An intelligent NIR-responsive chelate copper-based anticancer nanoplatform for synergistic tumor targeted chemo-phototherapy

Copper and Copper Complexes in Tumor Therapy

Copper (Cu), a crucial trace element in physiological processes, has garnered significant interest for its involvement in cancer progression and potential therapeutic applications. The regulation of cellular copper levels is essential for maintaining copper homeostasis, as imbalances can lead to toxicity and cell death. The development of drugs that target copper homeostasis has emerged as a promising strategy for anticancer treatment, with a particular focus on copper chelators, copper ionophores, and novel copper complexes. Recent research has also investigated the potential of copper complexes in cancer therapy.

Cuproptosis: A novel therapeutic target for overcoming cancer drug resistance

Cuproptosis is a newly identified form of cell death driven by copper. Recently, the role of copper and copper triggered cell death in the pathogenesis of cancers have attracted attentions. Cuproptosis has garnered enormous interest in cancer research communities because of its great potential for cancer therapy. Copper-based treatment exerts an inhibiting role in tumor growth and may open the door for the treatment of chemotherapy-insensitive tumors. In this review, we provide a critical analysis on copper homeostasis and the role of copper dysregulation in the development and progression of cancers. Then the core molecular mechanisms of cuproptosis and its role in cancer is discussed, followed by summarizing the current understanding of copper-based agents (copper chelators, copper ionophores, and copper complexes-based dynamic therapy) for cancer treatment. Additionally, we summarize the emerging data on copper complexes-based agents and copper ionophores to subdue tumor chemotherapy resistance in different types of cancers. We also review the small-molecule compounds and nanoparticles (NPs) that may kill cancer cells by inducing cuproptosis, which will shed new light on the development of anticancer drugs through inducing cuproptosis in the future. Finally, the important concepts and pressing questions of cuproptosis in future research that should be focused on were discussed. This review article suggests that targeting cuproptosis could be a novel antitumor therapy and treatment strategy to overcome cancer drug resistance.

Carboxymethyl β-cyclodextrin grafted hollow copper sulfide@mesoporous silica carriers for stimuli-responsive pesticide delivery

Stimuli-responsive controlled release systems have received extensive attention to improve the pesticide bioavailability and minimize environmental pollution. Herein, a multiple stimuli-responsive IMI@HCuS@mSiO₂ @ -ss-CβCD delivery system was constructed using modified carboxymethyl β-cyclodextrin (CβCD-ss-COOH) as sealing materials, hollow copper sulfide nanoparticles with amino-functionalized mesoporous silica shell (HCuS@mSiO₂-NH₂) as carriers and imidacloprid (IMI) as the model drug. The cavity structure of HCuS@mSiO₂-NH₂ would provide a large space for pesticide loading. The results revealed that HCuS@mSiO₂-ss-CβCD was approximately 230 nm in size and the loading efficiency for IMI was 25.7%, and exhibited better biosafety on bacteria and seed. HCuS carriers were also served as photothermal agent and possessed high photothermal conversion effect (η = 38.4%). IMI@HCuS@mSiO₂ @ -ss-CβCD displayed excellent foliage adhesion and multiple stimuli-responsive release properties to pH, α-amylase, GSH, and NIR. The photostability of IMI embedded in CuS@mSiO₂ @ -ss-CβCD was approximately 10 times that of IMI solution. This work provides an efficient nanoplatform for realizing pesticide delivery.

Menthol: An underestimated anticancer agent

Menthol, a widely used natural, active compound, has recently been shown to have anticancer activity. Moreover, it has been found to have a promising future in the treatment of various solid tumors. Therefore, using literature from PubMed, EMBASE, Web of Science, Ovid, ScienceDirect, and China National Knowledge Infrastructure databases, the present study reviewed the anticancer activity of menthol and the underlying mechanism. Menthol has a good safety profile and exerts its anticancer activity via multiple pathways and targets. As a result, it has gained popularity for significantly inhibiting different types of cancer cells by various mechanisms such as induction of apoptosis, cell cycle arrest, disruption of tubulin polymerization, and inhibition of tumor angiogenesis. Owing to the excellent anticancer activity menthol has demonstrated, further research is warranted for developing it as a novel anticancer agent. However, there are limitations and gaps in the current research on menthol, and its antitumor mechanism has not been completely elucidated. It is expected that more basic experimental and clinical studies focusing on menthol and its derivatives will eventually help in its clinical application as a novel anticancer agent.

Endoplasmic reticulum-targeted NIR-II phototherapy combined with inflammatory vascular suppression elicits a synergistic effect against TNBC

