System for Ruthenium-Based Photosensitizers: Tumor Microenvironment Adaption and Remodeling

Ferrocene Derivatives for Photothermal Applications

Ferrocene (Fc) and Fc derivatives have gained popularity in recent years due to their unique structure and characteristics. Among Fc's diverse performances, photothermal conversion, as a primary source of energy conversion, has sparked substantial study attention. This Review summaries Fc and Fc derivatives with photothermal characteristics, as well as their applications developed recently. First, methods for the synthesis of Fc-based materials are systematically discussed. Then, the photothermal conversion mechanism based on nonradiative relaxation is summarized. Furthermore, the most recent advances in Fc-based materials in photothermal applications are described, including photothermal degradation, photothermal antibacterial, photothermal therapies, photothermal catalysis, solar-driven water production, and photothermal CO2 separation. Finally, a summary and insights on the photothermal application of Fc-based materials are provided. This paper seeks to provide researchers with a better knowledge of photothermal behavior while also highlighting the potential of Fc and its derivatives in photothermal fields.

Biodegradable Osmium Nanoantidotes for Photothermal-/Chemo- Combined Treatment and to Prevent Chemotherapy-Induced Acute Kidney Injury

Acute kidney injury (AKI) is a common adverse event in chemotherapy patients. AKI is accompanied by the generation of reactive oxygen species (ROS) and inflammation. Therefore, the management of ROS and inflammation is a potential strategy for AKI mitigation. Herein, polyethylene glycol-coated osmium nanozyme-based antidotes (Os) are developed for imaging-guided photothermal therapy (PTT) in combination with cisplatin (Pt); while, avoiding AKI induced by high-dose Pt. Os nanoantidotes can enhance the efficiency of tumor treatment during combined PTT and chemotherapy and inhibit tumor metastasis by improving the hypoxic and inflammatory tumor microenvironment. Os nanoantidotes preferentially accumulate in the kidney because of their 2-nm size distribution; and then, regulate inflammation by scavenging ROS and generating oxygen to alleviate Pt-induced AKI. Os nanoantidotes can be cleared from the kidneys by urine excretion but can be degraded under hydrogen peroxide stimulation, reducing the bio-retention of these compounds. By integrating PTT with inflammatory regulation, Os nanoantidotes have the potential to reduce the side effects of chemotherapy, offering an alternative route for the clinical management of cancer patients with chemotherapy-induced AKI.

Iridium nanozyme-mediated photoacoustic imaging-guided NIR-II photothermal therapy and tumor microenvironment regulation for targeted eradication of cancer stem cells

Cancer stem cells (CSCs) are found in many solid tumors, which play decisive roles in the occurrence, recurrence and metastasis of tumors. However, drugs are difficult to kill CSCs due to their limited number and location in oxygen-deprived tissue far from the blood vessels. Meanwhile, the survival and stemness maintenance of CSCs strongly depend on the tumor microenvironment (TME). Herein, we developed a CD44 antibody modified iridium nanosheet with enzyme-like activity (defined as Ir Nts-Ab) that effectively eradicates CSCs for cancer therapy. We observe that Ir Nts-Ab can enrich tumor tissues to remove excessive reactive oxygen species and produce oxygen, thus alleviating hypoxia and the inflammatory TME to reduce the proportion of CSCs and inhibit metastasis. In addition, Ir Nts-Ab targets CSCs and normal cancer cells with near infrared II-region photothermal therapy (NIR-II PTT), and is easily taken up by CSCs due to recognition of the CD44 proteins. Moreover, photoacoustic imaging helps monitor drug accumulation and hypoxic TME improvement in tumor tissue. Importantly, Ir Nts-Ab has good biological safety, making it suitable for biomedical applications. This iridium nanozyme based on TME regulation as well as NIR-II PTT will be a promising strategy for the treatment of cancer. STATEMENT OF SIGNIFICANCE: Cancer stem cells (CSCs) are key factors that make tumors difficult to eradicate, and strongly depend on the hypoxic tumor microenvironment (TME), which plays a crucial role in the occurrence and metastasis of tumors. Herein, an antibody modified iridium nanosheet (definition as Ir Nts-Ab) was developed for targeted eradication of CSCs by photoacoustic imaging guided photothermal therapy (PTT) and TME regulation. Ir Nts-Ab with catalase-like activity could inhibit HIF-1α by producing oxygen, thus effectively reducing the proportion of CSCs and inhibiting tumor metastasis. Additionally, Ir Nts-Ab achieved the eradication of CSCs by PTT, and eliminated reactive oxygen species to decrease the inflammatory response, resulting in reduced tumor metastasis, which was promising for the cure of solid tumors in the clinics.

Nanomedicine Strategies in Conquering and Utilizing the Cancer Hypoxia Environment

Cancer with a complex pathological process is a major disease to human welfare. Due to the imbalance between oxygen (O2) supply and consumption, hypoxia is a natural characteristic of most solid tumors and an important obstacle for cancer therapy, which is closely related to tumor proliferation, metastasis, and invasion. Various strategies to exploit the feature of tumor hypoxia have been developed in the past decade, which can be used to alleviate tumor hypoxia, or utilize the hypoxia for targeted delivery and diagnostic imaging. The strategies to alleviate tumor hypoxia include delivering O2, in situ O2 generation, reprogramming the tumor vascular system, decreasing O2 consumption, and inhibiting HIF-1 related pathways. On the other side, hypoxia can also be utilized for hypoxia-responsive chemical construction and hypoxia-active prodrug-based strategies. Taking advantage of hypoxia in the tumor region, a number of methods have been applied to identify and keep track of changes in tumor hypoxia. Herein, we thoroughly review the recent progress of nanomedicine strategies in both conquering and utilizing hypoxia to combat cancer and put forward the prospect of emerging nanomaterials for future clinical transformation, which hopes to provide perspectives in nanomaterials design.

Platinum based theranostics nanoplatforms for antitumor applications

Platinum (Pt) based nanoplatforms are biocompatible nanoagents with photothermal antitumor performance, while exhibiting excellent radiotherapy sensitization properties. Pt-nanoplatforms have extensive research prospects in the realm of cancer treatment due to their highly selective and minimally invasive treatment mode with low damage, and integrated diagnosis and treatment with image monitoring and collaborative drug delivery. Platinum based anticancer chemotherapeutic drugs can kill tumor cells by damaging DNA through chemotherapy. Meanwhile, Pt-nanoplatforms also have good electrocatalytic activity, which can mediate novel electrodynamic therapy. Simultaneously, Pt(II) based compounds also have potential as photosensitizers in photodynamic therapy for malignant tumors. Pt-nanoplatforms can also modulate the immunosuppressive environment and synergistically ablate tumor cells in combination with immune checkpoint inhibitors. This article reviews the research progress of platinum based nanoplatforms in new technologies for cancer therapy, starting from widely representative examples of platinum based nanoplatforms in chemotherapy, electrodynamic therapy, photodynamic therapy, photothermal therapy, and immunotherapy. Finally, multimodal imaging techniques of platinum based nanoplatforms for biomedical diagnosis are briefly discussed.

