Controlled Release Of Nitric Oxide Research Articles

An Endocellulase-Triggered NO Targeted-Release Enzyme-Prodrug Therapy System and Its Application in Ischemia Injury.

Nitric oxide (NO) is a crucial gaseous signaling molecules in regulating cardiovascular, immune, and nervous systems. Controlled and targeted NO delivery is imperative for treating cancer, inflammation, and cardiovascular diseases. Despite various enzyme-prodrug therapy (EPT) systems facilitating controlled NO release, their clinical utility is hindered by nonspecific NO release and undesired metabolic consequence. In this study, a novel EPT system is presented utilizing a cellobioside-diazeniumdiolate (Cel2-NO) prodrug, activated by an endocellulase (Cel5A-h38) derived from the rumen uncultured bacterium of Hu sheep. This system demonstrates nearly complete orthogonality, wherein Cel2-NO prodrug maintains excellent stability under endogenous enzymes. Importantly, Cel5A-h38 efficiently processes the prodrug without recognizing endogenous glycosides. The targeted drug release capability of the system is vividly illustrated through an in vivo near-infrared imaging assay. The precise NO release by this EPT system exhibits significant therapeutic potential in a mouse hindlimb ischemia model, showcasing reductions in ischemic damage, ambulatory impairment, and modulation of inflammatory responses. Concurrently, the system enhances tissue repair and promotes function recovery efficacy. The novel EPT system holds broad applicability for the controlled and targeted delivery of essential drug molecules, providing a potent tool for treating cardiovascular diseases, tumors, and inflammation-related disorders.

Surface Engineering for Endothelium-Mimicking Functions to Combat Infection and Thrombosis in Extracorporeal Life Support Technologies.

Blood-contacting medical devices routinely fail from the cascading effects of biofouling toward infection and thrombosis. Nitric oxide (NO) is an integral part of endothelial homeostasis, maintaining platelet quiescence and facilitating oxidative/nitrosative stress against pathogens. Recently, it is shown that the surface evolution of NO can mediate cell-surface interactions. However, this technique alone cannot prevent the biofouling inherent in device failure with dynamic blood-contacting applications. This work proposes an endothelium-mimicking surface design pairing controlled NO release with an inherently antifouling polyethylene glycol interface (NO+PEG). This simple, robust, and scalable platform develops surface-localized NO availability with surface hydration, leading to a significant reduction in protein adsorption as well as bacteria/platelet adhesion. Further in vivo thrombogenicity studies show a decrease in thrombus formation on NO+PEG interfaces, with preservation of circulating platelet and white blood cell counts, maintenance of activated clotting time, and reduced coagulation cascade activation. It is anticipated that this bio-inspired surface design will enable a facile alternative to existing surface technologies to address clinical manifestations of infection and thrombosis in dynamic blood-contacting environments.

Engineering of phytic acid-coated Prussian nanoparticles for combined Nitric oxide and Low-Temperature photothermal therapy of osteosarcoma

The overall survival rate for osteosarcoma (OS) has not shown any improvement over the past three decades, highlighting the persistent challenge in diagnosing and treating this disease. Nitric oxide (NO) plays a crucial role in some forms of tumor therapy. However, achieving precise and targeted release of NO remains an obstacle in anti-tumor treatment. Given this circumstance, the utilization of near infrared (NIR) laser-induced photothermal effect offers promising potential for controlled delivery of NO. In this study, we have successfully developed a therapeutic nanoparticle, PB@SNP-PA, by loading NO donor sodium nitroprusside (SNP) into Prussian blue (PB) and coating it with phytic acid (PA) for bone targeting, achieving controlled release of NO and enhancing the anti-tumor effect under NIR laser. Moreover, PB@SNP-PA significantly impairs the mitochondria of OS cells, alleviate heat tolerance induced by heat shock proteins, and mediate apoptosis as a potential anticancer mechanism. By utilizing the bisphosphonate-adsorption property of phytic acid, we have achieved bone targeting for PB@SNP-PA, which exhibits significant intra-tumoral enrichment and remarkable anti-tumor effects in vivo by inhibiting bone dissolution. These findings suggest that PB@SNP-PA functions as a unique platform for controlled NO release, proposing a novel approach for combined anti-tumor therapy involving photothermal and gas therapies.

