L-Arginine self-delivery supramolecular nanodrug for NO gas therapy

NO-producing Arg-sCNDs for combined photothermal and gas effects in cancer cell ablation

Photothermal therapy (PTT) and gas therapy (GT) were used in combination to enhance the antitumor effect by leveraging the dual cytotoxic mechanisms of nitric oxide (NO) and peroxynitrite (ONOO-), along with the localized heating capability of photothermal materials. Arginine-supra-carbon nanodots (Arg-sCNDs) were obtained through a one-pot hydrothermal method without subsequent modification, allowing them to produce endogenous NO and photothermal effects on a single platform. The photothermal conversion efficiency of Arg-sCNDs reaches 77.09% and 58.01% under 730 nm and 808 nm irradiation, respectively. Arg-sCNDs demonstrated good killing and ablation effects on cancer cells and had minimal side effects on normal cells. The photothermal and NO effects reinforce each other. The cell apoptosis mechanism was demonstrated through measurements of cell temperature, NO levels, ONOO- levels, and mitochondrial membrane potential. Therefore, the in vitro study demonstrated that Arg-sCNDs with dual functions present broad application prospects in tumor cell ablation.

Near-Infrared Light-Controlled Nitric Oxide Delivery Combined with In Situ Activated Chemotherapy for Enhanced Multimodal Therapy

Development of nanoplatforms with in situ activation for chemotherapy represents a promising modality for biomedical application. Herein, a multifunctional nanoplatform, CMS@DTC@PDA@RuNO@FA (abbreviated as CDPNF NPs), was developed for highly efficient antitumor therapy, in which diethyldithiocarbamate (DTC)-loaded mesoporous Cu2MoS4 (CMS) nanoparticles were covered by polydopamine (PDA) layers and further covalently modified with a NO donor (RuNO) and a folic acid (FA)-directing moiety. Under the mild acidic tumor microenvironment (TME), the CDPNF NPs co-liberated DTC and Cu2+ in the tumor site, where in situ formation of the highly cytotoxic Cu(DTC)2 complex effectively killed tumor cells. Furthermore, under near-infrared (NIR) light irradiation, the CDPNF NPs could deliver nitric oxide (NO) and produce superoxide anions (O2•-), followed by the formation of more toxic peroxynitrite (ONOO-), which led to promoted cell apoptosis. Under 1064 nm NIR light irradiation, in vivo experiments with CDPNF NPs demonstrated an impressively high tumor inhibition rate (∼97%) while with good biocompatibility. This work represents an in situ activated approach for precision medicine that might imply its promising potential for clinical applications.

Nanoencapsulated Optical Fiber-Based PEC Microelectrode: Highly Sensitive and Specific Detection of NT-proBNP and Its Implantable Performance

Microelectrodes offer exceptional sensitivity, rapid response, and versatility, making them ideal for real-time detection and monitoring applications. Photoelectrochemical (PEC) sensors have shown great value in many fields due to their high sensitivity, fast response, and ease of operation. Nevertheless, conventional PEC sensing relies on cumbersome external light sources and bulky electrodes, hindering its miniaturization and implantation, thereby limiting its application in real-time disease monitoring. To overcome these limitations, we developed a nanoencapsulated optical fiber (OF)-based PEC microelectrode. The microelectrode features TiO2/CdS nanocrystals and bis (2,2'-bipyridine) (10-methylphenanthroline [3,2-a:2'3'-c] pyridine ruthenium(II) dichloride ([Ru(bpy)2dppz]2+) @dsDNA/Au@epigallocatechin gallate nanoparticle (EGCG NP) layers. And its application for the detection of N-terminal pro-brain natriuretic peptide (NT-proBNP) as a biomarker of cardiovascular diseases was explored. An extensive linear range of 1-5000 pg mL-1 combined with a low detection limit of 0.36 pg mL-1 was achieved. This range covers not only the recommended threshold for excluding cardiovascular diseases in the clinical diagnosis of individuals across all age groups but also the prognostic target value. The sensor exhibited excellent selectivity and stability and notable labeling recovery capability in serum tests. Critically, the sensor successfully discriminated the alterations in NT-proBNP secretion levels within human smooth muscle cells, comparing pre- and poststimulation by platelet-derived growth factor-BB. Even more significantly, the skin puncture experiment conducted in mice demonstrated the remarkable implantability and biological compatibility of the OF-PEC microelectrode. This addresses critical challenges commonly faced by microelectrodes when used as implanted devices, such as minimizing invasive trauma, mitigating inflammation, and preventing biofouling, thereby firmly establishing their suitability for the development of advanced implantable sensing devices. Therefore, the present OF microelectrode PEC biosensor is not only cost-effective, easy to operate, and miniaturized but also holds significant potential for enabling more precise, more minimally invasive, and continuous monitoring of biological markers without causing inflammation. This capability is crucial for early disease detection, tracking disease progression, and facilitating personalized treatment strategies, which expands the practical application of PEC sensors.

