Tumor cell-activated "Sustainable ROS Generator" with homogeneous intratumoral distribution property for improved anti-tumor therapy

Sodium copper chlorophyllin-loaded chitosan nanoparticle-based photodynamic therapy for B16 melanoma cancer cells

Melanoma is one of the most aggressive and fatal skin cancers owing to its ability to metastasize and develop resistance to chemotherapy. Photodynamic therapy (PDT) is a minimally noninvasive treatment modality comprising photosensitizers (PSs), light sources, and endogenous molecular oxygen that exert a localized cytotoxic effect on cancer cells. The current study explores the therapeutic potential of sodium copper chlorophyllin-loaded chitosan nanoparticles (CH-SCC NPs) along with handheld laser-based PDT on B16 cancer cells. A modified chlorophyll derivative identified as sodium copper chlorophyllin (SCC) is a dietary supplement that has anticancer properties. Herein, we have synthesized CH-SCC NPs using the ionic gelation method to enhance the PS's bioavailability and efficiency. Chitosan nanoparticles exhibited high biocompatibility in a normal cell line L929, zebrafish, and chick embryos, and were successfully employed to deliver the SCC to cancer cells. CH-SCC NPs showed an enhanced PDT effect that killed approximately 80%-85% of B16 cells. CH-SCC NPs in combination with a handheld portable laser source showed significant therapeutic potential against the B16 skin cancer cell line. The experimental findings further strengthen our device-repurposing strategy, which suggests that SCC nanoformulations along with handheld laser can be a suitable treatment for skin cancer even in remote areas where power source and treatment cost can be a limitation.

Dual regulation of osteosarcoma hypoxia microenvironment by a bioinspired oxygen nanogenerator for precise single-laser synergistic photodynamic/photothermal/induced antitumor immunity therapy

The hypoxic tumor microenvironment (TME) of osteosarcoma (OS) is the Achilles' heel of oxygen-dependent photodynamic therapy (PDT), and tremendous challenges are confronted to reverse the hypoxia. Herein, we proposed a "reducing expenditure of O2 and broadening sources" dual-strategy and constructed ultrasmall IrO2@BSA-ATO nanogenerators (NGs) for decreasing the O2-consumption and elevating the O2-supply simultaneously. As O2 NGs, the intrinsic catalase (CAT) activity could precisely decompose the overexpressed H2O2 to produce O2 in situ, enabling exogenous O2 infusion. Moreover, the cell respiration inhibitor atovaquone (ATO) would be at the tumor sites, effectively inhibiting cell respiration and elevating oxygen content for endogenous O2 conservation. As a result, IrO2@BSA-ATO NGs systematically increase tumor oxygenation in dual ways and significantly enhance the antitumor efficacy of PDT. Moreover, the extraordinary photothermal conversion efficiency allows the implementation of precise photothermal therapy (PTT) under photoacoustic guidance. Upon a single laser irradiation, this synergistic PDT, PTT, and the following immunosuppression regulation performance of IrO2@BSA-ATO NGs achieved a superior tumor cooperative eradicating capability both in vitro and in vivo. Taken together, this study proposes an innovative dual-strategy to address the serious hypoxia problem, and this microenvironment-regulable IrO2@BSA-ATO NGs as a multifunctional theranostics platform shows great potential for OS therapy.

Molecular Engineering of Electrosprayed Hydrogel Microspheres to Achieve Synergistic Anti-Tumor Chemo-Immunotherapy with ACEA Cargo

Molecular engineering of drug delivering platforms to provide collaborative biological effects with loaded drugs is of great medical significance. Herein, cannabinoid receptor 1 (CB1)- and reactive oxygen species (ROS)-targeting electrosprayed microspheres (MSs) are fabricated by loading with the CB1 agonist arachidonoyl 2'-chloroethylamide (ACEA) and producing ROS in a photoresponsive manner. The synergistic anti-tumor effects of ACEA and ROS released from the MSs are assessed. ACEA inhibits epidermal growth factor receptor signaling and altered tumor microenvironment (TME) by activating CB1 to induce tumor cell death. The MSs are composed of glycidyl methacrylate-conjugated xanthan gum (XGMA) and Fe3+, which form dual molecular networks based on a Fe3+-(COO-)3 network and a C═C addition reaction network. Interestingly, the Fe3+-(COO-)3 network can be disassembled instantly under the conditions of lactate sodium and ultraviolet exposure, and the disassembly is accompanied by massive ROS production, which directly injures tumor cells. Meanwhile, the transition of dual networks to a single network boosts the ACEA release. Together, the activities of the ACEA and MSs promote immunogenic tumor cell death and create a tumor-suppressive TME by increasing M1-like tumor-associated macrophages and CD8+ T cells. In summation, this study demonstrates strong prospects of improving anti-tumor effects of drug delivering platforms through molecular design.