Recurrence and metastasis are the main reasons for failure in the treatment of triple-negative breast cancer (TNBC). Phototherapy, one of the most well-known potent cancer treatment models is highlighted by ablating primitive tumors with immunogenic cell death (ICD) and is associated with endoplasmic reticulum (ER) stress to elicit long-lasting anti-tumor immunity. However, the provoked inflammatory response after phototherapy will stimulate angiogenesis, which provides nutrition for tumor recurrence. Here, an ER-targeted nanoplatform was constructed based on hollow mesoporous Cu_2-XS (HMCu_2-XS) nanoparticles to suppress recurrence and metastasis of TNBC by combining photo-ablation and microenvironment remodeling. Profiting from the metal ion coordination and large hollow space, HMCu_2-XS can be easily modified with p-toluenesulfonamide for ER-targeting and quantitatively loaded celecoxib (CXB) as a vascular inhibitor, thus obtaining ER-HMCu_2-XS/CXB. ER-HMCu_2-XS showed great photothermal and photodynamic efficiency for ablating 4T1 tumors and inducing ICD under NIR-II laser irradiation. Compared with non-ER-targeted nanosystems, the ER-targeted nanosystem elicited stronger ICDs and recruited more immune cells. Moreover, the thermal-responsively released CXB successfully inhibited angiogenesis after photothermal therapy. The data showed that the ER-HMCu_2-XS/CXB mediated the triplicate therapeutic effect of photo-ablation, immune response activation, and vascular suppression effectively, preventing the recurrence and metastasis of TNBC. In conclusion, this work provides a synergistic strategy to enhance therapeutic outcomes in TNBC.

A combination therapy of bortezomib, CXCR4 inhibitor, and checkpoint inhibitor is effective in cholangiocarcinoma in vivo

Cholangiocarcinoma (CCA) is a biliary tree malignancy with a dismal prognosis. Tumor microenvironment (TME), including cancer-associated fibroblasts (CAFs) has been shown to be involved in drug resistance. To model the interactions between cancer cells and the TME, we established CCA complex patient-derived organoids (cPDOs) to include epithelial PDO (ePDOs) and matched CAFs. While ePDOs were sensitive to bortezomib, we found the matched cPDOs were relatively resistant. Mechanistically, this resistance was correlated with over-expression of CXCR4 in the CAF component of cPDOs. In accord with the role of CXCR4 in the resistance to bortezomib, we found that a CXCR4 inhibitor can reverse the resistance to bortezomib in vivo. Furthermore, we found that the inhibition of CXCR4 allowed bortezomib to sensitize CCA to anti-PD1 treatment, with a significant reduction of tumor burden and long-term overall survival. This novel cancer/stroma/immune triple treatment holds great promise for the treatment of CCA.

Chemodrug-gated mesoporous nanoplatform for new near-infrared light controlled drug release and synergistic chemophotothermal therapy of tumours

Controlled drug release and synergistic therapies have an important impact on improving therapeutic efficacy in cancer theranostics. Herein, a new near-infrared (NIR) light-controlled multi-functional nanoplatform (GNR@mSiO₂-DOX/PFP@PDA) was developed for synergistic chemo-photothermal therapy (PTT) of tumours. In this nano-system, doxorubicin hydrochloride (DOX) and perfluoro-n-pentane (PFP) were loaded into the channels of mesoporous SiO₂ simultaneously as a first step. A polydopamine (PDA) layer as the gatekeeper was coated on their surface to reduce premature release of drugs at physiological temperature. Upon 808 nm NIR irradiation, the gold nanorods (GNR) in the core of the nanoplatform show high photothermal conversion efficiency, which not only can provide the heat for PTT, but also can decompose the polymer PDA to allow DOX release from the channels of mesoporous SiO₂. Most importantly, the photothermal conversion of GNR can also lead the liquid-gas phase transition of PFP to generate bubbles to accelerate the release of DOX, which can realize the chemotherapy of tumours. The subsequent synergistic chemo-PTT (contributed by the DOX and GNR) shows good anti-cancer activity. This work shows that the NIR-triggered multi-functional nanoplatform is of capital significance for future potential applications in drug delivery and cancer treatment.

Chemodrug-gated mesoporous nanoplatform for new near-infrared light controlled drug release and synergistic chemophotothermal therapy of tumours

Controlled drug release and synergistic therapies have an important impact on improving therapeutic efficacy in cancer theranostics. Herein, a new near-infrared (NIR) light-controlled multi-functional nanoplatform (GNR@mSiO₂-DOX/PFP@PDA) was developed for synergistic chemo-photothermal therapy (PTT) of tumours. In this nano-system, doxorubicin hydrochloride (DOX) and perfluoro-n-pentane (PFP) were loaded into the channels of mesoporous SiO₂ simultaneously as a first step. A polydopamine (PDA) layer as the gatekeeper was coated on their surface to reduce premature release of drugs at physiological temperature. Upon 808 nm NIR irradiation, the gold nanorods (GNR) in the core of the nanoplatform show high photothermal conversion efficiency, which not only can provide the heat for PTT, but also can decompose the polymer PDA to allow DOX release from the channels of mesoporous SiO₂. Most importantly, the photothermal conversion of GNR can also lead the liquid-gas phase transition of PFP to generate bubbles to accelerate the release of DOX, which can realize the chemotherapy of tumours. The subsequent synergistic chemo-PTT (contributed by the DOX and GNR) shows good anti-cancer activity. This work shows that the NIR-triggered multi-functional nanoplatform is of capital significance for future potential applications in drug delivery and cancer treatment.

All-in-one approaches for triple-negative breast cancer therapy: metal-phenolic nanoplatform for MR imaging-guided combinational therapy

BACKGROUND

Conventional chemotherapy has poor efficacy in triple-negative breast cancer (TNBC) which is highly heterogeneous and aggressive. Imaging-guided therapy is usually combined with diverse treatment modalities, could realize the integration of diagnosis and treatments. Therefore, the primary challenge for combinational therapy is designing proper delivery systems to accomplish multiple synergistic effects.

