Momentum - The Magazine for Virginia Tech Mechanical Engineering Vol. 4 No. 1 Spring 2019 | Page 21

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they have shown to be more effective than
the passive delivery of injections at reaching
cancer sites.
NanoBEADS has produced results in both
in vitro (in tumor spheroids) and in vivo (in
living mice) models showing up to 100-fold
improvements in the distribution and reten-
tion of nanoparticles in cancerous tissues.
This is a product of the five-year National
Science Foundation CAREER Award of Baha-
reh Behkam, associate professor of mechanical
engineering. Collaborators on this interdis-
ciplinary team are Rick Davis, professor of
chemical engineering, and Coy Allen, assistant
professor of biomedical sciences and patho-
biology in the Virginia-Maryland College of
Veterinary Medicine.
“You can make the most amazing drugs,
but if you cannot deliver it where it needs to
go, it cannot be very effective,” Behkam said.
“By improving the delivery, you can enhance
efficacy.”
This work, which combines expertise in
mechanical engineering, biomedical engi-
neering, chemical engineering, and veterinary
medicine, was recently detailed in Advanced
Science.
Using salmonella for good
Humans have noticed, even as far back as
Ancient Egypt, that cancer went into remis-
sion if the patient also contracted an infection
like salmonella. Neither are ideal, but humans
can treat salmonella infections more effective-
ly than cancer.
In modern times, Allen said the idea of
treating cancer with infections traces back to
the late 1800s and has evolved into immuno-
therapy, in which doctors try to activate the
immune system to attack cancerous cells.
Of course, salmonella is harmful to humans,
but a weakened version could in theory pro-
vide the benefits of immunotherapy without
the harmful effects of salmonella infection.
The concept is similar to humans receiving
a weakened flu virus in a vaccine to build
immunity.
Over six years ago, Behkam came up with
the idea of augmenting bacterial immunother-
apy to also attack cancer with conventional
anti-cancer drugs. The problem was the
passive delivery of anti-cancer drugs doesn’t
work very well.
Given her background in bio-hybrid mi-
crorobotics, she wanted to use salmonella
bacteria as autonomous vehicles to transport
the medicine, in nanoparticle form, directly to
the cancer site.
The work began with Behkam’s first doctor-
al student, Mahama Aziz Traore, constructing
the first generation of NanoBEADS by
assembling tens of polystyrene nanoparticles
onto E. coli bacteria. After thoroughly study-
ing the dynamics and control aspects of the
NanoBEADS systems for a few years, Behkam
brought Davis into the project because he had
experience creating polymer nanoparticles for
drug delivery.
“She mentioned this radically different
approach for delivering drugs and nanopar-
ticles,” Davis said. “I walked away from the
conversation thinking, ‘Man, if this thing
could work, it would be fantastic.’”
Behkam chose this particular bacterial strain,
Salmonella enterica serovar Typhimurium
VNP20009, because it has been thoroughly
studied and successfully tested in a phase one
clinical trial.
“Its (salmonella’s) job as a pathogen is to
penetrate through the tissue,” Behkam said.
“What we thought is if bacteria are so good
at moving through the tissue, how about
coupling nanomedicine with the bacterium to
carry that medicine much farther than it’d