HP Innovation Journal Issue 15: Summer 2020 | Page 19

PRINTING FOR (LIFE) SCIENCES
Most of the printing research done at
HP is focused on what you can see, not
what you can’t. Yet the Microfluidics
Technology and Operations researchers
are finding potential in their ability to
“print” on a minuscule scale—about
a million times smaller than a single
raindrop. Innovation caught up with Raghuvir Sengupta
of HP Labs in Palo Alto to learn more.
He is part of a small team
of research engineers, data
scientists, physicists, and
chemists developing life
science applications using
a powerful sensor that
can detect substances at
very low concentrations
through a process known as
surface-enhanced Raman
scattering (SERS). SERS
sensors have the potential to
help researchers accelerate
clinical diagnostics and
antibiotic susceptibility
testing, which in turn could
speed up the process to
determine which drugs are
likely to be most effective
in treating an infection.
How does SERS tie in
with the work pharma
companies and the
CDC are doing with the
HP D300e bioprinter?
Our team has been using
the D300e to “print” small
droplets of liquid onto our
sensor. To appreciate what
makes this neat, consider
how small our sensor is:
one millimeter in diameter,
which is about as wide as
a sharp pencil point. With
the D300e, we can print
hundreds of microdroplets
within this region, and the
resulting SERS signal from
each microdroplet can be
used for accurate chemical
detection. Applications
that could significantly
benefit from inkjet-based
sensing technology include
the detection of harmful
chemicals, bacterial analysis,
and anti-counterfeiting.
How might the
bacteriological testing
performed with the D300e
be accelerated with SERS?
We are particularly
interested in using inkjetbased
SERS technology
to detect bacteria by
sensing the metabolites they
release when “stressed.”
We have been able to
identify bacteria through
this signal and are now
trying to assess whether this
mechanism can be used to
determine whether bacteria
are susceptible or resistant
to a given antibiotic.
Could SERS potentially
detect a virus?
I think that it’s possible,
and our team is currently
brainstorming potential
schemes for SERS-based
immunoassays to test
whether an individual has
been exposed to a virus
like COVID-19.
Has your research been
affected by the pandemic?
Not being able to go to the
lab has certainly interrupted
the steady acquisition of data
that our team uses to develop
new hypotheses, models, and
tests. However, I’m reminded
of something my PhD adviser
said: “Two weeks in the
library can often save you
two months of experiments.”
I hope that this time away will
give me the space to think
hard and identify the most
important questions that
our team can answer.
—SARAH MURRY