A Fluorinated Bola‐Amphiphilic Dendrimer for On‐Demand Delivery of siRNA,via Specific Response to Reactive Oxygen Species

Functional materials capable of responding to stimuli intrinsic to diseases are extremely important for specific drug delivery at the disease site. However, developing on‐demand stimulus‐responsive vectors for targeted delivery is highly challenging. Here, a stimulus‐responsive fluorinated bola‐amphiphilic dendrimer is reported for on‐demand delivery of small interfering RNA (siRNA) in response to the characteristic high level of reactive oxygen species (ROS) in cancer cells. This dendrimer bears a ROS‐sensitive thioacetal in the hydrophobic core and positively charged poly(amidoamine) dendrons at the terminals, capable of interacting and compacting the negatively charged siRNA into nanoparticles to protect the siRNA and promote cellular uptake. The ROS‐sensitive feature of this dendrimer boosts specific and efficient disassembly of the siRNA/vector complexes in ROS‐rich cancer cells for effective siRNA delivery and gene silencing. Moreover, the fluorine tags in the vector enable ¹⁹F‐NMR analysis of the ROS‐responsive delivery process. In addition, this ingenious and distinct bola‐amphiphilic dendrimer is also able to combine the advantageous delivery features of both lipid and dendrimer vectors. Therefore, it represents an innovative on‐demand stimulus‐responsive delivery platform.     

IL4‐Receptor‐Targeted Dual Antitumoral Apoptotic Peptide—siRNA Conjugate Lipoplexes

Targeted delivery remains the major limitation in the development of small interfering RNA (siRNA) therapeutics. The successful siRNA multistep delivery requires precise carriers of substantial complexity. To achieve this, a monodisperse carrier is presented, synthesized by solid‐phase supported chemistry. The sequence‐defined assembly contains two oleic acids attached to a cationizable oligoaminoamide backbone in T‐shape configuration, and a terminal azide functionality for coupling to the atherosclerotic plaque‐specific peptide‐1 (AP‐1) as the cell targeting ligand for interleukin‐4 receptor (IL‐4R) which is overexpressed in a variety of solid cancers. For combined cytosolic delivery with siRNA, different apoptotic peptides (KLK, BAK, and BAD) are covalently conjugated via bioreversible disulfide linkage to the 5′‐end of the siRNA sense strand. siRNA‐KLK conjugates provide the highest antitumoral potency. The optimized targeted carrier is complexed with dual antitumoral siEG5‐KLK conjugates. The functionality of each subdomain is individually confirmed. The lipo‐oligomer confers stable assembly of siRNA conjugates into spherical 150–250 nm sized nanoparticles. Click‐shielding with dibenzocyclootyne‐PEG‐AP‐1 (DBCO‐PEG‐AP‐1) mediates an IL‐4R‐specific cell targeting and gene silencing in tumor cells. Most importantly, formulation of the siEG5‐KLK conjugate displays enhanced apoptotic tumor cell killing due to the combined effect of mitotic arrest by EG5 gene silencing and mitochondrial membrane disruption by KLK.     

A Fabricated siRNA Nanoparticle for Ultralong Gene Silencing In Vivo

Persistent gene silencing is crucially required for the successful therapeutics of short interfering RNA (siRNA). Here, a nanoparticle‐based delivery system is presented which assembles by layering siRNAs between protease degradable polypeptides to extend the therapeutic window. These tightly packed nanoparticles are efficiently taken up by cells by endocytosis, and the fabricated siRNAs are gradually released following intracellular degradation of the polypeptide layers. During cell division, the particles are distributed to the daughter cells. Due to the slow degradation through the multiple layers, the particles continuously release siRNA in all cells. Using this controlled release construct, the in vivo gene silencing effect of siRNA is consistent for an ultralong period of time (>3 weeks) with only a single treatment.     

Cypate‐Conjugated Porous Upconversion Nanocomposites for Programmed Delivery of Heat Shock Protein 70 Small Interfering RNA for Gene Silencing and Photothermal Ablation

Synergistic therapy is an accepted method of enhancing the efficacy of cancer therapies. In this study, cypate‐conjugated porous NaLuF₄ doped with Yb³⁺, Er³⁺, and Gd³⁺ is synthesized and its potential for upconversion luminescence/magnetic resonance dual‐modality molecular imaging for guiding oncotherapy is tested. Loading cypate‐conjugated upconversion nanoparticles (UCNP‐cy) with small interfering RNA gene against heat shock protein 70 (UCNP‐cy‐siRNA) enhances the cell damage. UCNP‐cy‐siRNA exhibits remarkable antitumor efficacy in vivo as a result of the synergistic effects of gene silencing and photothermal therapy, with low drug dose and minimal side effects. This result thus provides an explicit strategy for developing next‐generation multifunctional nanoplatforms for multimodal imaging‐guided synergistic oncotherapy.     