RESULTS

Herein, a facile nanoplatform was manufactured to fulfill the all-in-one approaches for TNBC combinational therapy. Fe³⁺-based metal-phenolic networks (MPNs) with bovine serum albumin (BSA) modification served as drug delivery carriers to encapsulate bleomycin (BLM), forming BFE@BSA NPs. The self-assembly mechanism, pH-responsive drug release behavior, and other physicochemical properties of this system were characterized. The potential of BFE@BSA NPs as photothermal transduction agents and magnetic resonance imaging (MRI) contrast agents was explored. The synergistic anti-tumor effects consisting of BLM-induced chemotherapy, Fenton reactions-mediated chemodynamic therapy, and photothermal therapy-induced apoptosis were studied both in vitro and in vivo. Once internalized into tumor cells, released BLM could cause DNA damage, while Fenton reactions were initiated to produce highly toxic •OH. Upon laser irradiation, BFE@BSA NPs could convert light into heat to achieve synergistic effects. After intravenous administration, BFE@BSA NPs exhibited great therapeutic effects in 4T1 tumor xenograft model. Moreover, as T₁-weighted MRI contrast agents, BFE@BSA NPs could provide diagnosis and treatment monitoring for individualized precise therapy.

CONCLUSIONS

A nano-system that integrated imaging and combinational therapy (chemotherapy, chemodynamic therapy and photothermal therapy) were developed to kill the tumor and monitor therapeutic efficacy. This strategy provided an all-in-one theranostic nanoplatform for MRI-guided combinational therapy against TNBC.

Copper-induced tumor cell death mechanisms and antitumor theragnostic applications of copper complexes

Recent studies found that unbalanced copper homeostasis affect tumor growth, causing irreversible damage. Copper can induce multiple forms of cell death, including apoptosis and autophagy, through various mechanisms, including reactive oxygen species accumulation, proteasome inhibition, and antiangiogenesis. Hence, copper in vivo has attracted tremendous attention and is in the research spotlight in the field of tumor treatment. This review first highlights three typical forms of copper's antitumor mechanisms. Then, the development of diverse biomaterials and nanotechnology allowing copper to be fabricated into diverse structures to realize its theragnostic action is discussed. Novel copper complexes and their clinical applications are subsequently described.

In Vivo Assimilation of CuS, Iron Oxide and Iron Oxide@CuS Nanoparticles in Mice: A 6-Month Follow-Up Study

Nanoparticles (NPs) are at the leading edge of nanomedicine, and determining their biosafety remains a mandatory precondition for biomedical applications. Herein, we explore the bioassimilation of copper sulfide NPs reported as powerful photo-responsive anticancer therapeutic agents. The nanoparticles investigated present a hollow shell morphology, that can be left empty (CuS NPs) or be filled with an iron oxide flower-like core (iron oxide@CuS NPs), and are compared with the iron oxide nanoparticles only (iron oxide NPs). CuS, iron oxide@CuS and iron oxide NPs were injected in 6-week-old mice, at doses coherent with an antitumoral treatment. Cu and Fe were quantified in the liver, spleen, kidneys, and lungs over 6 months, including the control animals, thus providing endogenous Cu and Fe levels in the first months after animal birth. After intravenous NPs administration, 77.0 ± 3.9% of the mass of Cu injected, and 78.6 ± 3.8% of the mass of Fe, were detected in the liver. In the spleen, we found 3.3 ± 0.6% of the injected Cu and 3.8 ± 0.6% for the Fe. No negative impact was observed on organ weight, nor on Cu or Fe homeostasis in the long term. The mass of the two metals returned to the control values within three months, a result that was confirmed by transmission electron microscopy and histology images. This bioassimilation with no negative impact comforts the possible translation of these nanomaterials into clinical practice.

Boosting Chemodynamic Therapy via a Synergy of Hypothermal Ablation and Oxidation Resistance Reduction

Chemodynamic therapy (CDT), deemed as a cutting-edge antineoplastic therapeutic tactics, efficaciously suppresses tumors via catalytically yielding hydroxyl radicals (^•OH) in tumor regions. Nevertheless, its biomedical applications are often restricted by the limited hydrogen peroxide (H₂O₂) level and upregulated antioxidant defense. Herein, a versatile nanoreactor is elaborately designed via integrating Cu_2-xS and MnO₂ for T₁-weighted magnetic resonance (MR) imaging-guided CDT, synergistically enhanced through hypothermal ablation and oxidation resistance reduction, thereby displaying splendid antitumor efficiency as well as suppression on pulmonary metastasis. The as-synthesized Cu_2-xS@MnO₂ nanoreactors afford acid-dependent Cu-based and glutathione (GSH)-activated Mn-based catalytic properties for bimodal CDT. Owing to excellent absorbance at the second near-infrared (NIR-II) window, the Cu_2-xS furnishes hypo-photo-thermal therapy (PTT) against tumor growth and ameliorates the catalytic performance for thermal-enhanced CDT. Additionally, MnO₂ significantly downregulates GSH and glutathione peroxidase 4, which synergistically boosts CDT via promoting oxidative stress, simultaneously generating Mn²⁺ for MR contrast improvement and activatable tumor imaging. Therefore, this study proffers a new attempt centered on the collaborative strategy integrating NIR-II hypothermal PTT and synergistically enhanced CDT for tumor eradication.

