Recent Advances in Managing Atherosclerosis via Nanomedicine

Atherosclerosis, driven by chronic inflammation of the arteries and lipid accumulation on the blood vessel wall, underpins many cardiovascular diseases with high mortality rates globally, such as stroke and ischemic heart disease. Engineered bio‐nanomaterials are now under active investigation as carriers of therapeutic and/or imaging agents to atherosclerotic plaques. This Review summarizes the latest bio‐nanomaterial‐based strategies for managing atherosclerosis published over the past five years, a period marked by a rapid surge in preclinical applications of bio‐nanomaterials for imaging and/or treating atherosclerosis. To start, the biomarkers exploited by emerging bio‐nanomaterials for targeting various components of atherosclerotic plaques are outlined. In addition, recent efforts to rationally design and screen for bio‐nanomaterials with the optimal physicochemical properties for targeting plaques are presented. Moreover, the latest preclinical applications of bio‐nanomaterials as carriers of imaging, therapeutic, or theranostic agents to atherosclerotic plaques are discussed. Finally, a mechanistic understanding of the interactions between bio‐nanomaterials and the plaque (“athero–nano” interactions) is suggested, the opportunities and challenges in the clinical translation of bio‐nanomaterials for managing atherosclerosis are discussed, and recent clinical trials for atherosclerotic nanomedicines are introduced.     

Surface modification of hexagonal boron nitride nanomaterials: a review

Hexagonal boron nitride (h-BN) nanomaterials, such as boron nitride nanotubes, boron nitride nanofibers, and boron nitride nanosheets, are among the most promising inorganic nanomaterials in recent years. Their unique properties, including high mechanical stiffness, wide band gap, excellent thermal conductivity, and thermal stability, suggest many potential applications in various engineering fields. In particular, h-BN nanomaterials have been widely used as functional fillers to fabricate high-performance polymer nanocomposites. Like other nanomaterials, prior to their utilization in nanocomposites, surface modification of h-BNs is often necessary in order to prevent their strong tendency to aggregate, and to improve their dispersion and interfacial properties in polymer nanocomposites. However, the high chemical inertness and resistance to oxidation of h-BNs make it rather difficult to functionalize h-BNs. The methods frequently used to oxidize graphitic carbon nanomaterials are not quite successful on h-BNs. Therefore, many novel approaches have been studied to modify h-BN nanostructures. In this review, different surface modification strategies were discussed including various covalent and non-covalent surface modification strategies through wet or dry chemical routes. Meanwhile, the effects of these surface modification methods on the resulting material structures and properties were also reviewed. At last, a number of theoretical studies on the reactivity of h-BNs with different chemical agents have been conducted to explore new surface modification routes, which were also addressed in this review.     

The Role of Surface Groups in Dictating the Chiral-Solvent-Induced Assembly of Carbon Dots into Structures Exhibiting Circularly Polarized Luminescence

Here, the use of achiral nanoparticles and solvent-induced chirality transfer is combined for the making of large structures exhibiting chiroptical properties in the form of circularly polarized luminescence (CPL). The nanoparticles that the authors use are carbon dots (C-Dots) that are known for their bright luminescence and the ability to tune their surface moieties by using different precursors in their synthesis. Here, the result of adding the chiral solvent limonene into an aqueous solution of various C-Dots is explored, differentiated by their surface group. It is shown that only nitrogen-containing C-Dots with amine functional groups see the emergence of a CPL signal and the formation of a large fibrillar assembled structure. The various forces happening in the interface between the C-Dots and the limonene phase and the role of the amine groups in both the chirality transfer interactions and the interactions between C-Dots in the assembly process are discussed, whereas these two processes intertwine with each other. The ability to form fluorescent chiral structures exhibiting CPL from achiral nanoparticles and the understanding of the various interactions in this process are both important to the rationale design of any supramolecular chiral assemblies.     