Biodegradable Dextran Nanogels for RNA Interference: Focusing on Endosomal Escape and Intracellular siRNA Delivery

The successful therapeutic application of small interfering RNA (siRNA) largely relies on the development of safe and effective delivery systems that are able to guide the siRNA therapeutics to the cytoplasm of the target cell. In this report, biodegradable cationic dextran nanogels are engineered by inverse emulsion photopolymerization and their potential as siRNA carriers is evaluated. The nanogels are able to entrap siRNA with a high loading capacity, based on electrostatic interaction. Confocal microscopy and flow cytometry analysis reveal that large amounts of siRNA‐loaded nanogels can be internalized by HuH‐7 human hepatoma cells without significant cytotoxicity. Following their cellular uptake, it is found that the nanogels are mainly trafficked towards the endolysosomes. The influence of two different strategies to enhance endosomal escape on the extent of gene silencing is investigated. It is found that both the application of photochemical internalization (PCI) and the use of an influenza‐derived fusogenic peptide (diINF‐7) can significantly improve the silencing efficiency of siRNA‐loaded nanogels. Furthermore, it is shown that an efficient gene silencing requires the degradation of the nanogels. As the degradation kinetics of the nanogels can easily be tailored, these particles show potential for intracellular controlled release of short interfering RNA.     

Dextran Microgels for Time‐Controlled Delivery of siRNA

To apply siRNA as a therapeutic agent, appropriate attention should be paid to the optimization of the siRNA gene silencing effect, both in terms of magnitude and duration. Intracellular time‐controlled siRNA delivery could aid in tailoring the kinetics of siRNA gene knockdown. However, materials with easily tunable siRNA release properties have not been subjected to thorough investigation thus far. This report describes cationic biodegradable dextran microgels which can be loaded with siRNA posterior to gel formation. Even though the siRNAs are incorporated in the hydrogel network based on electrostatic interaction, still a time‐controlled release can be achieved by varying the initial network density of the microgels. To demonstrate the biological functionality of the siRNA loaded gels, we studied their cellular internalization and enhanced green fluorescent protein (EGFP) gene silencing potential in HUH7 human hepatoma cells.     

Multifunctional Glyco‐Nanofibers: siRNA Induced Supermolecular Assembly for Codelivery In Vivo

Targeted codelivery and controlled release of drug/siRNA (small interfering RNA) in a safe and effective vehicle hold great promises for overcoming drug resistance and optimal efficacy in cancer treatment; however, rational design and preparation of such vehicles remain a critical challenge. Thus, glyco‐nanofibers (GNFs) are fabricated via supermolecular assembly of polyanionic siRNA and cationic vesicles to simultaneously deliver siRNA and doxorubicin hydrochloride (DOX) in vitro and in vivo. The vesicles are created through self‐assembly of a positively charged amphiphilic lactose derivative featuring a lactose moiety and a ferrocenium unit on either end of the molecule. The GNFs display excellent biocompatibility, enhanced cell‐penetrating ability, and hepatoma targetability. The high transport efficiency of siRNA, effective gene silencing ability, and enhanced cytotoxicity to HepG2 cells of GNFs loaded with DOX are observed in vitro. Furthermore, in vivo experiments show reduced systemic toxicity and enhanced therapeutic efficacy of DOX to both HepG2 and HepG2/ADR subcutaneous tumor‐bearing nude mice. This work proves the electrostatic self‐assembly between cationic carbohydrates and polyanionic siRNA to be a convenient and effective strategy to fabricate a single vehicle for safe and effective codelivery of drug/siRNA, which can be used to combine chemo‐ and gene‐therapy against cancers and other diseases.     

