Sequential Intercellular Delivery Nanosystem for Enhancing ROS-Induced Antitumor Therapy

Chimeric nanobody-decorated liposomes by self-assembly

Liposomes as drug vehicles have advantages, such as payload protection, tunable carrying capacity and improved biodistribution. However, due to the dysfunction of targeting moieties and payload loss during preparation, immunoliposomes have yet to be favoured in commercial manufacturing. Here we report a chemical modification-free biophysical approach for producing immunoliposomes in one step through the self-assembly of a chimeric nanobody (cNB) into liposome bilayers. cNB consists of a nanobody against human epidermal growth factor receptor 2 (HER2), a flexible peptide linker and a hydrophobic single transmembrane domain. We determined that 64% of therapeutic compounds can be encapsulated into 100-nm liposomes, and up to 2,500 cNBs can be anchored on liposomal membranes without steric hindrance under facile conditions. Subsequently, we demonstrate that drug-loaded immunoliposomes increase cytotoxicity on HER2-overexpressing cancer cell lines by 10- to 20-fold, inhibit the growth of xenograft tumours by 3.4-fold and improve survival by more than twofold.

Development of Anticancer Ferric Complex Based on Human Serum Albumin Nanoparticles That Generate Oxygen in Cells to Overcome Hypoxia-Induced Resistance in Metal Chemotherapy

To achieve the remarkable therapeutic efficacy of a ferric (Fe) complex via a reactive oxygen species (ROS) mechanism in solid tumors, a therapeutic Fe-based Schiff-base complex (Fe1) was synthesized and encapsulated in human serum albumin (HSA) nanoparticles (NPs), which generated oxygen (O2) in cancer cells in situ. The HSA-Fe1-O2 NP (HSA-Fe1-O2NP) delivery system effectively overcame hypoxia-induced resistance in metal chemotherapy, alleviated the hypoxic condition of tumor tissues, and showed excellent tumor suppression by generating excess ROS and promoting the apoptosis of SK-N-MC tumor cells. The HSA-Fe1-O2NPs not only enhanced the ability of the Fe1 complex to target tumor cells but also decreased adverse effects in vivo.

Manganese Amplifies Photoinduced ROS in Toluidine Blue Carbon Dots to Boost MRI Guided Chemo/Photodynamic Therapy

The contrast agents and tumor treatments currently used in clinical practice are far from satisfactory, due to the specificity of the tumor microenvironment (TME). Identification of diagnostic and therapeutic reagents with strong contrast and therapeutic effect remains a great challenge. Herein, a novel carbon dot nanozyme (Mn-CD) is synthesized for the first time using toluidine blue (TB) and manganese as raw materials. As expected, the enhanced magnetic resonance (MR) imaging capability of Mn-CDs is realized in response to the TME (acidity and glutathione), and r1 and r2 relaxation rates are enhanced by 224% and 249%, respectively. In addition, the photostability of Mn-CDs is also improved, and show an efficient singlet oxygen (1 O2 ) yield of 1.68. Moreover, Mn-CDs can also perform high-efficiency peroxidase (POD)-like activity and catalyze hydrogen peroxide to hydroxyl radicals, which is greatly improved under the light condition. The results both in vitro and in vivo demonstrate that the Mn-CDs are able to achieve real-time MR imaging of TME responsiveness through aggregation of the enhanced permeability and retention effect at tumor sites and facilitate light-enhanced chemodynamic and photodynamic combination therapies. This work opens a new perspective in terms of the role of carbon nanomaterials in integrated diagnosis and treatment of diseases.

Cell Death Pathway Regulation by Functional Nanomedicines for Robust Antitumor Immunity

Cancer immunotherapy has become a mainstream cancer treatment over traditional therapeutic modes. Cancer cells can undergo programmed cell death including ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis which are find to have intrinsic relationships with host antitumor immune response. However, direct use of cell death inducers or regulators may bring about severe side effects that can also be rapidly excreted and degraded with low therapeutic efficacy. Nanomaterials are able to carry them for long circulation time, high tumor accumulation and controlled release to achieve satisfactory therapeutic effect. Nowadays, a large number of studies have focused on nanomedicines-based strategies through modulating cell death modalities to potentiate antitumor immunity. Herein, immune cell types and their function are first summarized, and state-of-the-art research progresses in nanomedicines mediated cell death pathways (e.g., ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis) with immune response provocation are highlighted. Subsequently, the conclusion and outlook of potential research focus are discussed.

