controlled neural growth on Au/Si substrates

[Joe Strout]

I'm trying to find more information about the controlled outgrowth of 
neurons in culture.  In particular, I wonder

(1) To what extent can the pattern of synaptic connections between cells 
be controlled?  I know that cells can be confined to small (5 um) areas 
on a silicon-based substrate through lithography-controlled deposition of 
binding compounds (such as amines and alkanes).  Using such techniques, 
can cells be kept separated and persuaded to form synapses according to 
the experimenter's plan?

(2) Have substrates been developed which can also serve as a matrix of 
electrodes for the cells growing on them?  I picture a fine grid of 
exposed tips, in contact with the cells or the support solution, which 
can measure or affect the membrane potential where they touch the cells.  
The only reference I can find (citation below) is from 1988:

	The binding characteristics of these silanes also makes
	them compatible with a class of porous gold/silicon
	alloys whose electrical characteristics are suitable
	for constructing arrays of surface electrodes that are
	sensitive to neural activity.

Any more recent information on this technique would be greatly 
appreciated.  Thanks in advance for your help.

,------------------------------------------------------------------.
|    Joseph J. Strout		Department of Neuroscience, UCSD   |
|    jstrout at ucsd.edu		http://sdcc3.ucsd.edu/~jstrout/    |
`------------------------------------------------------------------'

Reference:
Kleinfeld, D., Kahler, K.H., and Hockberger, P.E.  Controlled outgrowth
	of dissociated neurons on patterned substrates.  J. Neuroscience,
	November 1988, 8(11): 4098-4120.