WPI MF200 User manual
Instrumenting scientific ideas
WORLD
PRECISION
INSTRUMENTS
MF200
Microforge with 40× long working distance objective
Serial No._____________________
www.wpiinc.com
INSTRUCTION MANUAL
030716
MF200
World Precision Instruments i
Copyright © 2016 by World Precision Instruments, Inc. All rights reserved. No part of this publication
may be reproduced or translated into any language, in any form, without prior written permission of
World Precision Instruments, Inc.
CONTENTS
ABOUT THIS MANUAL ................................................................................................................... 1
INTRODUCTION .............................................................................................................................. 2
INSTRUMENT DESCRIPTION ........................................................................................................ 3
Parts List...................................................................................................................................... 3
Unpacking................................................................................................................................... 3
Description ................................................................................................................................. 4
Optics ..................................................................................................................................... 4
Positioning and Focus ........................................................................................................ 5
Heating Filaments................................................................................................................ 5
Microscope ........................................................................................................................... 6
Power Controller (Control Unit)....................................................................................... 6
OPERATING INSTRUCTIONS......................................................................................................... 8
Setting up the MF200 .............................................................................................................. 8
Mounting the LWD to the Microscope........................................................................... 8
Mounting the Filament Adjustment Assembly to the Microscope.......................... 9
Positioning the Micropipette Holder ............................................................................10
Mounting the Heating Filament.....................................................................................10
Basic Operations for Using the MF200 .............................................................................11
Applications..............................................................................................................................14
Fire Polishing the Patch Clamp Pipette........................................................................14
Fire Polishing a Pipette Tip .............................................................................................15
Tip Size Reduction.............................................................................................................16
Fire Polishing Large Bore Pipettes ...............................................................................16
Tip Reduction of Large Bore Pipettes .........................................................................17
Reducing Overall Filament Expansion..........................................................................17
Microforging Beveled Injection Pipettes......................................................................17
INSTRUMENT MAINTENANCE....................................................................................................19
ACCESSORIES.................................................................................................................................19
SPECIFICATIONS............................................................................................................................20
APPENDIX A: MICROSCOPE OBJECTIVE INFORMATION ......................................................20
INDEX...............................................................................................................................................21
DECLARATION OF CONFORMITY ..............................................................................................22
WARRANTY .....................................................................................................................................23
Claims and Returns ................................................................................................................23
Repairs.......................................................................................................................................23
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MF200
World Precision Instruments 1
ABOUT THIS MANUAL
The following symbols are used in this guide:
This symbol indicates a CAUTION. Cautions warn against actions that can cause
damage to equipment. Please read these carefully.
This symbol indicates a WARNING. Warnings alert you to actions that can cause
personal injury or pose a physical threat. Please read these carefully.
NOTES and TIPS contain helpful information.
Fig. 1—MF200 System
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INTRODUCTION
The MF200 Microforge is a versatile device designed specically for the fabrication of
glass micropipettes and other related tools. Originally designed by Dr. Ming Li of the
Department of Pharmacology, University of South Alabama, it has been extensively
improved to provide greater accuracy and ease of use. It is simple, durable and
reliable. Ideal for patch pipette polishing, it can also be used for other fabrication
procedures such as pipette tip size reduction, contact stretching to sharpen large
bore pipettes, carbon ber electrode sealing and the production of a variety of pipette
congurations including those for in vitro fertilization. Its simplicity and ease of use
result from two key features:
• Utilization of a microscope to manipulate the pipette
• Unique design of the lament holder that permits attachment of the heating
element directly to the microscope objective.
These features enable precise fabrication specications to be easily met.
CAUTION: The Microforge Control Unit (power) and the heating laments have
been carefully matched to provide rapid lament response at optimum heat
intensity. Use of either of these components with alternate power units or
heating laments may result in severe damage to any or all of these components.