Organism-Generated Biological Vesicles In Situ: An Emerging Drug Delivery Strategy

Biological vesicles, containing genetic materials and proteins of the original cells, are usually used for local or systemic communications among cells. Currently, studies on biological vesicles as therapeutic strategies or drug delivery carriers mainly focus on exogenously generated biological vesicles. However, the limitations of yield and purity caused by the complex purification process still hinder their clinical transformation. Recently, it has been reported that living organisms, including cells and bacteria, can produce functional/therapeutic biological vesicles within body automatically. Therefore, using organisms to produce endogenous biological vesicles in body as drug/bio-information delivery carriers has become a potential therapeutic strategy. In this review, the current development status and application prospects of in situ organism-produced biological vesicles are introduced. The advantages and effects of this endogenous biological vesicles-based strategy in drug delivery and disease treatments are analyzed. According to the type of endogenous biological vesicles, they are divided into four categories: exosomes, platelet-derived microparticles, apoptotic bodies, and bacteria-released outer membrane vesicles. And finally, the shortcomings of current research and future development are analyzed. This review is believed to open up the application of endogenous biological vesicles in the field of biomedicine and shed light on current research.

Thermo-responsive palladium-ruthenium nanozyme synergistic photodynamic therapy for metastatic breast cancer management

Reactive oxygen species (ROS) have become an effective "weapon" for cancer therapy due to their strong oxidation and high anti-tumor activity. Photodynamic therapy (PDT) is one of the classical methods to induce reactive oxygen species. Therefore, an ultraminiature palladium ruthenium alloy (sPdRu) and Ru(II) were combined with thermally responsive phase change materials (PCMs). Polypyridyl-complex (RCE) co-encapsulation was performed to obtain thermally responsive nanoparticles (PdRu-RCE@PCMNPs) for multimodal synergistic anti-breast cancer therapy. On the one hand, the thermosensitive PCM protective layer can realize the slow release of sPdRu, and then catalyze the production of oxygen from tumor endogenous H₂O₂ to perform RCE-mediated PDT. At the same time, sPdRu further increased ROS levels through peroxidase (POD) activity. On the other hand, sPdRu has high photothermal conversion efficiency and can be effectively used for photothermal therapy and photodynamic therapy. Importantly, PdRu-RCE@PCM NPs not only can effectively inhibit primary tumor growth, but also can inhibit tumor metastasis. In addition, due to the effective accumulation of sPdRu and RCE, PdRu-RCE@PCM NPs also show excellent fluorescence and photothermal imaging capabilities of tumors, which can be used for tumor tracing and evaluation of treatment. Accordingly, PdRu-RCE@PCM NPs are useful in treating primary tumors and inhibiting tumor metastasis.

Synergistic hydroxyl radical formation, system XC- inhibition and heat shock protein crosslinking tango in ferrotherapy: A prove-of-concept study of "sword and shield" theory

Ferroptosis provide new insights into designing nanomedicines for enhanced cancer therapy; however, its antitumor efficacy is relatively low, mainly due to self-protective mechanism of cancer cells, e.g., heat shock protein (HSP) overexpression. Since HSPs can be modified/inhibited by lipid peroxidation (LPO) ending products, we construct a nanoplatform, namely MPDA@Fe₃O₄-Era, to amplify intracellular reactive oxygen species (ROS) and LPO for synergistic ferrotherapy. Upon tumor acidic microenvironment and local near-infrared stimuli, this nanoplatform releases Fe₃O₄ and reacts with intracellular hydrogen peroxide (H₂O₂) to promote Fenton reaction, and yields significant intracellular ROS (specifically hydroxyl radical, ^•OH) and LPO. In turn, LPO ending products crosslink HSPs to destroy self-preservation pathways of cancer cells to enhance anticancer effect. Meanwhile, the released erastin inhibits system X_C⁻ signal pathway to depletes glutathione. Fe₃O₄ loading further provides magnetic resonance imaging T2-weighted signal to guide anti-tumor treatment. Together, this nanoplatform not only provides ^•OH (as a “sword” to attack tumor cells), but also inhibits system X_C⁻ signal pathway and crosslinks HSP (break down the “shield” of tumor cells) to maximize synergistic ferro-therapeutic effect. MPDA@Fe₃O₄-Era plus laser irradiation possessed highly efficient tumor suppression with magnified the levels of ^•OH and inactive glutathione peroxidase 4 (GPX4), which can promote the development of precise cooperative cancer therapy.

Ferrous ions doped calcium carbonate nanoparticles potentiate chemotherapy by inducing ferroptosis