In vivo assessment of dual-function submicron textured nitric oxide releasing catheters in a 7-day rabbit model

Catheter-induced thrombosis is a major contributor to infectious and mechanical complications of biomaterials that lead to device failure. Herein, a dualfunction submicron textured nitric oxide (NO)-releasing catheter was developed. The hemocompatibility and antithrombotic activity of vascular catheters were evaluated in both 20 h in vitro blood loop and 7 d in vivo rabbit model. Surface characterization assessments via atomic force microscopy show the durability of the submicron pattern after incorporation of NO donor S-nitroso-N-acetylpenicillamine (SNAP). The SNAP-doped catheters exhibited prolonged and controlled NO release mimicking the levels released by endothelium. Fabricated catheters showed cytocompatibility when evaluated against BJ human fibroblast cell lines. After 20h in vitro evaluation of catheters in a blood loop, textured-NO catheters exhibited a 13-times reduction in surface thrombus formation compared to the control catheters, which had 83% of the total area covered by clots. After the 7 d in vivo rabbit model, analysis on the catheter surface was examined via scanning electron microscopy, where significant reduction of platelet adhesion, fibrin mesh, and thrombi can be observed on the NO-releasing textured surfaces. Moreover, compared to relative controls, a 63% reduction in the degree of thrombus formation within the jugular vein was observed. Decreased levels of fibrotic tissue decomposition on the jugular vein and reduced platelet adhesion and thrombus formation on the texture of the NO-releasing catheter surface are indications of mitigated foreign body response. This study demonstrated a biocompatible and robust dual-functioning textured NO PU catheter in limiting fouling-induced complications for longer-term blood-contacting device applications. Statement of significanceCatheter-induced thrombosis is a major contributor to infectious and mechanical complications of biomaterials that lead to device failure. This study demonstrated a robust, biocompatible, dual-functioning textured nitric oxide (NO) polyurethane catheter in limiting fouling-induced complications for longer-term blood-contacting device applications.The fabricated catheters exhibited prolonged and controlled NO release that mimics endothelium levels. After the 7 d in vivo model, a significant reduction in platelet adhesion, fibrin mesh, and thrombi was observed on the NO-releasing textured catheters, along with decreased levels of fibrotic tissue decomposition on the jugular vein. Results illustrate that NO-textured catheter surface mitigates foreign body response.

Engineering Nitric Oxide-Releasing Antimicrobial Dental Coating for Targeted Gingival Therapy.

Bacterial biofilms play a central role in the development and progression of periodontitis, a chronic inflammatory condition that affects the oral cavity. One solution to current treatment constraints is using nitric oxide (NO)─with inherent antimicrobial properties. In this study, an antimicrobial coating is developed from the NO donor S-nitroso-N-acetylpenicillamine (SNAP) embedded within polyethylene glycol (PEG) to prevent periodontitis. The SNAP-PEG coating design enabled a controlled NO release, achieving tunable NO levels for more than 24 h. Testing the SNAP-PEG composite on dental floss showed its effectiveness as a uniform and bioactive coating. The coating exhibited antibacterial properties against Streptococcus mutans and Escherichia coli, with inhibition zones measuring up to 7.50 ± 0.28 and 14.80 ± 0.46 mm2, respectively. Furthermore, SNAP-PEG coating materials were found to be stable when stored at room temperature, with 93.65% of SNAP remaining after 28 d. The coatings were biocompatible against HGF and hFOB 1.19 cells through a 24 h controlled release study. This study presents a facile method to utilize controlled NO release with dental antimicrobial coatings comprising SNAP-PEG. This coating can be easily applied to various substrates, providing a user-friendly approach for targeted self-care in managing gingival infections associated with periodontitis.

Nitric Oxide Photorelease from Silicone Films Doped with N-Nitroso BODIPY.