Metal-Polyphenol-Network Coated Prussian Blue Nanoparticles for Synergistic Ferroptosis and Apoptosis via Triggered GPX4 Inhibition and Concurrent In Situ Bleomycin Toxification

Given that traditional anticancer therapies fail to significantly improve the prognoses of triple negative breast cancer (TNBC), new modalities with high efficiency are urgently needed. Herein, by mixing the metal-phenolic network formed by tannic acid (TA), bleomycin (BLM), and Fe³⁺ with glutathione peroxidase 4 (GPX4) inhibitor (ML210) loaded hollow mesoporous Prussian blue (HMPB) nanocubes, the HMPB/ML210@TA-BLM-Fe³⁺ (HMTBF) nanocomplex is prepared to favor the ferroptosis/apoptosis synergism in TNBC. During the intracellular degradation, Fe³⁺ /Fe²⁺ conversion mediated by TA can initiate the Fenton reaction to drastically upregulate the reactive oxygen species level in cells, subsequently induce the accumulation of lipid peroxidation, and thereby cause ferroptotic cell death; meanwhile, the released ML210 efficiently represses the activity of GPX4 to activate ferroptosis pathway. Besides, the chelation of Fe²⁺ with BLM leads to in situ BLM toxification at tumor site, then triggers an effective apoptosis to synergize with ferroptosis for tumor therapy. As a result, the superior in vivo antitumor efficacy of HMTBF is corroborated in a 4T1 tumor-bearing mice model regarding tumor growth suppression, indicating that the nanoformulations can serve as efficient ferroptosis and apoptosis inducers for use in combinatorial TNBC therapy.

Disulfiram-loaded copper sulfide nanoparticles for potential anti-glioma therapy

Disulfiram (DSF) is an effective copper (Cu²⁺)-dependent antitumor agent. In the present study, we explored use of transferrin (Tf)-modified DSF/copper sulfide (CuS) nanocomplex (Tf-DSF/CuS) for glioma therapy. Tf was used as glioma targeting motifs, DSF as an anticancer agent, and CuS as a source of Cu²⁺ ions and a photothermal agent. DSF was loaded on CuS by metal-chelation, and released from the nanocomplex under acidic condition. The Tf-DSF/CuS complex exhibited high cytotoxic effect in vitro. Notably, cytotoxic activity was correlated with pH triggered release of Cu²⁺ which initiated non-toxicity to toxicity switch of DSF. Ultrasound-targeted microbubble destruction (UTMD) technique was used for highly selective accumulation of intravenous injected Tf-DSF/CuS in the glioma orthotopic tumor as compared with the free drugs and non-targeted DSF/CuS groups. Magnetic resonance imaging and pathological examinations showed that Tf-DSF/CuS effectively suppressed tumor growth, with an inhibition ratio of ~85%. Additionally, DSF load did not compromise photothermal conversion ability of CuS nanoparticles. Efficacy of the photothermal ablation therapy of Tf-DSF/CuS was evaluated under 808 nm laser irradiation both in vitro and in vivo. These findings show that copper-sulfide based disulfiram nanoparticles are effective agents for anti-glioma therapy.

Cascade Catalytic Nanoplatform Based on "Butterfly Effect" for Enhanced Immunotherapy

The unique tumor microenvironment (TME) characteristics such as immunosuppression impeded traditional cancer treatments. In contrast, developing cascade catalytic nanoplatforms by fully making use of substances in TME for cancer therapy may deserve full credit. Herein, a cascade catalytic nanoplatform based on glucose oxidase (GOD) modified mesoporous iron oxide nanoparticles (IONP) loaded with Artemisinin (ART) is developed, which is designed as IONP-GOD@ART. GOD can catalyze the oxidization of glucose into gluconic acid and H₂ O₂ , which not only realizes tumor starvation therapy, but also provides H₂ O₂ for IONP mediated Fenton reaction. Simultaneously, mesoporous IONP releases Fe²⁺ and Fe³⁺ ions in acidic TME. On the one hand, iron ions undergo Fenton reaction to generate hydroxyl radicals for chemodynamic therapy. On the other hand, the endoperoxide bridge in ART is broken in presence of Fe²⁺ and further generates reactive oxygen species (ROS) to achieve therapeutic purpose. In this sense, IONP-GOD@ART manipulates TME characteristics and leads to "butterfly effect", which brings out a large amount of ROS for eliciting immunogenic cell death, inducing M1-TAMs polarization, and further reprogramming immunosuppressive TME for enhanced immunotherapy. By this delicate design, the cascade catalytic nanoplatform of IONP-GOD@ART realizes potent cancer immunotherapy for tumor regression and metastasis prevention.

A tunable temperature-responsive and tough platform for controlled drug delivery

A tunable temperature-responsive site-specific drug-delivery platform for tumor therapy.