Self-Assembled Carrier-Free Nanodrugs for Starvation Therapy-Amplified Photodynamic Therapy of Cancer

Traditional starvation treatment strategies, which involve glucose oxidase and drug-induced thrombi, often suffer from aggravated tumor hypoxia and have failed to improve antitumor efficacy in combination with oxygen-dependent photodynamic therapy (PDT). Herein, glucose transporter 1 inhibitor genistein (Gen) and photosensitizer chlorin e6 (Ce6) are integrated to construct carrier-free self-assembled nanoparticles defined as GC NPs, for starvation therapy-amplified PDT of tumor. GC NPs with regular morphology and stability are screened out by component adjustment, while the function of each component is preserved. On the one hand, Gen released from GC NPs can cut off tumor glucose uptake by inhibiting the glucose transporter 1 to restrict tumor growth, achieving starvation therapy. On the other hand, they are able to decrease the amount of oxygen consumed by tumor respiration and amplify the therapeutic effect of PDT. In vitro and in vivo experiments verify the excellent synergistic antitumor therapeutic efficacy of GC NPs without any apparent toxicity. Moreover, fluorescence and photoacoustic imaging provide guidance for in vivo PDT, demonstrating the excellent tumor enrichment efficiency of GC NPs. It is believed that this starvation therapy-amplified PDT strategy by carrier-free self-assembled GC NPs holds promising clinical prospects.

Supramolecular nanomedicines based on host-guest interactions of cyclodextrins

In the biomedical and pharmaceutical fields, cyclodextrin (CD) is undoubtedly one of the most frequently used macrocyclic compounds as the host molecule because it has good biocompatibility and can increase the solubility, bioavailability, and stability of hydrophobic drug guests. In this review, we generalized the unique properties of CDs, CD-related supramolecular nanocarriers, supramolecular controlled release systems, and targeting systems based on CDs, and introduced the paradigms of these nanomedicines. In addition, we also discussed the prospects and challenges of CD-based supramolecular nanomedicines to facilitate the development and clinical translation of these nanomedicines.

Ferrocene-Based Drugs, Delivery Nanomaterials and Fenton Mechanism: State of the Art, Recent Developments and Prospects

Ferrocene has been the most used organometallic moiety introduced in organic and bioinorganic drugs to cure cancers and various other diseases. Following several pioneering studies, two real breakthroughs occurred in 1996 and 1997. In 1996, Jaouen et al. reported ferrocifens, ferrocene analogs of tamoxifen, the chemotherapeutic for hormone-dependent breast cancer. Several ferrocifens are now in preclinical evaluation. Independently, in 1997, ferroquine, an analog of the antimalarial drug chloroquine upon the introduction of a ferrocenyl substituent in the carbon chain, was reported by the Biot-Brocard group and found to be active against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Ferroquine, in combination with artefenomel, completed phase IIb clinical evaluation in 2019. More than 1000 studies have been published on ferrocenyl-containing pharmacophores against infectious diseases, including parasitic, bacterial, fungal, and viral infections, but the relationship between structure and biological activity has been scarcely demonstrated, unlike for ferrocifens and ferroquines. In a majority of ferrocene-containing drugs, however, the production of reactive oxygen species (ROS), in particular the OH. radical, produced by Fenton catalysis, plays a key role and is scrutinized in this mini-review, together with the supramolecular approach utilizing drug delivery nanosystems, such as micelles, metal-organic frameworks (MOFs), polymers, and dendrimers.

Integrated supramolecular nanovalves for photothermal augmented chemodynamic therapy through strengthened amplification of oxidative stress

The amplified oxidative stress strategy has been emerged as one promising method to enhance the chemodynamic therapy (CDT) efficacy due to the H₂O₂ up-regulation and glutathione (GSH) down-regulation behavior in tumor cells. However, how to further achieve the satisfied CDT efficacy is still a big challenge. In this paper, the supramolecular nanovalves (SNs) with oxidative amplification agents cinnamaldehyde-(phenylboronic acid pinacol ester) conjugates (CA-BE) encapsulated inside were developed to accelerate and amplify the generation of ·OH and consumption of GSH while augmenting the CDT efficacy. SNs were obtained through ferrocene/Au modified mesoporous silica nanoparticles (MSN@Au-Fc) and active targeting β-cyclodextrin modified hyaluromic acid (HA-CD). After CD44 receptor-mediated cellular internalization, the CA-BE were released to elevate H₂O₂ amount and consume GSH for the desired generation of higher cytotoxic hydroxyl radicals (·OH). Moreover, the NIR-activated MSN@Au-Fc can increase the temperature for the accelerated and amplified oxidative stress. As such, the therapeutic efficacy of our synthesized CA-BE and the accompanied hyperthermia were augmented toward synergistically inhibiting tumor growth.

A Leaking-Proof Theranostic Nanoplatform for Tumor-Targeted and Dual-Modality Imaging-Guided Photodynamic Therapy

Objective: A protein-based leaking-proof theranostic nanoplatform for dual-modality imaging-guided tumor photodynamic therapy (PDT) has been designed. Impact Statement: A site-specific conjugation of chlorin e6 (Ce6) to ferrimagnetic ferritin (MFtn-Ce6) has been constructed to address the challenge of unexpected leakage that often occurs during small-molecule drug delivery. Introduction: PDT is one of the most promising approaches for tumor treatment, while a delivery system is typically required for hydrophobic photosensitizers. However, the nonspecific distribution and leakage of photosensitizers could lead to insufficient drug accumulation in tumor sites. Methods: An engineered ferritin was generated for site-specific conjugation of Ce6 to obtain a leaking-proof delivery system, and a ferrimagnetic core was biomineralized in the cavity of ferritin, resulting in a fluorescent ferrimagnetic ferritin nanoplatform (MFtn-Ce6). The distribution and tumor targeting of MFtn-Ce6 can be detected by magnetic resonance imaging (MRI) and fluorescence imaging (FLI). Results: MFtn-Ce6 showed effective dual-modality MRI and FLI. A prolonged in vivo circulation and increased tumor accumulation and retention of photosensitizer was observed. The time-dependent distribution of MFtn-Ce6 can be precisely tracked in real time to find the optimal time window for PDT treatment. The colocalization of ferritin and the iron oxide core confirms the high stability of the nanoplatform in vivo. The results showed that mice treated with MFtn-Ce6 exhibited marked tumor-suppressive activity after laser irradiation. Conclusion: The ferritin-based leaking-proof nanoplatform can be used for the efficient delivery of the photosensitizer to achieve an enhanced therapeutic effect. This method established a general approach for the dual-modality imaging-guided tumor delivery of PDT agents.

