Nitric Oxide Delivery Platform Research Articles

Nanostructured Organosilica Nitric Oxide Donors Intrinsically Regulate Macrophage Polarization with Antitumor Effect.

Nitric oxide (NO) has many important biological functions; however, it has been a long-standing challenge to utilize the exogenous NO donor itself in the activation of macrophages for cancer immunotherapy. Herein, we report the synthesis of a nanoparticle-based NO delivery platform with a rational design for effective NO delivery and macrophage activation. S-Nitrosothiol (SNO) modified organosilica nanoparticles with a tetrasulfide-containing composition produced a higher level of intracellular NO than their bare silica counterparts in macrophages. Enhanced intracellular delivery of NO resulted in mitochondrial dysfunction and disruption of the tricarboxylic acid cycle, leading to macrophage activation and delayed tumor growth. This study provides insights on intracellularly delivered NO for regulating the polarization of macrophages and cancer immunotherapy.

A Nanocoating Co-Localizing Nitric Oxide and Growth Factor onto Individual Endothelial Cells Reveals Synergistic Effects on Angiogenesis.

The delivery of nitric oxide (NO)-an intrinsic cellular signaling molecule-is promising for disease treatment, in particular to vascular diseases, due to its endothelial-derived inherent nature. The limited diffusion distance of labile NO prompts researchers to develop various carriers and targeting methods for specific sites. In contrast to the apoptotic effect of NO, such as anticancer, delivering low NO concentration at the desired targeting area is still intricate in a physiological environment. In this study, the layer-by-layer assembled nanocoating is leveraged to develop a direct NO delivery platform to individual endothelial cells (ECs). NO can be localized to individual ECs via S-nitrosothiol-bound polyacrylic acid which is a polymer directly providing an endothelial-like constant level of NO. To increase angiogenic activation along with NO, VEGF is additionally applied to specific receptors on the cell surface. Notably, the survival and proliferation of ECs are significantly increased by a synergistic effect of NO and VEGF co-localized via nanocoating. Furthermore, the nanocoating remarkably promoted cell migration and tubule formation-prerequisites of angiogenesis. The proposed unique technology based on nanocoating demonstrates great potential for conferring desired angiogenic functions to individual ECs through efficient NO delivery.

Silk Nanoparticles: A Natural Polymeric Platform for Nitric Oxide Delivery in Biomedical Applications.

In this study, the preparation and characterization of nitric oxide (NO) releasing silk fibroin nanoparticles (SF NPs) are described for the first time. S-Nitroso-N-acetylpenicillamine (SNAP)-loaded SF NPs (SNAP-SF NPs) were prepared via an antisolvent/self-assembling method by adding a SNAP/ethanol solution to an aqueous SF solution and freeze-thawing. The prepared SNAP-SF NPs had a diameter ranging from 300 to 400 nm and an overall negative charge of -28.76 ± 0.73 mV. Among the different SNAP/SF ratios tested, the highest encapsulation efficiency (18.3 ± 1.3%) and loading capacity (9.1 ± 0.6%) values were attributed to the 1:1 ratio. The deconvolution of the amide I band in the FTIR spectra of SF NPs and SNAP-SF NPs showed an increase in the β-sheet content for SNAP-SF NPs, confirming the hydrophobic interactions between SNAP and silk macromolecules. SNAP-SF NPs released up to 1.31 ± 0.02 × 10-10 mol min-1 mg-1 NO over a 24 h period. Moreover, SNAP-SF NPs showed concentration-dependent antibacterial effects against methicillin-resistant Staphylococcus aureus and Escherichia coli. Furthermore, they did not elicit any marked cytotoxicity against 3T3 mouse fibroblast cells at concentrations equal to or below 2 mg/mL. Overall, these results demonstrated that SNAP-SF NPs have great potential to be used as a NO delivery platform for biomedical applications such as tissue engineering and wound healing, where synergistic properties of SF and NO are desired.

NIR-Triggered Theranostic Bi2S3 Light Transducer for On-Demand NO Release and Synergistic Gas/Photothermal Combination Therapy of Tumors.

Gaseous therapy based on nitric oxide (NO) has emerged as a potential tumor therapy route. However, the development of a NO generator with precisely controlled NO releasing in the target site is still facing enormous challenges. Herein, a typical NO delivery platform by integrating the hollow structured polydopamine (PDA) coated Bi2S3 nanohybrids (denoted as H-Bi2S3@PDA) with a heat-sensitive S-nitrosothiol (RSNO) molecule was explored for near-infrared (NIR) light-responsive on-demand NO-releasing and synergetic gas/photothermal combination therapy of tumors. The designed H-Bi2S3@PDA nanocomposites hold high photothermal conversion efficiency of 46.13% under irradiation of a NIR laser, leading to NIR light-triggered controllable generation of NO gas via breaking the S-NO bonds of the heat-sensitive RSNO molecules. More importantly, synergistic gas/photothermal therapy of the tumor was also achieved, which presented remarkable inhibition growth and ablation of tumors. These findings provide the opportunity to design a NIR light-activated NO generator with a combination of photothermal materials and heat-sensitive molecules for integrative gas/photothermal therapy in deep tumors.