Recent Advances in Reprogramming Strategy of Tumor Microenvironment for Rejuvenating Photosensitizers-Mediated Photodynamic Therapy

Photodynamic therapy (PDT) has recently been considered a potential tumor therapy due to its time-space specificity and non-invasive advantages. PDT can not only directly kill tumor cells by using cytotoxic reactive oxygen species but also induce an anti-tumor immune response by causing immunogenic cell death of tumor cells. Although it exhibits a promising prospect in treating tumors, there are still many problems to be solved in its practical application. Tumor hypoxia and immunosuppressive microenvironment seriously affect the efficacy of PDT. The hypoxic and immunosuppressive microenvironment is mainly due to the abnormal vascular matrix around the tumor, its abnormal metabolism, and the influence of various immunosuppressive-related cells and their expressed molecules. Thus, reprogramming the tumor microenvironment (TME) is of great significance for rejuvenating PDT. This article reviews the latest strategies for rejuvenating PDT, from regulating tumor vascular matrix, interfering with tumor cell metabolism, and reprogramming immunosuppressive related cells and factors to reverse tumor hypoxia and immunosuppressive microenvironment. These strategies provide valuable information for a better understanding of the significance of TME in PDT and also guide the development of the next-generation multifunctional nanoplatforms for PDT.

Cancer diagnosis and treatment platform based on manganese-based nanomaterials

Cancer is a leading cause of death worldwide, and the development of new diagnostic and treatment methods is crucial. Manganese-based nanomaterials (MnNMs) have emerged as a focal point in the field of cancer diagnosis and treatment due to their multifunctional properties. These nanomaterials have been extensively explored as contrast agents for various imaging technologies such as magnetic resonance imaging (MRI), photoacoustic imaging (PAI), and near-infrared fluorescence imaging (NIR-FL). The use of these nanomaterials has significantly enhanced the contrast for precise tumor detection and localization. Moreover, MnNMs have shown responsiveness to the tumor microenvironment (TME), enabling innovative approaches to cancer treatment. This review provides an overview of the latest developments of MnNMs and their potential applications in tumor diagnosis and therapy. Finally, potential challenges and prospects of MnNMs in clinical applications are discussed. We believe that this review would serve as a valuable resource for guiding further research on the application of manganese nanomaterials in cancer diagnosis and treatment, addressing the current limitations, and proposing future research directions.

Stimuli-Responsive Nanoradiosensitizers for Enhanced Cancer Radiotherapy

Radiotherapy (RT) has been a classical therapeutic method of cancer for several decades. It attracts tremendous attention for the precise and efficient treatment of local tumors with stimuli-responsive nanomaterials, which enhance RT. However, there are few systematic reviews summarizing the newly emerging stimuli-responsive mechanisms and strategies used for tumor radio-sensitization. Hence, this review provides a comprehensive overview of recently reported studies on stimuli-responsive nanomaterials for radio-sensitization. It includes four different approaches for sensitized RT, namely endogenous response, exogenous response, dual stimuli-response, and multi stimuli-response. Endogenous response involves various stimuli such as pH, hypoxia, GSH, and reactive oxygen species (ROS), and enzymes. On the other hand, exogenous response encompasses X-ray, light, and ultrasound. Dual stimuli-response combines pH/enzyme, pH/ultrasound, and ROS/light. Lastly, multi stimuli-response involves the combination of pH/ROS/GSH and X-ray/ROS/GSH. By elaborating on these responsive mechanisms and applying them to clinical RT diagnosis and treatment, these methods can enhance radiosensitive efficiency and minimize damage to surrounding normal tissues. Finally, this review discusses the additional challenges and perspectives related to stimuli-responsive nanomaterials for tumor radio-sensitization.

Synthesis of the pH-sensitive nanoparticles based on the acylhydrazone bonds conjugated doxorubicin and studies on their in vivo anti-tumor effects

The purpose of this study was to synthesize DHPD polymers through the conjugation of doxorubicin (DOX) molecules onto poly(ethylene glycol) (PEG) chains via acylhydrazone bonds, and to fabricate pH-responsive DHPD nanoparticles (NPs) for investigation of their biosecurity and in vivo anti-tumor activity. The morphology, size distribution, stability, pH-responsiveness, biosecurity, and in vivo anti-tumor effects of the DHPD NPs were evaluated. Characterization of the DHPD polymers using 1H NMR, FTIR, and Raman spectra confirmed their successful synthesis. The DHPD NPs exhibited a round morphology with an average diameter of 144.4 ± 1.7 nm and a polydispersity index (PDI) of 0.23 ± 0.02. Biosecurity studies indicated that the DHPD NPs were non-toxic to treated mice, and in vitro cell tests demonstrated their ability to be taken up by 4T1 cells. Under the acidic microenvironment of 4T1 cells, the acylhydrazone bonds were cleaved, resulting in increased DOX delivery to tumor cells and improved in vivo anti-tumor effects. Animal experiments confirmed that the DHPD NPs reduced DOX toxicity while enhancing its anti-tumor activity. Furthermore, results from the analysis of γ-interferon (INF-γ), tumor necrosis factor-α (TNF-α), epidermal growth factor (EGF), and vascular endothelial growth factor (VEGF) indicated that the DHPD NPs improved the anti-4T1 tumor effect of DOX, suggesting their potential application in the treatment of breast cancer.

