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A simple and rapid method for making carbon fiber microelectrodes
Journal of Neuroscience Methods, 4 (1981) 4352,36 Elsevier/North-Holland Biomedical Press
A SIMPLE AND RAPID METHOD FOR MAKING CARBON FIBER MICROELECTRODES
C.W. Anderson and M.R. Cushman Paul M. Gross Chemical Laboratories, Department of Chemistry, Duke Un i v e rs i t y , Durham, North Carolina 27706 (U.S.A.) Carbon f i b e r microelectrodes have been receiving increased use in the neurosciences in recent years.
Methods of f a b r i c a t i o n have been described
fo r use in recording nerve spikes (Armstrong-James and M i l l a r , 1979; Fox, Armstrong-James and M i l l a r , 1980) and for electrochemically monitorin~ catecholamine release in vivo (Ponchon, Cespuglio, Gonon, Jouvet and Pujol, 1979; also see Lindsay, Kizzort, Justice, Salamone and N e i l l , 1980). The method herein described is r e l a t i v e l y rapid and requires only a pipet p u l l e r and no other elaborate or expensive equipment. high modulus f i b e r s (Union Carbide) were used.
Both low and
There is less l i k e l i h o o d
of the low modulus f i b e r s breaking during manipulation.
The average
response of each type of f i b e r is the same in terms of monitoring catecholamines. The f o l l o w i n g description and times are for the manufacture of f i f t y low modulus microelectrodes.
I) Cut f i f t y
ten centimeter pieces of
number 22 gauge wire, and s t r i p the i n s u l a t i o n back approximately one centimeter at each end (ten minutes).
2) Place a small bundle of fibers
(approximately ten centimeters in length) on white paper;
place a drop
of conducting paint ( e i t h e r s i l v e r conducting paint as used in printed c i r c u i t board construction, or carbon conducting paint used f or mounting scanning electron microscopy samples are suitable) on one end of the stripped wire, and, using f i n e pointed forceps, place the end of a carbon f i b e r in the paint drop and set aside to dry ( t h i r t y minutes). 3) Apply a s l i g h t vacuum to one end of an open-end c a p i l l a r y tube (Kimble, number 34,500) and, allowing the vacuum to pull the f i b e r into the tube, s l i d e the end of the wire into the tube u n t i l i t is stopped by the i n s u l ation on the wire ( f i f t e e n minutes).
4) Apply epoxy at the junction of
the glass and i n s u l a t i o n to make a firm seal ( f i f t e e n minutes).
5) Adjust
pipet p u l l e r heat and solenoid controls to seal t i g h t l y onto f i b e r ard pull (one hour).
(The lower h a l f of the c a p i l l a r y is pulled away, leaving
the f i b e r sealed in the upper portion and protruding from i t . )
6) The
protruding f i b e r is trimmed to the desired length with a small, ~qarp pair of scissors (ten minutes). 0165-0270/81/0000
0000/$02.75 © 1981 Elsevier/North-Holland BiomedicalPress
436
Step 6 is the only d i f f i c u l t
step of the procedure, since the glass is
pulled very t h i n at the f i b e r seal and is e a s i l y broken i f the f i b e r is pulled o f f center while trimming.
The electrodes that do not r e t a i n a
w a t e r - t i g h t seal can be resealed by bringing the t i p of the glass close to a flame u n t i l the glass j u s t glows and reseals.
Examination of the
seal by photomicrography shows that small bubbles are sometimes formed in the glass around the seal, but no evidence of leakage into the seal is found experimentally.
Resealing gives the electrode t i p s much increased
strength and appears to have no e f f e c t on the response to catecholamines (somewhat s u r p r i s i n g since the f i b e r i t s e l f
is sometimes seen to glow).
A f t e r resealing, the f i b e r can be broken o f f level with the glass, and is then ready f o r use.
Although there is some v a r i a t i o n of response between
d i f f e r e n t electrodes, each electrode maintains a stable response through repeated use in v i t r o . REFERENCES Armstrong-James, M. and M i l l a r , J. (1979). Carbon f i b r e microelectrodes. J. Neuroscience Methods I , 279-287. Fox, K., Armstrong-James, M. and M i l l a r , J. (1980). E l e c t r i c a l c h a r a c t e r i s t i c s of carbon f i b r e microelectrodes. J. Neuroscience Methods 3, 37-48. Lindsay, W.S., K i z z o r t , B.L., Justice, J.B., Salamone, J.D. and N e i l l , D.B. (1980). An automated electrochemical method for in vivo monitoring of catecholamine release. J. Neuroscience Methods 2, 373-388. Ponchon, J . L . , Cespuglio, R., Gonon, R., Jouvet, M. and Pujol, J.-F. (1979) Normal pulse polarography with carbon f i b e r electrodes for in v i t r o and in vivo determination of catecholamines, Analyt. Chem., 51, 1483-1486.