Supramolecular polymer materials bring restorative heart valve therapy to patients

The functional restoration of natural tissues in a variety of cardiovascular applications is the main objective of Endogenous Tissue Restoration (ETR). The recent progress in the development of biocompatible, biodegradable, and tunable biomaterials with unprecedented properties allow the next steps from laboratory studies to clinical studies. The independent control over mechanical properties and biodegradability provided by the combination of covalent and non-covalent bonds makes supramolecular polymers uniquely qualified for ETR. This paper will provide further details on the mechanism of ETR and will provide a perspective on the preclinical and clinical application of supramolecular polymers for ETR. In addition to various reports on chronic studies in large animal models, three world-first clinical studies are reported, demonstrating the potential of supramolecular technology in bringing ETR to patients.     

Terpyridine-functionalized surfaces: redox-active, switchable, and electroactive nanoarchitecturesgland

Terpyridines represent versatile functional supramolecular building blocks that are easily integrated in numerous devices and can readily modify surfaces. In particular, redox-active complexes with terpyridine ligands have been attached to surfaces, either by covalent or non-covalent interactions, and form highly ordered mono- or multilayer systems, since electronic and charge transport properties are major topics of interest. Their applications in nanoelectronics are a driving force for understanding and enabling the utilization of the supramolecular properties of terpyridines for surface modification. This area of research has received increasing attention during the last decade leading into the supramacromolecular regime. This Progress Report presents an overview of the state-of-the-art of surface modifications utilizing terpyridine systems and highlights main results, as well as modern trends, in this research area.     

Ionic interactions and multilayer structures on self-assembled surfaces of calix[4]resorcinarene

The ionization of a self-assembled monolayer of tetrathiol calix[4]resorcinarene, which is a synthetic host in guest-host recognition phenomena, was investigated. Using surface plasmon resonance measurements, it was found that ionization of the self-assembled surface occurred in water at a pH of approximately 11.5. These ionized surfaces of calix[4]resorcinarene were used to bind ionic guests such as metallic copper ions that were further exploited in the formation of supramolecular ionic assemblies of calix[4]resorcinarene. The structure of the molecular assemblies was characterized using polarization modulation infrared reflection absorption spectroscopy. The use of ionic interactions to attach molecules such as 11-mercapotundecanoic acid to the upper rim of the calix[4]resorcinarene host was also investigated as a method for simple and non-covalent modification of the host cavity.     

Carbon nanomaterials as drug carriers: Real time drug release investigation

The use of carbon nanomaterials in biomedical applications and the cytotoxicity of these materials have been areas of great interest during the last decade. In vitro drug load and release, as well as in vivo animal tests, have been carried out using carbon nanomaterials. However, no comparison studies on the drug load and the release of different carbon nanomaterials have been reported. Here, we report on a real time investigation of the drug release of carbon black (CB) nanoparticles, carbon nanotubes (CNTs) and graphene oxide (GO), using rhodamine B (RB) as a model of drug. The binding of RB to the nanomaterials were characterized by FTIR and UV–vis. The mass loading capacities of these nanomaterials were also studied, showing that GO had the highest capacity. The real time drug release experiment indicated different accumulative release modes of these nanomaterials at different pH values, due to their different binding modes with RB, which is also discussed as being the reason for the mechanism differences. Moreover, the comparison of the drug release capacity of CNT–RB and f-CNT–RB (functionalized-CNT–RB) indicated an influence of hydrogen bonds in both drug loading and release, as the hydrogen bonds increased the loading capacity of the carbon nanotube after acid treatment and changed the drug release mechanism at pH 7.4. Thus, here we identified the drug release modes of the different carbon nanomaterials. The results of the influence of functional groups and hydrogen bonds point also out a potential way of controlling the drug release behavior of carbon nanomaterials by surface modification.     