Activation of autophagy by in situ Zn2+ chelation reaction for enhanced tumor chemoimmunotherapy

Chemotherapy can induce a robust T cell antitumor immune response by triggering immunogenic cell death (ICD), a process in which tumor cells convert from nonimmunogenic to immunogenic forms. However, the antitumor immune response of ICD remains limited due to the low immunogenicity of tumor cells and the immunosuppressive tumor microenvironment. Although autophagy is involved in activating tumor immunity, the synergistic role of autophagy in ICD remains elusive and challenging. Herein, we report an autophagy amplification strategy using an ion-chelation reaction to augment chemoimmunotherapy in cancer treatments based on zinc ion (Zn²⁺)-doped, disulfiram (DSF)-loaded mesoporous silica nanoparticles (DSF@Zn-DMSNs). Upon pH-sensitive biodegradation of DSF@Zn-DMSNs, Zn²⁺ and DSF are coreleased in the mildly acidic tumor microenvironment, leading to the formation of toxic Zn²⁺ chelate through an in situ chelation reaction. Consequently, this chelate not only significantly stimulates cellular apoptosis and generates damage-associated molecular patterns (DAMPs) but also activates autophagy, which mediates the amplified release of DAMPs to enhance ICD. In vivo results demonstrated that DSF@Zn-DMSNs exhibit strong therapeutic efficacy via in situ ion chelation and possess the ability to activate autophagy, thus enhancing immunotherapy by promoting the infiltration of T cells. This study provides a smart in situ chelation strategy with tumor microenvironment-responsive autophagy amplification to achieve high tumor chemoimmunotherapy efficacy and biosafety.

A Multiple Stimuli-Responsive NanoCRISPR Overcomes Tumor Redox Heterogeneity to Augment Photodynamic Therapy

Redox heterogeneity of tumor cells has become one of the key factors leading to the failure of conventional photodynamic therapy (PDT). Exploration of a distinctive therapeutic strategy addressing heterogeneous predicaments is an appealing yet highly challenging task. Herein, a multiple stimuli-responsive nanoCRISPR (Must-nano) with spatial arrangement peculiarities in nanostructure and intracellular delivery is fabricated to overcome redox heterogeneity at both genetic and phenotypic levels for tumor-specific activatable PDT. Must-nano consists of a redox-sensitive core loading CRISPR/Cas9 targeting hypoxia-inducible factors-1α (HIF-1α) and a rationally designed multiple-responsive shell anchored by chlorin e6 (Ce6). Benefiting from the perfect coordination of structure and function, Must-nano avoids enzyme/photodegradation of the CRISPR/Cas9 system and exerts prolonged circulation, precise tumor recognition, and cascade-responsive performances to surmount tumor extra/intracellular barriers. After internalization into tumor cells, Must-nano could undergo hyaluronidase-triggered self-disassembly with charge reversal and rapid endosomal escape, followed by site-specific release and spatially asynchronous delivery of Ce6 and CRISPR/Cas9 under stimulations of redox signals, which not only improves tumor vulnerability to oxidative stress by complete HIF-1α disruption but also destroys the intrinsic antioxidant mechanism through glutathione depletion, thereby homogenizing redox-heterogeneous cells into oxidative stress-sensitive cell subsets. Under laser irradiation, Must-nano eventually exhibits optimal potency to amplify oxidative damage, effectively inhibiting the growth and hypoxia survival of redox-heterogeneous tumor in vitro and in vivo. Overall, our redox homogenization tactic significantly maximizes PDT efficacy and offers a promising strategy to overcome tumor redox heterogeneity in the development of antitumor therapies.

