The interaction of nanomaterials with cells and lipid bilayers is critical in many applications such as phototherapy, imaging, and drug/gene delivery. These applications require a firm control over nanoparticle–cell interactions, which are mainly dictated by surface properties of nanoparticles. This critical Review presents an understanding of how synthetic and natural chemical moieties on the nanoparticle surface (in addition to nanoparticle shape and size) impact their interaction with lipid bilayers and cells. Challenges for undertaking a systematic study to elucidate nanoparticle–cell interactions are also discussed.
The aim of this review is to explore the fundamental and technological incentive for the molecular design, synthesis, and aggregation behavior of conjugated organic molecules with photo‐electronic activity, and the fabrication of low‐dimensional organic conjugated nanomaterials by self‐assembly techniques. The properties of large oriented nanostructure arrays of organic charge transfer complexes based on conjugated molecules are also discussed. The dimension‐dependent emission properties have been observed, and conductivity, field emission properties, and sensing properties have been studied for the low dimensional nanostructures of nanoparticles, nanowires, nanorods, and nanostructure arrays.
It is now well‐known that the size, shape, and composition of nanomaterials can dramatically affect their physical and chemical properties, and that technologies based on nanoscale materials have the potential to revolutionize fields ranging from catalysis to medicine. Among these materials, anisotropic particles are particularly interesting because the decreased symmetry of such particles often leads to new and unusual chemical and physical behavior. Within this class of particles, triangular Au and Ag nanoprisms stand out due to their structure‐ and environment‐dependent optical features, their anisotropic surface energetics, and the emergence of reliable synthetic methods for producing them in bulk quantities with control over their edge lengths and thickness. This Review will describe a variety of solution‐based methods for synthesizing Au and Ag triangular prismatic structures, and will address and discuss proposed mechanisms for their formation.
Interconnect formation is critical for the assembly and integration of nanocomponents to enable nanoelectronics‐ and nanosystems‐related applications. Recent progress on joining and interconnect formation of key nanomaterials, especially nanowires and carbon nanotubes, into functional circuits and/or prototype devices is reviewed. The nanosoldering technique through nanoscale lead‐free solders is discussed in more detail in this Review. Various strategies of fabricating lead‐free nanosolders and the utilization of the nanosoldering technique to form functional solder joints are reviewed, and related challenges facing the nanosoldering technique are discussed. A perspective is given for using lead‐free nanosolders and the nanosoldering technique for the construction of complex and/or hybrid nanoelectronics and nanosystems.
Microelectrode arrays have unique electrochemical properties such as small capacitive‐charging currents, reduced iR drop, and steady‐state diffusion currents. These properties enable the use of microelectrode arrays and have captured much interest in the field of electrochemistry. Techniques for the fabrication of such arrays are reviewed. The relative features and merits of different techniques are also discussed.
The wide variety of core materials available, coupled with tunable surface properties, make nanoparticles an excellent platform for a broad range of biological and biomedical applications. This Review provides an introduction to nanoparticle–biomolecular interactions as well as recent applications of nanoparticles in biological sensing, delivery, and imaging of live cells and tissues.
Molecular imaging contributes to future personalized medicine dedicated to the treatment of cardiovascular disease, the leading cause of mortality in industrialized countries. Endoscope‐compatible optical imaging techniques would offer a stand‐alone alternative and high spatial resolution validation technique to clinically accepted imaging techniques in the (intravascular) assessment of vulnerable atherosclerotic lesions, which are predisposed to initiate acute clinical events. Efficient optical visualization of molecular epitopes specific for vulnerable atherosclerotic lesions requires targeting of high‐quality optical‐contrast‐enhancing particles. In this review, we provide an overview of both current optical nanoparticles and targeting ligands for optical molecular imaging of atherosclerotic lesions and speculate on their applicability in the clinical setting.
The subtle performance of a virus is closely related to its specific hierarchical structure, which is composed of a rigid shell and transverse, responsive, nanometer‐sized channels. Virus‐like structured colloids are of great interest for their potential applications, for example in drug delivery. Adequate knowledge of the structure and composition control of both colloids and mesoporous materials is significant in the design and synthesis of hierarchically structured colloids to mimic viruses. Some recent developments in the synthesis of composite colloids and mesoporous materials are summarized. Template synthesis is a major tool to control both the macroscopic morphology and microstructures of these composites, in which gel colloids and supramolecular structures from amphiphilic species are used as templates.