Ferroptosis is a recently identified regulated cell death pathway featured in iron prompted lipid peroxidation inside cells and found to be an effective approach to suppress tumor growth. Motived by the high efficacy of ferrous ions (Fe²⁺) in initiating intracellular lipid peroxidation via the Fenton reaction, this study herein prepares a pH-responsive Fe²⁺ delivery nanocarrier by coating calcium carbonate (CaCO₃) nanoparticles with a metal-polyphenol coordination polymer composed of gallic acid (GA) and Fe²⁺. Together with simultaneous encapsulation of succinic acid conjugated cisplatin prodrugs (Pt(IV)-SA) and Fe²⁺, the yielded nanoparticles, coined as ^PGFCaCO₃, are synthesized and exhibit uniform hollow structure. After PEGylation, the resulted ^PGFCaCO₃-PEG shows increased physiological stability and pH-dependent decomposition, drug release and catalytic capability in initiating lipid peroxidation. After being endocytosed, ^PGFCaCO₃-PEG effectively promoted intracellular generation of cytotoxic reactive oxygen species including lipid peroxide, thereby exhibited superior inhibition effect towards both murine 4T1 and CT26 cancer cells over Pt(IV)-SA and ^GFCaCO₃-PEG. As a result, treatment with systemic administration of ^PGFCaCO₃-PEG effectively suppressed 4T1 tumor growth via combined Fe²⁺ initiated ferroptosis and Pt(IV)-SA mediated chemotherapy. This work highlights that intracellular delivery of Fe²⁺ is a robust approach to enhance tumor chemotherapy by inducing ferroptosis.

Mitochondrial targeted drug delivery combined with manganese catalyzed Fenton reaction for the treatment of breast cancer

In previous studies, we found that triphenylphosphine-modified doxorubicin (TPP-DOX) can effectively kill drug-resistant tumor cells, but its effect on sensitive tumor cells is weakened. In this research, with albumin from Bovine Serum (BSA) as a carrier, TPP-DOX@MnBSA (TD@MB) nanoparticles were prepared by co-loading TPP-DOX and manganese which can realize the combination of chemotherapy and chemodynamic therapy (CDT). The uniform and stable nano-spherical nanoparticle can promote drug uptake, achieve mitochondrial-targeted drug delivery, increase intracellular reactive oxygen species (ROS) and catalyze the production of highly toxic oxidative hydroxyl radicals (OH·), further inhibiting the growth of both sensitive and drug-resistant MCF-7 cells. Besides, TD@MB can down-regulate the stemness-related proteins and the metastasis-related proteins, potentially decreasing the tumor stemness and metastasis. In vivo experiment indicated that TD@MB was able to exert desired antitumor effect, good tumor targeting and biocompatibility.

Monensin Enhanced Generation of Extracellular Vesicles as Transfersomes for Promoting Tumor Penetration of Pyropheophorbide-a from Fusogenic Liposome

The current state of antitumor nanomedicines is severely restricted by poor penetration in solid tumors. It is indicated that extracellular vesicles (EVs) secreted by tumor cells can mediate the intercellular transport of antitumor drug molecules in the tumor microenvironment. However, the inefficient generation of EVs inhibits the application of this approach. Herein, we construct an EV-mediated self-propelled liposome containing monensin as the EV secretion stimulant and photosensitizer pyropheophorbide-a (PPa) as a therapeutic agent. Monensin and PPa are first transferred to the tumor plasma membrane with the help of membrane fusogenic liposomes. By hitchhiking EVs secreted by the outer tumor cells, both drugs are layer-by-layer transferred into the deep region of a solid tumor. Particularly, monensin, serving as a sustainable booster, significantly amplifies the EV-mediated PPa penetration by stimulating EV production. Our results show that this endogenous EV-driven nanoplatform leads to deep tumor penetration and enhanced phototherapeutic efficacy.

A nanodevice with lifetime-improved singlet oxygen for enhanced photodynamic therapy

The short lifetime of singlet oxygn reduces its accumulation in the ehdoplasmic reticulum, which limited the output of photodynamic therapy. A nanodevice with functions of singlet oxygen production, storage and...

Recent Advancements in Serum Albumin-Based Nanovehicles Toward Potential Cancer Diagnosis and Therapy

Recently, drug delivery vehicles based on nanotechnology have significantly attracted the attention of researchers in the field of nanomedicine since they can achieve ideal drug release and biodistribution. Among the various organic or inorganic materials that used to prepare drug delivery vehicles for effective cancer treatment, serum albumin-based nanovehicles have been widely developed and investigated due to their prominent superiorities, including good biocompatibility, high stability, nontoxicity, non-immunogenicity, easy preparation, and functionalization, allowing them to be promising candidates for cancer diagnosis and therapy. This article reviews the recent advances on the applications of serum albumin-based nanovehicles in cancer diagnosis and therapy. We first introduce the essential information of bovine serum albumin (BSA) and human serum albumin (HSA), and discuss their drug loading strategies. We then discuss the different types of serum albumin-based nanovehicles including albumin nanoparticles, surface-functionalized albumin nanoparticles, and albumin nanocomplexes. Moreover, after briefly discussing the application of serum albumin-based nanovehicles used as the nanoprobes in cancer diagnosis, we also describe the serum albumin-based nanovehicle-assisted cancer theranostics, involving gas therapy, chemodynamic therapy (CDT), phototherapy (PTT/PDT), sonodynamic therapy (SDT), and other therapies as well as cancer imaging. Numerous studies cited in our review show that serum albumin-based nanovehicles possess a great potential in cancer diagnostic and therapeutic applications.