Fig. 2—MF200 Startup Kit
MF200
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INSTRUMENT DESCRIPTION
Parts List
After unpacking, verify that there is no visible damage to the instrument. Verify that all
items are included:
MF200-1/2 Complete Microforge 110V/220V (includes microscope):
(1) W30S Microscope (See W30S Instruction Manual included for set-up, assembly
and operating instructions.)
(1) MF200 Microforge (See parts list below.)
MF200-M1/M2 Microforge 110V/220V (microscope not included):
(1) MF200 Microforge Control Unit
(1) 14470 AC to 12VDC converter with power cord (USA only)
(1) Man-MF200 MF200 Instruction Manual
(1) 75006 MF-200 Start-Up Kit, including:
(1) 800292 40× long-working distance objective
(1) 75050 Lucite and glass pipette holder
(1) 75090 Filament Adjustment Assembly for 40× and 25× LWD objectives
(1) 75040 One pair of heating lament connecting cables
(1) 800003 3/16 hex wrench
(1) MF200-H2 H2 Heating Filament
(1) MF200-H3 H3 Heating Filament
(1) MF200-H4 H4 Heating Filament
(1) 503513 Eyepiece with Linear Reticle
(1) 300497 Spacer Ring for mounting on the 10X objective with 22mm OD
(1) 75027 Spacer Ring for mounting on the 10X objective with 21mm OD
NOTE: The spacer ring (WPI #300497 may not be necessary for objectives with
larger outside diameters. It is use with objectives smaller than 23.0mm.
Unpacking
Upon receipt of this instrument, make a thorough inspection of the contents and
check for possible damage. Missing cartons or obvious damage to cartons should be
noted on the delivery receipt before signing. Concealed damage should be reported
at once to the carrier and an inspection requested. Please read the section entitled
“Claims and Returns” on page 23 of this manual. Please contact WPI Customer
Returns: Do not return any goods to WPI without obtaining prior approval (RMA
# required) and instructions from WPI’s Returns Department. Goods returned
(unauthorized) by collect freight may be refused. If a return shipment is necessary,
use the original container, if possible. If the original container is not available, use a
suitable substitute that is rigid and of adequate size. Wrap the instrument in paper or
plastic surrounded with at least 100mm (four inches) of shock absorbing material. For
further details, please read the section entitled “Claims and Returns” on page 23 of
this manual.
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Description
The complete MF200-1 (110V) and MF200-2 (220V) systems include both the
Microforge and matched microscope (WPI Model W30S); the MF200–M1 (110V) and
MF200-M2 (220V) include the Microforge only.
Optics
The MF200 is the only commercial microforge that includes a 40X long-working
distance objective (LWD). This LWD objective is the most powerful currently available
on any commercially produced microforge. Its 40X magnication is essential when
polishing pipettes as small as half a micron (0.5mm) in diameter. A linear eyepiece
reticle is provided with this system for measureing pipette tip dimensions. An optional
angular reticle is available. See page 19 for details. Optional accessories (including
a 25X LWD objective for the W30S microscope) further expand the MF200 system
functionality.
Fig. 3— MF200 System (not shown: 12 V DC power converter for Microforge Control
Unit).
MF200
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Positioning and Focus
Finding and moving the pipette tip under the microscope objective is simple. With a
conventional microforge, it is dicult and time-consuming to position both the heating
lament and pipette in the viewing area using independent micromanipulators.
A unique feature of the MF200 is the heating lament, inserted into the Filament
Adjustment Assembly, which is directly attached to the microscope’s objective
and (using the horizontal and vertical adjustment knobs of the assembly) can be
easily maneuvered to any position within the viewing area. Once the correct focus
is obtained, the lament will remain xed and within focus, and attention can be
turned towards positioning the pipette that rests on the microscope stage. The X-Y-Z
movements of the microscope stage adjustment controls its position relative to the
heating lament. This design makes the positioning and microforging of pipettes
extremely easy. The stage of the MF200 W30S microscope has a high quality rail
that ensures precise, smooth and stable control of the pipette’s movement. The
MF200 system conguration eliminates the need and expense of an additional
micromanipulator to control pipette movement.