Nitric oxide (NO) is a unique biochemical mediator involved in the regulation of vital processes. Light-controllable NO releasers show promise in the development of smart therapies. Here, we present a novel biocompatible material based on polydimethylsiloxane (PDMS) doped with BODIPY derivatives containing an N-nitroso moiety that is capable of the photoinduced generation of NO. We study the green-light-induced NO-release properties with the following three methods: electrochemical gas-phase sensor, liquid-phase sensor, and the Griess assay. Prolonged release of NO from the polymer films after short irradiation by narrow-band LED light sources and a laser beam is demonstrated. Importantly, this was accompanied by no or little release of the parent compound (BODIPY-based photodonor). Silicone films with the capability of controllable and clean NO release can potentially be used as a highly portable NO delivery system for different therapeutic applications.

Applications of nitric oxide-releasing nanomaterials in dermatology: Skin infections and wound healing

Nitric oxide (NO) is produced in most cells in the skin and is an important regulator of essential cutaneous functions, including responses to UV irradiation, microbial defense, wound healing, melanogenesis and epidermal permeability barrier homeostasis. Harnessing the physiological activities of NO for therapeutic use is difficult because the molecule is highly reactive and unstable. A variety of exogenous NO delivery platforms have been developed and evaluated; however, they have limited clinical applications in dermatology due to instability and poor cutaneous penetration. NO-releasing nanomaterials overcome these limitations, providing targeted tissue delivery, and sustained and controlled NO release. This review provides a comprehensive and up-to-date evaluation of the use of NO-releasing nanomaterials in dermatology for the treatment of skin and soft tissue infections and wound healing.

Ultrasound triggered local sequential reactive oxygen species and nitric oxide release for enhanced cerasomal drug delivery

Liposomal drug delivery for tumor therapy was still suffered from low stability, limited delivering efficiency and poor tumor penetration, greatly compromising the therapeutic efficacy. Herein, a stable and ultrasound triggered cerasomal drug delivery system was developed by loading doxorubicin (DOX) into stable liposomal cerasome, which was self-assembled from cerasome-forming lipid (CFL), sonosensitizer of porphyrin lipid (PL), nitric oxide (NO) donor of DSPE-PEG2000-SNO and unsaturated phospholipids DOPC, resulting in DOX@PC-SNO with stable siloxane network and S-nitrosothiol on surface, sonosensitizer in lipid bilayer and DOX in the core. DOX@PC-SNO can prevent drug leakage during blood circulation and efficiently accumulate at the tumor site at 24 h post-injection, while controllably generate reactive oxygen species (ROS) upon local ultrasound irradiation on tumor, which can not only use for SDT, but also operate as a switch for on-demand controlled release of internal DOX and external NO, resulting in specific delivery and high penetration of chemotherapeutic drug into the deep tumor, thus greatly improved antitumor efficacy without observed side effects.

Electrospun membranes of diselenide-containing poly(ester urethane)urea for in situ catalytic generation of nitric oxide

Nitric oxide (NO) plays an important role as a signalling molecule in the biological system. Organoselenium-coated or grafted biomaterials have the potential to achieve controlled NO release as they can catalyse decomposition of endogenous S-nitrosothiols to NO. However, such biomaterials are often challenged by the loss of the catalytic sites, which can affect the stability in tissue repair applications. In this work, we prepare a diselenide-containing poly(ester urethane)urea (SePEUU) polymer with Se–Se in the backbone, which is further electrospun into fibrous membranes by blending with poly(ester urethane)urea (PEUU) without diselenide bonds. The presence of catalytic sites in the main chain demonstrates stable and long-lasting NO catalytic activity, while the porous structure of the fibrous membranes ensures uniform distribution of the catalytic sites and better contact with the donor-containing solution. PEUU/SePEUU50 in 50/50 mass ratio has a physiologically adapted rate of NO release, with a sustained generation of NO after exposure to PBS at 37 °C for 30 d. PEUU/SePEUU50 has a low hemolysis and protein adsorption, with mechanical properties in the wet state matching those of natural vascular tissues. It can promote the adhesion and proliferation of human umbilical vein endothelial cells in vitro and control the proliferation of vascular smooth muscle cells in the presence of NO generation. This study exhibits the electrospun fibrous membranes have potential for utilizing as hemocompatible biomaterials for regeneration of blood-contacting tissues.

Dual photoresponsive & water-triggered nitric oxide releasing materials based on rhodium-based metal-organic polyhedra.

