Axon repair: surgical application at a subcellular scale.

Injury to the nervous system is a common occurrence after trauma. Severe cases of injury exact a tremendous personal cost and place a significant healthcare burden on society. Unlike some tissues in the body that exhibit self healing, nerve cells that are injured, particularly those in the brain and spinal cord, are incapable of regenerating circuits by themselves to restore neurological function. In recent years, researchers have begun to explore whether micro/nanoscale tools and materials can be used to address this major challenge in neuromedicine. Efforts in this area have proceeded along two lines. One is the development of new nanoscale tissue scaffold materials to act as conduits and stimulate axon regeneration. The other is the use of novel cellular-scale surgical micro/nanodevices designed to perform surgical microsplicing and the functional repair of severed axons. We discuss results generated by these two approaches and hurdles confronting both strategies.

Isolation of neuronal substructures and precise neural microdissection using a nanocutting device.

We describe a set of microfabricated nanocutting devices with a cutting edge of less than 20 nm radius of curvature that enables high precision microdissection and subcellular isolation of neuronal structures. With these devices, it is possible to isolate functional substructures from neurons in culture such as segments of axons and dendrites, dendritic spines and Nodes of Ranvier. By fine-tuning the mechanical compliance of these devices, they can also act as alternatives to costly laser capture microdissection workstations for harvesting specific neuronal populations from tissue sections for analysis. The small size of the device (1 mm2x100 microm) allows convenient insertion into researcher specific experimental set-ups. Its ease of use and possibility for batch fabrication makes this a highly effective and versatile tool for tissue microdissection and the microanalysis of neuronal function.