Heating lament
Horizontal
adjustment
Vertical adjustment
Filament
Clamp
10X
objective
Ring
Mounting
screw
Fig. 4—Filament Adjustment Assembly
Heating Filaments
Low heat capacity and low thermal expansion of the laments are key design features
of the MF200 Microforge. The low heat capacity of the lament allows it to reach
re-polishing temperatures without excessive heat. This permits the pipette tip to be
brought close to the lament during polishing without fear of collapsing the pipette tip
and eliminates the need for an auxiliary air cooling system. The low thermal expansion
6 World Precision Instruments
characteristic of the lament ensures minimal displacement of the lament during
heating. This feature takes much of the guesswork out of tip placement in relation to
the lament. Three functionally distinct heating laments are provided to meet diverse
application needs.
Table 1: Filaments
Filament Gauge Material Application
H2 0.004” Platinum/iridium wire Large gauge, long: can be formed
into a variety of shapes (reformed)
for fabrication of pipettes up
through the 100-200mm range.
Reforming the lament can result
in a greater heated surface area
to present to the pipette tip. For
large pipettes, it is best used with
the 10X standard objective on the
model W30S microscope (optional
Filament Adjustment Assembly
required) or the optional 25X LWD
objective.
H3 0.002” Platinum/iridium wire Medium gauge, short: for polish-
ing patch clamp pipettes or larger
pipettes up to 3-5mm.
H4 0.001” Platinum/iridium wire Small gauge: for polishing patch
clamp pipettes.
Microscope
The microforge has been matched with WPI research-grade microscope model W30S
to provide an uncomplicated and complete system with excellent performance. The
Filament Adjustment Assembly supplied with the microforge has been designed to
t both the 40X LWD objective (included) and the optional 25X LWD objective for the
W30S microscope. The Filament Adjustment Assembly will t most other microscopes
with a focal length of 160mm. The optional Filament Adjustment Assembly for the 10X
objective is, however, designed specically to t the model W30S 10X objective.
Power Controller (Control Unit)
The MF200 is powered by a 12VDC adapter to supply power to the Control Unit. The
Control Unit is compact and lightweight, and its output power is electrically stable and
reproducible. Fluctuations in the mains voltage input will not aect the output to the
lament. This ensures the same polishing results day to day at the same settings. A
0.5"
.004 wire
Filament MF200-H2
0.18"
.001 wire
Filament MF200-H4
0.25"
.002 wire
Filament MF200-H3
MF200
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push-button polish switch on the Control Unit turns the heating lament on and o.
An optional foot switch is available for complex re polishing. Use of the optional
foot switch leaves the hands free to move the pipette and control the variable heat
adjustment on the Control Unit.
FILAMENT
OUTPUT
70
60
80
50
40
30
20
90
100
POWER
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LARG E SMALL
ON
Forge
On
OFF
MF-200
HEAT
Polish
-+
+12 VDC IN
FOOT
SWITCH
OPTION
FILAMENT
POWER
M
I
C
R
O
F
O
R
G
E
12VDC input
Set power level for
filament to be used:
LOW (or LARGE), HIGH
(or SMALL)
Input for optional
foot switch
Rocker
switch lights
up when
power is on
Connectors
for cables to
filament
Heat dial
control
varies
power to
heating
element
Polish button sends
current to the filament
Fig. 5—Microforge Control Unit
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OPERATING INSTRUCTIONS
Setting up the MF200
Four steps are required to set up the MF200. First, mount the LWD to the microscope.
Then, mount the Filament Adjustment Assembly to the microscope. Next, position the
micropipette holder on the microscope stage. Finally, install the heating lament.
Mounting the LWD to the Microscope
1. Mount the long-working distance (LWD) objective to an available position on the
microscope.
2. Lower the microscope stage as far it will go.
3. When using the 10X LWD, slide the Spacer Ring (WPI #300497) over the tip of the
objective as shown in Figure 6. This Filament Adjustment Assembly slides over the
Spacer Ring for a snug t.