细菌纤维素基纳米生物材料在储能领域的应用

细菌纤维素(Bacterial Cellulose, BC)是由微生物发酵获得的具有纳米尺寸的聚合物生物材料, 具有比表面积大、机械强度高、持水能力强、化学稳定性好及环境友好等特质, 可用于制备三维纳米碳材料的前驱体或支撑其他功能材料的柔性骨架。本文介绍了基于BC制备的各种碳纳米纤维(Carbon Nanofiber, CNF)及其复合材料, 包括掺杂CNF、CNF/金属氧化物、CNF/导电聚合物等材料。描述了这些材料在超级电容器中的应用, 关注BC用于可弯曲电极的设计和制备; 进一步阐述了当前BC应用于能源存储领域所面临的挑战和机遇, 并对其未来发展包括在高性能二次电池方面的应用等进行了展望。     

A recyclable supramolecular membrane for size-selective separation of nanoparticles

Most practical materials are held together by covalent bonds, which are irreversible. Materials based on noncovalent interactions can undergo reversible self-assembly, which offers advantages in terms of fabrication, processing and recyclability, but the majority of noncovalent systems are too fragile to be competitive with covalent materials for practical applications, despite significant attempts to develop robust noncovalent arrays. Here, we report nanostructured supramolecular membranes prepared from fibrous assemblies in water. The membranes are robust due to strong hydrophobic interactions, allowing their application in the size-selective separation of both metal and semiconductor nanoparticles. A thin (12 μm) membrane is used for filtration (～5 nm cutoff), and a thicker (45 μm) membrane allows for size-selective chromatography in the sub-5 nm domain. Unlike conventional membranes, our supramolecular membranes can be disassembled using organic solvent, cleaned, reassembled and reused multiple times.     

Synthesis of fluorescent composite macromolecules by using organic/inorganic assemblies as structural units

A synthetic pathway is introduced to construct fluorescent composite macromolecules with supramolecular assemblies as structural units. The supramolecular assembly that contains polymerizable groups is used as a starting "monomer." The supramolecular assembly is composed of nanoparticle core of II - IV group semiconductor and organic ammonium shell. Polymerization of the assemblies yields soluble composite macromolecules. Light scattering data show that the macromolecule has an average size of about 310 nm in diameter in chloroform; AFM image illustrates that the macromolecule has an average diameter of 120 nm and an average height of 35 nm on a mica surface and photoluminescent spectra reveal that the macromolecule performs an extraordinary enhancement in fluorescence intensity of the semiconductor nanoparticles. These observations suggest that construction of macromolecules with supramolecular assembly as starting monomer may produce generations of materials with novel properties.     

The development of carbon dots: From the perspective of materials chemistry

The advance of materials chemistry has influenced significantly the lifestyle of mankind. By virtue of their fascinating physicochemical nature – including ultrasmall size (<10 nm), rich functional groups, fluorescence, chemical stability, biocompatibility, and nontoxicity – carbon dots have been acclaimed as another epoch-making carbon-based nanomaterial following on from fullerene, nanotubes, and graphene. However, the field of carbon dot-based materials chemistry remains incomplete because of their wide structural diversity, meaning that much fundamental knowledge still needs to be uncovered. Herein, this review proposed several novel viewpoints in term of carbon dot-based material chemistry, including the development history, classification, design principle and applications of carbon dots-based materials. Finally, several sound prospects in this fascinating filed are also given.     

Preparation and mechanical characterization of laser ablated single-walled carbon-nanotubes/polyurethane nanocomposite microbeams

We report on the preparation of nanocomposites consisting of laser synthesized single-walled carbon nanotubes (C-SWNTs) reinforcing a polyurethane. Prior to their incorporation into the polymer matrix, the C-SWNTs were purified, and characterized by means of various techniques. The purification in nitric acid added carboxylic groups to the C-SWNTs. A procedure to properly disperse the nanomaterials in the polymer was developed involving high shear mixing using a three-roll mill and a non-covalent functionalization of the nanotubes by zinc protoporphyrin IX molecule. The incorporation of the C-SWNTs into the resin led to an increase of the viscosity and the apparition of a slight shear-thinning behavior. A further increase of the shear-thinning behavior using fumed silica particles enabled the direct-write fabrication of microbeams. Mechanical characterization revealed significant increase in both strength (by ∼64%) and modulus (by more than 15 times). These mechanical enhancements are believed to be a consequence of the successful covalent and the non-covalent functionalizations of the nanotubes.     