Hyperglycemia-responsive nitric oxide-releasing biohybrid cryogels with cascade enzyme catalysis for enhanced healing of infected diabetic wounds

Diabetic wound infections are a frequent complication for diabetic patients, and conventional treatment for combating diabetic wound infections relies on antibiotics. However, the misuse and overuse of antibiotics have led to the emergence of drug-resistant bacteria, making these infections challenging to treat. Thus, there is an urgent need for alternative strategies to effectively manage diabetic wound infections. Herein, we have developed a hyperglycemia-responsive antibacterial cryogel system that can generate and release hydrogen peroxide (H2O2) and nitric oxide (NO). This system involves incorporating glucose oxidase (GO) and L-Arginine (L-Arg: A) into hyaluronic acid aldehyde methacryloyl (HAAMA: H) and gelatin methacryloyl (GelMA: G) hybrid cryogels (GOA@HG). HAAMA facilitated higher loading and longer stability of L-Arg and GO via a Schiff base reaction. In vitro studies demonstrate that GOA@HG cryogels exhibited outstanding breathability, effective exudate management, and excellent hemostasis capabilities. Moreover, this system could consume excess glucose in diabetic wounds and efficiently eliminate bacteria through the cascaded release of H2O2 and NO without causing antibiotic resistance. In vivo studies further reveal that GOA@HG cryogels significantly enhanced the healing of infected diabetic wounds by inhibiting bacterial growth, accelerating blood vessel formation, and promoting collagen deposition. Overall, GOA@HG cryogels displayed remarkable wound dressing properties and synergistic antimicrobial effects owing to glucose-responsive H2O2 and NO release, which could serve as a highly efficient therapeutic strategy for treating infected diabetic wounds.

Versatile carrier-free binary nanodrug based on metformin/epigallocatechin gallate nanoparticles: exploring its properties and potential in cancer treatment

Epigallocatechin gallate (EGCG), an important active component extracted from green tea, has attracted much attention due to its multiple biological activities such as antioxidant, antibacterial, anti-inflammatory, and antitumor effects. Meanwhile, metformin (Met), a classic drug for the treatment of type 2 diabetes, exhibits additional benefits such as hypoglycemic, antioxidant, anti-inflammatory, and antitumor effects. However, metformin often causes gastrointestinal reactions when used alone, affecting patients' quality of life. In view of this, we proposed an innovative technique for the fabrication of a carrier-free, dual-loaded nanodrug, Met-EGCG nanoparticles (Met-EGCG NPs), via self-assembly. The method for preparing Met-EGCG NPs is simple, rapid and cost-effective. In addition, the carrier-free Met-EGCG NPs nanodrug inherits the strong antioxidant capacity, good biocompatibility and excellent aggregation-induced fluorescence effect of EGCG, and even offer significant advantages in enhancing drug solubility, stability, and bioavailability, while effectively reducing the occurrence of side effects. Moreover, this Met-EGCG NPs nanodrug exhibits a synergistic therapeutic effect of EGCG and metformin, thereby significantly enhancing overall therapeutic efficacy, and demonstrates excellent potential in anti-cancer applications. This study not only successfully prepared Met-EGCG NPs but also experimentally verified their superior performance, opening a new path for the application of EGCG in drug therapy. This carrier-free, dual-loaded drug delivery nanosystem based on Met-EGCG NPs offers potential for drug combination therapy, promising to play a more critical role in the biomedical field and providing new insights and guidance for the development of future multidrug delivery systems.

