|
Elegant and simple to use, the BV-10 offers
precision beveling of micropipette tips between 0.1 and
50Ým. The unique abrasive plate drive system is vibration
free for greater control of the beveling process. Beveling
can be accomplished very rapidly to produce consistent tip
diameters using the techniques as described by Brown and
Flaming, Science, August 1974, Vol. 185.
Intracellular recording electrodes can benefit from beveling
because of 1) a reduction in the tip diameter by creation
of the sharp point on the electrode and 2) a lowered electrical
resistance of the electrode due to the larger cross sectional
area of the lumen. This greatly facilitates penetrating
and holding very small or difficult cells. Microinjection
needles also benefit from beveling by promoting entry into
cells with minimal damage while at the same time enhancing
the flow of material through the needle.
The basic beveling system consists of a stationary pedestal,
optically flat to a half wave (250nm), surface mounted on
a heavy baseplate. This serves as a bearing for an abrasive
coated glass grinding plate, which is also flat to half
a wave. The flat abrasive plate is coupled to a low vibration,
slow-speed motor by means of magnetic fields to provide
a wobble-free flat grinding surface. The abrasive plates
are fabricated with a proprietary process which insures
a consistent abrasive coating.
A 2-stage micromanipulator holds the pipette to be beveled
and permits controlled advancement onto the abrasive surface.
The bevel angle and speed of advancement are adjustable.
A halogen lamp with a gooseneck enhances the beveling operation
by providing sharp illumination of the abrasive plate and
pipette.
The basic system is completed with two abrasive plates of
your choice, a wick with holder (for wet beveling), pedestal
oil, degreasing fluid, and manual.
Two options are available for monitoring the beveling process,
an 80X, stereo microscope and an electrode impedance meter.
Depending on your research application, one or both of these
options may be desirable. For all micropipette applications,
the swing mounted microscope enhances your control of pipette
advancement onto the abrasive plate and allows for viewing
of the beveling operation (scope resolution is not sufficient
for viewing the actual bevel except in the case of very
large tips). For microelectrode applications, the impedance
meter is used to monitor the tip resistance during the beveling
operation. The meter is an analog design, offering three
resistance ranges (0-10, 0-100, 0-500 MOhm). Measurements
are made at 12 Hz to minimize capacitive contributions to
the impedance measured and provide a near-true DC resistance
value. A rapid roll-off is used to reduce 50/60 Hz interference,
allowing operation in a laboratory environment without screening.
|