Potential Uses for Nanotechnology in Neuroscience Research and Biomedical Engineering

The following areas have the highest potential for application:

a) Basic Neuroscience

• Exploration of single neurons (see Zygmond et al. 1999, a graduate-level reference for the concepts presented below):

- Develop nanoscale delivery systems for compounds relevant to the nervous system such as neurotransmitters or receptor blockers, etc. These would be used for distributed application to single cells in culture and in situ.

- Develop nanoscale sensors, conductive fibers for stimulating and recording the electrical activity from the surface of single neurons.

Combine delivery and sensing nanofibers with exploration of single neurons in culture, both soma and dendrites, both spread over surface of neuron b) Observation and Study of Growing Cells

• Use sensors and delivery systems to study neuronal development or regenerating fibers in situ. This requires that nanosensors and nano-optical devices be placed in a developing or injured nervous system, either alone or in combination with MEMS or aVLSI devices c) Development

• Monitor growth cones with nano-optical devices

• Provide growth factors with nanoscale delivery systems d) Regeneration

• Study processes as neurons are attempting or failing to regenerate. How do neurons behave as they try to grow? What happens as they encounter obstacles or receptors?

e) Applications in Biomedical Engineering

The following applications assume that nanofibers can be grown or extruded from the tips of microwires in situ:

• Monitor spinal cord injury or brain injury

- use nanofibers to assess the local levels of calcium in injury sites

- use nano delivery systems to provide local steroids to prevent further damage

• Neuroprosthetic devices

- Use nanofibers in conjunction with MEMS or aVLSI devices as delivery systems and stimulating devices for neuroprosthetic devices — make them more efficient.

- Use CPG prosthetic device in conjunction with microwires to stimulate locomotion

- Develop artificial cochlea with more outputs Develop artificial retina with more complex sensors - in combination with aVLSI retinas

Figure F.2 illustrates the positioning of a cochlear implant in the human cochlea (Zygmond et al. 1999). These devices are in current use. The electrode array is inserted through the round window of the cochlea into the fluid-filled space called scala tympani. It likely stimulates the peripheral axons of the primary auditory neurons, which carry messages via the auditory nerve into the brain. It is presently known that the information encoded by the sparsely distributed electrodes is nowhere near that carried by the human cochlea. The device, therefore, is of limited value for hearing-impaired individuals with long-term auditory nerve damage that predates their normal speech learning (Moller 2001). If nanofibers could be deployed from each electrode to better distribute the information, it would likely improve the quality of the device considerably. This would be a relative easy use of the new technology, with easy testing to affirm its usefulness.

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