Soft Nanostructured Films for Actuated Surface‐Based siRNA Delivery

Substrate‐mediated gene delivery is an emerging technology that enables spatial control of gene expression and localized delivery. This is of particular interest for siRNA where surface‐based release can greatly impact the fields of stem‐cell reprograming, wound healing, and medical device coatings in general. However, reports on the use of siRNA for substrate‐mediated delivery are scarce and have suffered from low efficiency. Here, an alternative strategy is reported by designing self‐assembled substrates that experience stimuli‐responsive topological transformations. Specifically, a methodology is established to promote the molecular organization of lipid films having 3D‐bicontinuous cubic, 2D‐inverted hexagonal, or 1D‐lamellar nanostructures encapsulating siRNA. In response to a compositional, temperature, or humidity stimulus, the nanostructures evolve from 1D‐lamellar or 2D‐hexagonal to 3D‐cubic resulting in efficient siRNA release to human cell cultures. Grazing incidence X‐ray diffraction reveals that film nanostructures are highly ordered and preferentially aligned. The results indicate that film structure substantially affects siRNA delivery, with the supported 3D‐bicontinuous cubic phase yielding the most effective reduction of gene expression. Subsequent studies suggest this enhanced performance arises due to the ability of this phase to cross cell membranes, particularly those of endocytic compartments. This work underpins that nanostructure tuning is decisive to the performance of therapeutic films.     

Nano‐Self‐Assembly of Nucleic Acids Capable of Transfection without a Gene Carrier

Nonviral gene carriers based on electrostatic interaction, encapsulation, or absorption require a large amount of polymer carrier to achieve reasonable transfection efficiencies. With cationic nanoparticles, for example, genes interact only with the surface of the nanoparticles, resulting in a low surface area to volume ratio (SA/V = 3/r). A large volume of carrier, therefore, is required to deliver a small copy number of genes. In this study, it is demonstrated that a nano‐self‐assembly of nucleic acids transfects itself into cells spontaneously, without the need for a gene carrier. The cellular uptake of this nanoassembly occurs through a number of endocytosis mechanisms. Once within the cell, the nanoassembly can escape endolysosomal vesicles and facilitate gene transfection. This nano‐self‐assembly consisting of zinc and plasmid DNA or siRNA, termed the Zn/DNA or Zn/siRNA nanocluster, is formed through the binding of Zn²⁺ ions to the phosphate groups of nucleic acids. The method described in this paper represents a new platform for carrier‐free gene delivery that can be used to deliver any plasmid DNA or siRNA without the requirement for a specific modification in the nucleic acids or complicated steps to prepare dense particles.     

Dual Targeted Immunotherapy via In Vivo Delivery of Biohybrid RNAi‐Peptide Nanoparticles to Tumor‐Associated Macrophages and Cancer Cells

Lung cancer is associated with very poor prognosis and considered one of the leading causes of death worldwide. Here, highly potent and selective biohybrid RNA interference (RNAi)‐peptide nanoparticles (NPs) are presented that can induce specific and long‐lasting gene therapy in inflammatory tumor associated macrophages (TAMs), via an immune modulation of the tumor milieu combined with tumor suppressor effects. The data here prove that passive gene silencing can be achieved in cancer cells using regular RNAi NPs. When combined with M2 peptide–based targeted immunotherapy that immuno‐modulates TAMs cell population, a synergistic effect and long‐lived tumor eradication can be observed along with increased mice survival. Treatment with low doses of siRNA (ED₅₀ 0.0025–0.01 mg kg^?1) in a multi and long‐term dosing system substantially reduces the recruitment of inflammatory TAMs in lung tumor tissue, reduces tumor size (≈95%), and increases animal survival (≈75%) in mice. The results here suggest that it is likely that the combination of silencing important genes in tumor cells and in their supporting immune cells in the tumor microenvironment, such as TAMs, will greatly improve cancer clinical outcomes.     

Lung‐Endothelium‐Targeted Nanoparticles Based on a pH‐Sensitive Lipid and the GALA Peptide Enable Robust Gene Silencing and the Regression of Metastatic Lung Cancer