Controlled and Localized Nitric Oxide Precursor Delivery From Chitosan Gels to Staphylococcus aureus Biofilms

Extracellular polymeric substances in bacterial biofilms reduce the penetration of antimicrobials and give rise to extreme recalcitrance and treatment challenges for many persistent biofilms and associated infections. Nitric oxide (NO) is a promising alternative to conventional antimicrobials but is challenging to deliver at precise concentrations for significant periods in a convenient and nontoxic manner. Here we report a unique NO delivery platform by incorporating the NO precursor isosorbide mononitrate (ISMN) into chitosan gels to facilitate sustained ISMN release and effective delivery. The chitosan gels were characterized with respect to the drug release kinetics, rheological properties, as well as antimicrobial efficacy against biofilms of Staphylococcus aureus in the absence and presence of the antibiotic ciprofloxacin. Chitosan gels loaded with ISMN alone (CS-ISMN) showed comparable antimicrobial effects compared to blank chitosan gel (approximately 2 log10 reduction). However, there was strong synergy of CS-ISMN when combined with ciprofloxacin, that is, ∼4 log10 reduction of bacterial colonies of CS-ISMN-CIP compared to the single treatments. These findings were confirmed by confocal imaging and highlight a potentially effective new way to overcome recalcitrant S aureus biofilms using NO precursors.

Localized and Controlled Delivery of Nitric Oxide to the Conventional Outflow Pathway via Enzyme Biocatalysis: Toward Therapy for Glaucoma.

Nitric oxide (NO) is able to lower intraocular pressure (IOP); however, its therapeutic effects on outflow physiology are location- and dose-dependent. A NO delivery platform that directly targets the resistance-generating region of the conventional outflow pathway and locally liberates a controlled dose of NO is reported. An increase in outflow facility (decrease in IOP) is demonstrated in a mouse model.

Controllable Generation of Nitric Oxide by Near‐Infrared‐Sensitized Upconversion Nanoparticles for Tumor Therapy

NaYbF4:Tm@NaYF4:Yb/Er upconversion nanoparticles are synthesized and then integrated with light‐sensitive nitric oxide (NO) donors (Roussin's black salt) to construct a novel near‐infrared (NIR)‐triggered on‐demand NO delivery platform. This nanocompound can absorb 980 nm NIR photons, convert them into higher energy photons and then transfer the energy to the NO donors, resulting in an efficient release of NO. By manipulating the output power of the 980‐nm NIR light, NO‐concentration‐dependent biological effects for cancer therapy can be fine‐tuned, which is investigated and confirmed in vitro. High concentrations of NO can directly kill cancer cells and low concentrations of NO can act as a potent P‐glycoprotein (P‐gp) modulator to overcome multi‐drug resistance (MDR) if combined with chemotherapy.

Synthesis and characterization of S-nitrosoglutathione-oligosaccharide-chitosan as a nitric oxide donor

Objectives: The aim of this work is to synthesize a novel stable and biodegradable nitric oxide (NO) donor polymer based on a chitosan backbone. This polymer needed to be linked to glutathione (GSH), which was nitrosated in a second step. This polymer has been developed as an NO delivery platform that could be further evaluated for an oral delivery in Crohn’s disease.Methods: The new polymer (named S-nitrosoglutathione-oligosaccharide-chitosan or SNOC) was obtained using a two-step procedure involving the linkage of GSH to chitosan via an amidine reaction followed by a post-nitrosation with NaNO2. The GSH linkage was assessed using NMR, FTIR and an Ellman’s test, whereas the final NO amount was determined by the Griess and Saville method.Results: Polymers with different numbers of NO groups were obtained (159.04 ± 64.16 µmol/g of polymer for SNOC G1 and 525.08 ± 151.35 µmol/g of polymer for SNOC G2) depending on the procedure used for production. When tested in an Ussing chamber, SNOC G2 had a sustained release of NO and nitrites for at least 6 h.Conclusion: We believe that this type of polymer is adapted for the development of various formulations, including microparticles.

A platform for nitric oxide delivery.

Nitric oxide (NO) is one of the structurally smallest pharmaceutical molecules, which shows great potential as an anti-restenosis, wound healing, anticancer, and antibacterial agent. To date, while most of the studies have focused mainly on demonstrating the versatility of the NO-releasing materials, little effort has been made on developing successful NO-delivery strategies for advancing NO-mediated therapy. Thus, the quest for a rationally designed NO-delivery system is becoming one of the important issues in the biomedical applications of NO. This feature article discusses the overall research trends in the NO-delivery, focusing mainly on the various particle-type and coating platforms. The objective of this article is not only to highlight the fundamental principle and challenges associated with NO-delivery, but also to provide insight for the further development of novel NO-delivery platforms for clinical applications in the near future.

Controlled Nitric Oxide Delivery Platform Based onS-Nitrosothiol Conjugated Interpolymer Complexes for Diabetic Wound Healing

Nitric oxide (NO) is known to play a critical role in enhancing wound healing as topical NO administration has demonstrated enhanced wound healing in diabetic animal models. However, this approach has been limited by the short duration of NO release, short half-life of NO, and instability of available NO donors. To overcome these deficiencies, we have developed a new NO delivery platform based on grafting S-nitrosothiols (RSNOs), derived from endogenous glutathione (GSH) or its oligomeric derivatives, phytochelatins (PCs), onto poly(vinyl methyl ether-co-maleic anhydride) (PVMMA), and their subsequent formation of interpolymer complexes with poly(vinyl pyrrolidone) (PVP). Such interpolymer complexes provide controlled release of NO for an extended duration (>10 days) and exhibit enhanced stability in the solid state over that of free RSNOs. The existence of intermolecular hydrogen bonding in such complexes and the formation of disulfide bonds following the NO release have been confirmed by FTIR and Raman. Preliminary wound healing study in a diabetic rat model demonstrates that, with a single topical application, the present controlled release NO delivery system can effectively accelerate wound closure as compared with the control (p < 0.05). The results suggest that the present NO releasing interpolymer complexes could be potentially useful for diabetic wound healing.