The exogenous administration of nitric oxide (NO) is considered a potential therapeutic treatment against a great variety of diseases due to its significant role in multiple physiological functions. Due to the gaseous nature, short lifetime and dose- and tissue-dependent activity of this molecule, the development of new administration procedures is required to control the NO delivery in terms of dosage, timing, and location. In this work, we propose a new molecular material based on robust metal-organic polyhedra (MOPs) for controlled NO release. We select dirhodium paddlewheel complex-based cuboctahedral MOPs (RhMOP), in which NO can chemically coordinate to the open-metal sites at the axial sites of dirhodium paddlewheel moieties. We further prepare amorphous coordination polymer particles (CPPs) by connecting RhMOP with bis(imidazole) linkers at the external axial sites. Both molecular MOPs and polymeric CPPs show relevant NO payloads and the release of NO can be triggered by two different stimuli: light and humidity. We show that imidazole ligands coordinating to the external axial sites of the paddlewheel moieties tune the light-triggered NO release property. We further demonstrate that the size and the extrinsic pores of CPPs are important for enhanced NO release.

Photostimulated Extended Nitric Oxide (NO) Release from Water-Soluble Block Copolymer to Enhance Antibacterial Activity.

N-Nitrosamines are well established motifs to release nitric oxide (NO) under photoirradiation. Herein, a series of amphiphilic N-nitrosamine-based block copolymers (BCPx-NO) are developed to attain controlled NO release under photoirradiation (365 nm, 3.71 mW/cm2). The water-soluble BCPx-NO forms micellar architecture in aqueous medium and exhibits a sustained NO release of 92-160 μM within 11.5 h, which is 36.8-64.0% of the calculated value. To understand the NO release mechanism, a small molecular NO donor (NOD) resembling the NO releasing functional motif of BCPx-NO is synthesized, which displays a burst NO release in DMSO within 2.5 h. The radical nature of the released NO is confirmed by electron paramagnetic resonance (EPR) spectroscopy. The gradual NO release from micellar BCPx-NO enhances antibacterial activity over NOD and exhibits a superior bactericidal effect on Gram-positive Staphylococcus aureus. In relation to biomedical applications, this work offers a comprehensive insight into tuning light-triggered NO release to improve antibacterial activity.

Ultrafast photoactivated nitric oxide release with a pyrene fluorescence probe

Nitric oxide (NO) plays important roles in both physiology and therapeutics. Nonetheless, the in-situ monitoring of NO release from most existing donors is challenging, inhibiting advanced research in both chemistry and biology. In this study, we introduce an innovative photochemotherapeutic agent that incorporates a nitroaniline NO moiety with an integrated pyrene fluorophore. This design enables controlled NO release upon light irradiation, allowing for precise quantification through a dramatic fluorescence enhancement (with a 3000-fold increase in intensity). Ultrafast spectroscopy data revealed that the NO release process is exceptionally rapid, completing within 13.3 ps. Additionally, the donor's fluorescence was successfully utilized for in situ cell imaging upon direct photoexcitation. Consequently, using this fluorescent probe enables the accurate visualization of NO release kinetics, dosage, and localization in real-time. The unique advantages of this NO donor are anticipated to significantly advance research in NO chemistry and biology.

Polypyrrole hydrogel with near-infrared light-driven nitric oxide release and photothermal activities for rapid synergistic sterilization and infected wound therapy

Developing low-cost and easy-accessible phototherapy agents with a high sterilization efficiency is urgently needed tackling the increasingly dangerous of bacterial infections. Herein, a broad-spectrum antimicrobial agent (i.e., PP-Mo-NO) with near-infrared laser (NIR) driven nitric oxide (NO) release capacity derived from the assemble of a heat-sensitive NO donor (N, N′-di-sec-butyl-N, N′-dinitroso-1, 4-phenylenediamine, BNN6) with freeze-dried three-dimensional polypyrrole hydrogel crosslinked by the sulfonated dimolybdenum-salen (PP-Mo), was synthesized for the rapid and effective eradicating of Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Upon 808 nm laser irradiation, PP-Mo-NO showed not only superb photothermal efficacy (79.88 %), but also precisely controllable NO release capacity, generating oxidative/nitrosative stress. Within 10 mins of irradiation (1.0 W cm−2), PP-Mo-NO with co-amplified photothermal (PTT)/NO synergetic antibacterial activity presented sterilization rates beyond 99.1% against both the E. coli and S. aureus at a relatively low concentration (100 µg mL−1). Meanwhile, in vivo experiments demonstrated the great application potential of PP-Mo-NO which could effectively kill bacteria at the site of infection, and repair the open infectious wounds, thereby accelerating the tissue reconstruction.