Polydopamine-functionalized selenium nanoparticles as an efficient photoresponsive antibacterial platform

A photoresponsive therapeutic antibacterial platform was designed and constructed using polydopamine-functionalized selenium nanoparticles as a carrier loaded with indocyanine green (Se@PDA-ICG). The therapeutic platform was confirmed by characterization and the antibacterial activity of Se@PDA-ICG against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was investigated. Under 808 nm laser irradiation, the antibacterial rate of Se@PDA-ICG against E. coli and S. aureus was 100% at 125 μg mL-1. Furthermore, in a mouse wound infection model, the wound closure rate of the Se@PDA-ICG photoresponse group was 88.74% compared with 45.8% for the control group after 8 days of treatment, indicating that it could effectively kill bacteria and dramatically accelerate the wound healing process. These results suggested that Se@PDA-ICG could be a promising photo-activated antibacterial candidate material for biomedical applications.

Photodynamic therapy: Innovative approaches for antibacterial and anticancer treatments

Photodynamic therapy is an alternative treatment mainly for cancer but also for bacterial infections. This treatment dates back to 1900 when a German medical school graduate Oscar Raab found a photodynamic effect while doing research for his doctoral dissertation with Professor Hermann von Tappeiner. Unexpectedly, Raab revealed that the toxicity of acridine on paramecium depends on the intensity of light in his laboratory. Photodynamic therapy is therefore based on the administration of a photosensitizer with subsequent light irradiation within the absorption maxima of this substance followed by reactive oxygen species formation and finally cell death. Although this treatment is not a novelty, there is an endeavor for various modifications to the therapy. For example, selectivity and efficiency of the photosensitizer, as well as irradiation with various types of light sources are still being modified to improve final results of the photodynamic therapy. The main aim of this review is to summarize anticancer and antibacterial modifications, namely various compounds, approaches, and techniques, to enhance the effectiveness of photodynamic therapy.

A Phase-Change Mediated Intelligent Nanoplatform for Chemo/Photothermal/Photodynamic Therapy of Cancer

Up to now, chemotherapy is still the main strategy for cancer treatment. However, the emergence of chemo-resistance and systemic side effects often seriously affects the treatment and prognosis. Herein, an intelligent nanoplatform based on dendritic mesoporous organosilica nanoparticles (DMON) is constructed. The encapsulated phase-change material, 1-tetradecanol (TD) can serve as a "doorkeeper" and enable the responsive release of drugs based on the temperature changes. Meanwhile, polyethylene glycol (PEG) is used to improve the dispersibility and biocompatibility. Cisplatin is chosen as the model of chemotherapy drug, which is co-loaded with indocyanine green (ICG) in DMON to produce DMON-PEG-cisplatin/ICG-TD (DPCIT). Exciting, the hyperthermia and reactive oxygen species induced by ICG under the NIR-laser irradiation will initiate a phase transition of TD to release cisplatin, thus leading a combined therapy (chemo/photothermal/photodynamic therapy). The results indicated that under laser irradiation, DPCIT can kill cancer cells and inhibit tumor growth efficiently. In addition, the designed nanoplatform reveals minimal systemic toxicity in vivo, in contrast, the distinct liver damage can be observed by the direct treatment of cisplatin. Overall, this research may provide a general approach for the targeted delivery and controlled release of chemotherapy drugs to realize a cooperatively enhanced multimodal tumor therapy.

Iridium Tungstate Nanozyme-Mediated Hypoxic Regulation and Anti-inflammation for Duplex Imaging Guided Photothermal Therapy of Metastatic Breast Tumors

Metastasis of breast cancer is key to poor prognosis and high mortality. However, the excess reactive oxygen species (ROS) and inflammatory response induced by photothermal therapy (PTT) further aggravate tumor metastasis. Meanwhile, the hypoxic tumor microenvironment promotes tumor cells to metastasize to distant organs. Herein, the intrinsic limitations of PTT for metastatic tumor have been addressed by fabricating polyethylene glycol modified iridium tungstate (IrWO_x-PEG) nanoparticles. The as-designed IrWO_x-PEG nanoparticles displayed good photothermal (PT) conversion ability for duplex photoacoustic/PT imaging guided PTT and multienzyme mimetic feature for broad-spectrum ROS scavenging. On the one hand, IrWO_x-PEG effectively removed excess ROS generated during PTT and reduced inflammation. On the other hand, owing to the catalase-like activity, it preferentially triggered the catalytic production of oxygen by decomposing ROS, leading to relieving of the hypoxic microenvironment. Hence, under bimodal imaging guidance, IrWO_x-PEG induced PTT completely eliminated in situ breast cancer in 4T1 tumor-bearing mice with no observable system toxicity, as well as further restricting tumor metastasis to other vital organs (lungs) by ROS scavenging, anti-inflammation, and regulating hypoxic microenvironment. We anticipate that this work will lead to new treatment strategies for other metastatic cancers.

Self-Amplifying Iridium(III) Photosensitizer for Ferroptosis-Mediated Immunotherapy Against Transferrin Receptor-Overexpressing Cancer

Photoimmunotherapy is attractive for cancer treatment due to its spatial controllability and sustained responses. This work presents a ferrocene-containing Ir(III) photosensitizer (IrFc1) that can bind with transferrin and be transported into triple-negative breast cancer (TNBC) cells via a transferrin receptor-mediated pathway. When the ferrocene in IrFc1 is oxidized by reactive oxygen species, its capability to photosensitize both type I (electron transfer) and type II (energy transfer) pathways is activated through a self-amplifying process. Upon irradiation, IrFc1 induces the generation of lipid oxidation to cause ferroptosis in TNBC cells, which promotes immunogenic cell death (ICD) under both normoxia and hypoxia. In vivo, IrFc1 treatment elicits a CD8⁺ T-cell response, which activates ICD in TNBC resulting in enhanced anticancer immunity. In summary, this work reports a small molecule-based photosensitizer with enhanced cancer immunotherapeutic properties by eliciting ferroptosis through a self-amplifying process.

Biomedical engineered nanomaterials to alleviate tumor hypoxia for enhanced photodynamic therapy

Photodynamic therapy (PDT), as a highly selective, widely applicable, and non-invasive therapeutic modality that is an alternative to radiotherapy and chemotherapy, is extensively applied to cancer therapy. Practically, the efficiency of PDT is severely hindered by the existence of hypoxia in tumor tissue. Hypoxia is a typical hallmark of malignant solid tumors, which remains an essential impediment to many current treatments, thereby leading to poor clinical prognosis after therapy. To address this issue, studies have been focused on modulating tumor hypoxia to augment the therapeutic efficacy. Although nanomaterials to relieve tumor hypoxia for enhanced PDT have been demonstrated in many research articles, a systematical summary of the role of nanomaterials in alleviating tumor hypoxia is scarce. In this review, we introduced the mechanism of PDT, and the involved therapeutic modality of PDT for ablation of tumor cells was specifically summarized. Moreover, current advances in nanomaterials-mediated tumor oxygenation via oxygen-carrying or oxygen-generation tactics to alleviate tumor hypoxia are emphasized. Based on these considerable summaries and analyses, we proposed some feasible perspectives on nanoparticle-based tumor oxygenation to ameliorate the therapeutic outcomes, which may provide some detailed information in designing new oxygenation nanomaterials in this burgeneous field.