The development of efficient gene delivery systems targeting the lung endothelium remains a serious challenge. This study reports on the design and optimization of a multifunctional envelope‐type nanodevice (MEND) for an efficient siRNA delivery to the lung endothelium based on GALA‐peptide targeting ability. The incorporation of a pH‐sensitive lipid (YSK05) results in a dramatic improvement in silencing efficiency by enhancing endosomal escape, but this also causes a reduction in the lung selectivity. Contrary to the assumption that active targeting is largely dependent on the presence of a targeting ligand, the findings of the present study indicate that nanocarrier composition is critical for achieving the organ selectivity. Interestingly, helper lipids substantially mask the liver delivery resulting in optimum lung targeting. The optimized YSK05‐MEND is 40‐fold more efficient than a previously developed MEND, with a robust lung endothelium gene knockdown at small doses. The YSK05‐MEND strongly inhibits a metastatic lung cancer model and exerts superior control over lung metastasis compared to chemotherapy or the previously developed MEND. The YSK05‐MEND is well‐tolerated in mice after acute or chronic administration. As far as it is known, YSK05‐MEND achieves the most efficient lung endothelium gene silencing reported thus far with a median effective dose of 0.01 mg siRNA kg^?1 while minimally affecting the endothelium of other organs.     

Forming Covalent Crosslinks between Polymer‐Grafted Nanoparticles as a Route to Highly Filled and Mechanically Robust Nanocomposites

Filler aggregation in polymer matrix nanocomposites leads to inhomogeneity in particle distribution and deterioration of mechanical properties. The use of polymer‐grafted nanoparticles (PGNPs) with polymers directly attached to the particle surfaces precludes aggregation of the filler. However, solids composed of PGNPs are mechanically weak unless the grafted chains are long enough to form entanglements between particles, and requiring long grafts limits the achievable filler density of the nanocomposite. In this work, long, entangled grafts are replaced with short reactive polymers that form covalent crosslinks between particles. Crosslinkable PGNPs, referred to as XNPs, can be easily processed from solution and subsequently cured to yield a highly filled yet mechanically robust composite. In this specific instance, silica nanoparticles are grafted with poly(glycidyl methacrylate), cast into films, and crosslinked with multifunctional amines at elevated temperatures. Indentation and scratch experiments show significant enhancement of hardness, modulus, and scratch resistance compared to non‐crosslinked PGNPs and to crosslinked polymer films without nanoparticle reinforcement. Loadings of up to 57 wt% are achieved while yielding uniform films that deform locally in a predominantly elastic manner. XNPs therefore potentially allow for the formulation of robust nanocomposites with a high level of functionality imparted by the selected filler particles.     

Tumor‐Specific Self‐Degradable Nanogels as Potential Carriers for Systemic Delivery of Anticancer Proteins

Development of a safe and effective carrier for systemic protein delivery is highly desirable, which depends on management of the relationship among loading capacity, stability, delivery efficiency, and degradability. Here, a tumor‐specific self‐degradable nanogel composed of hyaluronidase (HAase)‐degradable hyaluronic acid (HA) matrices entrapping acid‐activatable HAase (aHAase) for systemic delivery of anticancer proteins is reported. Collaboratively crosslinked nanogels (cNG) obtained by the synthetic cholesteryl methacrylated HA show high protein‐loading capacity and stability. The aHAase is engineered by modifying the HAase with citraconic anhydride to shield its HA‐degrading activity, which can be reversibly activated by hydrolysis of the citraconic amide under acidic condition. In the tumor microenvironment, the mild acidity activates the aHAase partially, which results in swelling of the cNG and releasing of the aHAase. The released reactivated aHAase can degrade the HA that is also a major constituent of tumor extracellular matrix to increase perfusion of the cNG in the tumor stroma. In the acidic endocytic vesicles, the aHAase is fully reactivated. The active aHAase completely degrades the cNG to release the encapsulated anticancer protein, deoxyribonuclease I intracellularly, which digests the DNA to cause tumor cell death for enhanced antitumor efficacy.     

MMP-2 Responsive Unidirectional Hydrogel-Electrospun Patch Loading TGF-β1 siRNA Polyplexes for Peritendinous Anti-Adhesion