Fig. 6—Slide the Spacing Ring over the objective tip
NOTE: The spacer ring (WPI #300497) may not be necessary for objectives with larger
outside diameters. It is use with objectives smaller than 23.0mm. To determine if you need
a spacer, measure the outside diameter of your objective and refer to the chart below.
Outside Diameter of
Objective Spacer Required
Objectives
Aected
21.0mm WPI #75027 Some 10X
22.0mm WPI #300497 Some 10X
23.0mm none Some 10X
23.5mm none 40X LWD
MF200
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Mounting the Filament Adjustment Assembly to the
Microscope
1. Using the 3/16 hex wrench provided, loosen the mounting screw on the Filament
Adjustment Assembly to open the ring so that it will t comfortably over the
objective and the Spacing Ring (Fig. 7).
2. Swing the objective to an outside position. It should not pointed directly down.
Mount the Filament Adjustment Assembly onto the objective by carefully placing
the ring around the objective and then sliding it up until it stops.
3. While maintaining the Filament Adjustment Assembly in position on the
objective, slowly swing the objective down into the viewing position. Once in
place, position the horizontal adjustment slider to the left of the microscope
objective and parallel to the long edge of the microscope stage (Fig. 7). With the
3/16 hex wrench, tighten the mounting screw on the ring to secure the Filament
Adjustment Assembly to the objective.
Filament Clamp
Horizontal
Adjustment Slider Spacing Ring
Mounting Screw
3/16" Hex Wrench
Fig. 7—Mounting screw and proper orientation of the lament adjustment assembly
CAUTION: Do not overtighten the mounting screw. Too much force can
damage the objective.
NOTE: The lament clamp and base plate attached to the vertical lament
adjustment is angled slightly inward. This is normal. Do not attempt to straighten
it. This angle facilitates viewing of the lament under the microscope.
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4. Connect the appropriate plug from the AC/DC converter into the 12VDC
receptacle on the Microforge Control Unit, and then plug the converter into a wall
outlet.
Positioning the Micropipette Holder
Position the Pipette Holder on the microscope stage as if it were a slide. Orient the
Lucite block of the pipette holder as shown in Figure 8.
Fig. 8—Micropipette positioned on the microscope stage
Mounting the Heating Filament
1. Position the heating lament in the lament clamp and tighten the knob on the
bottom of the lament holder.
2. Attach both of the microforge connecting cables to the lament by tting the
socket end of each cable into the lament plugs. The cables are interchangeable
and can be used for either plug.
3. Take the free end of each cable and insert each into one of the two Filament
Output receptacles located on the side of the Microforge Control Unit. Again, it
does not matter which cable is connected to each receptacle. The connecting
cable wires from the Microforge Control Unit are not polarized, so reversing these
cables will do no harm.
MF200
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Basic Operations for Using the MF200
This section describes the nal preparations and general instructions for using the
MF200. Specic instructions are detailed for some of the MF200 common uses in
“Applications” on page 14.
NOTE: Remember that (because of microscope optics) any object seen through
the microscope objective is a reverse image of the object and will appear reversed
in orientation. For example, the heating lament (attached to the left side of the
objective) will appear through the microscope as coming from the right.
1. Turn on the power to the microscope.
2. Choose the desired lament. See “Heating Filaments” on page 5.
3. Mount and connect the heating lament. See “Mounting the Heating Filament” on
page 10.
4. Bring the lament into focus:
Without using the microscope, adjust the position of the lament by moving it
in or out and side to side until the lament wire is centered approximately 3mm
below the objective.
Looking through the microscope, move the lament in the lament clamp until
its shadow appears. Some vertical adjustment may also be required to bring the
shadow into the eld.
Using the Vertical Adjustment, bring the lament into clearer view. With the
Horizontal Adjustment, position the end loop of the lament to the far right side
of the visual eld.
5. Power up the MF200 unit. To do this, connect the AC/DC converter to the power
input jack on the Microforge Control Unit and the wall socket. A light in the
POWER switch indicates that the unit is powered up.