In this Progress Report, we discuss our recent achievements in design and synthesis of new functional molecules towards information processing at the molecular level and high‐density information storage. These include: 1) new molecular switches, logic gates, and combinational logic circuits based on molecules and ensembles with photochromic spiropyran units that undergo reversible structural transformation among multistates, in response to external inputs such as light, protons, and metal ions; 2) high‐density information storage, mainly focusing on nanometer‐scale electrical recording based on the conductance transition of organic molecules, and multimode data storage on multiresponsive molecules. Relevant progress and an outlook in this area are also discussed.
This Review presents a discussion of the electromagnetic properties of nanoscale electrical conductors, which are quantum mechanical one‐dimensional systems. Of these, carbon nanotubes are the most technologically advanced example, and are discussed mainly in this paper. The properties of such systems as transmission electron microscopy waveguides for on‐chip signal propagation and also the radiation properties of such systems are discussed. This work is primarily aimed at microwave, nanometer‐wave, and THz electronics. However, the use of nanotubes as antennas in the IR and optical frequency range is not precluded on first principles and remains an open research area.
This report highlights recent progress in the fabrication of vertically aligned carbon nanotubes (VA‐CNTs) on silicon‐based materials. Research into these nanostructured composite materials is spurred by the importance of silicon as a basis for most current devices and the disruptive properties of CNTs. Various CNT attachments methods of covalent and adsorptive nature are critically compared. Selected examples of device applications where the VA‐CNT on silicon assemblies are showing particular promise are discussed. These applications include field emitters, filtration membranes, dry adhesives, sensors and scaffolds for biointerfaces.
Over the past two decades, advances in modern biology and nanotechnology have enabled a rapid development in the design and building of biomimetic functional materials. ATP synthase is one of the most extensively studied molecular machines because it can be used as a rotary motor in the design of novel nanodevices and it can also continuously synthesize ATP in an artificial environment. A lot of research efforts have focused on assembling ATP synthase in biomimetic systems so that a complex cellular process can be constructed in a controllable manner. As we summarize here, layer‐by‐layer assembled microcapsules have proved to be a suitable cellular mimetic structure, which can be applied for engineering active biomimetic systems with a cellular process. An added benefit is that these assembled microcapsules can be used as bioenergy containers and thus ATP supply on demand.
Despite the fact that we live in a 3D world and macroscale engineering is 3D, conventional submillimeter‐scale engineering is inherently 2D. New fabrication and patterning strategies are needed to enable truly 3D‐engineered structures at small size scales. Here, strategies that have been developed over the past two decades that seek to enable such millimeter to nanoscale 3D fabrication and patterning are reviewed. A focus is the strategy of self‐assembly, specifically in a biologically inspired, more deterministic form, known as self‐folding. Self‐folding methods can leverage the strengths of lithography to enable the construction of precisely patterned 3D structures and “smart” components. This self‐assembly approach is compared with other 3D fabrication paradigms, and its advantages and disadvantages are discussed.
The design of hydrogen storage materials is one of the principal challenges that must be met before the development of a hydrogen economy. While hydrogen has a large specific energy, its volumetric energy density is so low as to require development of materials that can store and release it when needed. While much of the research on hydrogen storage focuses on metal hydrides, these materials are currently limited by slow kinetics and energy inefficiency. Nanostructured materials with high surface areas are actively being developed as another option. These materials avoid some of the kinetic and thermodynamic drawbacks of metal hydrides and other reactive methods of storing hydrogen. In this work, progress towards hydrogen storage with nanoporous materials in general and porous organic polymers in particular is critically reviewed. Mechanisms of formation for crosslinked polymers, hypercrosslinked polymers, polymers of intrinsic microporosity, and covalent organic frameworks are discussed. Strategies for controlling hydrogen storage capacity and adsorption enthalpy via manipulation of surface area, pore size, and pore volume are discussed in detail.