Co-delivery of vitamin and amino acid within MOFs for oxidative stress-based tumor gas therapy

As an alternative to chemotherapy, emerging gas therapy is considered a "green" treatment due to its minimal side effects. However, even typical gas molecules like nitric oxide (NO) face challenges such as a very short half-life (1.5-6 min), poor targeting, and limited therapeutic effects. This study employs a one-pot method to simultaneously encapsulate the NO donor L-arginine (L-Arg) and the H2O2 precursor Vitamin K3 (VK3) into the pores of zeolitic imidazolate framework-8 (ZIF-8), achieving their co-delivery to tumor sites to address these issues. Furthermore, ZIF-8 is functionalized with hyaluronic acid (HA) to impart active targeting properties to tumor tissues. In the acidic tumor microenvironment, pH-sensitive ZIF-8 degrades, releasing VK3 and L-Arg. Under the action of the NAD(P)H quinone oxidoreductase-1 (NQO1) enzyme, VK3 generates H2O2, increasing oxidative stress levels in the tumor microenvironment, and reacts with L-Arg to produce NO, thereby achieving tumor oxidative stress-based gas therapy. Both in vitro and in vivo experiments showed good tumor treatment effects, with a tumor inhibition rate of up to 90.5 % and minimal impact on normal tissues and organs. This approach demonstrates efficient loading, controlled release, and significant anti-tumor performance, offering new insights into gas and reactive oxygen species (ROS) synergistic therapy.

Nitric oxide-based multi-synergistic nanomedicine: an emerging therapeutic for anticancer

Gas therapy has emerged as a promising approach for treating cancer, with gases like NO, H2S, and CO showing positive effects. Among these, NO is considered a key gas molecule with significant potential in stopping cancer progression. However, due to its high reactivity and short half-life, delivering NO directly to tumors is crucial for enhancing cancer treatment. NO-driven nanomedicines (NONs) have been developed to effectively deliver NO donors to tumors, showing great progress in recent years. This review provides an overview of the latest advancements in NO-based cancer nanotherapeutics. It discusses the types of NO donors used in current research, the mechanisms of action behind NO therapy for cancer, and the different delivery systems for NO donors in nanotherapeutics. It also explores the potential of combining NO donors with other treatments for enhanced cancer therapy. Finally, it examines the future prospects and challenges of using NONs in clinical settings for cancer treatment.

Targeted no-releasing L-arginine-induced hesperetin self-assembled nanoparticles for ulcerative colitis intervention