One-in-one individual package and delivery of CRISPR/Cas9 ribonucleoprotein using apoferritin

So far, most reported delivery of CRISPR/Cas9 is achieved by internalized or encapsulated multiple ribonucleoprotein units into only one carrier unit, with relatively large size. Here, we report a novel, small-sized, individual package of CRISPR/Cas9, via using tetralysine modified H-chian apoferritin (TL-HFn) as packaging material. In this paper, each CRISPR/Cas9 complex is proved to be successfully installed into one TL-HFn (~26 nm), and delivered into the targeting cell via TfR1-mediated endocytosis. We found that after 6 h of treatment, the CRISPR/Cas9 complex can be tracked within the nuclear of Hela cells for the purpose of gene editing of enhanced green fluorescent protein (EGFP). Moreover, TL-HFn individually packed CRISPR/Cas9 displayed higher genome editing activity compared with that of free CRISPR/Cas9 treated group both in vitro (up to 28.96%) and in vivo. Such satisfied genome editing efficiency could be attributed to the endosomal escape and pH-induced disassembly abilities given by TL-HFn after uptake into cytoplasm, which had been verified in our previous research. In all, those results prompted that TL-HFn possessed more potential for intracellular delivery of CRISPR/Cas9, with potential biocompatibility, stability and delivery efficiency.

Tumor-killing nanoreactors fueled by tumor debris can enhance radiofrequency ablation therapy and boost antitumor immune responses

Radiofrequency ablation (RFA) is clinically adopted to destruct solid tumors, but is often incapable of completely ablating large tumors and those with multiple metastatic sites. Here we develop a CaCO₃-assisted double emulsion method to encapsulate lipoxidase and hemin with poly(lactic-co-glycolic acid) (PLGA) to enhance RFA. We show the HLCaP nanoreactors (NRs) with pH-dependent catalytic capacity can continuously produce cytotoxic lipid radicals via the lipid peroxidation chain reaction using cancer cell debris as the fuel. Upon being fixed inside the residual tumors post RFA, HLCaP NRs exhibit a suppression effect on residual tumors in mice and rabbits by triggering ferroptosis. Moreover, treatment with HLCaP NRs post RFA can prime antitumor immunity to effectively suppress the growth of both residual and metastatic tumors, also in combination with immune checkpoint blockade. This work highlights that tumor-debris-fueled nanoreactors can benefit RFA by inhibiting tumor recurrence and preventing tumor metastasis.

Boosting 5-ALA-based photodynamic therapy by a liposomal nanomedicine through intracellular iron ion regulation

5-Aminolevulinic acid (5-ALA) has been approved for clinical photodynamic therapy (PDT) due to its negligible photosensitive toxicity. However, the curative effect of 5-ALA is restricted by intracellular biotransformation inactivation of 5-ALA and potential DNA repair of tumor cells. Inspired by the crucial function of iron ions in 5-ALA transformation and DNA repair, a liposomal nanomedicine (MFLs@5-ALA/DFO) with intracellular iron ion regulation property was developed for boosting the PDT of 5-ALA, which was prepared by co-encapsulating 5-ALA and DFO (deferoxamine, a special iron chelator) into the membrane fusion liposomes (MFLs). MFLs@5-ALA/DFO showed an improved pharmaceutical behavior and rapidly fused with tumor cell membrane for 5-ALA and DFO co-delivery. MFLs@5-ALA/DFO could efficiently reduce iron ion, thus blocking the biotransformation of photosensitive protoporphyrin IX (PpIX) to heme, realizing significant accumulation of photosensitivity. Meanwhile, the activity of DNA repair enzyme was also inhibited with the reduction of iron ion, resulting in the aggravated DNA damage in tumor cells. Our findings showed MFLs@5-ALA/DFO had potential to be applied for enhanced PDT of 5-ALA.

Unsaturated fatty acid-tuned assembly of photosensitizers for enhanced photodynamic therapy via lipid peroxidation

Photodynamic therapy (PDT) destroys tumor cells mainly through singlet oxygen (¹O₂) generated by light-irradiated photosensitizers (PSs). However, the fleeting half-life of ¹O₂ greatly impairs PDT efficacy. Herein, we propose an unreported unsaturated fatty acid (UFA)-assisted PS co-assembly strategy to address this problem. Three UFAs, namely, oleic acid (OA), linoleic acid (LA) and linolenic acid (LNA), are capable of co-assembling with 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) into uniform nanoparticles. Under irradiation, TAPP produces ¹O₂, which directly attacks tumor cells and simultaneously oxidizes UFAs to generate lipid hydroperoxides with sustained damage. Interestingly, the unsaturation degree of UFAs is not only related to their peroxidation rate but also has a remarkable impact on the intracellular TAPP release characteristic of the nanoparticles (NPs). The TAPP-LA NPs could release the cargo rapidly and produce the highest lipid peroxidation and reactive oxygen species levels upon irradiation. Such a unique finding sheds new light on UFA-based combination applications for enhanced photodynamic efficacy by boosting lipid peroxidation.