Interparticle Forces Underlying Nanoparticle Self‐Assemblies

Studies on the self‐assembly of nanoparticles have been a hot topic in nanotechnology for decades and still remain relevant for the present and future due to their tunable collective properties as well as their remarkable applications to a wide range of fields. The novel properties of nanoparticle assemblies arise from their internal interactions and assemblies with the desired architecture key to constructing novel nanodevices. Therefore, a comprehensive understanding of the interparticle forces of nanoparticle self‐assemblies is a pre‐requisite to the design and control of the assembly processes, so as to fabricate the ideal nanomaterial and nanoproducts. Here, different categories of interparticle forces are classified and discussed according to their origins, behaviors and functions during the assembly processes, and the induced collective properties of the corresponding nanoparticle assemblies. Common interparticle forces, such as van der Waals forces, electrostatic interactions, electromagnetic dipole‐dipole interactions, hydrogen bonds, solvophonic interactions, and depletion interactions are discussed in detail. In addition, new categories of assembly principles are summarized and introduced. These are termed template‐mediated interactions and shape‐complementary interactions. A deep understanding of the interactions inside self‐assembled nanoparticles, and a broader perspective for the future synthesis and fabrication of these promising nanomaterials is provided.     

Single functional group interactions with individual carbon nanotubes

Carbon nanotubes display a consummate blend of materials properties that affect applications ranging from nanoelectronic circuits and biosensors to field emitters and membranes. These applications use the non-covalent interactions between the nanotubes and chemical functionalities, often involving a few molecules at a time. Despite their wide use, we still lack a fundamental understanding and molecular-level control of these interactions. We have used chemical force microscopy to measure the strength of the interactions of single chemical functional groups with the sidewalls of vapour-grown individual single-walled carbon nanotubes. Surprisingly, the interaction strength does not follow conventional trends of increasing polarity or hydrophobicity, and instead reflects the complex electronic interactions between the nanotube and the functional group. Ab initio calculations confirm the observed trends and predict binding force distributions for a single molecular contact that match the experimental results. Our analysis also reveals the important role of molecular linkage dynamics in determining interaction strength at the single functional group level.     

Programmable Nano–Bio Interfaces for Functional Biointegrated Devices

A large amount of evidence has demonstrated the revolutionary role of nanosystems in the screening and shielding of biological systems. The explosive development of interfacing bioentities with programmable nanomaterials has conveyed the intriguing concept of nano–bio interfaces. Here, recent advances in functional biointegrated devices through the precise programming of nano–bio interactions are outlined, especially with regard to the rational assembly of constituent nanomaterials on multiple dimension scales (e.g., nanoparticles, nanowires, layered nanomaterials, and 3D‐architectured nanomaterials), in order to leverage their respective intrinsic merits for different functions. Emerging nanotechnological strategies at nano–bio interfaces are also highlighted, such as multimodal diagnosis or “theragnostics”, synergistic and sequential therapeutics delivery, and stretchable and flexible nanoelectronic devices, and their implementation into a broad range of biointegrated devices (e.g., implantable, minimally invasive, and wearable devices). When utilized as functional modules of biointegrated devices, these programmable nano–bio interfaces will open up a new chapter for precision nanomedicine.     

Large‐Area 3D Hierarchical Superstructures Assembled from Colloidal Nanoparticles

Assembling nanosized building blocks into macroscopic 3D complex structures is challenging. Here, nanosized metal and semiconductor building blocks with a variety of sizes and shapes (spheres, stars, and rods) are successfully assembled into a broad range of hierarchical (nanometer to micrometer) assemblies of functional materials in centimeter size using butterfly wings as templates. This is achieved by the introduction of steric hindrance to the assembly process, which compensates for attraction from the environmentally sensitive hydrogen bonds and prevents the aggregation of nanosized building blocks. Of these materials, Au nanostar assemblies show a superior enhancement in surface‐enhanced Raman scattering (SERS) performance (rhodamine 6G, 1506 cm^?1) under 532, 633, and 780 nm excitation—this is 3.1–4.4, 3.6–3.9, and 2.9–47.3 folds surpassing Au nanosphere assemblies and commercial SERS substrates (Q‐SERS), respectively. This method provides a versatile route for the assembly of various nanosized building blocks into different 3D superstructures and for the construction of hybrid nanomaterials and nanocomposites.     

