Nanocarrier-mediated Delivery Research Articles

Cystine-Modified Lignin-Copper Coordination Nanocarriers Improve the Therapeutic Efficacy of Tyrosine Kinase Inhibition via Cuproptosis.

The clinical application of tyrosine kinase inhibitors (TKIs) is rapidly growing and has emerged as a cornerstone in the treatment of both solid tumors and hematologic malignancies. However, resistance to TKI targets and disease progression remain inevitable. Nanocarrier-mediated delivery has emerged as a promising strategy to overcome the limitations of the TKI application. We utilized the facile modification of lignin polyhydroxyl groups to synthesize cystine-grafted lignin-copper coordinated nanoparticles for TKI delivery via the Mannich reaction. The materials exhibited a stable, uniform morphology and effectively encapsulated and delivered a variety of TKI inhibitors. Moreover, we optimized the fabrication process and found that the material could release the encapsulated drug in response to both pH and GSH. These nanoparticles significantly enhanced the therapeutic activity of TKIs both in vitro and in vivo through cuproptosis while demonstrating good biosafety. We propose a novel strategy for the targeted delivery of TKI inhibitors by combining cuproptosis with modified lignin. This approach not only offers new strategies for the clinical application of TKIs but also provides novel insights and inspiration for the modified use of lignin.

Functionally Modified Graphene Oxide as an Alternative Nanovehicle for Enhanced dsRNA Delivery in Improving RNAi-Based Insect Pest Control.

RNA interference (RNAi) has shown substantial promise as a sustainable pest management solution. However, the efficacy of RNAi-based insecticides heavily relies on advanced nanocarrier-mediated delivery systems. In this study, we modified raw graphene oxide into positively charged nanocarriers (GONs) tailored to bind with double-stranded RNA (dsRNA). The resulting GONs@dsRNA complexes demonstrated a small particle size (106 nm) and maintained stability under various conditions, including insect gut extracts, extreme pH, and extreme temperature. Furthermore, GONs efficiently transported dsRNA molecules into Drosophila S2 cells and Lepidoptera Sf9 cells, leading to an enhanced target transcript knockdown. Targeting the vacuolar ATPase gene, vha26, induced significant mortality and target transcript knockdown in D. suzukii adults but not in S. exigua. Finally, GONs@dsRNA complexes exhibited negligible cytotoxicity at both the cellular and organismal levels. This study demonstrates the potential of GONs as a biosafe nanovehicle for efficient dsRNA delivery into insects, presenting an alternative strategy for advancing RNAi applications in fundamental studies and pest control.

Cubosome lipid nanocarriers for delivery of ultra-short antimicrobial peptides

HypothesisAlthough antimicrobial peptides (AMPs) are a promising class of new antibiotics, their inherent susceptibility to degradation requires nanocarrier-mediated delivery. While cubosome nanocarriers have been extensively studied for delivery of AMPs, we do not currently understand why cubosome encapsulation improves antimicrobial efficacy for some compounds but not others. This study therefore aims to investigate the link between the mechanism of action and permeation efficiency of the peptides, their encapsulation efficacy, and the antimicrobial activity of these systems. ExperimentsEncapsulation and delivery of Indolicidin, and its ultra-short derivative, Priscilicidin, were investigated using SAXS, cryo-TEM and circular dichroism. Molecular dynamics simulations were used to understand the loading of these peptides within cubosomes. The antimicrobial efficacy was assessed against gram-negative (E. coli) and gram-positive (MRSA) bacteria. FindingsA high ionic strength solution was required to facilitate high loading of the cationic AMPs, with bilayer encapsulation driven by tryptophan and Fmoc moieties. Cubosome encapsulation did not improve the antimicrobial efficacy of the AMPs consistent with their high permeation, as explained by a recent ’diffusion to capture model’. This suggests that cubosome encapsulation may not be an effective strategy for all antimicrobial compounds, paving the way for improved selection of nanocarriers for AMPs, and other antimicrobial compounds.