Overproduction of reactive oxygen species (ROS) plays a crucial role in initiating and advancing ulcerative colitis (UC), and the persistent cycle between ROS and inflammation accelerates disease development. Therefore, developing strategies that can effectively scavenge ROS and provide targeted intervention are crucial for the management of UC. In this study, we synthesized natural carrier-free nanoparticles (HST-Arg NPs) using the Mannich reaction and π-π stacking for the intervention of UC. HST-Arg NPs are an oral formulation that exhibit good antioxidant capabilities and gastrointestinal stability. Benefiting from the negatively charged characteristics, HST-Arg NPs can specifically accumulate in positively charged inflamed regions of the colon. Furthermore, in the oxidative microenvironment of colonic inflammation, HST-Arg NPs respond to ROS by releasing nitric oxide (NO). In mice model of UC induced by dextran sulfate sodium (DSS), HST-Arg NPs significantly mitigated colonic injury by modulating oxidative stress, lowering pro-inflammatory cytokines, and repairing intestinal barrier integrity. In summary, this convenient and targeted oral nanoparticle can effectively scavenge ROS at the site of inflammation and achieve gas intervention, offering robust theoretical support for the development of subsequent oral formulations in related inflammatory interventions. STATEMENT OF SIGNIFICANCE: Nanotechnology has been extensively explored in the biomedical field, but the application of natural carrier-free nanotechnology in this area remains relatively rare. In this study, we developed a natural nanoparticle system based on hesperetin (HST), L-arginine (L-Arg), and vanillin (VA) to scavenge ROS and alleviate inflammation. In the context of ulcerative colitis (UC), the synthesized nanoparticles exhibited excellent intervention effects, effectively protecting the colon from damage. Consequently, these nanoparticles provide a promising and precise nutritional intervention strategy by addressing both oxidative stress and inflammatory pathways simultaneously, demonstrating significant potential for application.

The heterogeneity of physiological activity for chiral carbon dots derived from L/D/DL-arginine

Chirality is a ubiquitous phenomenon in nature. The advent of nanomaterials has led to a gradual evolution of chiral studies from the molecular scale to the nanoscale. The emergence of carbon dots (CDs) has inaugurated a novel domain in the scientific and technological realms of carbon nanomaterials. In recent years, CDs have attracted increasing attention due to their luminescent properties, excellent biocompatibility and remarkable bioactivity. However, little attention has been paid to the chirality of the CDs and, in particular, the differences between CDs synthesized from racemic compounds and other chiral CDs, as well as the differences in the biological effects of chiral CDs, remain to be explored. Here, chiral CDs were synthesized from L-/D-/DL-arginine, and the differences in various aspects of chiral CDs were evaluated. We found that L-CDs without extreme differences in structure had brighter fluorescence and a more significant ability of NO generation and lipid droplet inhibition than the other two chiral CDs. Combined with its better drug loading and release ability, we validated its superior efficacy in tumor treatment. Therefore, this study provides a basis for further research on chiral carbon dots and their differences.

In situ thermosensitive H2O2/NO self-sufficient hydrogel for photothermal ferroptosis of triple-negative breast cancer

L-Arginine (LA), a semi-essential amino acid in the human body, holds significant potential in cancer therapy due to its ability to generate nitric oxide (NO) continuously in the presence of inducible NO synthase (iNOS) or reactive oxygen species (ROS). However, the efficiency of NO production in tumor tissue is severely constrained by the hypoxic and H2O2-deficient tumor microenvironment (TME). To address this issue, we have developed calcium peroxide (CaO2) nanoparticles capable of supplying O2/H2O2, which encapsulate and oxidize an LA-modified lipid bilayer to enable controlled localized NO generation in the presence of ROS, synergising with a ferroptosis inducer, RSL-3 (CPIR NPs). The synthesized nanoparticles were tested in vitro for their anticancer activity in 4T1 cells. To address challenges related to specificity and frequent dosing, we developed an in situ thermosensitive injectable hydrogel incorporating CPIR nanoparticles. Cross-linking at 60 °C creates a self-sufficient formulation, releasing NO/H2O2 to combat tumor hypoxia. RSL-3 induces ferroptosis, contributing to a synergistic photothermal effect and eliminating tumor in vivo.