Biomimetic Nanoscale Erythrocyte Delivery System for Enhancing Chemotherapy via Overcoming Biological Barriers

Overcoming multiple biological barriers, including circulation time in vivo, tumor vascular endothelium, reticuloendothelial system (RES), extracellular matrix (ECM), etc., is the key to improve the therapeutic efficacy of drug delivery systems in treating tumors. Inspired by the ability of natural erythrocytes to cross multiple barriers, in this study, a biomimetic delivery system named NE@DOX-Ang2 was developed for enhancing the chemotherapy of breast cancer, which employed nano-erythrocyte (NE) encapsulating doxorubicin (DOX) and surface modification with a targeted angiopep-2 peptide (Ang2). NE@DOX-Ang2 enhanced the capacity to cross biological barriers in a three-dimensional (3D) tumor spheroid model and in vivo in mice. Compared with a conventional drug delivery system of liposomes, the half-life of NE@DOX-Ang2 increased approximately 2.5 times. Moreover, NE@DOX-Ang2 exhibited excellent tumor-targeting ability and antitumor effects in vitro and in vivo. Briefly, the prepared nano-erythrocyte drug carrier has features of favorable biocompatibility and low immunogenicity and the advantage of prolonging the half-life of drugs, which may provide a novel perspective for development of clinically available nanomedicines.

A soft anti-virulence liposome realizing the explosive release of antibiotics at an infectious site to improve antimicrobial therapy

Pore-forming toxins (PFTs), the most common virulence proteins, are promising therapeutic keys in bacterial infections. CAL02, consisting of sphingomyelin (Sm) and containing a maximum ratio of cholesterol (Ch), has been applied to sequester PFTs. However, Sm, a saturated phospholipid, leads to structural rigidity of the liposome, which does not benefit PFT combination. Therefore, in order to decrease the membrane rigidity and improve the fluidity of liposomes, we have introduced an unsaturated phospholipid, phosphatidylcholine (Pc), to the saturated Sm. In this report, a soft nanoliposome (called CSPL), composed of Ch, Sm and Pc, was artificially prepared. In order to further improve its antibacterial effect, vancomycin (Van) was loaded into the hydrophilic core of CSPL, where Van can be released radically at the infectious site through transmembrane pores formed by the PFTs in CSPL. This soft Van@CSPL nanoliposome with detoxification/drug release was able to inhibit the possibility of antibiotic resistance and could play a better role in treating severe invasive infections in mice.

H2O2-independent chemodynamic therapy initiated from magnetic iron carbide nanoparticle-assisted artemisinin synergy

Chemodynamic therapy (CDT) is a booming technology that utilizes Fenton reagents to kill tumor cells by transforming intracellular H2O2 into reactive oxygen species (ROS), but insufficient endogenous H2O2 makes it difficult to attain satisfactory antitumor results.

Limiting tumor cells comprehensively at micro and macro levels to improve the therapeutic effect of chemotherapy

Clinical data shows that antitumor treatments are often ineffective if tumor cells have metastasized. To gain an effective antitumor therapeutic effect, in this report, the tumor cell was limited to the primary site and simultaneously ablated by chemotherapy. Considering the extremely complicated process of cancer metastasis, we seek to comprehensively suppress tumor metastases at both micro and macro levels, which closely link to migration and interact with each other. At the micro level, the motility of the tumor cell was decreased via accelerating mitochondria fusion. At the macro level, the unfavorable hypoxia environment was improved. A liposome-based multifunctional nanomedicine was designed by coloading latrunculin B (LAT-B), an inhibitor of actin polymerization, and doxorubicin (DOX) into the hydrophobic bilayers and aqueous cavity, respectively. Meanwhile, an oxygen reservoir named perfluoropentane (PFP) was encapsulated into the liposome core to fulfill synergistic treatment of metastatic tumors. In this paper, we demonstrated that the metastasis of the tumor cell could be effectively inhibited by LAT-B through promoting mitochondria fusion without affecting its function, making it as an encouraging candidate for effective anti-metastasis therapy. Meanwhile, we found that the combination of LAT-B and DOX shows a synergistic effect against tumors because the combined effect of these two drugs cover the entire cell proliferation process. In a word, this report presents a potential improvement in the treatment of metastatic cancer.