Fabrication of Anisotropic Cu Ferrite-Polymer Core-Shell Nanoparticles for Photodynamic Ablation of Cervical Cancer Cells

In this work we developed methylene blue-immobilized copper-iron nanoparticles (MB-CuFe NPs) through a facile one-step hydrothermal reaction to achieve a better phototherapeutic effect. The Fe/Cu ratio of the CuFe NPs was controllable by merely changing the loading amount of iron precursor concentration. The CuFe NPs could serve as a Fenton catalyst to convert hydrogen peroxide (H2O2) into reactive oxygen species (ROS), while the superparamagnetic properties also suggest magnetic resonance imaging (MRI) potential. Furthermore, the Food and Drug Administration (FDA)-approved MB photosensitizer could strongly adsorb onto the surface of CuFe NPs to facilitate the drug delivery into cells and improve the photodynamic therapy at 660 nm via significant generation of singlet oxygen species, leading to enhanced cancer cell-damaging efficacy. An MTT (thiazolyl blue tetrazolium bromide) assay proved the low cytotoxicity of the CuFe NPs to cervical cancer cells (HeLa cells), namely above 80% at 25 ppm of the sample dose. A slight dissolution of Cu and Fe ions from the CuFe NPs in an acidic environment was obtained, providing direct evidence for CuFe NPs being degradable without the risk of long-term retention in the body. Moreover, the tremendous photo-to-thermal conversion of CuFe NPs was examined, which might be combined with photodynamic therapy (PDT) for promising development in the depletion of cancer cells after a single pulse of deep-red light irradiation at high laser power.

Biodegradable Quantum Composites for Synergistic Photothermal Therapy and Copper-Enhanced Chemotherapy

In recent times, the combination therapy has garnered enormous interest owing to its great potential in clinical research. It has been reported that disulfiram, a clinical antialcoholism drug, could be degraded to diethyldithiocarbamate (DDTC) in vivo and subsequently result in the copper-DDTC complex (Cu(DDTC)₂) toward ablating cancer cells. In addition, the ultrasmall copper sulfide nanodots (CuS NDs) have shown great potential in cancer treatment because of their excellent photothermal and photodynamic therapeutic efficiencies. Herein, by taking advantage of the interactions between CuS and DDTC, a new multifunctional nanoplatform based on DDTC-loaded CuS (CuS-DDTC) NDs is successfully fabricated, leading to the achievement of the synergistic effect of photothermal and copper enhanced chemotherapy. All experimental results verified promising synergistic therapeutic effects. Moreover, in vivo biocompatibility and metabolism experiments displayed that the CuS-DDTC NDs could be quickly excreted from the body with no apparent toxicity signs. Together, our findings indicated the superior synergistic therapeutic effect of photothermal and copper-enhanced chemotherapy, providing a promising anticancer strategy based on the CuS-DDTC NDs drug delivery system.

A pH-activated autocatalytic nanoreactor for self-boosting Fenton-like chemodynamic therapy

The emergence of hydroxyl radical (˙OH)-mediated chemodynamic therapy (CDT) by the Fenton or Fenton-like reaction holds great potential for improving anticancer efficacy. Herein, an activatable autocatalytic nanoreactor (HT@GOx-DMONs) was developed for self-boosting Fenton-like CDT via decorating Cu²⁺-based metal-organic frameworks (MOFs) on glucose oxidase (GOx)-loaded dendritic mesoporous organosilica nanoparticles (DMONs) for the first time. The obtained nanoreactor could prevent the premature leakage of Cu²⁺ and GOx in neutral physiological environments conducted by the gatekeeper of growing carboxylate MOF (HKUST-1), but the explosive release of agents was realized due to the activated degradation of external HKUST-1 in acidic condition of endo/lysosomes, which thereby endowed this nanoreactor with the performance of pH-triggered ˙OH generation driven by Cu⁺-mediated autocatalytic Fenton-like reaction. Excitingly, Cu²⁺-induced glutathione (GSH) depletion and GOx-catalyzed H₂O₂ self-sufficiency unlocked by acid dramatically enhanced ˙OH generation. As expected, the effect of self-amplified CDT based on Cu²⁺-containing HT@GOx-DMONs presented wonderful in vitro toxicity and in vivo antitumor ability without leading to significant side-effects. The resulting nanoreactor with GSH consumption and H₂O₂ self-supply activated by acid may provide a promising paradigm for on-demand CDT.

A Biomimetic Nanogenerator of Reactive Nitrogen Species Based on Battlefield Transfer Strategy for Enhanced Immunotherapy

Currently, cell membrane is always utilized for the construction of biomimetic nanoparticles. By contrast, mimicking the intracellular activity seems more meaningful. Inspired by the specific killing mechanism of deoxy-hemoglobin (Hb) dependent drug (RRx-001) in hypoxic red blood cells (RBC), this work aims to develop an inner and outer RBC-biomimetic antitumor nanoplatform that replicates both membrane surface properties and intracellularly certain therapeutic mechanisms of RRx-001 in hypoxic RBC. Herein, RRx-001 and Hb are introduced into RBC membrane camouflaged TiO₂ nanoparticles. Upon arrival at hypoxic tumor microenvironment (TME), the biomimetic nanoplatform (R@HTR) is activated and triggers a series of reactions to generate reactive nitrogen species (RNS). More importantly, the potent antitumor immunity and immunomodulatory function of RNS in TME are demonstrated. Such an idea would transfer the battlefield of RRx-001 from hypoxic RBC to hypoxic TME, enhancing its combat capability. As a proof of concept, this biomimetic nanoreactor of RNS exhibits efficient tumor regression and metastasis prevention. The battlefield transfer strategy would not only present meaningful insights for immunotherapy, but also realize substantial breakthroughs in biomimetic nanotechnology.