Custom-Design of Multi-Stimuli-Responsive Degradable Silica Nanoparticles for Advanced Cancer-Specific Chemotherapy

Chemotherapy is crucial in oncology for combating malignant tumors but often encounters obatacles such as severe adverse effects, drug resistance, and biocompatibility issues. The advantages of degradable silica nanoparticles in tumor diagnosis and treatment lie in their ability to target drug delivery, minimizing toxicity to normal tissues while enhancing therapeutic efficacy. Moreover, their responsiveness to both endogenous and exogenous stimuli opens up new possibilities for integrating multiple treatment modalities. This review scrutinizes the burgeoning utility of degradable silica nanoparticles in combination with chemotherapy and other treatment modalities. Commencing the elucidation of degradable silica synthesis and degradation mechanisms, emphasis is placed on the responsiveness of these materials to endogenous (e.g., pH, redox reactions, hypoxia, and enzymes) and exogenous stimuli (e.g., light and high-intensity focused ultrasound). Moreover, this exploration delves into strategies harnessing degradable silica nanoparticles in chemotherapy alone, coupled with radiotherapy, photothermal therapy, photodynamic therapy, gas therapy, immunotherapy, starvation therapy, and chemodynamic therapy, elucidating multimodal synergies. Concluding with an assessment of advances, challenges, and constraints in oncology, despite hurdles, future investigations are anticipated to augment the role of degradable silica in cancer therapy. These insights can serve as a compass for devising more efficacious combined tumor treatment strategies.

Recent Progress in Polyion Complex Nanoparticles with Enhanced Stability for Drug Delivery

Polyion complex (PIC) nanoparticles, including PIC micelles and PICsomes, are typically composed of poly(ethylene glycol) block copolymers coupled with oppositely charged polyelectrolytes or therapeutic agents via electrostatic interaction. Due to a simple and rapid preparation process with high drug-loading efficiency, PIC nanoparticles are beneficial to maintaining the chemical integrity and high biological activity of the loaded drugs. However, the stability of PIC nanoparticles can be disrupted in high-ionic-strength solutions because electrostatic interaction is the DRIVING force; these disruptions can thus impair drug delivery. Herein, we summarize the advances in the use of PIC nanoparticles for delivery of charged drugs, focusing on the different chemical and physical strategies employed to enhance their stability, including enhancing the charge density, crosslinking, increasing hydrophobic interactions, forming hydrogen bonds, and the development of PIC-based gels. In particular, we describe the use of PIC nanoparticles to load peptide antibiotics targeting antibiotic-resistant and biofilm-related diseases and the use of nanoparticles that load chemotherapeutics and gaseous donors for cancer treatment. Furthermore, the application of PIC nanoparticles as magnetic resonance imaging contrast agents is summarized for the first time. Therefore, this review is of great significance for advances in the use of polymeric nanoparticles for functional drug delivery.

Oxaliplatin-Loaded Mil-100(Fe) for Chemotherapy-Ferroptosis Combined Therapy for Gastric Cancer

Oxaliplatin (Oxa) is a commonly used chemotherapy drug in the treatment of gastric cancer, but its toxic side effects and drug resistance after long-term use have seriously limited its efficacy. Loading chemotherapy drugs with nanomaterials and delivering them to the tumor site are common ways to overcome the above problems. However, nanomaterials as carriers do not have therapeutic functions on their own, and the effect of single chemotherapy is relatively limited, so there is still room for progress in related research. Herein, we construct Oxa@Mil-100(Fe) nanocomposites by loading Oxa with a metal-organic framework (MOF) Mil-100(Fe) with high biocompatibility and a large specific surface area. The pore structure of Mil-100(Fe) is conducive to a large amount of Oxa loading with a drug-loading rate of up to 27.2%. Oxa@Mil-100(Fe) is responsive to the tumor microenvironment (TME) and can release Oxa and Fe3+ under external stimulation. On the one hand, Oxa can inhibit the synthesis of DNA and induce the apoptosis of gastric cancer cells. On the other hand, Fe3+ can clear overexpressed glutathione (GSH) in TME and be reduced to Fe2+, inhibiting the activity of glutathione peroxidase 4 (GPX4), leading to the accumulation of intracellular lipid peroxides (LPO), and at the same time releasing a large number of reactive oxygen species (ROS) through the Fenton reaction, inducing ferroptosis in gastric cancer cells. With the combination of apoptosis and ferroptosis, Oxa@Mil-100(Fe) shows a good therapeutic effect, and the killing effect on gastric cancer cells is obvious. In a nude mouse model of subcutaneous tumor transplantation, Oxa@Mil-100(Fe) shows a significant inhibitory effect on tumor growth, with an inhibition rate of nearly 60%. In addition to its excellent antitumor activity, Oxa@Mil-100(Fe) has no obvious toxic or side effects. This study provides a new idea and method for the combined treatment of gastric cancer.