Hypoxia-Inducible Factor-1: A Potential Target to Treat Acute Lung Injury

Acute lung injury (ALI) is an acute hypoxic respiratory insufficiency caused by various intra- and extrapulmonary injury factors. Presently, excessive inflammation in the lung and the apoptosis of alveolar epithelial cells are considered to be the key factors in the pathogenesis of ALI. Hypoxia-inducible factor-1 (HIF-1) is an oxygen-dependent conversion activator that is closely related to the activity of reactive oxygen species (ROS). HIF-1 has been shown to play an important role in ALI and can be used as a potential therapeutic target for ALI. This manuscript will introduce the progress of HIF-1 in ALI and explore the feasibility of applying inhibitors of HIF-1 to ALI, which brings hope for the treatment of ALI.

High UV-Vis-NIR Light-Induced Antibacterial Activity by Heterostructured TiO2-FeS2 Nanocomposites

PURPOSE

Antibiotic resistance issues associated with microbial pathogenesis are considered to be one of the most serious current threats to health. Fortunately, TiO2, a photoactive semiconductor, was proven to have antibacterial activity and is being widely utilized. However, its use is limited to the short range of absorption wavelength.

METHODS

In this work, heterostructured TiO2-FeS2 nanocomposites (NCs) were successfully prepared by a facile solution approach to enhance light-induced antibacterial activity over a broader absorption range.

RESULTS

In TiO2-FeS2 NCs, FeS2 NPs, as light harvesters, can effectively increase light absorption from the visible (Vis) to near-infrared (NIR). Results of light-induced antibacterial activities indicated that TiO2-FeS2 NCs had better antibacterial activity than that of only TiO2 nanoparticles (NPs) or only FeS2 NPs. Reactive oxygen species (ROS) measurements also showed that TiO2-FeS2 NCs produced the highest relative ROS levels. Unlike TiO2 NPs, TiO2-FeS2 NCs, under light irradiation with a 515-nm filter, could absorb light wavelengths longer than 515 nm to generate ROS. In the mechanistic study, we found that TiO2 NPs in TiO2-FeS2 NCs could absorb ultraviolet (UV) light to generate photoinduced electrons and holes for ROS generation, including ⋅O2 - and ⋅OH; FeS2 NPs efficiently harvested Vis to NIR light to generate photoinduced electrons, which then were transferred to TiO2 NPs to facilitate ROS generation.

CONCLUSION

TiO2-FeS2 NCs with superior light-induced antibacterial activity could be a promising antibacterial agent against bacterial infections.

Phospholipid membrane-decorated deep-penetrated nanocatalase relieve tumor hypoxia to enhance chemo-photodynamic therapy

Hypoxia is a serious impediment to current treatments of many malignant tumors. Catalase, an antioxidant enzyme, is capable of decomposing endogenous hydrogen peroxide (H₂O₂) into oxygen for tumor reoxygenation, but suffered from in vivo instability and limited delivery to deep interior hypoxic regions in tumor. Herein, a deep-penetrated nanocatalase-loading DiIC₁₈ (5, DiD) and soravtansine (Cat@PDS) were provided by coating catalase nanoparticles with PEGylated phospholipids membrane, stimulating the structure and function of erythrocytes to relieve tumor hypoxia for enhanced chemo-photodynamic therapy. After intravenous administration, Cat@PDS preferentially accumulated at tumor sites, flexibly penetrated into the interior regions of tumor mass and remarkably relieved the hypoxic status in tumor. Notably, the Cat@PDS + laser treatment produced striking inhibition of tumor growth and resulted in a 97.2% suppression of lung metastasis. Thus, the phospholipids membrane-coated nanocatalase system represents an encouraging nanoplatform to relieve tumor hypoxia and synergize the chemo-photodynamic cancer therapy.

In Situ Cell Membrane Fusion for Engineered Tumor Cells by Worm-like Nanocell Mimics

Cell-based therapy is a promising clinic strategy to address many unmet medical needs. However, engineering cells faces some inevitable challenges, such as limited sources of cells, cell epigenetic alterations, and short shelf life during in vitro culture. Here, the worm-like nanocell mimics are fabricated to engineer effectively the tumor cells in vivo through the synergistic combination of nongenetic membrane surface engineering and inside encapsulation using in situ cell membrane fusion. The specific targeting and deformability of nanocell mimics play a vital role in membrane fusion mechanisms. The engineered primary tumor cells improved the tumor penetration of therapeutic cargoes via extracellular vesicles, while the engineered circulating tumor cells (CTCs) can capture the homologous cells to form the CTC clusters in the bloodstream and eliminate the CTC clusters in the lung, thus achieving excellent antitumor and antimetastasis efficacy. Above all, we find an intriguing phenomenon, in situ cell membrane fusion by the worm-like nanocell mimics, and our finding of in situ cell membrane fusion inspired us to engineer tumor cells in vivo. The present study would be a particularly meaningful strategy to directly engineer cells in vivo for cell-based therapy.