• Pressing the Polish push-button switch sends current through the lament
and turns on the Forge On lamp.
• Turning the HEAT dial from 0 to 100 (an arbitrary numbering scale) varies the
amount of power applied to the lament.
• An optional foot switch (WPI #MF200-FS) leaves the hands free to vary the
lament heat intensity while positioning the pipette. Some microforging
techniques will require this two-handed approach.
CAUTION: Since the working distance of the 40X LWD objective is only 3mm,
the objective lens may be damaged by prolonged exposure to the heat
produced by the heating laments. If, for example, the heat is set to 99%, the
larger lament should be used in short bursts. For longer exposure times, lower heat
settings should be used.
12 World Precision Instruments
NOTE: The underside of the Microforge Control Unit and the AC/DC converter
become warm to the touch during use. This is normal and no action is required.
6. Position the heating lament and the pipette:
With the Power on, depress the Polish button several times at various heat
settings to see the expansion of the lament loop and determine approximately
where the pipette should be positioned in relation to it.
Position a pipette by rst adjusting the stage of the microscope down and away
from the objective to provide sucient room for mounting the pipette safely on
the pipette holder.
Place the pipette in the Pipette Holder.
Position the pipette using the horizontal adjustment on the microscope stage so
that the pipette tip is slightly past the center of the objective.
Raise the stage until the lament is a few millimeters from the objective. (Fig. 8.)
Slowly move the pipette back and forth, in and out, while looking through the
microscope until the shadow of the pipette is observed.
Adjust the vertical position of the stage until the pipette is clearly visible and in
focus.
Position the pipette tip in relation to the heating lament as required by the
application.
7. Adjust the Filament Power Select switch and Heat dial.
CAUTION: It is not necessary to operate the unit at high power with the Heat
dial set at 100 if the system is used properly. This can cause the laments to
burn out prematurely.
NOTE: Whenever changing laments, turn o the power. When switching power
levels, always set the Heat dial to 0.
The Filament Select slide switch on the side of the Control Unit is marked LARGE
(or LOW) and SMALL (or HIGH). It controls the maximum power to the lament.
The Heat dial provides a range of power up to the maximum as determined by
the Filament Select switch. Always begin with the dial at the low end of the range
and increase the heat only as necessary and by small increments. The lowest
power and heat setting that can be used to accomplish a task should be used.
Higher heat than necessary may shorten lament life, as well as increase the
possibility of overheating the pipette tip.
MF200
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Table 2: Filament Power Switch
Filament LARGE (or LOW) Power Position SMALL (or HIGH) Power Posi-
tion
H2 When polishing large pipette tips,
the H2 lament works best. In
most cases LOW power will per-
form satisfactorily. Tips of 100mm
and larger may require switch-
ing the power to HIGH. See “Fire
Polishing Large Bore Pipettes” on
page 16.
Will rapidly decrease lament
life as the Heat dial approach-
es 100. Restrict time at high
heat to a minimum.
H3
and
H4
Best for polishing patch pipettes. HIGH power may be required
for pipettes above 0.5mm.
14 World Precision Instruments
Applications
Choice of laments, power and heat settings for each application vary with the use. If
the desired result is achieved, the choice of parameters is acceptable. Always use the
least amount of heat possible in order to prolong the life of the laments.
The distance that should be maintained between the lament and the pipette tip
during microforging varies depending on the tip bore, lament, power, heat settings
and application. With the exception of the applications in which a glass bead is formed
on the lament, the tip should not come in contact with the lament. In general, it is
best to begin with the tip at a safe distance from the lament and move toward it, as
necessary.
The formation of a glass bead on the lament is required for certain applications. See
“Microforging Beveled Injection Pipettes” on page 17. It is not required for the other
applications described in this manual, however, a glass bead on the lament may be
used for other applications, if desired.
Fire Polishing the Patch Clamp Pipette
Fire polishing is a two step process, involving coating the pipette and polishing it.