Platinum-based nanocomposites loaded with MTH1 inhibitor amplify oxidative damage for cancer therapy

Photodynamic therapy (PDT) is a promising therapeutic strategy for tumor ablation by generating highly toxic reactive oxygen species (ROS) to damage DNA and other biomacromolecules. However, the local hypoxic microenvironment of the tumor and the presence of ROS-defensing system, such as the mobilization of mutt homolog 1 (MTH1) to sanitize ROS-oxidized nucleotide pool, severely limit the efficiency of PDT. Therefore, a novel tumor ablation strategy was developed that not only focused on the enhancement of ROS generation but also weakened the ROS-defensing system by inhibiting MTH1 enzyme activity. In our work, a simple one-step reduction approach was applied to enable platinum nanoparticles (Pt NPs) with catalase activity to grow in situ in the nanochannels of mesoporous silica nanoparticles (MSNs). After physical encapsulation of photosensitizer chlorin e6 (Ce6) and MTH1 inhibitor TH588, the drug loading nanoplatform was modified with an arginine-glycine-aspartic acid (RGD) functionalized liposome shell, resulting in the fabrication of amplified oxidative damage nanoplatform MSN-Pt@Ce6/TH588 @Liposome-RGD (MPCT@Li-R). The prepared MPCT@Li-R NPs could continuously catalyze the decomposition of hydrogen peroxide (H₂O₂) into oxygen (O₂) in tumor, thus promoting the generation of singlet oxygen during PDT process for improved oxidative damage of bases. Simultaneously, acid responsive released TH588 hindered MTH1-mediated scavenging of oxidative bases, further aggravating DNA oxidative damage. Consequently, this cascade therapy strategy exhibited excellent tumor suppression efficiency both in vitro and in vivo.

Engineering cancer cell membrane-camouflaged metal complex for efficient targeting therapy of breast cancer

Background

Cancer cell membrane-camouflaged nanotechnology for metal complex can enhance its biocompatibility and extend the effective circulation time in body. The ruthenium polypyridyl complex (RuPOP) has extensive antitumor activity, but it still has disadvantages such as poor biocompatibility, lack of targeting, and being easily metabolized by the organism. Cancer cell membranes retain a large number of surface antigens and tumor adhesion molecules CD47, which can be used to camouflage the metal complex and give it tumor homing ability and high biocompatibility.

Results

Therefore, this study provides an electrostatic adsorption method, which uses the electrostatic interaction of positive and negative charges between RuPOP and cell membranes to construct a cancer cell membrane-camouflaged nano-platform (RuPOP@CM). Interestingly, RuPOP@CM maintains the expression of surface antigens and tumor adhesion molecules, which can inhibit the phagocytosis of macrophage, reduce the clearance rate of RuPOP, and increase effective circulation time, thus enhancing the accumulation in tumor sites. Besides, RuPOP@CM can enhance the activity of cellular immune response and promote the production of inflammatory cytokines including TNF-α, IL-12 and IL-6, which is of great significance in treatment of tumor. On the other hand, RuPOP@MCM can produce intracellular ROS overproduction, thereby accelerating the apoptosis and cell cycle arrest of tumor cells to play an excellent antitumor effect in vitro and in vivo.

Conclusion

In brief, engineering cancer cell membrane-camouflaged metal complex is a potential strategy to improve its biocompatibility, biological safety and antitumor effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01593-5.

Self-assembled iRGD-R7-LAHP-M nanoparticle induced sufficient singlet oxygen and enhanced tumor penetration immunological therapy

The generation of singlet oxygen (¹O₂) using photodynamic therapy (PDT) is limited by the hypoxia of the tumor microenvironment and the depth of external light penetration because it depends on the precise cooperation between the photosensitizers, oxygen, and light. Herein, we report a self-sufficient ¹O₂ nanoreactor with enhanced penetration into deep tumors for cancer therapy. Linoleic acid hydroperoxide (LAHP) is coordinated with transition metal ions (Cu²⁺/Fe³⁺) to prepare linoleic acid hydroperoxide metal complex nanoparticles (LAHP-M NPs). iRGD combined with R7 decoration endows the nanoparticles with tumor targeting and penetration ability. We show that the polypeptide carries the nanoparticles into deep tumors, and thereafter the nanoparticles are disassembled into LAHP and catalytical metal ions to produce ¹O₂ based on the Russell mechanism under the stimulation of acidic pH. The elevated ROS induces necrotic cell death in vitro and in vivo, and further causes immunogenic cell death (ICD). This study demonstrates the effectiveness of exploiting biochemical reactions as a spatial-temporal strategy to overcome the current limitations of photodynamic therapy.

Metal Peptide Conjugates in Cell and Tissue Imaging and Biosensing

Metal complex luminophores have seen dramatic expansion in application as imaging probes over the past decade. This has been enabled by growing understanding of methods to promote their cell permeation and intracellular targeting. Amongst the successful approaches that have been applied in this regard is peptide-facilitated delivery. Cell-permeating or signal peptides can be readily conjugated to metal complex luminophores and have shown excellent response in carrying such cargo through the cell membrane. In this article, we describe the rationale behind applying metal complexes as probes and sensors in cell imaging and outline the advantages to be gained by applying peptides as the carrier for complex luminophores. We describe some of the progress that has been made in applying peptides in metal complex peptide-driven conjugates as a strategy for cell permeation and targeting of transition metal luminophores. Finally, we provide key examples of their application and outline areas for future progress.

NIR-II Emissive Ru(II) Metallacycle Assisting Fluorescence Imaging and Cancer Therapy

Despite the success of emissive Ruthenium (Ru) agents in biomedicine, problems such as the visible-light excitation/emission and single chemo- or phototherapy modality still hamper their applications in deep-tissue imaging and efficient cancer therapy. Herein, an second nearinfrared window (NIR-II) emissive Ru(II) metallacycle (Ru1000, λ_em  = 1000 nm) via coordination-driven self-assembly is reported, which holds remarkable deep-tissue imaging capability (≈6 mm) and satisfactory chemo-phototherapeutic performance. In vitro results indicate Ru1000 displays promising cellular uptake, good cancer-cell selectivity, attractive anti-metastasis properties, and remarkable anticancer activity against various cancer cells, including cisplatin-resistant A549 cells (IC₅₀  = 3.4 × 10^-6  m vs 92.8 × 10^-6  m for cisplatin). The antitumor mechanism could be attributed to Ru1000-induced lysosomal membrane damage and mitochondrial-mediated apoptotic cell death. Furthermore, Ru1000 also allows the high-performance in vivo NIR-II fluorescence imaging-guided chemo-phototherapy against A549 tumors. This work may provide a paradigm for the development of long-wavelength emissive metallacycle-based agents for future biomedicine.