Nanotechnology-based photo-immunotherapy: a new hope for inhibition of melanoma growth and metastasis

Melanoma is the most aggressive form of skin cancer and there is a need for the development of effective anti-melanoma therapies as it shows high metastatic ability and low response rate. In addition, it has been identified that traditional phototherapy could trigger immunogenic cell death (ICD) to activate antitumor immune response, which could not only effectively arrest primary tumor growth, but also exhibit superior effects in terms of anti-metastasis, anti-recurrence for metastatic melanoma treatment However, the limited tumor accumulation of photosensitizers/photothermal agents and immunosuppressive tumor microenvironment severely weaken the immune effects. The application of nanotechnology facilitates a higher accumulation of photosensitizers/photothermal agents at the tumor site, which can thus improve the antitumor effects of photo-immunotherapy (PIT). In this review, we summarize the basic principles of nanotechnology-based PIT and highlight novel nanotechnologies that are expected to enhance the antitumor immune response for improved therapeutic efficacy.

Precise manipulation of circadian clock using MnO2 nanocapsules to amplify photodynamic therapy for osteosarcoma

Circadian rhythm (CR) disruption contributes to tumor initiation and progression, however the pharmacological targeting of circadian regulators reversely inhibits tumor growth. Precisely controlling CR in tumor cells is urgently required to investigate the exact role of CR interruption in tumor therapy. Herein, based on KL001, a small molecule that specifically interacts with the clock gene cryptochrome (CRY) functioning at disruption of CR, we fabricated a hollow MnO2 nanocapsule carrying KL001 and photosensitizer BODIPY with the modification of alendronate (ALD) on the surface (H-MnSiO/K&B-ALD) for osteosarcoma (OS) targeting. The H-MnSiO/K&B-ALD nanoparticles reduced the CR amplitude in OS cells without affecting cell proliferation. Furthermore, nanoparticles-controlled oxygen consumption by inhibiting mitochondrial respiration via CR disruption, thus partially overcoming the hypoxia limitation for photodynamic therapy (PDT) and significantly promoting PDT efficacy. An orthotopic OS model demonstrated that KL001 significantly enhanced the inhibitory effect of H-MnSiO/K&B-ALD nanoparticles on tumor growth after laser irradiation. CR disruption and oxygen level enhancement induced by H-MnSiO/K&B-ALD nanoparticles under laser irradiation were also confirmed in vivo. This discovery first demonstrated the potential of CR controlling for tumor PDT ablation and provided a promising strategy for overcoming tumor hypoxia.

Proton pump inhibitor-enhanced nanocatalytic ferroptosis induction for stimuli-responsive dual-modal molecular imaging guided cancer radiosensitization

Although radiotherapeutic efficiency has been revealed to be positively correlated with ferroptosis, the neutral/alkaline cytoplasm pH value of tumor cells remains an intrinsic challenge for efficient Fenton/Fenton-like reaction-based ferroptosis induction. Herein, PEGylated hollow mesoporous organosilica nanotheranostics (HMON)-GOx@MnO₂ nanoparticles (HGMP NPs) were designed as a ferroptosis inducer, which could specifically release Mn²⁺ in tumor cells to activate the Fenton-like reaction for ferroptosis induction. Proton pump inhibitors (PPIs) were synchronously administered for cytoplasm pH level regulation by inhibiting V-H⁺-ATPases activity, enhancing Fenton-like reaction-based ferroptosis induction. Moreover, reactive oxygen species production was facilitated via the glucose oxidase triggered cascade catalytic reaction by utilizing intracellular β-D-glucose for H₂O₂ self-supply and generation of additional cytoplasm H⁺. The PPI enhanced ferroptosis inducing nanosystem effectively inhibited tumor growth both in vitro and in vivo for tumor-specific ferroptosis induction and radiotherapy sensitization, suggesting that PPI administration could be an efficient adjuvant to reinforce Fenton/Fenton-like reaction-based ferroptosis induction for radiosensitization. STATEMENT OF SIGNIFICANCE: The cytoplasm pH value of tumor cells is typically neutral to alkaline, which is higher than that of the Fenton/Fenton-like reaction desired acidic environments, hindering its efficiency. In this study, PEGylated hollow mesoporous organosilica nanotheranostics (HMON)-GOx@MnO₂ nanoparticles were synthesized as a ferroptosis inducer, which could specifically release Mn²⁺ via depleting glutathione and then activate the Fenton-like reaction in the tumor microenvironment. The glucose oxidase was applied for H₂O₂ self-supply and addition of cytoplasm H⁺ to further boost the Fenton-like reaction. We found that proton pump inhibitors (PPIs) increased intracellular acidification by inhibiting the activity of V-H⁺-ATPases to enhance the Fenton reaction-based ferroptosis induction, suggesting PPIs administration could be a feasible strategy to reinforce ferroptosis induction for radiosensitization.