PPy nanoneedle based nanoplatform capable of overcoming biological barriers for synergistic chemo-photothermal therapy

The biological barriers in vivo have limited the site-specific bioavailability and impeded therapeutic efficacy. To tackle these issues, nonspherical particles with a shape effect have attracted wide attention to affect the in vivo translocation of a drug delivery system. Herein, we constructed a nanoplatform based on polypyrrole (PPy) nanoneedles by hyaluronic acid (HA) modification and doxorubicin (DOX) loading. The PPy-HA@DOX nanoneedles with high aspect ratios could enhance the extravasation through the fenestrated vasculature of tumors, transport across tumor cell membrane via an endocytosis mechanism or even penetrated the membrane directly, and ultimately enter the nucleus easily via the nuclear pore complex by passive diffusion. With the ability of overcoming biological barriers, the PPy nanoneedle based nanoplatform would deliver drugs into the organelles more effectively. Under near infrared (NIR) laser irradiation, PPy as the photothermal agent could lead to tumor cellular structure damage for photothermal therapy (PTT). Therefore, PPy-HA@DOX developed here would exploit the merits of synergistic combination of chemo-photothermal therapy, which would pave the way toward more effective nanotherapeutics.

A novel versatile yolk-shell nanosystem based on NIR-elevated drug release and GSH depletion-enhanced Fenton-like reaction for synergistic cancer therapy

In this study, a versatile doxorubicin (DOX)-loaded yolk-shell nano-particles (HMCMD) assembled with manganese dioxide (MnO₂) as the core and copper sulfide (HMCuS) as the mesoporous (∼ 6.4 nm) shell, was designed and synthesized. The resulting HMCMD possess excellent photothermal conversion efficiency. The DOX release from the yolk-shell nanoparticles could be promoted by laser irradiation, which increased the chemotherapy of DOX. Meanwhile, Mn²⁺ could be released from the HMCMD through a redox reaction between MnO₂ and abundant glutathione (GSH) in tumor cells. The released Mn²⁺ could promote the decomposition of the intracellular hydrogen peroxide (H₂O₂) by Fenton-like reaction to generate the highly toxic hydroxyl radicals (·OH), thus exhibiting the effective chemodynamic therapy (CDT). Additionally, the efficiency of Mn²⁺-mediated CDT could be effectively enhanced by NIR irradiation. Further modification of polyethylene glycol (PEG) would improve the water solubility of the HMCMD to promote the uptake by MCF-7 cells. Hence, the HMCMD with synergistic effects of chemotherapy and chemodynamic/photothermal therapy would provide an alternative strategy in antitumor research.

Future Applications of MXenes in Biotechnology, Nanomedicine, and Sensors

The past few years have seen significant developments in the chemistry and potential biological applications of 2D materials. This review focuses on recent advances in the biotechnological and biomedical applications of MXenes, which are 2D carbides, nitrides, and carbonitrides of transition metals. Nanomaterials based on MXenes can be used as therapeutics for anticancer treatment, in photothermal therapy as drug delivery platforms, or as nanodrugs without any additional modification. Furthermore, we discuss the potential use of these materials in biosensing and bioimaging, including magnetic resonance and photoacoustic imaging techniques. Finally, we present the most significant examples of the use of MXenes as efficient agents for environmental and antimicrobial treatments, as well as a brief discussion of their future prospects and challenges.

Cancer Cell Membrane-Biomimetic Nanoplatform for Enhanced Sonodynamic Therapy on Breast Cancer via Autophagy Regulation Strategy

Autophagy was considered as a double-edged sword that might cooperate, aggravate, or antagonize apoptosis. We found that the sonodynamic therapy (SDT) in low dosage induced autophagy and might function as a survival pathway for breast cancer and exhibit resistance to SDT-mediated apoptosis. In this sense, it was highly desired to enhance SDT via autophagy regulation strategy. Herein, we reported a biomimetic nanoplatform based on hollow mesoporous titanium dioxide nanoparticles (HMTNPs) by autophagy inhibitor (hydroxychloroquine sulphate, HCQ) loading and cancer cell membrane (CCM) coating. Owing to the biomimetic surface functionalization, the CCM-HMTNPs/HCQ could escape from macrophage phagocytosis, actively recognize and home in on the tumor by homologous targeting ability. Afterward, the released HCQ in response to the ultrasound stimulus was capable of blocking the autophagic flux and cutting off the nutrients supply derived from the damaged organelles, which was anticipated to abrogate the cells' resistance to SDT. Meanwhile, the vessel normalization effect of HCQ alleviated the tumor hypoxia, which was bound to enhance the oxygen-dependent HMTNPs-mediated SDT treatment. Based on the above findings, it was undoubtedly logical that CCM-HMTNPs/HCQ would sensitize breast cancer cells to SDT via autophagy regulation strategy, which held a great promise in cancer treatment.

