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.
Bionics - a word formed from biology and electronics - has become a quickly expanding research field, exploring ways and materials to bridge the interface between electronics and biology. Basically, there are three levels of biocommunications where electronics and biology could interface: molecular, cellular and skeletal. For any implanted bionic material it is the initial interactions at the biomolecular level that will determine longer term performance. While bionics is often associated with skeletal level enhancements, electronic communication with living cells is of interest with a view to improving the results of tissue engineering or the performance of implants such as bionic ears or eyes. Researchers have worked for more than 20 years on interfacing neurons and silicon devices. Analysis of the electro-physiological activity of neurons could one day enable scientists to develop artificial prostheses for bypassing injured zones and restore brain functionality, or to realize neuro-diagnostic tools for monitoring the reaction of biological neurons to selected chemical species or newly developed drugs. Making another step in this direction, researchers in Europe have now demonstrated the possibility of integrating living neural cells and organic semiconductor thin-films made of a few monolayers of pentacene.
Regenerative medicine is an area in which stem cells hold great promise for overcoming the challenge of limited cell sources for tissue repair. Stem cell research is being pursued in laboratories all over the world in the hope of achieving major medical breakthroughs. Scientists are striving to create therapies that rebuild or replace damaged cells with tissues grown from stem cells and offer hope to people suffering from cancer, diabetes, cardiovascular disease, spinal-cord injuries, and many other disorders. Embryonic stem cells are pluripotent. That means that during normal embryogenesis human embryonic stem cells (hESCs) can differentiate into any of the more than 220 cell types in the adult body. Researchers have now developed a new methodology to enhance the vascular differentiation of hESCs by incorporating growth factor-releasing micro- and nanoparticles in embryoid bodies.
Nanomaterial-based drug-delivery and nanotoxicology are two of the areas that require sophisticated methods and techniques for characterizing, testing and imaging nanoparticulate matter inside the body. Especially the potential risk factors of certain nanomaterials have become a heated topic of discussion recently. Most, if not all, toxicological studies on nanoparticles rely on current methods, practices and terminology as gained and applied in the analysis of micro- and ultrafine particles and mineral fibers. The development of novel imaging techniques that can visualize local populations of nanoparticles at nanometer resolution within the structures of cells - without destroying or damaging the cell - are therefore important. Researchers in the U.S. have now demonstrated that at ultrasonic frequencies, intracellular nanomaterial cause sufficient wave scattering that a probe outside the cell can respond to. This ultrasonic holography technique provides a non-invasive way of looking inside a cell.
The demand for antimicrobial coatings is growing at a fast pace. In the U.S. alone, the market for these products is expected to grow from $175 million in 2005 to over $550 million in 2012. This market is not only driven by the urgent need of hospitals to reduce infections, although it would appear that they need it most: the U.S. Centers for Disease Control and Prevention (CDC) estimates that the infections acquired in hospitals alone affect approximately 2 million persons annually. In the U.S., between 44,000 and 98,000 people die every year from infections they picked up in hospitals. With a growing concern about the role of contaminated surfaces in the spread of infections such as SARS and MRSA, antimicrobial surfaces have become popular in such areas as consumer products, public spaces such as schools and offices, and public transportation. While many conventional antibacterial coatings release their antimicrobials over time (either controlled or uncontrolled) and thereby lose their antimicrobial efficiency, researchers have now developed a unique multifunctional biomimetic material comprised of carbon nanotubes, DNA, and lysozyme that has robust mechanical properties and exhibits excellent long-term antimicrobial activity.
The phenomenon behind many color-based biosensor applications is the excitation of surface plasmons by light - called surface plasmon resonance for planar surfaces or localized surface plasmon resonance (LSPR) for nanoscale metallic structures. Surface plasmon resonance of metallic nanoparticles, in particular gold, has become a popular nanotechnology-enabled technique to build increasingly sensitive and fast biosensors. All the nanostructures used for the biosensing applications have two characteristics: Firstly, they contain certain recognition mechanisms specified to the analyte, for example antibodies or enzymes. Secondly, they are able to generate a distinguishing signal from the analyte and this signal could be generated by the nanostructures themselves or produced by signaling molecules immobilized or contained in the nanostructures. However, proper functionalization remains an issue when it comes to real-world applications, in particular, biological relevant samples such as membrane associated proteins and peptides.
Alzheimer's disease (AD), a brain disorder named for German physician Alois Alzheimer who first described it in 1906, is a disease that destroys brain cells, causing problems with memory, thinking and behavior. Alzheimer's gets worse over time, and it is fatal. It is also the most common form of dementia. The latest estimate is that 26.6 million people were suffering from Alzheimer's disease worldwide in 2006, and this number will rise to 100 million by 2050 - 1 in 85 of the total population. The latest 2008 data for the US alone estimates that 5 million Americans have the disease, with an estimated increase to 11 to 16 million by 2050. Not only does Alzheimer's have no cure, even its cause is unknown (research has led to several theories that are still being investigated). The onset of AD is usually very slow and gradual and, since there is no test for it, there is no clear-cut line between normal age-related changes and warning signs. An absolute diagnosis of AD can only be determined during the examination of brain tissue, which is usually done during an autopsy. A recent report provides an overview of the promises that nanotechnology brings in research on diagnosis and therapy of AD.