Clustered Cobalt Nanodots Initiate Ferroptosis by Upregulating Heme Oxygenase 1 for Radiotherapy Sensitization

High cobalt (Co) levels in tumors are associated with good clinical prognosis. An anticancer regimen that increases intratumoral Co through targeted nanomaterial delivery is proposed in this study. Bovine serum albumin and cobalt dichloride are applied to prepare cobaltous oxide nanodots using a facile biomineralization strategy. After iRGD peptide conjugation, the nanodots are loaded into dendritic mesoporous silica nanoparticles, generating a biocompatible product iCoDMSN. This nanocomposite accumulates in tumors after intravenous injection by deep tissue penetration and can be used for photoacoustic imaging. Proteomics research and molecular biology experiments reveal that iCoDMSN is a potent ferroptosis inducer in cancer cells. Mechanistically, iCoDMSNs upregulate heme oxygenase 1 (HMOX1), which increases transferrin receptors and reduces solute carrier family 40 member 1 (SLC40A1), resulting in Fe²⁺ accumulation and ferroptosis initiation. Furthermore, upregulated nuclear factor erythroid 2-related factor 2 (NRF2), arising from the reduction in Kelch-like ECH-associated protein 1 (KEAP1) expression, is responsible for HMOX1 enhancement after iCoDMSN treatment. Owing to intensified ferroptosis, iCoDMSN acts as an efficient radiotherapy enhancer to eliminate cancer cells in vitro and in vivo. This study demonstrates a versatile Co-based nanomaterial that primes ferroptosis by expanding the labile iron pool in cancer cells, providing a promising tumor radiotherapy sensitizer.

Reactive oxygen species-upregulating nanomedicines towards enhanced cancer therapy

Reactive oxygen species (ROS) play a crucial role in physiological and pathological processes, emerging as a therapeutic target in cancer. Owing to the high concentration of ROS in solid tumor tissues, ROS-based treatments, such as photodynamic therapy and chemodynamic therapy, and ROS-responsive drug delivery systems have been widely explored to powerfully and specifically suppress tumors. However, their anticancer efficacy is still hampered by the heterogeneous ROS levels, and thus comprehensively upregulating the ROS levels in tumor tissues can ensure an enhanced therapeutic effect, which can further sensitize and/or synergize with other therapies to inhibit tumor growth and metastasis. Herein, we review the recently emerging drug delivery strategies and technologies for increasing the H₂O₂, ˙OH, ¹O₂, and ˙O₂^- concentrations in cancer cells, including the efficient delivery of natural enzymes, nanozymes, small molecular biological molecules, and nanoscale Fenton-reagents and semiconductors and neutralization of intracellular antioxidant substances and localized input of mechanical and electromagnetic waves (such as ultrasound, near infrared light, microwaves, and X-rays). The applications of these ROS-upregulating nanosystems in enhancing and synergizing cancer therapies including chemotherapy, chemodynamic therapy, phototherapy, and immunotherapy are surveyed. In addition, we discuss the challenges of ROS-upregulating systems and the prospects for future studies.

Mn3 O4 Nanoshell Coated Metal-Organic Frameworks with Microenvironment-Driven O2 Production and GSH Exhaustion Ability for Enhanced Chemodynamic and Photodynamic Cancer Therapies

Nanomedicine exhibits emerging potentials to deliver advanced therapeutic strategies in the fight against triple-negative breast cancer (TNBC). Nevertheless, it is still difficult to develop a precise codelivery system that integrates highly effective photosensitizers, low toxicity, and hydrophobicity. In this study, PCN-224 is selected as the carrier to enable effective cancer therapy through light-activated reactive oxygen species (ROS) formation, and the PCN-224@Mn₃ O₄ @HA is created in a simple one-step process by coating Mn₃ O₄ nanoshells on the PCN-224 template, which can then be used as an "ROS activator" to exert catalase- and glutathione peroxidase-like activities to alleviate tumor hypoxia while reducing tumor reducibility, leading to improved photodynamic therapeutic (PDT) effect of PCN-224. Meanwhile, Mn²⁺ produced cytotoxic hydroxyl radicals (∙OH) via the Fenton-like reaction, thus producing a promising spontaneous chemodynamic therapeutic (CDT) effect. Importantly, by remodeling the tumor microenvironment (TME), Mn₃ O₄ nanoshells downregulated hypoxia-inducible factor 1α expression, inhibiting tumor growth and preventing tumor revival. Thus, the developed nanoshells, via light-controlled ROS formation and multimodality imaging abilities, can effectively inhibit tumor proliferation through synergistic PDT/CDT, and prevent tumor resurgence by remodeling TME.

