Journal of nanoneuroscience最新文献

We use an Atomic Force Microscope based single molecule measurements to evaluate the activation free energy in the interaction of SNARE proteins syntaxin 1A, SNAP25B and synaptobrevin 2 which regulate intracellular fusion of vesicles with target membranes. The dissociation rate of the binary syntaxin-synaptobrevin and the ternary syntaxin-SNAP25B-synaptobrevin complex was measured from the rupture force distribution as a function of the rate of applied force. The temperature dependence of the spontaneous dissociation rate was used to obtain the activation energy to the transition state of 19.8 +/- 3.5 kcal/mol = 33 +/- 6 k(B)T and 25.7 +/- 3.0 kcal/mol = 43 +/- 5 k(B)T for the binary and ternary complex, respectively. They are consistent with those measured previously for the ternary complex in lipid membranes and are of order expected for bilayer fusion and pore formation. The DeltaG was 12.4-16.6 kcal/mol = 21-28 k(B)T and 13.8-18.0 kcal/mol = 23-30 k(B)T for the binary and ternary complex, respectively. The ternary complex was more stable by 1.4 kcal/mol = 2.3 k(B)T, consistent with the spontaneous dissociation rates. The higher adhesion energies and smaller molecular extensions measured with SNAP25B point to its possible unique and important physiological role in tethering/docking the vesicle in closer proximity to the plasma membrane and increasing the probability for fusion completion.

Carbon nanotubes, owing to their electrical, chemical, mechanical, and thermal properties, are one of the most promising nanomaterials for the electronics, computer, and aerospace industries. More recently, these unique materials are finding their niche in neuroscience. Here, we discuss the use of carbon nanotubes as scaffolds for neuronal growth. The chemical properties of carbon nanotubes can be systematically varied by attaching different functional groups. Such functionalized carbon nanotubes can be used to control the outgrowth and branching pattern of neuronal processes. We also discuss electrical interactions between neurons and carbon nanotubes. The electrical properties of nanotubes can provide a mechanism to monitor or stimulate neurons through the scaffold itself. The ease of which carbon nanotubes can be patterned makes them attractive for studying the organization of neural networks and has the potential to develop new devices for neural prosthesis. We note that additional toxicity studies of carbon nanotubes are necessary so that exposure guidelines and safety regulations can be set.

Alzheimer's disease (AD) is a devastating neuro-degenerative disorder characterized by the progressive and irreversible loss of memory followed by complete dementia. Despite the disease's high prevalence and great economic and social burden, an explicative etiology or viable cure is not available. Great effort has been made to better understand the disease's pathogenesis, and to develop more effective therapeutic agents. However, success is greatly hampered by the presence of the blood-brain barrier that limits a large number of potential therapeutics from entering the brain. Nanoparticle-mediated drug delivery is one of the few valuable tools for overcoming this impediment and its application as a potential AD treatment shows promise. In this review, the current studies on nanoparticle delivery of chelation agents as possible therapeutics for AD are discussed because several metals are found excessive in the AD brain and may play a role in the disease development. Specifically, a novel approach involving transport of iron chelation agents into and out of the brain by nanoparticles is highlighted. This approach may provide a safer and more effective means of simultaneously reducing several toxic metals in the AD brain. It may also provide insights into the mechanisms of AD pathophysiology, and prove useful in treating other iron-associated neurodegenerative diseases such as Friedreich's ataxia, Parkinson's disease, Huntington's disease and Hallervorden-Spatz Syndrome. It is important to note that the use of nanoparticle-mediated transport to facilitate toxicant excretion from diseased sites in the body may advance nanoparticle technology, which is currently focused on targeted drug delivery for disease prevention and treatment. The application of nanoparticle-mediated drug transport in the treatment of AD is at its very early stages of development and, therefore, more studies are warranted.