(093) The Light-Controlled Nitric Oxide Donor “NORD-1” may Improve Erectile Function Without Hypotension and Tissue Damage in Rats With Neurogenic Erectile Dysfunction

Abstract Introduction Radical prostatectomy (RP) often causes erectile dysfunction (ED) because of cavernous nerve damage during surgery. This damage results in a decrease of nitric oxide (NO) in the penile corpus cavernosum. Therefore, NO supplementation is considered to be effective for post RP ED. However, NO has systemic side effects such as headache and hypotension. Recently, a red-light-controlled NO donor “NORD-1”, developed by our group, enables spatially and temporally controlled NO release by light irradiation. Our previous study reported that NORD-1 combined with red-light irradiation is effective for neurogenic ED model rats with bilateral cavernous nerve injury (BCNI). However, the side effects of the treatment have not yet been discussed. Objective The study aimed to investigate the potency of side effects associated with the combination of NORD-1 and red-light irradiation, using a ED rat model with BCNI. Methods In this study, eight-week-old male Wistar-ST rats were used. The rats were divided into four groups: Sham+SiR650 (control compound), Sham+NORD-1, BCNI+SiR650, and BCNI+NORD-1 (n=6). The sham or BCNI surgery was performed under anesthesia in each group. BCNI surgery was performed by crushing the cavernous nerves bilaterally. Four weeks post-surgery, erectile function before and after the injection of each reagent into the penile corpus cavernosum was evaluated based on the changes in intracavernous pressure (ICP) under electrostimulation of the cavernous nerve. After the administration of each reagent, the changes in ICP with and without light irradiation were also evaluated. ICP during electrostimulation was totally measured three times; once without reagent and light, once with reagent and without light and once with reagent and light. The variations in systemic arterial pressure during electrostimulation were also analyzed. After the experiment, penile samples were collected to observe NORD-1 localization using a fluorescence microscope. In addition, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to evaluate apoptosis in the corpus cavernousm. Results Before administering each reagent without light irradiation, the ICP/mean arterial pressure (MAP) ratios under stimulation in the BCNI+SiR650 and BCNI+NORD-1 groups were significantly lower than those in the Sham+SiR650 (P < 0.01) and Sham+NORD-1 (P < 0.05) groups. After administering each reagent without light irradiation, the ICP/MAP ratios in the BCNI+SiR650 and BCNI+NORD-1 groups remained significantly lower than those in the Sham+SiR650 and Sham+NORD-1 group (P < 0.05 and P < 0.01, respectively). After administering each reagent with light irradiation, the ICP/MAP ratios in the Sham+NORD-1 and BCNI+NORD-1 groups were significantly higher than those in the Sham+SiR650 (P < 0.01) and BCNI+NORD-1 (P < 0.01) groups, respectively. The changes of MAP during electrostimulation were not different under three different conditions in all four groups. Fluorescence of NORD-1 was detected only in corpus cavernousum which means it was not detected in urethra and dorsal vein of penis. Apoptosis was not detected in corpus cavernousum in all four groups. Conclusions The combination of NORD-1 and light irradiation is effective for neurogenic ED in rats with cavernous nerve injury. The treatment may not cause hypotension and tissue damage. Disclosure No

PHMB modified photothermally triggered nitric oxide release nanoplatform for precise synergistic therapy of wound bacterial infections