Bio-derived hydrogel patch systems exhibit promising potential in localized drug delivery for the prevention and treatment of various diseases. However, the uncontrolled release from the hydrogel patch both in time and space, is not an optimal strategy for peritendinous anti-adhesion, leading to transient effect and unnecessary diffusion of therapeutics. Here, an innovative composite anti-adhesion patch is designed for on-demand and unidirectional polyplexes delivery to inhibit fibroblasts proliferation and collagen deposition by silencing fibrosis gene transforming growth factor-β1 (TGF-β1). Firstly, a metalloproteinase-2 (MMP-2) degradable hydrogel is prepared by crosslinking allyl glycidyl ether (AGE) modified carboxymethyl chitosan (CMCS-AGE) with MMP-2 substrate peptide CPLGLAGC (MMP-2 sp). Then, the hydrogel loading TGF-β1 siRNA polyplexes are attached onto polycaprolactone (PCL) electrospun fibers to form a composite bilayer patch. The hydrogel–electrospun fibers (H–E) patch shows MMP-2-responsive and unidirectional release behaviors of encapsulated TGF-β1 siRNA polyplexes and associated gene silencing effect on TGF-β1, leading to the inhibition of fibroblasts proliferation. Moreover, after implanting the H–E patch by wrapping the repaired tendon, the formation of adhesion tissue is responsively attenuated in MMP-2 overexpression microenvironment. This study presents a promising approach employing a composite bilayer patch with on-demand and unidirectional delivery strategy for peritendinous anti-adhesion.     

Inside Front Cover: Two‐Dimensional Hexagonally‐Ordered Mesoporous Carbon Nitrides with Tunable Pore Diameter,Surface Area and Nitrogen Content (Adv. Funct. Mater. 5/2008)

Two‐dimensional mesoporous carbon nitride (MCN) with tunable pore diameters have been successfully prepared for the first time using SBA‐15 materials with different pore diameters as templates through a simple polymerization reaction between ethylenediamine (EDA) and carbon tetrachloride (CTC) by a nano hard‐templating approach. The obtained materials have been unambiguously characterized using X‐ray diffraction (XRD), N₂ adsorption, high‐resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high‐resolution scanning electron microscopy (HRSEM), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT‐IR) spectroscopy, and CHN analysis. The results show that the pore diameter of the MCN materials can be easily tuned from 4.2 to 6.4 nm without affecting their structural order. XRD, HRTEM and N₂ adsorption results reveal that the materials are structurally well ordered with a two‐dimensional porous structure, a high surface area and a large pore volume. It is also demonstrated for the first time that the textural parameters such as the specific pore volume, the specific surface area and the pore diameter, and the nitrogen content of the MCN materials can be controlled by the simple adjustment of the EDA to CTC weight ratio. The carbon to nitrogen ratio of the MCN decreases from 4.3 to 3.3 with increasing EDA to CTC weight ratio from 0.3 to 0.9. The optimum EDA to CTC weight ratio required for fabricating the well‐ordered MCN materials with excellent textural parameters and high nitrogen content is around 0.45. The catalytic activity of the materials has been tested in the Friedel‐Crafts acylation of benzene using hexanoyl chloride as the acylating agent. The materials are highly active and show a high conversion and 100 % product selectivity to caprophenone.     

Controlling The Mobility Of Oligonucleotides In The Nanochannels Of Mesoporous Silica

Oligonucleotides used in gene therapy and silencing are fragile compounds that degrade easily in biological environments. Porous biocompatible carrier particles may provide a useful strategy to deliver these therapeutics to their target sites. Development of appropriate delivery vehicles, however, requires a better understanding of the oligonucleotide‐host interactions and the oligonucleotide dynamics inside carrier particles. We investigated template‐free SBA‐15 type mesoporous silica particles and report their loading characteristics with siRNA depending on the surface functionalization of their porous network. We show that the siRNA uptake capability of the particles can be controlled by the composition of the functional groups. Fluorescence recovery after photobleaching measurements revealed size‐dependent mobility of siRNA and double‐stranded DNA oligonucleotides within the functionalized silica particles and provided evidence for the stability of the oligonucleotides inside the pores. Hence, our study demonstrates the potential of mesoporous silica particles as a means for alternative gene delivery in nanomedicine.     

Glutathione‐Activatable and O2/Mn2+‐Evolving Nanocomposite for Highly Efficient and Selective Photodynamic and Gene‐Silencing Dual Therapy