Step 1: Coat the Single-Channel Patch Clamp Pipette.
Coat the single-channel patch clamp pipette with Sylgard 184 before polishing. (A
simple and eective coating method has been described by Dr. Li.
WARNING: Always wear safety glasses during this procedure. Never
point the pipette at anyone. The pipette can be forcefully shot out of
its holder if not tightly secured.
1. Briey, t the pipette into a pipette holder, which is connected to a low-pressure,
clean air source. Force air through the pipette at a pressure greater than 20PSI
(for an 0.5 ID pipette) in order to prevent the Sylgard from entering the pipette tip
during the coating process.
2. After mixing the Sylgard, dip the pipette tip into the coating and remove it.
3. With the low-pressure air supply still applied, place the pipette tip over a heat gun
for two seconds in order to cure the Sylgard.
4. Remove the air supply from the pipette. The pipette is now coated and the tip
is ready to be polished following the procedure for the whole cell patch clamp
pipette as described in Step 2.
MF200
World Precision Instruments 15
Step 2: Fire Polish the Single-Channel and Whole Cell Patch
Clamp Pipette
1. Choose and install the desired lament. (See “Table 2: Filament Power Switch” on
page 13.)
2. Turn on the Control Unit power.
3. Hold down the Polish button and adjust the Heat Dial from low to high while
observing the expansion of the lament under the microscope. A slight
movement of the lament indicates that it has sucient heat and will provide
excellent polishing results in most cases.
NOTE: A red-hot lament is unnecessary and undesirable and will decrease the
life of the lament. It also heats the tip too quickly, making it dicult to control
the degree of polishing. In addition, a red-hot large lament could permanently
damage the 40X objective.
4. Place the pipette to be polished in the pipette holder.
5. Adjust the microscope stage until the pipette is in position with sucient distance
to account for lament expansion (Fig.9).
Heat off
Heat on
Fig. 9—(Left)Untreated tip
Fig. 10—(Right) Fire polished tip
6. Press Polish and observe the expansion movement of the lament (Fig.10).
7. Determine the appropriate Heat dial setting and then ne-tune the position of the
tip. A minimal change in the shape of the tip typically yields good polishing results.
Fire Polishing a Pipette Tip
To re polish a pipette tip, follow the instructions under “Step 2: Fire Polish the Single-
Channel and Whole Cell Patch Clamp Pipette” on page 15.
16 World Precision Instruments
Tip Size Reduction
Tip size reduction creates a holding pipette by rounding the tip ends and reducing the
length of the pipette tip (Fig. 11).
Fig. 11—(Right) Tip size reduction
1. Choose and install the desired lament.
(See “Table 2: Filament Power Switch” on
page 13.)
2. Turn on the Control Unit power.
3. Select the appropriate Filament power.
4. Press the Polish button and set the Heat
dial to a setting at which the lament just starts to glow red. Release the Polish
button.
5. Place the pipette to be reduced in the pipette holder. Adjust the microscope
stage until the pipette is in position with sucient distance to account for lament
expansion.
6. Turn on the heat by pressing the Polish button and observe the melting of the tip.
Maintain the heat until the desired opening size is obtained.
TIP: If the process is too slow, move the tip closer to the lament. (It is better to
do this operation very slowly in stages, in order to avoid making the tip too small.)
Fire Polishing Large Bore Pipettes
To re polish large bore tips (100–200mm), the H2 lament can be shaped or re-
formed to be slightly larger than the pipette
tip. (See Fig. 12 and 13.)
Fig. 12—(Right) Reshaped lament
This eectively provides an increase in
the heated surface area presented to
the tip with a resulting increase in the
heat directed to the large bore tip. This is
necessary to melt the thicker glass of a large
bore pipette. Larger bore tips generally
require the use of the 10X objective.
Fig. 13—Reshaped lament with large bore tip
Under some circumstance, it may be possible to use the 25X LWD objective. After re-
forming the lament, proceed to microforge as described in “Fire Polishing a Pipette
Heat off
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