Bacterial infection has been considered as a significant obstacle for wound healing. Nitric oxide (NO), as a novel alternative for antibiotics, has emerged as a promising antibacterial agent. However, the precise spatiotemporal controlled release of NO still remains a major challenge. Herein, a near-infrared (NIR) light triggered NO release nanoplatform (designated as PB-NO@PDA-PHMB) with enhanced broad-spectrum antibacterial and anti-biofilm properties was constructed. Given that PB-NO@PDA-PHMB has strong absorption in the NIR region and exhibits excellent photothermal effect, it can rapidly trigger NO release by NIR irradiation. PB-NO@PDA-PHMB can effectively contact and capture bacteria, and then exhibit synergistic effect of photothermal and gas therapy. In vitro and in vivo experiments indicated that PB-NO@PDA-PHMB exhibited excellent biocompatibility, satisfactory synergistic antibacterial efficacy and the capability of accelerating wound healing. Under NIR irradiation (808 nm, 1 W cm−2, 7 min), PB-NO@PDA-PHMB (80 μg mL−1) achieved 100% bactericidal activity against both Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphyloccocus aureus (S. aureus), removed 58.94% of S. aureus biofilm. Therefore, this all-in-one antibacterial nanoplatform with high NIR responsiveness provides a promising antibiotic-free strategy for bacterial infection treatment.

Multiple Stimuli‐Responsive Nanozyme‐Based Cryogels with Controlled NO Release as Self‐Adaptive Wound Dressing for Infected Wound Healing

AbstractWound with drug‐resistant bacterial infections has become a serious challenge for the healthcare system, and designing wound dressing to self‐adapt to the need of different stage of wound healing remains challenging. Herein, self‐adaptive wound dressings with multiple stimuli‐responsiveness and antibacterial activity are developed. Specifically, MoS2 carrying a reactive oxygen species (ROS) responsive nitric oxide (NO) release precursor L‐arginine (MSPA) is designed and incorporated into carboxymethyl chitosan/poly(N‐isopropylacrylamide) based cryogels (CMCS/PNIPAM) with multiple responsiveness (pH, near infrared (NIR), and temperature) to form self‐adaptive antibacterial cryogels that adapt to the therapeutic needs of different stages in infected wound healing. In response to the slightly acidic environment of bacterial infection, the cryogels assist the bacterial capture capacity through acid‐triggered protonation behavior, and effectively enhance the photodynamic antibacterial efficiency. Controllable on‐demand delivery of ROS, NO, and remote management of infected biofluid are achieved with NIR light as a trigger switch. The multiple stimuli‐responsive nanozyme‐based cryogels efficiently eliminate MRSA bacterial biofilm through NO assisted photodynamicand photothermal therapy (PDT&PTT). The multiple enzyme‐like activities of the cryogels effectively relieved oxidative damage. Notably, these cryogels effectively reduce wound infection, alleviated oxidative stress, and accelerate collagen deposition and angiogenesis in infected wounds, indicating that multiple stimuli‐responsive self‐adaptive wound dressings provide new ideas for infected wound treatment.

Focused ultrasound for the remote modulation of nitric oxide release from injectable PEG-fibrinogen hydrogels for tendon repair

Introduction: Tendon disorders such as tendinosis, the degradation of collagen in tendon, or tendonitis, inflammation of tendon tissue, contribute to 30% of musculoskeletal complaints. To address the limitations of currently available treatments for tendon repair, an injectable polyethylene glycol (PEG)-fibrinogen hydrogel encompassing nitric oxide (NO) releasing µ-particles was generated. The release of nitric oxide, a therapeutic molecule that modulates many wound healing processes, from the hydrogel can be modified with thermal and mechanical stimulus. To achieve remote control over NO release from hydrogels after deployment, focused ultrasound (FUS) was explored as it provides highly controlled thermal and mechanical stimulus non-invasively.Methods: In this work, the ability of FUS to remotely elicit on-demand NO generation from acoustically active composite hydrogels via thermal and/or mechanical stimulus was explored. Specifically, the temperature and time-dependent release of NO was simulated and characterized when applying FUS to composite hydrogels.Results: Results from acoustic simulations as well as thermocouple heating studies indicated that high spatial and temporal control over hydrogel warming could be achieved non-invasively with a 3.5 MHz FUS transducer. FUS was also able to remotely control NO release from hydrogels with various thermal magnitudes and durations. Additionally, no apparent changes in the mechanical properties of hydrogels were observed with FUS treatment.Discussion: Utilizing FUS thermal and mechanical stimulus provides a potential method of remotely controlling NO release from hydrogels at a wound site to aid in tendon repair.