Advances in nanocarrier-mediated delivery of chrysin: Enhancing solubility, bioavailability, and anticancer efficacy

Chrysin, a natural phytochemical compound found in various plant sources, possesses diverse pharmacological benefits, including anticancer, antioxidant, antidiabetic, neuroprotective, cardioprotective, hepatoprotective, immunoregulatory, and anti-inflammatory properties. Despite its well-documented biological activities, chrysin's low water solubility and bioavailability hinder its clinical development. This review explores the application of nanocarriers as a strategic approach to overcome these challenges and enhance the delivery of chrysin. Nanocarriers, including polymer-based nanoparticles (NPs), lipid-based NPs, and inorganic nanocarriers, have shown promise in improving the solubility, bioavailability, and tumor-targeted delivery of chrysin. The paper discusses chrysin's anticancer effects on different types of human cancers, elucidating its impact on crucial signaling pathways involved in tumorigenesis. The review categorizes and analyzes various nanocarriers, providing insights into their structural properties and drug release profiles. Among the nanocarriers, polymer-based NPs, especially those utilizing PLGA, emerge as promising strategies for chrysin encapsulation, demonstrating improvements in drug release, stability, and bioavailability. Lipid-based NPs and inorganic nanocarriers also exhibit potential in enhancing chrysin delivery. The comprehensive insights provided contribute to a deeper understanding of chrysin's pharmacological properties and its potential clinical applications, offering valuable perspectives for future research and translation into clinical settings. The review underscores the importance of selecting suitable structures for chrysin encapsulation to enhance its physicochemical properties and anticancer effects, paving the way for innovative nanomedicine approaches in cancer therapy.

The chitinase genes TuCht4 and TuCht10 are indispensable for molting and survival of Tetranychus urticae

Insect chitinases (Chts) play a crucial role in the molting process, enabling continuous growth through sequential developmental stages. Based on their high homology to insect Chts, TuCht1 (group II), TuCht4 (group I) and TuCht10 (group IV) were identified, and their roles during molting process were investigated. TuCht1 was mainly expressed in the deutonymphal stage, while TuCht4 was mainly expressed in the nymphal stage and the highest expression level of TuCht10 was observed in the larvae. Feeding RNAi assays have shown that group I TuCht4 and group Ⅳ TuCht10 are involved in mite molting. Suppression of TuCht4 or TuCht10 resulted in high mortality, molting abnormalities and the absence of distinct electron dense layers of chitinous horizontal laminae in the cuticle, as demonstrated by scanning electron microscopy and transmission electron microscopy. The nanocarrier mediated RNAi had significantly higher RNAi efficiency and caused higher mortality. The results of the present study suggest that chitinase genes TuCht4 and TuCht10 are potential targets for dietary RNAi, and demonstrates a nanocarrier-mediated delivery system to enhance the bioactivity of dsRNA, providing a potential technology for green pest management.

Therapeutic Implications of Dietary Polyphenols-Loaded Nanoemulsions in Cancer Therapy.

Cancer is one of the major causes of death worldwide, even the second foremost cause related to non-communicable diseases. Cancer cells typically possess several cellular and biological processes including, persistence, propagation, differentiation, cellular death, and expression of cellular-type specific functions. The molecular picture of carcinogenesis and progression is unwinding, and it appears to be a tangled combination of processes occurring within and between cancer cells and their surrounding tissue matrix. Polyphenols are plant secondary metabolites abundant in fruits, vegetables, cereals, and other natural plant sources. Natural polyphenols have implicated potential anticancer activity by various mechanisms involved in their antitumor action, including modulation of signaling pathways majorly related to cellular proliferation, differentiation, relocation, angiogenesis, metastatic processes, and cell death. The applications of polyphenols have been limited due to the hydrophobic nature and lower oral bioavailability that could be possibly overcome through encapsulating them into nanocarrier-mediated delivery systems, leading to improved anticancer activity. Nanoemulsions (NEs) possess diverse feasible properties, including greater surface area, modifiable surficial charge, higher half-life, site-specific targeting, and formulation imaging capability necessary to create a practical therapeutic impact, and have drawn increased attention in cancer therapy research. This review has summarized and discussed the basic concepts, classification, delivery approaches, and anticancer mechanism of various polyphenols and polyphenols-encapsulated nanoemulsions with improved cancer therapy.

Versatile Click Linker Enabling Native Peptide Release from Nanocarriers upon Redox Trigger.