Enhanced delivery of theranostic liposomes through NO-mediated tumor microenvironment remodeling

Highly efficient delivery of nanoagents to the tumor region remains the primary challenge for cancer nanomedicine. Herein, we propose a NO-mediated tumor microenvironment (TME) remodeling strategy for the high-efficient delivery of nanoagents into tumor. Quantum dots (QDs) with bright fluorescence in the near-infrared IIb (NIR-IIb, 1500-1700 nm) window and high photothermal conversion efficiency were encapsulated into liposomes for the imaging-guided photothermal therapy (PTT) of tumor. The fabrication of PEG and arginine-glycine-aspartate (RGD) peptide on liposomes ensured the prolonged circulation in vivo and active targeting to tumor. Moreover, the loading of a natural NO generator L-arginine in liposomes realized the continuous generation of NO in the acidic TME. By co-localization fluorescence imaging and western blot of tumor tissue, we confirmed that the release of NO activated the expression of metalloproteinases in TME and further degraded Collagen I in the peripheral region of the tumor, thus removing the barrier for the permeation of liposomes. Attributed to the enhanced accumulation of liposomes inside the tumor, NIR IIb imaging-guided PTT was achieved with remarkable therapeutic efficacy.

An Enhanced Photothermal Therapeutic Iridium Hybrid Platform Reversing the Tumor Hypoxic Microenvironment

As hypoxia is closely associated with tumor progression, proliferation, invasion, metastasis, and strong resistance to therapy, regulating and overcoming the hypoxia tumor microenvironment are two increasingly important aspects of tumor treatment. Herein, we report a phototherapeutic platform that uses the organic photosensitizer diketopyrrolopyrrole (DPP) derivative and inorganic iridium salts (IrCl₃) with photothermal activity and the capacity to decompose H₂O₂ efficiently. The characterization of their photophysical properties proved that DPP-Ir nanoparticles are capable of remarkable near-infrared (NIR) absorption, and compared to DPP nanoparticles, the photothermal conversion efficiency (PCE) increases from 42.1% in DPP nanoparticles to 67.0% in DPP-Ir nanoparticles. The hybrid nanoparticles utilize the catalytic decomposition of endogenous H₂O₂ to produce oxygen for the downregulation of the hypoxia-inducible factor 1 subunit alpha (HIF-1α) protein, which could reverse the tumor hypoxic microenvironment. Benefiting from the excellent optical properties and good biocompatibility, the hybrid platform exhibits efficient photothermal therapeutic effects as well as good biological safety. In conclusion, such a hybrid platform could improve photothermal therapy against cancer.

Light amplified oxidative stress in tumor microenvironment by carbonized hemin nanoparticles for boosting photodynamic anticancer therapy

Photodynamic therapy (PDT), which utilizes light excite photosensitizers (PSs) to generate reactive oxygen species (ROS) and consequently ablate cancer cells or diseased tissue, has attracted a great deal of attention in the last decades due to its unique advantages. However, the advancement of PDT is restricted by the inherent characteristics of PS and tumor microenvironment (TME). It is urgent to explore high-performance PSs with TME regulation capability and subsequently improve the therapeutic outcomes. Herein, we reported a newly engineered PS of polymer encapsulated carbonized hemin nanoparticles (P-CHNPs) via a facile synthesis procedure for boosting photodynamic anticancer therapy. Solvothermal treatment of hemin enabled the synthesized P-CHNPs to enhance oxidative stress in TME, which could be further amplified under light irradiation. Excellent in vitro and in vivo PDT effects were achieved due to the improved ROS (hydroxyl radicals and singlet oxygen) generation efficiency, hypoxia relief, and glutathione depletion. Moreover, the superior in vitro and in vivo biocompatibility and boosted PDT effect make the P-CHNPs a potential therapeutic agent for future translational research.

Biotinylated curcumin as a novel chemosensitizer enhances naphthalimide-induced autophagic cell death in breast cancer cells

Achieving selective release of chemical anticancer agents and improving therapeutic efficacy has always been a hot spot in the field of cancer research, yet how to achieve this remains a great challenge. In this work, we constructed a novel chemical anticancer agent (named MCLOP) by introducing naphthalimide into the skeleton of methylene blue (MB). Under the stimulation by cellular hypochlorous acid (HClO) and visible light, selective release of active naphthalimide can be achieved within breast cancer cell lines, the release process of which can be tracked visually using near-infrared fluorescence of MB (685 nm). More importantly, we developed biotinylated curcumin (Cur-Bio) as a new chemosensitizer, which significantly enhanced the ability of MCLOP to induce autophagic cell death of breast cancer cells. This synergistic treatment strategy exhibited an excellent anti-proliferation effect on breast cancer cells in vitro, three-dimensional (3D) cell sphere model, and mouse tumor model in vivo. This work provides a new strategy for the treatment of breast cancer and also opens new opportunities for the efficient treatment of cancer with curcumin-based chemosensitizer.

Scaffold 3D-Printed from Metallic Nanoparticles-Containing Ink Simultaneously Eradicates Tumor and Repairs Tumor-Associated Bone Defects

Bone metastasis occurs in about 70% of breast cancer patients. The surgical resection of metastatic tumors often leads to bone erosion and destruction, which greatly hinders the treatment and prognosis of breast cancer patients with bone metastasis. Herein, a bifunctional scaffold 3D-printed from nanoink is fabricated to simultaneously eliminate the tumor cells and repair the tumor-associated bone defects. The metallic polydopamine (PDA) nanoparticles (FeMg-NPs) may effectively load and sustainably release the metal ions Fe³⁺ and Mg²⁺ in situ. Fe³⁺ exerts a chemodynamic therapy to synergize with the photothermal therapy induced by PDA with effective photothermal conversion under NIR laser, which efficiently eliminates the bone-metastatic tumor. Meanwhile, the sustained release of osteoinductive Mg²⁺ from the bony porous 3D scaffold enhances the new bone formation in the bone defects. Taken together, the implantation of scaffold (FeMg-SC) 3D-printed from the FeMg-NPs-containing nanoink provides a novel strategy to simultaneously eradicate bone-metastatic tumor and repair the tumor-associated bone defects.

Self-Cycling Free Radical Generator from LDH-Based Nanohybrids for Ferroptosis-Enhanced Chemodynamic Therapy

Nonapoptotic ferroptosis has been a novel form of programmed cell death, which provides a new solution to enrich the anticancer treatment efficacy of traditional apoptotic therapeutic modality. Herein, a novel nanohybrid is designed by loading the PEG-encapsulated Artemisinin (denoted as A@P) on the ultrathin MgFe-LDH nanosheets (denoted as uLDHs) for improved chemodynamic therapy (CDT). The A@P/uLDHs cannot only realize the self-assembly between the Art and carrier but also be regarded as free radical generator. A comprehensive mechanistic study suggests that this unique A@P/uLDHs is able to in situ activate Art and self-cycling generate toxic C-centered free radical inside the cancer cells, without depending on abundant H₂ O₂ , accompanied with diminished cancerous antioxidation by depleting glutathione (GSH). The accumulation of ROS and depletion of GSH can further oxidize unsaturated fatty acid to generate lipid peroxide, whose overexpression can induce cell ferroptosis accompanied by cellular iron homeostasis turbulence. Both in vitro and in vivo results exhibit that A@P/uLDHs are an efficient nanoagent for highly efficient ferroptosis-enhanced CDT treatment. This work imparts the promising new visions about the ferroptosis-enhanced CDT via fine regulation of material design for improved cancer treatments.