Switchable ROS Scavenger/Generator for MRI-Guided Anti-Inflammation and Anti-Tumor Therapy with Enhanced Therapeutic Efficacy and Reduced Side Effects

Photosensitizer in photodynamic therapy (PDT)  accumulates in both tumor and adjacent normal tissue due to low selective biodistribution, results in undesirable side effect with limited clinic application. Herein, an intelligent nanoplatform is reported that selectively acts as reactive oxygen species (ROS) scavenger in normal tissue but as ROS generator in tumor microenvironment (TME) to differentially control ROS level in tumor and surrounding normal tissue during PDT. By down-regulating the produced ROS with dampened cytokine wave in normal tissue after PDT, the nanoplatform reduces the inflammatory response of normal tissue in PDT, minimizing the side effect and tumor metastasis in PDT. Alternatively, the nanoplatform switches from ROS scavenger to generator through the glutathione (GSH) responsive degradation in TME, which effectively improves the PDT efficacy with reduced GSH level and amplified oxidative stress in tumor. Simultaneously, the released Mn ions provide real-time and in situ signal change of magnetic resonance imaging (MRI) to monitor the reversal process of catalysis activity and achieve accurate tumor diagnosis. This TME-responsive ROS scavenger/generator with activable MRI contrast may provide a new dimension for design of next-generation PDT agents with precise diagnosis, high therapeutic efficacy, and low side effect.

Hyaluronic Acid-Based Nanomaterials Applied to Cancer: Where Are We Now?

Cancer cells normally develop the ability to rewire or reprogram themselves to become resistant to treatments that were previously effective. Despite progress in understanding drug resistance, knowledge gaps remain regarding the underlying biological causes of drug resistance and the design of cancer treatments to overcome it. So, resistance acquisition remains a major problem in cancer treatment. Targeted therapeutics are considered the next generation of cancer therapy because they overcome many limitations of traditional treatments. Numerous tumor cells overexpress several receptors that have a high binding affinity for hyaluronic acid (HA), while they are poorly expressed in normal body cells. HA and its derivatives have the advantage of being biocompatible and biodegradable and may be conjugated with a variety of drugs and drug carriers for developing various formulations as anticancer therapies such as micelles, nanogels, and inorganic nanoparticles. Due to their stability in blood circulation and predictable delivery patterns, enhanced tumor-selective drug accumulation, and decreased toxicity to normal tissues, tumor-targeting nanomaterial-based drug delivery systems have been shown to represent an efficacious approach for the treatment of cancer. In this review, we aim to provide an overview of some in vitro and in vivo studies related to the potential of HA as a ligand to develop targeted nanovehicles for future biomedical applications in cancer treatment.

An Intracellular Self-Assembly-Driven Uninterrupted ROS Generator Augments 5-Aminolevulinic-Acid-Based Tumor Therapy

Free radical therapy based on 5-aminolevulinic acid (ALA, a precursor of the photosensitizer protoporphyrin IX (PpIX)) has been approved by the US Food and Drug Administration for clinical tumor treatment. However, PpIX can be quickly converted into photoinactive heme, leading to unexpectedly paused production of free radicals and severely hindering its therapeutic benefits. Here, inspired by the natural biotransformation of ALA (ALA-PpIX-heme), an uninterrupted reactive oxygen species generator (URG) that converts useless heme to peroxidase mimics via intracellular self-assembly is developed. The URG is prepared by enwrapping ALA-loaded polyamide-amine dendrimers in red blood cell membrane vesicles with a further surface modification of G-quadruplex-structured AS1411. The URGs realize "¹ O₂ -•OH" uninterrupted generation through "recycling waste" in two steps: i) PpIX generates ¹ O₂ under laser irradiation; and ii) the photoinactive metabolite heme self-assembled with AS1411 to catalyze H₂ O₂ conversion into •OH. Interestingly, the specific generation of ¹ O₂ in mitochondria and •OH in nuclei further augments the free-radical-induced damage. It is demonstrated that URG can continuously produce free radicals for 6 h postirradiation, and shows 3.3-times more than that of the nonassembly group, achieving nearly 80% regression of tumors in vivo.

Loss of Renewal of Extracellular Vesicles: Harmful Effects on Embryo Development in vitro

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Nanoparticles: From synthesis to applications and beyond

In modern-day research, nanoparticles (size < 100nm) are an indispensable tool for various applications, especially in the field of biomedicine. Although enormous efforts have been made to understand the properties and specificities of nanoparticles, many questions are still not answered and the new ones arise. In this review we summarize current trends in the nanoparticle synthesis and characterization and interpret the stability of nanoparticles in various media from aqueous solutions to biological milieu important for the in vitro and in vivo studies. To get more detailed insight into nanoparticle charging properties and interactions of nanoparticles with interfaces the theoretical models are presented. Finally, the overview of nanoparticle applications is given and the future prospects are discussed.

