Digital Designs and Scientific Hardware - Open-Source Lab: How to Build Your Own Hardware and Reduce Research Costs - page 227

6.5.1 OpenPCR
PCR is a biochemical technology used in molecular biology research to amplify a relative
handful of copies of a piece of DNA (or even a single piece) by making as many as you like
(e.g. thousands to millions of copies). The replications of a particular DNA sequence is use-
ful for literally dozens of applications in biology and medical science, which include (1) DNA
cloning for sequencing; (2) DNA-based phylogeny, or functional analysis of genes and ana-
lyzing gene expression levels; (3) the detection and diagnosis of infectious diseases including
both viral and bacterial infections (thus it is also useful for doing water quality testing or food
safety testing); (4) diagnosis of hereditary diseases; and (5) the identification of genetic inger-
prints, which is useful in forensic science. For all its utility, the PCR method is actually fairly
simple; it uses cycles of repeated heating and cooling (e.g. thermal cycling) of the reaction for
DNA melting and enzymatic replication of the DNA. Short DNA fragments called primers,
which contain sequences complementary to the target region along with a DNA polymerase,
enable selective and repeated amplification. A chain reaction is established where the DNA
template is exponentially amplified because the DNA generated is itself used as a template for
further replication. The more you have, the more you get and the faster you can make the next
batch. The method is extremely effective, although the commercial equipment is staggeringly
expensive, and this has set up a large and ugly intellectual property batle. The IP batle con-
tinues to this day, despite the fact that the original PCR and Taq polymerase patents expired
in 2005. For more details on negative effects of intellectual property on scientific progress and
innovation, see Chapter 3 . The answer to the unnecessarily complicated world of intellectual
property when it comes to science is, of course, to develop open-source PCR equipment.
Fortunately, this has already been accomplished as you can see in Figures 6.70(a) and (b) ,
which show the OpenPCR in action. OpenPCR is a low-cost, yet accurate, thermocycler you
build yourself, capable of reliably controlling PCR reactions for DNA detection, sequencing
and other applications. 64 You can buy the OpenPCR kit for $600 and build it in about 3 h using
only a Phillips head screwdriver, a 2 mm flathead screwdriver and a pair of pliers. The as-
sembly is reminiscent of the old laser-cut wood 3-D printers—only much easier and less time-
consuming to assemble. OpenPCR also utilizes the Arduino platform as described in detail in
Chapter 4 . The OpenPCR is completely open source including the Arduino software, 65 CAD
iles, 66 the PCB design, 67 and the BOM. 68