Facile formulation of near-infrared light-triggered hollow mesoporous silica nanoparticles based on mitochondria targeting for on-demand chemo/photothermal/photodynamic therapy

The incorporation of chemo/photothermal/photodynamic therapy in subcellular organelles such as mitochondria has attracted extensive attention recently. Here, we designed mitochondria-targeted hollow mesoporous silica nanoparticles (THMSNs) loaded biocompatible phase-change material L-menthol (LM) via a facile method. Meanwhile, antitumor drug doxorubicin (DOX) and near-infrared (NIR) dye indocyanine green (ICG) approved by FDA were simultaneously encapsulated into THMSNs, denoted as THMSNs@LMDI, which showed NIR radiation triggered capacity for cancer treatment. With the mitochondria-targeted ability of triphenylphosphine, the resulting THMSNs@LMDI showed evidently improved cellular internalization and specific accumulation in mitochondria. Under NIR irradiation, the versatile ICG would be bound to simultaneously produce photodynamic and photothermal therapy. Meanwhile, in view of the solid-liquid phase transition feature of gatekeeper LM, THMSNs@LMDI provided a platform for NIR-mediated temperature-responsive DOX release. As a matter of course, these smart subcellular organelle-THMSNs could serve as an effective drug delivery platform for site-specific on-demand chemo/photothermal/photodynamic therapy of cancer.

Cascade catalytic nanoplatform for enhanced starvation and sonodynamic therapy

Background: Sonodynamic therapy (SDT) has emerged as an alternative to the traditional treatments of cancer. However, the oxygen consumption induced by SDT and glucose oxidase (GOx) mediated starvation therapy would worsen the hypoxic tumor environment, which further impeded therapeutic efficacy. Purpose: To develop a nanoplatform and investigate its anti-cancer mechanism for enhanced starvation and SDT.Methods: We constructed a cascade catalytic nanoplatform based on GOx modified the mesoporous MnO₂ NPs loaded with hematoporphyrin monomethyl ether (HMME), which were designated as GOx-MnO₂/HMME. We characterized them for their catalytic activity, and investigate the magnetic resonance imaging and anti-tumor efficiency in vitro and in vivo.Results: MnO₂ NPs with catalase-like activity could oxidize H₂O₂ under acid condition to produce O₂, which not only in turn was supplied to the glucose-depletion reaction for an efficient starvation therapy, but also enhanced the ¹O₂ generation for HMME mediated SDT effect. In addition, the released Mn²⁺ ions in the system were able to enhance the MRI signal. Both in vitro and in vivo experiments suggested the cascade catalytic-therapeutic effect between GOx, MnO₂ NPs and HMME, demonstrating the enhanced starvation and SDT.

Peptide-Drug Conjugate-Based Nanocombination Actualizes Breast Cancer Treatment by Maytansinoid and Photothermia with the Assistance of Fluorescent and Photoacoustic Images

To develop a highly efficient strategy against tumors, here, a nanocombination (PDC/P@HCuS) was designed and constructed to actualize chemo-phototherapy with the assistance of fluorescence (FL) and photoacoustic (PA) images. First, a type of organic-inorganic hybrid nanosystem (P@HCuS) was engineered by coupling the fluorescence-labeled amphiphilic fPEDC copolymer on the surface of hollow mesoporous copper sulfide nanoparticle (HCuS), in which HCuS was used as a photothermal and PA agent; fPEDC as a stabilizer, chromophore, and redox/pH-sensitive gatekeeper; and both of them as drug carriers. Then, a peptide-drug conjugate (cRGD-SMCC-DM1, PDC), as a molecular targeted maytansinoid, was loaded inside of P@HCuS to form PDC/P@HCuS. Next, the PDC/P@HCuS was investigated carefully with or without near-infrared (NIR) laser irradiation. In vitro, the nanocombination exhibited stimuli-responsive drug release, obvious cellular uptake, strong cytotoxicity to tumor cells, significant impact on cell cycle, and cytoskeleton and cellular proteomics as well as evident permeability into the tumor sphere, most of which could be boosted by NIR laser irradiation. In vivo, the nanocombinaiton exerted good FL/PA imaging features and photothermal efficiency, achieved the best antitumor efficacy in the presence of NIR laser irradiation, and showed excellent biosafety. Together, it demonstrated that the PDC/P@HCuS, representing a chemo-phototherapy based on a nanocombination associated with peptide-drug conjugate, could achieve the highly efficient antitumor effect.

Copper sulfide: An emerging adaptable nanoplatform in cancer theranostics

Copper sulfide nanoparticles (CuS NPs), emerging nanoplatforms with dual diagnostic and therapeutic applications, are being actively investigated in this era of "war on cancer" owing to their versatility and adaptability. This article discusses the pros and cons of using CuS NPs in diagnostics, therapeutics, and theranostics. The first section introduces CuS NPs and discusses the features that render them more advantageous than other established nanoplatforms in cancer management. Subsequent sections include specific in vitro and in vivo results of different studies showing the potential of CuS NPs as nanoplatforms. Methods used for visualization (photoacoustic imaging and magnetic resonance imaging) of CuS NPs and treatment (phototherapy and combinatorial therapy) have also been discussed. Furthermore, the challenges and opportunities associated with using CuS NPs have been elucidated. Further investigations on CuS NPs are required to translate it for clinical applications.