Construction of a multifunctional peptide nanoplatform for nitric oxide release and monitoring and its application in tumor-bearing mice

As a “star molecule”, nitric oxide (NO) either promotes or inhibits many physiological processes depending on its concentration. The in situ generation and monitoring of therapeutic gas molecules has been a problem that many researchers have been working to address due to the stochastic nature of gas molecule movement. There are still relatively few studies using short peptides as NO storage systems, and there are still challenges in monitoring NO release in situ with real-time imaging over long periods of time. In this work, a morphologically transformable NO release, diagnosis and treatment integrated multifunctional nanoplatform was fabricated. A new NO-activated probe (DPBTD) with emission in the first near infrared (NIR-I) region was encapsulated into the hydrophobic domains of Ac-KLVFFAL-NH2 peptide derivatives as a biosensor for NO release. Peptide scaffolds were endowed with the capacity of controlled NO release by the introduction of NO donor (organic nitrates). Interestingly, morphology of the nanoplatform could be transformed from one-dimensional (1D) nanowires to two-dimensional (2D) nanosheets via nanorods transition state under tip sonication, which was allowed for better cell uptake. Eventually, this nanocarrier was used for stimuli-responsive NO release, real-time imaging and treatment in tumor tissues of 4T1 tumor-bearing mice. This strategy expands the application potential of peptide-based nanomaterials and provides ideas for monitoring the progress of gas-mediated cancer therapy.

L-Arginine-Modified CoWO4 /FeWO4 S-Scheme Heterojunction Enhances Ferroptosis against Solid Tumor.

Ferroptosis has recently attracted much attention as an anti-tumor therapy. Evidence suggests that ferroptosis can induce oxidative stress and accumulation of lethal lipid peroxides in cancer cells, leading to cell damage. However, unsuitable pH, H2 O2 levels, and high glutathione (GSH) expression in the tumor microenvironment hinder the development of ferroptosis-mediated therapy. In this study, an l-arginine (l-arg)-modified CoWO4 /FeWO4 (CFW) S-scheme heterojunction is strategically designed and constructed for ultrasound (US)-triggered sonodynamic- and gas therapy-induced ferroptosis. CFW not only has excellent Fenton-catalytic activity, outstanding GSH consumption capacity, and excellent ability to overcome tumor hypoxia, but its S-scheme heterostructure can also avoid the rapid combination of electron (e) and hole (h+ ) pairs, thereby enhancing the sonodynamic effects. As a precursor of nitric oxide (NO), l-arg is modified on the surface of CFW (CFW@l-arg) to achieve controlled NO release under US irradiation, thereby enhancing ferroptosis. In addition, poly(allylamine hydrochloride) is further modified on the surface of CFW@l-arg to stabilize l-arg and achieve controllable NO release. Both in vitro and in vivo results demonstrate that such a multifunctional therapeutic nanoplatform can achieve high therapeutic efficacy through sonodynamic and gas therapy-enhanced ferroptosis. This designed oncotherapy nanoplatform provides new inspiration for ferroptosis-mediated therapy.

Nitric Oxide (NO) as a Reagent for Topochemical Framework Transformation and Controlled NO Release in Covalent Organic Frameworks

Covalent organic frameworks (COFs) have emerged as versatile platforms for the separation and storage of hazardous gases. Simultaneously, the synthetic toolbox to tackle the "COF trilemma" has been diversified to include topochemical linkage transformations and post-synthetic stabilization strategies. Herein, we converge these themes and reveal the unique potential of nitric oxide (NO) as a new reagent for the scalable gas-phase transformation of COFs. Using physisorption and solid-state nuclear magnetic resonance spectroscopy on 15N-enriched COFs, we study the gas uptake capacity and selectivity of NO adsorption and unravel the interactions of NO with COFs. Our study reveals the clean deamination of terminal amine groups on the particle surfaces by NO, exemplifying a unique surface passivation strategy for COFs. We further describe the formation of a NONOate linkage by the reaction of NO with an amine-linked COF, which shows controlled release of NO under physiological conditions. NONOate-COFs thus show promise as tunable NO delivery platforms for bioregulatory NO release in biomedical applications.