Mild Acid-Responsive "Nanoenzyme Capsule" Remodeling of the Tumor Microenvironment to Increase Tumor Penetration

Dense extracellular matrix (ECM) severely impedes the spread of drugs in solid tumors and induces hypoxia, reducing chemotherapy efficiency. Different proteolytic enzymes, such as collagenase (Col) or bromelain, can directly attach to the surface of nanoparticles and improve their diffusion, but the method of ligation may also impair the enzymatic activity due to conformational changes or blockage of the active site. Herein, a "nanoenzyme capsule" was constructed by combining collagenase nanocapsules (Col-nc) with heavy-chain ferritin (HFn) nanocages encapsulating the chemotherapy drug doxorubicin (DOX) to enhance tumor penetration of the nanoparticles by hydrolyzing collagen from the ECM. Col-nc could protect the activity of the enzyme before reaching the site of action while being degraded under mildly acidic conditions in tumors, and the released proteolytic enzyme could digest collagen. In addition, HFn as a carrier could effectively load DOX and had a self-targeting ability, enabling the nanoparticles to internalize into cancer cells more effectively. From in vivo and in vitro studies, we found that collagen was effectively degraded by Col-nc/HFn(DOX) to increase the accumulation and penetration of nanoparticles in the solid tumor site and could alleviate hypoxia inside the tumor to enhance the antitumor effects of DOX. Therefore, the strategy of increasing nanoparticle penetration in this system is expected to provide a potential approach for the clinical treatment of solid tumors.

Cancer Stem Cells and Combination Therapies to Eradicate Them

Cancer stem cells (CSCs) show self-renewal ability and multipotential differentiation, like normal stem or progenitor cells, and which proliferate uncontrollably and can escape the effects of drugs and phagocytosis by immune cells. Traditional monotherapies, such as surgical resection, radiotherapy and chemotherapy, cannot eradicate CSCs, however, combination therapy may be more effective at eliminating CSCs. The present review summarizes the characteristics of CSCs and several promising combination therapies to eradicate them.

A RBC membrane-camouflaged biomimetic nanoplatform for enhanced chemo-photothermal therapy of cervical cancer

Due to the untargeted release of chemical drugs, the efficacy of chemotherapy is often compromised along with serious side effects on patients. Recently, the development of targeted delivery systems using nanomaterials as carriers has provided more alternatives for chemical drug transportation. In this study, we developed a novel targeted nanocomplex of GOQD-ICG-DOX@RBCM-FA NPs (GID@RF NPs). First, PEG modified graphene oxide quantum dots (GOQDs) were used to co-load the photosensitizer of indocyanine green (ICG) and DOX, to form GOQD-ICG-DOX NPs (GID NPs). Then, the red blood cell membrane (RBCM) was applied for GID NP camouflage to avoid immune clearance. Finally, folic acid was used to endow the targeting ability of GID@RF NPs. MTT assay showed that the survival rate of HeLa cells reduced by 71% after treatment with GID@RF NPs and laser irradiation. Meanwhile, membrane camouflage significantly prolonged the blood circulation time and enhanced the immune evading ability of GID NPs. Moreover, the drug accumulation at tumor sites was significantly improved through the strong interaction between FA and FA receptor highly expressed on the tumor cells. In vivo assay demonstrated the strongest tumor growth inhibition ability of the combinational chemo/photothermal therapy. H&E analysis indicated no significant abnormalities in the major organs of mice undergoing GID@RF NPs treatment. The level of blood and biochemical parameters remained stable as compared to the control. In summary, this combinational therapy system provides a safe, rapid and effective alternative for the treatment of cervical cancer in the future.

FeS@BSA Nanoclusters to Enable H2S-Amplified ROS-Based Therapy with MRI Guidance

Therapeutic systems to induce reactive oxygen species (ROS) have received tremendous success in the research of tumor theranostics, but suffered daunting challenges in limited efficacy originating from low presence of reactants and reaction kinetics within cancer cells. Here, ferrous sulfide-embedded bovine serum albumin (FeS@BSA) nanoclusters, in an amorphous nature, are designed and synthesized via a self-assembly approach. In acidic conditions, the nanoclusters degrade and simultaneously release H2S gas and Fe2+ ions. The in vitro study using Huh7 cancer cells reveals that Fe2+ released from FeS@BSA nanoclusters induces the toxic hydroxyl radical (·OH) effectively via the Fenton reaction. More interestingly, H2S gas released intracellularly presents the specific suppression effect to catalase activity of cancer cells, resulting in the promoted presence of H2O2 that facilitates the Fenton reaction of Fe2+ and consequently promotes ROS induction within the cells remarkably. After intravenous administration, the nanoclusters accumulate in the tumors of mice via the enhanced permeability and retention effect and present strong magnetic resonance imaging (MRI) signals. The findings confirm this therapeutic system can enable superior anti-tumor performance with MRI guidance and negligible side effects. This study, therefore, offers an alternative gas-amplified ROS-based therapeutic platform for synergetic tumor treatment.