Generation of protein lattices by fusing proteins with matching rotational symmetry

The self-assembly of supramolecular structures that are ordered on the nanometre scale is a key objective in nanotechnology. DNA and peptide nanotechnologies have produced various two- and three-dimensional structures, but protein molecules have been underexploited in this area of research. Here we show that the genetic fusion of subunits from protein assemblies that have matching rotational symmetry generates species that can self-assemble into well-ordered, pre-determined one- and two-dimensional arrays that are stabilized by extensive intermolecular interactions. This new class of supramolecular structure provides a way to manufacture biomaterials with diverse structural and functional properties.     

Strong Electrochemiluminescence Emission from Oxidized Multiwalled Carbon Nanotubes

Carbon nanotubes (CNTs) as well‐known nanomaterials are extensively studied and widely applied in various fields. Nitric acid (HNO₃) is often used to treat CNTs for purification purposes and preparing oxidized CNTs for various applications. However, too little attention is paid to investigating the effect of HNO₃ treatment on the optical properties of CNTs. In this work, it is observed for the first time that HNO₃‐oxidized multiwalled carbon nanotubes (ox‐MWCNTs) have strong electrochemiluminescence (ECL) activity, which enables ox‐MWCNTs to become new and good ECL carbon nanomaterials after carbon quantum dots (CQDs) and graphene quantum dots (GQDs). Various characterization technologies, such as transmission electron microscope (TEM), X‐ray photoelectron spectroscopy (XPS), and Raman spectroscopy, are used to reveal the relationship between ECL activity and surface states. The ECL behaviors of ox‐MWCNTs are investigated in detail and a possible ECL mechanism is proposed. Finally, the new ECL nanomaterials of ox‐MWCNTs are envisioned to have promising applications in sensitive ECL sensing and in the study of CNT‐based catalysts.     

Supramolecular Two-Dimensional Systems and Their Biological Applications

Various biological systems rely on the supramolecular assembly of biomolecules through noncovalent bonds for performing sophisticated functions. In particular, cell membranes, which are 2D structures in biological systems, have various characteristics such as a large surface, flexibility, and molecule-recognition ability. Supramolecular 2D materials based on biological systems provide a novel perspective for the development of functional 2D materials. The physical and chemical properties of 2D structures, attributed to their large surface area, can enhance the sensitivity of the detection of target molecules, molecular loading, and bioconjugation efficiency, suggesting the potential utility of functional 2D materials as candidates for biological systems. Although several types of studies on supramolecular 2D materials have been reported, supramolecular biofunctional 2D materials have not been reviewed previously. In this regard, the current advances in 2D material development using molecular assembly are discussed with respect to the rational design of self-assembling aromatic amphiphiles, the formation of 2D structures, and the biological applications of functional 2D materials.     

Interplay of Depletion Forces and Biomolecular Recognition in the Hierarchical Assembly of Supramolecular Tubes

Crowding effects have a profound impact on the hierarchical organization of cellular architectures. In the fields of systems chemistry and soft matter, this effect has not received much attention so far. Here, it is explored how poly(ethylene glycol) (PEG) as a crowding agent invokes depletion forces that act on synthetic supramolecular tubes. Hence, supramolecular tubes are pushed from their random orientation into hierarchically assembled bundles due to the PEG-induced crowded environment. The resulting morphology of formed bundled architectures can be tuned by the concentrations of both the supramolecular tubes and the PEG. The introduction of biotin groups at the surface of the tubes allows the engineering of biotin–streptavidin crosslinks between them. The order of introducing PEG and streptavidin in the system further affects the formed hierarchical assemblies, as well as their resistance toward dilution. The strategy described here provides a new route to establish hierarchically organized supramolecular architectures, combining crowding and specific biomolecular interactions, which shows the potential for controlling the structure of supramolecular materials and other soft matter systems.