Various techniques are being developed to enhance the already impressive properties of carbon nanotubes (CNTs) further by combining them with other materials. We have covered plenty of examples in our Spotlights. For instance, encapsulating carbon nanofibers with CNTs transforms cheap commercial carbon nanotubes into highly efficient carbon for electrochemical energy storage applications. Another study demonstrated that the redox properties of iron and iron oxide particles are tunable via encapsulation within CNTs, suggesting that a host-guest interaction between the confined metal particles and CNTs, which is different from that on the outside of the nanotubes. Researchers are still busy trying to understand some of the CNT basics, for instance something as fundamental as 'how do nanotubes grow'? How can their various properties - electronic, transport, or mechanical - be modified? Or how can you make use of CNT's structure and properties to build novel nanotools. A new model demonstrates that sufficiently small liquid metal droplets can be drawn inside a CNT via capillary action.
Scientists consider the exploration of carbon nanotubes (CNTs) for biomedical applications as a field with significant potential, leading to applications where CNTs could act as magnetic nano-heaters, drug-carrier systems and sensors which allow a diagnostic and therapeutic usage on a cellular level. The EU, for instance, has funded a four-year nanotechnology research program that studies the chemical and physical properties of CNTs in order to find mechanisms which can be applied for a biomedical purpose in appropriate medical devices. Studies of their interaction with biological environments (immune response, toxicity, interaction with the single cell) will provide the basis for applying the CNT for imaging (nanoparticles-based contrast agents), sensoring (nanoparticles-based diagnostics) and cancer treatment (hyperthermia, nanotechnology-based targeted drug delivery). A new study that exploits the unique properties of single-walled CNTs (SWCNT) for biomedical purposes shows the use of SWCNTs as an efficient platform for immunotherapeutic applications. Scientists demonstrate the surface area tunability of SWCNT bundles by chemical treatment and its effect on antibody adsorption and subsequent T cell activation. T cells are central players in initiating and maintaining immune responses. An important goal of successful immunotherapy is the stimulation of T cell immune responses against targets of interest such as tumors.
Nanoparticles with at least one dimension of 100 nanometers or less fall in the transitional zone between individual atoms or molecules and the corresponding bulk material, which can drastically modify the physicochemical properties of the material and may generate adverse biological effects in organisms. As the discussion about potentially undesired side effects of engineered nanoparticles heats up, research on toxicological effects of nanomaterials gets increasing attention. Nanotoxicology is quickly being established as a new field, with its major focus on human and animal studies. However, very few studies have been conducted to assess the toxicity of nanomaterials to ecological terrestrial species, particularly plants. So far, the mechanisms of nanoparticle phytotoxicity ? the ability to cause injury to plants ? remain largely unknown and little information on the potential uptake of nanoparticles by plants and their subsequent fate within the food chain is available.
Cells are the basic building blocks of life. The ability to sense and modify intracellular processes is important for, among other things, bettering our understanding of biological processes, developing drugs and evaluating their effectiveness, and modifying cell function. Due to the cell's small size and fragility, probing the cell's interior with high precision is not a simple task. To address this challenge, researchers have developed nanoscale, carbon-based cellular probes ('carbon nanopipettes' or CNP). The CNP consists of a glass capillary lined with a carbon film along its inner surface and terminating with an exposed carbon nanopipe. The probes are fabricated through a process that does not require any assembly and that facilitates quantity fabrication. Depending on controllable process conditions, the carbon tip's diameter may vary from tens to hundreds of nanometers and its length can range from zero to a few micrometers.
Archaeological evidence indicates that ancient Chinese and Babylonian civilizations already were using fingerprints to sign legal documents as early as 1000 BCE. As early as 1880, Dr Henry Faulds, an English physician working in Tokyo, published a letter in the journal Nature suggesting the use of fingerprints for identification purposes. Today, fingerprints are still the primary method of identification of criminals although the techniques for fingerprint detection and enhancement have become hi-tech and involve nanotechnology applications. The most problematic of fingerprints are latent prints that are not readily visible and that require development by chemical and/or physical means. Usually, the choice of the technique for fingerprint development is dependent on the composition of latent fingerprints, on the type of substrate and on the ability of the technique to be applied in sequence in the context of the case. A new review paper describes the current status of nanotechnology-based techniques such as application of metal-containing nanoparticles and nano-structured particles to fingermark detection. It concluds that nanotechnology is likely to play a major role in the future to deliver more selective and more sensitive ways to detect and enhance fingermarks.
The challenge in treating most brain disorders is overcoming the difficulty of delivering therapeutic agents to specific regions of the brain by crossing the blood-brain barrier (BBB). This barrier - a tight seal of endothelial cells that lines the blood vessels in the brain - is a physiological checkpoint that selectively allows the entry of certain molecules from blood circulation into the brain. The problem for scientists is that the BBB does not differentiate what it keeps out. BBB strictly limits transport into the brain through both physical (tight junctions) and metabolic (enzymes) barriers. With very few exceptions, only nonionic and low molecular weight molecules soluble in fat clear the BBB. For instance, alcohol, caffeine, nicotine and antidepressants meet these criteria. However, large molecules needed to deliver drugs do not. The utter scarcity of techniques for brain-specific delivery of therapeutic molecules using non-invasive approaches (like drilling a hole in the skull) has led researchers to increasingly explore the vast potential of nanotechnology toward the diagnosis and treatment of diseases/disorders incurable with present techniques.
Elastomeric (i.e. elastic) proteins are able to withstand significant deformations without rupture before returning to their original state when the stress is removed. Consequently, these proteins confer excellent mechanical properties to many biological tissues and biomaterials. Depending on the role performed by the tissue or biomaterial, elastomeric proteins can behave either as springs or shock absorbers. Recent scientific work in Canada resulted in the engineering of the first artificial chameleon elastomeric proteins that mimic and combine these two different behaviors into one protein. Under the regulation of a molecular regulator, these designer proteins exhibit one of the two distinct mechanical behaviors - spring or shock absorber - which closely mimic the two extreme behaviors observed in naturally occurring elastomeric proteins.
The reduction of linewidth is one of the most important problems in integrated circuit (IC) technology because the speed and performance of computer chips is dictated by the lithographic minimum printable size. In the early 1960s, ICs had a linewidth of about 5 micrometers. Dramatic improvements in optical lithography technology has brought this down to the limits allowed by the wavelength of light that is used in the process. Current state-of-the-art photolithography tools use deep ultraviolet light with wavelengths of 248 and 193 nm, which theoretically allow minimum feature sizes down to 50 nm. But even the shortest UV wavelength currently in use (157 nm) does not provide the resolution required by the ever decreasing feature sizes of state-of-the-art nanomanufacturing processes. Researchers in Israel have been working on the use of laser ablation to write very small features - much smaller than the optical wavelength - on the surface of different materials. They have now demonstrated floating tip nanolithography, a high quality non-contact surface modification with high spatial resolution within a commercial atomic force microscope.