There's a Lawrence Livermore technology
that as a microbiologist myself I have
been so excited to tell you about for a
really long time and in our current
interconnected, increasingly globalized
world where rapid pathogen detection has
really never been more important,
this innovation could play a really
important role in our response to COVID-19
and plus it has applications for space
exploration.
The thing I'm talking about is called
the Lawrence Livermore Microbial
Detection Array or the LLMDA and it was
developed by Crystal Jiang and her team.
So the Lawrence Livermore Microbial Detection
Array is a very powerful technology. It
can detect many thousands of microbes in
the single test. So those microbes
include viruses, bacteria, fungi, protozoa
and archaea. So in a single test the LLMDA
can quickly analyze a sample and
detect if any of tens of thousands of
different microbes are present in that
sample and having a rapid response
diagnostic like this is hugely useful in
so many situations.
Yeah so the array is
really powerful and it's really ideal.
It's ideal technology to diagnose an
unknown sample. So the unknown
sample could be a biological sample. It
could be a clinical sample such as blood
or could be an environmental sample such
as soil and the array is much faster and
cheaper than other molecular detection
tools such as sequencing.
See using
DNA sequencing on an unknown sample can
take several days requires special
chemicals called reagents that can be in
short supply and it's pretty expensive
the LLMDA however is five to ten times
cheaper than regular genetic sequencing
and gives you results within 24 hours so
how does it work? There is an existing
library of the genetic sequences of
every microorganism ever sequenced using
this bioinformatics library the LLMDA
team designed special genetic probes and
each probe tests for a particular
sequence of DNA or RNA. Small groups of
these probes when taken together can be
used to check for specific bacteria or
viruses or other microbes all the way
down to the species level. So for example
if all the probes corresponding to
genetic components of say Vibrio
fischeri light up you know that your
sample contains that
pathogen. Each of the 96 wells on this
microbial detection array contains over
a million probes and in one array you
can test for about 12,000 different
known microbes. Firstly for the sample Z
here and then we add fluorescent dyes to
fluorescently label the sample. Once the
samples are labeled we basically put the
array plate on top like that so this way
it will give the samples and the array a
chance to kind of find matching
sequences and then once the DNA sample
binds so that's where we can see
which one fluoresces. So we basically
take this plate once it's finished
binding to a machine. Some machine will
basically help us to kind of automate it.
Washing and then drying and then there's
also a camera to visualize all the
fluorescence spot on the array. Obviously
give us a pattern of what probes are
present also based on that layout and
the pattern we can identify kind of what
microbial species are present.
I just
love the efficiency and the ingenuity
here. It is so exciting and because it's
so efficient and so versatile it's
been used in some really surprising ways
like in 2014 the LLMDA was used to
analyze ancient archaeological samples
of human remains and found matches for
Yersinia pestis the bacterium that
causes the Black Plague and Vibrio
cholerae the bacterium that causes
cholera stuff like this can help
scientists who study the origins of
infectious disease and who look at
population health over time because
typically the microbial genetic
information in really old samples is so
degraded that it can be difficult to
detect using traditional sequencing
techniques.
One other application is that
we have used the array to really analyze
what pathogens can cause problems in
wounded warriors because they come back
from combat wounded. They have injury.
Often their wounds get infected
and we were able to use the array to
identify what pathogen caused those
wounds to be infected and what pathogens
could lead to wound failure
versus those that could
have the wound to be more successfully
healing and then just also recently we
were able to use the array to analyze
samples from space. So we have samples
from the International Space Station.
Environmental samples and also
astronaut samples and we put those
samples on the array to really identify
what microbes that's a space station
carry. Are any of the microbe could be
pathogenic and could affect the health
of the astronauts.
The array has also
been used in vaccine development to make
sure that vaccines don't contain any
contaminating viruses that could be
harmful or affect the vaccines efficacy
and to identify pathogens that may be
causing an outbreak where the causative
agent is unknown. Now that sounds like it
could be pretty helpful for a situation
like say a global pandemic.
Right? Now the LLMDA isn't currently
being used to directly identify SARS-CoV-2
itself because current testing
methods that rely on polymerase chain
reactions or PCR are actually faster so
the laboratory is contributing to direct
testing in many other ways which I cover
in this video here but also by looking
for ways to perform PCR testing that
don't require the use of chemicals that
are in short supply and the LLMDA is
being used to identify co-infecting
pathogens crystal and her team
anticipate that they'll be able to
identify microbes that could impact a
person's susceptibility to COVID-19 or
even promote resilience to infection
about the disease. Their studies in this
area of co-infection can provide insight
into how to diagnose and treat
individuals infected by SARS-CoV-2
especially as the virus evolves and as
genomic changes become apparent.
We work as
a team and we solve really big problems
for our country. For example we can work
with people from all kinds of
disciplines. I'm a biologist but I get to
work with engineers, computer scientists,
physicists and chemists. So together we
can really form a big team to really
kind of look at
a problem from many different
perspectives. That really kind of help us
be more creative. Have more innovative
solutions to big problems.
If you think the LLMDA is as cool as I think it
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Ss always thank you
so much for watching.
Stay safe and healthy
and I'll see you
next time.