Nanocarriers have shown their ability to extend the circulation time of drugs, enhance tumor uptake, and tune drug release. Therapeutic peptides are a class of drug compounds in which nanocarrier-mediated delivery can potentially improve their therapeutic index. To this end, there is an urgent need for orthogonal covalent linker chemistry facilitating the straightforward on-the-resin peptide generation, nanocarrier conjugation, as well as the triggered release of the peptide in its native state. Here, we present a copper-free clickable ring-strained alkyne linker conjugated to the N-terminus of oncolytic peptide LTX-315 via standard solid-phase peptide synthesis (SPPS). The linker contains (1) a recently developed seven-membered ring-strained alkyne, 3,3,6,6-tetramethylthiacycloheptyne sulfoximine (TMTHSI), (2) a disulfide bond, which is sensitive to the reducing cytosolic and tumor environment, and (3) a thiobenzyl carbamate spacer enabling release of the native peptide upon cleavage of the disulfide via 1,6-elimination. We demonstrate convenient "clicking" of the hydrophilic linker-peptide conjugate to preformed pegylated core-cross-linked polymeric micelles (CCPMs) of 50 nm containing azides in the hydrophobic core under aqueous conditions at room temperature resulting in a loading capacity of 8 mass % of peptide to polymer (56% loading efficiency). This entrapment of hydrophilic cargo into/to a cross-linked hydrophobic core is a new and counterintuitive approach for this class of nanocarriers. The release of LTX-315 from the CCPMs was investigated in vitro and rapid release upon exposure to glutathione (within minutes) followed by slower 1,6-elimination (within an hour) resulted in the formation of the native peptide. Finally, cytotoxicity of LTX CCPMs as well as uptake of sulfocyanine 5-loaded CCPMs was investigated by cell culture, demonstrating successful tumor cell killing at concentrations similar to that of the free peptide treatment.

Nanocarrier-Mediated Delivery of MicroRNAs for Fibrotic Diseases.

MicroRNAs (miRNAs) are endogenous noncoding RNAs that mediate the fibrotic process by regulating multiple targets. MicroRNA-based therapy can restore or inhibit miRNA expression and is expected to become an effective approach to prevent and alleviate fibrotic diseases. However, the safe, targeted, and effective delivery of miRNAs is a major challenge in translating miRNA therapy from bench to bedside. In this review, we briefly describe the pathophysiological process of fibrosis and the mechanism by which miRNAs regulate the progression of fibrosis. Additionally, we summarize the miRNA nanodelivery tools for fibrotic diseases, including chemical modifications and polymer-based, lipid-based, and exosome-based delivery systems. Further clarification of the role of miRNAs in fibrosis and the development of a novel nanodelivery system may facilitate the prevention and alleviation of fibrotic diseases in the future.

Therapeutic Potential of Nanocarrier-Mediated Delivery of Phytoconstituents for Wound Healing: Their Current Status and Future Perspective.

The treatment of wounds is a serious problem all over the world and imposes a huge financial burden on each and every nation. For a long time, researchers have explored wound dressing that speeds up wound healing. Traditional wound dressing does not respond effectively to the wound-healing process as expected. Therapeutic active derived from plant extracts and extracted bioactive components have been employed in various regions of the globe since ancient times for the purpose of illness, prevention, and therapy. About 200years ago, most medical treatments were based on herbal remedies. Especially in the West, the usage of herbal treatments began to wane in the 1960s as a result of the rise of allopathic medicine. In recent years, however, there has been a resurgence of interest in and demand for herbal medicines for a number of reasons, including claims about their efficacy, shifting consumer preferences toward natural medicines, high costs and negative side effects of modern medicines, and advancements in herbal medicines brought about by scientific research and technological innovation. The exploration of medicinal plants and their typical uses could potentially result in advanced pharmaceuticals that exhibit reduced adverse effects. This review aims to present an overview of the utilization of nanocarriers in plant-based therapeutics, including its current status, recent advancements, challenges, and future prospects. The objective is to equip researchers with a comprehensive understanding of the historical background, current state, and potential future developments in this emerging field. In light of this, the advantages of nanocarriers based delivery of natural wound healing treatments have been discussed, with a focus on nanofibers, nanoparticles, nano-emulsion, and nanogels.

Targeted Bioluminescent Imaging of Pancreatic Ductal Adenocarcinoma Using Nanocarrier-Complexed EGFR-Binding Affibody-Gaussia Luciferase Fusion Protein.