The human body is an intricate biochemical–mechanical system, with an exceedingly precise hierarchical organization in which all components work together in harmony across a wide range of dimensions. Many fundamental biological processes take place at surfaces and interfaces (e.g., cell–matrix interactions), and these occur on the nanoscale. For this reason, current health‐related research is actively following a biomimetic approach in learning how to create new biocompatible materials with nanostructured features. The ultimate aim is to reproduce and enhance the natural nanoscale elements present in the human body and to thereby develop new materials with improved biological activities. Progress in this area requires a multidisciplinary effort at the interface of biology, physics, and chemistry. In this Review, the major techniques that have been adopted to yield novel nanostructured versions of familiar biomaterials, focusing particularly on metals, are presented and the way in which nanometric surface cues can beneficially guide biological processes, exerting influence on cellular behavior, is illustrated. Frontispiece adapted from Reference 94 .
The growing demand for analysis of the genomes of many species and cancers, for understanding the role of genetic variation among individuals in disease, and with the ultimate goal of deciphering individual human genomes has led to the development of non‐Sanger reaction‐based technologies towards rapid and inexpensive DNA sequencing. Recent advancements in new DNA sequencing technologies are changing the scientific horizon by dramatically accelerating biological and biomedical research and promising an era of personalized medicine for improved human health. Two single‐molecule sequencing technologies based on fluorescence detection are already in a working state. The newly launched and emerging single‐molecule DNA sequencing approaches are reviewed here. The current challenges of these technologies and potential methods of overcoming these challenges are critically discussed. Further research and development of single‐molecule sequencing will allow researchers to gather nearly error‐free genomic data in a timely and inexpensive manner.
Dip‐pen nanolithography (DPN) is a powerful method to pattern nanostructures on surfaces by the controlled delivery of an “ink” coating the tip of an atomic force microscope upon scanning and contacting with surfaces. The growing interest in the use of nanoparticles as structural and functional elements for the fabrication of nanodevices suggests that the DPN‐stimulated patterning of nanoparticles on surfaces might be a useful technique to assemble hierarchical architectures of nanoparticles that could pave methodologies for functional nanocircuits or nanodevices. This Review presents different methodologies for the nanolithographic patterning of metallic, semiconductor, and metal oxide nanostructures on surfaces. The mechanisms involved in the formation of the nanostructures are discussed and the effects that control the dimensions of the resulting patterns are reviewed. The possible applications of the nanostructures are also addressed.
Colloidal core/shell nanocrystals contain at least two semiconductor materials in an onionlike structure. The possibility to tune the basic optical properties of the core nanocrystals, for example, their fluorescence wavelength, quantum yield, and lifetime, by growing an epitaxial‐type shell of another semiconductor has fueled significant progress on the chemical synthesis of these systems. In such core/shell nanocrystals, the shell provides a physical barrier between the optically active core and the surrounding medium, thus making the nanocrystals less sensitive to environmental changes, surface chemistry, and photo‐oxidation. The shell further provides an efficient passivation of the surface trap states, giving rise to a strongly enhanced fluorescence quantum yield. This effect is a fundamental prerequisite for the use of nanocrystals in applications such as biological labeling and light‐emitting devices, which rely on their emission properties. Focusing on recent advances, this Review discusses the fundamental properties and synthesis methods of core/shell and core/multiple shell structures of II–VI, IV–VI, and III–V semiconductors.
Protein‐based nanomedicine platforms for drug delivery comprise naturally self‐assembled protein subunits of the same protein or a combination of proteins making up a complete system. They are ideal for drug‐delivery platforms due to their biocompatibility and biodegradability coupled with low toxicity. A variety of proteins have been used and characterized for drug‐delivery systems, including the ferritin/apoferritin protein cage, plant‐derived viral capsids, the small Heat shock protein (sHsp) cage, albumin, soy and whey protein, collagen, and gelatin. There are many different types and shapes that have been prepared to deliver drug molecules using protein‐based platforms, including various protein cages, microspheres, nanoparticles, hydrogels, films, minirods, and minipellets. The protein cage is the most newly developed biomaterial for drug delivery and therapeutic applications. The uniform size, multifunctionality, and biodegradability push it to the frontier of drug delivery. In this Review, the recent strategic development of drug delivery is discussed with emphasis on polymer‐based, especially protein‐based, nanomedicine platforms for drug delivery. The advantages and disadvantages are also discussed for each type of protein‐based drug‐delivery system.