Targeted Polymeric Nanoparticles Based on Mangiferin for Enhanced Protection of Pancreatic β-Cells and Type 1 Diabetes Mellitus Efficacy

Mangiferin (MGF) is found in many natural plants, such as Rhizoma Anemarrhenae, and has anti-diabetes effects. However, its clinical applications and development are limited by poor solubility and low-concentration enrichment in pancreatic islets. In this paper, targeted polymeric nanoparticles were constructed for MGF delivery with the desired drug loading content (6.86 ± 0.60%), excellent blood circulation, and missile-like delivery to the pancreas. Briefly, Glucagon-like peptide 1 (GLP-1) as an active targeting agent to the pancreas was immobilized on the block copolymer polyethyleneglycol-polycaprolactone (PEG-PCL) to obtain final GLP-1-PEG-PCL amphiphiles. Spherical MGF-loaded polymeric nanoparticles were acquired from the self-assembly of the targeted GDPP nanoparticles and MGF with a homogeneous size of 158.9 ± 1.7 nm and a negative potential for a good steady state in circulation. In this drug vehicle, GLP-1 acts as the missile vanguard via the GLP-1 receptor on the surface of the pancreas for improving the accumulation and efficiency of MGF in the pancreas, the hypoglycemic effect of MGF, and the restorative effect on pancreatic islets, which were investigated. As compared to free MGF, MGF/GDPP nanoparticles appeared to be more concentrated in the pancreas, with better blood glucose and glucose tolerance, enhanced insulin levels, increased β-cell proliferation, reduced β-cell apoptosis, and islet repair in vivo. This targeted drug delivery system provided a novel strategy and hope for enhancing MGF delivery and anti-diabetes efficacy.

Current trends in smart mesoporous silica-based nanovehicles for photoactivated cancer therapy

Photoactivated therapeutic strategies (photothermal therapy and photodynamic therapy), due to the adjusted therapeutic area, time and light dosage, have prevailed for the fight against tumors. Currently, the monotherapy with limited treatment effect and undesired side effects is gradually replaced by multimodal and multifunctional nanosystems. Mesoporous silica nanoparticles (MSNs) with unique physicochemical advantages, such as huge specific surface area, controllable pore size and morphology, functionalized modification, satisfying biocompatibility and biodegradability, are considered as promising candidates for multimodal photoactivated cancer therapy. Excitingly, the innovative nanoplatforms based on the mesoporous silica nanoparticles provide more and more effective treatment strategies and display excellent antitumor potential. Given the rapid development of antitumor strategies based on MSNs, this review summarizes the current progress in MSNs-based photoactivated cancer therapy, mainly consists of (1) photothermal therapy-related theranostics; (2) photodynamic therapy-related theranostics; (3) multimodal synergistic therapy, such as chemo-photothermal-photodynamic therapy, phototherapy-immunotherapy and phototherapy-radio therapy. Based on the limited penetration of irradiation light in photoactivated therapy, the challenges faced by deep-seated tumor therapy are fully discussed, and future clinical translation of MSNs-based photoactivated cancer therapy are highlighted.

Facile preparation of nanomicelles using polymyxin E for enhanced antitumor effects

Chemotherapy is a major cancer treatment that uses antitumor drugs to kill fast-growing cancer cells. Many kinds of drug carriers have been developed to deliver and achieve controlled release of small-molecule therapeutic agents. However, many therapeutic agent carriers need complex preparation process. The natural polypeptides may serve as proper drug carriers. More specifically, polymyxin E (PE) is a kind of natural antibiotic lipopeptides. It is commonly used to treat infections caused by multidrug-resistant Gram-negative bacteria. Herein, we present a facile method to prepare DOX-loaded polymyxin E micelles (PE-DOX micelles) to enhance the therapeutic effect of anticancer drug doxorubicin (DOX). The hydrodynamic sizes and zeta potential of the prepared nanomedicine (PE-DOX micelles) were 142.0 nm and 6.47 mV, respectively. The release of DOX from PE-DOX micelles was faster at pH 5.5 than that at pH 7.4. Furthermore, PE exhibited negligible cytotoxicity to A549 cells and HeLa cells within 50 μg/mL, while PE-DOX micelles caused higher cytotoxicity than that of free DOX. Moreover, the intravenously injected PE-DOX micelles showed good biocompatibility and obvious antitumor effect after 14 days' treatment in vivo. The PE-DOX micelles have great potential to be used as anticancer agent in the future.