pH/GSH dual responsive nanosystem for nitric oxide generation enhanced type I photodynamic therapy

Tumor hypoxia diminishes the effectiveness of traditional type II photodynamic therapy (PDT) due to oxygen consumption. Type I PDT, which can operate independently of oxygen, is a viable option for treating hypoxic tumors. In this study, we have designed and synthesized JSK@PEG-IR820 NPs that are responsive to the tumor microenvironment (TME) to enhance type I PDT through glutathione (GSH) depletion. Our approach aims to expand the sources of therapeutic benefits by promoting the generation of superoxide radicals (O2-.) while minimizing their consumption. The diisopropyl group within PEG-IR820 serves a dual purpose: it functions as a pH sensor for the disassembly of the NPs to release JSK and enhances intermolecular electron transfer to IR820, facilitating efficient O2-. generation. Simultaneously, the release of JSK leads to GSH depletion, resulting in the generation of nitric oxide (NO). This, in turn, contributes to the formation of highly cytotoxic peroxynitrite (ONOO-.), thereby enhancing the therapeutic efficacy of these NPs. NIR-II fluorescence imaging guided therapy has achieved successful tumor eradication with the assistance of laser therapy.

Recent advances in sulfur dioxide releasing nanoplatforms for cancer therapy

Sulfur dioxide (SO2), long considered to be a harmful atmospheric pollutant, has recently been posited as the fourth gasotransmitter, as it is produced endogenously in mammals and has important pathophysiological effects. The field of tumor therapy has witnessed a paradigm shift with the emergence of SO2-based gas therapy. This has been possible because SO2 is a potent glutathione consumer that can promote the production of reactive oxygen species, eventually leading to oxidative-stress-induced cancer cell death. Nevertheless, this therapeutic gas cannot be directly administrated in gaseous form. Thus, various nano formulations incorporating SO2 donors or prodrugs capable of storing and releasing SO2 have been developed in an attempt to achieve active/passive intratumoral accumulation and SO2 release in the tumor microenvironment. In this review article, the advances over the past decade in nanoplatforms incorporating sulfur SO2 prodrugs to provide controlled release of SO2 for cancer therapy are summarized. We first describe the synthesis of polypeptide SO2 prodrugs to overcome multiple drug resistance that was pioneered by our group, followed by other macromolecular SO2 prodrug structures that self-assemble into nanoparticles for tumor therapy. Second, we describe nanoplatforms composed of various small-molecule SO2 donors with endogenous or exogenous stimuli responsiveness, including thiol activated, acid-sensitive, and ultraviolet or near-infrared light-responsive SO2 donors, which have been used for tumor inhibition. Combinations of SO2 gas therapy with photodynamic therapy, chemotherapy, photothermal therapy, sonodynamic therapy, and nanocatalytic tumor therapy are also presented. Finally, we discuss the current limitations and challenges and the future outlook for SO2-based gas therapy. STATEMENT OF SIGNIFICANCE: Gas therapy is attracting increasing attention in the scientific community because it is a highly promising strategy against cancer owing to its inherent biosafety and avoidance of drug resistance. Sulfur dioxide (SO2) is recently found to be produced endogenously in mammals with important pathophysiological effects. This review summarizes recent advances in SO2 releasing nanosystems for cancer therapy, including polymeric prodrugs, endogenous or exogenous stimulus-activated SO2 donors delivered by nanoplatform and combination therapy strategies.