Multifaceted role of phyto-derived polyphenols in nanodrug delivery systems

As naturally occurring bioactive products, several lines of evidence have shown the potential of polyphenols in the medical intervention of various diseases, including tumors, inflammatory diseases, and cardiovascular diseases. Notably, owing to the particular molecular structure, polyphenols can combine with proteins, metal ions, polymers, and nucleic acids providing better strategies for polyphenol-delivery strategies. This contributes to the inherent advantages of polyphenols as important functional components for other drug delivery strategies, e.g., protecting nanodrugs from oxidation as a protective layer, improving the physicochemical properties of carbohydrate polymer carriers, or being used to synthesize innovative functional delivery vehicles. Polyphenols have emerged as a multifaceted player in novel drug delivery systems, both as therapeutic agents delivered to intervene in disease progression and as essential components of drug carriers. Although an increasing number of studies have focused on polyphenol-based nanodrug delivery including epigallocatechin-3-gallate, curcumin, resveratrol, tannic acid, and polyphenol-related innovative preparations, these molecules are not without inherent shortcomings. The active biochemical characteristics of polyphenols constitute a prerequisite to their high-frequency use in drug delivery systems and likewise to provoke new challenges for the design and development of novel polyphenol drug delivery systems of improved efficacies. In this review, we focus on both the targeted delivery of polyphenols and the application of polyphenols as components of drug delivery carriers, and comprehensively elaborate on the application of polyphenols in new types of drug delivery systems. According to the different roles played by polyphenols in innovative drug delivery strategies, potential limitations and risks are discussed in detail including the influences on the physical and chemical properties of nanodrug delivery systems, and their influence on normal physiological functions inside the organism.

Cu-Ferrocene-Functionalized CaO2 Nanoparticles to Enable Tumor-Specific Synergistic Therapy with GSH Depletion and Calcium Overload

The conversion of endogenous H2 O2 into toxic hydroxyl radical (• OH) via catalytic nanoparticles is explored for tumor therapy and received considerable success. The intrinsic characteristics of microenvironment in tumor cells, such as limited H2 O2 and overexpressed glutathione (GSH), hinder the intracellular • OH accumulation and thus weaken therapeutic efficacy considerably. In this study, fine CaO2 nanoparticles with Cu-ferrocene molecules at the surface (CaO2 /Cu-ferrocene) are successfully designed and synthesized. Under an acidic condition, the particles release Ca2+ ions and H2 O2 in a rapid fashion, while they can remain stable in neutral. In addition, agitated production of • OH occurs following the Fenton reaction of H2 O2 and ferrocene molecules, and GSH is consumed by Cu2+ ions to avoid the potential • OH consumption. More interestingly, in addition to the exogenous Ca2+ released by the particles, the enhanced • OH production facilitates intracellular calcium accumulation by regulating Ca2+ channels and pumps of tumor cells. It turns out that promoted • OH induction and intracellular calcium overload enable significant in vitro and in vivo antitumor phenomena.

Phenolic-enabled nanotechnology: versatile particle engineering for biomedicine

Phenolics are ubiquitous in nature and have gained immense research attention because of their unique physiochemical properties and widespread industrial use. In recent decades, their accessibility, versatile reactivity, and relative biocompatibility have catalysed research in phenolic-enabled nanotechnology (PEN) particularly for biomedical applications which have been a major benefactor of this emergence, as largely demonstrated by polydopamine and polyphenols. Therefore, it is imperative to overveiw the fundamental mechanisms and synthetic strategies of PEN for state-of-the-art biomedical applications and provide a timely and comprehensive summary. In this review, we will focus on the principles and strategies involved in PEN and summarize the use of the PEN synthetic toolkit for particle engineering and the bottom-up synthesis of nanohybrid materials. Specifically, we will discuss the attractive forces between phenolics and complementary structural motifs in confined particle systems to synthesize high-quality products with controllable size, shape, composition, as well as surface chemistry and function. Additionally, phenolic's numerous applications in biosensing, bioimaging, and disease treatment will be highlighted. This review aims to provide guidelines for new scientists in the field and serve as an up-to-date compilation of what has been achieved in this area, while offering expert perspectives on PEN's use in translational research.

[Ru(phen)2podppz]2+ significantly inhibits glioblastoma growth in vitro and vivo with fewer side-effects than cisplatin

To overcome the acquired resistance and the significant side-effects of the reported drugs, four new ruthenium(ii) complexes with alkynyl (Ru1, Ru2, Ru3, Ru4) were designed and synthesized. Ru1, Ru2, Ru3 and Ru4 were characterized by ESI-MS, 1H NMR, 1H-1H COSY NMR and elemental analysis. Compared with Ru2, Ru3, Ru4 and cisplatin, the anti-tumor experiments in vitro and vivo confirmed that Ru1 could most effectively inhibit tumor growth. In the experiments of safety evaluation in vivo, Ru1 could avoid any detectable side-effects compared with cisplatin. DNA binding experiments and cell cycle experiments showed that Ru1 exhibited the strongest DNA binding ability and interfered with the cell cycle by inserting DNA to inhibit tumor growth. The study demonstrated that Ru1 had the potential to be an exciting new drug candidate for glioblastoma treatment.

Bio-Responsive nanoparticle for tumor targeting and enhanced photo-immunotherapy

Despite the potential of immunotherapy in various solid tumors, the efficiency of immunotherapy is limited by little tumor-infiltrating lymphocytes (TILs) and abundant immunosuppressive M2-type tumor-associated macrophages (M2-TAMs) in the tumor microenvironment (TME). Herein, we design a versatile photo-immunotherapy nanoparticle (termed as HA-AuNR/M-M2pep NP) to conquer above challenges. The HA-AuNR/M-M2pep NP is composed of hyaluronic acid modified gold nanorod (HA-AuNR) surface-modified with matrix metalloproteinase-2 (MMP2)-responsive M2pep fusion peptides (M-M2pep). Upon tumor site, the fabricated HA-AuNR/M-M2pep NP releases M2pep through the cleavage of MMP2-sensitive peptide to selectively deplete M2-TAMs and improve immunoactivity of TME. Meanwhile, HA-AuNR could target to tumor cells and realize precise tumor photothermal therapy (PTT) under near infrared light irradiation, which further triggers immunogenic cell death (ICD) of tumor cells and elicits antitumor immunity. In vivo antitumor studies reveal that HA-AuNR/M-M2pep NPs-mediated PTT and M2-TAMs depletion recruit TILs, activate effector T lymphocytes, secrete antitumor cytokines (e.g. IFN-γ, TNF-α), and effectively inhibit the growth of tumor. Collectively, HA-AuNR/M-M2pep NP-mediated photo-immunotherapy based on dual targeted delivery and bio-responsive drug release holds tremendous promise to enhance antitumor efficacy.