Multimodal obstruction of tumorigenic energy supply via bionic nanocarriers for effective tumor therapy

Sufficient energy generation based on effective transport of nutrient via abundant blood vessels in tumor tissue and subsequent oxidative metabolism in mitochondria is critical for growth, proliferation and migration of tumor. Thus the strategy to cut off this transport pathway (blood vessels) and simultaneously close the power house (mitochondria) is highly desired for tumor treatment. Herein, we fabricated a bionic nanocarrier with core-shell-corona structure to give selective and effective tumor therapy via stepwise destruction of existed tumor vessel, inhibition of tumor angiogenesis and dysfunction of tumor mitochondria. The core of this bionic nanocarrier consists of combretastatin A4 phosphate (CA4P) and vitamin K₂ (VK₂) co-loaded mesoporous silica nanoparticle (MSNs), which is in charge of the vasculature destruction and mitochondrial dysfunction after cargos release. The N-tert-butylacrylamide (TBAM) and tri-sulfated N-acetylglucosamine (TSAG) shell served as artificial affinity reagent against vascular endothelial growth factor (VEGF) for angiogenesis inhibition. As to guarantee that these actions only happened in tumor, the hyaluronic acid (HA) corona was introduced to endow the nanocarrier with tumor targeting property and stimuli-responsiveness for accurate therapy. Both in vitro and in vivo results indicated that the CA4P/VK₂-MSNs-TBAM/TSAG-HA (CVM_MGH for short) nanocarrier combined well-controllable manipulation of tumor vasculature and tumor mitochondria to effectivly cut off the tumorigenic energy supply, which performed significant inhibition of tumor growth, demonstrating the great candidate of our strategy for effective tumor therapy.

Novel amphiphilic fluorine-containing nanocarriers for oxygen self-sufficiency "AND" GSH depletion sequentially to enhance photodynamic therapy

In order to maximize the retention of the photodynamic therapy (PDT) efficacy, while avoiding the dilemma of hypoxia and high reducing substances in tumor tissue, fluoropolymers were synthesized in a simple and effective methods. Fluorous effect with good oxygen carrying capacity was endowed by the fluorine-containing section in fluoropolymers and the perfluorodecalin (PFD) together, the reaction site with GSH was provided by the disulfide bond, which enhanced PDT efficiency through the sequential "AND" logic gate design. Two kind of fluorine-containing nanocarriers (M-Ce6 and E-Ce6) were obtained by solvent evaporation or ultrasound emulsification with PFD, respectively. In vitro, both of them showed promising high ROS generation under photoirradiation. Benefiting by cavitation effects, E-Ce6 had a more significant statistical difference in cellular uptake. Furthermore, the cells incubating with E-Ce6 hardly were noticed that the hypoxia signal appeared under hypoxia, while reducing the intracellular GSH content by more than 15%. Through the sequential "AND" logic gate design, ROS production even under hypoxia and GSH conditions of E-Ce6 was also almost 1.5 times that of Ce6 under normoxia. Enhancing effect of E-Ce6 was 13.47 times and 6.85 times, while selectivity ratio reached 5.13 times and 4.81 times compared with Ce6 and M-Ce6. The two-pronged strategy showed a high potential for delivering the Ce6 to deep inside of cancer cells and killing it in the simulated tumor by PDT. These above results demonstrated the potential of E-Ce6, as oxygen self-sufficiency and GSH depletion nanocarriers for combined enhancement of photodynamic therapy.

Mn3+-rich oxide/persistent luminescence nanoparticles achieve light-free generation of singlet oxygen and hydroxyl radicals for responsive imaging and tumor treatment

X-ray excited persistent luminescence (XEPL) imaging has attracted increasing attention in biomedical imaging due to elimination of autofluorescence, high signal-to-noise ratio and repeatable activation with high penetration. However, optical imaging still suffers from limited for high spatial resolution.

Methods: Herein, we report Mn³⁺-rich manganese oxide (MnO_x)-coated chromium-doped zinc gallogermanate (ZGGO) nanoparticles (Mn-ZGGOs). Enhanced XEPL and magnetic resonance (MR) imaging were investigated by the decomposition of MnO_x shell in the environment of tumors. We also evaluated the tumor cell-killing mechanism by detection of reactive oxygen (ROS), lipid peroxidation and mitochondrial membrane potential changes in vitro. Furthermore, the in vivo biodistribution, imaging and therapy were studied by U87MG tumor-bearing mice.

Results: In the tumor region, the MnO_x shell is quickly decomposed to produce Mn³⁺ and oxygen (O₂) to directly generate singlet oxygen (¹O₂). The resulting Mn²⁺ transforms endogenous H₂O₂ into highly toxic hydroxyl radical (·OH) via a Fenton-like reaction. The Mn²⁺ ions and ZGGOs also exhibit excellent T₁-weighted magnetic resonance (MR) imaging and ultrasensitive XEPL imaging in tumors.

Conclusion: Both the responsive dual-mode imaging and simultaneous self-supplied O₂ for the production of ¹O₂ and oxygen-independent ·OH in tumors allow for more accurate diagnosis of deep tumors and more efficient inhibition of tumor growth without external activation energy.