In vivo imaging has enabled impressive advances in biological research, both preclinical and clinical, and researchers have an arsenal of imaging methods available. Bioluminescence imaging is an advantageous method for in vivo studies that allows for the simple acquisition of images with low background signals. Researchers have increasingly been looking for ways to improve bioluminescent imaging for in vivo applications, which we sought to achieve by developing a bioluminescent probe that could specifically target cells of interest. We chose pancreatic ductal adenocarcinoma (PDAC) as the disease model because it is the most common type of pancreatic cancer and has an extremely low survival rate. We targeted the epidermal growth factor receptor (EGFR), which is frequently overexpressed in pancreatic cancer cells, using an EGFR-specific affibody to selectively identify PDAC cells and delivered a Gaussia luciferase (GLuc) bioluminescent protein for imaging by engineering a fusion protein with both the affibody and the bioluminescent protein. This fusion protein was then complexed with a G5-PAMAM dendrimer nanocarrier. The dendrimer was used to improve the protein stability in vivo and increase signal strength. Our targeted bioluminescent complex had an enhanced uptake into PDAC cells in vitro and localized to PDAC tumors in vivo in pancreatic cancer xenograft mice. The bioluminescent complexes could delineate the tumor shape, identify multiple masses, and locate metastases. Through this work, an EGFR-targeted bioluminescent-dendrimer complex enabled the straightforward identification and imaging of pancreatic cancer cells in vivo in preclinical models. This argues for the targeted nanocarrier-mediated delivery of bioluminescent proteins as a way to improve in vivo bioluminescent imaging.

Overcoming Malignant Glioma Therapeutic Challenges: Nanocarrier-Mediated Delivery of Immune Checkpoint Blockers via Nasal Route

Malignant glioma represents a prevailing malignancy within both paediatric and adult populations, necessitating advanced therapeutic interventions. Traditional therapeutic avenues encompassing surgical resection, radiotherapy, and chemotherapy have yielded unsatisfactory clinical outcomes

Nanocarrier-Based Delivery of SN22 as a Tocopheryl Oxamate Prodrug Achieves Rapid Tumor Regression and Extends Survival in High-Risk Neuroblastoma Models.

Despite the use of intensive multimodality therapy, the majority of high-risk neuroblastoma (NB) patients do not survive. Without significant improvements in delivery strategies, anticancer agents used as a first-line treatment for high-risk tumors often fail to provide clinically meaningful results in the settings of disseminated, recurrent, or refractory disease. By enhancing pharmacological selectivity, favorably shifting biodistribution, strengthening tumor cell killing potency, and overcoming drug resistance, nanocarrier-mediated delivery of topoisomerase I inhibitors of the camptothecin family has the potential to dramatically improve treatment efficacy and minimize side effects. In this study, a structurally enhanced camptothecin analog, SN22, reversibly coupled with a redox-silent tocol derivative (tocopheryl oxamate) to allow its optimally stable encapsulation and controlled release from PEGylated sub-100 nm nanoparticles (NP), exhibited strong NB cell growth inhibitory activity, translating into rapid regression and durably suppressed regrowth of orthotopic, MYCN-amplified NB tumors. The robust antitumor effects and markedly extended survival achieved in preclinical models recapitulating different phases of high-risk disease (at diagnosis vs. at relapse with an acquired loss of p53 function after intensive multiagent chemotherapy) demonstrate remarkable potential of SN22 delivered in the form of a hydrolytically cleavable superhydrophobic prodrug encapsulated in biodegradable nanocarriers as an experimental strategy for treating refractory solid tumors in high-risk cancer patients.

Use of Exogenous Enzymes in Human Therapy: Approved Drugs and Potential Applications.

The development of safe and efficacious enzyme-based human therapies has increased greatly in the last decades, thanks to remarkable advances in the understanding of the molecular mechanisms responsible for different diseases, and the characterization of the catalytic activity of relevant exogenous enzymes that may play a remedial effect in the treatment of such pathologies. Several enzyme-based biotherapeutics have been approved by FDA (the U.S. Food and Drug Administration) and EMA (the European Medicines Agency) and many are undergoing clinical trials. Apart from enzyme replacement therapy in human genetic diseases, which is not discussed in this review, approved enzymes for human therapy find applications in several fields, from cancer therapy to thrombolysis and the treatment, e.g., of clotting disorders, cystic fibrosis, lactose intolerance and collagen-based disorders. The majority of therapeutic enzymes are of microbial origin, the most convenient source due to fast, simple and cost-effective production and manipulation. The use of microbial recombinant enzymes has broadened prospects for human therapy but some hurdles such as high immunogenicity, protein instability, short half-life and low substrate affinity, still need to be tackled. Alternative sources of enzymes, with reduced side effects and improved activity, as well as genetic modification of the enzymes and novel delivery systems are constantly searched. Chemical modification strategies, targeted-and/or nanocarrier-mediated delivery, directed evolution and site-specific mutagenesis, fusion proteins generated by genetic manipulation are the most explored tools to reduce toxicity and improve bioavailability and cellular targeting. This review provides a description of exogenous enzymes that are presently employed for the therapeutic management of human diseases with their current FDA/EMA-approved status, along with those already experimented at the clinical level and potential promising candidates.