Photodynamic therapy (PDT) has been applied in cancer treatment by converting O₂ into reactive singlet oxygen (¹O₂) to kill cancer cells. However, the effectiveness of PDT is limited by the fact that tumor hypoxia causes an inadequate O₂ supply, and the overexpressed glutathione (GSH) in cancer cells consumes reactive oxygen species. Herein, a multifunctional hybrid system is developed for selective and highly efficient PDT as well as gene‐silencing therapy using a novel GSH‐activatable and O₂/Mn²⁺‐evolving nanocomposite (GAOME NC). This system consists of honeycomb MnO₂ (hMnO₂) nanocarrier loaded with catalase, Ce6, and DNAzyme with folate label, which can specifically deliver payloads into cancer cells. Once endocytosed, hMnO₂ carriers are reduced by the overexpressed GSH to Mn²⁺ ions, resulting in the reduction of GSH level and disintegration of GAOME NC. The released catalases then trigger the breakdown of endogenous H₂O₂ to generate O₂, which is converted by the excited Ce6 into ¹O₂. The self‐sufficiency of O₂ and consumption of GSH effectively enhance the PDT efficacy. Moreover, DNAzyme is freed for gene silencing in the presence of self‐generated Mn²⁺ ions as cofactors. The rational synergy of enhanced PDT and gene‐silencing therapy remarkably improve the in vitro and in vivo therapeutic efficacy of cancers.     

High‐Contrast Electrochromism and Controllable Dissolution of Assembled Prussian Blue/Polymer Nanocomposites

To maintain the momentum and impact of the field, assembled materials systems must increasingly incorporate broad functionality to meet real‐world applications. Here we describe nanocomposite films of specially synthesized inorganic Prussian blue (PB) nanoparticles and linear poly(ethylene imine) (LPEI) that possess the unusual functional combination of high‐performance electrochromism for displays and controllable dissolution for drug delivery. Fabrication using layer‐by‐layer (LBL) assembly was followed by spectroelectrochemical characterization, allowing a full composition determination rarely achieved for LBL films. The electrochromic performance of thick LPEI/PB nanocomposites most relevant to applications surpassed that of inorganic PB films with competitive switching speed and superior contrast. Oxidation beyond the primary electrochromic transition removes nanoparticle ionization and can controllably dissolve the films. Because PB is non‐toxic we suggest this mechanism for controlled in‐vivo drug delivery. The performance and multifunctional quality of these nanocomposites promise a strong impact on flexible displays, electrochromic windows, and even biomedical devices.     

Solid‐State Photovoltaic Thin Films using TiO2, Organic Dyes,and Layer‐by‐Layer Polyelectrolyte Nanocomposites

We report photovoltaic devices consisting of patterned TiO₂, porphyrin dyes, and layer‐by‐layer (LBL) polyelectrolyte multilayer/oligoethylene glycol dicarboxylic acid (OEGDA) composite films. A composite polyelectrolyte LBL/OEGDA film was fabricated by formation of an alternating multilayer of linear polyethyleneimine (LPEI) and polyacrylic acid (PAA), followed by immersion of the LBL film into an OEGDA aqueous solution. The ionic conductivity attained in this LBL LPEI/PAA and OEGDA composite film was approximately 10^–5 S cm^–1 at room temperature and humidity. Investigations of dye‐sensitized photovoltaic devices constructed with the LBL (LPEI/PAA)/OEGDA composite films, TiO₂, and four types of porphyrin dyes resulted in optimization of the dye molecule and its orientation at the interface with the ionically conductive composite. The photocurrent value of photovoltaic devices constructed with the composite LBL/OEGDA film from illumination of a xenon white light source exhibited a nearly 1.5 times enhancement over the device without OEGDA. This enhancement of the photocurrent was due to the high room‐temperature ionic conductivity of the multilayer composite film. Further marked improvements of the photovoltaic performance were achieved by patterning the TiO₂ electrode using polymer stamping as a template for TiO₂ deposition. The device with patterned TiO₂ electrodes exhibited almost 10 times larger conversion efficiencies than a similar device without patterning.     

Multi‐interface cognitive radio for enhanced routing in multi‐hop cellular networks

Multi‐hop cellular network (MCN) is a wireless communication architecture that combines the benefits of conventional single‐hop cellular networks and multi‐hop ad hoc relaying networks. The route selection in MCN depends on the availability of intermediate nodes and their neighborhood connectivity. Cognitive radio (CR) is an emerging communication paradigm that exploits the available radio frequencies opportunistically for the effective utilization of the radio frequency spectrum. The incorporation of CR and mobile ad hoc network routing protocols in MCN could potentially improve the spectrum utilization and the routing performance of MCN. This paper firstly presents the proposed model for the multi‐interface CR mobile node with transceiver synchronization and then investigates its opportunistic spectrum utilization and routing performance in MCN. Copyright © 2015 John Wiley & Sons, Ltd.