Polydopamine-Based Nanoparticles for Photothermal Therapy/Chemotherapy and their Synergistic Therapy with Autophagy Inhibitor to Promote Antitumor Treatment

Polydopamine (PDA) has attracted much attention recently due to its strong adhesion capability to most substrates. After combining with organic (such as organic metal framework, micelles, hydrogel, polypeptide copolymer) or inorganic nanomaterials (such as gold, silicon, carbon), polydopamine-based nanoparticles (PDA NPs) exhibit the merging of characteristics. Until now, the preparation methods, polymerization mechanism, and photothermal therapy (PTT) or chemotherapy (CT) applications of PDA NPs have been reported detailly. Since the PTT or CT treatment process is often accompanied by exogenous stimuli, tumor cells usually induce pro-survival autophagy to protect the cells from further damage, which will weaken the therapeutic effect. Therefore, an in-depth understanding of PDA NPs modulated PTT, CT, and autophagy is required. However, this association is rarely reviewed. Herein, we briefly described the relationship between PTT/CT, autophagy, and tumor treatment. Then, the outstanding performances of PDA NPs in PTT/CT and their combination with autophagy inhibitors for tumor synergistic therapy have been summarized. This work is expected to shed light on the multi-strategy antitumor therapy applications of PDA NPs.

Combined cancer therapeutics-Tackling the complexity of the tumor microenvironment

Cancer treatment has yet to find a "silver bullet" capable of selectively and effectively kill tumor cells without damaging healthy cells. Nanomedicine is a promising field that can combine several moieties in one system to produce a multifaceted nanoplatform. The tumor microenvironment (TME) is considered responsible for the ineffectiveness of cancer therapeutics and the difficulty in the translation from the bench to bed side of novel nanomedicines. A promising approach is the use of combinatorial therapies targeting the TME with the use of stimuli-responsive nanomaterials which would increase tumor targeting. Contemporary combined strategies for TME-targeting nanoformulations are based on the application of external stimuli therapies, such as photothermy, hyperthermia or ultrasounds, in combination with stimuli-responsive nanoparticles containing a core, usually composed by metal oxides or graphene, and a biocompatible stimuli-responsive coating layer that could also contain tumor targeting moieties and a chemotherapeutic agent to enhance the therapeutic efficacy. The obstacles that nanotherapeutics must overcome in the TME to accomplish an effective therapeutic cargo delivery and the proposed strategies for improved nanotherapeutics will be reviewed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Supramolecular cancer nanotheranostics

Among the many challenges in medicine, the treatment and cure of cancer remains an outstanding goal given the complexity and diversity of the disease. Nanotheranostics, the integration of therapy and diagnosis in nanoformulations, is the next generation of personalized medicine to meet the challenges in precise cancer diagnosis, rational management and effective therapy, aiming to significantly increase the survival rate and improve the life quality of cancer patients. Different from most conventional platforms with unsatisfactory theranostic capabilities, supramolecular cancer nanotheranostics have unparalleled advantages in early-stage diagnosis and personal therapy, showing promising potential in clinical translations and applications. In this review, we summarize the progress of supramolecular cancer nanotheranostics and provide guidance for designing new targeted supramolecular theranostic agents. Based on extensive state-of-the-art research, our review will provide the existing and new researchers a foundation from which to advance supramolecular cancer nanotheranostics and promote translationally clinical applications.

Nanomedicine-Based Strategies Assisting Photodynamic Therapy for Hypoxic Tumors: State-of-the-Art Approaches and Emerging Trends

Since the first clinical cancer treatment in 1978, photodynamic therapy (PDT) technologies have been largely improved and approved for clinical usage in various cancers. Due to the oxygen-dependent nature, the application of PDT is still limited by hypoxia in tumor tissues. Thus, the development of effective strategies for manipulating hypoxia and improving the effectiveness of PDT is one of the most important area in PDT field. Recently, emerging nanotechnology has benefitted progress in many areas, including PDT. In this review, after briefly introducing the mechanisms of PDT and hypoxia, as well as basic knowledge about nanomedicines, we will discuss the state of the art of nanomedicine-based approaches for assisting PDT for treating hypoxic tumors, mainly based on oxygen replenishing strategies and the oxygen dependency diminishing strategies. Among these strategies, we will emphasize emerging trends about the use of nanoscale metal-organic framework (nMOF) materials and the combination of PDT with immunotherapy. We further discuss future perspectives and challenges associated with these trends in both the aspects of mechanism and clinical translation.

Recent advances in innovative strategies for enhanced cancer photodynamic therapy

Photodynamic therapy (PDT), a non-invasive therapeutic modality, has received increasing attention owing to its high selectivity and limited side effects. Although significant clinical research progress has been made in PDT, the breadth and depth of its clinical application have not been fully realized due to the limitations such as inadequate light penetration depth, non-targeting photosensitizers (PSs), and tumor hypoxia. Consequently, numerous investigations put their emphasis on innovative strategies to overcome the aforementioned limitations and enhance the therapeutic effect of PDT. Herein, up-to-date advances in these innovative methods for PDT are summarized by introducing the design of PS systems, their working mechanisms and application examples. In addition, current challenges of these innovative strategies for clinical application, and future perspectives on further improvement of PDT are also discussed.

Transporting mitochondrion-targeting photosensitizers into cancer cells by low-density lipoproteins for fluorescence-feedback photodynamic therapy

Low-density lipoproteins (LDLs) are an endogenous nanocarrier to transport lipids in vivo. Owing to their biocompatibility and biodegradability, reduced immunogenicity, and natural tumor-targeting capability, we, for the first time, report the reconstitution of native LDL particles with saturated fatty acids and a mitochondrion-targeting aggregation-induced emission (AIE) photosensitizer for fluorescence-feedback photodynamic therapy (PDT). In particular, a novel AIE photosensitizer (TPA-DPPy) with a donor-acceptor (D-A) structure and a pyridinium salt is designed and synthesized, which possesses typical AIE and twisted intramolecular charge transfer (TICT) characteristics as well as reactive oxygen species (ROS)-sensitizing capability. In view of its prominent photophysical and photochemical properties, TPA-DPPy is encapsulated into LDL particles for photodynamic killing of cancer cells that overexpress LDL receptors (LDLRs). The resultant LDL (rLDL) particles maintain a similar morphology and size distribution to native LDL particles, and are efficiently ingested by cancer cells via LDLR-mediated endocytosis, followed by the release of TPA-DPPy for mitochondrion-targeting. Upon light irradiation, the produced ROS surrounding mitochondria lead to efficient and irreversible cell apoptosis. Interestingly, this process can be fluorescently monitored in a real-time fashion, as reflected by the remarkably enhanced luminescence and blue-shifted emission, indicating the increased mechanical stress during apoptosis. Quantitative cell viability analysis suggests that TPA-DPPy exhibits an outstanding phototoxicity toward LDLR-overexpressing A549 cancer cells, with a killing efficiency of ca. 88%. The rLDL particles are a class of safe and multifunctional nanophototheranostic agents, holding great promise in high-quality PDT by providing real-time fluorescence feedback on the therapeutic outcome.