Nanocarrier-delivered dsRNA suppresses wing development of green peach aphids.

RNA interference (RNAi) has developed rapidly as a potential "green" pest management strategy. At present, most studies have focused on the screening of aphid lethal genes, whereas only a few studies have been conducted on wing development, which is crucial for aphid migration and plant-virus dissemination. Here, the Myzus persicae genes vestigial (vg) and Ultrabithorax (Ubx) related to wing development, were cloned. These two genes were expressed in various tissues of 3rd-instar winged aphids. The mRNA level of vg was high in 3rd-instar nymphs, whereas the expression level of Ubx was high in adults. The nanocarrier-mediated delivery system delivered double-stranded RNAs for aphid RNAi using topical and root applications. The expression levels of vg and Ubx were downregulated by 44.0% and 36.5%, respectively, using the topical application. The simultaneous RNAi of the two target genes caused 63.3% and 32.2% wing aberration rates using topical and root applications, respectively. The current study provided a promising method for controlling aphid migration to alleviate the spread of insect transmitted plant diseases.

Nanocarrier-Mediated Delivery of miRNA, RNAi, and CRISPR-Cas for Plant Protection: Current Trends and Future Directions

Current trends in plant genetic transformation technologies, i.e., designing and applying molecules like miRNA, RNAi, and CRISPR-Cas, largely enable researchers to target specific sites in the plant genome to avert the growing biotic and abiotic threats to plants. However, the delivery of these molecules through conventional techniques brings an array of drawbacks such as low efficiency due to the cell wall barrier, tissue damage that leads to browning or necrosis, degradation of these biomolecules by physiological conditions (high temperature, harsh pH, and light), and plant-specific protocols. The advancements in nanotechnology offer an excellent alternative for the safe and highly efficient delivery of biomolecules such as miRNA, CRISPR-Cas, and RNAi without damaging the plant tissues. Nanoparticle (polymeric, metallic, magnetic, silica, carbon, etc.)-based delivery of biomolecules can be efficiently utilized especially for plant protection applications. Herein, we present a comprehensive overview of current trends (with a focus on the previous five years) in nanoparticle-based delivery of miRNA, RNAi, CRISPR-Cas and simillar biomolecules for plant protection applications. In addition, a future perspective focuses on the research gaps and unexplored potentials of nanoparticles for the delivery of biomolecules.

Novel Opportunities for Cathepsin S Inhibitors in Cancer Immunotherapy by Nanocarrier-Mediated Delivery.

Cathepsin S (CatS) is a secreted cysteine protease that cleaves certain extracellular matrix proteins, regulates antigen presentation in antigen-presenting cells (APC), and promotes M2-type macrophage and dendritic cell polarization. CatS is overexpressed in many solid cancers, and overall, it appears to promote an immune-suppressive and tumor-promoting microenvironment. While most data suggest that CatS inhibition or knockdown promotes anti-cancer immunity, cell-specific inhibition, especially in myeloid cells, appears to be important for therapeutic efficacy. This makes the design of CatS selective inhibitors and their targeting to tumor-associated M2-type macrophages (TAM) and DC an attractive therapeutic strategy compared to the use of non-selective immunosuppressive compounds or untargeted approaches. The selective inhibition of CatS can be achieved through optimized small molecule inhibitors that show good pharmacokinetic profiles and are orally bioavailable. The targeting of these inhibitors to TAM is now more feasible using nanocarriers that are functionalized for a directed delivery. This review discusses the role of CatS in the immunological tumor microenvironment and upcoming possibilities for a nanocarrier-mediated delivery of potent and selective CatS inhibitors to TAM and related APC to promote anti-tumor immunity.

SiRNA nanotherapeutics: a promising strategy for anti‐HBV therapy

Chronic hepatitis B (CHB) is the most common cause of hepatocellular carcinoma (HCC) and liver cirrhosis worldwide. In spite of the numerous advances in the treatment of CHB, drugs and vaccines have failed because of many factors like complexity, resistance, toxicity, and heavy cost. New RNA interference (RNAi)-based technologies have developed innovative strategies to target Achilles' heel of the several hazardous diseases involving cancer, some genetic disease, autoimmune illnesses, and viral disorders particularly hepatitis B virus (HBV) infections. Naked siRNA delivery has serious challenges including failure to cross the cell membrane, susceptibility to the enzymatic digestion, and excretion by renal filtration, which ideally can be addressed by nanoparticle-mediated delivery systems. cccDNA formation is a significant problem in obtaining HBV infections complete cure because of strength, durability, and lack of proper immune response. Nano-siRNA drugs have a great potential to address this problem by silencing specific genes which are involved in cccDNA formation. In this article, the authors describe siRNA nanocarrier-mediated delivery systems as a promising new strategy for HBV infections therapy. Simultaneously, the authors completely represent the clinical trials which use these strategies for treatment of the HBV infections.