Cerasome-based gold-nanoshell encapsulating L-menthol for ultrasound contrast imaging and photothermal therapy of cancer

Various nanoformulations of perfluorocarbon have been developed thus far, to achieve ultrasound imaging of tumors and tumor-targeted therapy. However, their application has been greatly limited by their short sonographic duration and large size distribution. A novel theranostic agent was constructed based on gold nanoshell cerasome-encapsulated L-menthol (GNC-LM). Owing to the sustained and controllable generation of L-menthol bubbles under near-infrared laser irradiation, GNC-LM showed good performance in contrast enhancement of ultrasound imaging in vivo. GNC-LM could be imaged for 30 min, which is much longer than the imaging time of SonoVue (commercially used microbubbles). Moreover, photothermal therapy (PTT) based on the light-to-heat conversion of the nanosystem effectively ablated the tumor. Our study demonstrated the promising potential of the obtained GNC-LM to serve as a therapeutic nanoprobe for ultrasound contrast imaging and PTT of tumors.

External stimulus responsive inorganic nanomaterials for cancer theranostics

Cancer is a highly intelligent system of cells, that works together with the body to thrive and subsequently overwhelm the host in order for its survival. Therefore, treatment regimens should be equally competent to outsmart these cells. Unfortunately, it is not the case with current therapeutic practices, the reason why it is still one of the most deadly adversaries and an imposing challenge to healthcare practitioners and researchers alike. With rapid nanotechnological interventions in the medical arena, the amalgamation of diagnostic and therapeutic functionalities into a single platform, theranostics provides a never before experienced hope of enhancing diagnostic accuracy and therapeutic efficiency. Additionally, the ability of these nanotheranostic agents to perform their actions on-demand, i.e. can be controlled by external stimulus such as light, magnetic field, sound waves and radiation has cemented their position as next generation anti-cancer candidates. Numerous reports exist of such stimuli-responsive theranostic nanomaterials against cancer, but few have broken through to clinical trials, let alone clinical practice. This review sheds light on the pros and cons of a few such theranostic nanomaterials, especially inorganic nanomaterials which do not require any additional chemical moieties to initiate the stimulus. The review will primarily focus on preclinical and clinical trial approved theranostic agents alone, describing their success or failure in the respective stages.

Target-initiated synthesis of fluorescent copper nanoparticles for the sensitive and label-free detection of bleomycin

Fluorescent copper nanoparticles (CuNPs) have received great attention due to their distinct characteristics of facile synthesis, tunable fluorescence emission, high photostability, and biological compatibility, and they have been widely used for chemical and biological analyses. Bleomycins (BLMs) are widely used antitumor agents for the clinical treatment of various cancers. Here, we develop a sensitive and label-free fluorescence method for the quantitative detection of BLM on the basis of BLM-initiated enzymatic polymerization-mediated synthesis of fluorescent CuNPs. We design two hairpin DNAs: one (Hp1) for the recognition of BLM and the other (Hp2) for signal amplification. In the presence of BLM, it may recognize and cleave the 5'-GC-3' site of the Hp1 stem, releasing the 8-17 DNAzyme fragment. The resultant 8-17 DNAzyme fragments may bind with the loop of Hp2 to form a partial double-stranded DNA (dsDNA) duplex, initiating the cyclic cleavage of Hp2 in the presence of Zn2+-dependent DNAzymes and generating numerous new DNA fragments with the free 3'-OH terminal, which can induce the formation of a poly(thymine) (poly-T) sequence with the assistance of terminal deoxynucleotidyl transferase (TdTase). Subsequently, the ploy-T sequence may function as the template for the synthesis of CuNPs with strong fluorescence emission. This method shows good selectivity and high sensitivity with a detection limit as low as 8.1 × 10-16 M, and it exhibits good performance in serum samples. Moreover, this method has distinct advantages of simplicity and low cost, holding great potential in clinical diagnosis and biomedical research.

Near-Infrared-Light-Induced Morphology Transition of Poly(ether amine) Nanoparticles for Supersensitive Drug Release

Near-infrared (NIR)-light-controlled drug release has aroused great interest because of its advantages in spatiotemporal control. Herein, a photothermally induced morphology transition of the nanoparticles (NPs) for supersensitive drug release has been demonstrated. Doxorubicin (DOX)- and cyanine (Cy)-coloaded thermosensitive poly(ether amine) NPs (DOX&Cy@PEA81) were developed. Because of the photothermal activity of Cy upon irradiation, increase in temperature at the tumor site results, which would be used not only for photothermal therapy but also to spur the release of DOX from the NPs for tunable chemotherapy. The NIR-laser-driven DOX release was validated by a series of intracellular and in vivo experiments on animals. Meanwhile, the chemo-photothermal combinatorial therapy results in optimal cytotoxicity and tumor inhibition. This article provides a promising approach to realizing supersensitive drug release and synergistic chemo-photothermal therapy for cancer.

A tumor-mitochondria dual targeted aza-BODIPY-based nanotheranostic agent for multimodal imaging-guided phototherapy

Mitochondria targeted phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has excelled as an effective approach among other non-specific techniques for its high selectivity, non-invasiveness and low systemic toxicity.