Biomimetic Aerobic Epoxidation of Alkenes Catalyzed by Cobalt Porphyrin under Ambient Conditions in the Presence of Sunflower Seeds Oil as a Co-Substrate

In this work, a mild and sustainable catalytic aerobic epoxidation of alkenes catalyzed by cobalt porphyrin was performed in the presence of sunflower seeds oil. Under ambient conditions, the conversion rate of trans-stilbene reached 99%, and selectivity toward epoxide formation was 88%. The kinetic studies showed that the aerobic epoxidation followed the Michaelis-Menten kinetics. Mass spectroscopy and in situ electron spin resonance indicated that linoleic acid was converted to fatty aldehydes via hydroperoxide intermediates. A plausible mechanism of epoxidation of alkenes was accordingly proposed.

Ovalbumin-modified nanoparticles increase the tumor accumulation by a tumor microenvironment-mediated “giant”

We designed a pH intelligently driven self-assembled nano-platform (GOx@ZIF-OVA).

Dancing with reactive oxygen species generation and elimination in nanotheranostics for disease treatment

Reactive oxygen species (ROS) play important roles in cell signaling and tissue homeostasis, in which the level of ROS is critical through the equilibrium between ROS generating and eliminating events. A disruption of the balance leads to disease development either by a surplus or a dearth of ROS, which requires ROS-modulating strategies to overturn the defect for disease treatment. Over the past decade, there have been tremendous advances in nanomedicine centering ROS generation and/or elimination as major mechanisms to treat a variety of diseases. In this review, we will discuss the research achievements on two opposite approaches of ROS-generating and ROS-eliminating strategies for treating cancer and other related diseases. Importantly, we will highlight the conceptual and strategic advances of ROS-mediated immunomodulation, including macrophage polarization, immunogenic cell death and T cell activation, which are currently rising as one of the mainstreams of cancer therapy. At the end, the future challenges and opportunities of mediating ROS-based mechanisms are envisioned. In light of the pleiotropic roles of ROS in different diseases, we hope this review is timely to deliver a clear logic of designing principles on ROS generation and elimination for different disease treatments.

ROS-Mediated Apoptosis and Anticancer Effect Achieved by Artesunate and Auxiliary Fe(II) Released from Ferriferous Oxide-Containing Recombinant Apoferritin

Reactive oxygen species (ROS)-mediated apoptosis is considered a crucial therapeutic mechanisms for artesunate (AS). As an Fe(II)-dependent drug, the anticancer effect of AS is often limited due to insufficient Fe(II) concentration in targeted cells. To overcome this problem, a recombinant apoferritin nanocarrier containing ferriferous oxide (M-HFn) is constructed to produce auxiliary exogenous Fe(II) when delivering AS to cancer cells. Here, the newly fabricated AS-loaded M-HFn nanoparticles (M-HFn@AS NPs) can significantly improve the tumor-specific targeting and intracellular uptake efficiency of AS in human cervical carcinoma cells. After being captured in the acidic cavity of endosomes, M-HFn@AS NPs can simultaneously release Fe(II) and allow AS to activate satisfactory ROS-mediated apoptosis. Furthermore, in vivo studies demonstrate that M-HFn@AS NPs can selectively accumulate in tumors to efficiently inhibit tumor growth. Thus, M-HFn@AS NPs are a promising system to enhance the therapeutic effect of Fe(II)-dependent drugs.

Manganese-Based Nanoplatform As Metal Ion-Enhanced ROS Generator for Combined Chemodynamic/Photodynamic Therapy

Reactive oxygen species (ROS) with strong oxidizing and high activity have been regarded as an effective "weapon" for antitumor therapy, since it can induce organelle injury, oxidative damage, and cell death. Herein, hollow structured manganese carbonate (MnCO₃) nanocubes are fabricated and loaded with photosensitizer (chlorin e6, Ce6), obtaining a responsive nanoplatform H-MnCO₃/Ce6-PEG (HMCP NCs). Two different approaches to upregulate intracellular ROS level were realized by HMCP NCs. On one hand, with irradiation of external laser, Ce6 could generate singlet oxygen (¹O₂) through a multistep photochemical process applied in photodynamic therapy (PDT). On the other hand, MnCO₃ could be specifically degraded into Mn²⁺ in an acidic tumor microenvironment (TME), triggering Mn²⁺-activated Fenton-like reaction to convert endogenous H₂O₂ into hydroxyl radical (•OH). In vitro combined chemodynamic therapy (CDT) and PDT showed that the metal ion-enhanced ROS production could break the intracellular redox equilibrium, thus leading to cell death. In vivo combined CDT/PDT with HMCP NCs exhibited remarkably enhanced therapeutic efficacy in inhibiting tumor growth, without resulting in noticeable damage to normal tissues. This work presents a unique type of manganese-based nanoplatform for efficiently generating ROS in solid tumors, favorable for ROS-involved therapeutic strategies.