Microenvironment-sensing, nanocarrier-mediated delivery of combination chemotherapy for pancreatic cancer.

Limited effectiveness of Raf and MEK inhibitors has impelled the interest to use the inhibitors of Extra-cellular Receptor Kinase (ERK) pathway in combination with Gemcitabine (GEM) in pancreatic cancer. However, off-target abundance of ERK receptors, challenging physico-chemical properties, and dose-limiting toxicity of the inhibitor has presented critical challenges towards fabricating this combination amenable for clinical translation. Herein we report a pharmaceutical nanoformulation of GEM and an ERK inhibitor (SCH 772984) co-stabilized within a pH-sensing nanocarrier (NC, with a hydrodynamic diameter of 161 ± 5.0nm). The NCs were modularly derived from a triblock, self-assembling copolymer, and were chemically conjugated with GEM and encapsulated with SCH772984 at a loading content of 20.2% and 18.3%, respectively. Through pH-mediated unfolding of the individual blocks of the copolymer, the NCs were able to control the release of encapsulated drugs, traffic through cellular membranes, engage target receptors, suppress proliferation of pancreatic cancer cells, and accumulate at disease sites. Collectively our studies showed the feasibility of co-delivery of a combination chemotherapy consisting of GEM and an ERK inhibitor from a NC platform, which can sense and respond to tumor microenvironment of pancreatic cancer setting.

Slow relaxation during and after perturbation of bistable kinetics of gene expression

After a short perturbation of a bistable genetic network, it returns to its initial steady state or transits to another steady state. The time scale characterizing such transient regimes can be appreciably longer compared to those of the degradation of the perturbed mRNAs and proteins. The author shows in detail the specifics of this slowdown of the transient kinetics using mean-field kinetic equations and Monte Carlo simulations. Attention is focused on nanocarrier-mediated delivery and release of short non-coding RNA (e.g., miRNA or siRNA) into cells with subsequent suppression of the populations of the targeted mRNA and corresponding protein.

Nanocarrier-mediated Delivery of CORM-2 Enhances Anti-allodynic and Anti-hyperalgesic Effects of CORM-2.

Neuropathic pain is a devastating chronic condition and effective treatments are still lacking. Carbon monoxide-releasing molecule-2 (CORM-2) as a carbon monoxide (CO) carrier, exerts potent anti-neuropathic pain effects; however, its poor water solubility and short half-life hinder its clinical utility. Therefore, the aim of this study was to investigate whether CORM-2-loaded solid lipid nanoparticles (CORM-2-SLNs) enhance the anti-allodynic and anti-hyperalgesic effects of CORM-2 in a rat chronic constriction injury (CCI) model. CORM-2-SLNs were prepared using a nanotemplate engineering technique with slight modifications. The physiochemical properties of CORM-2-SLNs were characterized and CO release from CORM-2-SLNs was assessed using a myoglobin assay. CO was slowly released from CORM-2-SLNs, was observed, and the half-life of CO release was 50 times longer than that of CORM-2. In vivo results demonstrate that intraperitoneal administration of CORM-2-SLNs (5 and 10mg/kg/day, ip) once daily for seven consecutive days significantly reduced the mechanical allodynia and mechanical hyperalgesia compared with CORM-2 (10mg/kg/day, ip). RT-PCR and Western blot analyses on days 7 and 14, revealed that treatment with CORM-2-SLNs resulted in greater reductions in the CCI-elevated levels of heme-oxygenase-2 (HO-2); inducible nitric oxide synthase (iNOS); neuronal NOS (nNOS); and inflammatory mediators (TNF-α, IBA-1, and GFAP) in the spinal cord and dorsal root ganglions compared with treatment with CORM-2. In contrast, HO-1 and IL-10 were significantly increased in the CORM-2-SLN-treated group compared with the group treated with CORM-2. These data indicate that CORM-2-SLNs are superior to CORM-2-S in alleviating mechanical allodynia and mechanical hyperalgesia.