Enhancement of tumor lethality of ROS in photodynamic therapy

In the process of photodynamic therapy (PDT) treatment of tumors, reactive oxygen species (ROS) plays a key role in destroying tumor tissues. However, traditional PDT often has limited ROS killing capacity due to hypoxia in the tumor microenvironment (TME) or obstruction by the ROS defense system, resulting in poor efficacy. Therefore, enhancing the killing effect of ROS on tumors is the core of enhancing the anti-tumor effect of PDT. In recent years, many studies have developed a series of strategies to enhance the ability of ROS to kill tumors in view of the limitations of the TME on PDT. This article summarizes the commonly used or innovative strategies in recent years, including not only frequently used methods for hypoxia in the TME but also innovative strategies to inhibit the ROS defense system.

Regulating Tumor N6 -Methyladenosine Methylation Landscape using Hypoxia-Modulating OsSx Nanoparticles

The epigenetic dysregulation and hypoxia are two important factors that drive tumor malignancy, and N⁶ -methyladenosine (m⁶ A) in mRNA is involved in the regulation of gene expression. Herein, a nanocatalyst OsS_x -PEG (PEG = poly(ethylene glycol)) nanoparticles (NPs) as O₂ modulator is developed to improve tumor hypoxia. OsS_x -PEG NPs can significantly downregulate genes involved in hypoxia pathway. Interestingly, OsS_x -PEG NPs elevate RNA m⁶ A methylation levels to cause the m⁶ A-dependent mRNA degradation of the hypoxia-related genes. Moreover, OsS_x -PEG NPs can regulate the expression of RNA m⁶ A methyltransferases and demethylases. Finally, DOX@OsS_x -PEG (DOX = doxorubicin; utilized as a model drug) NPs modulate tumor hypoxia and regulate mRNA m⁶ A methylation of hypoxia-related genes in vivo. As the first report about relationship between catalytic nanomaterials and RNA modifications, the research opens a new avenue for unveiling the underlying action mechanisms of hypoxia-modulating nanomaterials and shows potential of regulating RNA modification to overcome chemoresistance.

Pt@polydopamine nanoparticles as nanozymes for enhanced photodynamic and photothermal therapy

Polydopamine nanoparticles were used to stabilize a nano-Pt catalyst to relieve tumor hypoxia for enhanced photodynamic therapy and photothermal therapy.

Recent Research on Methods to Improve Tumor Hypoxia Environment

Cancer is a major disease burden worldwide. In recent years, in addition to surgical resection, radiotherapy and chemotherapy are recognized as the most effective methods for treating solid tumors. These methods have been introduced to treat tumors of different origins and stages clinically. However, due to insufficient blood flow and oxygen (O2) supply in solid tumors, hypoxia is caused, leading to decreased sensitivity of tumor cells and poor therapeutic effects. In addition, hypoxia will also lead to resistance to most anticancer drugs, accelerate malignant progress, and increase metastasis. In solid tumors, adequate O2 supply and adequate delivery of anticancer drugs are essential to improve radiotherapy and chemotherapy sensitivity. In recent decades, the researches on relieving tumor hypoxia have attracted researchers' extensive attention and achieved good results. However, as far as we know, there is no detailed review of the researches on alleviating tumor hypoxia. Therefore, in this contribution, we hope to give an overview of the researches on methods to improve tumor hypoxia environment and summarize their effect and application in tumor therapy, to provide a methodological reference for the research and development of new antitumor agents.

First-principles calculations of anharmonic and deuteration effects on the photophysical properties of polyacenes and porphyrinoids

A new method for calculating internal conversion rate constants (k[combining low line]IC), including anharmonic effects and using the Lagrangian multiplier technique, is proposed. The deuteration effect on k[combining low line]IC is investigated for naphthalene, anthracene, free-base porphyrin (H2P) and tetraphenylporphyrin (H2TPP). The results show that anharmonic effects are important when calculating k[combining low line]IC for transitions between electronic states that are energetically separated (ΔE) by more than 20 000-25 000 cm-1. Anharmonic effects are also important when ΔE < 20 000-25 000 cm-1 and when the accepting modes are X-H stretching vibrations with a frequency larger than 2000 cm-1. The calculations show that there is mixing between the S1 and S2 states of naphthalene induced by non-adiabatic interactions. The non-adiabatic interaction matrix element between the S1 and S2 states is 250 cm-1 and 50 cm-1 for the normal and fully deuterated naphthalene structure and this difference significantly affects the estimated fluorescence quantum yield. Besides aromatic hydrocarbons H2P and H2TPP, the k[combining low line]IC rate constant is also calculated for pyrometene (PM567) and tetraoxa[8]circulene (4B) with a detailed analysis of the effect of the vibrational anharmonicity.

A bilirubin-conjugated chitosan nanotheranostics system as a platform for reactive oxygen species stimuli-responsive hepatic fibrosis therapy

The development of nanoparticles that can be used as stimuli-responsive drug carriers for the treatment of different diseases has been an emerging area of research. In this study, we designed a chitosan-bilirubin micelle (ChiBil) carrying losartan, which is responsive to intrinsic reactive oxygen species (ROS), for the treatment of hepatic fibrosis. Because bilirubin is hydrophobic in nature, its carboxyl group was conjugated to an amine group from chitosan using EDC-NHS chemistry to form an amphiphilic conjugate, ChiBil. Losartan is an angiotensin receptor blocker that reduces hepatic fibrosis, and it was used as the therapeutic payload in this study to form ChiBil-losartan micelles. The release characteristics of ChiBil-losartan were tested by ROS generation to confirm losartan release. Human hepatic stellate cell line LX2 was found to be the best in vitro model for the study. The reduction of hepatic stellate cell activation after treatment with ChiBil-losartan was analyzed based on the expression of alpha-smooth muscle actin (α-SMA) in both in vitro and in vivo studies. Advanced liver fibrosis was induced in C3H/HeN mice using a thioacetamide (TAA) via intraperitoneal injection and 10% ethanol (EtOH) in their drinking water. In addition, the hydroxyproline levels, histopathological evaluation, and mRNA quantification in the liver showed a decreased collagen content in the treated groups compared to that in the untreated control group. Macrophage infiltration studies and qPCR studies of inflammatory markers also proved the reduction of hepatic fibrosis in the treatment group. The intravenous administration of ChiBil-losartan resulted in decreased fibrosis in a TAA/EtOH-induced liver fibrosis mouse model. The in vitro and in vivo results suggest that the ROS stimuli-responsive ChiBil nanoparticles carrying losartan may be a potent therapeutic option for the treatment of hepatic fibrosis. The combined effect of losartan and bilirubin exhibited a decreased hepatic fibrosis both in vitro and in vivo.