(Received August 29th, 1981) (Accepted September 7th, 1981)
A SIMPLE AND RAPID METHOD FOR MAKING CARBON FIBER MICROELECTRODES
C.W. Anderson and M.R. Cushman Paul M. Gross Chemical Laboratories, Department of Chemistry, Duke Un i v e rs i t y , Durham, North Carolina 27706 (U.S.A.) Carbon f i b e r microelectrodes have been receiving increased use in the neurosciences in recent years.
Methods of f a b r i c a t i o n have been described
fo r use in recording nerve spikes (Armstrong-James and M i l l a r , 1979; Fox, Armstrong-James and M i l l a r , 1980) and for electrochemically monitorin~ catecholamine release in vivo (Ponchon, Cespuglio, Gonon, Jouvet and Pujol, 1979; also see Lindsay, Kizzort, Justice, Salamone and N e i l l , 1980). The method herein described is r e l a t i v e l y rapid and requires only a pipet p u l l e r and no other elaborate or expensive equipment. high modulus f i b e r s (Union Carbide) were used.
Both low and
There is less l i k e l i h o o d
of the low modulus f i b e r s breaking during manipulation.
The average
response of each type of f i b e r is the same in terms of monitoring catecholamines. The f o l l o w i n g description and times are for the manufacture of f i f t y low modulus microelectrodes.
I) Cut f i f t y
ten centimeter pieces of
number 22 gauge wire, and s t r i p the i n s u l a t i o n back approximately one centimeter at each end (ten minutes).
2) Place a small bundle of fibers
(approximately ten centimeters in length) on white paper;
place a drop
of conducting paint ( e i t h e r s i l v e r conducting paint as used in printed c i r c u i t board construction, or carbon conducting paint used f or mounting scanning electron microscopy samples are suitable) on one end of the stripped wire, and, using f i n e pointed forceps, place the end of a carbon f i b e r in the paint drop and set aside to dry ( t h i r t y minutes). 3) Apply a s l i g h t vacuum to one end of an open-end c a p i l l a r y tube (Kimble, number 34,500) and, allowing the vacuum to pull the f i b e r into the tube, s l i d e the end of the wire into the tube u n t i l i t is stopped by the i n s u l ation on the wire ( f i f t e e n minutes).
4) Apply epoxy at the junction of
the glass and i n s u l a t i o n to make a firm seal ( f i f t e e n minutes).
5) Adjust
pipet p u l l e r heat and solenoid controls to seal t i g h t l y onto f i b e r ard pull (one hour).
(The lower h a l f of the c a p i l l a r y is pulled away, leaving
the f i b e r sealed in the upper portion and protruding from i t . )
6) The
protruding f i b e r is trimmed to the desired length with a small, ~qarp pair of scissors (ten minutes). 0165-0270/81/0000
0000/$02.75 © 1981 Elsevier/North-Holland BiomedicalPress
436
Step 6 is the only d i f f i c u l t
step of the procedure, since the glass is
pulled very t h i n at the f i b e r seal and is e a s i l y broken i f the f i b e r is pulled o f f center while trimming.
The electrodes that do not r e t a i n a
w a t e r - t i g h t seal can be resealed by bringing the t i p of the glass close to a flame u n t i l the glass j u s t glows and reseals.
Examination of the
seal by photomicrography shows that small bubbles are sometimes formed in the glass around the seal, but no evidence of leakage into the seal is found experimentally.
Resealing gives the electrode t i p s much increased
strength and appears to have no e f f e c t on the response to catecholamines (somewhat s u r p r i s i n g since the f i b e r i t s e l f
is sometimes seen to glow).
A f t e r resealing, the f i b e r can be broken o f f level with the glass, and is then ready f o r use.
Although there is some v a r i a t i o n of response between
d i f f e r e n t electrodes, each electrode maintains a stable response through repeated use in v i t r o . REFERENCES Armstrong-James, M. and M i l l a r , J. (1979). Carbon f i b r e microelectrodes. J. Neuroscience Methods I , 279-287. Fox, K., Armstrong-James, M. and M i l l a r , J. (1980). E l e c t r i c a l c h a r a c t e r i s t i c s of carbon f i b r e microelectrodes. J. Neuroscience Methods 3, 37-48. Lindsay, W.S., K i z z o r t , B.L., Justice, J.B., Salamone, J.D. and N e i l l , D.B. (1980). An automated electrochemical method for in vivo monitoring of catecholamine release. J. Neuroscience Methods 2, 373-388. Ponchon, J . L . , Cespuglio, R., Gonon, R., Jouvet, M. and Pujol, J.-F. (1979) Normal pulse polarography with carbon f i b e r electrodes for in v i t r o and in vivo determination of catecholamines, Analyt. Chem., 51, 1483-1486.
(Received August 29th, 1981) (Accepted September 7th, 1981)