"The following is intended to help the
amateur biochemist/geneticist put together a small laboratory de
novo without spending much money. The cited articles
can almost certainly be photocopied from your nearest university
library. Unfortunately, I could not make them available on
this site due to copyright restrictions. "
Microcentrifuge:
Shawn Carlson was kind enough to feature
my do-it-yourself centrifuge design in his January
1998 Amateur Scientist column in Scientific American. My
design uses a commonly available Osterizer blender and a PVC
pipe cap for the rotor. The article can be read in the
on-line here: http://www.sciam.com/1998/0198issue/0198amsci.html.
An article describing how to use this centrifuge to
isolate DNA can be found in: The
Amateur Scientist: September 1998
Video-microscopy:
If you've ever thought about hooking
your microscope up to your camcorder without
spending any money, my plans on how to do this will be featured
in the October 1998 issue of Scientific American. The
article will be available on-line at http://www.sciam.com/1998/1098issue/1098amsci.html.
Electrophoresis Power
Supplies: Plans
for a controlled-current power supply can be found in the
Journal of Chemical Education, Vol. 67, No. 8, Aug 1990. This
supply features 0-90 mA dc, and common 120 V ac power.
I would strongly advise you to price ALL of the parts before
starting though. The 1600 ohm, 50W pot alone is worth
over $50 in Canada. The same goes for the isolation transformer
(which I decided to leave out). If I could do it all over
again I would opt for the super-cheap circuit described in
Vol. 63, No. 12, Dec 1986, of the same publication. If
you're a real cheapskate like me you could even use a bunch
of 9-V batteries in series.
Magnetic Stirrer:
Journal of Chemical Education, Vol. 69,
No. 5, May 1992, p 415(2). Anybody with a modicum of mechanical
aptitude should be able to put one of these together
with a little imagination. You will need a 4" cylindrical
magnet, a hot glue gun, a hobby motor, an old DC power pack
(or battery), a 750ml cylindrical tupperware container,
and a 100K potentiometer.
IBM Parallel Port Interface:
Am. J. Phys., Vol. 57, No. 6, June
1989. This article provides a schematic and plans for
an inexpensive ADC (analog-to-digital circuit) that uses measures
the resistance of an unknown resister and passes an 8 bit
value to the parallel port. Unfortunately 8 bits doesn't give
you much accuracy, and there are much simpler ways to interface.
When I wanted to interface my home-built UV spectrophotometer
to my PC, I simply wired the photodiode (in reverse bias)
directly to the pins of the joystick port, and it didn't cost me
a nickle.
PCR in a Teacup:
Why spent thousands of dollars
on a thermocycler when all you really need is a 150-ml
beaker (with in and out ports), water solenoid valves, 3 aquarium
water heaters, and a few other inexpensive parts? Or
better yet, why not just preheat 3 pans of water (to 92C,
54C, and 72C) and manually switch your reaction tube from
one to the other?
Chromatography: If
you want to do column or paper chromatography using only household
materials and chemicals, see the Journal of Chemical
Education, Vol. 69, No. 12, Dec 1992. If you want
to assemble a more sophisticated gel-filtration apparatus,
see Vol. 70, No. 5, May 1993. For this one you'll need to
buy gel for your bed from a biotech company.
PVC Photometer: Journal
of Chemical Education, Vol. 73, No. 3, Mar 1996. Complete
plans are included for building a spectrophotometer out
of plastic PVC piping and a radiometric light probe. They
do, however, expect you to buy this lightprobe as well
as its PC interphace box. I recommend that you simply buy
E G & G Vactec's VTB6060UV or VTB6061UV photodiode
and wire it directly to your PC gameport. This diode will
actually detect light from 200nm to 1100 nm. If you don't
know how to program your gameport interface, Email
me.
Electrophoresis:
I had a lot of articles on how to perform
electrophoresis cheaply but I lent them all
to friends and never saw them again! My favourite described
how to use a covered butter dish, a couple nails, and a chain
of 9-V batteries. Personally though I would buy some
sheets of acrylic plastic from a plastics company and some
plexiglass glue and build my own electrophoresis chamber.
Take measurements from one at school (if you're a student)
or get the measurements from spec sheets on biotech supply
company's web sites. Glue all the parts together with
the plexiglass glue then line all the inside joints with silicone.
Buy some carbon welders electrodes from the hardware
store and use them in place of expensive/hard to find platinum
wire. Use 4 9V batteries in series as your power supply.
pH Meter:See
Journal of Chemical Education, Vol. 69, No. 7, Jul 1992 if you
want to build your own, but it is far cheaper to buy a pocket
digital pH meter from a biotech supplier. Make sure it
can do 2 point calibrations. I use a Corning Chek-Mite
pH sensor, model pS30. Corning phone number is (800)-222-7740
or (607)-974-4001 in Canada.
Water Bath: Journal of
Chemical Education, Vol. 69, No. 7, Jul 1992, p. 568(2). You
can adapt this circuit to regulate a home-built incubator,
too. If you are going to be maintaining temperatures
between 20C and 40C (37.5 being very common in the lab), then
I recommend you simply submerge a $15 adjustable aquarium
heater into a large caserole dish.
Balance: Scientific American,
June 1996. This article yet shows you how to weigh in
milligrams using an old guage from your multimeter or stereo.
It is very inexpensive to build and from what I've heard,
it works really well.
Electroporator: BioTechniques
8:28-30, 1990. An upgrade to this article can be found
in BioTechniques 8:508 (for multi-samples). Also, see
Anal. Biochem 1987 Jun 163(2): 464-469. Last but not least,
see BioTechniques 16(2):312-321 Feb 1994 for a large-scale
model.
Pipetting:
Adjustable micropipettes cost a
fortune (> 300$), so I recommend buying disposable
graduated glass capillaries (100ul, 10ul etc) and a Sigma
brand plunger. If you want to build your own air-displacement
pipettor, see Journal of Chemical Education, Vol. 68, No.
4, Apr 1991. Alternatively you can use Hamilton
Syringes which are availble for many different microliter-range
quantities.
(Reproduced with permission)
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